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android-kvm / linux / 3b2c81d5feb250dfdcb0ef5825319f36c29f8336 / . / drivers / tty / serial / imx.c
blob: 90974d338f3c0bfd6b1ed8459540aab205046c89 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0+
/*
* Driver for Motorola/Freescale IMX serial ports
*
* Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
*
* Author: Sascha Hauer <sascha@saschahauer.de>
* Copyright (C) 2004 Pengutronix
*/
#include <linux/circ_buf.h>
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/platform_device.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/ktime.h>
#include <linux/pinctrl/consumer.h>
#include <linux/rational.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/dma-mapping.h>
#include <asm/irq.h>
#include <linux/dma/imx-dma.h>
#include "serial_mctrl_gpio.h"
/* Register definitions */
#define URXD0 0x0 /* Receiver Register */
#define URTX0 0x40 /* Transmitter Register */
#define UCR1 0x80 /* Control Register 1 */
#define UCR2 0x84 /* Control Register 2 */
#define UCR3 0x88 /* Control Register 3 */
#define UCR4 0x8c /* Control Register 4 */
#define UFCR 0x90 /* FIFO Control Register */
#define USR1 0x94 /* Status Register 1 */
#define USR2 0x98 /* Status Register 2 */
#define UESC 0x9c /* Escape Character Register */
#define UTIM 0xa0 /* Escape Timer Register */
#define UBIR 0xa4 /* BRM Incremental Register */
#define UBMR 0xa8 /* BRM Modulator Register */
#define UBRC 0xac /* Baud Rate Count Register */
#define IMX21_ONEMS 0xb0 /* One Millisecond register */
#define IMX1_UTS 0xd0 /* UART Test Register on i.mx1 */
#define IMX21_UTS 0xb4 /* UART Test Register on all other i.mx*/
/* UART Control Register Bit Fields.*/
#define URXD_DUMMY_READ (1<<16)
#define URXD_CHARRDY (1<<15)
#define URXD_ERR (1<<14)
#define URXD_OVRRUN (1<<13)
#define URXD_FRMERR (1<<12)
#define URXD_BRK (1<<11)
#define URXD_PRERR (1<<10)
#define URXD_RX_DATA (0xFF<<0)
#define UCR1_ADEN (1<<15) /* Auto detect interrupt */
#define UCR1_ADBR (1<<14) /* Auto detect baud rate */
#define UCR1_TRDYEN (1<<13) /* Transmitter ready interrupt enable */
#define UCR1_IDEN (1<<12) /* Idle condition interrupt */
#define UCR1_ICD_REG(x) (((x) & 3) << 10) /* idle condition detect */
#define UCR1_RRDYEN (1<<9) /* Recv ready interrupt enable */
#define UCR1_RXDMAEN (1<<8) /* Recv ready DMA enable */
#define UCR1_IREN (1<<7) /* Infrared interface enable */
#define UCR1_TXMPTYEN (1<<6) /* Transimitter empty interrupt enable */
#define UCR1_RTSDEN (1<<5) /* RTS delta interrupt enable */
#define UCR1_SNDBRK (1<<4) /* Send break */
#define UCR1_TXDMAEN (1<<3) /* Transmitter ready DMA enable */
#define IMX1_UCR1_UARTCLKEN (1<<2) /* UART clock enabled, i.mx1 only */
#define UCR1_ATDMAEN (1<<2) /* Aging DMA Timer Enable */
#define UCR1_DOZE (1<<1) /* Doze */
#define UCR1_UARTEN (1<<0) /* UART enabled */
#define UCR2_ESCI (1<<15) /* Escape seq interrupt enable */
#define UCR2_IRTS (1<<14) /* Ignore RTS pin */
#define UCR2_CTSC (1<<13) /* CTS pin control */
#define UCR2_CTS (1<<12) /* Clear to send */
#define UCR2_ESCEN (1<<11) /* Escape enable */
#define UCR2_PREN (1<<8) /* Parity enable */
#define UCR2_PROE (1<<7) /* Parity odd/even */
#define UCR2_STPB (1<<6) /* Stop */
#define UCR2_WS (1<<5) /* Word size */
#define UCR2_RTSEN (1<<4) /* Request to send interrupt enable */
#define UCR2_ATEN (1<<3) /* Aging Timer Enable */
#define UCR2_TXEN (1<<2) /* Transmitter enabled */
#define UCR2_RXEN (1<<1) /* Receiver enabled */
#define UCR2_SRST (1<<0) /* SW reset */
#define UCR3_DTREN (1<<13) /* DTR interrupt enable */
#define UCR3_PARERREN (1<<12) /* Parity enable */
#define UCR3_FRAERREN (1<<11) /* Frame error interrupt enable */
#define UCR3_DSR (1<<10) /* Data set ready */
#define UCR3_DCD (1<<9) /* Data carrier detect */
#define UCR3_RI (1<<8) /* Ring indicator */
#define UCR3_ADNIMP (1<<7) /* Autobaud Detection Not Improved */
#define UCR3_RXDSEN (1<<6) /* Receive status interrupt enable */
#define UCR3_AIRINTEN (1<<5) /* Async IR wake interrupt enable */
#define UCR3_AWAKEN (1<<4) /* Async wake interrupt enable */
#define UCR3_DTRDEN (1<<3) /* Data Terminal Ready Delta Enable. */
#define IMX21_UCR3_RXDMUXSEL (1<<2) /* RXD Muxed Input Select */
#define UCR3_INVT (1<<1) /* Inverted Infrared transmission */
#define UCR3_BPEN (1<<0) /* Preset registers enable */
#define UCR4_CTSTL_SHF 10 /* CTS trigger level shift */
#define UCR4_CTSTL_MASK 0x3F /* CTS trigger is 6 bits wide */
#define UCR4_INVR (1<<9) /* Inverted infrared reception */
#define UCR4_ENIRI (1<<8) /* Serial infrared interrupt enable */
#define UCR4_WKEN (1<<7) /* Wake interrupt enable */
#define UCR4_REF16 (1<<6) /* Ref freq 16 MHz */
#define UCR4_IDDMAEN (1<<6) /* DMA IDLE Condition Detected */
#define UCR4_IRSC (1<<5) /* IR special case */
#define UCR4_TCEN (1<<3) /* Transmit complete interrupt enable */
#define UCR4_BKEN (1<<2) /* Break condition interrupt enable */
#define UCR4_OREN (1<<1) /* Receiver overrun interrupt enable */
#define UCR4_DREN (1<<0) /* Recv data ready interrupt enable */
#define UFCR_RXTL_SHF 0 /* Receiver trigger level shift */
#define UFCR_RXTL_MASK 0x3F /* Receiver trigger 6 bits wide */
#define UFCR_DCEDTE (1<<6) /* DCE/DTE mode select */
#define UFCR_RFDIV (7<<7) /* Reference freq divider mask */
#define UFCR_RFDIV_REG(x) (((x) < 7 ? 6 - (x) : 6) << 7)
#define UFCR_TXTL_SHF 10 /* Transmitter trigger level shift */
#define USR1_PARITYERR (1<<15) /* Parity error interrupt flag */
#define USR1_RTSS (1<<14) /* RTS pin status */
#define USR1_TRDY (1<<13) /* Transmitter ready interrupt/dma flag */
#define USR1_RTSD (1<<12) /* RTS delta */
#define USR1_ESCF (1<<11) /* Escape seq interrupt flag */
#define USR1_FRAMERR (1<<10) /* Frame error interrupt flag */
#define USR1_RRDY (1<<9) /* Receiver ready interrupt/dma flag */
#define USR1_AGTIM (1<<8) /* Ageing timer interrupt flag */
#define USR1_DTRD (1<<7) /* DTR Delta */
#define USR1_RXDS (1<<6) /* Receiver idle interrupt flag */
#define USR1_AIRINT (1<<5) /* Async IR wake interrupt flag */
#define USR1_AWAKE (1<<4) /* Aysnc wake interrupt flag */
#define USR2_ADET (1<<15) /* Auto baud rate detect complete */
#define USR2_TXFE (1<<14) /* Transmit buffer FIFO empty */
#define USR2_DTRF (1<<13) /* DTR edge interrupt flag */
#define USR2_IDLE (1<<12) /* Idle condition */
#define USR2_RIDELT (1<<10) /* Ring Interrupt Delta */
#define USR2_RIIN (1<<9) /* Ring Indicator Input */
#define USR2_IRINT (1<<8) /* Serial infrared interrupt flag */
#define USR2_WAKE (1<<7) /* Wake */
#define USR2_DCDIN (1<<5) /* Data Carrier Detect Input */
#define USR2_RTSF (1<<4) /* RTS edge interrupt flag */
#define USR2_TXDC (1<<3) /* Transmitter complete */
#define USR2_BRCD (1<<2) /* Break condition */
#define USR2_ORE (1<<1) /* Overrun error */
#define USR2_RDR (1<<0) /* Recv data ready */
#define UTS_FRCPERR (1<<13) /* Force parity error */
#define UTS_LOOP (1<<12) /* Loop tx and rx */
#define UTS_TXEMPTY (1<<6) /* TxFIFO empty */
#define UTS_RXEMPTY (1<<5) /* RxFIFO empty */
#define UTS_TXFULL (1<<4) /* TxFIFO full */
#define UTS_RXFULL (1<<3) /* RxFIFO full */
#define UTS_SOFTRST (1<<0) /* Software reset */
/* We've been assigned a range on the "Low-density serial ports" major */
#define SERIAL_IMX_MAJOR 207
#define MINOR_START 16
#define DEV_NAME "ttymxc"
/*
* This determines how often we check the modem status signals
* for any change. They generally aren't connected to an IRQ
* so we have to poll them. We also check immediately before
* filling the TX fifo incase CTS has been dropped.
*/
#define MCTRL_TIMEOUT (250*HZ/1000)
#define DRIVER_NAME "IMX-uart"
#define UART_NR 8
/* i.MX21 type uart runs on all i.mx except i.MX1 and i.MX6q */
enum imx_uart_type {
IMX1_UART,
IMX21_UART,
};
/* device type dependent stuff */
struct imx_uart_data {
unsigned uts_reg;
enum imx_uart_type devtype;
};
enum imx_tx_state {
OFF,
WAIT_AFTER_RTS,
SEND,
WAIT_AFTER_SEND,
};
struct imx_port {
struct uart_port port;
struct timer_list timer;
unsigned int old_status;
unsigned int have_rtscts:1;
unsigned int have_rtsgpio:1;
unsigned int dte_mode:1;
unsigned int inverted_tx:1;
unsigned int inverted_rx:1;
struct clk *clk_ipg;
struct clk *clk_per;
const struct imx_uart_data *devdata;
struct mctrl_gpios *gpios;
/* counter to stop 0xff flood */
int idle_counter;
/* DMA fields */
unsigned int dma_is_enabled:1;
unsigned int dma_is_rxing:1;
unsigned int dma_is_txing:1;
struct dma_chan *dma_chan_rx, *dma_chan_tx;
struct scatterlist rx_sgl, tx_sgl[2];
void *rx_buf;
struct circ_buf rx_ring;
unsigned int rx_buf_size;
unsigned int rx_period_length;
unsigned int rx_periods;
dma_cookie_t rx_cookie;
unsigned int tx_bytes;
unsigned int dma_tx_nents;
unsigned int saved_reg[10];
bool context_saved;
enum imx_tx_state tx_state;
struct hrtimer trigger_start_tx;
struct hrtimer trigger_stop_tx;
};
struct imx_port_ucrs {
unsigned int ucr1;
unsigned int ucr2;
unsigned int ucr3;
};
static const struct imx_uart_data imx_uart_imx1_devdata = {
.uts_reg = IMX1_UTS,
.devtype = IMX1_UART,
};
static const struct imx_uart_data imx_uart_imx21_devdata = {
.uts_reg = IMX21_UTS,
.devtype = IMX21_UART,
};
static const struct of_device_id imx_uart_dt_ids[] = {
/*
* For reasons unknown to me, some UART devices (e.g. imx6ul's) are
* compatible to fsl,imx6q-uart, but not fsl,imx21-uart, while the
* original imx6q's UART is compatible to fsl,imx21-uart. This driver
* doesn't make any distinction between these two variants.
*/
{ .compatible = "fsl,imx6q-uart", .data = &imx_uart_imx21_devdata, },
{ .compatible = "fsl,imx1-uart", .data = &imx_uart_imx1_devdata, },
{ .compatible = "fsl,imx21-uart", .data = &imx_uart_imx21_devdata, },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, imx_uart_dt_ids);
static inline struct imx_port *to_imx_port(struct uart_port *port)
{
return container_of(port, struct imx_port, port);
}
static inline void imx_uart_writel(struct imx_port *sport, u32 val, u32 offset)
{
writel(val, sport->port.membase + offset);
}
static inline u32 imx_uart_readl(struct imx_port *sport, u32 offset)
{
return readl(sport->port.membase + offset);
}
static inline unsigned imx_uart_uts_reg(struct imx_port *sport)
{
return sport->devdata->uts_reg;
}
static inline int imx_uart_is_imx1(struct imx_port *sport)
{
return sport->devdata->devtype == IMX1_UART;
}
/*
* Save and restore functions for UCR1, UCR2 and UCR3 registers
*/
#if IS_ENABLED(CONFIG_SERIAL_IMX_CONSOLE)
static void imx_uart_ucrs_save(struct imx_port *sport,
struct imx_port_ucrs *ucr)
{
/* save control registers */
ucr->ucr1 = imx_uart_readl(sport, UCR1);
ucr->ucr2 = imx_uart_readl(sport, UCR2);
ucr->ucr3 = imx_uart_readl(sport, UCR3);
}
static void imx_uart_ucrs_restore(struct imx_port *sport,
struct imx_port_ucrs *ucr)
{
/* restore control registers */
imx_uart_writel(sport, ucr->ucr1, UCR1);
imx_uart_writel(sport, ucr->ucr2, UCR2);
imx_uart_writel(sport, ucr->ucr3, UCR3);
}
#endif
/* called with port.lock taken and irqs caller dependent */
static void imx_uart_rts_active(struct imx_port *sport, u32 *ucr2)
{
*ucr2 &= ~(UCR2_CTSC | UCR2_CTS);
mctrl_gpio_set(sport->gpios, sport->port.mctrl | TIOCM_RTS);
}
/* called with port.lock taken and irqs caller dependent */
static void imx_uart_rts_inactive(struct imx_port *sport, u32 *ucr2)
{
*ucr2 &= ~UCR2_CTSC;
*ucr2 |= UCR2_CTS;
mctrl_gpio_set(sport->gpios, sport->port.mctrl & ~TIOCM_RTS);
}
static void start_hrtimer_ms(struct hrtimer *hrt, unsigned long msec)
{
hrtimer_start(hrt, ms_to_ktime(msec), HRTIMER_MODE_REL);
}
/* called with port.lock taken and irqs off */
static void imx_uart_soft_reset(struct imx_port *sport)
{
int i = 10;
u32 ucr2, ubir, ubmr, uts;
/*
* According to the Reference Manual description of the UART SRST bit:
*
* "Reset the transmit and receive state machines,
* all FIFOs and register USR1, USR2, UBIR, UBMR, UBRC, URXD, UTXD
* and UTS[6-3]".
*
* We don't need to restore the old values from USR1, USR2, URXD and
* UTXD. UBRC is read only, so only save/restore the other three
* registers.
*/
ubir = imx_uart_readl(sport, UBIR);
ubmr = imx_uart_readl(sport, UBMR);
uts = imx_uart_readl(sport, IMX21_UTS);
ucr2 = imx_uart_readl(sport, UCR2);
imx_uart_writel(sport, ucr2 & ~UCR2_SRST, UCR2);
while (!(imx_uart_readl(sport, UCR2) & UCR2_SRST) && (--i > 0))
udelay(1);
/* Restore the registers */
imx_uart_writel(sport, ubir, UBIR);
imx_uart_writel(sport, ubmr, UBMR);
imx_uart_writel(sport, uts, IMX21_UTS);
sport->idle_counter = 0;
}
static void imx_uart_disable_loopback_rs485(struct imx_port *sport)
{
unsigned int uts;
/* See SER_RS485_ENABLED/UTS_LOOP comment in imx_uart_probe() */
uts = imx_uart_readl(sport, imx_uart_uts_reg(sport));
uts &= ~UTS_LOOP;
imx_uart_writel(sport, uts, imx_uart_uts_reg(sport));
}
/* called with port.lock taken and irqs off */
static void imx_uart_start_rx(struct uart_port *port)
{
struct imx_port *sport = to_imx_port(port);
unsigned int ucr1, ucr2;
ucr1 = imx_uart_readl(sport, UCR1);
ucr2 = imx_uart_readl(sport, UCR2);
ucr2 |= UCR2_RXEN;
if (sport->dma_is_enabled) {
ucr1 |= UCR1_RXDMAEN | UCR1_ATDMAEN;
} else {
ucr1 |= UCR1_RRDYEN;
ucr2 |= UCR2_ATEN;
}
/* Write UCR2 first as it includes RXEN */
imx_uart_writel(sport, ucr2, UCR2);
imx_uart_writel(sport, ucr1, UCR1);
imx_uart_disable_loopback_rs485(sport);
}
/* called with port.lock taken and irqs off */
static void imx_uart_stop_tx(struct uart_port *port)
{
struct imx_port *sport = to_imx_port(port);
u32 ucr1, ucr4, usr2;
if (sport->tx_state == OFF)
return;
/*
* We are maybe in the SMP context, so if the DMA TX thread is running
* on other cpu, we have to wait for it to finish.
*/
if (sport->dma_is_txing)
return;
ucr1 = imx_uart_readl(sport, UCR1);
imx_uart_writel(sport, ucr1 & ~UCR1_TRDYEN, UCR1);
ucr4 = imx_uart_readl(sport, UCR4);
usr2 = imx_uart_readl(sport, USR2);
if ((!(usr2 & USR2_TXDC)) && (ucr4 & UCR4_TCEN)) {
/* The shifter is still busy, so retry once TC triggers */
return;
}
ucr4 &= ~UCR4_TCEN;
imx_uart_writel(sport, ucr4, UCR4);
/* in rs485 mode disable transmitter */
if (port->rs485.flags & SER_RS485_ENABLED) {
if (sport->tx_state == SEND) {
sport->tx_state = WAIT_AFTER_SEND;
if (port->rs485.delay_rts_after_send > 0) {
start_hrtimer_ms(&sport->trigger_stop_tx,
port->rs485.delay_rts_after_send);
return;
}
/* continue without any delay */
}
if (sport->tx_state == WAIT_AFTER_RTS ||
sport->tx_state == WAIT_AFTER_SEND) {
u32 ucr2;
hrtimer_try_to_cancel(&sport->trigger_start_tx);
ucr2 = imx_uart_readl(sport, UCR2);
if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND)
imx_uart_rts_active(sport, &ucr2);
else
imx_uart_rts_inactive(sport, &ucr2);
imx_uart_writel(sport, ucr2, UCR2);
if (!port->rs485_rx_during_tx_gpio)
imx_uart_start_rx(port);
sport->tx_state = OFF;
}
} else {
sport->tx_state = OFF;
}
}
static void imx_uart_stop_rx_with_loopback_ctrl(struct uart_port *port, bool loopback)
{
struct imx_port *sport = to_imx_port(port);
u32 ucr1, ucr2, ucr4, uts;
ucr1 = imx_uart_readl(sport, UCR1);
ucr2 = imx_uart_readl(sport, UCR2);
ucr4 = imx_uart_readl(sport, UCR4);
if (sport->dma_is_enabled) {
ucr1 &= ~(UCR1_RXDMAEN | UCR1_ATDMAEN);
} else {
ucr1 &= ~UCR1_RRDYEN;
ucr2 &= ~UCR2_ATEN;
ucr4 &= ~UCR4_OREN;
}
imx_uart_writel(sport, ucr1, UCR1);
imx_uart_writel(sport, ucr4, UCR4);
/* See SER_RS485_ENABLED/UTS_LOOP comment in imx_uart_probe() */
if (port->rs485.flags & SER_RS485_ENABLED &&
port->rs485.flags & SER_RS485_RTS_ON_SEND &&
sport->have_rtscts && !sport->have_rtsgpio && loopback) {
uts = imx_uart_readl(sport, imx_uart_uts_reg(sport));
uts |= UTS_LOOP;
imx_uart_writel(sport, uts, imx_uart_uts_reg(sport));
ucr2 |= UCR2_RXEN;
} else {
ucr2 &= ~UCR2_RXEN;
}
imx_uart_writel(sport, ucr2, UCR2);
}
/* called with port.lock taken and irqs off */
static void imx_uart_stop_rx(struct uart_port *port)
{
/*
* Stop RX and enable loopback in order to make sure RS485 bus
* is not blocked. Se comment in imx_uart_probe().
*/
imx_uart_stop_rx_with_loopback_ctrl(port, true);
}
/* called with port.lock taken and irqs off */
static void imx_uart_enable_ms(struct uart_port *port)
{
struct imx_port *sport = to_imx_port(port);
mod_timer(&sport->timer, jiffies);
mctrl_gpio_enable_ms(sport->gpios);
}
static void imx_uart_dma_tx(struct imx_port *sport);
/* called with port.lock taken and irqs off */
static inline void imx_uart_transmit_buffer(struct imx_port *sport)
{
struct tty_port *tport = &sport->port.state->port;
unsigned char c;
if (sport->port.x_char) {
/* Send next char */
imx_uart_writel(sport, sport->port.x_char, URTX0);
sport->port.icount.tx++;
sport->port.x_char = 0;
return;
}
if (kfifo_is_empty(&tport->xmit_fifo) ||
uart_tx_stopped(&sport->port)) {
imx_uart_stop_tx(&sport->port);
return;
}
if (sport->dma_is_enabled) {
u32 ucr1;
/*
* We've just sent a X-char Ensure the TX DMA is enabled
* and the TX IRQ is disabled.
**/
ucr1 = imx_uart_readl(sport, UCR1);
ucr1 &= ~UCR1_TRDYEN;
if (sport->dma_is_txing) {
ucr1 |= UCR1_TXDMAEN;
imx_uart_writel(sport, ucr1, UCR1);
} else {
imx_uart_writel(sport, ucr1, UCR1);
imx_uart_dma_tx(sport);
}
return;
}
while (!(imx_uart_readl(sport, imx_uart_uts_reg(sport)) & UTS_TXFULL) &&
uart_fifo_get(&sport->port, &c))
imx_uart_writel(sport, c, URTX0);
if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS)
uart_write_wakeup(&sport->port);
if (kfifo_is_empty(&tport->xmit_fifo))
imx_uart_stop_tx(&sport->port);
}
static void imx_uart_dma_tx_callback(void *data)
{
struct imx_port *sport = data;
struct tty_port *tport = &sport->port.state->port;
struct scatterlist *sgl = &sport->tx_sgl[0];
unsigned long flags;
u32 ucr1;
uart_port_lock_irqsave(&sport->port, &flags);
dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE);
ucr1 = imx_uart_readl(sport, UCR1);
ucr1 &= ~UCR1_TXDMAEN;
imx_uart_writel(sport, ucr1, UCR1);
uart_xmit_advance(&sport->port, sport->tx_bytes);
dev_dbg(sport->port.dev, "we finish the TX DMA.\n");
sport->dma_is_txing = 0;
if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS)
uart_write_wakeup(&sport->port);
if (!kfifo_is_empty(&tport->xmit_fifo) &&
!uart_tx_stopped(&sport->port))
imx_uart_dma_tx(sport);
else if (sport->port.rs485.flags & SER_RS485_ENABLED) {
u32 ucr4 = imx_uart_readl(sport, UCR4);
ucr4 |= UCR4_TCEN;
imx_uart_writel(sport, ucr4, UCR4);
}
uart_port_unlock_irqrestore(&sport->port, flags);
}
/* called with port.lock taken and irqs off */
static void imx_uart_dma_tx(struct imx_port *sport)
{
struct tty_port *tport = &sport->port.state->port;
struct scatterlist *sgl = sport->tx_sgl;
struct dma_async_tx_descriptor *desc;
struct dma_chan *chan = sport->dma_chan_tx;
struct device *dev = sport->port.dev;
u32 ucr1, ucr4;
int ret;
if (sport->dma_is_txing)
return;
ucr4 = imx_uart_readl(sport, UCR4);
ucr4 &= ~UCR4_TCEN;
imx_uart_writel(sport, ucr4, UCR4);
sg_init_table(sgl, ARRAY_SIZE(sport->tx_sgl));
sport->tx_bytes = kfifo_len(&tport->xmit_fifo);
sport->dma_tx_nents = kfifo_dma_out_prepare(&tport->xmit_fifo, sgl,
ARRAY_SIZE(sport->tx_sgl), sport->tx_bytes);
ret = dma_map_sg(dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE);
if (ret == 0) {
dev_err(dev, "DMA mapping error for TX.\n");
return;
}
desc = dmaengine_prep_slave_sg(chan, sgl, ret,
DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT);
if (!desc) {
dma_unmap_sg(dev, sgl, sport->dma_tx_nents,
DMA_TO_DEVICE);
dev_err(dev, "We cannot prepare for the TX slave dma!\n");
return;
}
desc->callback = imx_uart_dma_tx_callback;
desc->callback_param = sport;
dev_dbg(dev, "TX: prepare to send %u bytes by DMA.\n", sport->tx_bytes);
ucr1 = imx_uart_readl(sport, UCR1);
ucr1 |= UCR1_TXDMAEN;
imx_uart_writel(sport, ucr1, UCR1);
/* fire it */
sport->dma_is_txing = 1;
dmaengine_submit(desc);
dma_async_issue_pending(chan);
return;
}
/* called with port.lock taken and irqs off */
static void imx_uart_start_tx(struct uart_port *port)
{
struct imx_port *sport = to_imx_port(port);
struct tty_port *tport = &sport->port.state->port;
u32 ucr1;
if (!sport->port.x_char && kfifo_is_empty(&tport->xmit_fifo))
return;
/*
* We cannot simply do nothing here if sport->tx_state == SEND already
* because UCR1_TXMPTYEN might already have been cleared in
* imx_uart_stop_tx(), but tx_state is still SEND.
*/
if (port->rs485.flags & SER_RS485_ENABLED) {
if (sport->tx_state == OFF) {
u32 ucr2 = imx_uart_readl(sport, UCR2);
if (port->rs485.flags & SER_RS485_RTS_ON_SEND)
imx_uart_rts_active(sport, &ucr2);
else
imx_uart_rts_inactive(sport, &ucr2);
imx_uart_writel(sport, ucr2, UCR2);
/*
* Since we are about to transmit we can not stop RX
* with loopback enabled because that will make our
* transmitted data being just looped to RX.
*/
if (!(port->rs485.flags & SER_RS485_RX_DURING_TX) &&
!port->rs485_rx_during_tx_gpio)
imx_uart_stop_rx_with_loopback_ctrl(port, false);
sport->tx_state = WAIT_AFTER_RTS;
if (port->rs485.delay_rts_before_send > 0) {
start_hrtimer_ms(&sport->trigger_start_tx,
port->rs485.delay_rts_before_send);
return;
}
/* continue without any delay */
}
if (sport->tx_state == WAIT_AFTER_SEND
|| sport->tx_state == WAIT_AFTER_RTS) {
hrtimer_try_to_cancel(&sport->trigger_stop_tx);
/*
* Enable transmitter and shifter empty irq only if DMA
* is off. In the DMA case this is done in the
* tx-callback.
*/
if (!sport->dma_is_enabled) {
u32 ucr4 = imx_uart_readl(sport, UCR4);
ucr4 |= UCR4_TCEN;
imx_uart_writel(sport, ucr4, UCR4);
}
sport->tx_state = SEND;
}
} else {
sport->tx_state = SEND;
}
if (!sport->dma_is_enabled) {
ucr1 = imx_uart_readl(sport, UCR1);
imx_uart_writel(sport, ucr1 | UCR1_TRDYEN, UCR1);
}
if (sport->dma_is_enabled) {
if (sport->port.x_char) {
/* We have X-char to send, so enable TX IRQ and
* disable TX DMA to let TX interrupt to send X-char */
ucr1 = imx_uart_readl(sport, UCR1);
ucr1 &= ~UCR1_TXDMAEN;
ucr1 |= UCR1_TRDYEN;
imx_uart_writel(sport, ucr1, UCR1);
return;
}
if (!kfifo_is_empty(&tport->xmit_fifo) &&
!uart_tx_stopped(port))
imx_uart_dma_tx(sport);
return;
}
}
static irqreturn_t __imx_uart_rtsint(int irq, void *dev_id)
{
struct imx_port *sport = dev_id;
u32 usr1;
imx_uart_writel(sport, USR1_RTSD, USR1);
usr1 = imx_uart_readl(sport, USR1) & USR1_RTSS;
/*
* Update sport->old_status here, so any follow-up calls to
* imx_uart_mctrl_check() will be able to recognize that RTS
* state changed since last imx_uart_mctrl_check() call.
*
* In case RTS has been detected as asserted here and later on
* deasserted by the time imx_uart_mctrl_check() was called,
* imx_uart_mctrl_check() can detect the RTS state change and
* trigger uart_handle_cts_change() to unblock the port for
* further TX transfers.
*/
if (usr1 & USR1_RTSS)
sport->old_status |= TIOCM_CTS;
else
sport->old_status &= ~TIOCM_CTS;
uart_handle_cts_change(&sport->port, usr1);
wake_up_interruptible(&sport->port.state->port.delta_msr_wait);
return IRQ_HANDLED;
}
static irqreturn_t imx_uart_rtsint(int irq, void *dev_id)
{
struct imx_port *sport = dev_id;
irqreturn_t ret;
uart_port_lock(&sport->port);
ret = __imx_uart_rtsint(irq, dev_id);
uart_port_unlock(&sport->port);
return ret;
}
static irqreturn_t imx_uart_txint(int irq, void *dev_id)
{
struct imx_port *sport = dev_id;
uart_port_lock(&sport->port);
imx_uart_transmit_buffer(sport);
uart_port_unlock(&sport->port);
return IRQ_HANDLED;
}
/* Check if hardware Rx flood is in progress, and issue soft reset to stop it.
* This is to be called from Rx ISRs only when some bytes were actually
* received.
*
* A way to reproduce the flood (checked on iMX6SX) is: open iMX UART at 9600
* 8N1, and from external source send 0xf0 char at 115200 8N1. In about 90% of
* cases this starts a flood of "receiving" of 0xff characters by the iMX6 UART
* that is terminated by any activity on RxD line, or could be stopped by
* issuing soft reset to the UART (just stop/start of RX does not help). Note
* that what we do here is sending isolated start bit about 2.4 times shorter
* than it is to be on UART configured baud rate.
*/
static void imx_uart_check_flood(struct imx_port *sport, u32 usr2)
{
/* To detect hardware 0xff flood we monitor RxD line between RX
* interrupts to isolate "receiving" of char(s) with no activity
* on RxD line, that'd never happen on actual data transfers.
*
* We use USR2_WAKE bit to check for activity on RxD line, but we have a
* race here if we clear USR2_WAKE when receiving of a char is in
* progress, so we might get RX interrupt later with USR2_WAKE bit
* cleared. Note though that as we don't try to clear USR2_WAKE when we
* detected no activity, this race may hide actual activity only once.
*
* Yet another case where receive interrupt may occur without RxD
* activity is expiration of aging timer, so we consider this as well.
*
* We use 'idle_counter' to ensure that we got at least so many RX
* interrupts without any detected activity on RxD line. 2 cases
* described plus 1 to be on the safe side gives us a margin of 3,
* below. In practice I was not able to produce a false positive to
* induce soft reset at regular data transfers even using 1 as the
* margin, so 3 is actually very strong.
*
* We count interrupts, not chars in 'idle-counter' for simplicity.
*/
if (usr2 & USR2_WAKE) {
imx_uart_writel(sport, USR2_WAKE, USR2);
sport->idle_counter = 0;
} else if (++sport->idle_counter > 3) {
dev_warn(sport->port.dev, "RX flood detected: soft reset.");
imx_uart_soft_reset(sport); /* also clears 'sport->idle_counter' */
}
}
static irqreturn_t __imx_uart_rxint(int irq, void *dev_id)
{
struct imx_port *sport = dev_id;
struct tty_port *port = &sport->port.state->port;
u32 usr2, rx;
/* If we received something, check for 0xff flood */
usr2 = imx_uart_readl(sport, USR2);
if (usr2 & USR2_RDR)
imx_uart_check_flood(sport, usr2);
while ((rx = imx_uart_readl(sport, URXD0)) & URXD_CHARRDY) {
unsigned int flg = TTY_NORMAL;
sport->port.icount.rx++;
if (unlikely(rx & URXD_ERR)) {
if (rx & URXD_BRK) {
sport->port.icount.brk++;
if (uart_handle_break(&sport->port))
continue;
}
else if (rx & URXD_PRERR)
sport->port.icount.parity++;
else if (rx & URXD_FRMERR)
sport->port.icount.frame++;
if (rx & URXD_OVRRUN)
sport->port.icount.overrun++;
if (rx & sport->port.ignore_status_mask)
continue;
rx &= (sport->port.read_status_mask | 0xFF);
if (rx & URXD_BRK)
flg = TTY_BREAK;
else if (rx & URXD_PRERR)
flg = TTY_PARITY;
else if (rx & URXD_FRMERR)
flg = TTY_FRAME;
if (rx & URXD_OVRRUN)
flg = TTY_OVERRUN;
sport->port.sysrq = 0;
} else if (uart_handle_sysrq_char(&sport->port, (unsigned char)rx)) {
continue;
}
if (sport->port.ignore_status_mask & URXD_DUMMY_READ)
continue;
if (tty_insert_flip_char(port, rx, flg) == 0)
sport->port.icount.buf_overrun++;
}
tty_flip_buffer_push(port);
return IRQ_HANDLED;
}
static irqreturn_t imx_uart_rxint(int irq, void *dev_id)
{
struct imx_port *sport = dev_id;
irqreturn_t ret;
uart_port_lock(&sport->port);
ret = __imx_uart_rxint(irq, dev_id);
uart_port_unlock(&sport->port);
return ret;
}
static void imx_uart_clear_rx_errors(struct imx_port *sport);
/*
* We have a modem side uart, so the meanings of RTS and CTS are inverted.
*/
static unsigned int imx_uart_get_hwmctrl(struct imx_port *sport)
{
unsigned int tmp = TIOCM_DSR;
unsigned usr1 = imx_uart_readl(sport, USR1);
unsigned usr2 = imx_uart_readl(sport, USR2);
if (usr1 & USR1_RTSS)
tmp |= TIOCM_CTS;
/* in DCE mode DCDIN is always 0 */
if (!(usr2 & USR2_DCDIN))
tmp |= TIOCM_CAR;
if (sport->dte_mode)
if (!(imx_uart_readl(sport, USR2) & USR2_RIIN))
tmp |= TIOCM_RI;
return tmp;
}
/*
* Handle any change of modem status signal since we were last called.
*/
static void imx_uart_mctrl_check(struct imx_port *sport)
{
unsigned int status, changed;
status = imx_uart_get_hwmctrl(sport);
changed = status ^ sport->old_status;
if (changed == 0)
return;
sport->old_status = status;
if (changed & TIOCM_RI && status & TIOCM_RI)
sport->port.icount.rng++;
if (changed & TIOCM_DSR)
sport->port.icount.dsr++;
if (changed & TIOCM_CAR)
uart_handle_dcd_change(&sport->port, status & TIOCM_CAR);
if (changed & TIOCM_CTS)
uart_handle_cts_change(&sport->port, status & TIOCM_CTS);
wake_up_interruptible(&sport->port.state->port.delta_msr_wait);
}
static irqreturn_t imx_uart_int(int irq, void *dev_id)
{
struct imx_port *sport = dev_id;
unsigned int usr1, usr2, ucr1, ucr2, ucr3, ucr4;
irqreturn_t ret = IRQ_NONE;
uart_port_lock(&sport->port);
usr1 = imx_uart_readl(sport, USR1);
usr2 = imx_uart_readl(sport, USR2);
ucr1 = imx_uart_readl(sport, UCR1);
ucr2 = imx_uart_readl(sport, UCR2);
ucr3 = imx_uart_readl(sport, UCR3);
ucr4 = imx_uart_readl(sport, UCR4);
/*
* Even if a condition is true that can trigger an irq only handle it if
* the respective irq source is enabled. This prevents some undesired
* actions, for example if a character that sits in the RX FIFO and that
* should be fetched via DMA is tried to be fetched using PIO. Or the
* receiver is currently off and so reading from URXD0 results in an
* exception. So just mask the (raw) status bits for disabled irqs.
*/
if ((ucr1 & UCR1_RRDYEN) == 0)
usr1 &= ~USR1_RRDY;
if ((ucr2 & UCR2_ATEN) == 0)
usr1 &= ~USR1_AGTIM;
if ((ucr1 & UCR1_TRDYEN) == 0)
usr1 &= ~USR1_TRDY;
if ((ucr4 & UCR4_TCEN) == 0)
usr2 &= ~USR2_TXDC;
if ((ucr3 & UCR3_DTRDEN) == 0)
usr1 &= ~USR1_DTRD;
if ((ucr1 & UCR1_RTSDEN) == 0)
usr1 &= ~USR1_RTSD;
if ((ucr3 & UCR3_AWAKEN) == 0)
usr1 &= ~USR1_AWAKE;
if ((ucr4 & UCR4_OREN) == 0)
usr2 &= ~USR2_ORE;
if (usr1 & (USR1_RRDY | USR1_AGTIM)) {
imx_uart_writel(sport, USR1_AGTIM, USR1);
__imx_uart_rxint(irq, dev_id);
ret = IRQ_HANDLED;
}
if ((usr1 & USR1_TRDY) || (usr2 & USR2_TXDC)) {
imx_uart_transmit_buffer(sport);
ret = IRQ_HANDLED;
}
if (usr1 & USR1_DTRD) {
imx_uart_writel(sport, USR1_DTRD, USR1);
imx_uart_mctrl_check(sport);
ret = IRQ_HANDLED;
}
if (usr1 & USR1_RTSD) {
__imx_uart_rtsint(irq, dev_id);
ret = IRQ_HANDLED;
}
if (usr1 & USR1_AWAKE) {
imx_uart_writel(sport, USR1_AWAKE, USR1);
ret = IRQ_HANDLED;
}
if (usr2 & USR2_ORE) {
sport->port.icount.overrun++;
imx_uart_writel(sport, USR2_ORE, USR2);
ret = IRQ_HANDLED;
}
uart_port_unlock(&sport->port);
return ret;
}
/*
* Return TIOCSER_TEMT when transmitter is not busy.
*/
static unsigned int imx_uart_tx_empty(struct uart_port *port)
{
struct imx_port *sport = to_imx_port(port);
unsigned int ret;
ret = (imx_uart_readl(sport, USR2) & USR2_TXDC) ? TIOCSER_TEMT : 0;
/* If the TX DMA is working, return 0. */
if (sport->dma_is_txing)
ret = 0;
return ret;
}
/* called with port.lock taken and irqs off */
static unsigned int imx_uart_get_mctrl(struct uart_port *port)
{
struct imx_port *sport = to_imx_port(port);
unsigned int ret = imx_uart_get_hwmctrl(sport);
mctrl_gpio_get(sport->gpios, &ret);
return ret;
}
/* called with port.lock taken and irqs off */
static void imx_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
struct imx_port *sport = to_imx_port(port);
u32 ucr3, uts;
if (!(port->rs485.flags & SER_RS485_ENABLED)) {
u32 ucr2;
/*
* Turn off autoRTS if RTS is lowered and restore autoRTS
* setting if RTS is raised.
*/
ucr2 = imx_uart_readl(sport, UCR2);
ucr2 &= ~(UCR2_CTS | UCR2_CTSC);
if (mctrl & TIOCM_RTS) {
ucr2 |= UCR2_CTS;
/*
* UCR2_IRTS is unset if and only if the port is
* configured for CRTSCTS, so we use inverted UCR2_IRTS
* to get the state to restore to.
*/
if (!(ucr2 & UCR2_IRTS))
ucr2 |= UCR2_CTSC;
}
imx_uart_writel(sport, ucr2, UCR2);
}
ucr3 = imx_uart_readl(sport, UCR3) & ~UCR3_DSR;
if (!(mctrl & TIOCM_DTR))
ucr3 |= UCR3_DSR;
imx_uart_writel(sport, ucr3, UCR3);
uts = imx_uart_readl(sport, imx_uart_uts_reg(sport)) & ~UTS_LOOP;
if (mctrl & TIOCM_LOOP)
uts |= UTS_LOOP;
imx_uart_writel(sport, uts, imx_uart_uts_reg(sport));
mctrl_gpio_set(sport->gpios, mctrl);
}
/*
* Interrupts always disabled.
*/
static void imx_uart_break_ctl(struct uart_port *port, int break_state)
{
struct imx_port *sport = to_imx_port(port);
unsigned long flags;
u32 ucr1;
uart_port_lock_irqsave(&sport->port, &flags);
ucr1 = imx_uart_readl(sport, UCR1) & ~UCR1_SNDBRK;
if (break_state != 0)
ucr1 |= UCR1_SNDBRK;
imx_uart_writel(sport, ucr1, UCR1);
uart_port_unlock_irqrestore(&sport->port, flags);
}
/*
* This is our per-port timeout handler, for checking the
* modem status signals.
*/
static void imx_uart_timeout(struct timer_list *t)
{
struct imx_port *sport = from_timer(sport, t, timer);
unsigned long flags;
if (sport->port.state) {
uart_port_lock_irqsave(&sport->port, &flags);
imx_uart_mctrl_check(sport);
uart_port_unlock_irqrestore(&sport->port, flags);
mod_timer(&sport->timer, jiffies + MCTRL_TIMEOUT);
}
}
/*
* There are two kinds of RX DMA interrupts(such as in the MX6Q):
* [1] the RX DMA buffer is full.
* [2] the aging timer expires
*
* Condition [2] is triggered when a character has been sitting in the FIFO
* for at least 8 byte durations.
*/
static void imx_uart_dma_rx_callback(void *data)
{
struct imx_port *sport = data;
struct dma_chan *chan = sport->dma_chan_rx;
struct scatterlist *sgl = &sport->rx_sgl;
struct tty_port *port = &sport->port.state->port;
struct dma_tx_state state;
struct circ_buf *rx_ring = &sport->rx_ring;
enum dma_status status;
unsigned int w_bytes = 0;
unsigned int r_bytes;
unsigned int bd_size;
status = dmaengine_tx_status(chan, sport->rx_cookie, &state);
if (status == DMA_ERROR) {
uart_port_lock(&sport->port);
imx_uart_clear_rx_errors(sport);
uart_port_unlock(&sport->port);
return;
}
/*
* The state-residue variable represents the empty space
* relative to the entire buffer. Taking this in consideration
* the head is always calculated base on the buffer total
* length - DMA transaction residue. The UART script from the
* SDMA firmware will jump to the next buffer descriptor,
* once a DMA transaction if finalized (IMX53 RM - A.4.1.2.4).
* Taking this in consideration the tail is always at the
* beginning of the buffer descriptor that contains the head.
*/
/* Calculate the head */
rx_ring->head = sg_dma_len(sgl) - state.residue;
/* Calculate the tail. */
bd_size = sg_dma_len(sgl) / sport->rx_periods;
rx_ring->tail = ((rx_ring->head-1) / bd_size) * bd_size;
if (rx_ring->head <= sg_dma_len(sgl) &&
rx_ring->head > rx_ring->tail) {
/* Move data from tail to head */
r_bytes = rx_ring->head - rx_ring->tail;
/* If we received something, check for 0xff flood */
uart_port_lock(&sport->port);
imx_uart_check_flood(sport, imx_uart_readl(sport, USR2));
uart_port_unlock(&sport->port);
if (!(sport->port.ignore_status_mask & URXD_DUMMY_READ)) {
/* CPU claims ownership of RX DMA buffer */
dma_sync_sg_for_cpu(sport->port.dev, sgl, 1,
DMA_FROM_DEVICE);
w_bytes = tty_insert_flip_string(port,
sport->rx_buf + rx_ring->tail, r_bytes);
/* UART retrieves ownership of RX DMA buffer */
dma_sync_sg_for_device(sport->port.dev, sgl, 1,
DMA_FROM_DEVICE);
if (w_bytes != r_bytes)
sport->port.icount.buf_overrun++;
sport->port.icount.rx += w_bytes;
}
} else {
WARN_ON(rx_ring->head > sg_dma_len(sgl));
WARN_ON(rx_ring->head <= rx_ring->tail);
}
if (w_bytes) {
tty_flip_buffer_push(port);
dev_dbg(sport->port.dev, "We get %d bytes.\n", w_bytes);
}
}
static int imx_uart_start_rx_dma(struct imx_port *sport)
{
struct scatterlist *sgl = &sport->rx_sgl;
struct dma_chan *chan = sport->dma_chan_rx;
struct device *dev = sport->port.dev;
struct dma_async_tx_descriptor *desc;
int ret;
sport->rx_ring.head = 0;
sport->rx_ring.tail = 0;
sg_init_one(sgl, sport->rx_buf, sport->rx_buf_size);
ret = dma_map_sg(dev, sgl, 1, DMA_FROM_DEVICE);
if (ret == 0) {
dev_err(dev, "DMA mapping error for RX.\n");
return -EINVAL;
}
desc = dmaengine_prep_dma_cyclic(chan, sg_dma_address(sgl),
sg_dma_len(sgl), sg_dma_len(sgl) / sport->rx_periods,
DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT);
if (!desc) {
dma_unmap_sg(dev, sgl, 1, DMA_FROM_DEVICE);
dev_err(dev, "We cannot prepare for the RX slave dma!\n");
return -EINVAL;
}
desc->callback = imx_uart_dma_rx_callback;
desc->callback_param = sport;
dev_dbg(dev, "RX: prepare for the DMA.\n");
sport->dma_is_rxing = 1;
sport->rx_cookie = dmaengine_submit(desc);
dma_async_issue_pending(chan);
return 0;
}
static void imx_uart_clear_rx_errors(struct imx_port *sport)
{
struct tty_port *port = &sport->port.state->port;
u32 usr1, usr2;
usr1 = imx_uart_readl(sport, USR1);
usr2 = imx_uart_readl(sport, USR2);
if (usr2 & USR2_BRCD) {
sport->port.icount.brk++;
imx_uart_writel(sport, USR2_BRCD, USR2);
uart_handle_break(&sport->port);
if (tty_insert_flip_char(port, 0, TTY_BREAK) == 0)
sport->port.icount.buf_overrun++;
tty_flip_buffer_push(port);
} else {
if (usr1 & USR1_FRAMERR) {
sport->port.icount.frame++;
imx_uart_writel(sport, USR1_FRAMERR, USR1);
} else if (usr1 & USR1_PARITYERR) {
sport->port.icount.parity++;
imx_uart_writel(sport, USR1_PARITYERR, USR1);
}
}
if (usr2 & USR2_ORE) {
sport->port.icount.overrun++;
imx_uart_writel(sport, USR2_ORE, USR2);
}
sport->idle_counter = 0;
}
#define TXTL_DEFAULT 8
#define RXTL_DEFAULT 8 /* 8 characters or aging timer */
#define TXTL_DMA 8 /* DMA burst setting */
#define RXTL_DMA 9 /* DMA burst setting */
static void imx_uart_setup_ufcr(struct imx_port *sport,
unsigned char txwl, unsigned char rxwl)
{
unsigned int val;
/* set receiver / transmitter trigger level */
val = imx_uart_readl(sport, UFCR) & (UFCR_RFDIV | UFCR_DCEDTE);
val |= txwl << UFCR_TXTL_SHF | rxwl;
imx_uart_writel(sport, val, UFCR);
}
static void imx_uart_dma_exit(struct imx_port *sport)
{
if (sport->dma_chan_rx) {
dmaengine_terminate_sync(sport->dma_chan_rx);
dma_release_channel(sport->dma_chan_rx);
sport->dma_chan_rx = NULL;
sport->rx_cookie = -EINVAL;
kfree(sport->rx_buf);
sport->rx_buf = NULL;
}
if (sport->dma_chan_tx) {
dmaengine_terminate_sync(sport->dma_chan_tx);
dma_release_channel(sport->dma_chan_tx);
sport->dma_chan_tx = NULL;
}
}
static int imx_uart_dma_init(struct imx_port *sport)
{
struct dma_slave_config slave_config = {};
struct device *dev = sport->port.dev;
struct dma_chan *chan;
int ret;
/* Prepare for RX : */
chan = dma_request_chan(dev, "rx");
if (IS_ERR(chan)) {
dev_dbg(dev, "cannot get the DMA channel.\n");
sport->dma_chan_rx = NULL;
ret = PTR_ERR(chan);
goto err;
}
sport->dma_chan_rx = chan;
slave_config.direction = DMA_DEV_TO_MEM;
slave_config.src_addr = sport->port.mapbase + URXD0;
slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
/* one byte less than the watermark level to enable the aging timer */
slave_config.src_maxburst = RXTL_DMA - 1;
ret = dmaengine_slave_config(sport->dma_chan_rx, &slave_config);
if (ret) {
dev_err(dev, "error in RX dma configuration.\n");
goto err;
}
sport->rx_buf_size = sport->rx_period_length * sport->rx_periods;
sport->rx_buf = kzalloc(sport->rx_buf_size, GFP_KERNEL);
if (!sport->rx_buf) {
ret = -ENOMEM;
goto err;
}
sport->rx_ring.buf = sport->rx_buf;
/* Prepare for TX : */
chan = dma_request_chan(dev, "tx");
if (IS_ERR(chan)) {
dev_err(dev, "cannot get the TX DMA channel!\n");
sport->dma_chan_tx = NULL;
ret = PTR_ERR(chan);
goto err;
}
sport->dma_chan_tx = chan;
slave_config.direction = DMA_MEM_TO_DEV;
slave_config.dst_addr = sport->port.mapbase + URTX0;
slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
slave_config.dst_maxburst = TXTL_DMA;
ret = dmaengine_slave_config(sport->dma_chan_tx, &slave_config);
if (ret) {
dev_err(dev, "error in TX dma configuration.");
goto err;
}
return 0;
err:
imx_uart_dma_exit(sport);
return ret;
}
static void imx_uart_enable_dma(struct imx_port *sport)
{
u32 ucr1;
imx_uart_setup_ufcr(sport, TXTL_DMA, RXTL_DMA);
/* set UCR1 */
ucr1 = imx_uart_readl(sport, UCR1);
ucr1 |= UCR1_RXDMAEN | UCR1_TXDMAEN | UCR1_ATDMAEN;
imx_uart_writel(sport, ucr1, UCR1);
sport->dma_is_enabled = 1;
}
static void imx_uart_disable_dma(struct imx_port *sport)
{
u32 ucr1;
/* clear UCR1 */
ucr1 = imx_uart_readl(sport, UCR1);
ucr1 &= ~(UCR1_RXDMAEN | UCR1_TXDMAEN | UCR1_ATDMAEN);
imx_uart_writel(sport, ucr1, UCR1);
imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT);
sport->dma_is_enabled = 0;
}
/* half the RX buffer size */
#define CTSTL 16
static int imx_uart_startup(struct uart_port *port)
{
struct imx_port *sport = to_imx_port(port);
int retval;
unsigned long flags;
int dma_is_inited = 0;
u32 ucr1, ucr2, ucr3, ucr4;
retval = clk_prepare_enable(sport->clk_per);
if (retval)
return retval;
retval = clk_prepare_enable(sport->clk_ipg);
if (retval) {
clk_disable_unprepare(sport->clk_per);
return retval;
}
imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT);
/* disable the DREN bit (Data Ready interrupt enable) before
* requesting IRQs
*/
ucr4 = imx_uart_readl(sport, UCR4);
/* set the trigger level for CTS */
ucr4 &= ~(UCR4_CTSTL_MASK << UCR4_CTSTL_SHF);
ucr4 |= CTSTL << UCR4_CTSTL_SHF;
imx_uart_writel(sport, ucr4 & ~UCR4_DREN, UCR4);
/* Can we enable the DMA support? */
if (!uart_console(port) && imx_uart_dma_init(sport) == 0) {
lockdep_set_subclass(&port->lock, 1);
dma_is_inited = 1;
}
uart_port_lock_irqsave(&sport->port, &flags);
/* Reset fifo's and state machines */
imx_uart_soft_reset(sport);
/*
* Finally, clear and enable interrupts
*/
imx_uart_writel(sport, USR1_RTSD | USR1_DTRD, USR1);
imx_uart_writel(sport, USR2_ORE, USR2);
ucr1 = imx_uart_readl(sport, UCR1) & ~UCR1_RRDYEN;
ucr1 |= UCR1_UARTEN;
if (sport->have_rtscts)
ucr1 |= UCR1_RTSDEN;
imx_uart_writel(sport, ucr1, UCR1);
ucr4 = imx_uart_readl(sport, UCR4) & ~(UCR4_OREN | UCR4_INVR);
if (!dma_is_inited)
ucr4 |= UCR4_OREN;
if (sport->inverted_rx)
ucr4 |= UCR4_INVR;
imx_uart_writel(sport, ucr4, UCR4);
ucr3 = imx_uart_readl(sport, UCR3) & ~UCR3_INVT;
/*
* configure tx polarity before enabling tx
*/
if (sport->inverted_tx)
ucr3 |= UCR3_INVT;
if (!imx_uart_is_imx1(sport)) {
ucr3 |= UCR3_DTRDEN | UCR3_RI | UCR3_DCD;
if (sport->dte_mode)
/* disable broken interrupts */
ucr3 &= ~(UCR3_RI | UCR3_DCD);
}
imx_uart_writel(sport, ucr3, UCR3);
ucr2 = imx_uart_readl(sport, UCR2) & ~UCR2_ATEN;
ucr2 |= (UCR2_RXEN | UCR2_TXEN);
if (!sport->have_rtscts)
ucr2 |= UCR2_IRTS;
/*
* make sure the edge sensitive RTS-irq is disabled,
* we're using RTSD instead.
*/
if (!imx_uart_is_imx1(sport))
ucr2 &= ~UCR2_RTSEN;
imx_uart_writel(sport, ucr2, UCR2);
/*
* Enable modem status interrupts
*/
imx_uart_enable_ms(&sport->port);
if (dma_is_inited) {
imx_uart_enable_dma(sport);
imx_uart_start_rx_dma(sport);
} else {
ucr1 = imx_uart_readl(sport, UCR1);
ucr1 |= UCR1_RRDYEN;
imx_uart_writel(sport, ucr1, UCR1);
ucr2 = imx_uart_readl(sport, UCR2);
ucr2 |= UCR2_ATEN;
imx_uart_writel(sport, ucr2, UCR2);
}
imx_uart_disable_loopback_rs485(sport);
uart_port_unlock_irqrestore(&sport->port, flags);
return 0;
}
static void imx_uart_shutdown(struct uart_port *port)
{
struct imx_port *sport = to_imx_port(port);
unsigned long flags;
u32 ucr1, ucr2, ucr4, uts;
int loops;
if (sport->dma_is_enabled) {
dmaengine_terminate_sync(sport->dma_chan_tx);
if (sport->dma_is_txing) {
dma_unmap_sg(sport->port.dev, &sport->tx_sgl[0],
sport->dma_tx_nents, DMA_TO_DEVICE);
sport->dma_is_txing = 0;
}
dmaengine_terminate_sync(sport->dma_chan_rx);
if (sport->dma_is_rxing) {
dma_unmap_sg(sport->port.dev, &sport->rx_sgl,
1, DMA_FROM_DEVICE);
sport->dma_is_rxing = 0;
}
uart_port_lock_irqsave(&sport->port, &flags);
imx_uart_stop_tx(port);
imx_uart_stop_rx(port);
imx_uart_disable_dma(sport);
uart_port_unlock_irqrestore(&sport->port, flags);
imx_uart_dma_exit(sport);
}
mctrl_gpio_disable_ms(sport->gpios);
uart_port_lock_irqsave(&sport->port, &flags);
ucr2 = imx_uart_readl(sport, UCR2);
ucr2 &= ~(UCR2_TXEN | UCR2_ATEN);
imx_uart_writel(sport, ucr2, UCR2);
uart_port_unlock_irqrestore(&sport->port, flags);
/*
* Stop our timer.
*/
del_timer_sync(&sport->timer);
/*
* Disable all interrupts, port and break condition.
*/
uart_port_lock_irqsave(&sport->port, &flags);
ucr1 = imx_uart_readl(sport, UCR1);
ucr1 &= ~(UCR1_TRDYEN | UCR1_RRDYEN | UCR1_RTSDEN | UCR1_RXDMAEN |
UCR1_ATDMAEN | UCR1_SNDBRK);
/* See SER_RS485_ENABLED/UTS_LOOP comment in imx_uart_probe() */
if (port->rs485.flags & SER_RS485_ENABLED &&
port->rs485.flags & SER_RS485_RTS_ON_SEND &&
sport->have_rtscts && !sport->have_rtsgpio) {
uts = imx_uart_readl(sport, imx_uart_uts_reg(sport));
uts |= UTS_LOOP;
imx_uart_writel(sport, uts, imx_uart_uts_reg(sport));
ucr1 |= UCR1_UARTEN;
} else {
ucr1 &= ~UCR1_UARTEN;
}
imx_uart_writel(sport, ucr1, UCR1);
ucr4 = imx_uart_readl(sport, UCR4);
ucr4 &= ~UCR4_TCEN;
imx_uart_writel(sport, ucr4, UCR4);
/*
* We have to ensure the tx state machine ends up in OFF. This
* is especially important for rs485 where we must not leave
* the RTS signal high, blocking the bus indefinitely.
*
* All interrupts are now disabled, so imx_uart_stop_tx() will
* no longer be called from imx_uart_transmit_buffer(). It may
* still be called via the hrtimers, and if those are in play,
* we have to honour the delays.
*/
if (sport->tx_state == WAIT_AFTER_RTS || sport->tx_state == SEND)
imx_uart_stop_tx(port);
/*
* In many cases (rs232 mode, or if tx_state was
* WAIT_AFTER_RTS, or if tx_state was SEND and there is no
* delay_rts_after_send), this will have moved directly to
* OFF. In rs485 mode, tx_state might already have been
* WAIT_AFTER_SEND and the hrtimer thus already started, or
* the above imx_uart_stop_tx() call could have started it. In
* those cases, we have to wait for the hrtimer to fire and
* complete the transition to OFF.
*/
loops = port->rs485.flags & SER_RS485_ENABLED ?
port->rs485.delay_rts_after_send : 0;
while (sport->tx_state != OFF && loops--) {
uart_port_unlock_irqrestore(&sport->port, flags);
msleep(1);
uart_port_lock_irqsave(&sport->port, &flags);
}
if (sport->tx_state != OFF) {
dev_warn(sport->port.dev, "unexpected tx_state %d\n",
sport->tx_state);
/*
* This machine may be busted, but ensure the RTS
* signal is inactive in order not to block other
* devices.
*/
if (port->rs485.flags & SER_RS485_ENABLED) {
ucr2 = imx_uart_readl(sport, UCR2);
if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND)
imx_uart_rts_active(sport, &ucr2);
else
imx_uart_rts_inactive(sport, &ucr2);
imx_uart_writel(sport, ucr2, UCR2);
}
sport->tx_state = OFF;
}
uart_port_unlock_irqrestore(&sport->port, flags);
clk_disable_unprepare(sport->clk_per);
clk_disable_unprepare(sport->clk_ipg);
}
/* called with port.lock taken and irqs off */
static void imx_uart_flush_buffer(struct uart_port *port)
{
struct imx_port *sport = to_imx_port(port);
struct scatterlist *sgl = &sport->tx_sgl[0];
if (!sport->dma_chan_tx)
return;
sport->tx_bytes = 0;
dmaengine_terminate_all(sport->dma_chan_tx);
if (sport->dma_is_txing) {
u32 ucr1;
dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents,
DMA_TO_DEVICE);
ucr1 = imx_uart_readl(sport, UCR1);
ucr1 &= ~UCR1_TXDMAEN;
imx_uart_writel(sport, ucr1, UCR1);
sport->dma_is_txing = 0;
}
imx_uart_soft_reset(sport);
}
static void
imx_uart_set_termios(struct uart_port *port, struct ktermios *termios,
const struct ktermios *old)
{
struct imx_port *sport = to_imx_port(port);
unsigned long flags;
u32 ucr2, old_ucr2, ufcr;
unsigned int baud, quot;
unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;
unsigned long div;
unsigned long num, denom, old_ubir, old_ubmr;
uint64_t tdiv64;
/*
* We only support CS7 and CS8.
*/
while ((termios->c_cflag & CSIZE) != CS7 &&
(termios->c_cflag & CSIZE) != CS8) {
termios->c_cflag &= ~CSIZE;
termios->c_cflag |= old_csize;
old_csize = CS8;
}
del_timer_sync(&sport->timer);
/*
* Ask the core to calculate the divisor for us.
*/
baud = uart_get_baud_rate(port, termios, old, 50, port->uartclk / 16);
quot = uart_get_divisor(port, baud);
uart_port_lock_irqsave(&sport->port, &flags);
/*
* Read current UCR2 and save it for future use, then clear all the bits
* except those we will or may need to preserve.
*/
old_ucr2 = imx_uart_readl(sport, UCR2);
ucr2 = old_ucr2 & (UCR2_TXEN | UCR2_RXEN | UCR2_ATEN | UCR2_CTS);
ucr2 |= UCR2_SRST | UCR2_IRTS;
if ((termios->c_cflag & CSIZE) == CS8)
ucr2 |= UCR2_WS;
if (!sport->have_rtscts)
termios->c_cflag &= ~CRTSCTS;
if (port->rs485.flags & SER_RS485_ENABLED) {
/*
* RTS is mandatory for rs485 operation, so keep
* it under manual control and keep transmitter
* disabled.
*/
if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND)
imx_uart_rts_active(sport, &ucr2);
else
imx_uart_rts_inactive(sport, &ucr2);
} else if (termios->c_cflag & CRTSCTS) {
/*
* Only let receiver control RTS output if we were not requested
* to have RTS inactive (which then should take precedence).
*/
if (ucr2 & UCR2_CTS)
ucr2 |= UCR2_CTSC;
}
if (termios->c_cflag & CRTSCTS)
ucr2 &= ~UCR2_IRTS;
if (termios->c_cflag & CSTOPB)
ucr2 |= UCR2_STPB;
if (termios->c_cflag & PARENB) {
ucr2 |= UCR2_PREN;
if (termios->c_cflag & PARODD)
ucr2 |= UCR2_PROE;
}
sport->port.read_status_mask = 0;
if (termios->c_iflag & INPCK)
sport->port.read_status_mask |= (URXD_FRMERR | URXD_PRERR);
if (termios->c_iflag & (BRKINT | PARMRK))
sport->port.read_status_mask |= URXD_BRK;
/*
* Characters to ignore
*/
sport->port.ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
sport->port.ignore_status_mask |= URXD_PRERR | URXD_FRMERR;
if (termios->c_iflag & IGNBRK) {
sport->port.ignore_status_mask |= URXD_BRK;
/*
* If we're ignoring parity and break indicators,
* ignore overruns too (for real raw support).
*/
if (termios->c_iflag & IGNPAR)
sport->port.ignore_status_mask |= URXD_OVRRUN;
}
if ((termios->c_cflag & CREAD) == 0)
sport->port.ignore_status_mask |= URXD_DUMMY_READ;
/*
* Update the per-port timeout.
*/
uart_update_timeout(port, termios->c_cflag, baud);
/* custom-baudrate handling */
div = sport->port.uartclk / (baud * 16);
if (baud == 38400 && quot != div)
baud = sport->port.uartclk / (quot * 16);
div = sport->port.uartclk / (baud * 16);
if (div > 7)
div = 7;
if (!div)
div = 1;
rational_best_approximation(16 * div * baud, sport->port.uartclk,
1 << 16, 1 << 16, &num, &denom);
tdiv64 = sport->port.uartclk;
tdiv64 *= num;
do_div(tdiv64, denom * 16 * div);
tty_termios_encode_baud_rate(termios,
(speed_t)tdiv64, (speed_t)tdiv64);
num -= 1;
denom -= 1;
ufcr = imx_uart_readl(sport, UFCR);
ufcr = (ufcr & (~UFCR_RFDIV)) | UFCR_RFDIV_REG(div);
imx_uart_writel(sport, ufcr, UFCR);
/*
* Two registers below should always be written both and in this
* particular order. One consequence is that we need to check if any of
* them changes and then update both. We do need the check for change
* as even writing the same values seem to "restart"
* transmission/receiving logic in the hardware, that leads to data
* breakage even when rate doesn't in fact change. E.g., user switches
* RTS/CTS handshake and suddenly gets broken bytes.
*/
old_ubir = imx_uart_readl(sport, UBIR);
old_ubmr = imx_uart_readl(sport, UBMR);
if (old_ubir != num || old_ubmr != denom) {
imx_uart_writel(sport, num, UBIR);
imx_uart_writel(sport, denom, UBMR);
}
if (!imx_uart_is_imx1(sport))
imx_uart_writel(sport, sport->port.uartclk / div / 1000,
IMX21_ONEMS);
imx_uart_writel(sport, ucr2, UCR2);
if (UART_ENABLE_MS(&sport->port, termios->c_cflag))
imx_uart_enable_ms(&sport->port);
uart_port_unlock_irqrestore(&sport->port, flags);
}
static const char *imx_uart_type(struct uart_port *port)
{
return port->type == PORT_IMX ? "IMX" : NULL;
}
/*
* Configure/autoconfigure the port.
*/
static void imx_uart_config_port(struct uart_port *port, int flags)
{
if (flags & UART_CONFIG_TYPE)
port->type = PORT_IMX;
}
/*
* Verify the new serial_struct (for TIOCSSERIAL).
* The only change we allow are to the flags and type, and
* even then only between PORT_IMX and PORT_UNKNOWN
*/
static int
imx_uart_verify_port(struct uart_port *port, struct serial_struct *ser)
{
int ret = 0;
if (ser->type != PORT_UNKNOWN && ser->type != PORT_IMX)
ret = -EINVAL;
if (port->irq != ser->irq)
ret = -EINVAL;
if (ser->io_type != UPIO_MEM)
ret = -EINVAL;
if (port->uartclk / 16 != ser->baud_base)
ret = -EINVAL;
if (port->mapbase != (unsigned long)ser->iomem_base)
ret = -EINVAL;
if (port->iobase != ser->port)
ret = -EINVAL;
if (ser->hub6 != 0)
ret = -EINVAL;
return ret;
}
#if defined(CONFIG_CONSOLE_POLL)
static int imx_uart_poll_init(struct uart_port *port)
{
struct imx_port *sport = to_imx_port(port);
unsigned long flags;
u32 ucr1, ucr2;
int retval;
retval = clk_prepare_enable(sport->clk_ipg);
if (retval)
return retval;
retval = clk_prepare_enable(sport->clk_per);
if (retval)
clk_disable_unprepare(sport->clk_ipg);
imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT);
uart_port_lock_irqsave(&sport->port, &flags);
/*
* Be careful about the order of enabling bits here. First enable the
* receiver (UARTEN + RXEN) and only then the corresponding irqs.
* This prevents that a character that already sits in the RX fifo is
* triggering an irq but the try to fetch it from there results in an
* exception because UARTEN or RXEN is still off.
*/
ucr1 = imx_uart_readl(sport, UCR1);
ucr2 = imx_uart_readl(sport, UCR2);
if (imx_uart_is_imx1(sport))
ucr1 |= IMX1_UCR1_UARTCLKEN;
ucr1 |= UCR1_UARTEN;
ucr1 &= ~(UCR1_TRDYEN | UCR1_RTSDEN | UCR1_RRDYEN);
ucr2 |= UCR2_RXEN | UCR2_TXEN;
ucr2 &= ~UCR2_ATEN;
imx_uart_writel(sport, ucr1, UCR1);
imx_uart_writel(sport, ucr2, UCR2);
/* now enable irqs */
imx_uart_writel(sport, ucr1 | UCR1_RRDYEN, UCR1);
imx_uart_writel(sport, ucr2 | UCR2_ATEN, UCR2);
uart_port_unlock_irqrestore(&sport->port, flags);
return 0;
}
static int imx_uart_poll_get_char(struct uart_port *port)
{
struct imx_port *sport = to_imx_port(port);
if (!(imx_uart_readl(sport, USR2) & USR2_RDR))
return NO_POLL_CHAR;
return imx_uart_readl(sport, URXD0) & URXD_RX_DATA;
}
static void imx_uart_poll_put_char(struct uart_port *port, unsigned char c)
{
struct imx_port *sport = to_imx_port(port);
unsigned int status;
/* drain */
do {
status = imx_uart_readl(sport, USR1);
} while (~status & USR1_TRDY);
/* write */
imx_uart_writel(sport, c, URTX0);
/* flush */
do {
status = imx_uart_readl(sport, USR2);
} while (~status & USR2_TXDC);
}
#endif
/* called with port.lock taken and irqs off or from .probe without locking */
static int imx_uart_rs485_config(struct uart_port *port, struct ktermios *termios,
struct serial_rs485 *rs485conf)
{
struct imx_port *sport = to_imx_port(port);
u32 ucr2, ufcr;
if (rs485conf->flags & SER_RS485_ENABLED) {
/* Enable receiver if low-active RTS signal is requested */
if (sport->have_rtscts && !sport->have_rtsgpio &&
!(rs485conf->flags & SER_RS485_RTS_ON_SEND))
rs485conf->flags |= SER_RS485_RX_DURING_TX;
/* disable transmitter */
ucr2 = imx_uart_readl(sport, UCR2);
if (rs485conf->flags & SER_RS485_RTS_AFTER_SEND)
imx_uart_rts_active(sport, &ucr2);
else
imx_uart_rts_inactive(sport, &ucr2);
imx_uart_writel(sport, ucr2, UCR2);
}
/* Make sure Rx is enabled in case Tx is active with Rx disabled */
if (!(rs485conf->flags & SER_RS485_ENABLED) ||
rs485conf->flags & SER_RS485_RX_DURING_TX) {
/* If the receiver trigger is 0, set it to a default value */
ufcr = imx_uart_readl(sport, UFCR);
if ((ufcr & UFCR_RXTL_MASK) == 0)
imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT);
imx_uart_start_rx(port);
}
return 0;
}
static const struct uart_ops imx_uart_pops = {
.tx_empty = imx_uart_tx_empty,
.set_mctrl = imx_uart_set_mctrl,
.get_mctrl = imx_uart_get_mctrl,
.stop_tx = imx_uart_stop_tx,
.start_tx = imx_uart_start_tx,
.stop_rx = imx_uart_stop_rx,
.enable_ms = imx_uart_enable_ms,
.break_ctl = imx_uart_break_ctl,
.startup = imx_uart_startup,
.shutdown = imx_uart_shutdown,
.flush_buffer = imx_uart_flush_buffer,
.set_termios = imx_uart_set_termios,
.type = imx_uart_type,
.config_port = imx_uart_config_port,
.verify_port = imx_uart_verify_port,
#if defined(CONFIG_CONSOLE_POLL)
.poll_init = imx_uart_poll_init,
.poll_get_char = imx_uart_poll_get_char,
.poll_put_char = imx_uart_poll_put_char,
#endif
};
static struct imx_port *imx_uart_ports[UART_NR];
#if IS_ENABLED(CONFIG_SERIAL_IMX_CONSOLE)
static void imx_uart_console_putchar(struct uart_port *port, unsigned char ch)
{
struct imx_port *sport = to_imx_port(port);
while (imx_uart_readl(sport, imx_uart_uts_reg(sport)) & UTS_TXFULL)
barrier();
imx_uart_writel(sport, ch, URTX0);
}
/*
* Interrupts are disabled on entering
*/
static void
imx_uart_console_write(struct console *co, const char *s, unsigned int count)
{
struct imx_port *sport = imx_uart_ports[co->index];
struct imx_port_ucrs old_ucr;
unsigned long flags;
unsigned int ucr1, usr2;
int locked = 1;
if (sport->port.sysrq)
locked = 0;
else if (oops_in_progress)
locked = uart_port_trylock_irqsave(&sport->port, &flags);
else
uart_port_lock_irqsave(&sport->port, &flags);
/*
* First, save UCR1/2/3 and then disable interrupts
*/
imx_uart_ucrs_save(sport, &old_ucr);
ucr1 = old_ucr.ucr1;
if (imx_uart_is_imx1(sport))
ucr1 |= IMX1_UCR1_UARTCLKEN;
ucr1 |= UCR1_UARTEN;
ucr1 &= ~(UCR1_TRDYEN | UCR1_RRDYEN | UCR1_RTSDEN);
imx_uart_writel(sport, ucr1, UCR1);
imx_uart_writel(sport, old_ucr.ucr2 | UCR2_TXEN, UCR2);
uart_console_write(&sport->port, s, count, imx_uart_console_putchar);
/*
* Finally, wait for transmitter to become empty
* and restore UCR1/2/3
*/
read_poll_timeout_atomic(imx_uart_readl, usr2, usr2 & USR2_TXDC,
0, USEC_PER_SEC, false, sport, USR2);
imx_uart_ucrs_restore(sport, &old_ucr);
if (locked)
uart_port_unlock_irqrestore(&sport->port, flags);
}
/*
* If the port was already initialised (eg, by a boot loader),
* try to determine the current setup.
*/
static void
imx_uart_console_get_options(struct imx_port *sport, int *baud,
int *parity, int *bits)
{
if (imx_uart_readl(sport, UCR1) & UCR1_UARTEN) {
/* ok, the port was enabled */
unsigned int ucr2, ubir, ubmr, uartclk;
unsigned int baud_raw;
unsigned int ucfr_rfdiv;
ucr2 = imx_uart_readl(sport, UCR2);
*parity = 'n';
if (ucr2 & UCR2_PREN) {
if (ucr2 & UCR2_PROE)
*parity = 'o';
else
*parity = 'e';
}
if (ucr2 & UCR2_WS)
*bits = 8;
else
*bits = 7;
ubir = imx_uart_readl(sport, UBIR) & 0xffff;
ubmr = imx_uart_readl(sport, UBMR) & 0xffff;
ucfr_rfdiv = (imx_uart_readl(sport, UFCR) & UFCR_RFDIV) >> 7;
if (ucfr_rfdiv == 6)
ucfr_rfdiv = 7;
else
ucfr_rfdiv = 6 - ucfr_rfdiv;
uartclk = clk_get_rate(sport->clk_per);
uartclk /= ucfr_rfdiv;
{ /*
* The next code provides exact computation of
* baud_raw = round(((uartclk/16) * (ubir + 1)) / (ubmr + 1))
* without need of float support or long long division,
* which would be required to prevent 32bit arithmetic overflow
*/
unsigned int mul = ubir + 1;
unsigned int div = 16 * (ubmr + 1);
unsigned int rem = uartclk % div;
baud_raw = (uartclk / div) * mul;
baud_raw += (rem * mul + div / 2) / div;
*baud = (baud_raw + 50) / 100 * 100;
}
if (*baud != baud_raw)
dev_info(sport->port.dev, "Console IMX rounded baud rate from %d to %d\n",
baud_raw, *baud);
}
}
static int
imx_uart_console_setup(struct console *co, char *options)
{
struct imx_port *sport;
int baud = 9600;
int bits = 8;
int parity = 'n';
int flow = 'n';
int retval;
/*
* Check whether an invalid uart number has been specified, and
* if so, search for the first available port that does have
* console support.
*/
if (co->index == -1 || co->index >= ARRAY_SIZE(imx_uart_ports))
co->index = 0;
sport = imx_uart_ports[co->index];
if (sport == NULL)
return -ENODEV;
/* For setting the registers, we only need to enable the ipg clock. */
retval = clk_prepare_enable(sport->clk_ipg);
if (retval)
goto error_console;
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
else
imx_uart_console_get_options(sport, &baud, &parity, &bits);
imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT);
retval = uart_set_options(&sport->port, co, baud, parity, bits, flow);
if (retval) {
clk_disable_unprepare(sport->clk_ipg);
goto error_console;
}
retval = clk_prepare_enable(sport->clk_per);
if (retval)
clk_disable_unprepare(sport->clk_ipg);
error_console:
return retval;
}
static int
imx_uart_console_exit(struct console *co)
{
struct imx_port *sport = imx_uart_ports[co->index];
clk_disable_unprepare(sport->clk_per);
clk_disable_unprepare(sport->clk_ipg);
return 0;
}
static struct uart_driver imx_uart_uart_driver;
static struct console imx_uart_console = {
.name = DEV_NAME,
.write = imx_uart_console_write,
.device = uart_console_device,
.setup = imx_uart_console_setup,
.exit = imx_uart_console_exit,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &imx_uart_uart_driver,
};
#define IMX_CONSOLE &imx_uart_console
#else
#define IMX_CONSOLE NULL
#endif
static struct uart_driver imx_uart_uart_driver = {
.owner = THIS_MODULE,
.driver_name = DRIVER_NAME,
.dev_name = DEV_NAME,
.major = SERIAL_IMX_MAJOR,
.minor = MINOR_START,
.nr = ARRAY_SIZE(imx_uart_ports),
.cons = IMX_CONSOLE,
};
static enum hrtimer_restart imx_trigger_start_tx(struct hrtimer *t)
{
struct imx_port *sport = container_of(t, struct imx_port, trigger_start_tx);
unsigned long flags;
uart_port_lock_irqsave(&sport->port, &flags);
if (sport->tx_state == WAIT_AFTER_RTS)
imx_uart_start_tx(&sport->port);
uart_port_unlock_irqrestore(&sport->port, flags);
return HRTIMER_NORESTART;
}
static enum hrtimer_restart imx_trigger_stop_tx(struct hrtimer *t)
{
struct imx_port *sport = container_of(t, struct imx_port, trigger_stop_tx);
unsigned long flags;
uart_port_lock_irqsave(&sport->port, &flags);
if (sport->tx_state == WAIT_AFTER_SEND)
imx_uart_stop_tx(&sport->port);
uart_port_unlock_irqrestore(&sport->port, flags);
return HRTIMER_NORESTART;
}
static const struct serial_rs485 imx_rs485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND |
SER_RS485_RX_DURING_TX,
.delay_rts_before_send = 1,
.delay_rts_after_send = 1,
};
/* Default RX DMA buffer configuration */
#define RX_DMA_PERIODS 16
#define RX_DMA_PERIOD_LEN (PAGE_SIZE / 4)
static int imx_uart_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct imx_port *sport;
void __iomem *base;
u32 dma_buf_conf[2];
int ret = 0;
u32 ucr1, ucr2, uts;
struct resource *res;
int txirq, rxirq, rtsirq;
sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL);
if (!sport)
return -ENOMEM;
sport->devdata = of_device_get_match_data(&pdev->dev);
ret = of_alias_get_id(np, "serial");
if (ret < 0) {
dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
return ret;
}
sport->port.line = ret;
sport->have_rtscts = of_property_read_bool(np, "uart-has-rtscts") ||
of_property_read_bool(np, "fsl,uart-has-rtscts"); /* deprecated */
sport->dte_mode = of_property_read_bool(np, "fsl,dte-mode");
sport->have_rtsgpio = of_property_present(np, "rts-gpios");
sport->inverted_tx = of_property_read_bool(np, "fsl,inverted-tx");
sport->inverted_rx = of_property_read_bool(np, "fsl,inverted-rx");
if (!of_property_read_u32_array(np, "fsl,dma-info", dma_buf_conf, 2)) {
sport->rx_period_length = dma_buf_conf[0];
sport->rx_periods = dma_buf_conf[1];
} else {
sport->rx_period_length = RX_DMA_PERIOD_LEN;
sport->rx_periods = RX_DMA_PERIODS;
}
if (sport->port.line >= ARRAY_SIZE(imx_uart_ports)) {
dev_err(&pdev->dev, "serial%d out of range\n",
sport->port.line);
return -EINVAL;
}
base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
if (IS_ERR(base))
return PTR_ERR(base);
rxirq = platform_get_irq(pdev, 0);
if (rxirq < 0)
return rxirq;
txirq = platform_get_irq_optional(pdev, 1);
rtsirq = platform_get_irq_optional(pdev, 2);
sport->port.dev = &pdev->dev;
sport->port.mapbase = res->start;
sport->port.membase = base;
sport->port.type = PORT_IMX;
sport->port.iotype = UPIO_MEM;
sport->port.irq = rxirq;
sport->port.fifosize = 32;
sport->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_IMX_CONSOLE);
sport->port.ops = &imx_uart_pops;
sport->port.rs485_config = imx_uart_rs485_config;
/* RTS is required to control the RS485 transmitter */
if (sport->have_rtscts || sport->have_rtsgpio)
sport->port.rs485_supported = imx_rs485_supported;
sport->port.flags = UPF_BOOT_AUTOCONF;
timer_setup(&sport->timer, imx_uart_timeout, 0);
sport->gpios = mctrl_gpio_init(&sport->port, 0);
if (IS_ERR(sport->gpios))
return PTR_ERR(sport->gpios);
sport->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
if (IS_ERR(sport->clk_ipg)) {
ret = PTR_ERR(sport->clk_ipg);
dev_err(&pdev->dev, "failed to get ipg clk: %d\n", ret);
return ret;
}
sport->clk_per = devm_clk_get(&pdev->dev, "per");
if (IS_ERR(sport->clk_per)) {
ret = PTR_ERR(sport->clk_per);
dev_err(&pdev->dev, "failed to get per clk: %d\n", ret);
return ret;
}
sport->port.uartclk = clk_get_rate(sport->clk_per);
/* For register access, we only need to enable the ipg clock. */
ret = clk_prepare_enable(sport->clk_ipg);
if (ret) {
dev_err(&pdev->dev, "failed to enable ipg clk: %d\n", ret);
return ret;
}
ret = uart_get_rs485_mode(&sport->port);
if (ret)
goto err_clk;
/*
* If using the i.MX UART RTS/CTS control then the RTS (CTS_B)
* signal cannot be set low during transmission in case the
* receiver is off (limitation of the i.MX UART IP).
*/
if (sport->port.rs485.flags & SER_RS485_ENABLED &&
sport->have_rtscts && !sport->have_rtsgpio &&
(!(sport->port.rs485.flags & SER_RS485_RTS_ON_SEND) &&
!(sport->port.rs485.flags & SER_RS485_RX_DURING_TX)))
dev_err(&pdev->dev,
"low-active RTS not possible when receiver is off, enabling receiver\n");
/* Disable interrupts before requesting them */
ucr1 = imx_uart_readl(sport, UCR1);
ucr1 &= ~(UCR1_ADEN | UCR1_TRDYEN | UCR1_IDEN | UCR1_RRDYEN | UCR1_RTSDEN);
imx_uart_writel(sport, ucr1, UCR1);
/* Disable Ageing Timer interrupt */
ucr2 = imx_uart_readl(sport, UCR2);
ucr2 &= ~UCR2_ATEN;
imx_uart_writel(sport, ucr2, UCR2);
/*
* In case RS485 is enabled without GPIO RTS control, the UART IP
* is used to control CTS signal. Keep both the UART and Receiver
* enabled, otherwise the UART IP pulls CTS signal always HIGH no
* matter how the UCR2 CTSC and CTS bits are set. To prevent any
* data from being fed into the RX FIFO, enable loopback mode in
* UTS register, which disconnects the RX path from external RXD
* pin and connects it to the Transceiver, which is disabled, so
* no data can be fed to the RX FIFO that way.
*/
if (sport->port.rs485.flags & SER_RS485_ENABLED &&
sport->have_rtscts && !sport->have_rtsgpio) {
uts = imx_uart_readl(sport, imx_uart_uts_reg(sport));
uts |= UTS_LOOP;
imx_uart_writel(sport, uts, imx_uart_uts_reg(sport));
ucr1 = imx_uart_readl(sport, UCR1);
ucr1 |= UCR1_UARTEN;
imx_uart_writel(sport, ucr1, UCR1);
ucr2 = imx_uart_readl(sport, UCR2);
ucr2 |= UCR2_RXEN;
imx_uart_writel(sport, ucr2, UCR2);
}
if (!imx_uart_is_imx1(sport) && sport->dte_mode) {
/*
* The DCEDTE bit changes the direction of DSR, DCD, DTR and RI
* and influences if UCR3_RI and UCR3_DCD changes the level of RI
* and DCD (when they are outputs) or enables the respective
* irqs. So set this bit early, i.e. before requesting irqs.
*/
u32 ufcr = imx_uart_readl(sport, UFCR);
if (!(ufcr & UFCR_DCEDTE))
imx_uart_writel(sport, ufcr | UFCR_DCEDTE, UFCR);
/*
* Disable UCR3_RI and UCR3_DCD irqs. They are also not
* enabled later because they cannot be cleared
* (confirmed on i.MX25) which makes them unusable.
*/
imx_uart_writel(sport,
IMX21_UCR3_RXDMUXSEL | UCR3_ADNIMP | UCR3_DSR,
UCR3);
} else {
u32 ucr3 = UCR3_DSR;
u32 ufcr = imx_uart_readl(sport, UFCR);
if (ufcr & UFCR_DCEDTE)
imx_uart_writel(sport, ufcr & ~UFCR_DCEDTE, UFCR);
if (!imx_uart_is_imx1(sport))
ucr3 |= IMX21_UCR3_RXDMUXSEL | UCR3_ADNIMP;
imx_uart_writel(sport, ucr3, UCR3);
}
hrtimer_init(&sport->trigger_start_tx, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
hrtimer_init(&sport->trigger_stop_tx, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
sport->trigger_start_tx.function = imx_trigger_start_tx;
sport->trigger_stop_tx.function = imx_trigger_stop_tx;
/*
* Allocate the IRQ(s) i.MX1 has three interrupts whereas later
* chips only have one interrupt.
*/
if (txirq > 0) {
ret = devm_request_irq(&pdev->dev, rxirq, imx_uart_rxint, 0,
dev_name(&pdev->dev), sport);
if (ret) {
dev_err(&pdev->dev, "failed to request rx irq: %d\n",
ret);
goto err_clk;
}
ret = devm_request_irq(&pdev->dev, txirq, imx_uart_txint, 0,
dev_name(&pdev->dev), sport);
if (ret) {
dev_err(&pdev->dev, "failed to request tx irq: %d\n",
ret);
goto err_clk;
}
ret = devm_request_irq(&pdev->dev, rtsirq, imx_uart_rtsint, 0,
dev_name(&pdev->dev), sport);
if (ret) {
dev_err(&pdev->dev, "failed to request rts irq: %d\n",
ret);
goto err_clk;
}
} else {
ret = devm_request_irq(&pdev->dev, rxirq, imx_uart_int, 0,
dev_name(&pdev->dev), sport);
if (ret) {
dev_err(&pdev->dev, "failed to request irq: %d\n", ret);
goto err_clk;
}
}
imx_uart_ports[sport->port.line] = sport;
platform_set_drvdata(pdev, sport);
ret = uart_add_one_port(&imx_uart_uart_driver, &sport->port);
err_clk:
clk_disable_unprepare(sport->clk_ipg);
return ret;
}
static void imx_uart_remove(struct platform_device *pdev)
{
struct imx_port *sport = platform_get_drvdata(pdev);
uart_remove_one_port(&imx_uart_uart_driver, &sport->port);
}
static void imx_uart_restore_context(struct imx_port *sport)
{
unsigned long flags;
uart_port_lock_irqsave(&sport->port, &flags);
if (!sport->context_saved) {
uart_port_unlock_irqrestore(&sport->port, flags);
return;
}
imx_uart_writel(sport, sport->saved_reg[4], UFCR);
imx_uart_writel(sport, sport->saved_reg[5], UESC);
imx_uart_writel(sport, sport->saved_reg[6], UTIM);
imx_uart_writel(sport, sport->saved_reg[7], UBIR);
imx_uart_writel(sport, sport->saved_reg[8], UBMR);
imx_uart_writel(sport, sport->saved_reg[9], IMX21_UTS);
imx_uart_writel(sport, sport->saved_reg[0], UCR1);
imx_uart_writel(sport, sport->saved_reg[1] | UCR2_SRST, UCR2);
imx_uart_writel(sport, sport->saved_reg[2], UCR3);
imx_uart_writel(sport, sport->saved_reg[3], UCR4);
sport->context_saved = false;
uart_port_unlock_irqrestore(&sport->port, flags);
}
static void imx_uart_save_context(struct imx_port *sport)
{
unsigned long flags;
/* Save necessary regs */
uart_port_lock_irqsave(&sport->port, &flags);
sport->saved_reg[0] = imx_uart_readl(sport, UCR1);
sport->saved_reg[1] = imx_uart_readl(sport, UCR2);
sport->saved_reg[2] = imx_uart_readl(sport, UCR3);
sport->saved_reg[3] = imx_uart_readl(sport, UCR4);
sport->saved_reg[4] = imx_uart_readl(sport, UFCR);
sport->saved_reg[5] = imx_uart_readl(sport, UESC);
sport->saved_reg[6] = imx_uart_readl(sport, UTIM);
sport->saved_reg[7] = imx_uart_readl(sport, UBIR);
sport->saved_reg[8] = imx_uart_readl(sport, UBMR);
sport->saved_reg[9] = imx_uart_readl(sport, IMX21_UTS);
sport->context_saved = true;
uart_port_unlock_irqrestore(&sport->port, flags);
}
static void imx_uart_enable_wakeup(struct imx_port *sport, bool on)
{
u32 ucr3;
ucr3 = imx_uart_readl(sport, UCR3);
if (on) {
imx_uart_writel(sport, USR1_AWAKE, USR1);
ucr3 |= UCR3_AWAKEN;
} else {
ucr3 &= ~UCR3_AWAKEN;
}
imx_uart_writel(sport, ucr3, UCR3);
if (sport->have_rtscts) {
u32 ucr1 = imx_uart_readl(sport, UCR1);
if (on) {
imx_uart_writel(sport, USR1_RTSD, USR1);
ucr1 |= UCR1_RTSDEN;
} else {
ucr1 &= ~UCR1_RTSDEN;
}
imx_uart_writel(sport, ucr1, UCR1);
}
}
static int imx_uart_suspend_noirq(struct device *dev)
{
struct imx_port *sport = dev_get_drvdata(dev);
imx_uart_save_context(sport);
clk_disable(sport->clk_ipg);
pinctrl_pm_select_sleep_state(dev);
return 0;
}
static int imx_uart_resume_noirq(struct device *dev)
{
struct imx_port *sport = dev_get_drvdata(dev);
int ret;
pinctrl_pm_select_default_state(dev);
ret = clk_enable(sport->clk_ipg);
if (ret)
return ret;
imx_uart_restore_context(sport);
return 0;
}
static int imx_uart_suspend(struct device *dev)
{
struct imx_port *sport = dev_get_drvdata(dev);
int ret;
uart_suspend_port(&imx_uart_uart_driver, &sport->port);
disable_irq(sport->port.irq);
ret = clk_prepare_enable(sport->clk_ipg);
if (ret)
return ret;
/* enable wakeup from i.MX UART */
imx_uart_enable_wakeup(sport, true);
return 0;
}
static int imx_uart_resume(struct device *dev)
{
struct imx_port *sport = dev_get_drvdata(dev);
/* disable wakeup from i.MX UART */
imx_uart_enable_wakeup(sport, false);
uart_resume_port(&imx_uart_uart_driver, &sport->port);
enable_irq(sport->port.irq);
clk_disable_unprepare(sport->clk_ipg);
return 0;
}
static int imx_uart_freeze(struct device *dev)
{
struct imx_port *sport = dev_get_drvdata(dev);
uart_suspend_port(&imx_uart_uart_driver, &sport->port);
return clk_prepare_enable(sport->clk_ipg);
}
static int imx_uart_thaw(struct device *dev)
{
struct imx_port *sport = dev_get_drvdata(dev);
uart_resume_port(&imx_uart_uart_driver, &sport->port);
clk_disable_unprepare(sport->clk_ipg);
return 0;
}
static const struct dev_pm_ops imx_uart_pm_ops = {
.suspend_noirq = imx_uart_suspend_noirq,
.resume_noirq = imx_uart_resume_noirq,
.freeze_noirq = imx_uart_suspend_noirq,
.thaw_noirq = imx_uart_resume_noirq,
.restore_noirq = imx_uart_resume_noirq,
.suspend = imx_uart_suspend,
.resume = imx_uart_resume,
.freeze = imx_uart_freeze,
.thaw = imx_uart_thaw,
.restore = imx_uart_thaw,
};
static struct platform_driver imx_uart_platform_driver = {
.probe = imx_uart_probe,
.remove_new = imx_uart_remove,
.driver = {
.name = "imx-uart",
.of_match_table = imx_uart_dt_ids,
.pm = &imx_uart_pm_ops,
},
};
static int __init imx_uart_init(void)
{
int ret = uart_register_driver(&imx_uart_uart_driver);
if (ret)
return ret;
ret = platform_driver_register(&imx_uart_platform_driver);
if (ret != 0)
uart_unregister_driver(&imx_uart_uart_driver);
return ret;
}
static void __exit imx_uart_exit(void)
{
platform_driver_unregister(&imx_uart_platform_driver);
uart_unregister_driver(&imx_uart_uart_driver);
}
module_init(imx_uart_init);
module_exit(imx_uart_exit);
MODULE_AUTHOR("Sascha Hauer");
MODULE_DESCRIPTION("IMX generic serial port driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:imx-uart");