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// SPDX-License-Identifier: GPL-2.0-only
/* drivers/net/ethernet/micrel/ks8851.c
*
* Copyright 2009 Simtec Electronics
* http://www.simtec.co.uk/
* Ben Dooks <ben@simtec.co.uk>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/cache.h>
#include <linux/crc32.h>
#include <linux/mii.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <linux/of_net.h>
#include "ks8851.h"
static int msg_enable;
/**
* struct ks8851_net_spi - KS8851 SPI driver private data
* @lock: Lock to ensure that the device is not accessed when busy.
* @tx_work: Work queue for tx packets
* @ks8851: KS8851 driver common private data
* @spidev: The spi device we're bound to.
* @spi_msg1: pre-setup SPI transfer with one message, @spi_xfer1.
* @spi_msg2: pre-setup SPI transfer with two messages, @spi_xfer2.
* @spi_xfer1: @spi_msg1 SPI transfer structure
* @spi_xfer2: @spi_msg2 SPI transfer structure
*
* The @lock ensures that the chip is protected when certain operations are
* in progress. When the read or write packet transfer is in progress, most
* of the chip registers are not ccessible until the transfer is finished and
* the DMA has been de-asserted.
*/
struct ks8851_net_spi {
struct ks8851_net ks8851;
struct mutex lock;
struct work_struct tx_work;
struct spi_device *spidev;
struct spi_message spi_msg1;
struct spi_message spi_msg2;
struct spi_transfer spi_xfer1;
struct spi_transfer spi_xfer2[2];
};
#define to_ks8851_spi(ks) container_of((ks), struct ks8851_net_spi, ks8851)
/* SPI frame opcodes */
#define KS_SPIOP_RD 0x00
#define KS_SPIOP_WR 0x40
#define KS_SPIOP_RXFIFO 0x80
#define KS_SPIOP_TXFIFO 0xC0
/* shift for byte-enable data */
#define BYTE_EN(_x) ((_x) << 2)
/* turn register number and byte-enable mask into data for start of packet */
#define MK_OP(_byteen, _reg) \
(BYTE_EN(_byteen) | (_reg) << (8 + 2) | (_reg) >> 6)
/**
* ks8851_lock_spi - register access lock
* @ks: The chip state
* @flags: Spinlock flags
*
* Claim chip register access lock
*/
static void ks8851_lock_spi(struct ks8851_net *ks, unsigned long *flags)
{
struct ks8851_net_spi *kss = to_ks8851_spi(ks);
mutex_lock(&kss->lock);
}
/**
* ks8851_unlock_spi - register access unlock
* @ks: The chip state
* @flags: Spinlock flags
*
* Release chip register access lock
*/
static void ks8851_unlock_spi(struct ks8851_net *ks, unsigned long *flags)
{
struct ks8851_net_spi *kss = to_ks8851_spi(ks);
mutex_unlock(&kss->lock);
}
/* SPI register read/write calls.
*
* All these calls issue SPI transactions to access the chip's registers. They
* all require that the necessary lock is held to prevent accesses when the
* chip is busy transferring packet data (RX/TX FIFO accesses).
*/
/**
* ks8851_wrreg16_spi - write 16bit register value to chip via SPI
* @ks: The chip state
* @reg: The register address
* @val: The value to write
*
* Issue a write to put the value @val into the register specified in @reg.
*/
static void ks8851_wrreg16_spi(struct ks8851_net *ks, unsigned int reg,
unsigned int val)
{
struct ks8851_net_spi *kss = to_ks8851_spi(ks);
struct spi_transfer *xfer = &kss->spi_xfer1;
struct spi_message *msg = &kss->spi_msg1;
__le16 txb[2];
int ret;
txb[0] = cpu_to_le16(MK_OP(reg & 2 ? 0xC : 0x03, reg) | KS_SPIOP_WR);
txb[1] = cpu_to_le16(val);
xfer->tx_buf = txb;
xfer->rx_buf = NULL;
xfer->len = 4;
ret = spi_sync(kss->spidev, msg);
if (ret < 0)
netdev_err(ks->netdev, "spi_sync() failed\n");
}
/**
* ks8851_rdreg - issue read register command and return the data
* @ks: The device state
* @op: The register address and byte enables in message format.
* @rxb: The RX buffer to return the result into
* @rxl: The length of data expected.
*
* This is the low level read call that issues the necessary spi message(s)
* to read data from the register specified in @op.
*/
static void ks8851_rdreg(struct ks8851_net *ks, unsigned int op,
u8 *rxb, unsigned int rxl)
{
struct ks8851_net_spi *kss = to_ks8851_spi(ks);
struct spi_transfer *xfer;
struct spi_message *msg;
__le16 *txb = (__le16 *)ks->txd;
u8 *trx = ks->rxd;
int ret;
txb[0] = cpu_to_le16(op | KS_SPIOP_RD);
if (kss->spidev->controller->flags & SPI_CONTROLLER_HALF_DUPLEX) {
msg = &kss->spi_msg2;
xfer = kss->spi_xfer2;
xfer->tx_buf = txb;
xfer->rx_buf = NULL;
xfer->len = 2;
xfer++;
xfer->tx_buf = NULL;
xfer->rx_buf = trx;
xfer->len = rxl;
} else {
msg = &kss->spi_msg1;
xfer = &kss->spi_xfer1;
xfer->tx_buf = txb;
xfer->rx_buf = trx;
xfer->len = rxl + 2;
}
ret = spi_sync(kss->spidev, msg);
if (ret < 0)
netdev_err(ks->netdev, "read: spi_sync() failed\n");
else if (kss->spidev->controller->flags & SPI_CONTROLLER_HALF_DUPLEX)
memcpy(rxb, trx, rxl);
else
memcpy(rxb, trx + 2, rxl);
}
/**
* ks8851_rdreg16_spi - read 16 bit register from device via SPI
* @ks: The chip information
* @reg: The register address
*
* Read a 16bit register from the chip, returning the result
*/
static unsigned int ks8851_rdreg16_spi(struct ks8851_net *ks, unsigned int reg)
{
__le16 rx = 0;
ks8851_rdreg(ks, MK_OP(reg & 2 ? 0xC : 0x3, reg), (u8 *)&rx, 2);
return le16_to_cpu(rx);
}
/**
* ks8851_rdfifo_spi - read data from the receive fifo via SPI
* @ks: The device state.
* @buff: The buffer address
* @len: The length of the data to read
*
* Issue an RXQ FIFO read command and read the @len amount of data from
* the FIFO into the buffer specified by @buff.
*/
static void ks8851_rdfifo_spi(struct ks8851_net *ks, u8 *buff, unsigned int len)
{
struct ks8851_net_spi *kss = to_ks8851_spi(ks);
struct spi_transfer *xfer = kss->spi_xfer2;
struct spi_message *msg = &kss->spi_msg2;
u8 txb[1];
int ret;
netif_dbg(ks, rx_status, ks->netdev,
"%s: %d@%p\n", __func__, len, buff);
/* set the operation we're issuing */
txb[0] = KS_SPIOP_RXFIFO;
xfer->tx_buf = txb;
xfer->rx_buf = NULL;
xfer->len = 1;
xfer++;
xfer->rx_buf = buff;
xfer->tx_buf = NULL;
xfer->len = len;
ret = spi_sync(kss->spidev, msg);
if (ret < 0)
netdev_err(ks->netdev, "%s: spi_sync() failed\n", __func__);
}
/**
* ks8851_wrfifo_spi - write packet to TX FIFO via SPI
* @ks: The device state.
* @txp: The sk_buff to transmit.
* @irq: IRQ on completion of the packet.
*
* Send the @txp to the chip. This means creating the relevant packet header
* specifying the length of the packet and the other information the chip
* needs, such as IRQ on completion. Send the header and the packet data to
* the device.
*/
static void ks8851_wrfifo_spi(struct ks8851_net *ks, struct sk_buff *txp,
bool irq)
{
struct ks8851_net_spi *kss = to_ks8851_spi(ks);
struct spi_transfer *xfer = kss->spi_xfer2;
struct spi_message *msg = &kss->spi_msg2;
unsigned int fid = 0;
int ret;
netif_dbg(ks, tx_queued, ks->netdev, "%s: skb %p, %d@%p, irq %d\n",
__func__, txp, txp->len, txp->data, irq);
fid = ks->fid++;
fid &= TXFR_TXFID_MASK;
if (irq)
fid |= TXFR_TXIC; /* irq on completion */
/* start header at txb[1] to align txw entries */
ks->txh.txb[1] = KS_SPIOP_TXFIFO;
ks->txh.txw[1] = cpu_to_le16(fid);
ks->txh.txw[2] = cpu_to_le16(txp->len);
xfer->tx_buf = &ks->txh.txb[1];
xfer->rx_buf = NULL;
xfer->len = 5;
xfer++;
xfer->tx_buf = txp->data;
xfer->rx_buf = NULL;
xfer->len = ALIGN(txp->len, 4);
ret = spi_sync(kss->spidev, msg);
if (ret < 0)
netdev_err(ks->netdev, "%s: spi_sync() failed\n", __func__);
}
/**
* calc_txlen - calculate size of message to send packet
* @len: Length of data
*
* Returns the size of the TXFIFO message needed to send
* this packet.
*/
static unsigned int calc_txlen(unsigned int len)
{
return ALIGN(len + 4, 4);
}
/**
* ks8851_rx_skb_spi - receive skbuff
* @ks: The device state
* @skb: The skbuff
*/
static void ks8851_rx_skb_spi(struct ks8851_net *ks, struct sk_buff *skb)
{
netif_rx(skb);
}
/**
* ks8851_tx_work - process tx packet(s)
* @work: The work strucutre what was scheduled.
*
* This is called when a number of packets have been scheduled for
* transmission and need to be sent to the device.
*/
static void ks8851_tx_work(struct work_struct *work)
{
unsigned int dequeued_len = 0;
struct ks8851_net_spi *kss;
unsigned short tx_space;
struct ks8851_net *ks;
unsigned long flags;
struct sk_buff *txb;
bool last;
kss = container_of(work, struct ks8851_net_spi, tx_work);
ks = &kss->ks8851;
last = skb_queue_empty(&ks->txq);
ks8851_lock_spi(ks, &flags);
while (!last) {
txb = skb_dequeue(&ks->txq);
last = skb_queue_empty(&ks->txq);
if (txb) {
dequeued_len += calc_txlen(txb->len);
ks8851_wrreg16_spi(ks, KS_RXQCR,
ks->rc_rxqcr | RXQCR_SDA);
ks8851_wrfifo_spi(ks, txb, last);
ks8851_wrreg16_spi(ks, KS_RXQCR, ks->rc_rxqcr);
ks8851_wrreg16_spi(ks, KS_TXQCR, TXQCR_METFE);
ks8851_done_tx(ks, txb);
}
}
tx_space = ks8851_rdreg16_spi(ks, KS_TXMIR);
spin_lock(&ks->statelock);
ks->queued_len -= dequeued_len;
ks->tx_space = tx_space;
spin_unlock(&ks->statelock);
ks8851_unlock_spi(ks, &flags);
}
/**
* ks8851_flush_tx_work_spi - flush outstanding TX work
* @ks: The device state
*/
static void ks8851_flush_tx_work_spi(struct ks8851_net *ks)
{
struct ks8851_net_spi *kss = to_ks8851_spi(ks);
flush_work(&kss->tx_work);
}
/**
* ks8851_start_xmit_spi - transmit packet using SPI
* @skb: The buffer to transmit
* @dev: The device used to transmit the packet.
*
* Called by the network layer to transmit the @skb. Queue the packet for
* the device and schedule the necessary work to transmit the packet when
* it is free.
*
* We do this to firstly avoid sleeping with the network device locked,
* and secondly so we can round up more than one packet to transmit which
* means we can try and avoid generating too many transmit done interrupts.
*/
static netdev_tx_t ks8851_start_xmit_spi(struct sk_buff *skb,
struct net_device *dev)
{
unsigned int needed = calc_txlen(skb->len);
struct ks8851_net *ks = netdev_priv(dev);
netdev_tx_t ret = NETDEV_TX_OK;
struct ks8851_net_spi *kss;
kss = to_ks8851_spi(ks);
netif_dbg(ks, tx_queued, ks->netdev,
"%s: skb %p, %d@%p\n", __func__, skb, skb->len, skb->data);
spin_lock(&ks->statelock);
if (ks->queued_len + needed > ks->tx_space) {
netif_stop_queue(dev);
ret = NETDEV_TX_BUSY;
} else {
ks->queued_len += needed;
skb_queue_tail(&ks->txq, skb);
}
spin_unlock(&ks->statelock);
if (ret == NETDEV_TX_OK)
schedule_work(&kss->tx_work);
return ret;
}
static int ks8851_probe_spi(struct spi_device *spi)
{
struct device *dev = &spi->dev;
struct ks8851_net_spi *kss;
struct net_device *netdev;
struct ks8851_net *ks;
netdev = devm_alloc_etherdev(dev, sizeof(struct ks8851_net_spi));
if (!netdev)
return -ENOMEM;
spi->bits_per_word = 8;
kss = netdev_priv(netdev);
ks = &kss->ks8851;
ks->lock = ks8851_lock_spi;
ks->unlock = ks8851_unlock_spi;
ks->rdreg16 = ks8851_rdreg16_spi;
ks->wrreg16 = ks8851_wrreg16_spi;
ks->rdfifo = ks8851_rdfifo_spi;
ks->wrfifo = ks8851_wrfifo_spi;
ks->start_xmit = ks8851_start_xmit_spi;
ks->rx_skb = ks8851_rx_skb_spi;
ks->flush_tx_work = ks8851_flush_tx_work_spi;
#define STD_IRQ (IRQ_LCI | /* Link Change */ \
IRQ_TXI | /* TX done */ \
IRQ_RXI | /* RX done */ \
IRQ_SPIBEI | /* SPI bus error */ \
IRQ_TXPSI | /* TX process stop */ \
IRQ_RXPSI) /* RX process stop */
ks->rc_ier = STD_IRQ;
kss->spidev = spi;
mutex_init(&kss->lock);
INIT_WORK(&kss->tx_work, ks8851_tx_work);
/* initialise pre-made spi transfer messages */
spi_message_init(&kss->spi_msg1);
spi_message_add_tail(&kss->spi_xfer1, &kss->spi_msg1);
spi_message_init(&kss->spi_msg2);
spi_message_add_tail(&kss->spi_xfer2[0], &kss->spi_msg2);
spi_message_add_tail(&kss->spi_xfer2[1], &kss->spi_msg2);
netdev->irq = spi->irq;
return ks8851_probe_common(netdev, dev, msg_enable);
}
static void ks8851_remove_spi(struct spi_device *spi)
{
ks8851_remove_common(&spi->dev);
}
static const struct of_device_id ks8851_match_table[] = {
{ .compatible = "micrel,ks8851" },
{ }
};
MODULE_DEVICE_TABLE(of, ks8851_match_table);
static struct spi_driver ks8851_driver = {
.driver = {
.name = "ks8851",
.of_match_table = ks8851_match_table,
.pm = &ks8851_pm_ops,
},
.probe = ks8851_probe_spi,
.remove = ks8851_remove_spi,
};
module_spi_driver(ks8851_driver);
MODULE_DESCRIPTION("KS8851 Network driver");
MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
MODULE_LICENSE("GPL");
module_param_named(message, msg_enable, int, 0);
MODULE_PARM_DESC(message, "Message verbosity level (0=none, 31=all)");
MODULE_ALIAS("spi:ks8851");