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// SPDX-License-Identifier: GPL-2.0+
/*
* Serial Port driver for Open Firmware platform devices
*
* Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, IBM Corp.
*/
#include <linux/console.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/serial_core.h>
#include <linux/serial_reg.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/pm_runtime.h>
#include <linux/clk.h>
#include <linux/reset.h>
#include "8250.h"
struct of_serial_info {
struct clk *clk;
struct reset_control *rst;
int type;
int line;
};
#ifdef CONFIG_ARCH_TEGRA
static void tegra_serial_handle_break(struct uart_port *p)
{
unsigned int status, tmout = 10000;
do {
status = p->serial_in(p, UART_LSR);
if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS))
status = p->serial_in(p, UART_RX);
else
break;
if (--tmout == 0)
break;
udelay(1);
} while (1);
}
#else
static inline void tegra_serial_handle_break(struct uart_port *port)
{
}
#endif
/*
* Fill a struct uart_port for a given device node
*/
static int of_platform_serial_setup(struct platform_device *ofdev,
int type, struct uart_port *port,
struct of_serial_info *info)
{
struct resource resource;
struct device_node *np = ofdev->dev.of_node;
u32 clk, spd, prop;
int ret, irq;
memset(port, 0, sizeof *port);
pm_runtime_enable(&ofdev->dev);
pm_runtime_get_sync(&ofdev->dev);
if (of_property_read_u32(np, "clock-frequency", &clk)) {
/* Get clk rate through clk driver if present */
info->clk = devm_clk_get(&ofdev->dev, NULL);
if (IS_ERR(info->clk)) {
dev_warn(&ofdev->dev,
"clk or clock-frequency not defined\n");
ret = PTR_ERR(info->clk);
goto err_pmruntime;
}
ret = clk_prepare_enable(info->clk);
if (ret < 0)
goto err_pmruntime;
clk = clk_get_rate(info->clk);
}
/* If current-speed was set, then try not to change it. */
if (of_property_read_u32(np, "current-speed", &spd) == 0)
port->custom_divisor = clk / (16 * spd);
ret = of_address_to_resource(np, 0, &resource);
if (ret) {
dev_warn(&ofdev->dev, "invalid address\n");
goto err_unprepare;
}
port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT |
UPF_FIXED_TYPE;
spin_lock_init(&port->lock);
if (resource_type(&resource) == IORESOURCE_IO) {
port->iotype = UPIO_PORT;
port->iobase = resource.start;
} else {
port->mapbase = resource.start;
port->mapsize = resource_size(&resource);
/* Check for shifted address mapping */
if (of_property_read_u32(np, "reg-offset", &prop) == 0)
port->mapbase += prop;
port->iotype = UPIO_MEM;
if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
switch (prop) {
case 1:
port->iotype = UPIO_MEM;
break;
case 2:
port->iotype = UPIO_MEM16;
break;
case 4:
port->iotype = of_device_is_big_endian(np) ?
UPIO_MEM32BE : UPIO_MEM32;
break;
default:
dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
prop);
ret = -EINVAL;
goto err_unprepare;
}
}
port->flags |= UPF_IOREMAP;
}
/* Check for registers offset within the devices address range */
if (of_property_read_u32(np, "reg-shift", &prop) == 0)
port->regshift = prop;
/* Check for fifo size */
if (of_property_read_u32(np, "fifo-size", &prop) == 0)
port->fifosize = prop;
/* Check for a fixed line number */
ret = of_alias_get_id(np, "serial");
if (ret >= 0)
port->line = ret;
irq = of_irq_get(np, 0);
if (irq < 0) {
if (irq == -EPROBE_DEFER) {
ret = -EPROBE_DEFER;
goto err_unprepare;
}
/* IRQ support not mandatory */
irq = 0;
}
port->irq = irq;
info->rst = devm_reset_control_get_optional_shared(&ofdev->dev, NULL);
if (IS_ERR(info->rst)) {
ret = PTR_ERR(info->rst);
goto err_unprepare;
}
ret = reset_control_deassert(info->rst);
if (ret)
goto err_unprepare;
port->type = type;
port->uartclk = clk;
port->irqflags |= IRQF_SHARED;
if (of_property_read_bool(np, "no-loopback-test"))
port->flags |= UPF_SKIP_TEST;
port->dev = &ofdev->dev;
switch (type) {
case PORT_TEGRA:
port->handle_break = tegra_serial_handle_break;
break;
case PORT_RT2880:
port->iotype = UPIO_AU;
break;
}
if (IS_ENABLED(CONFIG_SERIAL_8250_FSL) &&
(of_device_is_compatible(np, "fsl,ns16550") ||
of_device_is_compatible(np, "fsl,16550-FIFO64")))
port->handle_irq = fsl8250_handle_irq;
return 0;
err_unprepare:
clk_disable_unprepare(info->clk);
err_pmruntime:
pm_runtime_put_sync(&ofdev->dev);
pm_runtime_disable(&ofdev->dev);
return ret;
}
/*
* Try to register a serial port
*/
static const struct of_device_id of_platform_serial_table[];
static int of_platform_serial_probe(struct platform_device *ofdev)
{
const struct of_device_id *match;
struct of_serial_info *info;
struct uart_8250_port port8250;
u32 tx_threshold;
int port_type;
int ret;
match = of_match_device(of_platform_serial_table, &ofdev->dev);
if (!match)
return -EINVAL;
if (of_property_read_bool(ofdev->dev.of_node, "used-by-rtas"))
return -EBUSY;
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (info == NULL)
return -ENOMEM;
port_type = (unsigned long)match->data;
memset(&port8250, 0, sizeof(port8250));
ret = of_platform_serial_setup(ofdev, port_type, &port8250.port, info);
if (ret)
goto err_free;
if (port8250.port.fifosize)
port8250.capabilities = UART_CAP_FIFO;
/* Check for TX FIFO threshold & set tx_loadsz */
if ((of_property_read_u32(ofdev->dev.of_node, "tx-threshold",
&tx_threshold) == 0) &&
(tx_threshold < port8250.port.fifosize))
port8250.tx_loadsz = port8250.port.fifosize - tx_threshold;
if (of_property_read_bool(ofdev->dev.of_node, "auto-flow-control"))
port8250.capabilities |= UART_CAP_AFE;
if (of_property_read_u32(ofdev->dev.of_node,
"overrun-throttle-ms",
&port8250.overrun_backoff_time_ms) != 0)
port8250.overrun_backoff_time_ms = 0;
ret = serial8250_register_8250_port(&port8250);
if (ret < 0)
goto err_dispose;
info->type = port_type;
info->line = ret;
platform_set_drvdata(ofdev, info);
return 0;
err_dispose:
irq_dispose_mapping(port8250.port.irq);
pm_runtime_put_sync(&ofdev->dev);
pm_runtime_disable(&ofdev->dev);
clk_disable_unprepare(info->clk);
err_free:
kfree(info);
return ret;
}
/*
* Release a line
*/
static int of_platform_serial_remove(struct platform_device *ofdev)
{
struct of_serial_info *info = platform_get_drvdata(ofdev);
serial8250_unregister_port(info->line);
reset_control_assert(info->rst);
pm_runtime_put_sync(&ofdev->dev);
pm_runtime_disable(&ofdev->dev);
clk_disable_unprepare(info->clk);
kfree(info);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int of_serial_suspend(struct device *dev)
{
struct of_serial_info *info = dev_get_drvdata(dev);
struct uart_8250_port *port8250 = serial8250_get_port(info->line);
struct uart_port *port = &port8250->port;
serial8250_suspend_port(info->line);
if (!uart_console(port) || console_suspend_enabled) {
pm_runtime_put_sync(dev);
clk_disable_unprepare(info->clk);
}
return 0;
}
static int of_serial_resume(struct device *dev)
{
struct of_serial_info *info = dev_get_drvdata(dev);
struct uart_8250_port *port8250 = serial8250_get_port(info->line);
struct uart_port *port = &port8250->port;
if (!uart_console(port) || console_suspend_enabled) {
pm_runtime_get_sync(dev);
clk_prepare_enable(info->clk);
}
serial8250_resume_port(info->line);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);
/*
* A few common types, add more as needed.
*/
static const struct of_device_id of_platform_serial_table[] = {
{ .compatible = "ns8250", .data = (void *)PORT_8250, },
{ .compatible = "ns16450", .data = (void *)PORT_16450, },
{ .compatible = "ns16550a", .data = (void *)PORT_16550A, },
{ .compatible = "ns16550", .data = (void *)PORT_16550, },
{ .compatible = "ns16750", .data = (void *)PORT_16750, },
{ .compatible = "ns16850", .data = (void *)PORT_16850, },
{ .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
{ .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
{ .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, },
{ .compatible = "altr,16550-FIFO32",
.data = (void *)PORT_ALTR_16550_F32, },
{ .compatible = "altr,16550-FIFO64",
.data = (void *)PORT_ALTR_16550_F64, },
{ .compatible = "altr,16550-FIFO128",
.data = (void *)PORT_ALTR_16550_F128, },
{ .compatible = "mediatek,mtk-btif",
.data = (void *)PORT_MTK_BTIF, },
{ .compatible = "mrvl,mmp-uart",
.data = (void *)PORT_XSCALE, },
{ .compatible = "ti,da830-uart", .data = (void *)PORT_DA830, },
{ .compatible = "nuvoton,npcm750-uart", .data = (void *)PORT_NPCM, },
{ /* end of list */ },
};
MODULE_DEVICE_TABLE(of, of_platform_serial_table);
static struct platform_driver of_platform_serial_driver = {
.driver = {
.name = "of_serial",
.of_match_table = of_platform_serial_table,
.pm = &of_serial_pm_ops,
},
.probe = of_platform_serial_probe,
.remove = of_platform_serial_remove,
};
module_platform_driver(of_platform_serial_driver);
MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");