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OpenCloudOS-Kernel/drivers/tty/serial/8250/8250_dw.c

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/*
* Synopsys DesignWare 8250 driver.
*
* Copyright 2011 Picochip, Jamie Iles.
* Copyright 2013 Intel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* The Synopsys DesignWare 8250 has an extra feature whereby it detects if the
* LCR is written whilst busy. If it is, then a busy detect interrupt is
* raised, the LCR needs to be rewritten and the uart status register read.
*/
#include <linux/device.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/serial_8250.h>
#include <linux/serial_core.h>
#include <linux/serial_reg.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/acpi.h>
/* Offsets for the DesignWare specific registers */
#define DW_UART_USR 0x1f /* UART Status Register */
#define DW_UART_CPR 0xf4 /* Component Parameter Register */
#define DW_UART_UCV 0xf8 /* UART Component Version */
/* Intel Low Power Subsystem specific */
#define LPSS_PRV_CLOCK_PARAMS 0x800
/* Component Parameter Register bits */
#define DW_UART_CPR_ABP_DATA_WIDTH (3 << 0)
#define DW_UART_CPR_AFCE_MODE (1 << 4)
#define DW_UART_CPR_THRE_MODE (1 << 5)
#define DW_UART_CPR_SIR_MODE (1 << 6)
#define DW_UART_CPR_SIR_LP_MODE (1 << 7)
#define DW_UART_CPR_ADDITIONAL_FEATURES (1 << 8)
#define DW_UART_CPR_FIFO_ACCESS (1 << 9)
#define DW_UART_CPR_FIFO_STAT (1 << 10)
#define DW_UART_CPR_SHADOW (1 << 11)
#define DW_UART_CPR_ENCODED_PARMS (1 << 12)
#define DW_UART_CPR_DMA_EXTRA (1 << 13)
#define DW_UART_CPR_FIFO_MODE (0xff << 16)
/* Helper for fifo size calculation */
#define DW_UART_CPR_FIFO_SIZE(a) (((a >> 16) & 0xff) * 16)
struct dw8250_data {
int last_lcr;
int line;
};
static void dw8250_serial_out(struct uart_port *p, int offset, int value)
{
struct dw8250_data *d = p->private_data;
if (offset == UART_LCR)
d->last_lcr = value;
offset <<= p->regshift;
writeb(value, p->membase + offset);
}
static unsigned int dw8250_serial_in(struct uart_port *p, int offset)
{
offset <<= p->regshift;
return readb(p->membase + offset);
}
static void dw8250_serial_out32(struct uart_port *p, int offset, int value)
{
struct dw8250_data *d = p->private_data;
if (offset == UART_LCR)
d->last_lcr = value;
offset <<= p->regshift;
writel(value, p->membase + offset);
}
static unsigned int dw8250_serial_in32(struct uart_port *p, int offset)
{
offset <<= p->regshift;
return readl(p->membase + offset);
}
static int dw8250_handle_irq(struct uart_port *p)
{
struct dw8250_data *d = p->private_data;
unsigned int iir = p->serial_in(p, UART_IIR);
if (serial8250_handle_irq(p, iir)) {
return 1;
} else if ((iir & UART_IIR_BUSY) == UART_IIR_BUSY) {
/* Clear the USR and write the LCR again. */
(void)p->serial_in(p, DW_UART_USR);
p->serial_out(p, d->last_lcr, UART_LCR);
return 1;
}
return 0;
}
static int dw8250_probe_of(struct uart_port *p)
{
struct device_node *np = p->dev->of_node;
u32 val;
if (!of_property_read_u32(np, "reg-io-width", &val)) {
switch (val) {
case 1:
break;
case 4:
p->iotype = UPIO_MEM32;
p->serial_in = dw8250_serial_in32;
p->serial_out = dw8250_serial_out32;
break;
default:
dev_err(p->dev, "unsupported reg-io-width (%u)\n", val);
return -EINVAL;
}
}
if (!of_property_read_u32(np, "reg-shift", &val))
p->regshift = val;
if (of_property_read_u32(np, "clock-frequency", &val)) {
dev_err(p->dev, "no clock-frequency property set\n");
return -EINVAL;
}
p->uartclk = val;
return 0;
}
static int dw8250_probe_acpi(struct uart_port *p)
{
const struct acpi_device_id *id;
u32 reg;
id = acpi_match_device(p->dev->driver->acpi_match_table, p->dev);
if (!id)
return -ENODEV;
p->iotype = UPIO_MEM32;
p->serial_in = dw8250_serial_in32;
p->serial_out = dw8250_serial_out32;
p->regshift = 2;
p->uartclk = (unsigned int)id->driver_data;
/* Fix Haswell issue where the clocks do not get enabled */
if (!strcmp(id->id, "INT33C4") || !strcmp(id->id, "INT33C5")) {
reg = readl(p->membase + LPSS_PRV_CLOCK_PARAMS);
writel(reg | 1, p->membase + LPSS_PRV_CLOCK_PARAMS);
}
return 0;
}
static void dw8250_setup_port(struct uart_8250_port *up)
{
struct uart_port *p = &up->port;
u32 reg = readl(p->membase + DW_UART_UCV);
/*
* If the Component Version Register returns zero, we know that
* ADDITIONAL_FEATURES are not enabled. No need to go any further.
*/
if (!reg)
return;
dev_dbg_ratelimited(p->dev, "Designware UART version %c.%c%c\n",
(reg >> 24) & 0xff, (reg >> 16) & 0xff, (reg >> 8) & 0xff);
reg = readl(p->membase + DW_UART_CPR);
if (!reg)
return;
/* Select the type based on fifo */
if (reg & DW_UART_CPR_FIFO_MODE) {
p->type = PORT_16550A;
p->flags |= UPF_FIXED_TYPE;
p->fifosize = DW_UART_CPR_FIFO_SIZE(reg);
up->tx_loadsz = p->fifosize;
}
}
static int dw8250_probe(struct platform_device *pdev)
{
struct uart_8250_port uart = {};
struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
struct dw8250_data *data;
int err;
if (!regs || !irq) {
dev_err(&pdev->dev, "no registers/irq defined\n");
return -EINVAL;
}
spin_lock_init(&uart.port.lock);
uart.port.mapbase = regs->start;
uart.port.irq = irq->start;
uart.port.handle_irq = dw8250_handle_irq;
uart.port.type = PORT_8250;
uart.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT;
uart.port.dev = &pdev->dev;
uart.port.membase = ioremap(regs->start, resource_size(regs));
if (!uart.port.membase)
return -ENOMEM;
uart.port.iotype = UPIO_MEM;
uart.port.serial_in = dw8250_serial_in;
uart.port.serial_out = dw8250_serial_out;
if (pdev->dev.of_node) {
err = dw8250_probe_of(&uart.port);
if (err)
return err;
} else if (ACPI_HANDLE(&pdev->dev)) {
err = dw8250_probe_acpi(&uart.port);
if (err)
return err;
} else {
return -ENODEV;
}
dw8250_setup_port(&uart);
data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
uart.port.private_data = data;
data->line = serial8250_register_8250_port(&uart);
if (data->line < 0)
return data->line;
platform_set_drvdata(pdev, data);
return 0;
}
static int dw8250_remove(struct platform_device *pdev)
{
struct dw8250_data *data = platform_get_drvdata(pdev);
serial8250_unregister_port(data->line);
return 0;
}
#ifdef CONFIG_PM
static int dw8250_suspend(struct platform_device *pdev, pm_message_t state)
{
struct dw8250_data *data = platform_get_drvdata(pdev);
serial8250_suspend_port(data->line);
return 0;
}
static int dw8250_resume(struct platform_device *pdev)
{
struct dw8250_data *data = platform_get_drvdata(pdev);
serial8250_resume_port(data->line);
return 0;
}
#else
#define dw8250_suspend NULL
#define dw8250_resume NULL
#endif /* CONFIG_PM */
static const struct of_device_id dw8250_of_match[] = {
{ .compatible = "snps,dw-apb-uart" },
{ /* Sentinel */ }
};
MODULE_DEVICE_TABLE(of, dw8250_of_match);
static const struct acpi_device_id dw8250_acpi_match[] = {
{ "INT33C4", 100000000 },
{ "INT33C5", 100000000 },
{ },
};
MODULE_DEVICE_TABLE(acpi, dw8250_acpi_match);
static struct platform_driver dw8250_platform_driver = {
.driver = {
.name = "dw-apb-uart",
.owner = THIS_MODULE,
.of_match_table = dw8250_of_match,
.acpi_match_table = ACPI_PTR(dw8250_acpi_match),
},
.probe = dw8250_probe,
.remove = dw8250_remove,
.suspend = dw8250_suspend,
.resume = dw8250_resume,
};
module_platform_driver(dw8250_platform_driver);
MODULE_AUTHOR("Jamie Iles");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Synopsys DesignWare 8250 serial port driver");
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