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// SPDX-License-Identifier: GPL-2.0
/*
* Renesas Emma Mobile 8250 driver
*
* Copyright (C) 2012 Magnus Damm
*/
#include <linux/device.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/serial_8250.h>
#include <linux/serial_reg.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include "8250.h"
#define UART_DLL_EM 9
#define UART_DLM_EM 10
#define UART_HCR0_EM 11
/*
* A high value for UART_FCR_EM avoids overlapping with existing UART_*
* register defines. UART_FCR_EM_HW is the real HW register offset.
*/
#define UART_FCR_EM 0x10003
#define UART_FCR_EM_HW 3
#define UART_HCR0_EM_SW_RESET BIT(7) /* SW Reset */
struct serial8250_em_priv {
int line;
};
static void serial8250_em_serial_out_helper(struct uart_port *p, int offset,
int value)
{
switch (offset) {
case UART_TX: /* TX @ 0x00 */
writeb(value, p->membase);
break;
case UART_LCR: /* LCR @ 0x10 (+1) */
case UART_MCR: /* MCR @ 0x14 (+1) */
case UART_SCR: /* SCR @ 0x20 (+1) */
writel(value, p->membase + ((offset + 1) << 2));
break;
case UART_FCR_EM:
writel(value, p->membase + (UART_FCR_EM_HW << 2));
break;
case UART_IER: /* IER @ 0x04 */
value &= 0x0f; /* only 4 valid bits - not Xscale */
fallthrough;
case UART_DLL_EM: /* DLL @ 0x24 (+9) */
case UART_DLM_EM: /* DLM @ 0x28 (+9) */
case UART_HCR0_EM: /* HCR0 @ 0x2c */
writel(value, p->membase + (offset << 2));
break;
}
}
static unsigned int serial8250_em_serial_in(struct uart_port *p, int offset)
{
switch (offset) {
case UART_RX: /* RX @ 0x00 */
return readb(p->membase);
case UART_LCR: /* LCR @ 0x10 (+1) */
case UART_MCR: /* MCR @ 0x14 (+1) */
case UART_LSR: /* LSR @ 0x18 (+1) */
case UART_MSR: /* MSR @ 0x1c (+1) */
case UART_SCR: /* SCR @ 0x20 (+1) */
return readl(p->membase + ((offset + 1) << 2));
case UART_FCR_EM:
return readl(p->membase + (UART_FCR_EM_HW << 2));
case UART_IER: /* IER @ 0x04 */
case UART_IIR: /* IIR @ 0x08 */
case UART_DLL_EM: /* DLL @ 0x24 (+9) */
case UART_DLM_EM: /* DLM @ 0x28 (+9) */
case UART_HCR0_EM: /* HCR0 @ 0x2c */
return readl(p->membase + (offset << 2));
}
return 0;
}
static void serial8250_em_reg_update(struct uart_port *p, int off, int value)
{
unsigned int ier, fcr, lcr, mcr, hcr0;
ier = serial8250_em_serial_in(p, UART_IER);
fcr = serial8250_em_serial_in(p, UART_FCR_EM);
lcr = serial8250_em_serial_in(p, UART_LCR);
mcr = serial8250_em_serial_in(p, UART_MCR);
hcr0 = serial8250_em_serial_in(p, UART_HCR0_EM);
serial8250_em_serial_out_helper(p, UART_FCR_EM, fcr |
UART_FCR_CLEAR_RCVR |
UART_FCR_CLEAR_XMIT);
serial8250_em_serial_out_helper(p, UART_HCR0_EM, hcr0 |
UART_HCR0_EM_SW_RESET);
serial8250_em_serial_out_helper(p, UART_HCR0_EM, hcr0 &
~UART_HCR0_EM_SW_RESET);
switch (off) {
case UART_FCR_EM:
fcr = value;
break;
case UART_LCR:
lcr = value;
break;
case UART_MCR:
mcr = value;
break;
}
serial8250_em_serial_out_helper(p, UART_IER, ier);
serial8250_em_serial_out_helper(p, UART_FCR_EM, fcr);
serial8250_em_serial_out_helper(p, UART_MCR, mcr);
serial8250_em_serial_out_helper(p, UART_LCR, lcr);
serial8250_em_serial_out_helper(p, UART_HCR0_EM, hcr0);
}
static void serial8250_em_serial_out(struct uart_port *p, int offset, int value)
{
switch (offset) {
case UART_TX:
case UART_SCR:
case UART_IER:
case UART_DLL_EM:
case UART_DLM_EM:
serial8250_em_serial_out_helper(p, offset, value);
break;
case UART_FCR:
serial8250_em_reg_update(p, UART_FCR_EM, value);
break;
case UART_LCR:
case UART_MCR:
serial8250_em_reg_update(p, offset, value);
break;
}
}
static u32 serial8250_em_serial_dl_read(struct uart_8250_port *up)
{
return serial_in(up, UART_DLL_EM) | serial_in(up, UART_DLM_EM) << 8;
}
static void serial8250_em_serial_dl_write(struct uart_8250_port *up, u32 value)
{
serial_out(up, UART_DLL_EM, value & 0xff);
serial_out(up, UART_DLM_EM, value >> 8 & 0xff);
}
static int serial8250_em_probe(struct platform_device *pdev)
{
struct serial8250_em_priv *priv;
struct device *dev = &pdev->dev;
struct uart_8250_port up;
struct resource *regs;
struct clk *sclk;
int irq, ret;
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!regs)
return dev_err_probe(dev, -EINVAL, "missing registers\n");
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
sclk = devm_clk_get_enabled(dev, "sclk");
if (IS_ERR(sclk))
return dev_err_probe(dev, PTR_ERR(sclk), "unable to get clock\n");
memset(&up, 0, sizeof(up));
up.port.mapbase = regs->start;
up.port.irq = irq;
up.port.type = PORT_16750;
up.port.flags = UPF_FIXED_PORT | UPF_IOREMAP | UPF_FIXED_TYPE;
up.port.dev = dev;
up.port.private_data = priv;
up.port.uartclk = clk_get_rate(sclk);
up.port.iotype = UPIO_MEM32;
up.port.serial_in = serial8250_em_serial_in;
up.port.serial_out = serial8250_em_serial_out;
up.dl_read = serial8250_em_serial_dl_read;
up.dl_write = serial8250_em_serial_dl_write;
ret = serial8250_register_8250_port(&up);
if (ret < 0)
return dev_err_probe(dev, ret, "unable to register 8250 port\n");
priv->line = ret;
platform_set_drvdata(pdev, priv);
return 0;
}
static void serial8250_em_remove(struct platform_device *pdev)
{
struct serial8250_em_priv *priv = platform_get_drvdata(pdev);
serial8250_unregister_port(priv->line);
}
static const struct of_device_id serial8250_em_dt_ids[] = {
{ .compatible = "renesas,em-uart", },
{},
};
MODULE_DEVICE_TABLE(of, serial8250_em_dt_ids);
static struct platform_driver serial8250_em_platform_driver = {
.driver = {
.name = "serial8250-em",
.of_match_table = serial8250_em_dt_ids,
},
.probe = serial8250_em_probe,
.remove = serial8250_em_remove,
};
module_platform_driver(serial8250_em_platform_driver);
MODULE_AUTHOR("Magnus Damm");
MODULE_DESCRIPTION("Renesas Emma Mobile 8250 Driver");
MODULE_LICENSE("GPL v2");
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