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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2018 Anup Patel <anup@brainfault.org>
*/
#include <clk.h>
#include <common.h>
#include <debug_uart.h>
#include <dm.h>
#include <errno.h>
#include <fdtdec.h>
#include <watchdog.h>
#include <asm/io.h>
#include <linux/compiler.h>
#include <serial.h>
DECLARE_GLOBAL_DATA_PTR;
#define UART_TXFIFO_FULL 0x80000000
#define UART_RXFIFO_EMPTY 0x80000000
#define UART_RXFIFO_DATA 0x000000ff
#define UART_TXCTRL_TXEN 0x1
#define UART_RXCTRL_RXEN 0x1
struct uart_sifive {
u32 txfifo;
u32 rxfifo;
u32 txctrl;
u32 rxctrl;
u32 ie;
u32 ip;
u32 div;
};
struct sifive_uart_platdata {
unsigned int clock;
int saved_input_char;
struct uart_sifive *regs;
};
/* Set up the baud rate in gd struct */
static void _sifive_serial_setbrg(struct uart_sifive *regs,
unsigned long clock, unsigned long baud)
{
writel((u32)((clock / baud) - 1), ®s->div);
}
static void _sifive_serial_init(struct uart_sifive *regs)
{
writel(UART_TXCTRL_TXEN, ®s->txctrl);
writel(UART_RXCTRL_RXEN, ®s->rxctrl);
writel(0, ®s->ie);
}
static int _sifive_serial_putc(struct uart_sifive *regs, const char c)
{
if (readl(®s->txfifo) & UART_TXFIFO_FULL)
return -EAGAIN;
writel(c, ®s->txfifo);
return 0;
}
static int _sifive_serial_getc(struct uart_sifive *regs)
{
int ch = readl(®s->rxfifo);
if (ch & UART_RXFIFO_EMPTY)
return -EAGAIN;
ch &= UART_RXFIFO_DATA;
return (!ch) ? -EAGAIN : ch;
}
static int sifive_serial_setbrg(struct udevice *dev, int baudrate)
{
int err;
struct clk clk;
struct sifive_uart_platdata *platdata = dev_get_platdata(dev);
err = clk_get_by_index(dev, 0, &clk);
if (!err) {
err = clk_get_rate(&clk);
if (!IS_ERR_VALUE(err))
platdata->clock = err;
} else if (err != -ENOENT && err != -ENODEV && err != -ENOSYS) {
debug("SiFive UART failed to get clock\n");
return err;
}
if (!platdata->clock)
platdata->clock = dev_read_u32_default(dev, "clock-frequency", 0);
if (!platdata->clock) {
debug("SiFive UART clock not defined\n");
return -EINVAL;
}
_sifive_serial_setbrg(platdata->regs, platdata->clock, baudrate);
return 0;
}
static int sifive_serial_probe(struct udevice *dev)
{
struct sifive_uart_platdata *platdata = dev_get_platdata(dev);
/* No need to reinitialize the UART after relocation */
if (gd->flags & GD_FLG_RELOC)
return 0;
platdata->saved_input_char = 0;
_sifive_serial_init(platdata->regs);
return 0;
}
static int sifive_serial_getc(struct udevice *dev)
{
int c;
struct sifive_uart_platdata *platdata = dev_get_platdata(dev);
struct uart_sifive *regs = platdata->regs;
if (platdata->saved_input_char > 0) {
c = platdata->saved_input_char;
platdata->saved_input_char = 0;
return c;
}
while ((c = _sifive_serial_getc(regs)) == -EAGAIN) ;
return c;
}
static int sifive_serial_putc(struct udevice *dev, const char ch)
{
int rc;
struct sifive_uart_platdata *platdata = dev_get_platdata(dev);
while ((rc = _sifive_serial_putc(platdata->regs, ch)) == -EAGAIN) ;
return rc;
}
static int sifive_serial_pending(struct udevice *dev, bool input)
{
struct sifive_uart_platdata *platdata = dev_get_platdata(dev);
struct uart_sifive *regs = platdata->regs;
if (input) {
if (platdata->saved_input_char > 0)
return 1;
platdata->saved_input_char = _sifive_serial_getc(regs);
return (platdata->saved_input_char > 0) ? 1 : 0;
} else {
return !!(readl(®s->txfifo) & UART_TXFIFO_FULL);
}
}
static int sifive_serial_ofdata_to_platdata(struct udevice *dev)
{
struct sifive_uart_platdata *platdata = dev_get_platdata(dev);
platdata->regs = (struct uart_sifive *)dev_read_addr(dev);
if (IS_ERR(platdata->regs))
return PTR_ERR(platdata->regs);
return 0;
}
static const struct dm_serial_ops sifive_serial_ops = {
.putc = sifive_serial_putc,
.getc = sifive_serial_getc,
.pending = sifive_serial_pending,
.setbrg = sifive_serial_setbrg,
};
static const struct udevice_id sifive_serial_ids[] = {
{ .compatible = "sifive,uart0" },
{ }
};
U_BOOT_DRIVER(serial_sifive) = {
.name = "serial_sifive",
.id = UCLASS_SERIAL,
.of_match = sifive_serial_ids,
.ofdata_to_platdata = sifive_serial_ofdata_to_platdata,
.platdata_auto_alloc_size = sizeof(struct sifive_uart_platdata),
.probe = sifive_serial_probe,
.ops = &sifive_serial_ops,
};
#ifdef CONFIG_DEBUG_UART_SIFIVE
static inline void _debug_uart_init(void)
{
struct uart_sifive *regs =
(struct uart_sifive *)CONFIG_DEBUG_UART_BASE;
_sifive_serial_setbrg(regs, CONFIG_DEBUG_UART_CLOCK,
CONFIG_BAUDRATE);
_sifive_serial_init(regs);
}
static inline void _debug_uart_putc(int ch)
{
struct uart_sifive *regs =
(struct uart_sifive *)CONFIG_DEBUG_UART_BASE;
while (_sifive_serial_putc(regs, ch) == -EAGAIN)
WATCHDOG_RESET();
}
DEBUG_UART_FUNCS
#endif
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