altera_uart.c
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// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2004, Psyent Corporation <www.psyent.com>
* Scott McNutt <smcnutt@psyent.com>
*/
#include <common.h>
#include <dm.h>
#include <errno.h>
#include <serial.h>
#include <asm/io.h>
/* status register */
#define ALTERA_UART_TMT BIT(5) /* tx empty */
#define ALTERA_UART_TRDY BIT(6) /* tx ready */
#define ALTERA_UART_RRDY BIT(7) /* rx ready */
struct altera_uart_regs {
u32 rxdata; /* Rx data reg */
u32 txdata; /* Tx data reg */
u32 status; /* Status reg */
u32 control; /* Control reg */
u32 divisor; /* Baud rate divisor reg */
u32 endofpacket; /* End-of-packet reg */
};
struct altera_uart_platdata {
struct altera_uart_regs *regs;
unsigned int uartclk;
};
static int altera_uart_setbrg(struct udevice *dev, int baudrate)
{
struct altera_uart_platdata *plat = dev->platdata;
struct altera_uart_regs *const regs = plat->regs;
u32 div;
div = (plat->uartclk / baudrate) - 1;
writel(div, ®s->divisor);
return 0;
}
static int altera_uart_putc(struct udevice *dev, const char ch)
{
struct altera_uart_platdata *plat = dev->platdata;
struct altera_uart_regs *const regs = plat->regs;
if (!(readl(®s->status) & ALTERA_UART_TRDY))
return -EAGAIN;
writel(ch, ®s->txdata);
return 0;
}
static int altera_uart_pending(struct udevice *dev, bool input)
{
struct altera_uart_platdata *plat = dev->platdata;
struct altera_uart_regs *const regs = plat->regs;
u32 st = readl(®s->status);
if (input)
return st & ALTERA_UART_RRDY ? 1 : 0;
else
return !(st & ALTERA_UART_TMT);
}
static int altera_uart_getc(struct udevice *dev)
{
struct altera_uart_platdata *plat = dev->platdata;
struct altera_uart_regs *const regs = plat->regs;
if (!(readl(®s->status) & ALTERA_UART_RRDY))
return -EAGAIN;
return readl(®s->rxdata) & 0xff;
}
static int altera_uart_probe(struct udevice *dev)
{
return 0;
}
static int altera_uart_ofdata_to_platdata(struct udevice *dev)
{
struct altera_uart_platdata *plat = dev_get_platdata(dev);
plat->regs = map_physmem(devfdt_get_addr(dev),
sizeof(struct altera_uart_regs),
MAP_NOCACHE);
plat->uartclk = dev_read_u32_default(dev, "clock-frequency", 0);
return 0;
}
static const struct dm_serial_ops altera_uart_ops = {
.putc = altera_uart_putc,
.pending = altera_uart_pending,
.getc = altera_uart_getc,
.setbrg = altera_uart_setbrg,
};
static const struct udevice_id altera_uart_ids[] = {
{ .compatible = "altr,uart-1.0" },
{}
};
U_BOOT_DRIVER(altera_uart) = {
.name = "altera_uart",
.id = UCLASS_SERIAL,
.of_match = altera_uart_ids,
.ofdata_to_platdata = altera_uart_ofdata_to_platdata,
.platdata_auto_alloc_size = sizeof(struct altera_uart_platdata),
.probe = altera_uart_probe,
.ops = &altera_uart_ops,
};
#ifdef CONFIG_DEBUG_UART_ALTERA_UART
#include <debug_uart.h>
static inline void _debug_uart_init(void)
{
struct altera_uart_regs *regs = (void *)CONFIG_DEBUG_UART_BASE;
u32 div;
div = (CONFIG_DEBUG_UART_CLOCK / CONFIG_BAUDRATE) - 1;
writel(div, ®s->divisor);
}
static inline void _debug_uart_putc(int ch)
{
struct altera_uart_regs *regs = (void *)CONFIG_DEBUG_UART_BASE;
while (1) {
u32 st = readl(®s->status);
if (st & ALTERA_UART_TRDY)
break;
}
writel(ch, ®s->txdata);
}
DEBUG_UART_FUNCS
#endif