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/*
* (C) Copyright 2009 SAMSUNG Electronics
* Minkyu Kang <mk7.kang@samsung.com>
* Heungjun Kim <riverful.kim@samsung.com>
*
* based on drivers/serial/s3c64xx.c
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <dm.h>
#include <errno.h>
#include <fdtdec.h>
#include <linux/compiler.h>
#include <asm/io.h>
#include <asm/arch/uart.h>
#include <asm/arch/clk.h>
#include <serial.h>
DECLARE_GLOBAL_DATA_PTR;
#define RX_FIFO_COUNT_SHIFT 0
#define RX_FIFO_COUNT_MASK (0xff << RX_FIFO_COUNT_SHIFT)
#define RX_FIFO_FULL (1 << 8)
#define TX_FIFO_COUNT_SHIFT 16
#define TX_FIFO_COUNT_MASK (0xff << TX_FIFO_COUNT_SHIFT)
#define TX_FIFO_FULL (1 << 24)
/* Information about a serial port */
struct s5p_serial_platdata {
struct s5p_uart *reg; /* address of registers in physical memory */
u8 port_id; /* uart port number */
};
/*
* The coefficient, used to calculate the baudrate on S5P UARTs is
* calculated as
* C = UBRDIV * 16 + number_of_set_bits_in_UDIVSLOT
* however, section 31.6.11 of the datasheet doesn't recomment using 1 for 1,
* 3 for 2, ... (2^n - 1) for n, instead, they suggest using these constants:
*/
static const int udivslot[] = {
0,
0x0080,
0x0808,
0x0888,
0x2222,
0x4924,
0x4a52,
0x54aa,
0x5555,
0xd555,
0xd5d5,
0xddd5,
0xdddd,
0xdfdd,
0xdfdf,
0xffdf,
};
int s5p_serial_setbrg(struct udevice *dev, int baudrate)
{
struct s5p_serial_platdata *plat = dev->platdata;
struct s5p_uart *const uart = plat->reg;
u32 uclk = get_uart_clk(plat->port_id);
u32 val;
val = uclk / baudrate;
writel(val / 16 - 1, &uart->ubrdiv);
if (s5p_uart_divslot())
writew(udivslot[val % 16], &uart->rest.slot);
else
writeb(val % 16, &uart->rest.value);
return 0;
}
static int s5p_serial_probe(struct udevice *dev)
{
struct s5p_serial_platdata *plat = dev->platdata;
struct s5p_uart *const uart = plat->reg;
/* enable FIFOs, auto clear Rx FIFO */
writel(0x3, &uart->ufcon);
writel(0, &uart->umcon);
/* 8N1 */
writel(0x3, &uart->ulcon);
/* No interrupts, no DMA, pure polling */
writel(0x245, &uart->ucon);
return 0;
}
static int serial_err_check(const struct s5p_uart *const uart, int op)
{
unsigned int mask;
/*
* UERSTAT
* Break Detect [3]
* Frame Err [2] : receive operation
* Parity Err [1] : receive operation
* Overrun Err [0] : receive operation
*/
if (op)
mask = 0x8;
else
mask = 0xf;
return readl(&uart->uerstat) & mask;
}
static int s5p_serial_getc(struct udevice *dev)
{
struct s5p_serial_platdata *plat = dev->platdata;
struct s5p_uart *const uart = plat->reg;
if (!(readl(&uart->ufstat) & RX_FIFO_COUNT_MASK))
return -EAGAIN;
serial_err_check(uart, 0);
return (int)(readb(&uart->urxh) & 0xff);
}
static int s5p_serial_putc(struct udevice *dev, const char ch)
{
struct s5p_serial_platdata *plat = dev->platdata;
struct s5p_uart *const uart = plat->reg;
if (readl(&uart->ufstat) & TX_FIFO_FULL)
return -EAGAIN;
writeb(ch, &uart->utxh);
serial_err_check(uart, 1);
return 0;
}
static int s5p_serial_pending(struct udevice *dev, bool input)
{
struct s5p_serial_platdata *plat = dev->platdata;
struct s5p_uart *const uart = plat->reg;
uint32_t ufstat = readl(&uart->ufstat);
if (input)
return (ufstat & RX_FIFO_COUNT_MASK) >> RX_FIFO_COUNT_SHIFT;
else
return (ufstat & TX_FIFO_COUNT_MASK) >> TX_FIFO_COUNT_SHIFT;
}
static int s5p_serial_ofdata_to_platdata(struct udevice *dev)
{
struct s5p_serial_platdata *plat = dev->platdata;
fdt_addr_t addr;
addr = fdtdec_get_addr(gd->fdt_blob, dev->of_offset, "reg");
if (addr == FDT_ADDR_T_NONE)
return -EINVAL;
plat->reg = (struct s5p_uart *)addr;
plat->port_id = fdtdec_get_int(gd->fdt_blob, dev->of_offset, "id", -1);
return 0;
}
static const struct dm_serial_ops s5p_serial_ops = {
.putc = s5p_serial_putc,
.pending = s5p_serial_pending,
.getc = s5p_serial_getc,
.setbrg = s5p_serial_setbrg,
};
static const struct udevice_id s5p_serial_ids[] = {
{ .compatible = "samsung,exynos4210-uart" },
{ }
};
U_BOOT_DRIVER(serial_s5p) = {
.name = "serial_s5p",
.id = UCLASS_SERIAL,
.of_match = s5p_serial_ids,
.ofdata_to_platdata = s5p_serial_ofdata_to_platdata,
.platdata_auto_alloc_size = sizeof(struct s5p_serial_platdata),
.probe = s5p_serial_probe,
.ops = &s5p_serial_ops,
.flags = DM_FLAG_PRE_RELOC,
};
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