serial_meson.c
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/*
* (C) Copyright 2016 Beniamino Galvani <b.galvani@gmail.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <dm.h>
#include <errno.h>
#include <fdtdec.h>
#include <linux/compiler.h>
#include <serial.h>
DECLARE_GLOBAL_DATA_PTR;
struct meson_uart {
u32 wfifo;
u32 rfifo;
u32 control;
u32 status;
u32 misc;
};
struct meson_serial_platdata {
struct meson_uart *reg;
};
/* AML_UART_STATUS bits */
#define AML_UART_PARITY_ERR BIT(16)
#define AML_UART_FRAME_ERR BIT(17)
#define AML_UART_TX_FIFO_WERR BIT(18)
#define AML_UART_RX_EMPTY BIT(20)
#define AML_UART_TX_FULL BIT(21)
#define AML_UART_TX_EMPTY BIT(22)
#define AML_UART_XMIT_BUSY BIT(25)
#define AML_UART_ERR (AML_UART_PARITY_ERR | \
AML_UART_FRAME_ERR | \
AML_UART_TX_FIFO_WERR)
/* AML_UART_CONTROL bits */
#define AML_UART_TX_EN BIT(12)
#define AML_UART_RX_EN BIT(13)
#define AML_UART_TX_RST BIT(22)
#define AML_UART_RX_RST BIT(23)
#define AML_UART_CLR_ERR BIT(24)
static void meson_serial_init(struct meson_uart *uart)
{
u32 val;
val = readl(&uart->control);
val |= (AML_UART_RX_RST | AML_UART_TX_RST | AML_UART_CLR_ERR);
writel(val, &uart->control);
val &= ~(AML_UART_RX_RST | AML_UART_TX_RST | AML_UART_CLR_ERR);
writel(val, &uart->control);
val |= (AML_UART_RX_EN | AML_UART_TX_EN);
writel(val, &uart->control);
}
static int meson_serial_probe(struct udevice *dev)
{
struct meson_serial_platdata *plat = dev->platdata;
struct meson_uart *const uart = plat->reg;
meson_serial_init(uart);
return 0;
}
static int meson_serial_getc(struct udevice *dev)
{
struct meson_serial_platdata *plat = dev->platdata;
struct meson_uart *const uart = plat->reg;
if (readl(&uart->status) & AML_UART_RX_EMPTY)
return -EAGAIN;
return readl(&uart->rfifo) & 0xff;
}
static int meson_serial_putc(struct udevice *dev, const char ch)
{
struct meson_serial_platdata *plat = dev->platdata;
struct meson_uart *const uart = plat->reg;
if (readl(&uart->status) & AML_UART_TX_FULL)
return -EAGAIN;
writel(ch, &uart->wfifo);
return 0;
}
static int meson_serial_pending(struct udevice *dev, bool input)
{
struct meson_serial_platdata *plat = dev->platdata;
struct meson_uart *const uart = plat->reg;
uint32_t status = readl(&uart->status);
if (input)
return !(status & AML_UART_RX_EMPTY);
else
return !(status & AML_UART_TX_FULL);
}
static int meson_serial_ofdata_to_platdata(struct udevice *dev)
{
struct meson_serial_platdata *plat = dev->platdata;
fdt_addr_t addr;
addr = devfdt_get_addr(dev);
if (addr == FDT_ADDR_T_NONE)
return -EINVAL;
plat->reg = (struct meson_uart *)addr;
return 0;
}
static const struct dm_serial_ops meson_serial_ops = {
.putc = meson_serial_putc,
.pending = meson_serial_pending,
.getc = meson_serial_getc,
};
static const struct udevice_id meson_serial_ids[] = {
{ .compatible = "amlogic,meson-uart" },
{ }
};
U_BOOT_DRIVER(serial_meson) = {
.name = "serial_meson",
.id = UCLASS_SERIAL,
.of_match = meson_serial_ids,
.probe = meson_serial_probe,
.ops = &meson_serial_ops,
.flags = DM_FLAG_PRE_RELOC,
.ofdata_to_platdata = meson_serial_ofdata_to_platdata,
.platdata_auto_alloc_size = sizeof(struct meson_serial_platdata),
};
#ifdef CONFIG_DEBUG_UART_MESON
#include <debug_uart.h>
static inline void _debug_uart_init(void)
{
}
static inline void _debug_uart_putc(int ch)
{
struct meson_uart *regs = (struct meson_uart *)CONFIG_DEBUG_UART_BASE;
while (readl(®s->status) & AML_UART_TX_FULL)
;
writel(ch, ®s->wfifo);
}
DEBUG_UART_FUNCS
#endif