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// SPDX-License-Identifier: GPL-2.0
/*
* UART driver for MediaTek MT7620 and earlier SoCs
*
* Copyright (C) 2020 MediaTek Inc.
* Author: Weijie Gao <weijie.gao@mediatek.com>
*/
#include <clk.h>
#include <div64.h>
#include <dm.h>
#include <errno.h>
#include <log.h>
#include <reset.h>
#include <serial.h>
#include <watchdog.h>
#include <asm/io.h>
#include <asm/types.h>
#include <asm/addrspace.h>
#include <dm/device_compat.h>
#include <linux/err.h>
#if CONFIG_IS_ENABLED(OF_PLATDATA)
#include <dt-structs.h>
#endif
struct mt7620_serial_regs {
u32 rbr;
u32 thr;
u32 ier;
u32 iir;
u32 fcr;
u32 lcr;
u32 mcr;
u32 lsr;
u32 msr;
u32 scratch;
u32 dl;
u32 dll;
u32 dlm;
u32 ifctl;
};
#define UART_LCR_WLS_8 0x03 /* 8 bit character length */
#define UART_LSR_DR 0x01 /* Data ready */
#define UART_LSR_THRE 0x20 /* Xmit holding register empty */
#define UART_LSR_TEMT 0x40 /* Xmitter empty */
#define UART_MCR_DTR 0x01 /* DTR */
#define UART_MCR_RTS 0x02 /* RTS */
#define UART_FCR_FIFO_EN 0x01 /* Fifo enable */
#define UART_FCR_RXSR 0x02 /* Receiver soft reset */
#define UART_FCR_TXSR 0x04 /* Transmitter soft reset */
#define UART_MCRVAL (UART_MCR_DTR | \
UART_MCR_RTS)
/* Clear & enable FIFOs */
#define UART_FCRVAL (UART_FCR_FIFO_EN | \
UART_FCR_RXSR | \
UART_FCR_TXSR)
struct mt7620_serial_plat {
#if CONFIG_IS_ENABLED(OF_PLATDATA)
struct dtd_serial_mt7620 dtplat;
#endif
struct mt7620_serial_regs __iomem *regs;
u32 clock;
};
static void _mt7620_serial_setbrg(struct mt7620_serial_plat *plat, int baud)
{
u32 quot;
/* set divisor */
quot = DIV_ROUND_CLOSEST(plat->clock, 16 * baud);
writel(quot, &plat->regs->dl);
/* set character length and stop bits */
writel(UART_LCR_WLS_8, &plat->regs->lcr);
}
static int mt7620_serial_setbrg(struct udevice *dev, int baudrate)
{
struct mt7620_serial_plat *plat = dev_get_plat(dev);
_mt7620_serial_setbrg(plat, baudrate);
return 0;
}
static int mt7620_serial_putc(struct udevice *dev, const char ch)
{
struct mt7620_serial_plat *plat = dev_get_plat(dev);
if (!(readl(&plat->regs->lsr) & UART_LSR_THRE))
return -EAGAIN;
writel(ch, &plat->regs->thr);
if (ch == '\n')
WATCHDOG_RESET();
return 0;
}
static int mt7620_serial_getc(struct udevice *dev)
{
struct mt7620_serial_plat *plat = dev_get_plat(dev);
if (!(readl(&plat->regs->lsr) & UART_LSR_DR))
return -EAGAIN;
return readl(&plat->regs->rbr);
}
static int mt7620_serial_pending(struct udevice *dev, bool input)
{
struct mt7620_serial_plat *plat = dev_get_plat(dev);
if (input)
return (readl(&plat->regs->lsr) & UART_LSR_DR) ? 1 : 0;
return (readl(&plat->regs->lsr) & UART_LSR_THRE) ? 0 : 1;
}
static int mt7620_serial_probe(struct udevice *dev)
{
struct mt7620_serial_plat *plat = dev_get_plat(dev);
#if CONFIG_IS_ENABLED(OF_PLATDATA)
plat->regs = (void __iomem *)KSEG1ADDR(plat->dtplat.reg[0]);
plat->clock = plat->dtplat.clock_frequency;
#endif
/* Disable interrupt */
writel(0, &plat->regs->ier);
writel(UART_MCRVAL, &plat->regs->mcr);
writel(UART_FCRVAL, &plat->regs->fcr);
return 0;
}
#if CONFIG_IS_ENABLED(OF_REAL)
static int mt7620_serial_of_to_plat(struct udevice *dev)
{
struct mt7620_serial_plat *plat = dev_get_plat(dev);
struct reset_ctl reset_uart;
struct clk clk;
int err;
err = reset_get_by_index(dev, 0, &reset_uart);
if (!err)
reset_deassert(&reset_uart);
plat->regs = dev_remap_addr_index(dev, 0);
if (!plat->regs) {
dev_err(dev, "mt7620_serial: unable to map UART registers\n");
return -EINVAL;
}
err = clk_get_by_index(dev, 0, &clk);
if (!err) {
err = clk_get_rate(&clk);
if (!IS_ERR_VALUE(err))
plat->clock = err;
} else if (err != -ENOENT && err != -ENODEV && err != -ENOSYS) {
dev_err(dev, "mt7620_serial: failed to get clock\n");
return err;
}
if (!plat->clock)
plat->clock = dev_read_u32_default(dev, "clock-frequency", 0);
if (!plat->clock) {
dev_err(dev, "mt7620_serial: clock not defined\n");
return -EINVAL;
}
return 0;
}
static const struct udevice_id mt7620_serial_ids[] = {
{ .compatible = "mediatek,mt7620-uart" },
{ }
};
#endif
static const struct dm_serial_ops mt7620_serial_ops = {
.putc = mt7620_serial_putc,
.pending = mt7620_serial_pending,
.getc = mt7620_serial_getc,
.setbrg = mt7620_serial_setbrg,
};
U_BOOT_DRIVER(serial_mt7620) = {
.name = "serial_mt7620",
.id = UCLASS_SERIAL,
#if CONFIG_IS_ENABLED(OF_REAL)
.of_match = mt7620_serial_ids,
.of_to_plat = mt7620_serial_of_to_plat,
#endif
.plat_auto = sizeof(struct mt7620_serial_plat),
.probe = mt7620_serial_probe,
.ops = &mt7620_serial_ops,
.flags = DM_FLAG_PRE_RELOC,
};
DM_DRIVER_ALIAS(serial_mt7620, mediatek_mt7620_uart);
#ifdef CONFIG_DEBUG_UART_MT7620
#include <debug_uart.h>
static inline void _debug_uart_init(void)
{
struct mt7620_serial_plat plat;
plat.regs = (void *)CONFIG_VAL(DEBUG_UART_BASE);
plat.clock = CONFIG_DEBUG_UART_CLOCK;
writel(0, &plat.regs->ier);
writel(UART_MCRVAL, &plat.regs->mcr);
writel(UART_FCRVAL, &plat.regs->fcr);
_mt7620_serial_setbrg(&plat, CONFIG_BAUDRATE);
}
static inline void _debug_uart_putc(int ch)
{
struct mt7620_serial_regs __iomem *regs =
(void *)CONFIG_VAL(DEBUG_UART_BASE);
while (!(readl(&regs->lsr) & UART_LSR_THRE))
;
writel(ch, &regs->thr);
}
DEBUG_UART_FUNCS
#endif