This patch adds uart support for MediaTek MT7620 and earlier SoCs.
The UART used by MT7620 is incompatible with the ns16550a driver. All registers of this UART have different addresses. A special 16-bit register for Divisor Latch is used to set the baudrate instead of the original two 8-bit registers (DLL and DLM).
The driver supports of-platdata which is useful for tiny SPL.
Reviewed-by: Stefan Roese sr@denx.de Reviewed-by: Simon Glass sjg@chromium.org Signed-off-by: Weijie Gao weijie.gao@mediatek.com --- v4 changes: remove unused non-DM code in drivers/serial/serial.c v3 changes: none v2 changes: replace non-DM code with of-platdata --- drivers/serial/Kconfig | 20 +++ drivers/serial/Makefile | 1 + drivers/serial/serial_mt7620.c | 246 +++++++++++++++++++++++++++++++++ 3 files changed, 267 insertions(+) create mode 100644 drivers/serial/serial_mt7620.c
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig index b4805a2e4e..44fff8a3cd 100644 --- a/drivers/serial/Kconfig +++ b/drivers/serial/Kconfig @@ -401,6 +401,16 @@ config DEBUG_UART_MTK driver will be available until the real driver model serial is running.
+config DEBUG_UART_MT7620 + bool "UART driver for MediaTek MT7620 and earlier SoCs" + depends on MT7620_SERIAL + help + Select this to enable a debug UART using the UART driver for + MediaTek MT7620 and earlier SoCs. + You will need to provide parameters to make this work. The + driver will be available until the real driver model serial is + running. + endchoice
config DEBUG_UART_BASE @@ -817,6 +827,16 @@ config MTK_SERIAL The High-speed UART is compatible with the ns16550a UART and have its own high-speed registers.
+config MT7620_SERIAL + bool "UART driver for MediaTek MT7620 and earlier SoCs" + depends on DM_SERIAL + help + Select this to enable UART support for MediaTek MT7620 and earlier + SoCs. This driver uses driver model and requires a device tree + binding to operate. + The UART driver for MediaTek MT7620 and earlier SoCs is *NOT* + compatible with the ns16550a UART. + config MPC8XX_CONS bool "Console driver for MPC8XX" depends on MPC8xx diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile index 25f7f8d342..0c3810f5d5 100644 --- a/drivers/serial/Makefile +++ b/drivers/serial/Makefile @@ -69,6 +69,7 @@ obj-$(CONFIG_NULLDEV_SERIAL) += serial_nulldev.o obj-$(CONFIG_OWL_SERIAL) += serial_owl.o obj-$(CONFIG_OMAP_SERIAL) += serial_omap.o obj-$(CONFIG_MTK_SERIAL) += serial_mtk.o +obj-$(CONFIG_MT7620_SERIAL) += serial_mt7620.o obj-$(CONFIG_SIFIVE_SERIAL) += serial_sifive.o obj-$(CONFIG_XEN_SERIAL) += serial_xen.o
diff --git a/drivers/serial/serial_mt7620.c b/drivers/serial/serial_mt7620.c new file mode 100644 index 0000000000..4f6b5de4cf --- /dev/null +++ b/drivers/serial/serial_mt7620.c @@ -0,0 +1,246 @@ +// 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_platdata(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_platdata(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_platdata(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_platdata(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_platdata(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_PLATDATA) +static int mt7620_serial_ofdata_to_platdata(struct udevice *dev) +{ + struct mt7620_serial_plat *plat = dev_get_platdata(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_PLATDATA) + .of_match = mt7620_serial_ids, + .ofdata_to_platdata = mt7620_serial_ofdata_to_platdata, +#endif + .platdata_auto_alloc_size = sizeof(struct mt7620_serial_plat), + .probe = mt7620_serial_probe, + .ops = &mt7620_serial_ops, + .flags = DM_FLAG_PRE_RELOC, +}; + +U_BOOT_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_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_DEBUG_UART_BASE; + + while (!(readl(®s->lsr) & UART_LSR_THRE)) + ; + + writel(ch, ®s->thr); +} + +DEBUG_UART_FUNCS + +#endif