Implement a driver for the UART adapter available in Meson SoCs.
Signed-off-by: Beniamino Galvani b.galvani@gmail.com --- drivers/serial/Kconfig | 14 ++++ drivers/serial/Makefile | 1 + drivers/serial/serial_meson.c | 162 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 177 insertions(+) create mode 100644 drivers/serial/serial_meson.c
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig index 2a770a1..47e26ab 100644 --- a/drivers/serial/Kconfig +++ b/drivers/serial/Kconfig @@ -112,6 +112,14 @@ config DEBUG_UART_S5P will need to provide parameters to make this work. The driver will be available until the real driver-model serial is running.
+config DEBUG_UART_MESON + bool "Amlogic Meson" + depends on MESON_SERIAL + help + Select this to enable a debug UART using the serial_meson driver. You + will need to provide parameters to make this work. The driver will + be available until the real driver-model serial is running. + config DEBUG_UART_UARTLITE bool "Xilinx Uartlite" help @@ -320,4 +328,10 @@ config XILINX_UARTLITE If you have a Xilinx based board and want to use the uartlite serial ports, say Y to this option. If unsure, say N.
+config MESON_SERIAL + bool "Support for Amlogic Meson UART" + depends on DM_SERIAL && ARCH_MESON + help + If you have an Amlogic Meson based board and want to use the on-chip + serial ports, say Y to this option. If unsure, say N. endmenu diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile index ee7147a..4fe1eb3 100644 --- a/drivers/serial/Makefile +++ b/drivers/serial/Makefile @@ -26,6 +26,7 @@ obj-$(CONFIG_SYS_NS16550) += ns16550.o obj-$(CONFIG_S5P) += serial_s5p.o obj-$(CONFIG_MXC_UART) += serial_mxc.o obj-$(CONFIG_PXA_SERIAL) += serial_pxa.o +obj-$(CONFIG_MESON_SERIAL) += serial_meson.o obj-$(CONFIG_S3C24X0_SERIAL) += serial_s3c24x0.o obj-$(CONFIG_XILINX_UARTLITE) += serial_xuartlite.o obj-$(CONFIG_SANDBOX_SERIAL) += sandbox.o diff --git a/drivers/serial/serial_meson.c b/drivers/serial/serial_meson.c new file mode 100644 index 0000000..140b2d4 --- /dev/null +++ b/drivers/serial/serial_meson.c @@ -0,0 +1,162 @@ +/* + * (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 { + uint32_t wfifo; + uint32_t rfifo; + uint32_t control; + uint32_t status; + uint32_t 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 __maybe_unused 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 = dev_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