[U-Boot] [PATCH 3/5] serial: add support for Amlogic Meson UART
Beniamino Galvani
b.galvani at gmail.com
Sun Mar 27 22:22:13 CEST 2016
Implement a driver for the UART adapter available in Meson SoCs.
Signed-off-by: Beniamino Galvani <b.galvani at 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 05bdf56..8eb0ca2 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..550b8a5
--- /dev/null
+++ b/drivers/serial/serial_meson.c
@@ -0,0 +1,162 @@
+/*
+ * (C) Copyright 2016 Beniamino Galvani <b.galvani at 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,
+ .ofdata_to_platdata = meson_serial_ofdata_to_platdata,
+ .platdata_auto_alloc_size = sizeof(struct meson_serial_platdata),
+ .probe = meson_serial_probe,
+ .ops = &meson_serial_ops,
+ .flags = DM_FLAG_PRE_RELOC,
+};
+
+#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
--
2.4.3
More information about the U-Boot
mailing list