[U-Boot] [PATCH v6 05/10] mips: ath79: add serial driver for ar933x SOC

Wills Wang
2016-01-04T11:14:56Z

Signed-off-by: Wills Wang <wills.wang@live.com>
---

Changes in v6:
- Remove wait loop in putc and getc
- Use map_physmem instead of KSEG1ADDR

Changes in v5:
- remove ar933x_serial_platdata
- Import document "qca,ar9330-uart.txt" from kernel
- Add support for debug UART

Changes in v4:
- Auto calculate baudrate for serial driver
- Move pinctrl code in serial driver into arch/mips/mach-ath79
- Use get_serial_clock to serial clock source

Changes in v3:
- Convert serial driver to driver model
- Same code style convertion

Changes in v2:
- Move serial driver code into drivers/serial

.../serial/qca,ar9330-uart.txt | 24 ++
drivers/serial/Kconfig | 17 ++
drivers/serial/Makefile | 1 +
drivers/serial/serial_ar933x.c | 264 +++++++++++++++++++++
4 files changed, 306 insertions(+)
create mode 100644 doc/device-tree-bindings/serial/qca,ar9330-uart.txt
create mode 100644 drivers/serial/serial_ar933x.c

diff --git a/doc/device-tree-bindings/serial/qca,ar9330-uart.txt b/doc/device-tree-bindings/serial/qca,ar9330-uart.txt
new file mode 100644
index 0000000..ec576a1
--- /dev/null
+++ b/doc/device-tree-bindings/serial/qca,ar9330-uart.txt
@@ -0,0 +1,24 @@
+* Qualcomm Atheros AR9330 High-Speed UART
+
+Required properties:
+
+- compatible: Must be "qca,ar9330-uart"
+
+- reg: Specifies the physical base address of the controller and
+ the length of the memory mapped region.
+
+Additional requirements:
+
+ Each UART port must have an alias correctly numbered in "aliases"
+ node.
+
+Example:
+
+ aliases {
+ serial0 = &uart0;
+ };
+
+ uart0: uart at 18020000 {
+ compatible = "qca,ar9330-uart";
+ reg = <0x18020000 0x14>;
+ };
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 1fc287e..f147379 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -69,6 +69,14 @@ config DEBUG_UART_ALTERA_UART
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_AR933X
+ bool "QCA/Atheros ar933x"
+ help
+ Select this to enable a debug UART using the ar933x uart 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_NS16550
bool "ns16550"
help
@@ -186,6 +194,15 @@ config ALTERA_UART
Select this to enable an UART for Altera devices. Please find
details on the "Embedded Peripherals IP User Guide" of Altera.

+config AR933X_UART
+ bool "QCA/Atheros ar933x UART support"
+ depends on DM_SERIAL
+ help
+ Select this to enable UART support for QCA/Atheros ar933x
+ devices. This driver uses driver model and requires a device
+ tree binding to operate, please refer to the document at
+ doc/device-tree-bindings/serial/qca,ar9330-uart.txt.
+
config SYS_NS16550
bool "NS16550 UART or compatible"
help
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index dd87147..b7b82ae 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -17,6 +17,7 @@ endif

obj-$(CONFIG_ALTERA_UART) += altera_uart.o
obj-$(CONFIG_ALTERA_JTAG_UART) += altera_jtag_uart.o
+obj-$(CONFIG_AR933X_UART) += serial_ar933x.o
obj-$(CONFIG_ARM_DCC) += arm_dcc.o
obj-$(CONFIG_ATMEL_USART) += atmel_usart.o
obj-$(CONFIG_EFI_APP) += serial_efi.o
diff --git a/drivers/serial/serial_ar933x.c b/drivers/serial/serial_ar933x.c
new file mode 100644
index 0000000..38d34c2
--- /dev/null
+++ b/drivers/serial/serial_ar933x.c
@@ -0,0 +1,264 @@
+/*
+ * (C) Copyright 2015
+ * Wills Wang, <wills.wang@live.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <div64.h>
+#include <errno.h>
+#include <serial.h>
+#include <asm/io.h>
+#include <asm/addrspace.h>
+#include <asm/types.h>
+#include <mach/ar71xx_regs.h>
+
+#define AR933X_UART_DATA_REG 0x00
+#define AR933X_UART_CS_REG 0x04
+#define AR933X_UART_CLK_REG 0x08
+
+#define AR933X_UART_DATA_TX_RX_MASK 0xff
+#define AR933X_UART_DATA_RX_CSR BIT(8)
+#define AR933X_UART_DATA_TX_CSR BIT(9)
+#define AR933X_UART_CS_IF_MODE_S 2
+#define AR933X_UART_CS_IF_MODE_M 0x3
+#define AR933X_UART_CS_IF_MODE_DTE 1
+#define AR933X_UART_CS_IF_MODE_DCE 2
+#define AR933X_UART_CS_TX_RDY_ORIDE BIT(7)
+#define AR933X_UART_CS_RX_RDY_ORIDE BIT(8)
+#define AR933X_UART_CLK_STEP_M 0xffff
+#define AR933X_UART_CLK_SCALE_M 0xfff
+#define AR933X_UART_CLK_SCALE_S 16
+#define AR933X_UART_CLK_STEP_S 0
+
+struct ar933x_serial_priv {
+ void __iomem *regs;
+};
+
+static inline u32 ar933x_serial_read(struct udevice *dev, u32 offset)
+{
+ struct ar933x_serial_priv *priv = dev_get_priv(dev);
+
+ return readl(priv->regs + offset);
+}
+
+static inline void ar933x_serial_write(struct udevice *dev,
+ u32 val, u32 offset)
+{
+ struct ar933x_serial_priv *priv = dev_get_priv(dev);
+
+ writel(val, priv->regs + offset);
+}
+
+/*
+ * baudrate = (clk / (scale + 1)) * (step * (1 / 2^17))
+ */
+static u32 ar933x_serial_get_baud(u32 clk, u32 scale, u32 step)
+{
+ u64 t;
+ u32 div;
+
+ div = (2 << 16) * (scale + 1);
+ t = clk;
+ t *= step;
+ t += (div / 2);
+ do_div(t, div);
+
+ return t;
+}
+
+static void ar933x_serial_get_scale_step(u32 clk, u32 baud,
+ u32 *scale, u32 *step)
+{
+ u32 tscale, baudrate;
+ long min_diff;
+
+ *scale = 0;
+ *step = 0;
+
+ min_diff = baud;
+ for (tscale = 0; tscale < AR933X_UART_CLK_SCALE_M; tscale++) {
+ u64 tstep;
+ int diff;
+
+ tstep = baud * (tscale + 1);
+ tstep *= (2 << 16);
+ do_div(tstep, clk);
+
+ if (tstep > AR933X_UART_CLK_STEP_M)
+ break;
+
+ baudrate = ar933x_serial_get_baud(clk, tscale, tstep);
+ diff = abs(baudrate - baud);
+ if (diff < min_diff) {
+ min_diff = diff;
+ *scale = tscale;
+ *step = tstep;
+ }
+ }
+}
+
+static int ar933x_serial_setbrg(struct udevice *dev, int baudrate)
+{
+ u32 val, scale, step;
+
+ val = get_serial_clock();
+ ar933x_serial_get_scale_step(val, baudrate, &scale, &step);
+
+ val = (scale & AR933X_UART_CLK_SCALE_M)
+ << AR933X_UART_CLK_SCALE_S;
+ val |= (step & AR933X_UART_CLK_STEP_M)
+ << AR933X_UART_CLK_STEP_S;
+ ar933x_serial_write(dev, val, AR933X_UART_CLK_REG);
+
+ return 0;
+}
+
+static int ar933x_serial_putc(struct udevice *dev, const char c)
+{
+ u32 data;
+
+ data = ar933x_serial_read(dev, AR933X_UART_DATA_REG);
+ if (!(data & AR933X_UART_DATA_TX_CSR))
+ return -EAGAIN;
+
+ data = (u32)c | AR933X_UART_DATA_TX_CSR;
+ ar933x_serial_write(dev, data, AR933X_UART_DATA_REG);
+
+ return 0;
+}
+
+static int ar933x_serial_getc(struct udevice *dev)
+{
+ u32 data;
+
+ data = ar933x_serial_read(dev, AR933X_UART_DATA_REG);
+ if (!(data & AR933X_UART_DATA_RX_CSR))
+ return -EAGAIN;
+
+ data = ar933x_serial_read(dev, AR933X_UART_DATA_REG);
+ ar933x_serial_write(dev, AR933X_UART_DATA_RX_CSR,
+ AR933X_UART_DATA_REG);
+ return data & AR933X_UART_DATA_TX_RX_MASK;
+}
+
+static int ar933x_serial_pending(struct udevice *dev, bool input)
+{
+ u32 data;
+
+ data = ar933x_serial_read(dev, AR933X_UART_DATA_REG);
+ if (input)
+ return (data & AR933X_UART_DATA_RX_CSR) ? 1 : 0;
+ else
+ return (data & AR933X_UART_DATA_TX_CSR) ? 0 : 1;
+}
+
+static int ar933x_serial_probe(struct udevice *dev)
+{
+ struct ar933x_serial_priv *priv = dev_get_priv(dev);
+ u32 val;
+ fdt_addr_t addr;
+
+ addr = dev_get_addr(dev);
+ if (addr == FDT_ADDR_T_NONE)
+ return -EINVAL;
+
+ priv->regs = map_physmem(addr,
+ AR933X_UART_SIZE,
+ MAP_NOCACHE);
+
+ /*
+ * UART controller configuration:
+ * - no DMA
+ * - no interrupt
+ * - DCE mode
+ * - no flow control
+ * - set RX ready oride
+ * - set TX ready oride
+ */
+ val = (AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S) |
+ AR933X_UART_CS_TX_RDY_ORIDE | AR933X_UART_CS_RX_RDY_ORIDE;
+ ar933x_serial_write(dev, val, AR933X_UART_CS_REG);
+ return 0;
+}
+
+static const struct dm_serial_ops ar933x_serial_ops = {
+ .putc = ar933x_serial_putc,
+ .pending = ar933x_serial_pending,
+ .getc = ar933x_serial_getc,
+ .setbrg = ar933x_serial_setbrg,
+};
+
+static const struct udevice_id ar933x_serial_ids[] = {
+ { .compatible = "qca,ar9330-uart" },
+ { }
+};
+
+U_BOOT_DRIVER(serial_ar933x) = {
+ .name = "serial_ar933x",
+ .id = UCLASS_SERIAL,
+ .of_match = ar933x_serial_ids,
+ .priv_auto_alloc_size = sizeof(struct ar933x_serial_priv),
+ .probe = ar933x_serial_probe,
+ .ops = &ar933x_serial_ops,
+ .flags = DM_FLAG_PRE_RELOC,
+};
+
+#ifdef CONFIG_DEBUG_UART_AR933X
+
+#include <debug_uart.h>
+
+static inline void _debug_uart_init(void)
+{
+ void __iomem *regs;
+ u32 val, scale, step;
+
+ regs = map_physmem(CONFIG_DEBUG_UART_BASE,
+ AR933X_UART_SIZE,
+ MAP_NOCACHE);
+
+ /*
+ * UART controller configuration:
+ * - no DMA
+ * - no interrupt
+ * - DCE mode
+ * - no flow control
+ * - set RX ready oride
+ * - set TX ready oride
+ */
+ val = (AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S) |
+ AR933X_UART_CS_TX_RDY_ORIDE | AR933X_UART_CS_RX_RDY_ORIDE;
+ writel(val, regs + AR933X_UART_CS_REG);
+
+ ar933x_serial_get_scale_step(CONFIG_DEBUG_UART_CLOCK,
+ CONFIG_BAUDRATE, &scale, &step);
+
+ val = (scale & AR933X_UART_CLK_SCALE_M)
+ << AR933X_UART_CLK_SCALE_S;
+ val |= (step & AR933X_UART_CLK_STEP_M)
+ << AR933X_UART_CLK_STEP_S;
+ writel(val, regs + AR933X_UART_CLK_REG);
+}
+
+static inline void _debug_uart_putc(int c)
+{
+ void __iomem *regs;
+ u32 data;
+
+ regs = map_physmem(CONFIG_DEBUG_UART_BASE,
+ AR933X_UART_SIZE,
+ MAP_NOCACHE);
+
+ do {
+ data = readl(regs + AR933X_UART_DATA_REG);
+ } while (!(data & AR933X_UART_DATA_TX_CSR));
+
+ data = (u32)c | AR933X_UART_DATA_TX_CSR;
+ writel(data, regs + AR933X_UART_DATA_REG);
+}
+
+DEBUG_UART_FUNCS
+
+#endif
--
1.9.1