[U-Boot] [PATCH v4 4/8] mips: ath79: add serial driver for ar933x SOC

Wills Wang
2015-12-25T18:56:24Z

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

Changes in v4: None
Changes in v3: None
Changes in v2: None

drivers/serial/Makefile | 1 +
drivers/serial/serial_ar933x.c | 225 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 226 insertions(+)
create mode 100644 drivers/serial/serial_ar933x.c

diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index dd87147..9a7ad89 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-$(CONFIG_AR933X_SERIAL) += serial_ar933x.o
obj-$(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..efca93c
--- /dev/null
+++ b/drivers/serial/serial_ar933x.c
@@ -0,0 +1,225 @@
+/*
+ * (C) Copyright 2015
+ * Wills Wang, <wills.wang@live.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <serial.h>
+#include <asm/io.h>
+#include <asm/addrspace.h>
+#include <asm/div64.h>
+#include <asm/types.h>
+#include <asm/arch/ar71xx_regs.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#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_platdata {
+ void __iomem *regs;
+};
+
+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;
+
+ if (c == '\n')
+ ar933x_serial_putc(dev, '\r');
+
+ do {
+ data = ar933x_serial_read(dev, AR933X_UART_DATA_REG);
+ } while (!(data & AR933X_UART_DATA_TX_CSR));
+
+ 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;
+
+ do {
+ data = ar933x_serial_read(dev, AR933X_UART_DATA_REG);
+ } while (!(data & AR933X_UART_DATA_RX_CSR));
+
+ 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);
+ struct ar933x_serial_platdata *plat = dev_get_platdata(dev);
+ u32 val;
+
+ priv->regs = plat->regs;
+
+ /*
+ * 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 int ar933x_serial_ofdata_to_platdata(struct udevice *dev)
+{
+ struct ar933x_serial_platdata *plat = dev_get_platdata(dev);
+ fdt_addr_t addr;
+
+ addr = dev_get_addr(dev);
+ if (addr == FDT_ADDR_T_NONE)
+ return -EINVAL;
+
+ plat->regs = map_physmem(addr,
+ AR933X_UART_SIZE,
+ MAP_NOCACHE);
+ 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 = "ath79,ar933x-uart" },
+ { }
+};
+
+U_BOOT_DRIVER(serial_ar933x) = {
+ .name = "serial_ar933x",
+ .id = UCLASS_SERIAL,
+ .of_match = ar933x_serial_ids,
+ .ofdata_to_platdata = ar933x_serial_ofdata_to_platdata,
+ .platdata_auto_alloc_size = sizeof(struct ar933x_serial_platdata),
+ .priv_auto_alloc_size = sizeof(struct ar933x_serial_priv),
+ .probe = ar933x_serial_probe,
+ .ops = &ar933x_serial_ops,
+ .flags = DM_FLAG_PRE_RELOC,
+};
--
1.9.1