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

Daniel Schwierzeck
2015-12-26T13:20:28Z

Am 25.12.2015 um 19:56 schrieb Wills Wang:
> 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>

use the existing and generic implementation in include/div64.h

> +#include <asm/types.h>
> +#include <asm/arch/ar71xx_regs.h>

#include <mach/ar71xx_regs.h>

I wonder how you can stil compile your code

> +
> +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;
> +};

if you always support device-tree, you do not need platform data

> +
> +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');

remove this, the serial core driver takes care of it

> +
> + do {
> + data = ar933x_serial_read(dev, AR933X_UART_DATA_REG);
> + } while (!(data & AR933X_UART_DATA_TX_CSR));

remove this, the serial core driver takes care of it via your pending
callback (ar933x_serial_pending)

> +
> + 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));

dito

> +
> + 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);

move this code to function ar933x_serial_probe and drop this function

> + 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),

drop the two lines, you do not need to allocate platdata

> + .priv_auto_alloc_size = sizeof(struct ar933x_serial_priv),
> + .probe = ar933x_serial_probe,
> + .ops = &ar933x_serial_ops,
> + .flags = DM_FLAG_PRE_RELOC,
> +};
>

--
- Daniel