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

Wills Wang
2015-12-27T06:28:35Z

On 12/26/2015 09:20 PM, Daniel Schwierzeck wrote:
>
> 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)
>

Serial core driver don't query and wait the pending function before
"serial_getc" and "serial_putc", so these statements can't remove,
or board don't work.
>> +
>> + 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
ditto
>
>> +
>> + 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,
>> +};
>>