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

Daniel Schwierzeck
2015-12-26T17:19:17Z

Am 26.12.2015 um 17:54 schrieb Wills Wang:
>
>
> 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
> Ok.
>>> +#include <asm/types.h>
>>> +#include <asm/arch/ar71xx_regs.h>
>> #include <mach/ar71xx_regs.h>
>>
>> I wonder how you can stil compile your code
> U-boot create symbolic links from arch/mips/mach-ath79/include/mach
> to arch/mips/include/asm/arch.

but it should not. Only if you enable CREATE_ARCH_SYMLINK. Maybe this is
some magic for backward compatibility. Anyway the long-term goal is to
remove the creation of symbolic links and to use "#include <mach/file.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;
>>> +};
>> if you always support device-tree, you do not need platform data
> Ok.
>>> +
>>> +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
> Ok.
>>> +
>>> + 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)
> Ok.
>>> +
>>> + 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
> Ok.
>>> +
>>> + 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
> Ok.
>>> + 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
>>
> Ok.
>>> + .priv_auto_alloc_size = sizeof(struct ar933x_serial_priv),
>>> + .probe = ar933x_serial_probe,
>>> + .ops = &ar933x_serial_ops,
>>> + .flags = DM_FLAG_PRE_RELOC,
>>> +};
>>>
>

--
- Daniel