[U-Boot] [PATCH v8 6/9] drivers: serial: add serial driver for ar933x SOC

Simon Glass sjg at chromium.org
Sat Apr 9 20:34:30 CEST 2016


Hi Wills,

On 16 March 2016 at 02:59, Wills Wang <wills.wang at live.com> wrote:
> This patch add support for ar933x serial.
>
> Reviewed-by: Thomas Chou <thomas at wytron.com.tw>
> Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck at gmail.com>
> Reviewed-by: Simon Glass <sjg at chromium.org>
>
> Signed-off-by: Wills Wang <wills.wang at live.com>

Reviewed-by: Simon Glass <sjg at chromium.org>

But please see a comment below.

> ---
>
> Changes in v8:
> - Remove ath79_serial_write/read
> - Use pinctrl for serial
> - Add Kconfig dependence for serial option
>
> Changes in v7:
> - remove map_physmem for debug port
>
> 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
>
> Changes in v2:
> - Move serial driver code into drivers/serial
>
>  .../serial/qca,ar9330-uart.txt                     |  24 ++
>  drivers/serial/Kconfig                             |  18 ++
>  drivers/serial/Makefile                            |   1 +
>  drivers/serial/serial_ar933x.c                     | 255 +++++++++++++++++++++
>  4 files changed, 298 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 92d4212..d451441 100644
> --- a/drivers/serial/Kconfig
> +++ b/drivers/serial/Kconfig
> @@ -89,6 +89,15 @@ 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"
> +       depends on AR933X_UART
> +       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
> @@ -254,6 +263,15 @@ 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 && SOC_AR933X
> +       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 FSL_LPUART
>         bool "Freescale LPUART support"
>         help
> diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
> index 05bdf56..42e493a 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..d43f9c9
> --- /dev/null
> +++ b/drivers/serial/serial_ar933x.c
> @@ -0,0 +1,255 @@
> +/*
> + * Copyright (C) 2015-2016 Wills Wang <wills.wang at 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 <dm/pinctrl.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;
> +};
> +
> +/*
> + * 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)
> +{
> +       struct ar933x_serial_priv *priv = dev_get_priv(dev);
> +       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;
> +       writel(val, priv->regs + AR933X_UART_CLK_REG);
> +
> +       return 0;
> +}
> +
> +static int ar933x_serial_putc(struct udevice *dev, const char c)
> +{
> +       struct ar933x_serial_priv *priv = dev_get_priv(dev);
> +       u32 data;
> +
> +       data = readl(priv->regs + AR933X_UART_DATA_REG);
> +       if (!(data & AR933X_UART_DATA_TX_CSR))
> +               return -EAGAIN;
> +
> +       data  = (u32)c | AR933X_UART_DATA_TX_CSR;
> +       writel(data, priv->regs + AR933X_UART_DATA_REG);
> +
> +       return 0;
> +}
> +
> +static int ar933x_serial_getc(struct udevice *dev)
> +{
> +       struct ar933x_serial_priv *priv = dev_get_priv(dev);
> +       u32 data;
> +
> +       data = readl(priv->regs + AR933X_UART_DATA_REG);
> +       if (!(data & AR933X_UART_DATA_RX_CSR))
> +               return -EAGAIN;
> +
> +       writel(AR933X_UART_DATA_RX_CSR, priv->regs + AR933X_UART_DATA_REG);
> +       return data & AR933X_UART_DATA_TX_RX_MASK;
> +}
> +
> +static int ar933x_serial_pending(struct udevice *dev, bool input)
> +{
> +       struct ar933x_serial_priv *priv = dev_get_priv(dev);
> +       u32 data;
> +
> +       data = readl(priv->regs + 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 udevice *pinctrl;
> +       fdt_addr_t addr;
> +       u32 val;
> +       int ret;
> +
> +       ret = uclass_get_device(UCLASS_PINCTRL, 0, &pinctrl);
> +       if (ret)
> +               return ret;
> +       ret = pinctrl_get_periph_id(pinctrl, dev);
> +       if (ret < 0)
> +               return ret;
> +       ret = pinctrl_request(pinctrl, ret, 0);
> +       if (ret < 0)
> +               return ret;

().Can you check if you need this? It should be called automatically
by device_probe() which calls pinctrl_select_state().

> +
> +       addr = dev_get_addr(dev);
> +       if (addr == FDT_ADDR_T_NONE)
> +               return -EINVAL;
> +
> +       priv->regs = map_physmem(addr,
> +                                AR933X_UART_SIZE,
> +                                MAP_NOCACHE);

can you fill this out to 80cols?

> +
> +       /*
> +        * 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, priv->regs + 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 = (void *)CONFIG_DEBUG_UART_BASE;
> +       u32 val, scale, step;
> +
> +       /*
> +        * 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 = (void *)CONFIG_DEBUG_UART_BASE;
> +       u32 data;
> +
> +       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
>

Regards,
Simon


More information about the U-Boot mailing list