[U-Boot] [PATCH 3/4 V2] S5P: Serial: Add fdt support to driver

[Simon Glass]

Hi Rajeshwari,

On Fri, Mar 1, 2013 at 2:16 AM, Rajeshwari Shinde
<rajeshwari.s at samsung.com> wrote:
> This patch adds FDT support to the serial s5p driver.
> At present disabling the serial console (from the device tree) crashes
> U-Boot. Add checks for this case, so that execution can continue without
> a serial console.
> It also enables the serial_s5p driver recognize the silent_console option.
>
> Signed-off-by: Abhilash Kesavan <a.kesavan at samsung.com>
> Signed-off-by: Gabe Black <gabeblack at google.com>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> Signed-off-by: Rajeshwari Shinde <rajeshwari.s at samsung.com>
> Acked-by: Simon Glass <sjg at chromium.org>
> ---
> Changes in V2:
>         - None
>  drivers/serial/serial_s5p.c |   80 +++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 80 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/serial/serial_s5p.c b/drivers/serial/serial_s5p.c
> index 3c41242..4502ffb 100644
> --- a/drivers/serial/serial_s5p.c
> +++ b/drivers/serial/serial_s5p.c
> @@ -24,16 +24,30 @@
>  #include <common.h>
>  #include <linux/compiler.h>
>  #include <asm/io.h>
> +#include <fdtdec.h>
>  #include <asm/arch/uart.h>
>  #include <asm/arch/clk.h>
>  #include <serial.h>
>
>  DECLARE_GLOBAL_DATA_PTR;
>
> +/* Information about a serial port */
> +struct fdt_serial {
> +       u32 base_addr;  /* address of registers in physical memory */
> +       u8 port_id;     /* uart port number */
> +       u8 enabled;     /* 1 if enabled, 0 if disabled */
> +} config = {
> +       -1U

I think it might be better to explicitly put this on the end of the variable:

__attribute__ ((section(".data")))

to force it into the data section. I think that is the only reason for
the -1 assignment.

> +};
> +
>  static inline struct s5p_uart *s5p_get_base_uart(int dev_index)
>  {
> +#ifdef CONFIG_OF_CONTROL
> +       return (struct s5p_uart *)(config.base_addr);
> +#else
>         u32 offset = dev_index * sizeof(struct s5p_uart);
>         return (struct s5p_uart *)(samsung_get_base_uart() + offset);
> +#endif
>  }
>
>  /*
> @@ -69,6 +83,9 @@ void serial_setbrg_dev(const int dev_index)
>         u32 baudrate = gd->baudrate;
>         u32 val;
>
> +       if (!config.enabled)
> +               return;
> +
>         val = uclk / baudrate;
>
>         writel(val / 16 - 1, &uart->ubrdiv);
> @@ -87,6 +104,16 @@ int serial_init_dev(const int dev_index)
>  {
>         struct s5p_uart *const uart = s5p_get_base_uart(dev_index);
>
> +#if defined(CONFIG_SILENT_CONSOLE) && \
> +               defined(CONFIG_OF_CONTROL) && \
> +               !defined(CONFIG_SPL_BUILD)
> +       if (fdtdec_get_config_int(gd->fdt_blob, "silent_console", 0))
> +               gd->flags |= GD_FLG_SILENT;
> +#endif
> +
> +       if (!config.enabled)
> +               return 0;
> +
>         /* reset and enable FIFOs, set triggers to the maximum */
>         writel(0, &uart->ufcon);
>         writel(0, &uart->umcon);
> @@ -129,6 +156,9 @@ int serial_getc_dev(const int dev_index)
>  {
>         struct s5p_uart *const uart = s5p_get_base_uart(dev_index);
>
> +       if (!config.enabled)
> +               return 0;
> +
>         /* wait for character to arrive */
>         while (!(readl(&uart->utrstat) & 0x1)) {
>                 if (serial_err_check(dev_index, 0))
> @@ -145,6 +175,9 @@ void serial_putc_dev(const char c, const int dev_index)
>  {
>         struct s5p_uart *const uart = s5p_get_base_uart(dev_index);
>
> +       if (!config.enabled)
> +               return;
> +
>         /* wait for room in the tx FIFO */
>         while (!(readl(&uart->utrstat) & 0x2)) {
>                 if (serial_err_check(dev_index, 1))
> @@ -165,6 +198,9 @@ int serial_tstc_dev(const int dev_index)
>  {
>         struct s5p_uart *const uart = s5p_get_base_uart(dev_index);
>
> +       if (!config.enabled)
> +               return 0;
> +
>         return (int)(readl(&uart->utrstat) & 0x1);
>  }
>
> @@ -207,8 +243,51 @@ DECLARE_S5P_SERIAL_FUNCTIONS(3);
>  struct serial_device s5p_serial3_device =
>         INIT_S5P_SERIAL_STRUCTURE(3, "s5pser3");
>
> +#ifdef CONFIG_OF_CONTROL
> +int fdtdec_decode_console(int *index, struct fdt_serial *uart)
> +{
> +       const void *blob = gd->fdt_blob;
> +       int node;
> +
> +       node = fdtdec_next_alias(blob, "serial", COMPAT_SAMSUNG_EXYNOS5_SERIAL,
> +               index);
> +       if (node < 0)
> +               return node;
> +
> +       uart->base_addr = fdtdec_get_addr(blob, node, "reg");
> +       if (uart->base_addr == FDT_ADDR_T_NONE)
> +               return -FDT_ERR_NOTFOUND;
> +
> +       uart->port_id = fdtdec_get_int(blob, node, "id", -1);
> +       uart->enabled = fdtdec_get_is_enabled(blob, node);
> +
> +       return 0;
> +}
> +#endif
> +
>  __weak struct serial_device *default_serial_console(void)
>  {
> +#ifdef CONFIG_OF_CONTROL
> +       int index = 0;

blank line here

> +       if (fdtdec_decode_console(&index, &config)) {
> +               debug("Cannot decode default console node\n");
> +               return NULL;
> +       }

I think this function might be called for every character output prior
to relocation. So perhaps you need to only do the decode once? You can
check for base_addr being 0 perhaps and only init if it is 0.

> +
> +       if (config.port_id == 0)
> +               return &s5p_serial0_device;
> +       else if (config.port_id == 1)
> +               return &s5p_serial1_device;
> +       else if (config.port_id == 2)
> +               return &s5p_serial2_device;
> +       else if (config.port_id == 3)
> +               return &s5p_serial3_device;
> +       else
> +               debug("Unknown config.port_id: %d", config.port_id);
> +
> +       return NULL;
> +#else
> +       config.enabled = 1;
>  #if defined(CONFIG_SERIAL0)
>         return &s5p_serial0_device;
>  #elif defined(CONFIG_SERIAL1)
> @@ -220,6 +299,7 @@ __weak struct serial_device *default_serial_console(void)
>  #else
>  #error "CONFIG_SERIAL? missing."
>  #endif
> +#endif
>  }
>
>  void s5p_serial_initialize(void)
> --
> 1.7.4.4
>

Regards,
Simon