Hi,
On 26 July 2016 at 04:55, Tien Fong Chee <tfc...@altera.com> wrote:
> This patch would do checking on device tree to ensure the UART exist
> in the system and ready for console before setting have_console to true.
> This is required to avoid unexpected behavior such as hang during UART
> initialization.
>
> Signed-off-by: Tien Fong Chee <tfc...@altera.com>
> Cc: Dinh Nguyen <dingu...@opensource.altera.com>
> Cc: Dinh Nguyen <dinh.li...@gmail.com>
> Cc: ChinLiang <cl...@altera.com>
> Cc: Thomas Chou <tho...@wytron.com.tw>
> Cc: Simon Glass <s...@chromium.org>
> Cc: Marek Vasut <ma...@denx.de>
> ---
> common/console.c | 11 ++++---
> common/spl/spl.c | 3 +-
> drivers/serial/serial.c | 58 +++++++++++++++++++++++++++++++++++-
> include/asm-generic/global_data.h | 1 +
> include/serial.h | 1 +
> 5 files changed, 66 insertions(+), 8 deletions(-)
Another way to deal with this would be to have the driver return
-EBUSY (or perhaps -EAGAIN) and set this flag in
serial_find_console_or_panic(). After all, the unavailability of
serial is a driver-specific thing, right?
How / when does the FPGA get programmed on your system?
>
> diff --git a/common/console.c b/common/console.c
> index 12293f3..c37486c 100644
> --- a/common/console.c
> +++ b/common/console.c
> @@ -690,14 +690,15 @@ int console_assign(int file, const char *devname)
> /* Called before relocation - use serial functions */
> int console_init_f(void)
> {
> - gd->have_console = 1;
> -
> + if(gd->uart_ready_for_console) {
> + gd->have_console = 1;
> #ifdef CONFIG_SILENT_CONSOLE
> - if (getenv("silent") != NULL)
> - gd->flags |= GD_FLG_SILENT;
> + if (getenv("silent") != NULL)
> + gd->flags |= GD_FLG_SILENT;
> #endif
>
> - print_pre_console_buffer(PRE_CONSOLE_FLUSHPOINT1_SERIAL);
> + print_pre_console_buffer(PRE_CONSOLE_FLUSHPOINT1_SERIAL);
> + }
>
> return 0;
> }
> diff --git a/common/spl/spl.c b/common/spl/spl.c
> index b7ec333..c18827d 100644
> --- a/common/spl/spl.c
> +++ b/common/spl/spl.c
> @@ -488,7 +488,8 @@ void preloader_console_init(void)
>
> serial_init(); /* serial communications setup */
>
> - gd->have_console = 1;
> + if(gd->uart_ready_for_console)
> + gd->have_console = 1;
>
> puts("\nU-Boot SPL " PLAIN_VERSION " (" U_BOOT_DATE " - " \
> U_BOOT_TIME ")\n");
> diff --git a/drivers/serial/serial.c b/drivers/serial/serial.c
> index f1bd15b..95690e0 100644
> --- a/drivers/serial/serial.c
> +++ b/drivers/serial/serial.c
> @@ -35,6 +35,51 @@ static void serial_null(void)
> }
>
> /**
> + * uart_console_null() - This empty function would be used if UART console
> checking
> + * function is not compiled into U-boot.
> + *
> + * This routine returns true to indicate UART is ready for console by
> default.
> + * The driver is aliased to this empty function in case
> + * the driver is not compiled into U-Boot.
> + */
> +static int uart_console_null(void)
> +{
> + return 1;
> +}
> +
> +/**
> + * uart_console_func() - Forward declare of driver checking UART is ready
> based
> + * on device tree.
> + * @name: Name of driver which checking UART is ready based on device
> tree .
> + *
> + * This macro expands onto forward declaration of a driver checking
> + * UART is ready based on device tree, which allows own assigned function
> name.
> + * The declaration is made weak and aliases to uart_console_null() so in case
> + * the driver is not compiled in, the function is still declared and can
> + * be used, but aliases to uart_console_null() and thus is optimized away.
> + */
> +#define uart_console_func(name) \
> + int name(const void *blob)
> \
> + __attribute__((weak, alias("uart_console_null")));
> +
> +uart_console_func(is_default_uart_console_true);
> +
> +/**
> + * is_uart_console_true() - Common function to abstract the specific UART
> + * console checking function.
> + *
> + * This is common interface for specific UART console checking function.
> + */
> +int is_uart_console_true(const void *blob)
> +{
> + int ret = 0;
> +
> + ret |= is_default_uart_console_true(blob);
> +
> + return ret;
> +}
> +
> +/**
> * on_baudrate() - Update the actual baudrate when the env var changes
> *
> * This will check for a valid baudrate and only apply it if valid.
> @@ -415,8 +460,17 @@ static struct serial_device *get_current(void)
> */
> int serial_init(void)
> {
> - gd->flags |= GD_FLG_SERIAL_READY;
> - return get_current()->start();
> + if(is_uart_console_true(gd->fdt_blob))
> + gd->uart_ready_for_console = 1;
> + else
> + gd->uart_ready_for_console = 0;
> +
> + if(gd->uart_ready_for_console) {
> + gd->flags |= GD_FLG_SERIAL_READY;
> + return get_current()->start();
> + }
> +
> + return 0;
> }
>
> /**
> diff --git a/include/asm-generic/global_data.h
> b/include/asm-generic/global_data.h
> index a6d1d2a..1cb7ef7 100644
> --- a/include/asm-generic/global_data.h
> +++ b/include/asm-generic/global_data.h
> @@ -44,6 +44,7 @@ typedef struct global_data {
> #ifdef CONFIG_BOARD_TYPES
> unsigned long board_type;
> #endif
> + unsigned long uart_ready_for_console; /* UART ready to support
> console */
> unsigned long have_console; /* serial_init() was called */
> #ifdef CONFIG_PRE_CONSOLE_BUFFER
> unsigned long precon_buf_idx; /* Pre-Console buffer index */
> diff --git a/include/serial.h b/include/serial.h
> index 47332c5..a95bf70 100644
> --- a/include/serial.h
> +++ b/include/serial.h
> @@ -50,6 +50,7 @@ extern void serial_initialize(void);
> extern void serial_stdio_init(void);
> extern int serial_assign(const char *name);
> extern void serial_reinit_all(void);
> +extern int is_uart_console_true(const void *blob);
>
> /* For usbtty */
> #ifdef CONFIG_USB_TTY
> --
> 1.7.7.4
>
Regards,
Simon
_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
http://lists.denx.de/mailman/listinfo/u-boot
