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 tfchee@altera.com Cc: Dinh Nguyen dinguyen@opensource.altera.com Cc: Dinh Nguyen dinh.linux@gmail.com Cc: ChinLiang clsee@altera.com Cc: Thomas Chou thomas@wytron.com.tw Cc: Simon Glass sjg@chromium.org Cc: Marek Vasut marex@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(-)
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