Re: [U-Boot] [PATCH 13/69] x86: Allow use of serial soon after relocation

Hi Simon,

On Mon, Mar 7, 2016 at 10:27 AM, Simon Glass sjg@chromium.org wrote:

At present on x86 machines with use cache-as-RAM, the memory goes away just before board_init_r() is called. This means that serial drivers are no-longer unavailable, until initr_dm() it called, etc.

Any attempt to use printf() within this period will cause a hang.

To fix this, mark the serial devices as 'unavailable' when it is no-longer available. Bring it back when serial_initialize() is called. This means that the debug UART will be used instead for this period.

Signed-off-by: Simon Glass sjg@chromium.org

common/board_f.c | 7 +++++++ drivers/serial/serial-uclass.c | 1 + 2 files changed, 8 insertions(+)

diff --git a/common/board_f.c b/common/board_f.c index 622093a..109025a 100644 --- a/common/board_f.c +++ b/common/board_f.c @@ -1096,6 +1096,13 @@ void board_init_f_r(void) hang();

    /*

•    * The pre-relocation drivers may be using memory that has now gone
  

•    * away. Mark serial as unavailable - this will fall back to the debug
  

•    * UART if available.
  

•    */
  

•   gd->flags &= ~GD_FLG_SERIAL_READY;
  

What about other architectures (non-X86 and non-ARC)?

•   /*
     * U-Boot has been copied into SDRAM, the BSS has been cleared etc.
     * Transfer execution from Flash to RAM by calculating the address
     * of the in-RAM copy of board_init_r() and calling it
  

diff --git a/drivers/serial/serial-uclass.c b/drivers/serial/serial-uclass.c index 1c447ff..6562be0 100644 --- a/drivers/serial/serial-uclass.c +++ b/drivers/serial/serial-uclass.c @@ -116,6 +116,7 @@ int serial_init(void) void serial_initialize(void) { serial_find_console_or_panic();

•   gd->flags |= GD_FLG_SERIAL_READY;
  

I think we can simply replace this to:

void serial_initialize(void) { serial_init(); }

Regards, Bin