Hi,
I tested this on the foundation model and it hangs.
-Geoff
On Thu, 2015-05-14 at 11:25 +0530, Pratyush Anand wrote:
> Previous transmission must be completed before next character to be
> transmitted, otherwise TX buffer may saturate and we will not see all
> the characters on screen.
>
> Signed-off-by: Pratyush Anand <panand at redhat.com>
> ---
> purgatory/arch/arm64/purgatory-arm64.c | 24 +++++++++++++++++++++++-
> 1 file changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/purgatory/arch/arm64/purgatory-arm64.c
> b/purgatory/arch/arm64/purgatory-arm64.c
> index 25960c30bd05..3a1c9243bfa2 100644
> --- a/purgatory/arch/arm64/purgatory-arm64.c
> +++ b/purgatory/arch/arm64/purgatory-arm64.c
> @@ -11,15 +11,37 @@ extern uint32_t *arm64_sink;
> extern void (*arm64_kernel_entry)(uint64_t);
> extern uint64_t arm64_dtb_addr;
>
> +static void wait_for_xmit_complete(void)
> +{
> + volatile uint32_t status;
> + volatile uint32_t *status_reg;
> +
> + /*
> + * Since most of the UART with ARM platform has LSR register
> at
> + * offset 0x14 and should have value as 0x60 for TX empty,
> so we
> + * have hardcoded these values. Can modify in future if need
> + * arises.
> + */
> + status_reg = (volatile uint32_t *)((uint64_t)arm64_sink +
> 0x14);
> + while (1) {
> + status = *status_reg;
> + if ((status & 0x60) == 0x60)
> + break;
> + }
> +}
> +
> void putchar(int ch)
> {
> if (!arm64_sink)
> return;
>
> + wait_for_xmit_complete();
> *arm64_sink = ch;
>
> - if (ch == '\n')
> + if (ch == '\n') {
> + wait_for_xmit_complete();
> *arm64_sink = '\r';
> + }
> }
>
> void setup_arch(void)
