On Mon, 2018-04-09 at 15:24 +1000, Nicholas Piggin wrote:
> Convert to using the standard delay poll/delay form.
>
> The console code:
>
> - Did not previously delay or sleep in its busy loop.
>
> Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
> Signed-off-by: Nicholas Piggin <npig...@gmail.com>
Does it help with anything ? We don't technically *have* to delay or
wait, I thought it would be good to try to hit the console as fast as
possible in that case...
Ben.
> ---
> arch/powerpc/platforms/powernv/opal.c | 38 ++++++++++++++++-----------
> 1 file changed, 23 insertions(+), 15 deletions(-)
>
> diff --git a/arch/powerpc/platforms/powernv/opal.c
> b/arch/powerpc/platforms/powernv/opal.c
> index 87d4c0aa7f64..473c8ce14a34 100644
> --- a/arch/powerpc/platforms/powernv/opal.c
> +++ b/arch/powerpc/platforms/powernv/opal.c
> @@ -378,33 +378,41 @@ int opal_put_chars(uint32_t vtermno, const char *data,
> int total_len)
> /* We still try to handle partial completions, though they
> * should no longer happen.
> */
> - rc = OPAL_BUSY;
> - while(total_len > 0 && (rc == OPAL_BUSY ||
> - rc == OPAL_BUSY_EVENT || rc == OPAL_SUCCESS)) {
> +
> + while (total_len > 0) {
> olen = cpu_to_be64(total_len);
> - rc = opal_console_write(vtermno, &olen, data);
> +
> + rc = OPAL_BUSY;
> + while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
> + rc = opal_console_write(vtermno, &olen, data);
> + if (rc == OPAL_BUSY_EVENT) {
> + mdelay(OPAL_BUSY_DELAY_MS);
> + opal_poll_events(NULL);
> + } else if (rc == OPAL_BUSY) {
> + mdelay(OPAL_BUSY_DELAY_MS);
> + }
> + }
> +
> len = be64_to_cpu(olen);
>
> /* Closed or other error drop */
> - if (rc != OPAL_SUCCESS && rc != OPAL_BUSY &&
> - rc != OPAL_BUSY_EVENT) {
> - written += total_len;
> + if (rc != OPAL_SUCCESS) {
> + written += total_len; /* drop remaining chars */
> break;
> }
> - if (rc == OPAL_SUCCESS) {
> - total_len -= len;
> - data += len;
> - written += len;
> - }
> +
> + total_len -= len;
> + data += len;
> + written += len;
> +
> /* This is a bit nasty but we need that for the console to
> * flush when there aren't any interrupts. We will clean
> * things a bit later to limit that to synchronous path
> * such as the kernel console and xmon/udbg
> */
> - do
> + do {
> opal_poll_events(&evt);
> - while(rc == OPAL_SUCCESS &&
> - (be64_to_cpu(evt) & OPAL_EVENT_CONSOLE_OUTPUT));
> + } while (be64_to_cpu(evt) & OPAL_EVENT_CONSOLE_OUTPUT);
> }
> spin_unlock_irqrestore(&opal_write_lock, flags);
> return written;
