On Wed, 3 Jan 2024 at 12:29, Jorge Ramirez-Ortiz <jorge@xxxxxxxxxxxx> wrote:
>
> Requesting a retune before switching to the RPMB partition has been
> observed to cause CRC errors on the RPMB reads (-EILSEQ).
>
> Since RPMB reads can not be retried, the clients would be directly
> affected by the errors.
>
> This commit disables the retune request prior to switching to the RPMB
> partition: mmc_retune_pause() no longer triggers a retune before the
> pause period begins.
>
> This was verified with the sdhci-of-arasan driver (ZynqMP) configured
> for HS200 using two separate eMMC cards (DG4064 and 064GB2). In both
> cases, the error was easy to reproduce triggering every few tenths of
> reads.
>
> With this commit, systems that were utilizing OP-TEE to access RPMB
> variables will experience an enhanced performance. Specifically, when
> OP-TEE is configured to employ RPMB as a secure storage solution, it not
> only writes the data but also the secure filesystem within the
> partition. As a result, retrieving any variable involves multiple RPMB
> reads, typically around five.
>
> For context, on ZynqMP, each retune request consumed approximately
> 8ms. Consequently, reading any RPMB variable used to take at the very
> minimum 40ms.
>
> After droping the need to retune before switching to the RPMB partition,
> this is no longer the case.
>
> Signed-off-by: Jorge Ramirez-Ortiz <jorge@xxxxxxxxxxxx>
> Acked-by: Avri Altman <avri.altman@xxxxxxx>
> Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Thanks for updating the commit message, very nice! And thanks Adrian
for reviewing this!
Applied for next, thanks!
Kind regards
Uffe
> ---
> v3:
> Added some performance information to the commit message
> v2:
> mmc_retune_pause() no longer can trigger a retune.
> Keeping Avri Altman Acked-by since they are functionally equivalent.
> v1:
> modify mmc_retune_pause to optionally trigger a retune.
>
>
> drivers/mmc/core/host.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> index 096093f7be00..ed44920e92df 100644
> --- a/drivers/mmc/core/host.c
> +++ b/drivers/mmc/core/host.c
> @@ -119,13 +119,12 @@ void mmc_retune_enable(struct mmc_host *host)
>
> /*
> * Pause re-tuning for a small set of operations. The pause begins after the
> - * next command and after first doing re-tuning.
> + * next command.
> */
> void mmc_retune_pause(struct mmc_host *host)
> {
> if (!host->retune_paused) {
> host->retune_paused = 1;
> - mmc_retune_needed(host);
> mmc_retune_hold(host);
> }
> }
> --
> 2.34.1
