Re: [PATCH V16 08/23] mmc: core: Support UHS-II Auto Command Error Recovery
From: Victor Shih
Date: Fri May 31 2024 - 06:32:20 EST
On Fri, May 24, 2024 at 2:54 PM Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
>
> On 22/05/24 14:08, Victor Shih wrote:
> > From: Victor Shih <victor.shih@xxxxxxxxxxxxxxxxxxx>
> >
> > Add UHS-II Auto Command Error Recovery functionality
> > into the MMC request processing flow.
>
> Not sure what "auto" means here, but the commit message
> should outline what the spec. requires for error recovery.
>
Hi, Adrian
I will add instructions in the v17 version.
Thanks, Victor Shih
> >
> > Signed-off-by: Ben Chuang <ben.chuang@xxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Victor Shih <victor.shih@xxxxxxxxxxxxxxxxxxx>
> > ---
> >
> > Updates in V16:
> > - Separate the Error Recovery mechanism from patch#7 to patch#8.
> >
> > ---
> >
> > drivers/mmc/core/core.c | 4 ++
> > drivers/mmc/core/core.h | 1 +
> > drivers/mmc/core/sd_uhs2.c | 80 ++++++++++++++++++++++++++++++++++++++
> > include/linux/mmc/host.h | 6 +++
> > 4 files changed, 91 insertions(+)
> >
> > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> > index 68496c51a521..18642afc405f 100644
> > --- a/drivers/mmc/core/core.c
> > +++ b/drivers/mmc/core/core.c
> > @@ -403,6 +403,10 @@ void mmc_wait_for_req_done(struct mmc_host *host, struct mmc_request *mrq)
> > while (1) {
> > wait_for_completion(&mrq->completion);
> >
> > + if (host->ops->get_cd(host))
> > + if (mrq->cmd->error || (mrq->data && mrq->data->error))
> > + mmc_sd_uhs2_error_recovery(host, mrq);
>
> There are several issues with this:
>
> 1. It is not OK to start a request from within the request path
> because it is recursive:
>
> mmc_wait_for_req_done() <--
> mmc_sd_uhs2_error_recovery()
> sd_uhs2_abort_trans()
> mmc_wait_for_cmd()
> mmc_wait_for_req()
> mmc_wait_for_req_done() <--
>
> 2. The mmc block driver does not use this path
>
> 3. No need to always call ->get_cd() if there is no error
>
> It is worth considering whether the host controller could
> send the abort command as part of the original request, as
> is done with the stop command.
>
Hi, Adrian
1. It looks like just issuing a command in
mmc_wait_for_req_done() will cause a recursion.
I will drop sd_uhs2_abort_trans() and
sd_uhs2_abort_status_read() in the v17 version.
2. I have no idea about this part, could you please give me some advice?
3. I will try to modify this part in the v17 version.
Thanks, Victor Shih
> > +
> > cmd = mrq->cmd;
> >
> > if (!cmd->error || !cmd->retries ||
> > diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
> > index 920323faa834..259d47c8bb19 100644
> > --- a/drivers/mmc/core/core.h
> > +++ b/drivers/mmc/core/core.h
> > @@ -82,6 +82,7 @@ int mmc_attach_mmc(struct mmc_host *host);
> > int mmc_attach_sd(struct mmc_host *host);
> > int mmc_attach_sdio(struct mmc_host *host);
> > int mmc_attach_sd_uhs2(struct mmc_host *host);
> > +void mmc_sd_uhs2_error_recovery(struct mmc_host *mmc, struct mmc_request *mrq);
> >
> > /* Module parameters */
> > extern bool use_spi_crc;
> > diff --git a/drivers/mmc/core/sd_uhs2.c b/drivers/mmc/core/sd_uhs2.c
> > index 85939a2582dc..d5acb4e6ccac 100644
> > --- a/drivers/mmc/core/sd_uhs2.c
> > +++ b/drivers/mmc/core/sd_uhs2.c
> > @@ -1324,3 +1324,83 @@ int mmc_attach_sd_uhs2(struct mmc_host *host)
> >
> > return err;
> > }
> > +
> > +static void sd_uhs2_abort_trans(struct mmc_host *mmc)
> > +{
> > + struct mmc_request mrq = {};
> > + struct mmc_command cmd = {0};
> > + struct uhs2_command uhs2_cmd = {};
> > + int err;
> > +
> > + mrq.cmd = &cmd;
> > + mmc->ongoing_mrq = &mrq;
> > +
> > + uhs2_cmd.header = UHS2_NATIVE_PACKET | UHS2_PACKET_TYPE_CCMD |
> > + mmc->card->uhs2_config.node_id;
> > + uhs2_cmd.arg = ((UHS2_DEV_CMD_TRANS_ABORT & 0xFF) << 8) |
> > + UHS2_NATIVE_CMD_WRITE |
> > + (UHS2_DEV_CMD_TRANS_ABORT >> 8);
> > +
> > + sd_uhs2_cmd_assemble(&cmd, &uhs2_cmd, 0, 0);
> > + err = mmc_wait_for_cmd(mmc, &cmd, 0);
> > +
> > + if (err)
> > + pr_err("%s: %s: UHS2 CMD send fail, err= 0x%x!\n",
> > + mmc_hostname(mmc), __func__, err);
> > +}
> > +
> > +static void sd_uhs2_abort_status_read(struct mmc_host *mmc)
> > +{
> > + struct mmc_request mrq = {};
> > + struct mmc_command cmd = {0};
> > + struct uhs2_command uhs2_cmd = {};
> > + int err;
> > +
> > + mrq.cmd = &cmd;
> > + mmc->ongoing_mrq = &mrq;
> > +
> > + uhs2_cmd.header = UHS2_NATIVE_PACKET |
> > + UHS2_PACKET_TYPE_CCMD |
> > + mmc->card->uhs2_config.node_id;
> > + uhs2_cmd.arg = ((UHS2_DEV_STATUS_REG & 0xFF) << 8) |
> > + UHS2_NATIVE_CMD_READ |
> > + UHS2_NATIVE_CMD_PLEN_4B |
> > + (UHS2_DEV_STATUS_REG >> 8);
> > +
> > + sd_uhs2_cmd_assemble(&cmd, &uhs2_cmd, 0, 0);
> > + err = mmc_wait_for_cmd(mmc, &cmd, 0);
> > +
> > + if (err)
> > + pr_err("%s: %s: UHS2 CMD send fail, err= 0x%x!\n",
> > + mmc_hostname(mmc), __func__, err);
> > +}
> > +
> > +void mmc_sd_uhs2_error_recovery(struct mmc_host *mmc, struct mmc_request *mrq)
> > +{
> > + mmc->ops->uhs2_reset_cmd_data(mmc);
>
> The host controller should already have done any resets needed.
> sdhci already has support for doing that - see host->pending_reset
>
Hi, Adrian
I'm not sure what this means. Could you please give me more information?
Thanks, Victor Shih
> > +
> > + if (mrq->data) {
> > + if (mrq->data->error && mmc_card_uhs2(mmc)) {
> > + if (mrq->cmd) {
> > + switch (mrq->cmd->error) {
> > + case ETIMEDOUT:
> > + case EILSEQ:
> > + case EIO:
> > + sd_uhs2_abort_trans(mmc);
> > + sd_uhs2_abort_status_read(mmc);
>
> What is the purpose of sd_uhs2_abort_status_read() here?
> It is not obvious it does anything.
>
Hi, Adrian
sd_uhs2_abort_status_read() seems to only have read status,
I will drop this in the v17 version.
Thanks, Victor Shih
> > + break;
> > + default:
> > + break;
> > + }
> > + }
> > + }
> > + } else {
> > + if (mrq->cmd) {
> > + switch (mrq->cmd->error) {
> > + case ETIMEDOUT:
> > + sd_uhs2_abort_trans(mmc);
> > + break;
> > + }
> > + }
> > + }
> > +}
> > diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> > index fc9520b3bfa4..c914a58f7e1e 100644
> > --- a/include/linux/mmc/host.h
> > +++ b/include/linux/mmc/host.h
> > @@ -271,6 +271,12 @@ struct mmc_host_ops {
> > * negative errno in case of a failure or zero for success.
> > */
> > int (*uhs2_control)(struct mmc_host *host, enum sd_uhs2_operation op);
> > +
> > + /*
> > + * The uhs2_reset_cmd_data callback is used to excute reset
> > + * when a auto command error occurs.
> > + */
> > + void (*uhs2_reset_cmd_data)(struct mmc_host *host);
> > };
> >
> > struct mmc_cqe_ops {
>