Re: [PATCH V1] mmc: core: Add partial initialization support

From: Ben Chuang
Date: Thu Jun 02 2022 - 03:57:19 EST


Hi Sarthak and others,

I like your patch, I'm not familiar with the whole sleep/wake flow.
But I have a question.

Regarding mmc_poweroff_notify() , there is a parameter notify_type.
In the spec., it has a value 0x04: SLEEP_NOTIFICATION (host is going
to put the device in sleep mode.)
Is there anything that needs to be changed in _mmc_suspend() before
calling mmc_sleepawake(host, true)/mmc_power_off(host)?
Thanks in advance.

Best regards,
Ben

On Wed, May 25, 2022 at 12:31 AM Kamasali Satyanarayan (Consultant)
(QUIC) <quic_kamasali@xxxxxxxxxxx> wrote:
>
> Hi,
>
> These patches will be further taken by Sarthak.
>
> Thanks,
> Satya
>
> -----Original Message-----
> From: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Sent: Wednesday, April 27, 2022 1:06 PM
> To: quic_spathi <quic_spathi@xxxxxxxxxxx>
> Cc: avri.altman@xxxxxxx; linus.walleij@xxxxxxxxxx; shawn.lin@xxxxxxxxxxxxxx; merez@xxxxxxxxxxxxxx; s.shtylyov@xxxxxx; huijin.park@xxxxxxxxxxx; briannorris@xxxxxxxxxxxx; digetx@xxxxxxxxx; linux-mmc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Veerabhadrarao Badiganti <vbadigan@xxxxxxxxxxxxxx>; Shaik Sajida Bhanu <sbhanu@xxxxxxxxxxxxxx>; Kamasali Satyanarayan (Consultant) (QUIC) <quic_kamasali@xxxxxxxxxxx>
> Subject: Re: [PATCH V1] mmc: core: Add partial initialization support
>
> On Tue, 26 Apr 2022 at 11:04, Srinivasarao Pathipati <quic_spathi@xxxxxxxxxxx> wrote:
> >
> > From: Maya Erez <merez@xxxxxxxxxxxxxx>
> >
> > This change adds the ability to partially initialize the MMC card by
> > using card Sleep/Awake sequence (CMD5).
> > Card will be sent to Sleep state during runtime/system suspend and
> > will be woken up during runtime/system resume.
> > By using this sequence the card doesn't need full initialization which
> > gives time reduction in system/runtime resume path.
> >
> > Signed-off-by: Maya Erez <merez@xxxxxxxxxxxxxx>
> > Signed-off-by: Veerabhadrarao Badiganti <vbadigan@xxxxxxxxxxxxxx>
> > Signed-off-by: Shaik Sajida Bhanu <sbhanu@xxxxxxxxxxxxxx>
> > Signed-off-by: kamasali <quic_kamasali@xxxxxxxxxxx>
> > Signed-off-by: Srinivasarao Pathipati <quic_spathi@xxxxxxxxxxx>
>
> It seems like this patch has been posted before [1]. Let me repeat my question sent back then.
>
> It would be nice if you could provide some more exact numbers of what the gain is for a couple of different eMMCs, to justify the change.
> Can you please do that?
>
> Kind regards
> Uffe
>
> [1]
> https://patchwork.kernel.org/project/linux-mmc/patch/1591277381-7734-1-git-send-email-vbadigan@xxxxxxxxxxxxxx/
>
> > ---
> > drivers/mmc/core/mmc.c | 149 ++++++++++++++++++++++++++++++++++++++++++++---
> > include/linux/mmc/card.h | 4 ++
> > include/linux/mmc/host.h | 2 +
> > 3 files changed, 146 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index
> > 9ab915b..8691c00 100644
> > --- a/drivers/mmc/core/mmc.c
> > +++ b/drivers/mmc/core/mmc.c
> > @@ -1942,7 +1942,14 @@ static int mmc_sleep_busy_cb(void *cb_data, bool *busy)
> > return 0;
> > }
> >
> > -static int mmc_sleep(struct mmc_host *host)
> > +static int mmc_can_sleepawake(struct mmc_host *host) {
> > + return host && (host->caps2 & MMC_CAP2_SLEEP_AWAKE) && host->card &&
> > + (host->card->ext_csd.rev >= 3);
> > +
> > +}
> > +
> > +static int mmc_sleepawake(struct mmc_host *host, bool sleep)
> > {
> > struct mmc_command cmd = {};
> > struct mmc_card *card = host->card; @@ -1953,14 +1960,17 @@
> > static int mmc_sleep(struct mmc_host *host)
> > /* Re-tuning can't be done once the card is deselected */
> > mmc_retune_hold(host);
> >
> > - err = mmc_deselect_cards(host);
> > - if (err)
> > - goto out_release;
> > + if (sleep) {
> > + err = mmc_deselect_cards(host);
> > + if (err)
> > + goto out_release;
> > + }
> >
> > cmd.opcode = MMC_SLEEP_AWAKE;
> > cmd.arg = card->rca << 16;
> > - cmd.arg |= 1 << 15;
> > use_r1b_resp = mmc_prepare_busy_cmd(host, &cmd, timeout_ms);
> > + if (sleep)
> > + cmd.arg |= 1 << 15;
> >
> > err = mmc_wait_for_cmd(host, &cmd, 0);
> > if (err)
> > @@ -1982,6 +1992,9 @@ static int mmc_sleep(struct mmc_host *host)
> >
> > err = __mmc_poll_for_busy(host, 0, timeout_ms,
> > &mmc_sleep_busy_cb, host);
> >
> > + if (!sleep)
> > + err = mmc_select_card(card);
> > +
> > out_release:
> > mmc_retune_release(host);
> > return err;
> > @@ -2080,6 +2093,66 @@ static int _mmc_flush_cache(struct mmc_host *host)
> > pr_err("%s: cache flush error %d\n",
> > mmc_hostname(host), err);
> > }
> > + return err;
> > +}
> > +
> > +static int mmc_cache_card_ext_csd(struct mmc_host *host) {
> > + int err;
> > + u8 *ext_csd;
> > + struct mmc_card *card = host->card;
> > +
> > + err = mmc_get_ext_csd(card, &ext_csd);
> > + if (err || !ext_csd) {
> > + pr_err("%s: %s: mmc_get_ext_csd failed (%d)\n",
> > + mmc_hostname(host), __func__, err);
> > + return err;
> > + }
> > + /* only cache read/write fields that the sw changes */
> > + card->ext_csd.raw_ext_csd_cmdq = ext_csd[EXT_CSD_CMDQ_MODE_EN];
> > + card->ext_csd.raw_ext_csd_cache_ctrl = ext_csd[EXT_CSD_CACHE_CTRL];
> > + card->ext_csd.raw_ext_csd_bus_width = ext_csd[EXT_CSD_BUS_WIDTH];
> > + card->ext_csd.raw_ext_csd_hs_timing =
> > + ext_csd[EXT_CSD_HS_TIMING];
> > +
> > + kfree(ext_csd);
> > +
> > + return 0;
> > +}
> > +
> > +static int mmc_test_awake_ext_csd(struct mmc_host *host) {
> > + int err;
> > + u8 *ext_csd;
> > + struct mmc_card *card = host->card;
> > +
> > + err = mmc_get_ext_csd(card, &ext_csd);
> > + if (err) {
> > + pr_err("%s: %s: mmc_get_ext_csd failed (%d)\n",
> > + mmc_hostname(host), __func__, err);
> > + return err;
> > + }
> > +
> > + /* only compare read/write fields that the sw changes */
> > + pr_debug("%s: %s: type(cached:current) cmdq(%d:%d) cache_ctrl(%d:%d) bus_width (%d:%d) timing(%d:%d)\n",
> > + mmc_hostname(host), __func__,
> > + card->ext_csd.raw_ext_csd_cmdq,
> > + ext_csd[EXT_CSD_CMDQ_MODE_EN],
> > + card->ext_csd.raw_ext_csd_cache_ctrl,
> > + ext_csd[EXT_CSD_CACHE_CTRL],
> > + card->ext_csd.raw_ext_csd_bus_width,
> > + ext_csd[EXT_CSD_BUS_WIDTH],
> > + card->ext_csd.raw_ext_csd_hs_timing,
> > + ext_csd[EXT_CSD_HS_TIMING]);
> > + err = !((card->ext_csd.raw_ext_csd_cmdq ==
> > + ext_csd[EXT_CSD_CMDQ_MODE_EN]) &&
> > + (card->ext_csd.raw_ext_csd_cache_ctrl ==
> > + ext_csd[EXT_CSD_CACHE_CTRL]) &&
> > + (card->ext_csd.raw_ext_csd_bus_width ==
> > + ext_csd[EXT_CSD_BUS_WIDTH]) &&
> > + (card->ext_csd.raw_ext_csd_hs_timing ==
> > + ext_csd[EXT_CSD_HS_TIMING]));
> > +
> > + kfree(ext_csd);
> >
> > return err;
> > }
> > @@ -2103,8 +2176,12 @@ static int _mmc_suspend(struct mmc_host *host, bool is_suspend)
> > ((host->caps2 & MMC_CAP2_FULL_PWR_CYCLE) || !is_suspend ||
> > (host->caps2 & MMC_CAP2_FULL_PWR_CYCLE_IN_SUSPEND)))
> > err = mmc_poweroff_notify(host->card, notify_type);
> > - else if (mmc_can_sleep(host->card))
> > - err = mmc_sleep(host);
> > + if (mmc_can_sleepawake(host)) {
> > + memcpy(&host->cached_ios, &host->ios, sizeof(host->cached_ios));
> > + mmc_cache_card_ext_csd(host);
> > + }
> > + if (mmc_can_sleep(host->card))
> > + err = mmc_sleepawake(host, true);
> > else if (!mmc_host_is_spi(host))
> > err = mmc_deselect_cards(host);
> >
> > @@ -2117,6 +2194,48 @@ static int _mmc_suspend(struct mmc_host *host, bool is_suspend)
> > return err;
> > }
> >
> > +static int mmc_partial_init(struct mmc_host *host) {
> > + int err = 0;
> > + struct mmc_card *card = host->card;
> > +
> > + mmc_set_bus_width(host, host->cached_ios.bus_width);
> > + mmc_set_timing(host, host->cached_ios.timing);
> > + if (host->cached_ios.enhanced_strobe) {
> > + host->ios.enhanced_strobe = true;
> > + if (host->ops->hs400_enhanced_strobe)
> > + host->ops->hs400_enhanced_strobe(host, &host->ios);
> > + }
> > + mmc_set_clock(host, host->cached_ios.clock);
> > + mmc_set_bus_mode(host, host->cached_ios.bus_mode);
> > +
> > + if (!mmc_card_hs400es(card) &&
> > + (mmc_card_hs200(card) || mmc_card_hs400(card))) {
> > + err = mmc_execute_tuning(card);
> > + if (err) {
> > + pr_err("%s: %s: Tuning failed (%d)\n",
> > + mmc_hostname(host), __func__, err);
> > + goto out;
> > + }
> > + }
> > + /*
> > + * The ext_csd is read to make sure the card did not went through
> > + * Power-failure during sleep period.
> > + * A subset of the W/E_P, W/C_P register will be tested. In case
> > + * these registers values are different from the values that were
> > + * cached during suspend, we will conclude that a Power-failure occurred
> > + * and will do full initialization sequence.
> > + */
> > + err = mmc_test_awake_ext_csd(host);
> > + if (err) {
> > + pr_debug("%s: %s: fail on ext_csd read (%d)\n",
> > + mmc_hostname(host), __func__, err);
> > + goto out;
> > + }
> > +out:
> > + return err;
> > +}
> > +
> > /*
> > * Suspend callback
> > */
> > @@ -2139,7 +2258,7 @@ static int mmc_suspend(struct mmc_host *host)
> > */
> > static int _mmc_resume(struct mmc_host *host) {
> > - int err = 0;
> > + int err = -EINVAL;
> >
> > mmc_claim_host(host);
> >
> > @@ -2147,7 +2266,19 @@ static int _mmc_resume(struct mmc_host *host)
> > goto out;
> >
> > mmc_power_up(host, host->card->ocr);
> > - err = mmc_init_card(host, host->card->ocr, host->card);
> > +
> > + if (mmc_can_sleepawake(host)) {
> > + err = mmc_sleepawake(host, false);
> > + if (!err)
> > + err = mmc_partial_init(host);
> > + else
> > + pr_err("%s: %s: awake failed (%d), fallback to full init\n",
> > + mmc_hostname(host), __func__, err);
> > + }
> > +
> > + if (err)
> > + err = mmc_init_card(host, host->card->ocr, host->card);
> > +
> > mmc_card_clr_suspended(host->card);
> >
> > out:
> > diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> > index 37f9758..ed7f6f7 100644
> > --- a/include/linux/mmc/card.h
> > +++ b/include/linux/mmc/card.h
> > @@ -86,6 +86,8 @@ struct mmc_ext_csd {
> > unsigned int data_tag_unit_size; /* DATA TAG UNIT size */
> > unsigned int boot_ro_lock; /* ro lock support */
> > bool boot_ro_lockable;
> > + u8 raw_ext_csd_cmdq; /* 15 */
> > + u8 raw_ext_csd_cache_ctrl; /* 33 */
> > bool ffu_capable; /* Firmware upgrade support */
> > bool cmdq_en; /* Command Queue enabled */
> > bool cmdq_support; /* Command Queue supported */
> > @@ -96,7 +98,9 @@ struct mmc_ext_csd {
> > u8 raw_partition_support; /* 160 */
> > u8 raw_rpmb_size_mult; /* 168 */
> > u8 raw_erased_mem_count; /* 181 */
> > + u8 raw_ext_csd_bus_width; /* 183 */
> > u8 strobe_support; /* 184 */
> > + u8 raw_ext_csd_hs_timing; /* 185 */
> > u8 raw_ext_csd_structure; /* 194 */
> > u8 raw_card_type; /* 196 */
> > u8 raw_driver_strength; /* 197 */
> > diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> > index c38072e..a9ddf7a 100644
> > --- a/include/linux/mmc/host.h
> > +++ b/include/linux/mmc/host.h
> > @@ -422,6 +422,7 @@ struct mmc_host {
> > #else
> > #define MMC_CAP2_CRYPTO 0
> > #endif
> > +#define MMC_CAP2_SLEEP_AWAKE (1 << 29) /* Use Sleep/Awake (CMD5) */
> > #define MMC_CAP2_ALT_GPT_TEGRA (1 << 28) /* Host with eMMC that has GPT entry at a non-standard location */
> >
> > int fixed_drv_type; /* fixed driver type for non-removable media */
> > @@ -441,6 +442,7 @@ struct mmc_host {
> > spinlock_t lock; /* lock for claim and bus ops */
> >
> > struct mmc_ios ios; /* current io bus settings */
> > + struct mmc_ios cached_ios;
> >
> > /* group bitfields together to minimize padding */
> > unsigned int use_spi_crc:1;
> > --
> > 2.7.4
> >