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From:   Avri Altman <Avri.Altman@wdc.com>
To:     Srinivasarao Pathipati <quic_spathi@quicinc.com>,
        "ulf.hansson@linaro.org" <ulf.hansson@linaro.org>,
        "linus.walleij@linaro.org" <linus.walleij@linaro.org>,
        "shawn.lin@rock-chips.com" <shawn.lin@rock-chips.com>,
        "merez@codeaurora.org" <merez@codeaurora.org>,
        "s.shtylyov@omp.ru" <s.shtylyov@omp.ru>,
        "huijin.park@samsung.com" <huijin.park@samsung.com>,
        "briannorris@chromium.org" <briannorris@chromium.org>,
        "digetx@gmail.com" <digetx@gmail.com>,
        "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     Veerabhadrarao Badiganti <vbadigan@codeaurora.org>,
        Shaik Sajida Bhanu <sbhanu@codeaurora.org>,
        kamasali <quic_kamasali@quicinc.com>
Subject: RE: [PATCH V1] mmc: core: Add partial initialization support
Thread-Topic: [PATCH V1] mmc: core: Add partial initialization support
Thread-Index: AQHYWUyoCuEqwcrJJUG+ipv40mEWZq0CDgxg
Date:   Tue, 26 Apr 2022 18:33:38 +0000
Message-ID: <DM6PR04MB6575541A6720A96997653A6CFCFB9@DM6PR04MB6575.namprd04.prod.outlook.com>
References: <1650963852-4173-1-git-send-email-quic_spathi@quicinc.com>
In-Reply-To: <1650963852-4173-1-git-send-email-quic_spathi@quicinc.com>
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> From: Maya Erez <merez@codeaurora.org>
>=20
> 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.
>=20
> Signed-off-by: Maya Erez <merez@codeaurora.org>
> Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
> Signed-off-by: Shaik Sajida Bhanu <sbhanu@codeaurora.org>
> Signed-off-by: kamasali <quic_kamasali@quicinc.com>
> Signed-off-by: Srinivasarao Pathipati <quic_spathi@quicinc.com>
> ---
>  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(-)
>=20
> 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;
>  }
>=20
> -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 >=3D 3);
Maybe just:
return mmc_can_sleep(host->card) && (host->caps2 & MMC_CAP2_SLEEP_AWAKE);

> +
> +}
> +
> +static int mmc_sleepawake(struct mmc_host *host, bool sleep)
>  {
>         struct mmc_command cmd =3D {};
>         struct mmc_card *card =3D 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);
>=20
> -       err =3D mmc_deselect_cards(host);
> -       if (err)
> -               goto out_release;
> +       if (sleep) {
> +               err =3D mmc_deselect_cards(host);
> +               if (err)
> +                       goto out_release;
> +       }
>=20
>         cmd.opcode =3D MMC_SLEEP_AWAKE;
>         cmd.arg =3D card->rca << 16;
> -       cmd.arg |=3D 1 << 15;
>         use_r1b_resp =3D mmc_prepare_busy_cmd(host, &cmd, timeout_ms);
> +       if (sleep)
> +               cmd.arg |=3D 1 << 15;
>=20
>         err =3D mmc_wait_for_cmd(host, &cmd, 0);
>         if (err)
> @@ -1982,6 +1992,9 @@ static int mmc_sleep(struct mmc_host *host)
>=20
>         err =3D __mmc_poll_for_busy(host, 0, timeout_ms, &mmc_sleep_busy_=
cb,
> host);
>=20
> +       if (!sleep)
> +               err =3D 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 =3D host->card;
> +
> +       err =3D 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 =3D ext_csd[EXT_CSD_CMDQ_MODE_EN];
> +       card->ext_csd.raw_ext_csd_cache_ctrl =3D ext_csd[EXT_CSD_CACHE_CT=
RL];
> +       card->ext_csd.raw_ext_csd_bus_width =3D ext_csd[EXT_CSD_BUS_WIDTH=
];
> +       card->ext_csd.raw_ext_csd_hs_timing =3D 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 =3D host->card;
> +
> +       err =3D 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 =3D !((card->ext_csd.raw_ext_csd_cmdq =3D=3D
> +                       ext_csd[EXT_CSD_CMDQ_MODE_EN]) &&
> +               (card->ext_csd.raw_ext_csd_cache_ctrl =3D=3D
> +                       ext_csd[EXT_CSD_CACHE_CTRL]) &&
> +               (card->ext_csd.raw_ext_csd_bus_width =3D=3D
> +                       ext_csd[EXT_CSD_BUS_WIDTH]) &&
> +               (card->ext_csd.raw_ext_csd_hs_timing =3D=3D
> +                       ext_csd[EXT_CSD_HS_TIMING]));
> +
> +       kfree(ext_csd);
>=20
>         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 =3D mmc_poweroff_notify(host->card, notify_type);
> -       else if (mmc_can_sleep(host->card))
> -               err =3D 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 =3D mmc_sleepawake(host, true);
>         else if (!mmc_host_is_spi(host))
>                 err =3D mmc_deselect_cards(host);
>=20
> @@ -2117,6 +2194,48 @@ static int _mmc_suspend(struct mmc_host *host,
> bool is_suspend)
>         return err;
>  }
>=20
> +static int mmc_partial_init(struct mmc_host *host)
> +{
> +       int err =3D 0;
> +       struct mmc_card *card =3D 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 =3D 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 =3D 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 o=
ccurred
> +        * and will do full initialization sequence.
> +        */
This seems like a strange enough hack.
Power-failure during sleep period? really?

> +       err =3D 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;
Redundant goto

> +       }
> +out:
> +       return err;
> +}

Thanks,
Avri

> +
>  /*
>   * Suspend callback
>   */
> @@ -2139,7 +2258,7 @@ static int mmc_suspend(struct mmc_host *host)
>   */
>  static int _mmc_resume(struct mmc_host *host)
>  {
> -       int err =3D 0;
> +       int err =3D -EINVAL;
>=20
>         mmc_claim_host(host);
>=20
> @@ -2147,7 +2266,19 @@ static int _mmc_resume(struct mmc_host *host)
>                 goto out;
>=20
>         mmc_power_up(host, host->card->ocr);
> -       err =3D mmc_init_card(host, host->card->ocr, host->card);
> +
> +       if (mmc_can_sleepawake(host)) {
> +               err =3D mmc_sleepawake(host, false);
> +               if (!err)
> +                       err =3D mmc_partial_init(host);
> +               else
> +                       pr_err("%s: %s: awake failed (%d), fallback to fu=
ll init\n",
> +                               mmc_hostname(host), __func__, err);
> +       }
> +
> +       if (err)
> +               err =3D mmc_init_card(host, host->card->ocr, host->card);
> +
>         mmc_card_clr_suspended(host->card);
>=20
>  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 suppor=
t */
>         bool                    boot_ro_lockable;
> +       u8                      raw_ext_csd_cmdq;       /* 15 */
> +       u8                      raw_ext_csd_cache_ctrl; /* 33 */
>         bool                    ffu_capable;    /* Firmware upgrade suppo=
rt */
>         bool                    cmdq_en;        /* Command Queue enabled =
*/
>         bool                    cmdq_support;   /* Command Queue supporte=
d */
> @@ -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 */
>=20
>         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 */
>=20
>         struct mmc_ios          ios;            /* current io bus setting=
s */
> +       struct mmc_ios          cached_ios;
>=20
>         /* group bitfields together to minimize padding */
>         unsigned int            use_spi_crc:1;
> --
> 2.7.4