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Message-ID: <CAPDyKFo7H=fOiX49gttrKO3gwe=ddYMjdgrO_xSnnZjZh7P7ZA@mail.gmail.com>
Date: Wed, 27 Apr 2022 09:35:47 +0200
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Srinivasarao Pathipati <quic_spathi@...cinc.com>
Cc: avri.altman@....com, linus.walleij@...aro.org,
shawn.lin@...k-chips.com, merez@...eaurora.org, s.shtylyov@....ru,
huijin.park@...sung.com, briannorris@...omium.org,
digetx@...il.com, linux-mmc@...r.kernel.org,
linux-kernel@...r.kernel.org,
Veerabhadrarao Badiganti <vbadigan@...eaurora.org>,
Shaik Sajida Bhanu <sbhanu@...eaurora.org>,
kamasali <quic_kamasali@...cinc.com>
Subject: Re: [PATCH V1] mmc: core: Add partial initialization support
On Tue, 26 Apr 2022 at 11:04, Srinivasarao Pathipati
<quic_spathi@...cinc.com> wrote:
>
> From: Maya Erez <merez@...eaurora.org>
>
> 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@...eaurora.org>
> Signed-off-by: Veerabhadrarao Badiganti <vbadigan@...eaurora.org>
> Signed-off-by: Shaik Sajida Bhanu <sbhanu@...eaurora.org>
> Signed-off-by: kamasali <quic_kamasali@...cinc.com>
> Signed-off-by: Srinivasarao Pathipati <quic_spathi@...cinc.com>
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@codeaurora.org/
> ---
> 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
>
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