linux-kernel - RE: [PATCH 1/2] mmc: core: update life time and pre eol info values on sysfs read

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Date:   Thu, 10 Mar 2022 14:07:34 +0000
From:   Avri Altman <Avri.Altman@....com>
To:     Marc Mattmueller <marc.mattmueller@...module.com>,
        "ulf.hansson@...aro.org" <ulf.hansson@...aro.org>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 1/2] mmc: core: update life time and pre eol info values
 on sysfs read

 
> The mmc estimated life time values and pre-eol info values were only read at
> start-up and were not updated on sysfs read.
> Thus, added update of the ext_csd structure on sysfs read of
> device_life_time_est_typ_a, device_life_time_est_typ_b and pre_eol_info.
I agree that a snapshot on init doesn't make much sense.
But you can read it using mmc-utils, why not just remove the useless entries?

Thanks,
Avri

> 
> Signed-off-by: Marc Mattmueller <marc.mattmueller@...module.com>
> ---
>  drivers/mmc/core/mmc.c | 87
> ++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 83 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index
> 43d1b9b2fa49..d9537c894e33 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -357,6 +357,25 @@ static void mmc_manage_gp_partitions(struct
> mmc_card *card, u8 *ext_csd)
>  /* Minimum partition switch timeout in milliseconds */
>  #define MMC_MIN_PART_SWITCH_TIME       300
> 
> +/*
> + * Update extended CSD parameters changing during runtime.
> + */
> +static int mmc_update_ext_csd_runtime_params(struct mmc_card *card,
> u8
> +*ext_csd) {
> +       int err = 0;
> +
> +       /* eMMC v5 or later */
> +       if (card->ext_csd.rev >= 7) {
> +               card->ext_csd.pre_eol_info = ext_csd[EXT_CSD_PRE_EOL_INFO];
> +               card->ext_csd.device_life_time_est_typ_a =
> +                       ext_csd[EXT_CSD_DEVICE_LIFE_TIME_EST_TYP_A];
> +               card->ext_csd.device_life_time_est_typ_b =
> +                       ext_csd[EXT_CSD_DEVICE_LIFE_TIME_EST_TYP_B];
> +       }
> +
> +       return err;
> +}
> +
>  /*
>   * Decode extended CSD.
>   */
> @@ -367,6 +386,16 @@ static int mmc_decode_ext_csd(struct mmc_card
> *card, u8 *ext_csd)
>         struct device_node *np;
>         bool broken_hpi = false;
> 
> +       /*
> +        * After once having initialized the ext_csd structure, we want to
> +        * update only the changing parts. To check this the revistion is
> +        * taken.
> +        */
> +       if (card->ext_csd.rev != 0) {
> +               err = mmc_update_ext_csd_runtime_params(card, ext_csd);
> +               goto out;
> +       }
> +
>         /* Version is coded in the CSD_STRUCTURE byte in the EXT_CSD register
> */
>         card->ext_csd.raw_ext_csd_structure = ext_csd[EXT_CSD_STRUCTURE];
>         if (card->csd.structure == 3) {
> @@ -791,10 +820,6 @@ MMC_DEV_ATTR(name, "%s\n", card-
> >cid.prod_name);  MMC_DEV_ATTR(oemid, "0x%04x\n", card->cid.oemid);
> MMC_DEV_ATTR(prv, "0x%x\n", card->cid.prv);  MMC_DEV_ATTR(rev,
> "0x%x\n", card->ext_csd.rev); -MMC_DEV_ATTR(pre_eol_info, "0x%02x\n",
> card->ext_csd.pre_eol_info); -MMC_DEV_ATTR(life_time, "0x%02x
> 0x%02x\n",
> -       card->ext_csd.device_life_time_est_typ_a,
> -       card->ext_csd.device_life_time_est_typ_b);
>  MMC_DEV_ATTR(serial, "0x%08x\n", card->cid.serial);
> MMC_DEV_ATTR(enhanced_area_offset, "%llu\n",
>                 card->ext_csd.enhanced_area_offset);
> @@ -807,6 +832,60 @@ MMC_DEV_ATTR(ocr, "0x%08x\n", card->ocr);
> MMC_DEV_ATTR(rca, "0x%04x\n", card->rca);  MMC_DEV_ATTR(cmdq_en,
> "%d\n", card->ext_csd.cmdq_en);
> 
> +static int mmc_update_csd(struct mmc_card *card) {
> +       int err = 0;
> +
> +       mmc_claim_host(card->host);
> +       err = mmc_read_ext_csd(card);
> +       mmc_release_host(card->host);
> +       return err;
> +}
> +
> +static ssize_t life_time_show(struct device *dev,
> +                             struct device_attribute *attr,
> +                             char *buf) {
> +       int err = 0;
> +       struct mmc_card *card = mmc_dev_to_card(dev);
> +
> +       /* before eMMC v5 */
> +       if (card->ext_csd.rev < 7)
> +               return sprintf(buf, "%s\n", "-");
> +
> +       /* eMMC v5 or later */
> +       err = mmc_update_csd(card);
> +       if (err)
> +               return (ssize_t)err;
> +
> +       return sprintf(buf, "0x%02x 0x%02x\n",
> +                               card->ext_csd.device_life_time_est_typ_a,
> +
> +card->ext_csd.device_life_time_est_typ_b);
> +}
> +
> +static DEVICE_ATTR_RO(life_time);
> +
> +static ssize_t pre_eol_info_show(struct device *dev,
> +                                struct device_attribute *attr,
> +                                char *buf) {
> +       int err = 0;
> +       struct mmc_card *card = mmc_dev_to_card(dev);
> +
> +       /* before eMMC v5 */
> +       if (card->ext_csd.rev < 7)
> +               return sprintf(buf, "%s\n", "-");
> +
> +       /* eMMC v5 or later */
> +       err = mmc_update_csd(card);
> +       if (err)
> +               return (ssize_t)err;
> +
> +       return sprintf(buf, "0x%02x\n", card->ext_csd.pre_eol_info); }
> +
> +static DEVICE_ATTR_RO(pre_eol_info);
> +
>  static ssize_t mmc_fwrev_show(struct device *dev,
>                               struct device_attribute *attr,
>                               char *buf)
> --
> 2.20.1