mmc: core: Add wp_grp_size sysfs node

The eMMC card can be set into write-protected mode to prevent data from
being accidentally modified or deleted. Wp_grp_size (Write Protect Group
Size) refers to an attribute of the eMMC card, used to manage write
protection and is the CSD register [36:32] of the eMMC device. Wp_grp_size
(Write Protect Group Size) indicates how many eMMC blocks are contained in
each write protection group on the eMMC card.

To allow userspace easy access of the CSD register bits, let's add sysfs
node "wp_grp_size".

Signed-off-by: Lin Gui <lin.gui@mediatek.com>
Signed-off-by: Bo Ye <bo.ye@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20231218230532.82427-1-bo.ye@mediatek.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 7b996db570c9275facc2d79ff95996c4f61cd164..adf7b70cf1b660523a35b05f5b22bfadea9a1c64 100644 (file)
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -136,6 +136,17 @@ static void mmc_set_erase_size(struct mmc_card *card)
        mmc_init_erase(card);
 }
 
+
+static void mmc_set_wp_grp_size(struct mmc_card *card)
+{
+       if (card->ext_csd.erase_group_def & 1)
+               card->wp_grp_size = card->ext_csd.hc_erase_size *
+                       card->ext_csd.raw_hc_erase_gap_size;
+       else
+               card->wp_grp_size = card->csd.erase_size *
+                       (card->csd.wp_grp_size + 1);
+}
+
 /*
  * Given a 128-bit response, decode to our card CSD structure.
  */
@@ -186,6 +197,7 @@ static int mmc_decode_csd(struct mmc_card *card)
                b = UNSTUFF_BITS(resp, 37, 5);
                csd->erase_size = (a + 1) * (b + 1);
                csd->erase_size <<= csd->write_blkbits - 9;
+               csd->wp_grp_size = UNSTUFF_BITS(resp, 32, 5);
        }
 
        return 0;
@@ -785,6 +797,7 @@ MMC_DEV_ATTR(csd, "%08x%08x%08x%08x\n", card->raw_csd[0], card->raw_csd[1],
 MMC_DEV_ATTR(date, "%02d/%04d\n", card->cid.month, card->cid.year);
 MMC_DEV_ATTR(erase_size, "%u\n", card->erase_size << 9);
 MMC_DEV_ATTR(preferred_erase_size, "%u\n", card->pref_erase << 9);
+MMC_DEV_ATTR(wp_grp_size, "%u\n", card->wp_grp_size << 9);
 MMC_DEV_ATTR(ffu_capable, "%d\n", card->ext_csd.ffu_capable);
 MMC_DEV_ATTR(hwrev, "0x%x\n", card->cid.hwrev);
 MMC_DEV_ATTR(manfid, "0x%06x\n", card->cid.manfid);
@@ -845,6 +858,7 @@ static struct attribute *mmc_std_attrs[] = {
        &dev_attr_date.attr,
        &dev_attr_erase_size.attr,
        &dev_attr_preferred_erase_size.attr,
+       &dev_attr_wp_grp_size.attr,
        &dev_attr_fwrev.attr,
        &dev_attr_ffu_capable.attr,
        &dev_attr_hwrev.attr,
@@ -1759,7 +1773,7 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
                        mmc_set_erase_size(card);
                }
        }
-
+       mmc_set_wp_grp_size(card);
        /*
         * Ensure eMMC user default partition is enabled
         */

diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 47eeb122524c4469de68220889fcc398ac64abfd..f34407cc27888d8bccf550eea7645e3671ef89c2 100644 (file)
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -32,6 +32,7 @@ struct mmc_csd {
        unsigned int            r2w_factor;
        unsigned int            max_dtr;
        unsigned int            erase_size;             /* In sectors */
+       unsigned int            wp_grp_size;
        unsigned int            read_blkbits;
        unsigned int            write_blkbits;
        unsigned int            capacity;
@@ -303,6 +304,7 @@ struct mmc_card {
        unsigned int            eg_boundary;    /* don't cross erase-group boundaries */
        unsigned int            erase_arg;      /* erase / trim / discard */
        u8                      erased_byte;    /* value of erased bytes */
+       unsigned int            wp_grp_size;    /* write group size in sectors */
 
        u32                     raw_cid[4];     /* raw card CID */
        u32                     raw_csd[4];     /* raw card CSD */