[PATCH 1/2] mmc: add helper to query max enhanced part size

[Matthias Schiffer]

From: Markus Niebel <markus.nie...@ew.tq-group.com>

This helper will be used later on in an extension of the mmc
command.

Signed-off-by: Markus Niebel <markus.nie...@ew.tq-group.com>
Signed-off-by: Matthias Schiffer <matthias.schif...@ew.tq-group.com>
---
 drivers/mmc/mmc.c | 38 ++++++++++++++++++++++++++++++++++++++
 include/mmc.h     |  1 +
 2 files changed, 39 insertions(+)

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index d3babbfeb1c..c1b1ef7eb0b 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -1039,6 +1039,44 @@ int mmc_switch_part(struct mmc *mmc, unsigned int 
part_num)
 }
 
 #if CONFIG_IS_ENABLED(MMC_HW_PARTITIONING)
+int mmc_max_enhanced_size_sectors(struct mmc *mmc, u64 *size)
+{
+       u64 sz;
+       int err;
+
+       ALLOC_CACHE_ALIGN_BUFFER(u8, ext_csd, MMC_MAX_BLOCK_LEN);
+
+       if (IS_SD(mmc) || mmc->version < MMC_VERSION_4_41) {
+               pr_err("eMMC >= 4.4 required for enhanced user data area\n");
+               return -EMEDIUMTYPE;
+       }
+
+       if (!(mmc->part_support & PART_SUPPORT)) {
+               pr_err("Card does not support partitioning\n");
+               return -EMEDIUMTYPE;
+       }
+
+       if (!mmc->hc_wp_grp_size) {
+               pr_err("Card does not define HC WP group size\n");
+               return -EMEDIUMTYPE;
+       }
+
+       err = mmc_send_ext_csd(mmc, ext_csd);
+       if (err)
+               return err;
+
+       sz =
+               (ext_csd[EXT_CSD_MAX_ENH_SIZE_MULT + 2] << 16) +
+               (ext_csd[EXT_CSD_MAX_ENH_SIZE_MULT + 1] << 8) +
+               ext_csd[EXT_CSD_MAX_ENH_SIZE_MULT];
+       sz *= ext_csd[EXT_CSD_HC_ERASE_GRP_SIZE];
+       sz *= ext_csd[EXT_CSD_HC_WP_GRP_SIZE];
+       sz *= SZ_1K;
+       *size = sz;
+
+       return 0;
+}
+
 int mmc_hwpart_config(struct mmc *mmc,
                      const struct mmc_hwpart_conf *conf,
                      enum mmc_hwpart_conf_mode mode)
diff --git a/include/mmc.h b/include/mmc.h
index b92e2553402..3e1fc82d9b4 100644
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -846,6 +846,7 @@ void print_mmc_devices(char separator);
  */
 int get_mmc_num(void);
 int mmc_switch_part(struct mmc *mmc, unsigned int part_num);
+int mmc_max_enhanced_size_sectors(struct mmc *mmc, u64 *size);
 int mmc_hwpart_config(struct mmc *mmc, const struct mmc_hwpart_conf *conf,
                      enum mmc_hwpart_conf_mode mode);
 
-- 
2.17.1