mmc: core: Fix select power class after resume

Use the saved values in card->ext_csd when selecting power class.
By doing this the power class will be selected even if mmc_init_card
is called with oldcard != NULL, which is the case after a suspend/resume.

Today ext_csd is NULL if mmc_init_card is called with oldcard != NULL
and power class will not be selected.

According to the eMMC specification the POWER_CLASS value is reset after
power failure, H/W reset assertion and any CMD0 reset.

Signed-off-by: Fredrik Soderstedt <fredrik.soderstedt@stericsson.com>
Reviewed-by: Johan Rudholm <jrudholm@gmail.com>
Acked By: Girish K S <girish.shivananjappa@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

2 files changed, 59 insertions, 25 deletions

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index dd6810eebd3f..3a69b947130b 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -461,6 +461,24 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
                  */
                 card->ext_csd.boot_ro_lock = ext_csd[EXT_CSD_BOOT_WP];
                 card->ext_csd.boot_ro_lockable = true;
+
+                /* Save power class values */
+                card->ext_csd.raw_pwr_cl_52_195 =
+                        ext_csd[EXT_CSD_PWR_CL_52_195];
+                card->ext_csd.raw_pwr_cl_26_195 =
+                        ext_csd[EXT_CSD_PWR_CL_26_195];
+                card->ext_csd.raw_pwr_cl_52_360 =
+                        ext_csd[EXT_CSD_PWR_CL_52_360];
+                card->ext_csd.raw_pwr_cl_26_360 =
+                        ext_csd[EXT_CSD_PWR_CL_26_360];
+                card->ext_csd.raw_pwr_cl_200_195 =
+                        ext_csd[EXT_CSD_PWR_CL_200_195];
+                card->ext_csd.raw_pwr_cl_200_360 =
+                        ext_csd[EXT_CSD_PWR_CL_200_360];
+                card->ext_csd.raw_pwr_cl_ddr_52_195 =
+                        ext_csd[EXT_CSD_PWR_CL_DDR_52_195];
+                card->ext_csd.raw_pwr_cl_ddr_52_360 =
+                        ext_csd[EXT_CSD_PWR_CL_DDR_52_360];
         }
 
         if (card->ext_csd.rev >= 5) {
@@ -607,7 +625,23 @@ static int mmc_compare_ext_csds(struct mmc_card *card, unsigned bus_width)
                 (card->ext_csd.raw_sectors[2] ==
                         bw_ext_csd[EXT_CSD_SEC_CNT + 2]) &&
                 (card->ext_csd.raw_sectors[3] ==
-                        bw_ext_csd[EXT_CSD_SEC_CNT + 3]));
+                        bw_ext_csd[EXT_CSD_SEC_CNT + 3]) &&
+                (card->ext_csd.raw_pwr_cl_52_195 ==
+                        bw_ext_csd[EXT_CSD_PWR_CL_52_195]) &&
+                (card->ext_csd.raw_pwr_cl_26_195 ==
+                        bw_ext_csd[EXT_CSD_PWR_CL_26_195]) &&
+                (card->ext_csd.raw_pwr_cl_52_360 ==
+                        bw_ext_csd[EXT_CSD_PWR_CL_52_360]) &&
+                (card->ext_csd.raw_pwr_cl_26_360 ==
+                        bw_ext_csd[EXT_CSD_PWR_CL_26_360]) &&
+                (card->ext_csd.raw_pwr_cl_200_195 ==
+                        bw_ext_csd[EXT_CSD_PWR_CL_200_195]) &&
+                (card->ext_csd.raw_pwr_cl_200_360 ==
+                        bw_ext_csd[EXT_CSD_PWR_CL_200_360]) &&
+                (card->ext_csd.raw_pwr_cl_ddr_52_195 ==
+                        bw_ext_csd[EXT_CSD_PWR_CL_DDR_52_195]) &&
+                (card->ext_csd.raw_pwr_cl_ddr_52_360 ==
+                        bw_ext_csd[EXT_CSD_PWR_CL_DDR_52_360]));
         if (err)
                 err = -EINVAL;
 
@@ -676,11 +710,10 @@ static struct device_type mmc_type = {
  * mmc_switch command.
  */
 static int mmc_select_powerclass(struct mmc_card *card,
-                unsigned int bus_width, u8 *ext_csd)
+                unsigned int bus_width)
 {
         int err = 0;
-        unsigned int pwrclass_val;
-        unsigned int index = 0;
+        unsigned int pwrclass_val = 0;
         struct mmc_host *host;
 
         BUG_ON(!card);
@@ -688,9 +721,6 @@ static int mmc_select_powerclass(struct mmc_card *card,
         host = card->host;
         BUG_ON(!host);
 
-        if (ext_csd == NULL)
-                return 0;
-
         /* Power class selection is supported for versions >= 4.0 */
         if (card->csd.mmca_vsn < CSD_SPEC_VER_4)
                 return 0;
@@ -702,13 +732,13 @@ static int mmc_select_powerclass(struct mmc_card *card,
         switch (1 << host->ios.vdd) {
         case MMC_VDD_165_195:
                 if (host->ios.clock <= 26000000)
-                        index = EXT_CSD_PWR_CL_26_195;
+                        pwrclass_val = card->ext_csd.raw_pwr_cl_26_195;
                 else if (host->ios.clock <= 52000000)
-                        index = (bus_width <= EXT_CSD_BUS_WIDTH_8) ?
-                                EXT_CSD_PWR_CL_52_195 :
-                                EXT_CSD_PWR_CL_DDR_52_195;
+                        pwrclass_val = (bus_width <= EXT_CSD_BUS_WIDTH_8) ?
+                                card->ext_csd.raw_pwr_cl_52_195 :
+                                card->ext_csd.raw_pwr_cl_ddr_52_195;
                 else if (host->ios.clock <= 200000000)
-                        index = EXT_CSD_PWR_CL_200_195;
+                        pwrclass_val = card->ext_csd.raw_pwr_cl_200_195;
                 break;
         case MMC_VDD_27_28:
         case MMC_VDD_28_29:
@@ -720,13 +750,13 @@ static int mmc_select_powerclass(struct mmc_card *card,
         case MMC_VDD_34_35:
         case MMC_VDD_35_36:
                 if (host->ios.clock <= 26000000)
-                        index = EXT_CSD_PWR_CL_26_360;
+                        pwrclass_val = card->ext_csd.raw_pwr_cl_26_360;
                 else if (host->ios.clock <= 52000000)
-                        index = (bus_width <= EXT_CSD_BUS_WIDTH_8) ?
-                                EXT_CSD_PWR_CL_52_360 :
-                                EXT_CSD_PWR_CL_DDR_52_360;
+                        pwrclass_val = (bus_width <= EXT_CSD_BUS_WIDTH_8) ?
+                                card->ext_csd.raw_pwr_cl_52_360 :
+                                card->ext_csd.raw_pwr_cl_ddr_52_360;
                 else if (host->ios.clock <= 200000000)
-                        index = EXT_CSD_PWR_CL_200_360;
+                        pwrclass_val = card->ext_csd.raw_pwr_cl_200_360;
                 break;
         default:
                 pr_warning("%s: Voltage range not supported "
@@ -734,8 +764,6 @@ static int mmc_select_powerclass(struct mmc_card *card,
                 return -EINVAL;
         }
 
-        pwrclass_val = ext_csd[index];
-
         if (bus_width & (EXT_CSD_BUS_WIDTH_8 | EXT_CSD_DDR_BUS_WIDTH_8))
                 pwrclass_val = (pwrclass_val & EXT_CSD_PWR_CL_8BIT_MASK) >>
                                 EXT_CSD_PWR_CL_8BIT_SHIFT;
@@ -1131,7 +1159,7 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 
                 ext_csd_bits = (bus_width == MMC_BUS_WIDTH_8) ?
                                 EXT_CSD_BUS_WIDTH_8 : EXT_CSD_BUS_WIDTH_4;
-                err = mmc_select_powerclass(card, ext_csd_bits, ext_csd);
+                err = mmc_select_powerclass(card, ext_csd_bits);
                 if (err)
                         pr_warning("%s: power class selection to bus width %d"
                                    " failed\n", mmc_hostname(card->host),
@@ -1164,8 +1192,7 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
                         bus_width = bus_widths[idx];
                         if (bus_width == MMC_BUS_WIDTH_1)
                                 ddr = 0; /* no DDR for 1-bit width */
-                        err = mmc_select_powerclass(card, ext_csd_bits[idx][0],
-                                                    ext_csd);
+                        err = mmc_select_powerclass(card, ext_csd_bits[idx][0]);
                         if (err)
                                 pr_warning("%s: power class selection to "
                                            "bus width %d failed\n",
@@ -1195,8 +1222,7 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
                 }
 
                 if (!err && ddr) {
-                        err = mmc_select_powerclass(card, ext_csd_bits[idx][1],
-                                                    ext_csd);
+                        err = mmc_select_powerclass(card, ext_csd_bits[idx][1]);
                         if (err)
                                 pr_warning("%s: power class selection to "
                                            "bus width %d ddr %d failed\n",
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index f31725ba49f3..6a98f32670b8 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -94,7 +94,11 @@ struct mmc_ext_csd {
         u8                      raw_ext_csd_structure;  /* 194 */
         u8                      raw_card_type;          /* 196 */
         u8                      out_of_int_time;        /* 198 */
-        u8                      raw_s_a_timeout;                /* 217 */
+        u8                      raw_pwr_cl_52_195;      /* 200 */
+        u8                      raw_pwr_cl_26_195;      /* 201 */
+        u8                      raw_pwr_cl_52_360;      /* 202 */
+        u8                      raw_pwr_cl_26_360;      /* 203 */
+        u8                      raw_s_a_timeout;        /* 217 */
         u8                      raw_hc_erase_gap_size;  /* 221 */
         u8                      raw_erase_timeout_mult; /* 223 */
         u8                      raw_hc_erase_grp_size;  /* 224 */
@@ -102,6 +106,10 @@ struct mmc_ext_csd {
         u8                      raw_sec_erase_mult;     /* 230 */
         u8                      raw_sec_feature_support;/* 231 */
         u8                      raw_trim_mult;          /* 232 */
+        u8                      raw_pwr_cl_200_195;     /* 236 */
+        u8                      raw_pwr_cl_200_360;     /* 237 */
+        u8                      raw_pwr_cl_ddr_52_195;  /* 238 */
+        u8                      raw_pwr_cl_ddr_52_360;  /* 239 */
         u8                      raw_bkops_status;       /* 246 */
         u8                      raw_sectors[4];         /* 212 - 4 bytes */