mmc: refactor SD startup to make it easier to support new modes

The SDcard startup process currently handles only 2 modes. To make it
easier to add support for more modes, let's make the process more generic
and use a list of the modes to try.
The major functional change is that when a mode fails we try the next one.
Not all modes are tried, only those supported by the card and the host.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index deb4786585ac1ac80adf759b2942ba8760b679de..3002b727c83412bde3402808293696ce53250797 100644 (file)
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -237,7 +237,8 @@ int mmc_send_status(struct mmc *mmc, int timeout)
                            (cmd.response[0] & MMC_STATUS_CURR_STATE) !=
                             MMC_STATE_PRG)
                                break;
-                       else if (cmd.response[0] & MMC_STATUS_MASK) {
+
+                       if (cmd.response[0] & MMC_STATUS_MASK) {
 #if !defined(CONFIG_SPL_BUILD) || defined(CONFIG_SPL_LIBCOMMON_SUPPORT)
                                printf("Status Error: 0x%08X\n",
                                        cmd.response[0]);
@@ -610,7 +611,7 @@ static int mmc_change_freq(struct mmc *mmc)
        char cardtype;
        int err;
 
-       mmc->card_caps = 0;
+       mmc->card_caps = MMC_MODE_1BIT;
 
        if (mmc_host_is_spi(mmc))
                return 0;
@@ -936,7 +937,7 @@ static int sd_switch(struct mmc *mmc, int mode, int group, u8 value, u8 *resp)
 }
 
 
-static int sd_change_freq(struct mmc *mmc)
+static int sd_get_capabilities(struct mmc *mmc)
 {
        int err;
        struct mmc_cmd cmd;
@@ -945,7 +946,7 @@ static int sd_change_freq(struct mmc *mmc)
        struct mmc_data data;
        int timeout;
 
-       mmc->card_caps = 0;
+       mmc->card_caps = MMC_MODE_1BIT;
 
        if (mmc_host_is_spi(mmc))
                return 0;
@@ -1022,26 +1023,53 @@ retry_scr:
        }
 
        /* If high-speed isn't supported, we return */
-       if (!(__be32_to_cpu(switch_status[3]) & SD_HIGHSPEED_SUPPORTED))
-               return 0;
+       if (__be32_to_cpu(switch_status[3]) & SD_HIGHSPEED_SUPPORTED)
+               mmc->card_caps |= MMC_CAP(SD_HS);
 
-       /*
-        * If the host doesn't support SD_HIGHSPEED, do not switch card to
-        * HIGHSPEED mode even if the card support SD_HIGHSPPED.
-        * This can avoid furthur problem when the card runs in different
-        * mode between the host.
-        */
-       if (!((mmc->cfg->host_caps & MMC_MODE_HS_52MHz) &&
-               (mmc->cfg->host_caps & MMC_MODE_HS)))
-               return 0;
+       return 0;
+}
+
+static int sd_set_card_speed(struct mmc *mmc, enum bus_mode mode)
+{
+       int err;
+
+       ALLOC_CACHE_ALIGN_BUFFER(uint, switch_status, 16);
 
        err = sd_switch(mmc, SD_SWITCH_SWITCH, 0, 1, (u8 *)switch_status);
+       if (err)
+               return err;
+
+       if ((__be32_to_cpu(switch_status[4]) & 0x0f000000) != 0x01000000)
+               return -ENOTSUPP;
 
+       return 0;
+}
+
+int sd_select_bus_width(struct mmc *mmc, int w)
+{
+       int err;
+       struct mmc_cmd cmd;
+
+       if ((w != 4) && (w != 1))
+               return -EINVAL;
+
+       cmd.cmdidx = MMC_CMD_APP_CMD;
+       cmd.resp_type = MMC_RSP_R1;
+       cmd.cmdarg = mmc->rca << 16;
+
+       err = mmc_send_cmd(mmc, &cmd, NULL);
        if (err)
                return err;
 
-       if ((__be32_to_cpu(switch_status[4]) & 0x0f000000) == 0x01000000)
-               mmc->card_caps |= MMC_MODE_HS;
+       cmd.cmdidx = SD_CMD_APP_SET_BUS_WIDTH;
+       cmd.resp_type = MMC_RSP_R1;
+       if (w == 4)
+               cmd.cmdarg = 2;
+       else if (w == 1)
+               cmd.cmdarg = 0;
+       err = mmc_send_cmd(mmc, &cmd, NULL);
+       if (err)
+               return err;
 
        return 0;
 }
@@ -1133,6 +1161,18 @@ static const u8 multipliers[] = {
        80,
 };
 
+static inline int bus_width(uint cap)
+{
+       if (cap == MMC_MODE_8BIT)
+               return 8;
+       if (cap == MMC_MODE_4BIT)
+               return 4;
+       if (cap == MMC_MODE_1BIT)
+               return 1;
+       printf("invalid bus witdh capability 0x%x\n", cap);
+       return 0;
+}
+
 #if !CONFIG_IS_ENABLED(DM_MMC)
 static void mmc_set_ios(struct mmc *mmc)
 {
@@ -1176,8 +1216,9 @@ void mmc_dump_capabilities(const char *text, uint caps)
                printf("8, ");
        if (caps & MMC_MODE_4BIT)
                printf("4, ");
-       printf("1] modes [");
-
+       if (caps & MMC_MODE_1BIT)
+               printf("1, ");
+       printf("\b\b] modes [");
        for (mode = MMC_LEGACY; mode < MMC_MODES_END; mode++)
                if (MMC_CAP(mode) & caps)
                        printf("%s, ", mmc_mode_name(mode));
@@ -1185,47 +1226,81 @@ void mmc_dump_capabilities(const char *text, uint caps)
 }
 #endif
 
-static int sd_select_bus_freq_width(struct mmc *mmc)
+struct mode_width_tuning {
+       enum bus_mode mode;
+       uint widths;
+};
+
+static const struct mode_width_tuning sd_modes_by_pref[] = {
+       {
+               .mode = SD_HS,
+               .widths = MMC_MODE_4BIT | MMC_MODE_1BIT,
+       },
+       {
+               .mode = SD_LEGACY,
+               .widths = MMC_MODE_4BIT | MMC_MODE_1BIT,
+       }
+};
+
+#define for_each_sd_mode_by_pref(caps, mwt) \
+       for (mwt = sd_modes_by_pref;\
+            mwt < sd_modes_by_pref + ARRAY_SIZE(sd_modes_by_pref);\
+            mwt++) \
+               if (caps & MMC_CAP(mwt->mode))
+
+static int sd_select_mode_and_width(struct mmc *mmc)
 {
        int err;
-       struct mmc_cmd cmd;
+       uint widths[] = {MMC_MODE_4BIT, MMC_MODE_1BIT};
+       const struct mode_width_tuning *mwt;
 
-       err = sd_change_freq(mmc);
+       err = sd_get_capabilities(mmc);
        if (err)
                return err;
-
        /* Restrict card's capabilities by what the host can do */
-       mmc->card_caps &= mmc->cfg->host_caps;
-
-       if (mmc->card_caps & MMC_MODE_4BIT) {
-               cmd.cmdidx = MMC_CMD_APP_CMD;
-               cmd.resp_type = MMC_RSP_R1;
-               cmd.cmdarg = mmc->rca << 16;
-
-               err = mmc_send_cmd(mmc, &cmd, NULL);
-               if (err)
-                       return err;
-
-               cmd.cmdidx = SD_CMD_APP_SET_BUS_WIDTH;
-               cmd.resp_type = MMC_RSP_R1;
-               cmd.cmdarg = 2;
-               err = mmc_send_cmd(mmc, &cmd, NULL);
-               if (err)
-                       return err;
-
-               mmc_set_bus_width(mmc, 4);
+       mmc->card_caps &= (mmc->cfg->host_caps | MMC_MODE_1BIT);
+
+       for_each_sd_mode_by_pref(mmc->card_caps, mwt) {
+               uint *w;
+
+               for (w = widths; w < widths + ARRAY_SIZE(widths); w++) {
+                       if (*w & mmc->card_caps & mwt->widths) {
+                               debug("trying mode %s width %d (at %d MHz)\n",
+                                     mmc_mode_name(mwt->mode),
+                                     bus_width(*w),
+                                     mmc_mode2freq(mmc, mwt->mode) / 1000000);
+
+                               /* configure the bus width (card + host) */
+                               err = sd_select_bus_width(mmc, bus_width(*w));
+                               if (err)
+                                       goto error;
+                               mmc_set_bus_width(mmc, bus_width(*w));
+
+                               /* configure the bus mode (card) */
+                               err = sd_set_card_speed(mmc, mwt->mode);
+                               if (err)
+                                       goto error;
+
+                               /* configure the bus mode (host) */
+                               mmc_select_mode(mmc, mwt->mode);
+                               mmc_set_clock(mmc, mmc->tran_speed);
+
+                               err = sd_read_ssr(mmc);
+                               if (!err)
+                                       return 0;
+
+                               printf("bad ssr\n");
+
+error:
+                               /* revert to a safer bus speed */
+                               mmc_select_mode(mmc, SD_LEGACY);
+                               mmc_set_clock(mmc, mmc->tran_speed);
+                       }
+               }
        }
 
-       err = sd_read_ssr(mmc);
-       if (err)
-               return err;
-
-       if (mmc->card_caps & MMC_MODE_HS)
-               mmc_select_mode(mmc, SD_HS);
-       else
-               mmc_select_mode(mmc, SD_LEGACY);
-
-       return 0;
+       printf("unable to select a mode\n");
+       return -ENOTSUPP;
 }
 
 /*
@@ -1290,7 +1365,7 @@ static int mmc_select_bus_freq_width(struct mmc *mmc)
                return err;
 
        /* Restrict card's capabilities by what the host can do */
-       mmc->card_caps &= mmc->cfg->host_caps;
+       mmc->card_caps &= (mmc->cfg->host_caps | MMC_MODE_1BIT);
 
        /* Only version 4 of MMC supports wider bus widths */
        if (mmc->version < MMC_VERSION_4)
@@ -1685,7 +1760,7 @@ static int mmc_startup(struct mmc *mmc)
                return err;
 
        if (IS_SD(mmc))
-               err = sd_select_bus_freq_width(mmc);
+               err = sd_select_mode_and_width(mmc);
        else
                err = mmc_select_bus_freq_width(mmc);
 

diff --git a/include/mmc.h b/include/mmc.h
index dd83f14b6cd3e8f9283a757d0b37df2d3aa3b8f2..9fe6a87e882795cb323517698fa2a0db3d72cef8 100644 (file)
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -59,6 +59,7 @@
 
 #define MMC_MODE_8BIT          BIT(30)
 #define MMC_MODE_4BIT          BIT(29)
+#define MMC_MODE_1BIT          BIT(28)
 #define MMC_MODE_SPI           BIT(27)