mmc: rework selection of bus speed mode
authorSeungwon Jeon <tgih.jun@samsung.com>
Wed, 23 Apr 2014 08:08:44 +0000 (17:08 +0900)
committerChris Ball <chris@printf.net>
Mon, 12 May 2014 22:06:04 +0000 (18:06 -0400)
Current implementation for bus speed mode selection is too
complicated. This patch is to simplify the codes and remove
some duplicate parts.

The following changes are including:
* Adds functions for each mode selection(HS, HS-DDR, HS200 and etc)
* Rearranged the mode selection sequence with supported device type
* Adds maximum speed for HS200 mode(hs200_max_dtr)
* Adds field definition for HS_TIMING of EXT_CSD

Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Tested-by: Jaehoon Chung <jh80.chung@samsung.com>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>
drivers/mmc/core/debugfs.c
drivers/mmc/core/mmc.c
include/linux/mmc/card.h
include/linux/mmc/mmc.h

index 509229b..1f730db 100644 (file)
@@ -139,7 +139,7 @@ static int mmc_ios_show(struct seq_file *s, void *data)
                str = "mmc DDR52";
                break;
        case MMC_TIMING_MMC_HS200:
-               str = "mmc high-speed SDR200";
+               str = "mmc HS200";
                break;
        default:
                str = "invalid";
index 4538541..bec6786 100644 (file)
@@ -242,7 +242,7 @@ static void mmc_select_card_type(struct mmc_card *card)
        struct mmc_host *host = card->host;
        u8 card_type = card->ext_csd.raw_card_type & EXT_CSD_CARD_TYPE_MASK;
        u32 caps = host->caps, caps2 = host->caps2;
-       unsigned int hs_max_dtr = 0;
+       unsigned int hs_max_dtr = 0, hs200_max_dtr = 0;
        unsigned int avail_type = 0;
 
        if (caps & MMC_CAP_MMC_HIGHSPEED &&
@@ -271,17 +271,18 @@ static void mmc_select_card_type(struct mmc_card *card)
 
        if (caps2 & MMC_CAP2_HS200_1_8V_SDR &&
            card_type & EXT_CSD_CARD_TYPE_HS200_1_8V) {
-               hs_max_dtr = MMC_HS200_MAX_DTR;
+               hs200_max_dtr = MMC_HS200_MAX_DTR;
                avail_type |= EXT_CSD_CARD_TYPE_HS200_1_8V;
        }
 
        if (caps2 & MMC_CAP2_HS200_1_2V_SDR &&
            card_type & EXT_CSD_CARD_TYPE_HS200_1_2V) {
-               hs_max_dtr = MMC_HS200_MAX_DTR;
+               hs200_max_dtr = MMC_HS200_MAX_DTR;
                avail_type |= EXT_CSD_CARD_TYPE_HS200_1_2V;
        }
 
        card->ext_csd.hs_max_dtr = hs_max_dtr;
+       card->ext_csd.hs200_max_dtr = hs200_max_dtr;
        card->mmc_avail_type = avail_type;
 }
 
@@ -825,37 +826,46 @@ static int mmc_select_powerclass(struct mmc_card *card)
 }
 
 /*
- * Selects the desired buswidth and switch to the HS200 mode
- * if bus width set without error
+ * Set the bus speed for the selected speed mode.
  */
-static int mmc_select_hs200(struct mmc_card *card)
+static void mmc_set_bus_speed(struct mmc_card *card)
+{
+       unsigned int max_dtr = (unsigned int)-1;
+
+       if (mmc_card_hs200(card) && max_dtr > card->ext_csd.hs200_max_dtr)
+               max_dtr = card->ext_csd.hs200_max_dtr;
+       else if (mmc_card_hs(card) && max_dtr > card->ext_csd.hs_max_dtr)
+               max_dtr = card->ext_csd.hs_max_dtr;
+       else if (max_dtr > card->csd.max_dtr)
+               max_dtr = card->csd.max_dtr;
+
+       mmc_set_clock(card->host, max_dtr);
+}
+
+/*
+ * Select the bus width amoung 4-bit and 8-bit(SDR).
+ * If the bus width is changed successfully, return the selected width value.
+ * Zero is returned instead of error value if the wide width is not supported.
+ */
+static int mmc_select_bus_width(struct mmc_card *card)
 {
-       int idx, err = -EINVAL;
-       struct mmc_host *host;
        static unsigned ext_csd_bits[] = {
-               EXT_CSD_BUS_WIDTH_4,
                EXT_CSD_BUS_WIDTH_8,
+               EXT_CSD_BUS_WIDTH_4,
        };
        static unsigned bus_widths[] = {
-               MMC_BUS_WIDTH_4,
                MMC_BUS_WIDTH_8,
+               MMC_BUS_WIDTH_4,
        };
+       struct mmc_host *host = card->host;
+       unsigned idx, bus_width = 0;
+       int err = 0;
 
-       BUG_ON(!card);
-
-       host = card->host;
-
-       if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200_1_2V)
-               err = __mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_120);
-
-       if (err && card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200_1_8V)
-               err = __mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_180);
-
-       /* If fails try again during next card power cycle */
-       if (err)
-               goto err;
+       if ((card->csd.mmca_vsn < CSD_SPEC_VER_4) &&
+           !(host->caps & (MMC_CAP_4_BIT_DATA | MMC_CAP_8_BIT_DATA)))
+               return 0;
 
-       idx = (host->caps & MMC_CAP_8_BIT_DATA) ? 1 : 0;
+       idx = (host->caps & MMC_CAP_8_BIT_DATA) ? 0 : 1;
 
        /*
         * Unlike SD, MMC cards dont have a configuration register to notify
@@ -863,8 +873,7 @@ static int mmc_select_hs200(struct mmc_card *card)
         * the supported bus width or compare the ext csd values of current
         * bus width and ext csd values of 1 bit mode read earlier.
         */
-       for (; idx >= 0; idx--) {
-
+       for (; idx < ARRAY_SIZE(bus_widths); idx++) {
                /*
                 * Host is capable of 8bit transfer, then switch
                 * the device to work in 8bit transfer mode. If the
@@ -879,27 +888,202 @@ static int mmc_select_hs200(struct mmc_card *card)
                if (err)
                        continue;
 
-               mmc_set_bus_width(card->host, bus_widths[idx]);
+               bus_width = bus_widths[idx];
+               mmc_set_bus_width(host, bus_width);
 
+               /*
+                * If controller can't handle bus width test,
+                * compare ext_csd previously read in 1 bit mode
+                * against ext_csd at new bus width
+                */
                if (!(host->caps & MMC_CAP_BUS_WIDTH_TEST))
-                       err = mmc_compare_ext_csds(card, bus_widths[idx]);
+                       err = mmc_compare_ext_csds(card, bus_width);
                else
-                       err = mmc_bus_test(card, bus_widths[idx]);
-               if (!err)
+                       err = mmc_bus_test(card, bus_width);
+
+               if (!err) {
+                       err = bus_width;
                        break;
+               } else {
+                       pr_warn("%s: switch to bus width %d failed\n",
+                               mmc_hostname(host), ext_csd_bits[idx]);
+               }
        }
 
-       /* switch to HS200 mode if bus width set successfully */
+       return err;
+}
+
+/*
+ * Switch to the high-speed mode
+ */
+static int mmc_select_hs(struct mmc_card *card)
+{
+       int err;
+
+       err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+                          EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS,
+                          card->ext_csd.generic_cmd6_time,
+                          true, true, true);
        if (!err)
+               mmc_set_timing(card->host, MMC_TIMING_MMC_HS);
+
+       return err;
+}
+
+/*
+ * Activate wide bus and DDR if supported.
+ */
+static int mmc_select_hs_ddr(struct mmc_card *card)
+{
+       struct mmc_host *host = card->host;
+       u32 bus_width, ext_csd_bits;
+       int err = 0;
+
+       if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_DDR_52))
+               return 0;
+
+       bus_width = host->ios.bus_width;
+       if (bus_width == MMC_BUS_WIDTH_1)
+               return 0;
+
+       ext_csd_bits = (bus_width == MMC_BUS_WIDTH_8) ?
+               EXT_CSD_DDR_BUS_WIDTH_8 : EXT_CSD_DDR_BUS_WIDTH_4;
+
+       err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+                       EXT_CSD_BUS_WIDTH,
+                       ext_csd_bits,
+                       card->ext_csd.generic_cmd6_time);
+       if (err) {
+               pr_warn("%s: switch to bus width %d ddr failed\n",
+                       mmc_hostname(host), 1 << bus_width);
+               return err;
+       }
+
+       /*
+        * eMMC cards can support 3.3V to 1.2V i/o (vccq)
+        * signaling.
+        *
+        * EXT_CSD_CARD_TYPE_DDR_1_8V means 3.3V or 1.8V vccq.
+        *
+        * 1.8V vccq at 3.3V core voltage (vcc) is not required
+        * in the JEDEC spec for DDR.
+        *
+        * Do not force change in vccq since we are obviously
+        * working and no change to vccq is needed.
+        *
+        * WARNING: eMMC rules are NOT the same as SD DDR
+        */
+       if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_DDR_1_2V) {
+               err = __mmc_set_signal_voltage(host,
+                               MMC_SIGNAL_VOLTAGE_120);
+               if (err)
+                       return err;
+       }
+
+       mmc_set_timing(host, MMC_TIMING_MMC_DDR52);
+
+       return err;
+}
+
+/*
+ * For device supporting HS200 mode, the following sequence
+ * should be done before executing the tuning process.
+ * 1. set the desired bus width(4-bit or 8-bit, 1-bit is not supported)
+ * 2. switch to HS200 mode
+ * 3. set the clock to > 52Mhz and <=200MHz
+ */
+static int mmc_select_hs200(struct mmc_card *card)
+{
+       struct mmc_host *host = card->host;
+       int err = -EINVAL;
+
+       if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200_1_2V)
+               err = __mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_120);
+
+       if (err && card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200_1_8V)
+               err = __mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_180);
+
+       /* If fails try again during next card power cycle */
+       if (err)
+               goto err;
+
+       /*
+        * Set the bus width(4 or 8) with host's support and
+        * switch to HS200 mode if bus width is set successfully.
+        */
+       err = mmc_select_bus_width(card);
+       if (!IS_ERR_VALUE(err)) {
                err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
-                               EXT_CSD_HS_TIMING, 2,
-                               card->ext_csd.generic_cmd6_time,
-                               true, true, true);
+                                  EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS200,
+                                  card->ext_csd.generic_cmd6_time,
+                                  true, true, true);
+               if (!err)
+                       mmc_set_timing(host, MMC_TIMING_MMC_HS200);
+       }
 err:
        return err;
 }
 
 /*
+ * Activate High Speed or HS200 mode if supported.
+ */
+static int mmc_select_timing(struct mmc_card *card)
+{
+       int err = 0;
+
+       if ((card->csd.mmca_vsn < CSD_SPEC_VER_4 &&
+            card->ext_csd.hs_max_dtr == 0))
+               goto bus_speed;
+
+       if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)
+               err = mmc_select_hs200(card);
+       else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS)
+               err = mmc_select_hs(card);
+
+       if (err && err != -EBADMSG)
+               return err;
+
+       if (err) {
+               pr_warn("%s: switch to %s failed\n",
+                       mmc_card_hs(card) ? "high-speed" :
+                       (mmc_card_hs200(card) ? "hs200" : ""),
+                       mmc_hostname(card->host));
+               err = 0;
+       }
+
+bus_speed:
+       /*
+        * Set the bus speed to the selected bus timing.
+        * If timing is not selected, backward compatible is the default.
+        */
+       mmc_set_bus_speed(card);
+       return err;
+}
+
+/*
+ * Execute tuning sequence to seek the proper bus operating
+ * conditions for HS200, which sends CMD21 to the device.
+ */
+static int mmc_hs200_tuning(struct mmc_card *card)
+{
+       struct mmc_host *host = card->host;
+       int err = 0;
+
+       if (host->ops->execute_tuning) {
+               mmc_host_clk_hold(host);
+               err = host->ops->execute_tuning(host,
+                               MMC_SEND_TUNING_BLOCK_HS200);
+               mmc_host_clk_release(host);
+
+               if (err)
+                       pr_warn("%s: tuning execution failed\n",
+                               mmc_hostname(host));
+       }
+
+       return err;
+}
+
+/*
  * Handle the detection and initialisation of a card.
  *
  * In the case of a resume, "oldcard" will contain the card
@@ -909,9 +1093,8 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
        struct mmc_card *oldcard)
 {
        struct mmc_card *card;
-       int err, ddr = 0;
+       int err;
        u32 cid[4];
-       unsigned int max_dtr;
        u32 rocr;
        u8 *ext_csd = NULL;
 
@@ -1103,173 +1286,23 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
        }
 
        /*
-        * Activate high speed (if supported)
-        */
-       if (card->ext_csd.hs_max_dtr != 0) {
-               err = 0;
-               if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)
-                       err = mmc_select_hs200(card);
-               else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS)
-                       err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
-                                       EXT_CSD_HS_TIMING, 1,
-                                       card->ext_csd.generic_cmd6_time,
-                                       true, true, true);
-
-               if (err && err != -EBADMSG)
-                       goto free_card;
-
-               if (err) {
-                       pr_warning("%s: switch to highspeed failed\n",
-                              mmc_hostname(card->host));
-                       err = 0;
-               } else {
-                       if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)
-                               mmc_set_timing(card->host,
-                                              MMC_TIMING_MMC_HS200);
-                       else
-                               mmc_set_timing(card->host, MMC_TIMING_MMC_HS);
-               }
-       }
-
-       /*
-        * Compute bus speed.
-        */
-       max_dtr = (unsigned int)-1;
-
-       if (mmc_card_hs(card) || mmc_card_hs200(card)) {
-               if (max_dtr > card->ext_csd.hs_max_dtr)
-                       max_dtr = card->ext_csd.hs_max_dtr;
-               if (mmc_card_hs(card) && (max_dtr > 52000000))
-                       max_dtr = 52000000;
-       } else if (max_dtr > card->csd.max_dtr) {
-               max_dtr = card->csd.max_dtr;
-       }
-
-       mmc_set_clock(host, max_dtr);
-
-       /*
-        * Indicate DDR mode (if supported).
+        * Select timing interface
         */
-       if (mmc_card_hs(card))
-               ddr = card->mmc_avail_type & EXT_CSD_CARD_TYPE_DDR_52;
+       err = mmc_select_timing(card);
+       if (err)
+               goto free_card;
 
-       /*
-        * Indicate HS200 SDR mode (if supported).
-        */
        if (mmc_card_hs200(card)) {
-               u32 ext_csd_bits;
-               u32 bus_width = card->host->ios.bus_width;
-
-               /*
-                * For devices supporting HS200 mode, the bus width has
-                * to be set before executing the tuning function. If
-                * set before tuning, then device will respond with CRC
-                * errors for responses on CMD line. So for HS200 the
-                * sequence will be
-                * 1. set bus width 4bit / 8 bit (1 bit not supported)
-                * 2. switch to HS200 mode
-                * 3. set the clock to > 52Mhz <=200MHz and
-                * 4. execute tuning for HS200
-                */
-               if (card->host->ops->execute_tuning) {
-                       mmc_host_clk_hold(card->host);
-                       err = card->host->ops->execute_tuning(card->host,
-                               MMC_SEND_TUNING_BLOCK_HS200);
-                       mmc_host_clk_release(card->host);
-               }
-               if (err) {
-                       pr_warning("%s: tuning execution failed\n",
-                                  mmc_hostname(card->host));
+               err = mmc_hs200_tuning(card);
+               if (err)
                        goto err;
-               }
-
-               ext_csd_bits = (bus_width == MMC_BUS_WIDTH_8) ?
-                               EXT_CSD_BUS_WIDTH_8 : EXT_CSD_BUS_WIDTH_4;
-       }
-
-       /*
-        * Activate wide bus and DDR (if supported).
-        */
-       if (!mmc_card_hs200(card) &&
-           (card->csd.mmca_vsn >= CSD_SPEC_VER_4) &&
-           (host->caps & (MMC_CAP_4_BIT_DATA | MMC_CAP_8_BIT_DATA))) {
-               static unsigned ext_csd_bits[][2] = {
-                       { EXT_CSD_BUS_WIDTH_8, EXT_CSD_DDR_BUS_WIDTH_8 },
-                       { EXT_CSD_BUS_WIDTH_4, EXT_CSD_DDR_BUS_WIDTH_4 },
-                       { EXT_CSD_BUS_WIDTH_1, EXT_CSD_BUS_WIDTH_1 },
-               };
-               static unsigned bus_widths[] = {
-                       MMC_BUS_WIDTH_8,
-                       MMC_BUS_WIDTH_4,
-                       MMC_BUS_WIDTH_1
-               };
-               unsigned idx, bus_width = 0;
-
-               if (host->caps & MMC_CAP_8_BIT_DATA)
-                       idx = 0;
-               else
-                       idx = 1;
-               for (; idx < ARRAY_SIZE(bus_widths); idx++) {
-                       bus_width = bus_widths[idx];
-                       if (bus_width == MMC_BUS_WIDTH_1)
-                               ddr = 0; /* no DDR for 1-bit width */
-
-                       err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
-                                        EXT_CSD_BUS_WIDTH,
-                                        ext_csd_bits[idx][0],
-                                        card->ext_csd.generic_cmd6_time);
-                       if (!err) {
-                               mmc_set_bus_width(card->host, bus_width);
-
-                               /*
-                                * If controller can't handle bus width test,
-                                * compare ext_csd previously read in 1 bit mode
-                                * against ext_csd at new bus width
-                                */
-                               if (!(host->caps & MMC_CAP_BUS_WIDTH_TEST))
-                                       err = mmc_compare_ext_csds(card,
-                                               bus_width);
-                               else
-                                       err = mmc_bus_test(card, bus_width);
-                               if (!err)
-                                       break;
-                       }
-               }
-
-               if (!err && ddr) {
-                       err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
-                                        EXT_CSD_BUS_WIDTH,
-                                        ext_csd_bits[idx][1],
-                                        card->ext_csd.generic_cmd6_time);
-               }
-               if (err) {
-                       pr_warning("%s: switch to bus width %d ddr %d "
-                               "failed\n", mmc_hostname(card->host),
-                               1 << bus_width, ddr);
-                       goto free_card;
-               } else if (ddr) {
-                       /*
-                        * eMMC cards can support 3.3V to 1.2V i/o (vccq)
-                        * signaling.
-                        *
-                        * EXT_CSD_CARD_TYPE_DDR_1_8V means 3.3V or 1.8V vccq.
-                        *
-                        * 1.8V vccq at 3.3V core voltage (vcc) is not required
-                        * in the JEDEC spec for DDR.
-                        *
-                        * Do not force change in vccq since we are obviously
-                        * working and no change to vccq is needed.
-                        *
-                        * WARNING: eMMC rules are NOT the same as SD DDR
-                        */
-                       if (ddr & EXT_CSD_CARD_TYPE_DDR_1_2V) {
-                               err = __mmc_set_signal_voltage(host,
-                                       MMC_SIGNAL_VOLTAGE_120);
-                               if (err)
-                                       goto err;
-                       }
-                       mmc_set_timing(card->host, MMC_TIMING_MMC_DDR52);
-                       mmc_set_bus_width(card->host, bus_width);
+       } else if (mmc_card_hs(card)) {
+               /* Select the desired bus width optionally */
+               err = mmc_select_bus_width(card);
+               if (!IS_ERR_VALUE(err)) {
+                       err = mmc_select_hs_ddr(card);
+                       if (err)
+                               goto err;
                }
        }
 
index fe31f8d..1760736 100644 (file)
@@ -63,6 +63,7 @@ struct mmc_ext_csd {
        unsigned int            power_off_longtime;     /* Units: ms */
        u8                      power_off_notification; /* state */
        unsigned int            hs_max_dtr;
+       unsigned int            hs200_max_dtr;
 #define MMC_HIGH_26_MAX_DTR    26000000
 #define MMC_HIGH_52_MAX_DTR    52000000
 #define MMC_HIGH_DDR_MAX_DTR   52000000
index f734c0c..f429f13 100644 (file)
@@ -377,6 +377,10 @@ struct _mmc_csd {
 #define EXT_CSD_DDR_BUS_WIDTH_4        5       /* Card is in 4 bit DDR mode */
 #define EXT_CSD_DDR_BUS_WIDTH_8        6       /* Card is in 8 bit DDR mode */
 
+#define EXT_CSD_TIMING_BC      0       /* Backwards compatility */
+#define EXT_CSD_TIMING_HS      1       /* High speed */
+#define EXT_CSD_TIMING_HS200   2       /* HS200 */
+
 #define EXT_CSD_SEC_ER_EN      BIT(0)
 #define EXT_CSD_SEC_BD_BLK_EN  BIT(2)
 #define EXT_CSD_SEC_GB_CL_EN   BIT(4)