[U-Boot] [PATCH 10/22] mmc: refactor MMC startup to make it easier to support new modes
Jean-Jacques Hiblot
jjhiblot at ti.com
Fri May 12 18:16:28 UTC 2017
The MMC startup process currently handles 4 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 at ti.com>
---
drivers/mmc/mmc.c | 238 +++++++++++++++++++++++++++++++++---------------------
include/mmc.h | 15 +++-
2 files changed, 157 insertions(+), 96 deletions(-)
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index f42a0fe..2931871 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -200,6 +200,7 @@ static int mmc_select_mode(struct mmc *mmc, enum bus_mode mode)
{
mmc->selected_mode = mode;
mmc->tran_speed = mmc_mode2freq(mmc, mode);
+ mmc->ddr_mode = mmc_is_mode_ddr(mode);
debug("selecting mode %s (freq : %d MHz)\n", mmc_mode_name(mode),
mmc->tran_speed / 1000000);
return 0;
@@ -602,11 +603,46 @@ int mmc_switch(struct mmc *mmc, u8 set, u8 index, u8 value)
}
-static int mmc_change_freq(struct mmc *mmc)
+static int mmc_set_card_speed(struct mmc *mmc, enum bus_mode mode)
{
- ALLOC_CACHE_ALIGN_BUFFER(u8, ext_csd, MMC_MAX_BLOCK_LEN);
- char cardtype;
int err;
+ int speed_bits;
+ ALLOC_CACHE_ALIGN_BUFFER(u8, test_csd, MMC_MAX_BLOCK_LEN);
+
+ switch (mode) {
+ case MMC_HS:
+ case MMC_HS_52:
+ case MMC_DDR_52:
+ speed_bits = EXT_CSD_TIMING_HS;
+ case MMC_LEGACY:
+ speed_bits = EXT_CSD_TIMING_LEGACY;
+ break;
+ default:
+ return -EINVAL;
+ }
+ err = mmc_switch(mmc, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING,
+ speed_bits);
+ if (err)
+ return err;
+
+ if ((mode == MMC_HS) || (mode == MMC_HS_52)) {
+ /* Now check to see that it worked */
+ err = mmc_send_ext_csd(mmc, test_csd);
+ if (err)
+ return err;
+
+ /* No high-speed support */
+ if (!test_csd[EXT_CSD_HS_TIMING])
+ return -ENOTSUPP;
+ }
+
+ return 0;
+}
+
+static int mmc_get_capabilities(struct mmc *mmc)
+{
+ u8 *ext_csd = mmc->ext_csd;
+ char cardtype;
mmc->card_caps = MMC_MODE_1BIT;
@@ -617,38 +653,23 @@ static int mmc_change_freq(struct mmc *mmc)
if (mmc->version < MMC_VERSION_4)
return 0;
- mmc->card_caps |= MMC_MODE_4BIT | MMC_MODE_8BIT;
-
- err = mmc_send_ext_csd(mmc, ext_csd);
+ if (!ext_csd) {
+ error("No ext_csd found!\n"); /* this should enver happen */
+ return -ENOTSUPP;
+ }
- if (err)
- return err;
+ mmc->card_caps |= MMC_MODE_4BIT | MMC_MODE_8BIT;
cardtype = ext_csd[EXT_CSD_CARD_TYPE] & 0xf;
- err = mmc_switch(mmc, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING, 1);
-
- if (err)
- return err;
-
- /* Now check to see that it worked */
- err = mmc_send_ext_csd(mmc, ext_csd);
-
- if (err)
- return err;
-
- /* No high-speed support */
- if (!ext_csd[EXT_CSD_HS_TIMING])
- return 0;
-
/* High Speed is set, there are two types: 52MHz and 26MHz */
if (cardtype & EXT_CSD_CARD_TYPE_52) {
- if (cardtype & EXT_CSD_CARD_TYPE_DDR_1_8V)
+ if (cardtype & EXT_CSD_CARD_TYPE_DDR_52)
mmc->card_caps |= MMC_MODE_DDR_52MHz;
- mmc->card_caps |= MMC_MODE_HS_52MHz | MMC_MODE_HS;
- } else {
- mmc->card_caps |= MMC_MODE_HS;
+ mmc->card_caps |= MMC_MODE_HS_52MHz;
}
+ if (cardtype & EXT_CSD_CARD_TYPE_26)
+ mmc->card_caps |= MMC_MODE_HS;
return 0;
}
@@ -1320,33 +1341,58 @@ static int mmc_read_and_compare_ext_csd(struct mmc *mmc)
}
-static int mmc_select_bus_freq_width(struct mmc *mmc)
+static const struct mode_width_tuning mmc_modes_by_pref[] = {
+ {
+ .mode = MMC_HS_200,
+ .widths = MMC_MODE_8BIT | MMC_MODE_4BIT,
+ },
+ {
+ .mode = MMC_DDR_52,
+ .widths = MMC_MODE_8BIT | MMC_MODE_4BIT,
+ },
+ {
+ .mode = MMC_HS_52,
+ .widths = MMC_MODE_8BIT | MMC_MODE_4BIT | MMC_MODE_1BIT,
+ },
+ {
+ .mode = MMC_HS,
+ .widths = MMC_MODE_8BIT | MMC_MODE_4BIT | MMC_MODE_1BIT,
+ },
+ {
+ .mode = MMC_LEGACY,
+ .widths = MMC_MODE_8BIT | MMC_MODE_4BIT | MMC_MODE_1BIT,
+ }
+};
+#define for_each_mmc_mode_by_pref(caps, mwt) \
+ for (mwt = mmc_modes_by_pref;\
+ mwt < mmc_modes_by_pref + ARRAY_SIZE(mmc_modes_by_pref);\
+ mwt++) \
+ if (caps & MMC_CAP(mwt->mode))
+
+static const struct ext_csd_bus_width {
+ uint cap;
+ bool is_ddr;
+ uint ext_csd_bits;
+} ext_csd_bus_width[] = {
+ {MMC_MODE_8BIT, true, EXT_CSD_BUS_WIDTH_8 | EXT_CSD_DDR},
+ {MMC_MODE_4BIT, true, EXT_CSD_BUS_WIDTH_4 | EXT_CSD_DDR},
+ {MMC_MODE_8BIT, false, EXT_CSD_BUS_WIDTH_8},
+ {MMC_MODE_4BIT, false, EXT_CSD_BUS_WIDTH_4},
+ {MMC_MODE_1BIT, false, EXT_CSD_BUS_WIDTH_1},
+};
+#define for_each_supported_width(caps, ddr, ecbv) \
+ for (ecbv = ext_csd_bus_width;\
+ ecbv < ext_csd_bus_width + ARRAY_SIZE(ext_csd_bus_width);\
+ ecbv++) \
+ if ((ddr == ecbv->is_ddr) && (caps & ecbv->cap))
+
+static int mmc_select_mode_and_width(struct mmc *mmc)
{
- /* An array of possible bus widths in order of preference */
- static const unsigned ext_csd_bits[] = {
- EXT_CSD_DDR_BUS_WIDTH_8,
- EXT_CSD_DDR_BUS_WIDTH_4,
- EXT_CSD_BUS_WIDTH_8,
- EXT_CSD_BUS_WIDTH_4,
- EXT_CSD_BUS_WIDTH_1,
- };
- /* An array to map CSD bus widths to host cap bits */
- static const unsigned ext_to_hostcaps[] = {
- [EXT_CSD_DDR_BUS_WIDTH_4] =
- MMC_MODE_DDR_52MHz | MMC_MODE_4BIT,
- [EXT_CSD_DDR_BUS_WIDTH_8] =
- MMC_MODE_DDR_52MHz | MMC_MODE_8BIT,
- [EXT_CSD_BUS_WIDTH_4] = MMC_MODE_4BIT,
- [EXT_CSD_BUS_WIDTH_8] = MMC_MODE_8BIT,
- };
- /* An array to map chosen bus width to an integer */
- static const unsigned widths[] = {
- 8, 4, 8, 4, 1,
- };
int err;
- int idx;
+ const struct mode_width_tuning *mwt;
+ const struct ext_csd_bus_width *ecbw;
- err = mmc_change_freq(mmc);
+ err = mmc_get_capabilities(mmc);
if (err)
return err;
@@ -1357,60 +1403,64 @@ static int mmc_select_bus_freq_width(struct mmc *mmc)
if (mmc->version < MMC_VERSION_4)
return 0;
+
if (!mmc->ext_csd) {
error("No ext_csd found!\n"); /* this should enver happen */
return -ENOTSUPP;
}
- for (idx = 0; idx < ARRAY_SIZE(ext_csd_bits); idx++) {
- unsigned int extw = ext_csd_bits[idx];
- unsigned int caps = ext_to_hostcaps[extw];
+ for_each_mmc_mode_by_pref(mmc->card_caps, mwt) {
+ for_each_supported_width(mmc->card_caps & mwt->widths,
+ mmc_is_mode_ddr(mwt->mode), ecbw) {
+ debug("trying mode %s width %d (at %d MHz)\n",
+ mmc_mode_name(mwt->mode),
+ bus_width(ecbw->cap),
+ mmc_mode2freq(mmc, mwt->mode) / 1000000);
- /*
- * If the bus width is still not changed,
- * don't try to set the default again.
- * Otherwise, recover from switch attempts
- * by switching to 1-bit bus width.
- */
- if (extw == EXT_CSD_BUS_WIDTH_1 &&
- mmc->bus_width == 1) {
- err = 0;
- break;
- }
-
- /*
- * Check to make sure the card and controller support
- * these capabilities
- */
- if ((mmc->card_caps & caps) != caps)
- continue;
-
- err = mmc_switch(mmc, EXT_CSD_CMD_SET_NORMAL,
- EXT_CSD_BUS_WIDTH, extw);
+ /* configure the bus width (card + host) */
+ err = mmc_switch(mmc, EXT_CSD_CMD_SET_NORMAL,
+ EXT_CSD_BUS_WIDTH,
+ ecbw->ext_csd_bits & ~EXT_CSD_DDR);
+ if (err)
+ goto error;
+ mmc_set_bus_width(mmc, bus_width(ecbw->cap));
- if (err)
- continue;
+ /* configure the bus speed (card) */
+ err = mmc_set_card_speed(mmc, mwt->mode);
+ if (err)
+ goto error;
+
+ /*
+ * configure the bus width AND the ddr mode (card)
+ * The host side will be taken care of in the next step
+ */
+ if (ecbw->ext_csd_bits & EXT_CSD_DDR) {
+ err = mmc_switch(mmc, EXT_CSD_CMD_SET_NORMAL,
+ EXT_CSD_BUS_WIDTH, ecbw->ext_csd_bits);
+ if (err)
+ goto error;
+ }
- mmc->ddr_mode = (caps & MMC_MODE_DDR_52MHz) ? 1 : 0;
- mmc_set_bus_width(mmc, widths[idx]);
+ /* configure the bus mode (host) */
+ mmc_select_mode(mmc, mwt->mode);
+ mmc_set_clock(mmc, mmc->tran_speed);
- err = mmc_read_and_compare_ext_csd(mmc);
- if (!err)
- break;
+ /* do a transfer to check the configuration */
+ err = mmc_read_and_compare_ext_csd(mmc);
+ if (!err)
+ return 0;
+error:
+ /* if an error occured, revert to a safer bus mode */
+ mmc_switch(mmc, EXT_CSD_CMD_SET_NORMAL,
+ EXT_CSD_BUS_WIDTH, EXT_CSD_BUS_WIDTH_1);
+ mmc_select_mode(mmc, MMC_LEGACY);
+ mmc_set_bus_width(mmc, 1);
+ }
}
- if (err)
- return err;
-
- if (mmc->card_caps & MMC_MODE_HS_52MHz) {
- if (mmc->ddr_mode)
- mmc_select_mode(mmc, MMC_DDR_52);
- else
- mmc_select_mode(mmc, MMC_HS_52);
- } else if (mmc->card_caps & MMC_MODE_HS)
- mmc_select_mode(mmc, MMC_HS);
+ error("unable to select a mode\n");
- return err;
+ return -ENOTSUPP;
}
static int mmc_startup_v4(struct mmc *mmc)
@@ -1747,7 +1797,7 @@ static int mmc_startup(struct mmc *mmc)
if (IS_SD(mmc))
err = sd_select_mode_and_width(mmc);
else
- err = mmc_select_bus_freq_width(mmc);
+ err = mmc_select_mode_and_width(mmc);
if (err)
return err;
diff --git a/include/mmc.h b/include/mmc.h
index 1ffa7ec..3c6971d 100644
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -213,9 +213,10 @@
#define EXT_CSD_BUS_WIDTH_1 0 /* Card is in 1 bit mode */
#define EXT_CSD_BUS_WIDTH_4 1 /* Card is in 4 bit mode */
#define EXT_CSD_BUS_WIDTH_8 2 /* Card is in 8 bit mode */
-#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_DDR 4 /* Card is in DDR mode */
+#define EXT_CSD_TIMING_LEGACY 0 /* no high speed */
+#define EXT_CSD_TIMING_HS 1 /* HS */
#define EXT_CSD_BOOT_ACK_ENABLE (1 << 6)
#define EXT_CSD_BOOT_PARTITION_ENABLE (1 << 3)
#define EXT_CSD_PARTITION_ACCESS_ENABLE (1 << 0)
@@ -424,6 +425,16 @@ enum bus_mode {
const char *mmc_mode_name(enum bus_mode mode);
void mmc_dump_capabilities(const char *text, uint caps);
+
+static inline bool mmc_is_mode_ddr(enum bus_mode mode)
+{
+ if ((mode == MMC_DDR_52) || (mode == UHS_DDR50))
+ return true;
+ else
+ return false;
+}
+
+
/*
* With CONFIG_DM_MMC enabled, struct mmc can be accessed from the MMC device
* with mmc_get_mmc_dev().
--
1.9.1
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