[U-Boot] [PATCH 09/22] mmc: refactor SD startup to make it easier to support new modes
Jean-Jacques Hiblot
jjhiblot at ti.com
Fri May 12 18:16:27 UTC 2017
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 at ti.com>
---
drivers/mmc/mmc.c | 180 ++++++++++++++++++++++++++++++++++++++----------------
include/mmc.h | 1 +
2 files changed, 128 insertions(+), 53 deletions(-)
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index dc7985f..f42a0fe 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -608,7 +608,7 @@ 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;
@@ -934,7 +934,7 @@ 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;
@@ -943,7 +943,7 @@ 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;
@@ -1020,26 +1020,53 @@ 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)
- mmc->card_caps |= MMC_MODE_HS;
+ 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;
+
+ 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;
}
@@ -1131,6 +1158,19 @@ 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;
+ error("invalid bus witdh capability 0x%x\n", cap);
+ return 0;
+}
+
#ifndef CONFIG_DM_MMC_OPS
static void mmc_set_ios(struct mmc *mmc)
{
@@ -1168,55 +1208,89 @@ 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));
printf("\b\b]\n");
}
-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;
+ else
+ 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;
+ error("unable to select a mode\n");
+ return -ENOTSUPP;
}
static int mmc_read_and_compare_ext_csd(struct mmc *mmc)
@@ -1277,7 +1351,7 @@ 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)
@@ -1671,7 +1745,7 @@ 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 afda02d..1ffa7ec 100644
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -59,6 +59,7 @@
#define MMC_MODE_8BIT (1 << 30)
#define MMC_MODE_4BIT (1 << 29)
+#define MMC_MODE_1BIT (1 << 28)
#define MMC_MODE_SPI (1 << 27)
--
1.9.1
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