mmc: core: add support for eMMC Dual Data Rate
eMMC voltage change not required for 1.8V. 3.3V and 1.8V vcc
are capable of doing DDR. vccq of 1.8v is not required.
Signed-off-by: Philip Rakity <prakity@marvell.com>
Reviewed-by: Arindam Nath <arindam.nath@amd.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index a2c795e..0433fe6 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -20,6 +20,7 @@
#include "core.h"
#include "bus.h"
#include "mmc_ops.h"
+#include "sd_ops.h"
static const unsigned int tran_exp[] = {
10000, 100000, 1000000, 10000000,
@@ -633,10 +634,14 @@
*/
if (mmc_card_highspeed(card)) {
if ((card->ext_csd.card_type & EXT_CSD_CARD_TYPE_DDR_1_8V)
- && (host->caps & (MMC_CAP_1_8V_DDR)))
+ && ((host->caps & (MMC_CAP_1_8V_DDR |
+ MMC_CAP_UHS_DDR50))
+ == (MMC_CAP_1_8V_DDR | MMC_CAP_UHS_DDR50)))
ddr = MMC_1_8V_DDR_MODE;
else if ((card->ext_csd.card_type & EXT_CSD_CARD_TYPE_DDR_1_2V)
- && (host->caps & (MMC_CAP_1_2V_DDR)))
+ && ((host->caps & (MMC_CAP_1_2V_DDR |
+ MMC_CAP_UHS_DDR50))
+ == (MMC_CAP_1_2V_DDR | MMC_CAP_UHS_DDR50)))
ddr = MMC_1_2V_DDR_MODE;
}
@@ -670,8 +675,7 @@
ext_csd_bits[idx][0],
0);
if (!err) {
- mmc_set_bus_width_ddr(card->host,
- bus_width, MMC_SDR_MODE);
+ mmc_set_bus_width(card->host, bus_width);
/*
* If controller can't handle bus width test,
* use the highest bus width to maintain
@@ -697,8 +701,29 @@
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, 0);
+ if (err)
+ goto err;
+ }
mmc_card_set_ddr_mode(card);
- mmc_set_bus_width_ddr(card->host, bus_width, ddr);
+ mmc_set_timing(card->host, MMC_TIMING_UHS_DDR50);
+ mmc_set_bus_width(card->host, bus_width);
}
}
