mmc: Test bus-width for old MMC devices
Some old MMC devices fail with the 4/8 bits the driver tries to use
exclusively. This patch adds a test for the given bus setup and falls
back to the lower bit mode (until 1-bit mode) when the test fails.
[Major rework and refactoring by tiwai]
[Quirk addition and many fixes by prakity]
Signed-off-by: Aries Lee <arieslee@jmicron.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Philip Rakity <prakity@marvell.com>
Tested-by: Philip Rakity <prakity@marvell.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 76bb621..1d8409f 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -534,39 +534,57 @@
*/
if ((card->csd.mmca_vsn >= CSD_SPEC_VER_4) &&
(host->caps & (MMC_CAP_4_BIT_DATA | MMC_CAP_8_BIT_DATA))) {
- unsigned ext_csd_bit, bus_width;
+ 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) {
- if (ddr)
- ext_csd_bit = EXT_CSD_DDR_BUS_WIDTH_8;
- else
- ext_csd_bit = EXT_CSD_BUS_WIDTH_8;
- bus_width = MMC_BUS_WIDTH_8;
- } else {
- if (ddr)
- ext_csd_bit = EXT_CSD_DDR_BUS_WIDTH_4;
- else
- ext_csd_bit = EXT_CSD_BUS_WIDTH_4;
- bus_width = MMC_BUS_WIDTH_4;
+ 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]);
+ if (!err) {
+ /*
+ * If controller can't handle bus width test,
+ * use the highest bus width to maintain
+ * compatibility with previous MMC behavior.
+ */
+ if (!(host->caps & MMC_CAP_BUS_WIDTH_TEST))
+ break;
+ mmc_set_bus_width_ddr(card->host,
+ bus_width, MMC_SDR_MODE);
+ err = mmc_bus_test(card, bus_width);
+ if (!err)
+ break;
+ }
}
- err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
- EXT_CSD_BUS_WIDTH, ext_csd_bit);
-
- if (err && err != -EBADMSG)
- goto free_card;
-
+ if (!err && ddr) {
+ err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+ EXT_CSD_BUS_WIDTH,
+ ext_csd_bits[idx][1]);
+ }
if (err) {
printk(KERN_WARNING "%s: switch to bus width %d ddr %d "
- "failed\n", mmc_hostname(card->host),
- 1 << bus_width, ddr);
- err = 0;
- } else {
- if (ddr)
- mmc_card_set_ddr_mode(card);
- else
- ddr = MMC_SDR_MODE;
-
+ "failed\n", mmc_hostname(card->host),
+ 1 << bus_width, ddr);
+ goto free_card;
+ } else if (ddr) {
+ mmc_card_set_ddr_mode(card);
mmc_set_bus_width_ddr(card->host, bus_width, ddr);
}
}
