rpi3: sdhost: SDHost driver improvement
This commit improves the SDHost driver for RPi3 as following:
* Unblock MMC_CMD(17). Using MMC_CMD(17) is more efficient on
block reading.
* In some low probability that SEND_OP_COND might results CRC7
error. We can consider that the command runs correctly. We don't
need to retry this command so removing the code for retry.
* Using MMC_BUS_WIDTH_1 as MMC default value to improve the stability.
* Increase the clock to 50Mhz in data mode to speed up the io.
* Change the pull resistors configuration to gain more stability.
Signed-off-by: Ying-Chun Liu (PaulLiu) <paulliu@debian.org>
diff --git a/drivers/rpi3/sdhost/rpi3_sdhost.c b/drivers/rpi3/sdhost/rpi3_sdhost.c
index efcd6db..c4b6fca 100644
--- a/drivers/rpi3/sdhost/rpi3_sdhost.c
+++ b/drivers/rpi3/sdhost/rpi3_sdhost.c
@@ -272,8 +272,6 @@
}
cmd_idx = cmd->cmd_idx & HC_CMD_COMMAND_MASK;
- if (cmd_idx == MMC_CMD(17))
- cmd_idx = MMC_CMD(18);
cmd_arg = cmd->cmd_arg;
if (cmd_idx == MMC_ACMD(51)) {
@@ -364,8 +362,12 @@
mmio_write_32(reg_base + HC_HOSTSTATUS,
HC_HSTST_MASK_ERROR_ALL);
+ /*
+ * If the command SEND_OP_COND returns with CRC7 error,
+ * it can be considered as having completed successfully.
+ */
if (!(sdhsts & HC_HSTST_ERROR_CRC7)
- || (cmd_idx != MMC_ACMD(51))) {
+ || (cmd_idx != MMC_CMD(1))) {
if (sdhsts & HC_HSTST_TIMEOUT_CMD) {
ERROR("rpi3_sdhost: timeout status 0x%x\n",
sdhsts);
@@ -533,21 +535,6 @@
if (rpi3_sdhost_params.current_cmd == MMC_CMD(18))
send_command_decorated(MMC_CMD(12), 0);
- if (err == -(EILSEQ)) {
- const int max_retries = 20;
- int r;
-
- rpi3_sdhost_params.crc_err_retries++;
- if (rpi3_sdhost_params.crc_err_retries < max_retries) {
- /* retries if there's an CRC error */
- r = rpi3_sdhost_prepare(lba, buf, size);
- send_command_decorated(MMC_CMD(18), lba);
- r = rpi3_sdhost_read(lba, buf, size);
- if (r == 0)
- err = 0;
- }
- }
-
return err;
}
@@ -617,16 +604,20 @@
}
/* setting pull resistors for 48 to 53.
- * GPIO 48 (SD_CLK) to GPIO_PULL_UP
- * GPIO 49 (SD_CMD) to GPIO_PULL_NONE
- * GPIO 50 (SD_D0) to GPIO_PULL_NONE
- * GPIO 51 (SD_D1) to GPIO_PULL_NONE
- * GPIO 52 (SD_D2) to GPIO_PULL_NONE
- * GPIO 53 (SD_D3) to GPIO_PULL_NONE
+ * It is debatable to set SD_CLK to UP or NONE. We massively
+ * tested different brands of SD Cards and found NONE works
+ * most stable.
+ *
+ * GPIO 48 (SD_CLK) to GPIO_PULL_NONE
+ * GPIO 49 (SD_CMD) to GPIO_PULL_UP
+ * GPIO 50 (SD_D0) to GPIO_PULL_UP
+ * GPIO 51 (SD_D1) to GPIO_PULL_UP
+ * GPIO 52 (SD_D2) to GPIO_PULL_UP
+ * GPIO 53 (SD_D3) to GPIO_PULL_UP
*/
- gpio_set_pull(48, GPIO_PULL_UP);
+ gpio_set_pull(48, GPIO_PULL_NONE);
for (int i = 49; i <= 53; i++)
- gpio_set_pull(i, GPIO_PULL_NONE);
+ gpio_set_pull(i, GPIO_PULL_UP);
/* Set pin 48-53 to alt-0. It means route SDHOST to card slot */
for (int i = 48; i <= 53; i++)
@@ -675,15 +666,14 @@
rpi3_sdhost_params.gpio48_pinselect[i-48]);
}
- /* Must reset the pull resistors for u-boot to work.
- * GPIO 48 (SD_CLK) to GPIO_PULL_NONE
+ /* Reset the pull resistors before entering BL33.
+ * GPIO 48 (SD_CLK) to GPIO_PULL_UP
* GPIO 49 (SD_CMD) to GPIO_PULL_UP
* GPIO 50 (SD_D0) to GPIO_PULL_UP
* GPIO 51 (SD_D1) to GPIO_PULL_UP
* GPIO 52 (SD_D2) to GPIO_PULL_UP
* GPIO 53 (SD_D3) to GPIO_PULL_UP
*/
- gpio_set_pull(48, GPIO_PULL_NONE);
- for (int i = 49; i <= 53; i++)
+ for (int i = 48; i <= 53; i++)
gpio_set_pull(i, GPIO_PULL_UP);
}