From: Bin Meng <[email protected]>
Per the "Physical Layer Specification Version 8.00" chapter 7.5.1,
"Command/Response", there is a minimum 8 clock cycles (Ncr) before
the card response shows up on the data out line. However current
implementation jumps directly to the sending response state after
all 6 bytes command is received, which is a spec violation.
Add a new state PREP_RESP in the ssi-sd state machine to handle it.
Fixes: 775616c3ae8c ("Partial SD card SPI mode support")
Signed-off-by: Bin Meng <[email protected]>
Reviewed-by: Pragnesh Patel <[email protected]>
Tested-by: Pragnesh Patel <[email protected]>
---
Changes in v2:
- Add a debug printf in the state handling codes
hw/sd/ssi-sd.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/hw/sd/ssi-sd.c b/hw/sd/ssi-sd.c
index 9a75e0095c..043e270066 100644
--- a/hw/sd/ssi-sd.c
+++ b/hw/sd/ssi-sd.c
@@ -36,6 +36,7 @@ do { fprintf(stderr, "ssi_sd: error: " fmt , ##
__VA_ARGS__);} while (0)
typedef enum {
SSI_SD_CMD = 0,
SSI_SD_CMDARG,
+ SSI_SD_PREP_RESP,
SSI_SD_RESPONSE,
SSI_SD_DATA_START,
SSI_SD_DATA_READ,
@@ -163,12 +164,16 @@ static uint32_t ssi_sd_transfer(SSIPeripheral *dev,
uint32_t val)
s->response[1] = status;
DPRINTF("Card status 0x%02x\n", status);
}
- s->mode = SSI_SD_RESPONSE;
+ s->mode = SSI_SD_PREP_RESP;
s->response_pos = 0;
} else {
s->cmdarg[s->arglen++] = val;
}
return 0xff;
+ case SSI_SD_PREP_RESP:
+ DPRINTF("Prepare card response (Ncr)\n");
+ s->mode = SSI_SD_RESPONSE;
+ return 0xff;
case SSI_SD_RESPONSE:
if (s->stopping) {
s->stopping = 0;
--
2.25.1
