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hw/sd: ssi-sd: Fix incorrect card response sequence 

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: 775616c3ae ("Partial SD card SPI mode support")
Signed-off-by: Bin Meng <bin.meng@windriver.com>
Tested-by: Pragnesh Patel <pragnesh.patel@sifive.com>
Reviewed-by: Pragnesh Patel <pragnesh.patel@sifive.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20210123104016.17485-4-bmeng.cn@gmail.com>
[PMD: Change VMState version id 2 -> 3]
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
This commit is contained in:
Bin Meng 2021-01-23 18:39:54 +08:00 committed by Philippe Mathieu-Daudé
parent e93c65a6c6
commit 281c5c95b2
1 changed files with 8 additions and 3 deletions
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11
hw/sd/ssi-sd.c
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@ -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;
@ -224,8 +229,8 @@ static int ssi_sd_post_load(void *opaque, int version_id)
static const VMStateDescription vmstate_ssi_sd = {
.name = "ssi_sd",
.version_id = 2,
.minimum_version_id = 2,
.version_id = 3,
.minimum_version_id = 3,
.post_load = ssi_sd_post_load,
.fields = (VMStateField []) {
VMSTATE_UINT32(mode, ssi_sd_state),