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arm:use the 4 bit mmc data bus if supported by the card.

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Change-Id: I55de05db23ad1766e5faec93252e8410cbf59001
This commit is contained in:
Kees Jongenburger 2013-06-21 15:52:52 +02:00
parent b07222a5cd
commit 964e313c94
1 changed files with 84 additions and 0 deletions
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84
drivers/mmc/mmchost_mmchs.c
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@ -810,6 +810,75 @@ select_card(struct sd_card_regs *card)
} }
return 0; return 0;
} }
int
card_scr(struct sd_card_regs *card)
{
uint8_t buffer[8]; /* 64 bits */
uint8_t *p;
int c;
/* the SD CARD configuration register. This is an additional register
* next to the Card Specific register containing additional data we
* need */
struct mmc_command command;
log_trace(&log, "Read card scr\n");
/* send_csd -> r2 response */
command.cmd = SD_APP_SEND_SCR;
command.resp_type = RESP_LEN_48;
command.args = 0xaaaaaaaa;
command.data = buffer;
command.data_len = 8;
if (mmc_send_app_cmd(card, &command)) {
return 1;
}
p = (uint8_t *) card->scr;
/* hussle */
for (c = 7; c >= 0; c--) {
*p++ = buffer[c];
}
if (!SCR_SD_BUS_WIDTHS(card->scr) & SCR_SD_BUS_WIDTHS_4BIT) {
/* it would be very weird not to support 4 bits access */
log_warn(&log, "4 bit access not supported\n");
}
log_trace(&log, "1 bit bus width %ssupported\n",
(SCR_SD_BUS_WIDTHS(card->scr) & SCR_SD_BUS_WIDTHS_1BIT) ? "" :
"un");
log_trace(&log, "4 bit bus width %ssupported\n",
(SCR_SD_BUS_WIDTHS(card->scr) & SCR_SD_BUS_WIDTHS_4BIT) ? "" :
"un");
return 0;
}
int
enable_4bit_mode(struct sd_card_regs *card)
{
struct mmc_command command;
if (SCR_SD_BUS_WIDTHS(card->scr) & SCR_SD_BUS_WIDTHS_4BIT) {
/* set transfer width */
command.cmd = SD_APP_SET_BUS_WIDTH;
command.resp_type = RESP_LEN_48;
command.args = 2; /* 4 bits */
if (mmc_send_app_cmd(card, &command)) {
log_warn(&log,
"SD-card does not support 4 bit transfer\n");
return 1;
}
/* now configure the controller to use 4 bit access */
set32(base_address + MMCHS_SD_HCTL, MMCHS_SD_HCTL_DTW,
MMCHS_SD_HCTL_DTW_4BIT);
}
return 0;
}
int int
read_single_block(struct sd_card_regs *card, read_single_block(struct sd_card_regs *card,
uint32_t blknr, unsigned char *buf) uint32_t blknr, unsigned char *buf)
@ -929,6 +998,17 @@ mmchs_card_initialize(struct sd_slot *slot)
return NULL; return NULL;
} }
if (card_scr(&slot->card.regs)) {
log_warn(&log,
"failed to read scr (card additional specific data)\n");
return NULL;
}
if (enable_4bit_mode(&slot->card.regs)) {
log_warn(&log, "failed to configure 4 bit access mode\n");
return NULL;
}
if (SD_CSD_READ_BL_LEN(slot->card.regs.csd) != 0x09) { if (SD_CSD_READ_BL_LEN(slot->card.regs.csd) != 0x09) {
/* for CSD version 2.0 the value is fixed to 0x09 and means a /* for CSD version 2.0 the value is fixed to 0x09 and means a
* block size of 512 */ * block size of 512 */
@ -986,6 +1066,10 @@ mmchs_card_release(struct sd_card *card)
card->state = SD_MODE_UNINITIALIZED; card->state = SD_MODE_UNINITIALIZED;
/* TODO:Set card state */ /* TODO:Set card state */
/* now configure the controller to use 4 bit access */
set32(base_address + MMCHS_SD_HCTL, MMCHS_SD_HCTL_DTW,
MMCHS_SD_HCTL_DTW_1BIT);
return OK; return OK;
} }