mmc: Support for high speed SD cards
Modern SD cards support a clock speed of 50 MHz. Make sure we test for
this capability and do the song and dance required to activate it.
Activating high speed support actually modifies the TRAN_SPEED field
of the CSD. But as the spec says that the cards must report 50 MHz,
we might as well skip re-reading the CSD.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 82b7643..9d19002 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -1157,6 +1157,116 @@
mmc_deselect_cards(host);
}
+static void mmc_read_switch_caps(struct mmc_host *host)
+{
+ int err;
+ struct mmc_card *card;
+ struct mmc_request mrq;
+ struct mmc_command cmd;
+ struct mmc_data data;
+ unsigned char *status;
+ struct scatterlist sg;
+
+ status = kmalloc(64, GFP_KERNEL);
+ if (!status) {
+ printk(KERN_WARNING "%s: Unable to allocate buffer for "
+ "reading switch capabilities.\n",
+ mmc_hostname(host));
+ return;
+ }
+
+ list_for_each_entry(card, &host->cards, node) {
+ if (card->state & (MMC_STATE_DEAD|MMC_STATE_PRESENT))
+ continue;
+ if (!mmc_card_sd(card))
+ continue;
+ if (card->scr.sda_vsn < SCR_SPEC_VER_1)
+ continue;
+
+ err = mmc_select_card(host, card);
+ if (err != MMC_ERR_NONE) {
+ mmc_card_set_dead(card);
+ continue;
+ }
+
+ memset(&cmd, 0, sizeof(struct mmc_command));
+
+ cmd.opcode = SD_SWITCH;
+ cmd.arg = 0x00FFFFF1;
+ cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
+
+ memset(&data, 0, sizeof(struct mmc_data));
+
+ mmc_set_data_timeout(&data, card, 0);
+
+ data.blksz = 64;
+ data.blocks = 1;
+ data.flags = MMC_DATA_READ;
+ data.sg = &sg;
+ data.sg_len = 1;
+
+ memset(&mrq, 0, sizeof(struct mmc_request));
+
+ mrq.cmd = &cmd;
+ mrq.data = &data;
+
+ sg_init_one(&sg, status, 64);
+
+ mmc_wait_for_req(host, &mrq);
+
+ if (cmd.error != MMC_ERR_NONE || data.error != MMC_ERR_NONE) {
+ mmc_card_set_dead(card);
+ continue;
+ }
+
+ if (status[13] & 0x02)
+ card->sw_caps.hs_max_dtr = 50000000;
+
+ memset(&cmd, 0, sizeof(struct mmc_command));
+
+ cmd.opcode = SD_SWITCH;
+ cmd.arg = 0x80FFFFF1;
+ cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
+
+ memset(&data, 0, sizeof(struct mmc_data));
+
+ mmc_set_data_timeout(&data, card, 0);
+
+ data.blksz = 64;
+ data.blocks = 1;
+ data.flags = MMC_DATA_READ;
+ data.sg = &sg;
+ data.sg_len = 1;
+
+ memset(&mrq, 0, sizeof(struct mmc_request));
+
+ mrq.cmd = &cmd;
+ mrq.data = &data;
+
+ sg_init_one(&sg, status, 64);
+
+ mmc_wait_for_req(host, &mrq);
+
+ if (cmd.error != MMC_ERR_NONE || data.error != MMC_ERR_NONE) {
+ mmc_card_set_dead(card);
+ continue;
+ }
+
+ if ((status[16] & 0xF) != 1) {
+ printk(KERN_WARNING "%s: Problem switching card "
+ "into high-speed mode!\n",
+ mmc_hostname(host));
+ continue;
+ }
+
+ mmc_card_set_highspeed(card);
+ }
+
+ kfree(status);
+
+ mmc_deselect_cards(host);
+}
+
static unsigned int mmc_calculate_clock(struct mmc_host *host)
{
struct mmc_card *card;
@@ -1164,9 +1274,12 @@
list_for_each_entry(card, &host->cards, node)
if (!mmc_card_dead(card)) {
- if (mmc_card_highspeed(card)) {
+ if (mmc_card_highspeed(card) && mmc_card_sd(card)) {
+ if (max_dtr > card->sw_caps.hs_max_dtr)
+ max_dtr = card->sw_caps.hs_max_dtr;
+ } else if (mmc_card_highspeed(card) && !mmc_card_sd(card)) {
if (max_dtr > card->ext_csd.hs_max_dtr)
- max_dtr = card->ext_csd.hs_max_dtr;
+ max_dtr = card->ext_csd.hs_max_dtr;
} else if (max_dtr > card->csd.max_dtr) {
max_dtr = card->csd.max_dtr;
}
@@ -1288,9 +1401,10 @@
mmc_read_csds(host);
- if (host->mode == MMC_MODE_SD)
+ if (host->mode == MMC_MODE_SD) {
mmc_read_scrs(host);
- else
+ mmc_read_switch_caps(host);
+ } else
mmc_process_ext_csds(host);
}
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index ce25256..d0e6a54 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -50,6 +50,10 @@
#define SD_SCR_BUS_WIDTH_4 (1<<2)
};
+struct sd_switch_caps {
+ unsigned int hs_max_dtr;
+};
+
struct mmc_host;
/*
@@ -66,7 +70,7 @@
#define MMC_STATE_BAD (1<<2) /* unrecognised device */
#define MMC_STATE_SDCARD (1<<3) /* is an SD card */
#define MMC_STATE_READONLY (1<<4) /* card is read-only */
-#define MMC_STATE_HIGHSPEED (1<<5) /* card is in mmc4 highspeed mode */
+#define MMC_STATE_HIGHSPEED (1<<5) /* card is in high speed mode */
u32 raw_cid[4]; /* raw card CID */
u32 raw_csd[4]; /* raw card CSD */
u32 raw_scr[2]; /* raw card SCR */
@@ -74,6 +78,7 @@
struct mmc_csd csd; /* card specific */
struct mmc_ext_csd ext_csd; /* mmc v4 extended card specific */
struct sd_scr scr; /* extra SD information */
+ struct sd_switch_caps sw_caps; /* switch (CMD6) caps */
};
#define mmc_card_present(c) ((c)->state & MMC_STATE_PRESENT)
diff --git a/include/linux/mmc/protocol.h b/include/linux/mmc/protocol.h
index 45c51fd8..2dce60c 100644
--- a/include/linux/mmc/protocol.h
+++ b/include/linux/mmc/protocol.h
@@ -82,6 +82,7 @@
/* class 8 */
/* This is basically the same command as for MMC with some quirks. */
#define SD_SEND_RELATIVE_ADDR 3 /* bcr R6 */
+#define SD_SWITCH 6 /* adtc [31:0] See below R1 */
/* Application commands */
#define SD_APP_SET_BUS_WIDTH 6 /* ac [1:0] bus width R1 */
@@ -101,6 +102,19 @@
*/
/*
+ * SD_SWITCH argument format:
+ *
+ * [31] Check (0) or switch (1)
+ * [30:24] Reserved (0)
+ * [23:20] Function group 6
+ * [19:16] Function group 5
+ * [15:12] Function group 4
+ * [11:8] Function group 3
+ * [7:4] Function group 2
+ * [3:0] Function group 1
+ */
+
+/*
MMC status in R1
Type
e : error bit
@@ -285,6 +299,14 @@
#define MMC_SWITCH_MODE_WRITE_BYTE 0x03 /* Set target to value */
/*
+ * SCR field definitions
+ */
+
+#define SCR_SPEC_VER_0 0 /* Implements system specification 1.0 - 1.01 */
+#define SCR_SPEC_VER_1 1 /* Implements system specification 1.10 */
+#define SCR_SPEC_VER_2 2 /* Implements system specification 2.00 */
+
+/*
* SD bus widths
*/
#define SD_BUS_WIDTH_1 0