mmc: Add support for SDHC cards

Thanks to the generous donation of an SDHC card by John Gilmore, and
the surprisingly enlightened decision by the SD Card Association to
publish useful specs, I've been able to bash out support for SDHC. The
changes are not too profound:

i) Add a card flag indicating the card uses block level addressing and
check it in the block driver. As we never took advantage of byte-level
addressing, this simply involves skipping the block -> byte
translation when sending commands.

ii) The layout of the CSD is changed - a set of fields are discarded
to make space for a larger C_SIZE. We did not reference any of the
discarded fields except those related to the C_SIZE.

iii) Read and write timeouts are fixed values and not calculated from
CSD values.

iv) Before invoking SEND_APP_OP_COND, we must invoke the new
SEND_IF_COND to inform the card we support SDHC.
Signed-off-by: NPhilipl Langdale <philipl@overt.org>
Signed-off-by: NPierre Ossman <drzeus@drzeus.cx>

drivers/mmc/mmc.c

@@ -289,7 +289,10 @@ void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card,
 		else
 			limit_us = 100000;
 
-		if (timeout_us > limit_us) {
+		/*
+		 * SDHC cards always use these fixed values.
+		 */
+		if (timeout_us > limit_us || mmc_card_blockaddr(card)) {
 			data->timeout_ns = limit_us * 1000;
 			data->timeout_clks = 0;
 		}
@@ -588,13 +591,9 @@ static void mmc_decode_csd(struct mmc_card *card)
 
 	if (mmc_card_sd(card)) {
 		csd_struct = UNSTUFF_BITS(resp, 126, 2);
-		if (csd_struct != 0) {
-			printk("%s: unrecognised CSD structure version %d\n",
-				mmc_hostname(card->host), csd_struct);
-			mmc_card_set_bad(card);
-			return;
-		}
 
+		switch (csd_struct) {
+		case 0:
 			m = UNSTUFF_BITS(resp, 115, 4);
 			e = UNSTUFF_BITS(resp, 112, 3);
 			csd->tacc_ns	 = (tacc_exp[e] * tacc_mant[m] + 9) / 10;
@@ -616,6 +615,41 @@ static void mmc_decode_csd(struct mmc_card *card)
 			csd->r2w_factor = UNSTUFF_BITS(resp, 26, 3);
 			csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4);
 			csd->write_partial = UNSTUFF_BITS(resp, 21, 1);
+			break;
+		case 1:
+			/*
+			 * This is a block-addressed SDHC card. Most
+			 * interesting fields are unused and have fixed
+			 * values. To avoid getting tripped by buggy cards,
+			 * we assume those fixed values ourselves.
+			 */
+			mmc_card_set_blockaddr(card);
+
+			csd->tacc_ns	 = 0; /* Unused */
+			csd->tacc_clks	 = 0; /* Unused */
+
+			m = UNSTUFF_BITS(resp, 99, 4);
+			e = UNSTUFF_BITS(resp, 96, 3);
+			csd->max_dtr	  = tran_exp[e] * tran_mant[m];
+			csd->cmdclass	  = UNSTUFF_BITS(resp, 84, 12);
+
+			m = UNSTUFF_BITS(resp, 48, 22);
+			csd->capacity     = (1 + m) << 10;
+
+			csd->read_blkbits = 9;
+			csd->read_partial = 0;
+			csd->write_misalign = 0;
+			csd->read_misalign = 0;
+			csd->r2w_factor = 4; /* Unused */
+			csd->write_blkbits = 9;
+			csd->write_partial = 0;
+			break;
+		default:
+			printk("%s: unrecognised CSD structure version %d\n",
+				mmc_hostname(card->host), csd_struct);
+			mmc_card_set_bad(card);
+			return;
+		}
 	} else {
 		/*
 		 * We only understand CSD structure v1.1 and v1.2.
@@ -848,6 +882,41 @@ static int mmc_send_app_op_cond(struct mmc_host *host, u32 ocr, u32 *rocr)
 	return err;
 }
 
+static int mmc_send_if_cond(struct mmc_host *host, u32 ocr, int *rsd2)
+{
+	struct mmc_command cmd;
+	int err, sd2;
+	static const u8 test_pattern = 0xAA;
+
+	/*
+	* To support SD 2.0 cards, we must always invoke SD_SEND_IF_COND
+	* before SD_APP_OP_COND. This command will harmlessly fail for
+	* SD 1.0 cards.
+	*/
+	cmd.opcode = SD_SEND_IF_COND;
+	cmd.arg = ((ocr & 0xFF8000) != 0) << 8 | test_pattern;
+	cmd.flags = MMC_RSP_R7 | MMC_CMD_BCR;
+
+	err = mmc_wait_for_cmd(host, &cmd, 0);
+	if (err == MMC_ERR_NONE) {
+		if ((cmd.resp[0] & 0xFF) == test_pattern) {
+			sd2 = 1;
+		} else {
+			sd2 = 0;
+			err = MMC_ERR_FAILED;
+		}
+	} else {
+		/*
+		 * Treat errors as SD 1.0 card.
+		 */
+		sd2 = 0;
+		err = MMC_ERR_NONE;
+	}
+	if (rsd2)
+		*rsd2 = sd2;
+	return err;
+}
+
 /*
  * Discover cards by requesting their CID.  If this command
  * times out, it is not an error; there are no further cards
@@ -1334,6 +1403,10 @@ static void mmc_setup(struct mmc_host *host)
 		mmc_power_up(host);
 		mmc_idle_cards(host);
 
+		err = mmc_send_if_cond(host, host->ocr_avail, NULL);
+		if (err != MMC_ERR_NONE) {
+			return;
+		}
 		err = mmc_send_app_op_cond(host, 0, &ocr);
 
 		/*
@@ -1386,10 +1459,21 @@ static void mmc_setup(struct mmc_host *host)
 	 * all get the idea that they should be ready for CMD2.
 	 * (My SanDisk card seems to need this.)
 	 */
-	if (host->mode == MMC_MODE_SD)
-		mmc_send_app_op_cond(host, host->ocr, NULL);
-	else
+	if (host->mode == MMC_MODE_SD) {
+		int err, sd2;
+		err = mmc_send_if_cond(host, host->ocr, &sd2);
+		if (err == MMC_ERR_NONE) {
+			/*
+			* If SD_SEND_IF_COND indicates an SD 2.0
+			* compliant card and we should set bit 30
+			* of the ocr to indicate that we can handle
+			* block-addressed SDHC cards.
+			*/
+			mmc_send_app_op_cond(host, host->ocr | (sd2 << 30), NULL);
+		}
+	} else {
 		mmc_send_op_cond(host, host->ocr, NULL);
+	}
 
 	mmc_discover_cards(host);
 

drivers/mmc/mmc_block.c

@@ -237,7 +237,9 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 		brq.mrq.cmd = &brq.cmd;
 		brq.mrq.data = &brq.data;
 
-		brq.cmd.arg = req->sector << 9;
+		brq.cmd.arg = req->sector;
+		if (!mmc_card_blockaddr(card))
+			brq.cmd.arg <<= 9;
 		brq.cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
 		brq.data.blksz = 1 << md->block_bits;
 		brq.data.blocks = req->nr_sectors >> (md->block_bits - 9);
@@ -494,6 +496,10 @@ mmc_blk_set_blksize(struct mmc_blk_data *md, struct mmc_card *card)
 	struct mmc_command cmd;
 	int err;
 
+	/* Block-addressed cards ignore MMC_SET_BLOCKLEN. */
+	if (mmc_card_blockaddr(card))
+		return 0;
+
 	mmc_card_claim_host(card);
 	cmd.opcode = MMC_SET_BLOCKLEN;
 	cmd.arg = 1 << md->block_bits;

include/linux/mmc/card.h

@@ -71,6 +71,7 @@ struct mmc_card {
 #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 high speed mode */
+#define MMC_STATE_BLOCKADDR	(1<<6)		/* card uses block-addressing */
 	u32			raw_cid[4];	/* raw card CID */
 	u32			raw_csd[4];	/* raw card CSD */
 	u32			raw_scr[2];	/* raw card SCR */
@@ -87,6 +88,7 @@ struct mmc_card {
 #define mmc_card_sd(c)		((c)->state & MMC_STATE_SDCARD)
 #define mmc_card_readonly(c)	((c)->state & MMC_STATE_READONLY)
 #define mmc_card_highspeed(c)	((c)->state & MMC_STATE_HIGHSPEED)
+#define mmc_card_blockaddr(c)	((c)->state & MMC_STATE_BLOCKADDR)
 
 #define mmc_card_set_present(c)	((c)->state |= MMC_STATE_PRESENT)
 #define mmc_card_set_dead(c)	((c)->state |= MMC_STATE_DEAD)
@@ -94,6 +96,7 @@ struct mmc_card {
 #define mmc_card_set_sd(c)	((c)->state |= MMC_STATE_SDCARD)
 #define mmc_card_set_readonly(c) ((c)->state |= MMC_STATE_READONLY)
 #define mmc_card_set_highspeed(c) ((c)->state |= MMC_STATE_HIGHSPEED)
+#define mmc_card_set_blockaddr(c) ((c)->state |= MMC_STATE_BLOCKADDR)
 
 #define mmc_card_name(c)	((c)->cid.prod_name)
 #define mmc_card_id(c)		((c)->dev.bus_id)

include/linux/mmc/mmc.h

@@ -43,6 +43,7 @@ struct mmc_command {
 #define MMC_RSP_R2	(MMC_RSP_PRESENT|MMC_RSP_136|MMC_RSP_CRC)
 #define MMC_RSP_R3	(MMC_RSP_PRESENT)
 #define MMC_RSP_R6	(MMC_RSP_PRESENT|MMC_RSP_CRC|MMC_RSP_OPCODE)
+#define MMC_RSP_R7	(MMC_RSP_PRESENT|MMC_RSP_CRC|MMC_RSP_OPCODE)
 
 #define mmc_resp_type(cmd)	((cmd)->flags & (MMC_RSP_PRESENT|MMC_RSP_136|MMC_RSP_CRC|MMC_RSP_BUSY|MMC_RSP_OPCODE))
 

include/linux/mmc/protocol.h

@@ -79,9 +79,12 @@
 #define MMC_GEN_CMD              56   /* adtc [0] RD/WR          R1  */
 
 /* SD commands                           type  argument     response */
-  /* class 8 */
+  /* class 0 */
 /* This is basically the same command as for MMC with some quirks. */
 #define SD_SEND_RELATIVE_ADDR     3   /* bcr                     R6  */
+#define SD_SEND_IF_COND           8   /* bcr  [11:0] See below   R7  */
+
+  /* class 10 */
 #define SD_SWITCH                 6   /* adtc [31:0] See below   R1  */
 
   /* Application commands */
@@ -114,6 +117,14 @@
  *      [3:0] Function group 1
  */
 
+/*
+ * SD_SEND_IF_COND argument format:
+ *
+ *	[31:12] Reserved (0)
+ *	[11:8] Host Voltage Supply Flags
+ *	[7:0] Check Pattern (0xAA)
+ */
+
 /*
   MMC status in R1
   Type