[PATCH v3 01/12] mmc: sdhci: add support for auto CMD23

[Arindam Nath <arindam.nath@amd.com>]

Host Controller v3.00 and later support Auto CMD23 in the Transfer
Mode register. Since Auto CMD23 can be used with or without DMA,
and if used with DMA, it should _only_ be ADMA, we check against
SDHCI_USE_SDMA not being set. This flag is reset when SDHCI_USE_ADMA
is set.

A new definition for SDHCI_ARGUMENT2 register has been added in v3.00
spec, which is the same as SDHCI_DMA_ADDRESS. We program the block
count for CMD23 in SDHCI_ARGUMENT2, so we don't need CMD12 to stop
multiple block transfers. But during error recovery procedure, we will
need to send Abort command, so we use a variable saved_abort_cmd to
save the stop command to be used later.

Signed-off-by: Arindam Nath <arindam.nath@amd.com>
---
 drivers/mmc/core/sd.c     |    6 ++++
 drivers/mmc/host/sdhci.c  |   71 +++++++++++++++++++++++++++++++++++++++++---
 drivers/mmc/host/sdhci.h  |    2 +
 include/linux/mmc/card.h  |    4 ++
 include/linux/mmc/sd.h    |    2 +-
 include/linux/mmc/sdhci.h |    2 +
 6 files changed, 81 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 6dac89f..460ec24 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -189,6 +189,12 @@ static int mmc_decode_scr(struct mmc_card *card)
 
 	scr->sda_vsn = UNSTUFF_BITS(resp, 56, 4);
 	scr->bus_widths = UNSTUFF_BITS(resp, 48, 4);
+	if (scr->sda_vsn == SCR_SPEC_VER_2) {
+		/* Check if Physical Layer Spec v3.0 is supported*/
+		scr->sda_spec3 = UNSTUFF_BITS(resp, 47, 1);
+		if (scr->sda_spec3)
+			scr->cmd_support = UNSTUFF_BITS(resp, 32, 2);
+	}
 
 	if (UNSTUFF_BITS(resp, 55, 1))
 		card->erased_byte = 0xFF;
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 94793f2..7921ced 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -25,6 +25,7 @@
 
 #include <linux/mmc/mmc.h>
 #include <linux/mmc/host.h>
+#include <linux/mmc/card.h>
 
 #include "sdhci.h"
 
@@ -821,6 +822,30 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd)
 	sdhci_writew(host, data->blocks, SDHCI_BLOCK_COUNT);
 }
 
+/*
+ * Does the Host Controller support Auto CMD23?
+ *
+ * There are four preconditions for Auto CMD23 to be supported:
+ *  1. Host Controller v3.00 or later
+ *  2. Card supports CMD23
+ *  3. If DMA is used, it should be ADMA
+ *  4. Only when CMD18 or CMD25 is issued
+ */
+static int sdhci_host_auto_cmd23_required(struct sdhci_host *host,
+	struct mmc_request *mrq)
+{
+	struct mmc_card *card = host->mmc->card;
+
+	if ((host->version >= SDHCI_SPEC_300) &&
+	   card && (card->scr.cmd_support & SD_SCR_CMD23_SUPPORT) &&
+	   !(host->flags & SDHCI_USE_SDMA) &&
+	   ((mrq->cmd->opcode == MMC_READ_MULTIPLE_BLOCK) ||
+	   (mrq->cmd->opcode == MMC_WRITE_MULTIPLE_BLOCK)))
+		return 1;
+
+	return 0;
+}
+
 static void sdhci_set_transfer_mode(struct sdhci_host *host,
 	struct mmc_data *data)
 {
@@ -834,10 +859,21 @@ static void sdhci_set_transfer_mode(struct sdhci_host *host,
 	mode = SDHCI_TRNS_BLK_CNT_EN;
 	if (data->blocks > 1) {
 		if (host->quirks & SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12)
-			mode |= SDHCI_TRNS_MULTI | SDHCI_TRNS_ACMD12;
-		else
-			mode |= SDHCI_TRNS_MULTI;
+			mode |= SDHCI_TRNS_ACMD12;
+		else if (sdhci_host_auto_cmd23_required(host, host->mrq)) {
+			/*
+			 * Host Controller v3.00 can automatically send CMD23
+			 * before CMD18 or CMD25. For that, we need to enable
+			 * Auto CMD23 in the Transfer Mode register and
+			 * program the block count in Argument 2 register.
+			 */
+			mode |= SDHCI_TRNS_AUTO_CMD23;
+			sdhci_writel(host, data->blocks, SDHCI_ARGUMENT2);
+		}
+
+		mode |= SDHCI_TRNS_MULTI;
 	}
+
 	if (data->flags & MMC_DATA_READ)
 		mode |= SDHCI_TRNS_READ;
 	if (host->flags & SDHCI_REQ_USE_DMA)
@@ -1140,6 +1176,23 @@ static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
 #ifndef SDHCI_USE_LEDS_CLASS
 	sdhci_activate_led(host);
 #endif
+	/*
+	 * Since the block count for CMD23 has already been specified in the
+	 * Argument 2 register, we don't need CMD12 to stop multiple block
+	 * transfers.
+	 */
+	if (sdhci_host_auto_cmd23_required(host, mrq)) {
+		if (mrq->stop) {
+			/*
+			 * Save the stop command here to be used during
+			 * error recovery
+			 */
+			host->saved_abort_cmd = mrq->data->stop;
+			mrq->data->stop = NULL;
+			mrq->stop = NULL;
+		}
+	}
+
 	if (host->quirks & SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12) {
 		if (mrq->stop) {
 			mrq->data->stop = NULL;
@@ -1405,6 +1458,8 @@ static void sdhci_timeout_timer(unsigned long data)
 
 		if (host->data) {
 			host->data->error = -ETIMEDOUT;
+			if (host->saved_abort_cmd)
+				host->data->stop = host->saved_abort_cmd;
 			sdhci_finish_data(host);
 		} else {
 			if (host->cmd)
@@ -1543,9 +1598,11 @@ static void sdhci_data_irq(struct sdhci_host *host, u32 intmask)
 		host->data->error = -EIO;
 	}
 
-	if (host->data->error)
+	if (host->data->error) {
+		if (host->saved_abort_cmd)
+			host->data->stop = host->saved_abort_cmd;
 		sdhci_finish_data(host);
-	else {
+	} else {
 		if (intmask & (SDHCI_INT_DATA_AVAIL | SDHCI_INT_SPACE_AVAIL))
 			sdhci_transfer_pio(host);
 
@@ -1819,6 +1876,10 @@ int sdhci_add_host(struct sdhci_host *host)
 		host->flags &= ~SDHCI_USE_ADMA;
 	}
 
+	/* If the host can perform ADMA operation, we reset SDMA flag */
+	if (host->flags & SDHCI_USE_ADMA)
+		host->flags &= ~SDHCI_USE_SDMA;
+
 	if (host->flags & (SDHCI_USE_SDMA | SDHCI_USE_ADMA)) {
 		if (host->ops->enable_dma) {
 			if (host->ops->enable_dma(host)) {
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 85750a9..9f8575e 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -25,6 +25,7 @@
  */
 
 #define SDHCI_DMA_ADDRESS	0x00
+#define SDHCI_ARGUMENT2		SDHCI_DMA_ADDRESS
 
 #define SDHCI_BLOCK_SIZE	0x04
 #define  SDHCI_MAKE_BLKSZ(dma, blksz) (((dma & 0x7) << 12) | (blksz & 0xFFF))
@@ -37,6 +38,7 @@
 #define  SDHCI_TRNS_DMA		0x01
 #define  SDHCI_TRNS_BLK_CNT_EN	0x02
 #define  SDHCI_TRNS_ACMD12	0x04
+#define  SDHCI_TRNS_AUTO_CMD23	0x08
 #define  SDHCI_TRNS_READ	0x10
 #define  SDHCI_TRNS_MULTI	0x20
 
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 72a9868..86d9672 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -67,9 +67,13 @@ struct mmc_ext_csd {
 
 struct sd_scr {
 	unsigned char		sda_vsn;
+	unsigned char		sda_spec3;
 	unsigned char		bus_widths;
 #define SD_SCR_BUS_WIDTH_1	(1<<0)
 #define SD_SCR_BUS_WIDTH_4	(1<<2)
+	unsigned char		cmd_support;
+#define SD_SCR_CMD20_SUPPORT	(1<<0)
+#define SD_SCR_CMD23_SUPPORT	(1<<1)
 };
 
 struct sd_ssr {
diff --git a/include/linux/mmc/sd.h b/include/linux/mmc/sd.h
index 3fd85e0..178363b 100644
--- a/include/linux/mmc/sd.h
+++ b/include/linux/mmc/sd.h
@@ -59,7 +59,7 @@
 
 #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 */
+#define SCR_SPEC_VER_2		2	/* Implements system specification 2.00 - 3.0x */
 
 /*
  * SD bus widths
diff --git a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h
index 83bd9f7..282d158 100644
--- a/include/linux/mmc/sdhci.h
+++ b/include/linux/mmc/sdhci.h
@@ -145,6 +145,8 @@ struct sdhci_host {
 	unsigned int            ocr_avail_sd;
 	unsigned int            ocr_avail_mmc;
 
+	struct mmc_command	*saved_abort_cmd; /* Abort command saved for data error recovery */
+
 	unsigned long private[0] ____cacheline_aligned;
 };
 #endif /* __SDHCI_H */
-- 
1.7.1