[PATCH 13/19] mmc: mmci: send stop cmd if a data command fail

[Ludovic Barre]

From: Ludovic Barre <ludovic.barre@xxxxxx>

The mmc framework follows the requirement of SD_Specification:
the STOP_TRANSMISSION is sent on multiple write/read commands
and the stop command (alone), not needed on other ADTC commands.

But, some variants require a stop command "STOP_TRANSMISION" to clear
the DPSM "Data Path State Machine" if an error happens on command or data
step. If it's not done the next data command will freeze hardware block.
Needed to support the STM32 sdmmc variant.

Signed-off-by: Ludovic Barre <ludovic.barre@xxxxxx>
---
 drivers/mmc/host/mmci.c | 36 +++++++++++++++++++++++++++++++-----
 drivers/mmc/host/mmci.h |  3 +++
 2 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 87724e1..9af7db8 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -24,6 +24,7 @@
 #include <linux/mmc/pm.h>
 #include <linux/mmc/host.h>
 #include <linux/mmc/card.h>
+#include <linux/mmc/mmc.h>
 #include <linux/mmc/slot-gpio.h>
 #include <linux/amba/bus.h>
 #include <linux/clk.h>
@@ -522,11 +523,28 @@ static void mmci_set_mask1(struct mmci_host *host, unsigned int mask)
 	host->mask1_reg = mask;
 }
 
-static void mmci_stop_data(struct mmci_host *host)
+static int mmci_stop_data(struct mmci_host *host)
 {
+	struct mmc_command *stop = &host->stop_abort;
+	struct mmc_data *data = host->data;
+	unsigned int cmd = 0;
+
 	mmci_write_datactrlreg(host, 0);
 	mmci_set_mask1(host, 0);
 	host->data = NULL;
+
+	if (host->variant->cmdreg_stop) {
+		cmd |= host->variant->cmdreg_stop;
+		if (!data->stop) {
+			memset(stop, 0, sizeof(struct mmc_command));
+			stop->opcode = MMC_STOP_TRANSMISSION;
+			stop->arg = 0;
+			stop->flags = MMC_RSP_R1B | MMC_CMD_AC;
+			data->stop = stop;
+		}
+	}
+
+	return cmd;
 }
 
 static void mmci_init_sg(struct mmci_host *host, struct mmc_data *data)
@@ -703,6 +721,7 @@ mmci_data_irq(struct mmci_host *host, struct mmc_data *data,
 	      unsigned int status)
 {
 	unsigned int status_err;
+	unsigned int cmd_reg = 0;
 
 	/* Make sure we have data to handle */
 	if (!data)
@@ -761,7 +780,7 @@ mmci_data_irq(struct mmci_host *host, struct mmc_data *data,
 	if (status & MCI_DATAEND || data->error) {
 		mmci_dma_finalize(host, data);
 
-		mmci_stop_data(host);
+		cmd_reg = mmci_stop_data(host);
 
 		if (!data->error)
 			/* The error clause is handled above, success! */
@@ -770,7 +789,7 @@ mmci_data_irq(struct mmci_host *host, struct mmc_data *data,
 		if (!data->stop || host->mrq->sbc) {
 			mmci_request_end(host, data->mrq);
 		} else {
-			mmci_start_command(host, data->stop, 0);
+			mmci_start_command(host, data->stop, cmd_reg);
 		}
 	}
 }
@@ -780,6 +799,8 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd,
 	     unsigned int status)
 {
 	void __iomem *base = host->base;
+	struct mmc_data *data = host->data;
+	unsigned int cmd_reg = 0;
 	bool sbc;
 
 	if (!cmd)
@@ -865,11 +886,16 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd,
 	}
 
 	if ((!sbc && !cmd->data) || cmd->error) {
-		if (host->data) {
+		if (data) {
 			/* Terminate the DMA transfer */
 			mmci_dma_error(host);
 
-			mmci_stop_data(host);
+			cmd_reg = mmci_stop_data(host);
+
+			if (data->stop) {
+				mmci_start_command(host, data->stop, cmd_reg);
+				return;
+			}
 		}
 		mmci_request_end(host, host->mrq);
 	} else if (sbc) {
diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
index 2d7e901..4b4cd1d 100644
--- a/drivers/mmc/host/mmci.h
+++ b/drivers/mmc/host/mmci.h
@@ -243,6 +243,7 @@ struct mmci_host;
  * @cmdreg_lrsp_crc: enable value for long response with crc
  * @cmdreg_srsp_crc: enable value for short response with crc
  * @cmdreg_srsp: enable value for short response without crc
+ * @cmdreg_stop: enable value for stop and abort transmission
  * @datalength_bits: number of bits in the MMCIDATALENGTH register
  * @fifosize: number of bytes that can be written when MMCI_TXFIFOEMPTY
  *	      is asserted (likewise for RX)
@@ -298,6 +299,7 @@ struct variant_data {
 	unsigned int		cmdreg_lrsp_crc;
 	unsigned int		cmdreg_srsp_crc;
 	unsigned int		cmdreg_srsp;
+	unsigned int		cmdreg_stop;
 	unsigned int		datalength_bits;
 	unsigned int		fifosize;
 	unsigned int		fifohalfsize;
@@ -343,6 +345,7 @@ struct mmci_host {
 	struct mmc_request	*mrq;
 	struct mmc_command	*cmd;
 	struct mmc_data		*data;
+	struct mmc_command	stop_abort;
 	struct mmc_host		*mmc;
 	struct clk		*clk;
 	bool			singleirq;
-- 
2.7.4