mmc: mmci: add variant property to set command stop bit

On cmd12 (STOP_TRANSMISSION), STM32 sdmmc variant needs to set
cmdstop bit in command register. The CPSM ("Command Path State Machine")
treats the command as a Stop Transmission command and signals
abort to the DPSM ("Data Path State Machine").
Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/mmci.c

@@ -21,6 +21,7 @@
 #include <linux/err.h>
 #include <linux/highmem.h>
 #include <linux/log2.h>
+#include <linux/mmc/mmc.h>
 #include <linux/mmc/pm.h>
 #include <linux/mmc/host.h>
 #include <linux/mmc/card.h>
@@ -274,6 +275,7 @@ static struct variant_data variant_stm32_sdmmc = {
 	.cmdreg_lrsp_crc	= MCI_CPSM_STM32_LRSP_CRC,
 	.cmdreg_srsp_crc	= MCI_CPSM_STM32_SRSP_CRC,
 	.cmdreg_srsp		= MCI_CPSM_STM32_SRSP,
+	.cmdreg_stop		= MCI_CPSM_STM32_CMDSTOP,
 	.data_cmd_enable	= MCI_CPSM_STM32_CMDTRANS,
 	.irq_pio_mask		= MCI_IRQ_PIO_STM32_MASK,
 	.datactrl_first		= true,
@@ -1100,6 +1102,10 @@ mmci_start_command(struct mmci_host *host, struct mmc_command *cmd, u32 c)
 		mmci_reg_delay(host);
 	}
 
+	if (host->variant->cmdreg_stop &&
+	    cmd->opcode == MMC_STOP_TRANSMISSION)
+		c |= host->variant->cmdreg_stop;
+
 	c |= cmd->opcode | host->variant->cmdreg_cpsm_enable;
 	if (cmd->flags & MMC_RSP_PRESENT) {
 		if (cmd->flags & MMC_RSP_136)

drivers/mmc/host/mmci.h

@@ -264,6 +264,7 @@ 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)
@@ -316,6 +317,7 @@ 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;