[PATCH V4 15/30] mmc: mmc: Add functions to enable / disable the Command Queue

[Adrian Hunter <adrian.hunter@intel.com>]

Add helper functions to enable or disable the Command Queue.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/mmc/core/mmc_ops.c | 27 +++++++++++++++++++++++++++
 include/linux/mmc/core.h   |  2 ++
 2 files changed, 29 insertions(+)

diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index ad6e9798e949..7ec7d62922b0 100644
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -797,3 +797,30 @@ int mmc_can_ext_csd(struct mmc_card *card)
 {
 	return (card && card->csd.mmca_vsn > CSD_SPEC_VER_3);
 }
+
+int mmc_cmdq_switch(struct mmc_card *card, int enable)
+{
+	int err;
+
+	if (!card->ext_csd.cmdq_support)
+		return -EOPNOTSUPP;
+
+	err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_CMDQ_MODE_EN,
+			 enable, card->ext_csd.generic_cmd6_time);
+	if (!err)
+		card->ext_csd.cmdq_en = enable;
+
+	return err;
+}
+
+int mmc_cmdq_enable(struct mmc_card *card)
+{
+	return mmc_cmdq_switch(card, EXT_CSD_CMDQ_MODE_ENABLED);
+}
+EXPORT_SYMBOL_GPL(mmc_cmdq_enable);
+
+int mmc_cmdq_disable(struct mmc_card *card)
+{
+	return mmc_cmdq_switch(card, 0);
+}
+EXPORT_SYMBOL_GPL(mmc_cmdq_disable);
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index 368bed70aa9d..63dc01257852 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -161,6 +161,8 @@ extern void mmc_start_bkops(struct mmc_card *card, bool from_exception);
 extern int mmc_switch(struct mmc_card *, u8, u8, u8, unsigned int);
 extern int mmc_send_tuning(struct mmc_host *host, u32 opcode, int *cmd_error);
 extern int mmc_get_ext_csd(struct mmc_card *card, u8 **new_ext_csd);
+extern int mmc_cmdq_enable(struct mmc_card *card);
+extern int mmc_cmdq_disable(struct mmc_card *card);
 
 #define MMC_ERASE_ARG		0x00000000
 #define MMC_SECURE_ERASE_ARG	0x80000000
-- 
1.9.1