mmc: mmc: Add functions to enable / disable the Command Queue

Add helper functions to enable or disable the Command Queue.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Documentation/mmc/mmc-dev-attrs.txt

@@ -30,6 +30,7 @@ All attributes are read-only.
 	rel_sectors		Reliable write sector count
 	ocr 			Operation Conditions Register
 	dsr			Driver Stage Register
+	cmdq_en			Command Queue enabled: 1 => enabled, 0 => not enabled
 
 Note on Erase Size and Preferred Erase Size:
 

drivers/mmc/core/mmc.c

@@ -790,6 +790,7 @@ MMC_DEV_ATTR(enhanced_area_size, "%u\n", card->ext_csd.enhanced_area_size);
 MMC_DEV_ATTR(raw_rpmb_size_mult, "%#x\n", card->ext_csd.raw_rpmb_size_mult);
 MMC_DEV_ATTR(rel_sectors, "%#x\n", card->ext_csd.rel_sectors);
 MMC_DEV_ATTR(ocr, "%08x\n", card->ocr);
+MMC_DEV_ATTR(cmdq_en, "%d\n", card->ext_csd.cmdq_en);
 
 static ssize_t mmc_fwrev_show(struct device *dev,
 			      struct device_attribute *attr,
@@ -845,6 +846,7 @@ static struct attribute *mmc_std_attrs[] = {
 	&dev_attr_rel_sectors.attr,
 	&dev_attr_ocr.attr,
 	&dev_attr_dsr.attr,
+	&dev_attr_cmdq_en.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(mmc_std);

drivers/mmc/core/mmc_ops.c

@@ -838,3 +838,31 @@ int mmc_can_ext_csd(struct mmc_card *card)
 {
 	return (card && card->csd.mmca_vsn > CSD_SPEC_VER_3);
 }
+
+static int mmc_cmdq_switch(struct mmc_card *card, bool enable)
+{
+	u8 val = enable ? EXT_CSD_CMDQ_MODE_ENABLED : 0;
+	int err;
+
+	if (!card->ext_csd.cmdq_support)
+		return -EOPNOTSUPP;
+
+	err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_CMDQ_MODE_EN,
+			 val, 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, true);
+}
+EXPORT_SYMBOL_GPL(mmc_cmdq_enable);
+
+int mmc_cmdq_disable(struct mmc_card *card)
+{
+	return mmc_cmdq_switch(card, false);
+}
+EXPORT_SYMBOL_GPL(mmc_cmdq_disable);

drivers/mmc/core/mmc_ops.h

@@ -46,6 +46,8 @@ int mmc_read_bkops_status(struct mmc_card *card);
 void mmc_start_bkops(struct mmc_card *card, bool from_exception);
 int mmc_can_reset(struct mmc_card *card);
 int mmc_flush_cache(struct mmc_card *card);
+int mmc_cmdq_enable(struct mmc_card *card);
+int mmc_cmdq_disable(struct mmc_card *card);
 
 #endif
 

include/linux/mmc/card.h

@@ -89,6 +89,7 @@ struct mmc_ext_csd {
 	unsigned int		boot_ro_lock;		/* ro lock support */
 	bool			boot_ro_lockable;
 	bool			ffu_capable;	/* Firmware upgrade support */
+	bool			cmdq_en;	/* Command Queue enabled */
 	bool			cmdq_support;	/* Command Queue supported */
 	unsigned int		cmdq_depth;	/* Command Queue depth */
 #define MMC_FIRMWARE_LEN 8