mmc: sdhci: track whether preset mode is currently enabled in hardware

Track whether preset mode is currently enabled in hardware, and use that
when making decisions elsewhere in the code rather than reading the
register and checking the bit.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Markus Pargmann <mpa@pengutronix.de>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>

drivers/mmc/host/sdhci.c

@@ -205,10 +205,15 @@ static void sdhci_do_reset(struct sdhci_host *host, u8 mask)
 
 	host->ops->reset(host, mask);
 
+	if (mask & SDHCI_RESET_ALL) {
 		if (host->flags & (SDHCI_USE_SDMA | SDHCI_USE_ADMA)) {
-		if ((host->ops->enable_dma) && (mask & SDHCI_RESET_ALL))
+			if (host->ops->enable_dma)
 				host->ops->enable_dma(host);
 		}
+
+		/* Resetting the controller clears many */
+		host->preset_enabled = false;
+	}
 }
 
 static void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios);
@@ -1126,8 +1131,7 @@ void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
 		return;
 
 	if (host->version >= SDHCI_SPEC_300) {
-		if (sdhci_readw(host, SDHCI_HOST_CONTROL2) &
-			SDHCI_CTRL_PRESET_VAL_ENABLE) {
+		if (host->preset_enabled) {
 			u16 pre_val;
 
 			clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
@@ -1493,13 +1497,13 @@ static void sdhci_do_set_ios(struct sdhci_host *host, struct mmc_ios *ios)
 		    (ios->timing == MMC_TIMING_UHS_SDR25))
 			ctrl |= SDHCI_CTRL_HISPD;
 
-		ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
-		if (!(ctrl_2 & SDHCI_CTRL_PRESET_VAL_ENABLE)) {
+		if (!host->preset_enabled) {
 			sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
 			/*
 			 * We only need to set Driver Strength if the
 			 * preset value enable is not set.
 			 */
+			ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
 			ctrl_2 &= ~SDHCI_CTRL_DRV_TYPE_MASK;
 			if (ios->drv_type == MMC_SET_DRIVER_TYPE_A)
 				ctrl_2 |= SDHCI_CTRL_DRV_TYPE_A;
@@ -2018,26 +2022,30 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
 
 static void sdhci_enable_preset_value(struct sdhci_host *host, bool enable)
 {
-	u16 ctrl;
-
 	/* Host Controller v3.00 defines preset value registers */
 	if (host->version < SDHCI_SPEC_300)
 		return;
 
-	ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
-
 	/*
 	 * We only enable or disable Preset Value if they are not already
 	 * enabled or disabled respectively. Otherwise, we bail out.
 	 */
-	if (enable && !(ctrl & SDHCI_CTRL_PRESET_VAL_ENABLE)) {
+	if (host->preset_enabled != enable) {
+		u16 ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+
+		if (enable)
 			ctrl |= SDHCI_CTRL_PRESET_VAL_ENABLE;
-		sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
-		host->flags |= SDHCI_PV_ENABLED;
-	} else if (!enable && (ctrl & SDHCI_CTRL_PRESET_VAL_ENABLE)) {
+		else
 			ctrl &= ~SDHCI_CTRL_PRESET_VAL_ENABLE;
+
 		sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
+
+		if (enable)
+			host->flags |= SDHCI_PV_ENABLED;
+		else
 			host->flags &= ~SDHCI_PV_ENABLED;
+
+		host->preset_enabled = enable;
 	}
 }
 

include/linux/mmc/sdhci.h

@@ -143,6 +143,7 @@ struct sdhci_host {
 
 	bool runtime_suspended;	/* Host is runtime suspended */
 	bool bus_on;		/* Bus power prevents runtime suspend */
+	bool preset_enabled;	/* Preset is enabled */
 
 	struct mmc_request *mrq;	/* Current request */
 	struct mmc_command *cmd;	/* Current command */