mmc: sdhci: introduce get_ro private write-protect hook

Some controllers handle their write-protection differently. Introduce a
callback to be able to handle it, ensuring the same locking takes place
for it. Rename the status variable to make it more obvious why the read
from the registers needs to be inverted.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Tested-by: Eric Bénard <eric@eukrea.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/host/sdhci.c

@@ -1223,22 +1223,25 @@ static int sdhci_get_ro(struct mmc_host *mmc)
 {
 	struct sdhci_host *host;
 	unsigned long flags;
-	int present;
+	int is_readonly;
 
 	host = mmc_priv(mmc);
 
 	spin_lock_irqsave(&host->lock, flags);
 
 	if (host->flags & SDHCI_DEVICE_DEAD)
-		present = 0;
+		is_readonly = 0;
+	else if (host->ops->get_ro)
+		is_readonly = host->ops->get_ro(host);
 	else
-		present = sdhci_readl(host, SDHCI_PRESENT_STATE);
+		is_readonly = !(sdhci_readl(host, SDHCI_PRESENT_STATE)
+				& SDHCI_WRITE_PROTECT);
 
 	spin_unlock_irqrestore(&host->lock, flags);
 
-	if (host->quirks & SDHCI_QUIRK_INVERTED_WRITE_PROTECT)
-		return !!(present & SDHCI_WRITE_PROTECT);
-	return !(present & SDHCI_WRITE_PROTECT);
+	/* This quirk needs to be replaced by a callback-function later */
+	return host->quirks & SDHCI_QUIRK_INVERTED_WRITE_PROTECT ?
+		!is_readonly : is_readonly;
 }
 
 static void sdhci_enable_sdio_irq(struct mmc_host *mmc, int enable)

drivers/mmc/host/sdhci.h

@@ -214,6 +214,7 @@ struct sdhci_ops {
 	unsigned int	(*get_timeout_clock)(struct sdhci_host *host);
 	void (*platform_send_init_74_clocks)(struct sdhci_host *host,
 					     u8 power_mode);
+	unsigned int    (*get_ro)(struct sdhci_host *host);
 };
 
 #ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS