[PATCH 4/5] mmc: sdhci: add quirk for max_discard calculation

[Georgi Djakov <gdjakov@mm-sol.com>]

The SDHCI driver by default specifies a parameter that causes the core
layer to calculate a max discard value which will be set on the mmc queue.
Unfortunately the value calculated because of this would be very small
compared to what comes in by default. As a result of this, any secure
discard kind of operations are very slow.

Add quirk so that the SDHCI host can use the default max_discard value.

CC: Krishna Konda <kkonda@codeaurora.org>
Signed-off-by: Georgi Djakov <gdjakov@mm-sol.com>
---
 drivers/mmc/host/sdhci.c  |    3 ++-
 include/linux/mmc/sdhci.h |    4 ++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 39544b4..e21bb6f 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2957,7 +2957,8 @@ int sdhci_add_host(struct sdhci_host *host)
 	if (host->quirks & SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK)
 		host->timeout_clk = mmc->f_max / 1000;
 
-	mmc->max_discard_to = (1 << 27) / host->timeout_clk;
+	if (!(host->quirks2 & SDHCI_QUIRK2_USE_MAX_DISCARD_SIZE))
+		mmc->max_discard_to = (1 << 27) / host->timeout_clk;
 
 	mmc->caps |= MMC_CAP_SDIO_IRQ | MMC_CAP_ERASE | MMC_CAP_CMD23;
 
diff --git a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h
index 603ef9d..f42f6dd 100644
--- a/include/linux/mmc/sdhci.h
+++ b/include/linux/mmc/sdhci.h
@@ -104,6 +104,10 @@ struct sdhci_host {
 #define SDHCI_QUIRK2_SLOW_INT_CLR			(1<<7)
 /* Ignore CMD CRC errors for tuning commands */
 #define SDHCI_QUIRK2_IGNORE_CMDCRC_FOR_TUNING		(1<<8)
+/* Dont use the max_discard_to so that the maximum discard unit gets picked by
+ * the mmc queue. Otherwise, it takes a long time for secure discard kind of
+ * operations to complete. */
+#define SDHCI_QUIRK2_USE_MAX_DISCARD_SIZE		(1<<9)
 
 	int irq;		/* Device IRQ */
 	void __iomem *ioaddr;	/* Mapped address */
-- 
1.7.9.5