[PATCH v2] mmc: mtk-sd: reduce CIT for better performance

[Wenbin Mei <wenbin.mei@mediatek.com>]

CQHCI_SSC1 indicates to CQE the polling period to use when using periodic
SEND_QUEUE_STATUS(CMD13) polling.
The default value 0x1000 that corresponds to 150us, let's decrease it to
0x40 that corresponds to 3us, which can improve the performance of some
eMMC devices.

Signed-off-by: Wenbin Mei <wenbin.mei@mediatek.com>
---
 drivers/mmc/host/mtk-sd.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
index edade0e54a0c..ffeccddcd028 100644
--- a/drivers/mmc/host/mtk-sd.c
+++ b/drivers/mmc/host/mtk-sd.c
@@ -2453,6 +2453,7 @@ static void msdc_hs400_enhanced_strobe(struct mmc_host *mmc,
 static void msdc_cqe_enable(struct mmc_host *mmc)
 {
 	struct msdc_host *host = mmc_priv(mmc);
+	struct cqhci_host *cq_host = mmc->cqe_private;
 
 	/* enable cmdq irq */
 	writel(MSDC_INT_CMDQ, host->base + MSDC_INTEN);
@@ -2462,6 +2463,9 @@ static void msdc_cqe_enable(struct mmc_host *mmc)
 	msdc_set_busy_timeout(host, 20 * 1000000000ULL, 0);
 	/* default read data timeout 1s */
 	msdc_set_timeout(host, 1000000000ULL, 0);
+
+	/* decrease the send status command idle timer to 3us */
+	cqhci_writel(cq_host, 0x40, CQHCI_SSC1);
 }
 
 static void msdc_cqe_disable(struct mmc_host *mmc, bool recovery)
-- 
2.25.1