[PATCH 2/3] mmc: host: sdhci-sprd: Implement the request_atomic() API

[Baolin Wang <baolin.wang7@gmail.com>]

Implement the request_atomic() API for nonremovable cards, that means
we can submit next request in the irq hard handler context to reduce
latency.

Signed-off-by: Baolin Wang <baolin.wang7@gmail.com>
---
 drivers/mmc/host/sdhci-sprd.c |   28 ++++++++++++++++++++++++++--
 1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sdhci-sprd.c b/drivers/mmc/host/sdhci-sprd.c
index d346223..ae9acb8 100644
--- a/drivers/mmc/host/sdhci-sprd.c
+++ b/drivers/mmc/host/sdhci-sprd.c
@@ -426,6 +426,27 @@ static void sdhci_sprd_request(struct mmc_host *mmc, struct mmc_request *mrq)
 	sdhci_request(mmc, mrq);
 }
 
+static void sdhci_sprd_request_atomic(struct mmc_host *mmc,
+				      struct mmc_request *mrq)
+{
+	struct sdhci_host *host = mmc_priv(mmc);
+	struct sdhci_sprd_host *sprd_host = TO_SPRD_HOST(host);
+
+	host->flags |= sprd_host->flags & SDHCI_AUTO_CMD23;
+
+	/*
+	 * From version 4.10 onward, ARGUMENT2 register is also as 32-bit
+	 * block count register which doesn't support stuff bits of
+	 * CMD23 argument on Spreadtrum's sd host controller.
+	 */
+	if (host->version >= SDHCI_SPEC_410 &&
+	    mrq->sbc && (mrq->sbc->arg & SDHCI_SPRD_ARG2_STUFF) &&
+	    (host->flags & SDHCI_AUTO_CMD23))
+		host->flags &= ~SDHCI_AUTO_CMD23;
+
+	sdhci_request_atomic(mmc, mrq);
+}
+
 static int sdhci_sprd_voltage_switch(struct mmc_host *mmc, struct mmc_ios *ios)
 {
 	struct sdhci_host *host = mmc_priv(mmc);
@@ -561,6 +582,11 @@ static int sdhci_sprd_probe(struct platform_device *pdev)
 	if (ret)
 		goto pltfm_free;
 
+	if (!mmc_card_is_removable(host->mmc))
+		host->mmc_host_ops.request_atomic = sdhci_sprd_request_atomic;
+	else
+		host->always_defer_done = true;
+
 	sprd_host = TO_SPRD_HOST(host);
 	sdhci_sprd_phy_param_parse(sprd_host, pdev->dev.of_node);
 
@@ -654,8 +680,6 @@ static int sdhci_sprd_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_cleanup_host;
 
-	host->always_defer_done = true;
-
 	ret = __sdhci_add_host(host);
 	if (ret)
 		goto err_cleanup_host;
-- 
1.7.9.5