mmc: host: sdhci-sprd: Implement the request_atomic() API

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

Moreover factor out the AUTO CMD23 checking into a separate function
to reduce duplicate code.

Signed-off-by: Baolin Wang <baolin.wang7@gmail.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/60142fe6c6c1dbba2696e775564ae2166786f0bc.1586744073.git.baolin.wang7@gmail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-sprd.c

@@ -406,7 +406,8 @@ static struct sdhci_ops sdhci_sprd_ops = {
 	.request_done = sdhci_sprd_request_done,
 };
 
-static void sdhci_sprd_request(struct mmc_host *mmc, struct mmc_request *mrq)
+static void sdhci_sprd_check_auto_cmd23(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);
@@ -422,10 +423,23 @@ static void sdhci_sprd_request(struct mmc_host *mmc, struct mmc_request *mrq)
 	    mrq->sbc && (mrq->sbc->arg & SDHCI_SPRD_ARG2_STUFF) &&
 	    (host->flags & SDHCI_AUTO_CMD23))
 		host->flags &= ~SDHCI_AUTO_CMD23;
+}
+
+static void sdhci_sprd_request(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+	sdhci_sprd_check_auto_cmd23(mmc, mrq);
 
 	sdhci_request(mmc, mrq);
 }
 
+static int sdhci_sprd_request_atomic(struct mmc_host *mmc,
+				      struct mmc_request *mrq)
+{
+	sdhci_sprd_check_auto_cmd23(mmc, mrq);
+
+	return 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);
@@ -562,6 +576,11 @@ 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);
 
@@ -655,8 +674,6 @@ 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;