[PATCH v5 2/3] mmc: host: sdhci: Implement the request_atomic() API

[Baolin Wang]

Implement the request_atomic() ops for the sdhci driver to process
one request in the atomic context if the card is nonremovable.

Moreover, we should return BUSY flag if controller has not released
the inhibit bits to allow HSQ trying to send request again in non-atomic
context.

Suggested-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Signed-off-by: Baolin Wang <baolin.wang7@xxxxxxxxx>
---
 drivers/mmc/host/sdhci.c | 34 ++++++++++++++++++++++++++++++++++
 drivers/mmc/host/sdhci.h |  1 +
 2 files changed, 35 insertions(+)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 10b9570f48aa..0baef595de26 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2144,6 +2144,40 @@ void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
 }
 EXPORT_SYMBOL_GPL(sdhci_request);
 
+int sdhci_request_atomic(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+	struct sdhci_host *host = mmc_priv(mmc);
+	struct mmc_command *cmd;
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&host->lock, flags);
+
+	if (sdhci_present_error(host, mrq->cmd, true)) {
+		sdhci_finish_mrq(host, mrq);
+		goto out_finish;
+	}
+
+	cmd = sdhci_manual_cmd23(host, mrq) ? mrq->sbc : mrq->cmd;
+
+	/*
+	 * The HSQ may send a command in interrupt context without polling
+	 * the busy signaling, which means we should return BUSY if controller
+	 * has not released inhibit bits to allow HSQ trying to send request
+	 * again in non-atomic context. So we should not finish this request
+	 * here.
+	 */
+	if (!sdhci_send_command(host, cmd))
+		ret = -EBUSY;
+	else
+		sdhci_led_activate(host);
+
+out_finish:
+	spin_unlock_irqrestore(&host->lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(sdhci_request_atomic);
+
 void sdhci_set_bus_width(struct sdhci_host *host, int width)
 {
 	u8 ctrl;
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index a7e469c00617..4bd70da7aa00 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -776,6 +776,7 @@ void sdhci_set_power_and_bus_voltage(struct sdhci_host *host,
 void sdhci_set_power_noreg(struct sdhci_host *host, unsigned char mode,
 			   unsigned short vdd);
 void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq);
+int sdhci_request_atomic(struct mmc_host *mmc, struct mmc_request *mrq);
 void sdhci_set_bus_width(struct sdhci_host *host, int width);
 void sdhci_reset(struct sdhci_host *host, u8 mask);
 void sdhci_set_uhs_signaling(struct sdhci_host *host, unsigned timing);
-- 
2.17.1