linux-kernel - [PATCH 3/3] mmc: host: omap_hsmmc: Add custom card detect irq handler

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Date:	Tue, 16 Jun 2015 16:07:19 +0530
From:	Vignesh R <vigneshr@...com>
To:	Ulf Hansson <ulf.hansson@...aro.org>
CC:	Andreas Fenkart <afenkart@...il.com>,
	Tony Lindgren <tony@...mide.com>, NeilBrown <neilb@...e.de>,
	Vignesh R <vigneshr@...com>, <linux-mmc@...r.kernel.org>,
	<linux-omap@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH 3/3] mmc: host: omap_hsmmc: Add custom card detect irq handler

Usually when there is an error in transfer, DTO/CTO or other error
interrupts are raised. But if the card is unplugged in the middle of a
data transfer, it is observed that, neither completion(success) or
timeout(error) interrupts are raised. Hence, the mmc-core is waiting
for-ever for the transfer to complete. This results failure to recognise
sd card on the next insertion.
The only way to solve this is to introduce code to detect this condition
and recover on card insertion (in hsmmc specific cd_irq). Hence,
introduce cd_irq and add code to clear mmc_request that is pending from
the failed transaction.

Signed-off-by: Vignesh R <vigneshr@...com>
---
 drivers/mmc/host/omap_hsmmc.c | 73 ++++++++++++++++++++++++++++++++++-
 1 file changed, 72 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index fb4bfefd9250..ec1fff3c0c9c 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -221,6 +221,12 @@ struct omap_hsmmc_host {
 #define HSMMC_WAKE_IRQ_ENABLED	(1 << 2)
 	struct omap_hsmmc_next	next_data;
 	struct	omap_hsmmc_platform_data	*pdata;
+	/*
+	 * flag to determine whether card was removed during data
+	 * transfer
+	 */
+	bool                    transfer_incomplete;
+
 
 	/* return MMC cover switch state, can be NULL if not supported.
 	 *
@@ -867,6 +873,26 @@ static void omap_hsmmc_request_done(struct omap_hsmmc_host *host, struct mmc_req
 }
 
 /*
+ * Cleanup incomplete card removal sequence. This will make sure the
+ * next card enumeration is clean.
+ */
+static void omap_hsmmc_request_clear(struct omap_hsmmc_host *host,
+				     struct mmc_request *mrq)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&host->irq_lock, flags);
+	host->req_in_progress = 0;
+	host->dma_ch = -1;
+	spin_unlock_irqrestore(&host->irq_lock, flags);
+
+	mmc_request_done(host->mmc, mrq);
+	if (host->mmc->card)
+		mmc_card_set_removed(host->mmc->card);
+	host->mrq = NULL;
+}
+
+/*
  * Notify the transfer complete to MMC core
  */
 static void
@@ -1248,6 +1274,47 @@ static irqreturn_t omap_hsmmc_cover_irq(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+/*
+ * irq handler to notify the core about card insertion/removal
+ */
+static irqreturn_t omap_hsmmc_cd_irq(int irq, void *dev_id)
+{
+	struct omap_hsmmc_host *host = mmc_priv(dev_id);
+	int carddetect = mmc_gpio_get_cd(host->mmc);
+	struct mmc_request *mrq = host->mrq;
+
+	/*
+	 * If the card was removed in the middle of data transfer last
+	 * time, the TC/CC/timeout interrupt is not raised due to which
+	 * mmc_request is not cleared. Hence, this card insertion will
+	 * still see pending mmc_request. Clear the request to make sure
+	 * that this card enumeration is successful.
+	 */
+	if (!carddetect && mrq && host->transfer_incomplete) {
+		omap_hsmmc_disable_irq(host);
+		dev_info(host->dev,
+			 "card removed during transfer last time\n");
+		hsmmc_command_incomplete(host, -ENOMEDIUM, 1);
+		omap_hsmmc_request_clear(host, host->mrq);
+		dev_info(host->dev, "recovery done\n");
+	}
+	host->transfer_incomplete = false;
+
+	mmc_detect_change(host->mmc, (HZ * 200) / 1000);
+
+	/*
+	 * The current mmc_request is usually null before card removal
+	 * sequence is complete. It may not be null if TC/CC interrupt
+	 * never happens due to removal of card during a data
+	 * transfer. Set a flag to indicate mmc_request was not null
+	 * in order to do cleanup on next card insertion.
+	 */
+	if (carddetect && mrq)
+		host->transfer_incomplete = true;
+
+	return IRQ_HANDLED;
+}
+
 static void omap_hsmmc_dma_callback(void *param)
 {
 	struct omap_hsmmc_host *host = param;
@@ -1918,7 +1985,7 @@ static int omap_hsmmc_probe(struct platform_device *pdev)
 	struct mmc_host *mmc;
 	struct omap_hsmmc_host *host = NULL;
 	struct resource *res;
-	int ret, irq;
+	int ret, irq, len;
 	const struct of_device_id *match;
 	dma_cap_mask_t mask;
 	unsigned tx_req, rx_req;
@@ -1980,6 +2047,10 @@ static int omap_hsmmc_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_gpio;
 
+	/* register cd_irq, if cd-gpios property is specified in dt */
+	if (of_find_property(host->dev->of_node, "cd-gpios", &len))
+		mmc_gpio_set_cd_isr(mmc, omap_hsmmc_cd_irq);
+
 	platform_set_drvdata(pdev, host);
 
 	if (pdev->dev.of_node)
-- 
2.4.1

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