omap_hsmmc: improve interrupt synchronisation
diff mbox

Message ID 4BEA5DD5.9010308@nokia.com
State New, archived
Headers show

Commit Message

Adrian Hunter May 12, 2010, 7:50 a.m. UTC
None

Patch
diff mbox

diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index c0b5021..cc0272d 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -157,12 +157,10 @@  struct omap_hsmmc_host {
 	 */
 	struct	regulator	*vcc;
 	struct	regulator	*vcc_aux;
-	struct	semaphore	sem;
 	struct	work_struct	mmc_carddetect_work;
 	void	__iomem		*base;
 	resource_size_t		mapbase;
 	spinlock_t		irq_lock; /* Prevent races with irq handler */
-	unsigned long		flags;
 	unsigned int		id;
 	unsigned int		dma_len;
 	unsigned int		dma_sg_idx;
@@ -183,6 +181,7 @@  struct omap_hsmmc_host {
 	int			protect_card;
 	int			reqs_blocked;
 	int			use_reg;
+	int			req_in_progress;
 
 	struct	omap_mmc_platform_data	*pdata;
 };
@@ -480,6 +479,27 @@  static void omap_hsmmc_stop_clock(struct omap_hsmmc_host *host)
 		dev_dbg(mmc_dev(host->mmc), "MMC Clock is not stoped\n");
 }
 
+static void omap_hsmmc_enable_irq(struct omap_hsmmc_host *host)
+{
+	unsigned int irq_mask;
+
+	if (host->use_dma)
+		irq_mask = INT_EN_MASK & ~(BRR_ENABLE | BWR_ENABLE);
+	else
+		irq_mask = INT_EN_MASK;
+
+	OMAP_HSMMC_WRITE(host->base, STAT, STAT_CLEAR);
+	OMAP_HSMMC_WRITE(host->base, ISE, irq_mask);
+	OMAP_HSMMC_WRITE(host->base, IE, irq_mask);
+}
+
+static void omap_hsmmc_disable_irq(struct omap_hsmmc_host *host)
+{
+	OMAP_HSMMC_WRITE(host->base, ISE, 0);
+	OMAP_HSMMC_WRITE(host->base, IE, 0);
+	OMAP_HSMMC_WRITE(host->base, STAT, STAT_CLEAR);
+}
+
 #ifdef CONFIG_PM
 
 /*
@@ -548,9 +568,7 @@  static int omap_hsmmc_context_restore(struct omap_hsmmc_host *host)
 		&& time_before(jiffies, timeout))
 		;
 
-	OMAP_HSMMC_WRITE(host->base, STAT, STAT_CLEAR);
-	OMAP_HSMMC_WRITE(host->base, ISE, INT_EN_MASK);
-	OMAP_HSMMC_WRITE(host->base, IE, INT_EN_MASK);
+	omap_hsmmc_disable_irq(host);
 
 	/* Do not initialize card-specific things if the power is off */
 	if (host->power_mode == MMC_POWER_OFF)
@@ -653,6 +671,8 @@  static void send_init_stream(struct omap_hsmmc_host *host)
 		return;
 
 	disable_irq(host->irq);
+
+	OMAP_HSMMC_WRITE(host->base, IE, INT_EN_MASK);
 	OMAP_HSMMC_WRITE(host->base, CON,
 		OMAP_HSMMC_READ(host->base, CON) | INIT_STREAM);
 	OMAP_HSMMC_WRITE(host->base, CMD, INIT_STREAM_CMD);
@@ -718,17 +738,7 @@  omap_hsmmc_start_command(struct omap_hsmmc_host *host, struct mmc_command *cmd,
 		mmc_hostname(host->mmc), cmd->opcode, cmd->arg);
 	host->cmd = cmd;
 
-	/*
-	 * Clear status bits and enable interrupts
-	 */
-	OMAP_HSMMC_WRITE(host->base, STAT, STAT_CLEAR);
-	OMAP_HSMMC_WRITE(host->base, ISE, INT_EN_MASK);
-
-	if (host->use_dma)
-		OMAP_HSMMC_WRITE(host->base, IE,
-				 INT_EN_MASK & ~(BRR_ENABLE | BWR_ENABLE));
-	else
-		OMAP_HSMMC_WRITE(host->base, IE, INT_EN_MASK);
+	omap_hsmmc_enable_irq(host);
 
 	host->response_busy = 0;
 	if (cmd->flags & MMC_RSP_PRESENT) {
@@ -762,13 +772,7 @@  omap_hsmmc_start_command(struct omap_hsmmc_host *host, struct mmc_command *cmd,
 	if (host->use_dma)
 		cmdreg |= DMA_EN;
 
-	/*
-	 * In an interrupt context (i.e. STOP command), the spinlock is unlocked
-	 * by the interrupt handler, otherwise (i.e. for a new request) it is
-	 * unlocked here.
-	 */
-	if (!in_interrupt())
-		spin_unlock_irqrestore(&host->irq_lock, host->flags);
+	host->req_in_progress = 1;
 
 	OMAP_HSMMC_WRITE(host->base, ARG, cmd->arg);
 	OMAP_HSMMC_WRITE(host->base, CMD, cmdreg);
@@ -783,6 +787,23 @@  omap_hsmmc_get_dma_dir(struct omap_hsmmc_host *host, struct mmc_data *data)
 		return DMA_FROM_DEVICE;
 }
 
+static void omap_hsmmc_request_done(struct omap_hsmmc_host *host, struct mmc_request *mrq)
+{
+	int dma_ch;
+
+	spin_lock(&host->irq_lock);
+	host->req_in_progress = 0;
+	dma_ch = host->dma_ch;
+	spin_unlock(&host->irq_lock);
+
+	omap_hsmmc_disable_irq(host);
+	/* Do not complete the request if DMA is still in progress */
+	if (mrq->data && host->use_dma && dma_ch != -1)
+		return;
+	host->mrq = NULL;
+	mmc_request_done(host->mmc, mrq);
+}
+
 /*
  * Notify the transfer complete to MMC core
  */
@@ -799,25 +820,19 @@  omap_hsmmc_xfer_done(struct omap_hsmmc_host *host, struct mmc_data *data)
 			return;
 		}
 
-		host->mrq = NULL;
-		mmc_request_done(host->mmc, mrq);
+		omap_hsmmc_request_done(host, mrq);
 		return;
 	}
 
 	host->data = NULL;
 
-	if (host->use_dma && host->dma_ch != -1)
-		dma_unmap_sg(mmc_dev(host->mmc), data->sg, host->dma_len,
-			omap_hsmmc_get_dma_dir(host, data));
-
 	if (!data->error)
 		data->bytes_xfered += data->blocks * (data->blksz);
 	else
 		data->bytes_xfered = 0;
 
 	if (!data->stop) {
-		host->mrq = NULL;
-		mmc_request_done(host->mmc, data->mrq);
+		omap_hsmmc_request_done(host, data->mrq);
 		return;
 	}
 	omap_hsmmc_start_command(host, data->stop, NULL);
@@ -843,10 +858,8 @@  omap_hsmmc_cmd_done(struct omap_hsmmc_host *host, struct mmc_command *cmd)
 			cmd->resp[0] = OMAP_HSMMC_READ(host->base, RSP10);
 		}
 	}
-	if ((host->data == NULL && !host->response_busy) || cmd->error) {
-		host->mrq = NULL;
-		mmc_request_done(host->mmc, cmd->mrq);
-	}
+	if ((host->data == NULL && !host->response_busy) || cmd->error)
+		omap_hsmmc_request_done(host, cmd->mrq);
 }
 
 /*
@@ -854,14 +867,19 @@  omap_hsmmc_cmd_done(struct omap_hsmmc_host *host, struct mmc_command *cmd)
  */
 static void omap_hsmmc_dma_cleanup(struct omap_hsmmc_host *host, int errno)
 {
+	int dma_ch;
+
 	host->data->error = errno;
 
-	if (host->use_dma && host->dma_ch != -1) {
+	spin_lock(&host->irq_lock);
+	dma_ch = host->dma_ch;
+	host->dma_ch = -1;
+	spin_unlock(&host->irq_lock);
+
+	if (host->use_dma && dma_ch != -1) {
 		dma_unmap_sg(mmc_dev(host->mmc), host->data->sg, host->dma_len,
 			omap_hsmmc_get_dma_dir(host, host->data));
-		omap_free_dma(host->dma_ch);
-		host->dma_ch = -1;
-		up(&host->sem);
+		omap_free_dma(dma_ch);
 	}
 	host->data = NULL;
 }
@@ -923,28 +941,21 @@  static inline void omap_hsmmc_reset_controller_fsm(struct omap_hsmmc_host *host,
 			__func__);
 }
 
-/*
- * MMC controller IRQ handler
- */
-static irqreturn_t omap_hsmmc_irq(int irq, void *dev_id)
+static void omap_hsmmc_do_irq(struct omap_hsmmc_host *host, int status)
 {
-	struct omap_hsmmc_host *host = dev_id;
 	struct mmc_data *data;
-	int end_cmd = 0, end_trans = 0, status;
-
-	spin_lock(&host->irq_lock);
-
-	if (host->mrq == NULL) {
-		OMAP_HSMMC_WRITE(host->base, STAT,
-			OMAP_HSMMC_READ(host->base, STAT));
-		/* Flush posted write */
-		OMAP_HSMMC_READ(host->base, STAT);
-		spin_unlock(&host->irq_lock);
-		return IRQ_HANDLED;
+	int end_cmd = 0, end_trans = 0;
+
+	if (!host->req_in_progress) {
+		do {
+			OMAP_HSMMC_WRITE(host->base, STAT, status);
+			/* Flush posted write */
+			status = OMAP_HSMMC_READ(host->base, STAT);
+		} while (status & INT_EN_MASK);
+		return;
 	}
 
 	data = host->data;
-	status = OMAP_HSMMC_READ(host->base, STAT);
 	dev_dbg(mmc_dev(host->mmc), "IRQ Status is %x\n", status);
 
 	if (status & ERR) {
@@ -997,15 +1008,27 @@  static irqreturn_t omap_hsmmc_irq(int irq, void *dev_id)
 	}
 
 	OMAP_HSMMC_WRITE(host->base, STAT, status);
-	/* Flush posted write */
-	OMAP_HSMMC_READ(host->base, STAT);
 
 	if (end_cmd || ((status & CC) && host->cmd))
 		omap_hsmmc_cmd_done(host, host->cmd);
 	if ((end_trans || (status & TC)) && host->mrq)
 		omap_hsmmc_xfer_done(host, data);
+}
 
-	spin_unlock(&host->irq_lock);
+/*
+ * MMC controller IRQ handler
+ */
+static irqreturn_t omap_hsmmc_irq(int irq, void *dev_id)
+{
+	struct omap_hsmmc_host *host = dev_id;
+	int status;
+
+	status = OMAP_HSMMC_READ(host->base, STAT);
+	do {
+		omap_hsmmc_do_irq(host, status);
+		/* Flush posted write */
+		status = OMAP_HSMMC_READ(host->base, STAT);
+	} while (status & INT_EN_MASK);
 
 	return IRQ_HANDLED;
 }
@@ -1205,31 +1228,47 @@  static void omap_hsmmc_config_dma_params(struct omap_hsmmc_host *host,
 /*
  * DMA call back function
  */
-static void omap_hsmmc_dma_cb(int lch, u16 ch_status, void *data)
+static void omap_hsmmc_dma_cb(int lch, u16 ch_status, void *cb_data)
 {
-	struct omap_hsmmc_host *host = data;
+	struct omap_hsmmc_host *host = cb_data;
+	struct mmc_data *data = host->mrq->data;
+	int dma_ch, req_in_progress;
 
 	if (ch_status & OMAP2_DMA_MISALIGNED_ERR_IRQ)
 		dev_dbg(mmc_dev(host->mmc), "MISALIGNED_ADRS_ERR\n");
 
-	if (host->dma_ch < 0)
+	spin_lock(&host->irq_lock);
+	if (host->dma_ch < 0) {
+		spin_unlock(&host->irq_lock);
 		return;
+	}
 
 	host->dma_sg_idx++;
 	if (host->dma_sg_idx < host->dma_len) {
 		/* Fire up the next transfer. */
-		omap_hsmmc_config_dma_params(host, host->data,
-					   host->data->sg + host->dma_sg_idx);
+		omap_hsmmc_config_dma_params(host, data,
+					   data->sg + host->dma_sg_idx);
+		spin_unlock(&host->irq_lock);
 		return;
 	}
 
-	omap_free_dma(host->dma_ch);
+	dma_unmap_sg(mmc_dev(host->mmc), data->sg, host->dma_len,
+		omap_hsmmc_get_dma_dir(host, data));
+
+	req_in_progress = host->req_in_progress;
+	dma_ch = host->dma_ch;
 	host->dma_ch = -1;
-	/*
-	 * DMA Callback: run in interrupt context.
-	 * mutex_unlock will throw a kernel warning if used.
-	 */
-	up(&host->sem);
+	spin_unlock(&host->irq_lock);
+
+	omap_free_dma(dma_ch);
+
+	/* If DMA has finished after TC, complete the request */
+	if (!req_in_progress) {
+		struct mmc_request *mrq = host->mrq;
+
+		host->mrq = NULL;
+		mmc_request_done(host->mmc, mrq);
+	}
 }
 
 /*
@@ -1238,7 +1277,7 @@  static void omap_hsmmc_dma_cb(int lch, u16 ch_status, void *data)
 static int omap_hsmmc_start_dma_transfer(struct omap_hsmmc_host *host,
 					struct mmc_request *req)
 {
-	int dma_ch = 0, ret = 0, err = 1, i;
+	int dma_ch = 0, ret = 0, i;
 	struct mmc_data *data = req->data;
 
 	/* Sanity check: all the SG entries must be aligned by block size. */
@@ -1255,23 +1294,7 @@  static int omap_hsmmc_start_dma_transfer(struct omap_hsmmc_host *host,
 		 */
 		return -EINVAL;
 
-	/*
-	 * If for some reason the DMA transfer is still active,
-	 * we wait for timeout period and free the dma
-	 */
-	if (host->dma_ch != -1) {
-		set_current_state(TASK_UNINTERRUPTIBLE);
-		schedule_timeout(100);
-		if (down_trylock(&host->sem)) {
-			omap_free_dma(host->dma_ch);
-			host->dma_ch = -1;
-			up(&host->sem);
-			return err;
-		}
-	} else {
-		if (down_trylock(&host->sem))
-			return err;
-	}
+	BUG_ON(host->dma_ch != -1);
 
 	ret = omap_request_dma(omap_hsmmc_get_dma_sync_dev(host, data),
 			       "MMC/SD", omap_hsmmc_dma_cb, host, &dma_ch);
@@ -1371,37 +1394,27 @@  static void omap_hsmmc_request(struct mmc_host *mmc, struct mmc_request *req)
 	struct omap_hsmmc_host *host = mmc_priv(mmc);
 	int err;
 
-	/*
-	 * Prevent races with the interrupt handler because of unexpected
-	 * interrupts, but not if we are already in interrupt context i.e.
-	 * retries.
-	 */
-	if (!in_interrupt()) {
-		spin_lock_irqsave(&host->irq_lock, host->flags);
-		/*
-		 * Protect the card from I/O if there is a possibility
-		 * it can be removed.
-		 */
-		if (host->protect_card) {
-			if (host->reqs_blocked < 3) {
-				/*
-				 * Ensure the controller is left in a consistent
-				 * state by resetting the command and data state
-				 * machines.
-				 */
-				omap_hsmmc_reset_controller_fsm(host, SRD);
-				omap_hsmmc_reset_controller_fsm(host, SRC);
-				host->reqs_blocked += 1;
-			}
-			req->cmd->error = -EBADF;
-			if (req->data)
-				req->data->error = -EBADF;
-			spin_unlock_irqrestore(&host->irq_lock, host->flags);
-			mmc_request_done(mmc, req);
-			return;
-		} else if (host->reqs_blocked)
-			host->reqs_blocked = 0;
-	}
+	BUG_ON(host->req_in_progress);
+	BUG_ON(host->dma_ch != -1);
+	if (host->protect_card) {
+		if (host->reqs_blocked < 3) {
+			/*
+			 * Ensure the controller is left in a consistent
+			 * state by resetting the command and data state
+			 * machines.
+			 */
+			omap_hsmmc_reset_controller_fsm(host, SRD);
+			omap_hsmmc_reset_controller_fsm(host, SRC);
+			host->reqs_blocked += 1;
+		}
+		req->cmd->error = -EBADF;
+		if (req->data)
+			req->data->error = -EBADF;
+		req->cmd->retries = 0;
+		mmc_request_done(mmc, req);
+		return;
+	} else if (host->reqs_blocked)
+		host->reqs_blocked = 0;
 	WARN_ON(host->mrq != NULL);
 	host->mrq = req;
 	err = omap_hsmmc_prepare_data(host, req);
@@ -1410,8 +1423,6 @@  static void omap_hsmmc_request(struct mmc_host *mmc, struct mmc_request *req)
 		if (req->data)
 			req->data->error = err;
 		host->mrq = NULL;
-		if (!in_interrupt())
-			spin_unlock_irqrestore(&host->irq_lock, host->flags);
 		mmc_request_done(mmc, req);
 		return;
 	}
@@ -1980,7 +1991,6 @@  static int __init omap_hsmmc_probe(struct platform_device *pdev)
 	mmc->f_min	= 400000;
 	mmc->f_max	= 52000000;
 
-	sema_init(&host->sem, 1);
 	spin_lock_init(&host->irq_lock);
 
 	host->iclk = clk_get(&pdev->dev, "ick");
@@ -2126,8 +2136,7 @@  static int __init omap_hsmmc_probe(struct platform_device *pdev)
 		}
 	}
 
-	OMAP_HSMMC_WRITE(host->base, ISE, INT_EN_MASK);
-	OMAP_HSMMC_WRITE(host->base, IE, INT_EN_MASK);
+	omap_hsmmc_disable_irq(host);
 
 	mmc_host_lazy_disable(host->mmc);
 
@@ -2247,10 +2256,7 @@  static int omap_hsmmc_suspend(struct platform_device *pdev, pm_message_t state)
 		mmc_host_enable(host->mmc);
 		ret = mmc_suspend_host(host->mmc, state);
 		if (ret == 0) {
-			OMAP_HSMMC_WRITE(host->base, ISE, 0);
-			OMAP_HSMMC_WRITE(host->base, IE, 0);
-
-
+			omap_hsmmc_disable_irq(host);
 			OMAP_HSMMC_WRITE(host->base, HCTL,
 				OMAP_HSMMC_READ(host->base, HCTL) & ~SDBP);
 			mmc_host_disable(host->mmc);