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* [PATCH 1/5] mmc: msm_sdcc: Fix possible circular locking dependency warning
@ 2010-12-07 10:55 Sahitya Tummala
  2010-12-07 10:55 ` [PATCH 2/5] mmc: msm_sdcc: Add prog done interrupt support Sahitya Tummala
                   ` (4 more replies)
  0 siblings, 5 replies; 10+ messages in thread
From: Sahitya Tummala @ 2010-12-07 10:55 UTC (permalink / raw)
  To: cjb, linux-mmc; +Cc: san, linux-arm-msm, Sahitya Tummala

In the context of request processing thread, data mover lock is
acquired after the host lock.  In another context, in the completion
handler of data mover the locks are acquired in the reverse order,
resulting in possible circular lock dependency warning. Hence,
schedule a tasklet to process the dma completion so as to avoid
nested locks.

Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
---
 drivers/mmc/host/msm_sdcc.c |   49 +++++++++++++++++++++++++++++--------------
 drivers/mmc/host/msm_sdcc.h |    3 ++
 2 files changed, 36 insertions(+), 16 deletions(-)

diff --git a/drivers/mmc/host/msm_sdcc.c b/drivers/mmc/host/msm_sdcc.c
index 1290d14..b147971 100644
--- a/drivers/mmc/host/msm_sdcc.c
+++ b/drivers/mmc/host/msm_sdcc.c
@@ -189,42 +189,40 @@ msmsdcc_dma_exec_func(struct msm_dmov_cmd *cmd)
 }
 
 static void
-msmsdcc_dma_complete_func(struct msm_dmov_cmd *cmd,
-			  unsigned int result,
-			  struct msm_dmov_errdata *err)
+msmsdcc_dma_complete_tlet(unsigned long data)
 {
-	struct msmsdcc_dma_data	*dma_data =
-		container_of(cmd, struct msmsdcc_dma_data, hdr);
-	struct msmsdcc_host	*host = dma_data->host;
+	struct msmsdcc_host *host = (struct msmsdcc_host *)data;
 	unsigned long		flags;
 	struct mmc_request	*mrq;
+	struct msm_dmov_errdata err;
 
 	spin_lock_irqsave(&host->lock, flags);
 	host->dma.active = 0;
 
+	err = host->dma.err;
 	mrq = host->curr.mrq;
 	BUG_ON(!mrq);
 	WARN_ON(!mrq->data);
 
-	if (!(result & DMOV_RSLT_VALID)) {
+	if (!(host->dma.result & DMOV_RSLT_VALID)) {
 		pr_err("msmsdcc: Invalid DataMover result\n");
 		goto out;
 	}
 
-	if (result & DMOV_RSLT_DONE) {
+	if (host->dma.result & DMOV_RSLT_DONE) {
 		host->curr.data_xfered = host->curr.xfer_size;
 	} else {
 		/* Error or flush  */
-		if (result & DMOV_RSLT_ERROR)
+		if (host->dma.result & DMOV_RSLT_ERROR)
 			pr_err("%s: DMA error (0x%.8x)\n",
-			       mmc_hostname(host->mmc), result);
-		if (result & DMOV_RSLT_FLUSH)
+			       mmc_hostname(host->mmc), host->dma.result);
+		if (host->dma.result & DMOV_RSLT_FLUSH)
 			pr_err("%s: DMA channel flushed (0x%.8x)\n",
-			       mmc_hostname(host->mmc), result);
-		if (err)
-			pr_err("Flush data: %.8x %.8x %.8x %.8x %.8x %.8x\n",
-			       err->flush[0], err->flush[1], err->flush[2],
-			       err->flush[3], err->flush[4], err->flush[5]);
+			       mmc_hostname(host->mmc), host->dma.result);
+
+		pr_err("Flush data: %.8x %.8x %.8x %.8x %.8x %.8x\n",
+		       err.flush[0], err.flush[1], err.flush[2],
+		       err.flush[3], err.flush[4], err.flush[5]);
 		if (!mrq->data->error)
 			mrq->data->error = -EIO;
 	}
@@ -273,6 +271,22 @@ out:
 	return;
 }
 
+static void
+msmsdcc_dma_complete_func(struct msm_dmov_cmd *cmd,
+			  unsigned int result,
+			  struct msm_dmov_errdata *err)
+{
+	struct msmsdcc_dma_data	*dma_data =
+		container_of(cmd, struct msmsdcc_dma_data, hdr);
+	struct msmsdcc_host *host = dma_data->host;
+
+	dma_data->result = result;
+	if (err)
+		memcpy(&dma_data->err, err, sizeof(struct msm_dmov_errdata));
+
+	tasklet_schedule(&host->dma_tlet);
+}
+
 static int validate_dma(struct msmsdcc_host *host, struct mmc_data *data)
 {
 	if (host->dma.channel == -1)
@@ -1118,6 +1132,9 @@ msmsdcc_probe(struct platform_device *pdev)
 	host->dmares = dmares;
 	spin_lock_init(&host->lock);
 
+	tasklet_init(&host->dma_tlet, msmsdcc_dma_complete_tlet,
+			(unsigned long)host);
+
 	/*
 	 * Setup DMA
 	 */
diff --git a/drivers/mmc/host/msm_sdcc.h b/drivers/mmc/host/msm_sdcc.h
index ff2b0f7..996990d 100644
--- a/drivers/mmc/host/msm_sdcc.h
+++ b/drivers/mmc/host/msm_sdcc.h
@@ -172,6 +172,8 @@ struct msmsdcc_dma_data {
 	struct msmsdcc_host		*host;
 	int				busy; /* Set if DM is busy */
 	int				active;
+	unsigned int			result;
+	struct msm_dmov_errdata		err;
 };
 
 struct msmsdcc_pio_data {
@@ -235,6 +237,7 @@ struct msmsdcc_host {
 	int			cmdpoll;
 	struct msmsdcc_stats	stats;
 
+	struct tasklet_struct	dma_tlet;
 	/* Command parameters */
 	unsigned int		cmd_timeout;
 	unsigned int		cmd_pio_irqmask;
-- 
1.7.1

--
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.

^ permalink raw reply related	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2010-12-08  6:10 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2010-12-07 10:55 [PATCH 1/5] mmc: msm_sdcc: Fix possible circular locking dependency warning Sahitya Tummala
2010-12-07 10:55 ` [PATCH 2/5] mmc: msm_sdcc: Add prog done interrupt support Sahitya Tummala
2010-12-07 18:27   ` Daniel Walker
2010-12-08  6:10     ` Sahitya Tummala
2010-12-07 10:55 ` [PATCH 3/5] mmc: msm_sdcc: Reset SDCC in case of data transfer errors Sahitya Tummala
2010-12-07 18:33   ` Daniel Walker
2010-12-07 10:55 ` [PATCH 4/5] mmc: msm_sdcc: Fix bug in PIO mode when data size is not word aligned Sahitya Tummala
2010-12-07 10:55 ` [PATCH 5/5] mmc: msm_sdcc: Check for only DATA_END interrupt to end a request Sahitya Tummala
2010-12-07 18:15 ` [PATCH 1/5] mmc: msm_sdcc: Fix possible circular locking dependency warning Daniel Walker
2010-12-08  6:04   ` Sahitya Tummala

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