All of lore.kernel.org
 help / color / mirror / Atom feed
From: Deepak Sikri <deepak.sikri-qxv4g6HH51o@public.gmane.org>
To: <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
Cc: spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
	spear-devel-nkJGhpqTU55BDgjK7y7TUQ@public.gmane.org,
	Deepak Sikri <deepak.sikri-qxv4g6HH51o@public.gmane.org>
Subject: [PATCH] spi/pl022: Fix the dma map/unmap calls sequencing
Date: Fri, 10 Aug 2012 13:37:59 +0530	[thread overview]
Message-ID: <1344586079-5238-1-git-send-email-deepak.sikri@st.com> (raw)

The current driver implementation for the DMA tranfers first invalidates
the cache for Rx buffers and then cleans the cache for Tx buffers before
starting the DMA transfers.

The SPIDEV framework assigns a single buffer for both reception and
transmission of data.So the above sequence of invalidating the cache and
then cleaning it does not work well when the same buffer is used for Rx
& Tx.

This patch alters the sequence, i.e first flushes the cache and then
invalidate them to ensure data integrity.

Signed-off-by: Deepak Sikri <deepak.sikri-qxv4g6HH51o@public.gmane.org>
---
 drivers/spi/spi-pl022.c |   22 +++++++++++-----------
 1 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/spi/spi-pl022.c b/drivers/spi/spi-pl022.c
index 1e33b83..2c231b7 100644
--- a/drivers/spi/spi-pl022.c
+++ b/drivers/spi/spi-pl022.c
@@ -755,10 +755,10 @@ static void *next_transfer(struct pl022 *pl022)
 static void unmap_free_dma_scatter(struct pl022 *pl022)
 {
 	/* Unmap and free the SG tables */
-	dma_unmap_sg(pl022->dma_tx_channel->device->dev, pl022->sgt_tx.sgl,
-		     pl022->sgt_tx.nents, DMA_TO_DEVICE);
 	dma_unmap_sg(pl022->dma_rx_channel->device->dev, pl022->sgt_rx.sgl,
 		     pl022->sgt_rx.nents, DMA_FROM_DEVICE);
+	dma_unmap_sg(pl022->dma_tx_channel->device->dev, pl022->sgt_tx.sgl,
+		     pl022->sgt_tx.nents, DMA_TO_DEVICE);
 	sg_free_table(&pl022->sgt_rx);
 	sg_free_table(&pl022->sgt_tx);
 }
@@ -1009,16 +1009,16 @@ static int configure_dma(struct pl022 *pl022)
 			  pl022->cur_transfer->len, &pl022->sgt_tx);
 
 	/* Map DMA buffers */
-	rx_sglen = dma_map_sg(rxchan->device->dev, pl022->sgt_rx.sgl,
-			   pl022->sgt_rx.nents, DMA_FROM_DEVICE);
-	if (!rx_sglen)
-		goto err_rx_sgmap;
-
 	tx_sglen = dma_map_sg(txchan->device->dev, pl022->sgt_tx.sgl,
 			   pl022->sgt_tx.nents, DMA_TO_DEVICE);
 	if (!tx_sglen)
 		goto err_tx_sgmap;
 
+	rx_sglen = dma_map_sg(rxchan->device->dev, pl022->sgt_rx.sgl,
+			   pl022->sgt_rx.nents, DMA_FROM_DEVICE);
+	if (!rx_sglen)
+		goto err_rx_sgmap;
+
 	/* Send both scatterlists */
 	rxdesc = dmaengine_prep_slave_sg(rxchan,
 				      pl022->sgt_rx.sgl,
@@ -1053,12 +1053,12 @@ err_txdesc:
 	dmaengine_terminate_all(txchan);
 err_rxdesc:
 	dmaengine_terminate_all(rxchan);
-	dma_unmap_sg(txchan->device->dev, pl022->sgt_tx.sgl,
+	dma_unmap_sg(txchan->device->dev, pl022->sgt_rx.sgl,
+		     pl022->sgt_rx.nents, DMA_FROM_DEVICE);
+err_rx_sgmap:
+	dma_unmap_sg(rxchan->device->dev, pl022->sgt_tx.sgl,
 		     pl022->sgt_tx.nents, DMA_TO_DEVICE);
 err_tx_sgmap:
-	dma_unmap_sg(rxchan->device->dev, pl022->sgt_rx.sgl,
-		     pl022->sgt_tx.nents, DMA_FROM_DEVICE);
-err_rx_sgmap:
 	sg_free_table(&pl022->sgt_tx);
 err_alloc_tx_sg:
 	sg_free_table(&pl022->sgt_rx);
-- 
1.7.2.2


------------------------------------------------------------------------------
Live Security Virtual Conference
Exclusive live event will cover all the ways today's security and 
threat landscape has changed and how IT managers can respond. Discussions 
will include endpoint security, mobile security and the latest in malware 
threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/

                 reply	other threads:[~2012-08-10  8:07 UTC|newest]

Thread overview: [no followups] expand[flat|nested]  mbox.gz  Atom feed

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1344586079-5238-1-git-send-email-deepak.sikri@st.com \
    --to=deepak.sikri-qxv4g6hh51o@public.gmane.org \
    --cc=grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org \
    --cc=spear-devel-nkJGhpqTU55BDgjK7y7TUQ@public.gmane.org \
    --cc=spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.