linux-kernel - [PATCH 1/4] mtd: sh_flctl: let flctl_dma_fifo0

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Message-Id: <1430553430-21396-1-git-send-email-hofrat@osadl.org>
Date:	Sat,  2 May 2015 09:57:07 +0200
From:	Nicholas Mc Guire <hofrat@...dl.org>
To:	David Woodhouse <dwmw2@...radead.org>
Cc:	Brian Norris <computersforpeace@...il.com>,
	Vinod Koul <vinod.koul@...el.com>,
	Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>,
	Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>,
	Wolfram Sang <wsa@...-dreams.de>,
	Arnd Bergmann <arnd@...db.de>, linux-mtd@...ts.infradead.org,
	linux-kernel@...r.kernel.org, Nicholas Mc Guire <hofrat@...dl.org>
Subject: [PATCH 1/4] mtd: sh_flctl: let flctl_dma_fifo0_transfer return 0 on success

wait_for_completion_timeout() returns unsigned long not int so the check
for <= should be == and the type unsigned long. With that fixup the return
value of flctl_dma_fifo0_transfer can be changed to 0 for success. This
changes the failure return value for wait_for_completion_timeout to
-ETIMEDOUT and implicitly 0 on success by initializing ret to 0.
The call-sites are fixed up to check for == 0 rather than > 0 as well.

Signed-off-by: Nicholas Mc Guire <hofrat@...dl.org>
---

V2: As suggested by Laurent Pinchart <laurent.pinchart@...asonboard.com>
    the expected success return value is 0 so rather than just fixing up
    wait_for_completion_timeout return handling the return value of
    flctl_dma_fifo0_transfer should be adjusted.

call sites:
read_fiforeg,write_ec_fiforeg assume > 0 == success
are fixed up to check for == 0 for success
and the comment in flctl_dma_fifo0_transfe 
        /* ret > 0 is success */
        return ret;
is dropped since returning 0 on success is the expected.

Patch was compile tested with ap325rxa_defconfig (implies
CONFIG_MTD_NAND_SH_FLCTL=y)

Patch is against 4.1-rc1 (localversion-next is -next-20150501)

 drivers/mtd/nand/sh_flctl.c |   13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/mtd/nand/sh_flctl.c b/drivers/mtd/nand/sh_flctl.c
index c3ce81c..9b032dd 100644
--- a/drivers/mtd/nand/sh_flctl.c
+++ b/drivers/mtd/nand/sh_flctl.c
@@ -353,7 +353,8 @@ static int flctl_dma_fifo0_transfer(struct sh_flctl *flctl, unsigned long *buf,
 	dma_addr_t dma_addr;
 	dma_cookie_t cookie = -EINVAL;
 	uint32_t reg;
-	int ret;
+	int ret = 0;
+	unsigned long time_left;
 
 	if (dir == DMA_FROM_DEVICE) {
 		chan = flctl->chan_fifo0_rx;
@@ -388,13 +389,14 @@ static int flctl_dma_fifo0_transfer(struct sh_flctl *flctl, unsigned long *buf,
 		goto out;
 	}
 
-	ret =
+	time_left =
 	wait_for_completion_timeout(&flctl->dma_complete,
 				msecs_to_jiffies(3000));
 
-	if (ret <= 0) {
+	if (time_left == 0) {
 		dmaengine_terminate_all(chan);
 		dev_err(&flctl->pdev->dev, "wait_for_completion_timeout\n");
+		ret = -ETIMEDOUT;
 	}
 
 out:
@@ -404,7 +406,6 @@ out:
 
 	dma_unmap_single(chan->device->dev, dma_addr, len, dir);
 
-	/* ret > 0 is success */
 	return ret;
 }
 
@@ -428,7 +429,7 @@ static void read_fiforeg(struct sh_flctl *flctl, int rlen, int offset)
 
 	/* initiate DMA transfer */
 	if (flctl->chan_fifo0_rx && rlen >= 32 &&
-		flctl_dma_fifo0_transfer(flctl, buf, rlen, DMA_DEV_TO_MEM) > 0)
+		flctl_dma_fifo0_transfer(flctl, buf, rlen, DMA_DEV_TO_MEM) == 0)
 			goto convert;	/* DMA success */
 
 	/* do polling transfer */
@@ -487,7 +488,7 @@ static void write_ec_fiforeg(struct sh_flctl *flctl, int rlen,
 
 	/* initiate DMA transfer */
 	if (flctl->chan_fifo0_tx && rlen >= 32 &&
-		flctl_dma_fifo0_transfer(flctl, buf, rlen, DMA_MEM_TO_DEV) > 0)
+		flctl_dma_fifo0_transfer(flctl, buf, rlen, DMA_MEM_TO_DEV) == 0)
 			return;	/* DMA success */
 
 	/* do polling transfer */
-- 
1.7.10.4

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