linux-kernel - [PATCH] dmaengine: pxa_dma: fix the maximum requestor line

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Message-Id: <1454941131-12308-1-git-send-email-robert.jarzmik@free.fr>
Date:	Mon,  8 Feb 2016 15:18:51 +0100
From:	Robert Jarzmik <robert.jarzmik@...e.fr>
To:	Daniel Mack <daniel@...que.org>,
	Haojian Zhuang <haojian.zhuang@...il.com>,
	Robert Jarzmik <robert.jarzmik@...e.fr>,
	Vinod Koul <vinod.koul@...el.com>
Cc:	linux-arm-kernel@...ts.infradead.org, dmaengine@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] dmaengine: pxa_dma: fix the maximum requestor line

The current number of requestor lines is limited to 31. This was an
error of a previous commit, as this number is platform dependent, and is
actually :
 - for pxa25x: 40 requestor lines
 - for pxa27x: 74 requestor lines
 - for pxa3xx: 100 requestor lines

As the driver doesn't need to know the exact number, but only an
absolute maximum value above which is it not using any flow control, set
the maximum to 0x8000 requestor lines, which should never be reached.

The previous testing did not reveal the faulty constant as on pxa[23]xx
platforms, only camera, MSL and USB are above requestor 32, and in these
only the camera has a driver using dma.

Fixes: e87ffbdf0697 ("dmaengine: pxa_dma: fix the no-requestor case")
Signed-off-by: Robert Jarzmik <robert.jarzmik@...e.fr>
---
 drivers/dma/pxa_dma.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/pxa_dma.c b/drivers/dma/pxa_dma.c
index ca6c088edc8a..817a2bdc423d 100644
--- a/drivers/dma/pxa_dma.c
+++ b/drivers/dma/pxa_dma.c
@@ -53,6 +53,7 @@
 
 #define DRCMR_MAPVLD	BIT(7)	/* Map Valid (read / write) */
 #define DRCMR_CHLNUM	0x1f	/* mask for Channel Number (read / write) */
+#define DRCMR_MAXREQST	0x7fff	/* Maximum requestor line */
 
 #define DDADR_DESCADDR	0xfffffff0	/* Address of next descriptor (mask) */
 #define DDADR_STOP	BIT(0)	/* Stop (read / write) */
@@ -473,7 +474,7 @@ static void pxad_free_phy(struct pxad_chan *chan)
 		return;
 
 	/* clear the channel mapping in DRCMR */
-	if (chan->drcmr <= DRCMR_CHLNUM) {
+	if (chan->drcmr <= DRCMR_MAXREQST) {
 		reg = pxad_drcmr(chan->drcmr);
 		writel_relaxed(0, chan->phy->base + reg);
 	}
@@ -518,7 +519,7 @@ static void phy_enable(struct pxad_phy *phy, bool misaligned)
 		"%s(); phy=%p(%d) misaligned=%d\n", __func__,
 		phy, phy->idx, misaligned);
 
-	if (phy->vchan->drcmr <= DRCMR_CHLNUM) {
+	if (phy->vchan->drcmr <= DRCMR_MAXREQST) {
 		reg = pxad_drcmr(phy->vchan->drcmr);
 		writel_relaxed(DRCMR_MAPVLD | phy->idx, phy->base + reg);
 	}
@@ -922,7 +923,7 @@ static void pxad_get_config(struct pxad_chan *chan,
 		dev_addr = chan->cfg.src_addr;
 		*dev_src = dev_addr;
 		*dcmd |= PXA_DCMD_INCTRGADDR;
-		if (chan->drcmr <= DRCMR_CHLNUM)
+		if (chan->drcmr <= DRCMR_MAXREQST)
 			*dcmd |= PXA_DCMD_FLOWSRC;
 	}
 	if (dir == DMA_MEM_TO_DEV) {
@@ -931,7 +932,7 @@ static void pxad_get_config(struct pxad_chan *chan,
 		dev_addr = chan->cfg.dst_addr;
 		*dev_dst = dev_addr;
 		*dcmd |= PXA_DCMD_INCSRCADDR;
-		if (chan->drcmr <= DRCMR_CHLNUM)
+		if (chan->drcmr <= DRCMR_MAXREQST)
 			*dcmd |= PXA_DCMD_FLOWTRG;
 	}
 	if (dir == DMA_MEM_TO_MEM)
-- 
2.1.4