linux-kernel - [ 50/59] pch_dma: Fix CTL register access issue

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20120419210615.399189799@linuxfoundation.org>
Date:	Thu, 19 Apr 2012 14:07:01 -0700
From:	Greg KH <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
	alan@...rguk.ukuu.org.uk,
	Tomoya MORINAGA <tomoya-linux@....okisemi.com>,
	Vinod Koul <vinod.koul@...el.com>,
	Tomoya MORINAGA <tomoya.rohm@...il.com>
Subject: [ 50/59] pch_dma: Fix CTL register access issue

3.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tomoya MORINAGA <tomoya-linux@....okisemi.com>

commit 0b052f4a088ddc47a5da23dd733522241314cfb4 upstream.

Currently, Mode-Control register is accessed by read-modify-write.

According to DMA hardware specifications datasheet, prohibits this method.
Because this register resets to 0 by DMA HW after DMA transfer completes.
Thus, current read-modify-write processing can cause unexpected behavior.

The datasheet says in case of writing Mode-Control register, set the value for only target channel, the others must set '11b'.
e.g. Set DMA0=01b  DMA11=10b
CTL0=33333331h
CTL2=00002333h

NOTE:
CTL0 includes DMA0~7 Mode-Control register.
CTL2 includes DMA8~11 Mode-Control register.

This patch modifies the issue.

Signed-off-by: Tomoya MORINAGA <tomoya-linux@....okisemi.com>
Signed-off-by: Vinod Koul <vinod.koul@...el.com>
Signed-off-by: Tomoya MORINAGA <tomoya.rohm@...il.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/dma/pch_dma.c |   42 +++++++++++++++++++++++++++++++-----------
 1 file changed, 31 insertions(+), 11 deletions(-)

--- a/drivers/dma/pch_dma.c
+++ b/drivers/dma/pch_dma.c
@@ -62,6 +62,9 @@
 
 #define MAX_CHAN_NR			8
 
+#define DMA_MASK_CTL0_MODE	0x33333333
+#define DMA_MASK_CTL2_MODE	0x00003333
+
 static unsigned int init_nr_desc_per_channel = 64;
 module_param(init_nr_desc_per_channel, uint, 0644);
 MODULE_PARM_DESC(init_nr_desc_per_channel,
@@ -210,10 +213,17 @@ static void pdc_set_dir(struct dma_chan
 	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
 	struct pch_dma *pd = to_pd(chan->device);
 	u32 val;
+	u32 mask_mode;
+	u32 mask_ctl;
 
 	if (chan->chan_id < 8) {
 		val = dma_readl(pd, CTL0);
 
+		mask_mode = DMA_CTL0_MODE_MASK_BITS <<
+					(DMA_CTL0_BITS_PER_CH * chan->chan_id);
+		mask_ctl = DMA_MASK_CTL0_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
+				       (DMA_CTL0_BITS_PER_CH * chan->chan_id));
+		val &= mask_mode;
 		if (pd_chan->dir == DMA_TO_DEVICE)
 			val |= 0x1 << (DMA_CTL0_BITS_PER_CH * chan->chan_id +
 				       DMA_CTL0_DIR_SHIFT_BITS);
@@ -221,18 +231,24 @@ static void pdc_set_dir(struct dma_chan
 			val &= ~(0x1 << (DMA_CTL0_BITS_PER_CH * chan->chan_id +
 					 DMA_CTL0_DIR_SHIFT_BITS));
 
+		val |= mask_ctl;
 		dma_writel(pd, CTL0, val);
 	} else {
 		int ch = chan->chan_id - 8; /* ch8-->0 ch9-->1 ... ch11->3 */
 		val = dma_readl(pd, CTL3);
 
+		mask_mode = DMA_CTL0_MODE_MASK_BITS <<
+						(DMA_CTL0_BITS_PER_CH * ch);
+		mask_ctl = DMA_MASK_CTL2_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
+						 (DMA_CTL0_BITS_PER_CH * ch));
+		val &= mask_mode;
 		if (pd_chan->dir == DMA_TO_DEVICE)
 			val |= 0x1 << (DMA_CTL0_BITS_PER_CH * ch +
 				       DMA_CTL0_DIR_SHIFT_BITS);
 		else
 			val &= ~(0x1 << (DMA_CTL0_BITS_PER_CH * ch +
 					 DMA_CTL0_DIR_SHIFT_BITS));
-
+		val |= mask_ctl;
 		dma_writel(pd, CTL3, val);
 	}
 
@@ -244,26 +260,30 @@ static void pdc_set_mode(struct dma_chan
 {
 	struct pch_dma *pd = to_pd(chan->device);
 	u32 val;
+	u32 mask_ctl;
+	u32 mask_dir;
 
 	if (chan->chan_id < 8) {
+		mask_ctl = DMA_MASK_CTL0_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
+			   (DMA_CTL0_BITS_PER_CH * chan->chan_id));
+		mask_dir = 1 << (DMA_CTL0_BITS_PER_CH * chan->chan_id +\
+				 DMA_CTL0_DIR_SHIFT_BITS);
 		val = dma_readl(pd, CTL0);
-
-		val &= ~(DMA_CTL0_MODE_MASK_BITS <<
-			(DMA_CTL0_BITS_PER_CH * chan->chan_id));
+		val &= mask_dir;
 		val |= mode << (DMA_CTL0_BITS_PER_CH * chan->chan_id);
-
+		val |= mask_ctl;
 		dma_writel(pd, CTL0, val);
 	} else {
 		int ch = chan->chan_id - 8; /* ch8-->0 ch9-->1 ... ch11->3 */
-
+		mask_ctl = DMA_MASK_CTL2_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
+						 (DMA_CTL0_BITS_PER_CH * ch));
+		mask_dir = 1 << (DMA_CTL0_BITS_PER_CH * ch +\
+				 DMA_CTL0_DIR_SHIFT_BITS);
 		val = dma_readl(pd, CTL3);
-
-		val &= ~(DMA_CTL0_MODE_MASK_BITS <<
-			(DMA_CTL0_BITS_PER_CH * ch));
+		val &= mask_dir;
 		val |= mode << (DMA_CTL0_BITS_PER_CH * ch);
-
+		val |= mask_ctl;
 		dma_writel(pd, CTL3, val);
-
 	}
 
 	dev_dbg(chan2dev(chan), "pdc_set_mode: chan %d -> %x\n",


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/