linux-kernel - [PATCH 4.2.y-ckt 128/211] i2c: img-scb: do dummy writes before fifo access

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: <1452023119-25647-129-git-send-email-kamal@canonical.com>
Date:	Tue,  5 Jan 2016 11:43:56 -0800
From:	Kamal Mostafa <kamal@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Sifan Naeem <sifan.naeem@...tec.com>,
	Wolfram Sang <wsa@...-dreams.de>,
	Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 4.2.y-ckt 128/211] i2c: img-scb: do dummy writes before fifo access

4.2.8-ckt1 -stable review patch.  If anyone has any objections, please let me know.

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

From: Sifan Naeem <sifan.naeem@...tec.com>

commit 2aefb1bd4101235be7d9f0d5ac8d56aa979f6081 upstream.

Move scb_wr_rd_fence to before reading from fifo and writing to
fifo to make sure the the first read/write is done after the required
number of cycles.

Fixes: commit 27bce457d588 ("i2c: img-scb: Add Imagination Technologies I2C SCB driver")
Signed-off-by: Sifan Naeem <sifan.naeem@...tec.com>
Acked-by: James Hogan <james.hogan@...tec.com>
Reviewed-by: James Hartley <james.hartley@...tec.com>
Signed-off-by: Wolfram Sang <wsa@...-dreams.de>
Signed-off-by: Kamal Mostafa <kamal@...onical.com>
---
 drivers/i2c/busses/i2c-img-scb.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-img-scb.c b/drivers/i2c/busses/i2c-img-scb.c
index 5c3c615..0368d91 100644
--- a/drivers/i2c/busses/i2c-img-scb.c
+++ b/drivers/i2c/busses/i2c-img-scb.c
@@ -534,6 +534,7 @@ static void img_i2c_read_fifo(struct img_i2c *i2c)
 		u32 fifo_status;
 		u8 data;
 
+		img_i2c_wr_rd_fence(i2c);
 		fifo_status = img_i2c_readl(i2c, SCB_FIFO_STATUS_REG);
 		if (fifo_status & FIFO_READ_EMPTY)
 			break;
@@ -542,7 +543,6 @@ static void img_i2c_read_fifo(struct img_i2c *i2c)
 		*i2c->msg.buf = data;
 
 		img_i2c_writel(i2c, SCB_READ_FIFO_REG, 0xff);
-		img_i2c_wr_rd_fence(i2c);
 		i2c->msg.len--;
 		i2c->msg.buf++;
 	}
@@ -554,12 +554,12 @@ static void img_i2c_write_fifo(struct img_i2c *i2c)
 	while (i2c->msg.len) {
 		u32 fifo_status;
 
+		img_i2c_wr_rd_fence(i2c);
 		fifo_status = img_i2c_readl(i2c, SCB_FIFO_STATUS_REG);
 		if (fifo_status & FIFO_WRITE_FULL)
 			break;
 
 		img_i2c_writel(i2c, SCB_WRITE_DATA_REG, *i2c->msg.buf);
-		img_i2c_wr_rd_fence(i2c);
 		i2c->msg.len--;
 		i2c->msg.buf++;
 	}
-- 
1.9.1

--
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/