patches.renesas/0397-i2c-sh_mobile-check-timing-parameters-for-valid-rang.patch

From 4230dfe425428acfa51782df22d102c04840366c Mon Sep 17 00:00:00 2001
From: Wolfram Sang <wsa+renesas@sang-engineering.com>
Date: Fri, 2 May 2014 21:15:15 +0200
Subject: i2c: sh_mobile: check timing parameters for valid range

Due to misconfiguration, it can happen that the calculated timing
parameters are out of range. Bail out if that happens. We can also
simplify some logic later because of the verified value. Also, make the
printouts of the values more precise by adding the hex-prefixes.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
(cherry picked from commit 7663ebefca8079ef0fd2fff1047d3d10af654c78)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
---
 drivers/i2c/busses/i2c-sh_mobile.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
index 9f02013eaeeb..b1d399e3e5fc 100644
--- a/drivers/i2c/busses/i2c-sh_mobile.c
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -232,6 +232,7 @@ static int sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd)
 {
 	unsigned long i2c_clk_khz;
 	u32 tHIGH, tLOW, tf;
+	uint16_t max_val;
 
 	/* Get clock rate after clock is enabled */
 	clk_prepare_enable(pd->clk);
@@ -254,15 +255,23 @@ static int sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd)
 	}
 
 	pd->iccl = sh_mobile_i2c_iccl(i2c_clk_khz, tLOW, tf);
+	pd->icch = sh_mobile_i2c_icch(i2c_clk_khz, tHIGH, tf);
+
+	max_val = pd->flags & IIC_FLAG_HAS_ICIC67 ? 0x1ff : 0xff;
+	if (pd->iccl > max_val || pd->icch > max_val) {
+		dev_err(pd->dev, "timing values out of range: L/H=0x%x/0x%x\n",
+			pd->iccl, pd->icch);
+		return -EINVAL;
+	}
+
 	/* one more bit of ICCL in ICIC */
-	if ((pd->iccl > 0xff) && (pd->flags & IIC_FLAG_HAS_ICIC67))
+	if (pd->iccl & 0x100)
 		pd->icic |= ICIC_ICCLB8;
 	else
 		pd->icic &= ~ICIC_ICCLB8;
 
-	pd->icch = sh_mobile_i2c_icch(i2c_clk_khz, tHIGH, tf);
 	/* one more bit of ICCH in ICIC */
-	if ((pd->icch > 0xff) && (pd->flags & IIC_FLAG_HAS_ICIC67))
+	if (pd->icch & 0x100)
 		pd->icic |= ICIC_ICCHB8;
 	else
 		pd->icic &= ~ICIC_ICCHB8;
@@ -717,7 +726,7 @@ static int sh_mobile_i2c_probe(struct platform_device *dev)
 	}
 
 	dev_info(&dev->dev,
-		 "I2C adapter %d with bus speed %lu Hz (L/H=%x/%x)\n",
+		 "I2C adapter %d with bus speed %lu Hz (L/H=0x%x/0x%x)\n",
 		 adap->nr, pd->bus_speed, pd->iccl, pd->icch);
 
 	return 0;
-- 
2.1.2