Messages in this thread Patch in this message | | | From | Sasha Levin <> | Subject | [PATCH AUTOSEL 4.14 06/19] i2c: altera: Fix potential integer overflow | Date | Thu, 5 Mar 2020 12:15:27 -0500 |
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From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
[ Upstream commit 54498e8070e19e74498a72c7331348143e7e1f8c ]
Factor out 100 from the equation and do 32-bit arithmetic (3 * clk_mhz / 10) instead of 64-bit.
Notice that clk_mhz is MHz, so the multiplication will never wrap 32 bits and there is no need for div_u64().
Addresses-Coverity: 1458369 ("Unintentional integer overflow") Fixes: 0560ad576268 ("i2c: altera: Add Altera I2C Controller driver") Suggested-by: David Laight <David.Laight@ACULAB.COM> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Reviewed-by: Thor Thayer <thor.thayer@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Sasha Levin <sashal@kernel.org> --- drivers/i2c/busses/i2c-altera.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-altera.c b/drivers/i2c/busses/i2c-altera.c index f5e1941e65b5a..a1cdcfc74acf6 100644 --- a/drivers/i2c/busses/i2c-altera.c +++ b/drivers/i2c/busses/i2c-altera.c @@ -182,7 +182,7 @@ static void altr_i2c_init(struct altr_i2c_dev *idev) /* SCL Low Time */ writel(t_low, idev->base + ALTR_I2C_SCL_LOW); /* SDA Hold Time, 300ns */ - writel(div_u64(300 * clk_mhz, 1000), idev->base + ALTR_I2C_SDA_HOLD); + writel(3 * clk_mhz / 10, idev->base + ALTR_I2C_SDA_HOLD); /* Mask all master interrupt bits */ altr_i2c_int_enable(idev, ALTR_I2C_ALL_IRQ, false); -- 2.20.1
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