| From cb067d241301185fc90df7f8718a6d73e852707c Mon Sep 17 00:00:00 2001 |
| From: "Gustavo A. R. Silva" <gustavo@embeddedor.com> |
| Date: Tue, 11 Feb 2020 08:47:04 -0600 |
| Subject: [PATCH] i2c: altera: Fix potential integer overflow |
| |
| commit 54498e8070e19e74498a72c7331348143e7e1f8c upstream. |
| |
| 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: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/i2c/busses/i2c-altera.c b/drivers/i2c/busses/i2c-altera.c |
| index 5255d3755411..1de23b4f3809 100644 |
| --- a/drivers/i2c/busses/i2c-altera.c |
| +++ b/drivers/i2c/busses/i2c-altera.c |
| @@ -171,7 +171,7 @@ 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); |
| -- |
| 2.7.4 |
| |
