From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thor Thayer Subject: Re: [PATCH] i2c: altera: Use 64-bit arithmetic instead of 32-bit Date: Mon, 10 Feb 2020 14:42:16 -0600 Message-ID: References: <20200210192656.GA8412@embeddedor> Reply-To: thor.thayer@linux.intel.com Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mga09.intel.com ([134.134.136.24]:46762 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727331AbgBJUkK (ORCPT ); Mon, 10 Feb 2020 15:40:10 -0500 In-Reply-To: <20200210192656.GA8412@embeddedor> Content-Language: en-US Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: "Gustavo A. R. Silva" Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org On 2/10/20 1:26 PM, Gustavo A. R. Silva wrote: > Add suffix ULL to constant 300 in order to avoid a potential integer > overflow and give the compiler complete information about the proper > arithmetic to use. Notice that this constant is being used in a context > that expects an expression of type u64, but it's currently evaluated > using 32-bit arithmetic. > > Addresses-Coverity: 1458369 ("Unintentional integer overflow") > Fixes: 0560ad576268 ("i2c: altera: Add Altera I2C Controller driver") > Signed-off-by: Gustavo A. R. Silva > --- > drivers/i2c/busses/i2c-altera.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/i2c/busses/i2c-altera.c b/drivers/i2c/busses/i2c-altera.c > index 5255d3755411..526f453f0ff7 100644 > --- a/drivers/i2c/busses/i2c-altera.c > +++ b/drivers/i2c/busses/i2c-altera.c > @@ -171,7 +171,8 @@ 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(div_u64(300ULL * clk_mhz, 1000), > + idev->base + ALTR_I2C_SDA_HOLD); > > /* Mask all master interrupt bits */ > altr_i2c_int_enable(idev, ALTR_I2C_ALL_IRQ, false); > Thank you. Reviewed-by: Thor Thayer