From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Mark Brown <broonie@kernel.org>, Eric Anholt <eric@anholt.net>,
Stefan Wahren <stefan.wahren@i2se.com>,
Florian Fainelli <f.fainelli@gmail.com>,
Ray Jui <rjui@broadcom.com>,
Scott Branden <sbranden@broadcom.com>,
bcm-kernel-feedback-list@broadcom.com
Cc: linux-spi@vger.kernel.org, linux-rpi-kernel@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
"Gustavo A. R. Silva" <garsilva@embeddedor.com>
Subject: [PATCH] spi: bcm2835aux: use 64-bit arithmetic instead of 32-bit
Date: Wed, 7 Feb 2018 10:00:02 -0600 [thread overview]
Message-ID: <20180207160002.GA9292@embeddedgus> (raw)
Add suffix ULL to constant 9 in order to give the compiler complete
information about the proper arithmetic to use. Notice that this
constant is used in a context that expects an expression of type
unsigned long long (64 bits, unsigned).
The expression tfr->len * 9 * 1000000 is currently being evaluated
using 32-bit arithmetic.
Addresses-Coverity-ID: 1339619
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
drivers/spi/spi-bcm2835aux.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c
index 7428091..a768c23 100644
--- a/drivers/spi/spi-bcm2835aux.c
+++ b/drivers/spi/spi-bcm2835aux.c
@@ -363,7 +363,7 @@ static int bcm2835aux_spi_transfer_one(struct spi_master *master,
* chunk getting transferred - in our case the chunk size
* is 3 bytes, so we approximate this by 9 bits/byte
*/
- xfer_time_us = tfr->len * 9 * 1000000;
+ xfer_time_us = tfr->len * 9ULL * 1000000;
do_div(xfer_time_us, spi_used_hz);
/* run in polling mode for short transfers */
--
2.7.4
next reply other threads:[~2018-02-07 16:00 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-07 16:00 Gustavo A. R. Silva [this message]
2018-02-08 8:22 ` [PATCH] spi: bcm2835aux: use 64-bit arithmetic instead of 32-bit Eric Anholt
2018-02-12 17:57 ` Gustavo A. R. Silva
2018-02-08 9:54 ` Ard Biesheuvel
2018-02-12 18:04 ` Gustavo A. R. Silva
2018-02-12 18:45 ` Ard Biesheuvel
[not found] ` <CAKv+Gu9VTkNN-6MCCuQ2jWFyDMeZKNRyPqMpTWB5jvuSw7MWeA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2018-02-12 19:10 ` Florian Fainelli
[not found] ` <bab99bbb-c84b-3413-e7f8-203c7daad8b3-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2018-02-12 19:11 ` Ard Biesheuvel
[not found] ` <CAKv+Gu9Mb7Wpzwvr=1WsUs1jXYT16DL2dYBfhSWH0HYZMYM5Nw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2018-02-12 19:14 ` Florian Fainelli
2018-02-12 19:31 ` Trent Piepho
2018-02-12 19:38 ` [PATCH] spi: bcm2835aux: Avoid 64-bit arithmetic in xfer len calc Trent Piepho
[not found] ` <20180212193814.17644-1-tpiepho-cgc2CodaaHDQT0dZR+AlfA@public.gmane.org>
2018-02-14 16:04 ` Mark Brown
2018-02-14 16:28 ` Applied "spi: bcm2835aux: Avoid 64-bit arithmetic in xfer len calc" to the spi tree Mark Brown
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