linux-kernel - [PATCH] i2c: i2c-stm32f7: improve loopback in timing algorithm

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 6 Mar 2019 15:12:32 +0000
From:   Bich HEMON <bich.hemon@...com>
To:     Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre TORGUE <alexandre.torgue@...com>,
        Pierre Yves MORDRET <pierre-yves.mordret@...com>,
        Wolfram Sang <wsa@...-dreams.de>,
        "linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-stm32@...md-mailman.stormreply.com" 
        <linux-stm32@...md-mailman.stormreply.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Bich HEMON <bich.hemon@...com>
Subject: [PATCH] i2c: i2c-stm32f7: improve loopback in timing algorithm

From: Nicolas Le Bayon <nicolas.le.bayon@...com>

This avoids useless loops inside the I2C timing algorithm.
Actually, we support only one possible solution per prescaler value.
So after finding a solution with a prescaler, the algorithm can
switch directly to the next prescaler value.

Signed-off-by: Nicolas Le Bayon <nicolas.le.bayon@...com>
Signed-off-by: Bich Hemon <bich.hemon@...com>
---
 drivers/i2c/busses/i2c-stm32f7.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
index 4284fc9..48337be 100644
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c
@@ -476,8 +476,12 @@ static int stm32f7_i2c_compute_timing(struct stm32f7_i2c_dev *i2c_dev,
 
 					list_add_tail(&v->node,
 						      &solutions);
+					break;
 				}
 			}
+
+			if (p_prev == p)
+				break;
 		}
 	}
 
-- 
1.9.1