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-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <1368825532-30917-4-git-send-email-linux@prisktech.co.nz>
Date:	Sat, 18 May 2013 09:18:51 +1200
From:	Tony Prisk <linux@...sktech.co.nz>
To:	Mike Turquette <mturquette@...aro.org>
Cc:	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	vt8500-wm8505-linux-kernel@...glegroups.com,
	Tony Prisk <linux@...sktech.co.nz>
Subject: [PATCH 3/4] clk: vt8500: Remove unnecessary divisor adjustment in vtwm_dclk_set_rate()

The divisor adjustment code to ensure that a divisor is not rounded down,
thereby giving a rate higher than requested, is unnecessary and in some
instances results in the actual rate being much lower than requested due to
rounding errors.

The test is already performed in vtwm_dclk_round_rate(), which is always
called when clk_set_rate is called. Due to rounding errors in the line:
divisor = parent_rate / rate (clk-vt8500.c:160) we will sometimes end up
adjusting the divisor twice - first in round_rate and then again in set_rate.

This patch removes the test/adjustment in vtwm_dclk_set_rate.

Signed-off-by: Tony Prisk <linux@...sktech.co.nz>
---
 drivers/clk/clk-vt8500.c |    4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/clk/clk-vt8500.c b/drivers/clk/clk-vt8500.c
index ce401cf..82306f5 100644
--- a/drivers/clk/clk-vt8500.c
+++ b/drivers/clk/clk-vt8500.c
@@ -157,10 +157,6 @@ static int vt8500_dclk_set_rate(struct clk_hw *hw, unsigned long rate,
 
 	divisor =  parent_rate / rate;
 
-	/* If prate / rate would be decimal, incr the divisor */
-	if (rate * divisor < parent_rate)
-		divisor++;
-
 	if (divisor == cdev->div_mask + 1)
 		divisor = 0;
 
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ