mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Lokesh Vutla <lokeshvutla@ti.com>
To: <gregkh@linuxfoundation.org>
Cc: <santosh.shilimkar@ti.com>, <linux-omap@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>, <lokeshvutla@ti.com>
Subject: [PATCH V2 1/8] memory: emif: Fix the lpmode timeout calculation
Date: Sat, 16 Mar 2013 11:46:41 +0530	[thread overview]
Message-ID: <1363414608-7448-2-git-send-email-lokeshvutla@ti.com> (raw)
In-Reply-To: <1363414608-7448-1-git-send-email-lokeshvutla@ti.com>

The driver tries to round up the specified timeout cycles to
the next power of 2 value. This should be done defore updating
timeout variable.
Correcting this here.

Reported-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
---
Changes since V1: 
	Updated Changelog and $subject
	Added a comment describing timeout calculation.

 drivers/memory/emif.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/memory/emif.c b/drivers/memory/emif.c
index df08736..508763c 100644
--- a/drivers/memory/emif.c
+++ b/drivers/memory/emif.c
@@ -728,13 +728,17 @@ static u32 get_pwr_mgmt_ctrl(u32 freq, struct emif_data *emif, u32 ip_rev)
 	/* Timeout based on DDR frequency */
 	timeout = freq >= freq_threshold ? timeout_perf : timeout_pwr;
 
-	/* The value to be set in register is "log2(timeout) - 3" */
+	/*
+	 * The value to be set in register is "log2(timeout) - 3"
+	 * if timeout < 16 load 0 in register
+	 * if timeout is not a power of 2, round to next highest power of 2
+	 */
 	if (timeout < 16) {
 		timeout = 0;
 	} else {
-		timeout = __fls(timeout) - 3;
 		if (timeout & (timeout - 1))
-			timeout++;
+			timeout <<= 1;
+		timeout = __fls(timeout) - 3;
 	}
 
 	switch (lpmode) {
-- 
1.7.9.5


  reply	other threads:[~2013-03-16  6:17 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-16  6:16 [PATCH V2 0/8] memory: emif: miscellaneous bug fixes for EMIF driver Lokesh Vutla
2013-03-16  6:16 ` Lokesh Vutla [this message]
2013-03-16  6:16 ` [PATCH V2 2/8] memory: emif: setup LP settings on freq update Lokesh Vutla
2013-03-16  6:16 ` [PATCH V2 3/8] memory: emif: handle overflow for timing for LP mode Lokesh Vutla
2013-03-16  6:16 ` [PATCH V2 4/8] memory: emif: Handle devices which are not rated for >85C Lokesh Vutla
2013-03-16  6:16 ` [PATCH V2 5/8] memory: emif: use restart if power_off not present when out of spec Lokesh Vutla
2013-03-16  6:16 ` [PATCH V2 6/8] memory: emif: Fix the incorrect 'size' parameter in memcpy Lokesh Vutla
2013-03-16  6:16 ` [PATCH V2 7/8] memory: emif: errata i743: Prohibit usage of Power-Down mode Lokesh Vutla
2013-03-16  6:16 ` [PATCH V2 8/8] memory: emif: Load the correct custom config values from dt Lokesh Vutla

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1363414608-7448-2-git-send-email-lokeshvutla@ti.com \
    --to=lokeshvutla@ti.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-omap@vger.kernel.org \
    --cc=santosh.shilimkar@ti.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox

all inboxes | Powered by JetHome®