linux-kernel - [PATCH 6/7] sdhci-of: Cleanup eSDHC's set

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]

Date:	Fri, 7 Aug 2009 23:58:13 +0400
From:	Anton Vorontsov <avorontsov@...mvista.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Pierre Ossman <pierre@...man.eu>,
	Kumar Gala <galak@...nel.crashing.org>,
	David Vrabel <david.vrabel@....com>, Ben Dooks <ben@...ff.org>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	linux-kernel@...r.kernel.org, sdhci-devel@...ts.ossman.eu,
	linuxppc-dev@...abs.org
Subject: [PATCH 6/7] sdhci-of: Cleanup eSDHC's set_clock() a little bit

- Get rid of incomprehensible "if { for { if } }" construction for the
  exponential divisor calculation. The first if statement isn't correct
  at all, since it should check for "host->max_clk / pre_div / 16 >
  clock". The error doesn't cause any bugs because the check in the for
  loop does the right thing, and so the outer check becomes useless;

- For the linear divisor do the same: a single while statement is more
  readable than for + if construction;

- Add dev_dbg() that prints desired and actual clock frequency.

Signed-off-by: Anton Vorontsov <avorontsov@...mvista.com>
---
 drivers/mmc/host/sdhci-of.c |   19 ++++++++-----------
 1 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/drivers/mmc/host/sdhci-of.c b/drivers/mmc/host/sdhci-of.c
index 87aaf4b..048bc01 100644
--- a/drivers/mmc/host/sdhci-of.c
+++ b/drivers/mmc/host/sdhci-of.c
@@ -121,8 +121,8 @@ static void esdhc_writeb(struct sdhci_host *host, u8 val, int reg)
 
 static void esdhc_set_clock(struct sdhci_host *host, unsigned int clock)
 {
-	int div;
 	int pre_div = 2;
+	int div = 1;
 
 	clrbits32(host->ioaddr + ESDHC_SYSTEM_CONTROL, ESDHC_CLOCK_IPGEN |
 		  ESDHC_CLOCK_HCKEN | ESDHC_CLOCK_PEREN | ESDHC_CLOCK_MASK);
@@ -130,17 +130,14 @@ static void esdhc_set_clock(struct sdhci_host *host, unsigned int clock)
 	if (clock == 0)
 		goto out;
 
-	if (host->max_clk / 16 > clock) {
-		for (; pre_div < 256; pre_div *= 2) {
-			if (host->max_clk / pre_div < clock * 16)
-				break;
-		}
-	}
+	while (host->max_clk / pre_div / 16 > clock && pre_div < 256)
+		pre_div *= 2;
 
-	for (div = 1; div <= 16; div++) {
-		if (host->max_clk / (div * pre_div) <= clock)
-			break;
-	}
+	while (host->max_clk / pre_div / div > clock && div < 16)
+		div++;
+
+	dev_dbg(mmc_dev(host->mmc), "desired SD clock: %d, actual: %d\n",
+		clock, host->max_clk / pre_div / div);
 
 	pre_div >>= 1;
 	div--;
-- 
1.6.3.3

--
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/