Current implementation of sdhci_s3c_consider_clock() is highly
inefficient due to multiple integer divisions by variable performed in a
loop. Since only divisors that are powers of two are considered, this
patch replaces them with respective shifts, removing all the integer
divisions.
Signed-off-by: Tomasz Figa <tomasz.figa@xxxxxxxxx>
---
drivers/mmc/host/sdhci-s3c.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/mmc/host/sdhci-s3c.c b/drivers/mmc/host/sdhci-s3c.c
index 6debda9..52770d5 100644
--- a/drivers/mmc/host/sdhci-s3c.c
+++ b/drivers/mmc/host/sdhci-s3c.c
@@ -144,7 +144,7 @@ static unsigned int sdhci_s3c_consider_clock(struct sdhci_s3c *ourhost,
{
unsigned long rate;
struct clk *clksrc = ourhost->clk_bus[src];
- int div;
+ int shift;
if (!clksrc)
return UINT_MAX;
@@ -160,15 +160,15 @@ static unsigned int sdhci_s3c_consider_clock(struct sdhci_s3c *ourhost,
rate = clk_get_rate(clksrc);
- for (div = 1; div < 256; div *= 2) {
- if ((rate / div) <= wanted)
+ for (shift = 0; shift < 8; ++shift) {
+ if ((rate >> shift) <= wanted)
break;
}
dev_dbg(&ourhost->pdev->dev, "clk %d: rate %ld, want %d, got %ld\n",
- src, rate, wanted, rate / div);
+ src, rate, wanted, rate >> shift);
- return wanted - (rate / div);
+ return wanted - (rate >> shift);
}
/**
--
1.8.5.2
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