On 10/28/2012 8:58 AM, Stephen Warren wrote:
On 10/26/2012 05:33 AM, Vikram Narayanan wrote:
Some nitpicks.
On 10/24/2012 10:20 AM, Stephen Warren wrote:
<snip>
+static u8 bcm2835_sdhci_readb(struct sdhci_host *host, int reg)
+{
+ u32 val = bcm2835_sdhci_raw_readl(host, (reg& ~3));
+ val = val>> (reg<< 3& 0x18)& 0xff;
+
+ return (u8)val;
+}
Can the above used magics be made as macros?
This code was taken directly from the downstream Linux kernel, so I
changed it as little as possible, to make comparisons easier. Still, if
people want I can certainly make it easier to understand the expression
a bit.
Seems reasonable.
I don't think the issue is the magic numbers so much as understanding
what the expression does; the magic are obvious then. It's simply
extracting byte n from from a u32. Would the following be more obvious:
byte_num = reg& 3;
byte_shift = bytenum * 8;
byte = (val>> byte_shift)& 0xff;
... and similar for the other functions?
This looks better to me than the former. Thanks.
~Vikram
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