[PATCH] amba: consolidate PrimeCell magic

Jassi Brar jassisinghbrar at gmail.com
Tue Aug 16 04:56:49 EDT 2011


On Tue, Aug 16, 2011 at 2:09 PM, Russell King - ARM Linux
<linux at arm.linux.org.uk> wrote:
> On Tue, Aug 16, 2011 at 02:08:18PM +0530, Jassi Brar wrote:
>> On 16 August 2011 14:05, Russell King - ARM Linux
>> <linux at arm.linux.org.uk> wrote:
>> > On Tue, Aug 16, 2011 at 01:57:08PM +0530, Jassi Brar wrote:
>> >> On Mon, Aug 15, 2011 at 3:25 PM, Linus Walleij
>> >> <linus.walleij at stericsson.com> wrote:
>> >> > +static inline u32 amba_get_magic(void __iomem *base, u32 size, u8 offset)
>> >> > +{
>> >> > +       u32 magic;
>> >> > +       int i;
>> >> > +
>> >> > +       for (magic = 0, i = 0; i < 4; i++)
>> >> > +               magic |= (readl(base + size - offset + 4 * i) & 255)
>> >> > +                       << (i * 8);
>> >> 0xff looks much better than 255, esp when we play with bits.
>> >> Also you might simply use readb and drop the sieve ?
>> >
>> > You're making the assumption that using byte reads are permitted.  Given
>> > that these are described as 32-bit registers, and some primecells require
>> > reads of certain sizes, I believe the code to be the most correct solution.
>> >
>> If you notice the '?'
>> I already doubt that, so I simply asked Linus to ponder the possibility.
>
> Stop being an idiot.
>
Yup. Sorry, I misread your reply this time. Thanks for the info.



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