Re: [PATCH try#2] [MTD/MAPS] Blackfin BF5xx Maps: Handle the case where flash memory and ethernet mac/phy are mapped onto the same async bank

From: JÃrn Engel
Date: Mon May 12 2008 - 08:27:25 EST


On Sun, 3 February 2008 14:32:35 +0800, Bryan Wu wrote:
> +
> +static void bf5xx_copy_from(struct map_info *map, void *to, unsigned long from, ssize_t len)
> +{
> + unsigned long i;
> + map_word test;
> +
> + if ((unsigned long)to & 0x1) {
> + for (i = 0; i < len / 2 * 2; i += 2) {
> + test = bf5xx_read(map, from + i);
> + put_unaligned(test.x[0], (__le16 *)(to + i));
> + }
> + } else {
> + for (i = 0; i < len / 2 * 2; i += 2) {
> + test = bf5xx_read(map, from + i);
> + *((u16*)(to + i)) = test.x[0];
^^^^^^^^^^^^^^^^^

I'm not particularly fond of such constructs, maybe because I have such
a hard time understanding what the code actually does.

How about:
u16 *foo = to;

for (i = 0; i < (len & ~1); i++) {
test = bf5xx_read(map, from + 2 * i);
foo[i] = test.x[0];
}

With perhaps a better name than "foo" and the same conversion in the
rest of the function as well?

> + }
> + }
> +
> + if (len & 0x1) {
> + test = bf5xx_read(map, from + i);
> + *((u8*)(to + i)) = (u8)test.x[0];
> + }
> +}

JÃrn

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