Re: [PATCH RFC] bcm47xxsflash: just use memcpy for reading

[Marc Kleine-Budde <mkl@pengutronix.de>]

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On 09/19/2012 02:08 PM, Rafał Miłecki wrote:
> ---
> Still have to check it with aiaiai
> ---
>  drivers/mtd/devices/bcm47xxsflash.c |   31 ++-----------------------------
>  1 files changed, 2 insertions(+), 29 deletions(-)
> 
> diff --git a/drivers/mtd/devices/bcm47xxsflash.c b/drivers/mtd/devices/bcm47xxsflash.c
> index a328872..2f8dfd4 100644
> --- a/drivers/mtd/devices/bcm47xxsflash.c
> +++ b/drivers/mtd/devices/bcm47xxsflash.c
> @@ -14,41 +14,14 @@ static int bcm47xxsflash_read(struct mtd_info *mtd, loff_t from, size_t len,
>  			      size_t *retlen, u_char *buf)
>  {
>  	struct bcma_sflash *sflash = mtd->priv;
> -	size_t bytes_read = 0;
> -	__iomem u8 *src = (__iomem u8 *)KSEG0ADDR(sflash->window + from);
> -	int i;
> -	size_t unaligned_before, unaligned_after;
>  
>  	/* Check address range */
>  	if ((from + len) > mtd->size)
>  		return -EINVAL;
>  
> -	unaligned_before = from & 0x3;
> -	unaligned_after = (from + len) & 0x3;
> +	memcpy(buf, (void *)KSEG0ADDR(sflash->window + from), len);

You should not access iomem with memcpy, there is a memcpy_fromio(), but
it's an unoptimized readb loop on arm.

Marc
>  
> -	for (i = 0; i < unaligned_before; i++) {
> -		*buf = readb(src);
> -		buf++;
> -		src++;
> -		bytes_read++;
> -	}
> -	for (i = from - unaligned_before; i < from + len - unaligned_after;
> -	     i += 4) {
> -		*(u32 *)buf = readl(src);
> -		buf += 4;
> -		src += 4;
> -		bytes_read += 4;
> -	}
> -	for (i = 0; i < unaligned_after; i++) {
> -		*buf = readb(src);
> -		buf++;
> -		src++;
> -		bytes_read++;
> -	}
> -
> -	*retlen = bytes_read;
> -
> -	return 0;
> +	return len;
>  }
>  
>  static void bcm47xxsflash_fill_mtd(struct bcma_sflash *sflash,
> 


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