[PATCH] [ARM] orion5x: accelerate NAND on the TS-78xx

[linux@arm.linux.org.uk (Russell King - ARM Linux)]

On Tue, Jan 04, 2011 at 11:51:59PM +0000, Alexander Clouter wrote:
> The NAND supports 32bit reads and writes so lets stop shunting 8bit
> chunks across the bus.
> 
> Doing a dumb 'dd' benchmark, this increases performance roughly like so:
>  * read: 1.3MB/s to 3.4MB/s
>  * write: 614kB/s to 882kB/s

Try something like the below.  It's slightly more typing, but the
underlying string IO functions should improve your transfer speed.
Note that they won't do endian conversions.

> 
> Signed-off-by: Alexander Clouter <alex@digriz.org.uk>
> ---
>  arch/arm/mach-orion5x/ts78xx-setup.c |   42 ++++++++++++++++++++++++++++++++++
>  1 files changed, 42 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/mach-orion5x/ts78xx-setup.c b/arch/arm/mach-orion5x/ts78xx-setup.c
> index 9a5d1ef..bcc21fe 100644
> --- a/arch/arm/mach-orion5x/ts78xx-setup.c
> +++ b/arch/arm/mach-orion5x/ts78xx-setup.c
> @@ -191,6 +191,46 @@ static int ts78xx_ts_nand_dev_ready(struct mtd_info *mtd)
>  	return readb(TS_NAND_CTRL) & 0x20;
>  }
>  
> +static void ts78xx_ts_nand_write_buf(struct mtd_info *mtd,
> +			const uint8_t *buf, int len)
> +{
> +	struct nand_chip *chip = mtd->priv;
> +	void __iomem *io_base = chip->IO_ADDR_W;
> +	uint32_t *buf32;
> +	int i = 0;
> +
> +	while (len && (unsigned int)buf & 3) {
> +		writeb(*buf++, io_base);
> +		len--;
> +	}
> +	buf32 = (uint32_t *)buf;
> +	while (i < len/4)
> +		writel(buf32[i++], io_base);
> +	i *= 4;
> +	while (i < len)
> +		writeb(buf[i++], io_base);

	unsigned long off = ((unsigned long)buf & 3);
	int sz;

	if (off) {
		sz = min(4 - off, len);
		writesb(io_base, buf, sz);
		buf += sz;
		len -= sz;
	}

	sz = len >> 2;
	if (sz) {
		u32 *buf32 = (u32 *)buf;
		writesl(io_base, buf32, sz);
		buf += sz << 2;
		len -= sz << 2;
	}

	if (len)
		writesb(io_base, buf, len);

> +}
> +
> +static void ts78xx_ts_nand_read_buf(struct mtd_info *mtd,
> +			uint8_t *buf, int len)
> +{
> +	struct nand_chip *chip = mtd->priv;
> +	void __iomem *io_base = chip->IO_ADDR_R;
> +	uint32_t *buf32;
> +	int i = 0;
> +
> +	while (len && (unsigned int)buf & 3) {
> +		*buf++ = readb(io_base);
> +		len--;
> +	}
> +	buf32 = (uint32_t *)buf;
> +	while (i < len/4)
> +		buf32[i++] = readl(io_base);
> +	i *= 4;
> +	while (i < len)
> +		buf[i++] = readb(io_base);

	unsigned long off = ((unsigned long)buf & 3);
	int sz;

	if (off) {
		sz = min(4 - off, len);
		readsb(io_base, buf, sz);
		buf += sz;
		len -= sz;
	}

	sz = len >> 2;
	if (sz) {
		u32 *buf32 = (u32 *)buf;
		readsl(io_base, buf32, sz);
		buf += sz << 2;
		len -= sz << 2;
	}

	if (len)
		readsb(io_base, buf, len);

> +}
> +
>  const char *ts_nand_part_probes[] = { "cmdlinepart", NULL };
>  
>  static struct mtd_partition ts78xx_ts_nand_parts[] = {
> @@ -233,6 +273,8 @@ static struct platform_nand_data ts78xx_ts_nand_data = {
>  		 */
>  		.cmd_ctrl		= ts78xx_ts_nand_cmd_ctrl,
>  		.dev_ready		= ts78xx_ts_nand_dev_ready,
> +		.write_buf		= ts78xx_ts_nand_write_buf,
> +		.read_buf		= ts78xx_ts_nand_read_buf,
>  	},
>  };
>  
> -- 
> 1.7.2.3
> 
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