[PATCH v2] mtd mxc_nand: use 32bit copy functions
Uwe Kleine-König
u.kleine-koenig at pengutronix.de
Tue May 29 05:12:54 EDT 2012
Hello,
On Tue, May 29, 2012 at 10:16:09AM +0200, Sascha Hauer wrote:
> The following commit changes the function used to copy from/to
> the hardware buffer to memcpy_[from|to]io. This does not work
> since the hardware cannot handle the byte accesses used by these
> functions. Instead of reverting this patch introduce 32bit
> correspondents of these functions.
Hmm, I didn't run an mtd test suite, but on mx27 it worked for me. IMHO
it's surprising that memcpy used to work, but memcpy_fromio doesn't. I
wouldn't expect a different semantic (apart from normal vs. __iomem
memory). And I wonder what will break when ARM's memcpy_fromio et al.
is optimized.
> | commit 5775ba36ea9c760c2d7e697dac04f2f7fc95aa62
> | Author: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
> | Date: Tue Apr 24 10:05:22 2012 +0200
> |
> | mtd: mxc_nand: fix several sparse warnings about incorrect address space
> |
> | Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
> | Signed-off-by: Artem Bityutskiy <artem.bityutskiy at linux.intel.com>
>
> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
> Cc: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
> ---
>
> v2: remove volatile, fix line over 80 characters
I'm not sure about the need for volatile. I don't have my C Reference
handy, but maybe adding volatile prevents the compilier issuing code
that e.g. uses a different word size?! Not sure if it matters for a
static and so maybe inlined function.
Still:
Acked-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
Thanks
Uwe
>
> drivers/mtd/nand/mxc_nand.c | 37 +++++++++++++++++++++++++++++--------
> 1 file changed, 29 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c
> index fd14966..17ddcf0 100644
> --- a/drivers/mtd/nand/mxc_nand.c
> +++ b/drivers/mtd/nand/mxc_nand.c
> @@ -273,6 +273,26 @@ static struct nand_ecclayout nandv2_hw_eccoob_4k = {
>
> static const char *part_probes[] = { "RedBoot", "cmdlinepart", "ofpart", NULL };
>
> +static void memcpy32_fromio(void *trg, const void __iomem *src, size_t size)
> +{
> + int i;
> + u32 *t = trg;
> + const __iomem u32 *s = src;
> +
> + for (i = 0; i < (size >> 2); i++)
> + *t++ = __raw_readl(s++);
> +}
> +
> +static void memcpy32_toio(void __iomem *trg, const void *src, int size)
> +{
> + int i;
> + u32 __iomem *t = trg;
> + const u32 *s = src;
> +
> + for (i = 0; i < (size >> 2); i++)
> + __raw_writel(*s++, t++);
> +}
> +
> static int check_int_v3(struct mxc_nand_host *host)
> {
> uint32_t tmp;
> @@ -519,7 +539,7 @@ static void send_read_id_v3(struct mxc_nand_host *host)
>
> wait_op_done(host, true);
>
> - memcpy_fromio(host->data_buf, host->main_area0, 16);
> + memcpy32_fromio(host->data_buf, host->main_area0, 16);
> }
>
> /* Request the NANDFC to perform a read of the NAND device ID. */
> @@ -535,7 +555,7 @@ static void send_read_id_v1_v2(struct mxc_nand_host *host)
> /* Wait for operation to complete */
> wait_op_done(host, true);
>
> - memcpy_fromio(host->data_buf, host->main_area0, 16);
> + memcpy32_fromio(host->data_buf, host->main_area0, 16);
>
> if (this->options & NAND_BUSWIDTH_16) {
> /* compress the ID info */
> @@ -797,16 +817,16 @@ static void copy_spare(struct mtd_info *mtd, bool bfrom)
>
> if (bfrom) {
> for (i = 0; i < n - 1; i++)
> - memcpy_fromio(d + i * j, s + i * t, j);
> + memcpy32_fromio(d + i * j, s + i * t, j);
>
> /* the last section */
> - memcpy_fromio(d + i * j, s + i * t, mtd->oobsize - i * j);
> + memcpy32_fromio(d + i * j, s + i * t, mtd->oobsize - i * j);
> } else {
> for (i = 0; i < n - 1; i++)
> - memcpy_toio(&s[i * t], &d[i * j], j);
> + memcpy32_toio(&s[i * t], &d[i * j], j);
>
> /* the last section */
> - memcpy_toio(&s[i * t], &d[i * j], mtd->oobsize - i * j);
> + memcpy32_toio(&s[i * t], &d[i * j], mtd->oobsize - i * j);
> }
> }
>
> @@ -1070,7 +1090,8 @@ static void mxc_nand_command(struct mtd_info *mtd, unsigned command,
>
> host->devtype_data->send_page(mtd, NFC_OUTPUT);
>
> - memcpy_fromio(host->data_buf, host->main_area0, mtd->writesize);
> + memcpy32_fromio(host->data_buf, host->main_area0,
> + mtd->writesize);
> copy_spare(mtd, true);
> break;
>
> @@ -1086,7 +1107,7 @@ static void mxc_nand_command(struct mtd_info *mtd, unsigned command,
> break;
>
> case NAND_CMD_PAGEPROG:
> - memcpy_toio(host->main_area0, host->data_buf, mtd->writesize);
> + memcpy32_toio(host->main_area0, host->data_buf, mtd->writesize);
> copy_spare(mtd, false);
> host->devtype_data->send_page(mtd, NFC_INPUT);
> host->devtype_data->send_cmd(host, command, true);
> --
> 1.7.10
>
>
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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