Hi Maxime,
On 23/01/2015 16:41, Maxime Ripard wrote:
> The NDDB register holds the data that are needed by the read and write
> commands.
>
> However, during a read PIO access, the datasheet specifies that after each 32
> bits read in that register, when BCH is enabled, we have to make sure that the
> RDDREQ bit is set in the NDSR register.
>
> This fixes an issue that was seen on the Armada 385, and presumably other mvebu
> SoCs, when a read on a newly erased page would end up in the driver reporting a
> timeout from the NAND.
>
> Cc: <stable@xxxxxxxxxxxxxxx>
It would help the stable maintainer if you could indicate since which commit or
kernel release this fix should be applied.
> Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/mtd/nand/pxa3xx_nand.c | 36 ++++++++++++++++++++++++++++++------
> 1 file changed, 30 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c
> index 96b0b1d27df1..320c2ab14d4e 100644
> --- a/drivers/mtd/nand/pxa3xx_nand.c
> +++ b/drivers/mtd/nand/pxa3xx_nand.c
> @@ -480,6 +480,30 @@ static void disable_int(struct pxa3xx_nand_info *info, uint32_t int_mask)
> nand_writel(info, NDCR, ndcr | int_mask);
> }
>
> +static void drain_fifo(struct pxa3xx_nand_info *info,
> + void *data,
> + int len)
> +{
> + u32 *dst = (u32 *)data;
> +
> + if (info->ecc_bch) {
> + while (len--) {
> + *dst++ = nand_readl(info, NDDB);
> +
> + /*
> + * According to the datasheet, when reading
> + * from NDDB with BCH enabled, after each 32
> + * bits reads, we have to make sure that the
> + * NDSR.RDDREQ bit is set
> + */
> + while (!(nand_readl(info, NDSR) & NDSR_RDDREQ))
> + cpu_relax();
Are we sure that we won't be blocked here?
If not, what about adding a timeout?
Thanks,
Gregory
> + }
> + } else {
> + __raw_readsl(info->mmio_base + NDDB, data, len);
> + }
> +}
> +
> static void handle_data_pio(struct pxa3xx_nand_info *info)
> {
> unsigned int do_bytes = min(info->data_size, info->chunk_size);
> @@ -496,14 +520,14 @@ static void handle_data_pio(struct pxa3xx_nand_info *info)
> DIV_ROUND_UP(info->oob_size, 4));
> break;
> case STATE_PIO_READING:
> - __raw_readsl(info->mmio_base + NDDB,
> - info->data_buff + info->data_buff_pos,
> - DIV_ROUND_UP(do_bytes, 4));
> + drain_fifo(info,
> + info->data_buff + info->data_buff_pos,
> + DIV_ROUND_UP(do_bytes, 4));
>
> if (info->oob_size > 0)
> - __raw_readsl(info->mmio_base + NDDB,
> - info->oob_buff + info->oob_buff_pos,
> - DIV_ROUND_UP(info->oob_size, 4));
> + drain_fifo(info,
> + info->oob_buff + info->oob_buff_pos,
> + DIV_ROUND_UP(info->oob_size, 4));
> break;
> default:
> dev_err(&info->pdev->dev, "%s: invalid state %d\n", __func__,
>
--
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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