On 02/18/2015 07:32 AM, 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
> bytes 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> # v3.14
> Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/mtd/nand/pxa3xx_nand.c | 48 ++++++++++++++++++++++++++++++++++++------
> 1 file changed, 42 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c
> index 96b0b1d27df1..bc677362bc73 100644
> --- a/drivers/mtd/nand/pxa3xx_nand.c
> +++ b/drivers/mtd/nand/pxa3xx_nand.c
> @@ -480,6 +480,42 @@ 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)
> +{
> + if (info->ecc_bch) {
> + int timeout;
> +
> + /*
> + * According to the datasheet, when reading from NDDB
> + * with BCH enabled, after each 32 bytes reads, we
> + * have to make sure that the NDSR.RDDREQ bit is set.
> + *
> + * Drain the FIFO 8 32 bits reads at a time, and skip
> + * the polling on the last read.
> + */
> + while (len > 8) {
> + __raw_readsl(info->mmio_base + NDDB, data, 8);
> +
> + for (timeout = 0;
> + !(nand_readl(info, NDSR) & NDSR_RDDREQ);
> + timeout++) {
> + if (timeout >= 5) {
> + dev_err(&info->pdev->dev,
> + "Timeout on RDDREQ while draining the FIFO\n");
> + return;
> + }
> +
> + mdelay(1);
This is probably a stupid nit.. but here it goes is it any difference if
udelay is used here?
Does this makes anything better/worse?
--
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com
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