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: <[email protected]> # v3.14 > Signed-off-by: Maxime Ripard <[email protected]> > --- > 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 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
