On Mon, 1 Oct 2018 22:15:28 +0000 Chris Packham <Chris.Packham@xxxxxxxxxxxxxxxxxxx> wrote: > On 02/10/18 11:13, Boris Brezillon wrote: > > On Mon, 1 Oct 2018 22:01:27 +0000 > > Chris Packham <Chris.Packham@xxxxxxxxxxxxxxxxxxx> wrote: > > > >> On 02/10/18 10:41, Boris Brezillon wrote: > >>> On Mon, 1 Oct 2018 22:34:38 +0200 > >>> Boris Brezillon <boris.brezillon@xxxxxxxxxxx> wrote: > >>> > >>>>> > >>>>> I'd previously tried readl() based on the same hunch. No change. > >>>>> > >>>>> I think my snippet above might be misleading. While a delay between > >>>>> readl_relaxed() and the if should not change the outcome, this is also a > >>>>> delay between marvell_nfc_enable_int() and marvell_nfc_disable_int() > >>>>> which is probably more significant. Sure enough if I move the delay to > >>>>> just before the marvell_nfc_disable_int() the error is not seen. > >>>> > >>>> AFAICT, your timeout always happens when waiting for RDREQ, not RDYM. > >>>> So maybe disabling MRDY too early has a side-effect on the RDREQ event. > >>> > >>> Can you try with this patch [1]? It should ensure that NDSR_RDY bits > >>> are cleared before starting an operation. > >>> > >>> [1]http://code.bulix.org/lgs30c-468205 > >>> > >> > >> No luck. I applied that on top of Daniel's and got the same result. > >> > >> One thing that does look promising is the following modification of > >> Daniel's patch[1]. Which moves the RDY check to before where the > >> interrupts are enabled. > > > > Except we still don't know why this is happening, and I'm not sure I > > want to take a fix without understanding why it does fix the problem. > > Agreed. My only guess is that there is some interrupt that is missed in > the short period they are disabled when calling complete(). Disabling interrupts when taking a spinlock means masking the IRQ line, but the interrupt still exists and should be there when linux unmasks the IRQ line. I don't think this is the problem we're chasing. Looks more like something > > > Also, it looks like complete() is not called until the RDDREQ, WRDREQ > > and WRCMDREQ are cleared in the interrupt handler [1], which is weird. > > Miquel, do you happen to remember why you had to do that? > > > > [1]https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/mtd/nand/raw/marvell_nand.c?h=v4.19-rc6#n689 > > >
