On 28/9/2018 10:24 AM, Miquel Raynal wrote:
Hi Daniel,
Daniel Mack <daniel@xxxxxxxxxx> wrote on Fri, 28 Sep 2018 09:43:18
+0200:
Hi Chris,
On 27/9/2018 11:55 PM, Chris Packham wrote:
On 27/09/18 20:56, Boris Brezillon wrote:
On Thu, 27 Sep 2018 10:11:45 +0200
Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote:
Hi Daniel,
Daniel Mack <daniel@xxxxxxxxxx> wrote on Thu, 27 Sep 2018 09:17:51
+0200:
At least on PXA3xx platforms, enabling RDY interrupts in the NDCR register
will only cause the IRQ to latch when the RDY lanes are changing, and not
in case they are already asserted.
This means that if the controller finished the command in flight before
marvell_nfc_wait_op() is called, that function will wait for a change in
the bit that can't ever happen as it is already set.
To address this race, check for the RDY bits after the IRQ was enabled,
and complete the completion immediately if the condition is already met.
This fixes a bug that was observed with a NAND chip that holds a UBIFS
parition on which file system stress tests were executed. When
marvell_nfc_wait_op() reports an error, UBI/UBIFS will eventually mount
the filesystem read-only, reporting lots of warnings along the way.
Fixes: 02f26ecf8c77 mtd: nand: add reworked Marvell NAND controller driver
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Daniel Mack <daniel@xxxxxxxxxx>
---
Sorry I haven't had the time to check on my Armada, but you figured it
out, and the fix looks good to me!
Acked-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Boris, do you plan to send another fixes PR of can I take it into
the nand/next branch?
Queued to mtd/master.
After fixing my R/B configuration I get a new error with this patch when
running stress_1 from mtd-utils-2.0.0. I don't see this without the patch.
That's strange. So your controller sets the RDY bits before it is ready? Could
you check whether only checking for NDSR_RDY(0) changes anything? Not sure
about the handling of NDSR_RDY(1) in this driver anyway ...
I suppose you mean this portion of code is not clear enough?
u32 st = readl_relaxed(nfc->regs + NDSR);
u32 ien = (~readl_relaxed(nfc->regs + NDCR)) & NDCR_ALL_INT;
/*
* RDY interrupt mask is one bit in NDCR while there are two status
* bit in NDSR (RDY[cs0/cs2] and RDY[cs1/cs3]).
*/
if (st & NDSR_RDY(1))
st |= NDSR_RDY(0);
if (!(st & ien))
return IRQ_NONE;
-> st is the status in the NDSR register which has two RDY bits, one
for each RDY line.
-> ien is a view of the NDCR register which commands the interrupts
and has one bit to enable both interrupt lines (let's call it
NDCR_RDYM).
The trick is that NDSR_RDY(0) is the same bit as NDCR_RDYM.
So whenever NDSR_RDY(1) is set, we fake NDSR_RDY(0) to be set (by
setting manually the bit in 'st') so that the (st & ien) comparison
can be true if NDSR_RDY(1) is valid and RDY interrupts are enabled.
With this in mind, I don't see why this
+ st = readl_relaxed(nfc->regs + NDSR);
+ if (st & (NDSR_RDY(0) | NDSR_RDY(1)))
+ complete(&nfc->complete);
Yeah, me neither. Chris, are you absolutely sure this is the reason? I'm
asking because it took me several tries sometimes to trigger the bug, so
is there a chance that you see an error at all times, regardless of
whether my patch is applied?
Thanks,
Daniel
