On 03.05.2016 18:53, Marek Vasut wrote:
On 05/02/2016 05:20 PM, Stefan Roese wrote:
On 29.04.2016 12:13, Marek Vasut wrote:
On 28.04.2016 00:36, Marek Vasut wrote:
The indirect write code is buggy pile of nastiness which fails horribly
when the system runs fast enough to saturate the controller. The failure
results in some pages (256B) not being written to the flash. This can be
observed on systems which run with Dcache enabled and L2 cache enabled,
like the Altera SoCFPGA.
This patch replaces the whole unmaintainable indirect write implementation
with the one from upcoming Linux CQSPI driver, which went through multiple
rounds of thorough review and testing. While this makes the patch look
terrifying and violates all best-practices of software development, all
the patch does is it plucks out duplicate ad-hoc code distributed across
the driver and replaces it with more compact code doing exactly the same
thing.
Signed-off-by: Marek Vasut <ma...@denx.de>
Cc: Anatolij Gustschin <ag...@denx.de>
Cc: Chin Liang See <cl...@altera.com>
Cc: Dinh Nguyen <dingu...@opensource.altera.com>
Cc: Jagan Teki <jt...@openedev.com>
Cc: Pavel Machek <pa...@denx.de>
Cc: Stefan Roese <s...@denx.de>
Cc: Vignesh R <vigne...@ti.com>
I've applied both patches and tested them on SR1500 (SPI-NOR used
for booting and redundant environment). This is what I get upon
"saveeenv":
=> saveenv
Saving Environment to SPI Flash...
SF: Detected N25Q128 with page size 256 Bytes, erase size 64 KiB, total 16 MiB
Erasing SPI flash...Writing to SPI flash...data abort
pc : [<3ff8368a>] lr : [<3ff8301b>]
reloc pc : [<010216ca>] lr : [<0102105b>]
sp : 3bf54eb8 ip : 3ff82f69 fp : 00000002
r10: 00000000 r9 : 3bf5dee8 r8 : ffff0000
r7 : 00000001 r6 : 3bf54f9b r5 : 00000001 r4 : 3bf5e520
r3 : 00000000 r2 : 3bf54f9b r1 : 00000001 r0 : ffa00000
Flags: nZCv IRQs off FIQs off Mode SVC_32
Resetting CPU ...
resetting ...
U-Boot SPL 2016.05-rc3-00009-ge1bf9b8 (Apr 29 2016 - 11:25:46)
Any idea, what might be going wrong here?
Does it work without the patch ?
Yes, of course. I wouldn't have posted as a reply to this patch
if this is not the root cause.
*grumble*
?
The board is using SPI NOR for env storage from the beginning.
It only happens if you use redundant env in SPI NOR.
Where does your PC point to at the time
of the crash ,which function is it ?
Its in cadence_qspi_apb_indirect_write_execute().
I debugged this issue a bit and found the following problem
in cadence_qspi_apb_indirect_write_execute():
saveenv issues a 1-byte SPI write transfer with a non 4-byte
aligned txbuf. This causes the data-abort here. Here my small
patch that fixes the problem:
Thanks, see below.
diff --git a/drivers/spi/cadence_qspi_apb.c b/drivers/spi/cadence_qspi_apb.c
index ac47c6f..021a3e8 100644
--- a/drivers/spi/cadence_qspi_apb.c
+++ b/drivers/spi/cadence_qspi_apb.c
@@ -745,7 +745,15 @@ int cadence_qspi_apb_indirect_write_execute(struct
cadence_spi_platdata *plat,
while (remaining > 0) {
write_bytes = remaining > page_size ? page_size : remaining;
- writesl(plat->ahbbase, txbuf, DIV_ROUND_UP(write_bytes, 4));
+
+ /*
+ * Handle non 4-byte aligned access differently to avoid
+ * data-aborts
+ */
+ if (((u32)txbuf % 4) || (write_bytes % 4))
+ writesb(plat->ahbbase, txbuf, write_bytes);
+ else
+ writesl(plat->ahbbase, txbuf, write_bytes >> 2);
ret = wait_for_bit("QSPI", plat->regbase +
CQSPI_REG_SDRAMLEVEL,
CQSPI_REG_SDRAMLEVEL_WR_MASK <<
Please fell free to use this patch as-is and squash it into
your patches or enhance it while doing this. The read function
is also missing this unaligned handling.
Im afraid of the performance hit that we can suffer if we use byte-level
access for every unaligned buffer.
This is why is wrote: "or enhance it while doing this". You might want
to change the code to first write the (optionally) unaligned bytes,
then the aligned bytes via writesl() and last the (optionally) unaligned
bytes.
What do you think
about using a bounce-buffer instead ?
I would prefer the simple solution I've drafted above.
And of course the Linux driver version as well.
Does linux use unaligned buffers internally ?
Frankly, I don't know for sure. But I suspect, that you can also
see unaligned buffers (and sizes!!!) in Linux as well. And you
can't just write a different amount of data to the SPI NOR, which
happens when you use DIV_ROUND_UP on an unaligned size.
Thanks,
Stefan
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