[EXT] Re: Boot failed after patch "mtd: rawnand: Support for sequential cache reads"

[Bean Huo]

Hi Miquel, 

Thanks for reaching out me, here has a TN-29-01: Increasing NAND Flash Performance.
https://media-www.micron.com/-/media/client/global/documents/products/technical-note/nand-flash/tn2901.pdf?rev=a228fd154c274ef78669b67ea097ecda


If Alexander can do tracing with oscilloscope on the parallel NAND bus, that would be help to check if this is the timing issue. 

Kind regards,
Bean

> -----Original Message-----
> From: Miquel Raynal <miquel.raynal at bootlin.com>
> Sent: Monday, May 29, 2023 1:46 PM
> To: Alexander Shiyan <eagle.alexander923 at gmail.com>
> Cc: JaimeLiao <jaimeliao.tw at gmail.com>; linux-mtd at lists.infradead.org; Bean Huo
> <beanhuo at micron.com>
> Subject: [EXT] Re: Boot failed after patch "mtd: rawnand: Support for sequential
> cache reads"
> 
> CAUTION: EXTERNAL EMAIL. Do not click links or open attachments unless you
> recognize the sender and were expecting this message.
> 
> 
> Hi Bean,
> 
> I'm adding you to this thread because I'm clueless regarding what's happening to
> Alexander.
> 
> Short recap: sequential page reads seem to fail with an MT29F Micron chip.
> Alexander is using a gpmc controller without on-die ECC, I doubt the error comes
> from the controller, so I would like to know if there is anything known to fail with
> these chips regarding the use of sequential reads. We can easily work around that
> situation if we identify the problem.
> 
> Thanks a lot,
> Miquèl
> 
> eagle.alexander923 at gmail.com wrote on Mon, 29 May 2023
> 13:33:04 +0300:
> 
> > пн, 29 мая 2023 г. в 11:12, Miquel Raynal <miquel.raynal at bootlin.com>:
> > ...
> > According to the MT29F2G08ABAEAWP datasheet, the chip supports
> > > > the READ PAGE CACHE SEQUENTIAL opcode, but with two caveats:
> > > >  4. These commands supported only with ECC disabled.
> > > >  5. Issuing a READ PAGE CACHE series (31h, 00h-31h, 3Fh) command
> > > >   when the array is busy (RDY = 1, ARDY = 0) is supported if the previous
> > > >   command was a READ PAGE (00h-30h) or READ PAGE CACHE series
> > > >   command; otherwise, it is prohibited.
> > > >
> > > > As far as I understand, the second remark suits us, since we
> > > > create the correct sequence.
> > >
> > > Exactly, we do:
> > >
> > >         READ0 (0), READSTART (30),
> > >         READCACHESEQ (31), data,
> > >         READCACHESEQ (31), data,
> > >         ...
> > >         READCACHEEND (3f), data.
> > >
> > > which is what the datasheet tells us I believe.
> > >
> > > > But the first remark can be a problem in this case.
> > >
> > > I was not aware of this limitation, it's only written in the
> > > summary, not in the details about the commands, nice finding. We
> > > need to prevent on-die ECC users from enabling this feature.
> > >
> > > But given the below trace, you're not using the on-die ECC engine,
> > > right? It looks like you're using the controller's ELM engine to
> > > perform ECC correction, so I don't see why this specific limitation
> > > would hit us. Can you confirm the ECC engine of the chip is disabled?
> >
> > Yes, on-die ECC is disabled.
> > Please advise where I can insert some debug messages to clear things up.
> >
> > > > > > omap-gpmc 50000000.gpmc: GPMC revision 6.0 ...
> > > > > > nand: device found, Manufacturer ID: 0x2c, Chip ID: 0xda
> > > > > > nand: Micron MT29F2G08ABAEAWP
> > > > > > nand: 256 MiB, SLC, erase size: 128 KiB, page size: 2048, OOB
> > > > > > size: 64
> > > > > > nand: using OMAP_ECC_BCH8_CODE_HW ECC scheme ...
> > > > > > VFS: Mounted root (squashfs filesystem) readonly on device 254:0.
> > > > > > devtmpfs: mounted
> > > > > > Freeing unused kernel image (initmem) memory: 1024K Run
> > > > > > /sbin/init as init process SQUASHFS error: lzo decompression
> > > > > > failed, data probably corrupt SQUASHFS error: Failed to read
> > > > > > block 0xd291c2: -5 SQUASHFS error: lzo decompression failed,
> > > > > > data probably corrupt SQUASHFS error: Failed to read block
> > > > > > 0xd291c2: -5 SQUASHFS error: Unable to read data cache entry
> > > > > > [d291c2] SQUASHFS error: Unable to read page, block d291c2,
> > > > > > size 14307 SQUASHFS error: Unable to read data cache entry
> > > > > > [d291c2] SQUASHFS error: Unable to read page, block d291c2,
> > > > > > size 14307 Kernel panic - not syncing: Attempted to kill init!
> > > > > > exitcode=0x00000007 CPU: 0 PID: 1 Comm: init Not tainted
> > > > > > 6.3.0+ #105 Hardware name: Generic AM33XX (Flattened Device
> > > > > > Tree)  unwind_backtrace from show_stack+0xb/0xc  show_stack
> > > > > > from dump_stack_lvl+0x2b/0x34  dump_stack_lvl from
> > > > > > panic+0xbd/0x230  panic from make_task_dead+0x1/0x120
> > > > > > make_task_dead from 0xc102ca80 ---[ end Kernel panic - not
> > > > > > syncing: Attempted to kill init!
> > > > > > exitcode=0x00000007 ]---