Hi Miquel,
I am testing last nand/next branch with the MP1 board, and i get an issue since this patch was applied.
When I read the SLC NAND using nandump tool (reading page 0 and page 1), the OOB is not displayed at expected. For page 1, oob is displayed when for page 0 the first data of the page are displayed.
The nanddump command used is: nanddump -c -o -l 0x2000 /dev/mtd9
Page 0: OOB Data: 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00 |.ELF............| OOB Data: 03 00 28 00 01 00 00 00 a4 03 00 00 34 00 00 00 |..(.........4...| OOB Data: 7c 11 00 00 00 04 00 05 34 00 20 00 06 00 28 00 ||.......4. ...(.| OOB Data: 1b 00 1a 00 01 00 00 00 00 00 00 00 00 00 00 00 |................| OOB Data: 00 00 00 00 10 05 00 00 10 05 00 00 05 00 00 00 |................| OOB Data: 00 00 01 00 01 00 00 00 e8 0e 00 00 e8 0e 01 00 |................| OOB Data: e8 0e 01 00 44 01 00 00 48 01 00 00 06 00 00 00 |....D...H.......| OOB Data: 00 00 01 00 02 00 00 00 f0 0e 00 00 f0 0e 01 00 |................| OOB Data: f0 0e 01 00 10 01 00 00 10 01 00 00 06 00 00 00 |................| OOB Data: 04 00 00 00 04 00 00 00 f4 00 00 00 f4 00 00 00 |................| OOB Data: f4 00 00 00 44 00 00 00 44 00 00 00 04 00 00 00 |....D...D.......| OOB Data: 04 00 00 00 51 e5 74 64 00 00 00 00 00 00 00 00 |....Q.td........| OOB Data: 00 00 00 00 00 00 00 00 00 00 00 00 06 00 00 00 |................| OOB Data: 10 00 00 00 52 e5 74 64 e8 0e 00 00 e8 0e 01 00 |....R.td........|
Page 1: OOB Data: ff ff 94 25 8c 3c c7 44 e7 c0 b7 b0 92 5e 50 fb |...%.<.D.....^P.| OOB Data: 80 ca a3 de e2 73 b4 4e 58 39 fe b4 85 76 65 31 |.....s.NX9...ve1| OOB Data: 48 86 91 f3 58 0b 59 df 2c 08 75 8b 6f 48 36 a6 |H...X.Y.,.u.oH6.| OOB Data: bc 16 61 58 db 52 08 75 8b 6f 48 36 a6 bc 16 61 |..aX.R.u.oH6...a| OOB Data: 58 db 52 08 75 8b 6f 48 36 a6 bc 16 61 58 db 52 |X.R.u.oH6...aX.R| OOB Data: 08 75 8b 6f 48 36 a6 bc 16 61 58 db 52 08 75 8b |.u.oH6...aX.R.u.| OOB Data: 6f 48 36 a6 bc 16 61 58 db 52 ff ff ff ff ff ff |oH6...aX.R......| OOB Data: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| OOB Data: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| OOB Data: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| OOB Data: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| OOB Data: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| OOB Data: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| OOB Data: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
I have checked what is happening in rawnand_enable_cont_reads function, and for page 0, con_read.ongoing = true when for page 1 con_read.ongoing = false
page 0: [ 51.785623] rawnand_enable_cont_reads: page=0, col=0, readlen=4096, mtd->writesize=4096 [ 51.793751] rawnand_enable_cont_reads: end_page=1, end_col=0 [ 51.799356] rawnand_enable_cont_reads: con_read.ongoing=1
page 1: [ 53.493337] rawnand_enable_cont_reads: page=1, col=0, readlen=4096, mtd->writesize=4096 [ 53.501413] rawnand_enable_cont_reads: end_page=1, end_col=0 [ 53.507013] rawnand_enable_cont_reads: con_read.ongoing=0
I do not expect con_read.ongoing set to true when we read one page.
I have also dumped what happened when we read the bad block table and it is also strange for me in particular the value end_page.
[ 1.581940] nand: device found, Manufacturer ID: 0x2c, Chip ID: 0xd3 [ 1.581966] nand: Micron MT29F8G08ABACAH4 [ 1.581974] nand: 1024 MiB, SLC, erase size: 256 KiB, page size: 4096, OOB size: 224 [ 1.582379] rawnand_enable_cont_reads: page=262080, col=0, readlen=5, mtd->writesize=4096 [ 1.582411] rawnand_enable_cont_reads: end_page=0, end_col=5 [ 1.582419] rawnand_enable_cont_reads: con_read.ongoing=0 [ 1.585817] Bad block table found at page 262080, version 0x01 [ 1.585943] rawnand_enable_cont_reads: page=262080, col=0, readlen=5, mtd->writesize=4096 [ 1.585960] rawnand_enable_cont_reads: end_page=0, end_col=5 [ 1.585968] rawnand_enable_cont_reads: con_read.ongoing=0 [ 1.586677] rawnand_enable_cont_reads: page=262016, col=0, readlen=5, mtd->writesize=4096 [ 1.586700] rawnand_enable_cont_reads: end_page=0, end_col=5 [ 1.586708] rawnand_enable_cont_reads: con_read.ongoing=0 [ 1.587139] Bad block table found at page 262016, version 0x01 [ 1.587168] rawnand_enable_cont_reads: page=262081, col=5, readlen=1019, mtd->writesize=4096 [ 1.587181] rawnand_enable_cont_reads: end_page=0, end_col=1024 [ 1.587189] rawnand_enable_cont_reads: con_read.ongoing=0 [ 1.587672] rawnand_enable_cont_reads: page=262081, col=1024, readlen=5, mtd->writesize=4096 [ 1.587692] rawnand_enable_cont_reads: end_page=0, end_col=1029 [ 1.587700] rawnand_enable_cont_reads: con_read.ongoing=0
I currently do not understand the logic implemented but there is something suspect around end_page variable.
end_page = DIV_ROUND_UP(col + readlen, mtd->writesize); => So, if i have well understood, end_page is the number of pages we are going to read.
if (page + 1 > end_page) { => We are comparing the page that we are starting to read with the number of pages to read and not the last page to read
chip->cont_read.first_page = page; chip->cont_read.last_page = end_page; => first_page is the first page to read and last page is the number of pages to read.
Before this patch, chip->cont_read.last_page = page + ((readlen >> chip->page_shift) & chip->pagemask); => last page was the last page to read.
Regards, Christophe Kerello.
On 12/22/23 12:37, Miquel Raynal wrote:
On Fri, 2023-12-15 at 12:32:08 UTC, Miquel Raynal wrote:
The current logic is probably fine but is a bit convoluted. Plus, we don't want partial pages to be part of the sequential operation just in case the core would optimize the page read with a subpage read (which would break the sequence). This may happen on the first and last page only, so if the start offset or the end offset is not aligned with a page boundary, better avoid them to prevent any risk.
Cc: stable@vger.kernel.org Fixes: 003fe4b9545b ("mtd: rawnand: Support for sequential cache reads") Signed-off-by: Miquel Raynal miquel.raynal@bootlin.com
Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next.
Miquel
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