NAND Flash Has Poor Read Performance

[志林韩]

Hello:

   We use NAND Flash : Winbond W29N02GVSIAA, but it has poor read performance.

   I did a simple read performance test:

dd if=/dev/mtdblock3 of=/dev/null bs=512 count=200000

200000+0 records in

200000+0 records out

102400000 bytes (97.7MB) copied, 30.378243 seconds, 3.2MB/s

   Then I found kernel startup log:

      [    0.415944] nand: Unknown W29N02GV

      [    0.415954] nand: 256MiB, SLC, page size: 2048, OOB size: 64  

      [    0.416336] gpmi-nand 112000.gpmi-nand: mode:4 ,failed in set feature.

   So I forced the nand to be in EDO mode 4. Then the read speed reached 10.6MB/s

      dd if=/dev/mtdblock3 of=/dev/null bs=512 count=200000

      200000+0 records in

      200000+0 records out

      102400000 bytes (97.7MB) copied, 9.188045 seconds, 10.6MB/s

   But it's still too slow for us,.

   Thanks for anyone could give me some advice to improve the read performance.

[igorpadykov]

Hi 志林 韩

for log: nand: Unknown W29N02GV - one can check if this particular part has entry in

linux/drivers/mtd/nand/nand_ids.c

nand_ids.c\nand\mtd\drivers - linux-imx - i.MX Linux kernel 

Also that nand can have many bad blocks so one can try with new one.

Best regards
igor
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[志林韩]

Hi igorpadykov

Thanks for your reply.

Does it affect its performance if it is not in the list?

[志林韩]

We use Linux kernel 3.14.52 and UBIFS.