RE: [PATCH v2 4/4] spi: cadence-quadspi: use STIG mode for small reads

[Yoshitaka Ikeda <ikeda@xxxxxxxxxxxx>]

Hi Dhruva,

Sorry for the late reply as I was on a long vacation.

> Thanks for sharing, I went through and couldn't really find any major changes
> at the controller level.
> So I am wondering if some specific sequence of flash operations on your
> device is exposing some issues in the driver's STIG reads.

Thank you for looking into this.

> Please can you share some logs with the following patch:
> I am trying to see a pattern that may be causing issues.
> I am unable to reproduce this on my end at the moment.

The logs obtained with the patch applied are as follows:

- Error at startup
  - Kernel log
[    0.980598] **********spi_mem_op dump**************
[    0.980613] addr: nbytes:0x0 , buswidth 0x0, dtr 0x0, val 0x0
[    0.984223] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0x9F
[    0.988656] data: nbytes:0x6 , buswidth 0x1, dtr 0x0, data dir 0x1
[    0.993362] ***************************************
[    0.998329] spi-nor spi0.0: found mt25ql512a, expected n25q512a
[    1.006574] **********spi_mem_op dump**************
[    1.006583] addr: nbytes:0x3 , buswidth 0x1, dtr 0x0, val 0x0
[    1.010150] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0x5A
[    1.014596] data: nbytes:0x10 , buswidth 0x1, dtr 0x0, data dir 0x1
[    1.019285] ***************************************
[    1.524271] cadence-qspi ff705000.flash: Flash command execution timed out.
[    1.533483] **********spi_mem_op dump**************
[    1.533489] addr: nbytes:0x3 , buswidth 0x1, dtr 0x0, val 0x10
[    1.537055] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0x5A
[    1.541579] data: nbytes:0x8 , buswidth 0x1, dtr 0x0, data dir 0x1
[    1.546266] ***************************************
[    1.551123] spi-nor spi0.0: operation failed with -110
[    1.558531] spi-nor spi0.0: mt25ql512a (65536 Kbytes)

- Error at access
  - Access command and log
# hexdump -Cv /dev/mtdblock0
hexdump: /dev/mtdblock0: Input/output error

  - Kernel log
[   75.401297] cadence-qspi ff705000.flash: QSPI is still busy after 500ms timeout.
[   75.401337] **********spi_mem_op dump**************
[   75.401343] addr: nbytes:0x4 , buswidth 0x1, dtr 0x0, val 0x0
[   75.401354] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0xC
[   75.401364] data: nbytes:0x200 , buswidth 0x1, dtr 0x0, data dir 0x1
[   75.401373] ***************************************
[   75.401382] spi-nor spi0.0: operation failed with -110
[   75.401407] I/O error, dev mtdblock0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 4 prio class 2
[   75.911339] cadence-qspi ff705000.flash: QSPI is still busy after 500ms timeout.
[   75.911372] **********spi_mem_op dump**************
[   75.911379] addr: nbytes:0x4 , buswidth 0x1, dtr 0x0, val 0x1000
[   75.911390] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0xC
[   75.911399] data: nbytes:0x200 , buswidth 0x1, dtr 0x0, data dir 0x1
[   75.911409] ***************************************
[   75.911417] spi-nor spi0.0: operation failed with -110
[   75.911443] I/O error, dev mtdblock0, sector 8 op 0x0:(READ) flags 0x80700 phys_seg 3 prio class 2
[   76.421333] cadence-qspi ff705000.flash: QSPI is still busy after 500ms timeout.
[   76.421365] **********spi_mem_op dump**************
[   76.421371] addr: nbytes:0x4 , buswidth 0x1, dtr 0x0, val 0x2000
[   76.421383] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0xC
[   76.421393] data: nbytes:0x200 , buswidth 0x1, dtr 0x0, data dir 0x1
[   76.421403] ***************************************
[   76.421411] spi-nor spi0.0: operation failed with -110
[   76.421436] I/O error, dev mtdblock0, sector 16 op 0x0:(READ) flags 0x80700 phys_seg 2 prio class 2
[   76.931330] cadence-qspi ff705000.flash: QSPI is still busy after 500ms timeout.
[   76.931365] **********spi_mem_op dump**************
[   76.931371] addr: nbytes:0x4 , buswidth 0x1, dtr 0x0, val 0x3000
[   76.931382] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0xC
[   76.931392] data: nbytes:0x200 , buswidth 0x1, dtr 0x0, data dir 0x1
[   76.931401] ***************************************
[   76.931410] spi-nor spi0.0: operation failed with -110
[   76.931437] I/O error, dev mtdblock0, sector 24 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2
[   77.441297] cadence-qspi ff705000.flash: QSPI is still busy after 500ms timeout.
[   77.441330] **********spi_mem_op dump**************
[   77.441337] addr: nbytes:0x4 , buswidth 0x1, dtr 0x0, val 0x0
[   77.441347] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0xC
[   77.441357] data: nbytes:0x200 , buswidth 0x1, dtr 0x0, data dir 0x1
[   77.441367] ***************************************
[   77.441375] spi-nor spi0.0: operation failed with -110
[   77.441401] I/O error, dev mtdblock0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2
[   77.441423] Buffer I/O error on dev mtdblock0, logical block 0, async page read

-- 
Thanks and Regards,
Yoshitaka Ikeda