Re: [REGRESSION] spi: cadence-quadspi: STIG mode results in timeouts for Micron MT25QL01 flash

["Linux regression tracking (Thorsten Leemhuis)" <regressions@xxxxxxxxxxxxx>]

On 14.10.24 14:43, Stefan Kerkmann wrote:
> 
> I have run into the same regression when probing a Micron MT25QL01 SPI-NOR flash
> on a Intel CycloneV platform (socfpga) as Yoshitaka Ikeda[1]. The regression
> manifests in read timeouts. Bisecting the issue tracked it down to commit
> "d403fb6e76bf8 spi: cadence-quadspi: use STIG mode for small reads".

Adding Dhruva Gole (author) and Mark Brown (committer) to the list of
recipients.

> Reverting
> the commit resolves the issue on v6.12-rc3. There are no custom patches applied,
> except for the debugging output mentioned in the linked thread.

The culprit afaics was merged for v6.3-rc1. Makes me wonder: would
reverting this now even an option to fix this in mainline, or would this
just lead to a regression for someone else?

Ciao, Thorsten

> The good case is as follows:
> 
> ```
> [    1.063171] **********spi_mem_op dump**************
> [    1.063183] addr: nbytes:0x0 , buswidth 0x0, dtr 0x0, val 0x0
> [    1.068093] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0x9F
> [    1.073837] data: nbytes:0x6 , buswidth 0x1, dtr 0x0, data dir 0x1
> [    1.079823] ***************************************
> [    1.086068] **********spi_mem_op dump**************
> [    1.090931] addr: nbytes:0x3 , buswidth 0x1, dtr 0x0, val 0x0
> [    1.095815] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0x5A
> [    1.101543] data: nbytes:0x10 , buswidth 0x1, dtr 0x0, data dir 0x1
> [    1.107547] ***************************************
> [    1.113835] **********spi_mem_op dump**************
> [    1.118695] addr: nbytes:0x3 , buswidth 0x1, dtr 0x0, val 0x10
> [    1.123573] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0x5A
> [    1.129395] data: nbytes:0x8 , buswidth 0x1, dtr 0x0, data dir 0x1
> [    1.135392] ***************************************
> [    1.141592] **********spi_mem_op dump**************
> [    1.146471] addr: nbytes:0x3 , buswidth 0x1, dtr 0x0, val 0x0
> [    1.151335] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0x5A
> [    1.157072] data: nbytes:0x88 , buswidth 0x1, dtr 0x0, data dir 0x1
> [    1.163058] ***************************************
> [    1.169341] **********spi_mem_op dump**************
> [    1.174219] addr: nbytes:0x3 , buswidth 0x1, dtr 0x0, val 0x30
> [    1.179082] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0x5A
> [    1.184904] data: nbytes:0x40 , buswidth 0x1, dtr 0x0, data dir 0x1
> [    1.190890] ***************************************
> [    1.197183] **********spi_mem_op dump**************
> [    1.202045] addr: nbytes:0x3 , buswidth 0x1, dtr 0x0, val 0x80
> [    1.206925] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0x5A
> [    1.212740] data: nbytes:0x8 , buswidth 0x1, dtr 0x0, data dir 0x1
> [    1.218736] ***************************************
> [    1.224916] **********spi_mem_op dump**************
> [    1.229776] addr: nbytes:0x0 , buswidth 0x0, dtr 0x0, val 0x0
> [    1.234649] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0x6
> [    1.240376] data: nbytes:0x0 , buswidth 0x0, dtr 0x0, data dir 0x0
> [    1.246283] ***************************************
> [    1.252443] **********spi_mem_op dump**************
> [    1.257314] addr: nbytes:0x0 , buswidth 0x0, dtr 0x0, val 0x0
> [    1.262176] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0xB7
> [    1.267917] data: nbytes:0x0 , buswidth 0x0, dtr 0x0, data dir 0x0
> [    1.273914] ***************************************
> [    1.280074] **********spi_mem_op dump**************
> [    1.284946] addr: nbytes:0x0 , buswidth 0x0, dtr 0x0, val 0x0
> [    1.289809] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0x4
> [    1.295544] data: nbytes:0x0 , buswidth 0x0, dtr 0x0, data dir 0x0
> [    1.301444] ***************************************
> [    1.307694] 5 fixed-partitions partitions found on MTD device ff705000.spi.0
> [    1.319593] Creating 5 MTD partitions on "ff705000.spi.0":
> [    1.325080] 0x000000000000-0x000000040000 : "preloader"
> [    1.331825] 0x000000040000-0x0000000c0000 : "bootloader"
> [    1.338645] 0x0000000c0000-0x0000000e0000 : "barebox-environment"
> [    1.346299] 0x0000000e0000-0x000000110000 : "state-storage"
> [    1.353319] 0x000000110000-0x000008000000 : "ubi"
> ```
> 
> With the STIG short read optimization enabled, the read timeouts occur:
> 
> ```
> [    0.931469] **********spi_mem_op dump**************
> [    0.931482] addr: nbytes:0x0 , buswidth 0x0, dtr 0x0, val 0x0
> [    0.936398] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0x9F
> [    0.942129] data: nbytes:0x6 , buswidth 0x1, dtr 0x0, data dir 0x1
> [    0.948132] ***************************************
> [    0.954369] **********spi_mem_op dump**************
> [    0.959233] addr: nbytes:0x3 , buswidth 0x1, dtr 0x0, val 0x0
> [    0.964117] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0x5A
> [    0.969845] data: nbytes:0x10 , buswidth 0x1, dtr 0x0, data dir 0x1
> [    0.975844] ***************************************
> [    1.482104] cadence-qspi ff705000.spi: Flash command execution timed out.
> [    1.493754] **********spi_mem_op dump**************
> [    1.493759] addr: nbytes:0x3 , buswidth 0x1, dtr 0x0, val 0x10
> [    1.498623] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0x5A
> [    1.504451] data: nbytes:0x8 , buswidth 0x1, dtr 0x0, data dir 0x1
> [    1.510438] ***************************************
> [    1.516611] spi-nor spi0.0: operation failed with -110
> [    2.026639] cadence-qspi ff705000.spi: Flash command execution timed out.
> [    2.033430] **********spi_mem_op dump**************
> [    2.033437] addr: nbytes:0x0 , buswidth 0x0, dtr 0x0, val 0x0
> [    2.038300] cmd: nbytes:0x1 , buswidth 0x1, dtr 0x0, opcode 0x6
> [    2.044041] data: nbytes:0x0 , buswidth 0x0, dtr 0x0, data dir 0x0
> [    2.049942] ***************************************
> [    2.056112] spi-nor spi0.0: operation failed with -110
> [    2.066110] spi-nor spi0.0: probe with driver spi-nor failed with error -110
> ```
> 
> The DT node for the flash is as follows:
> 
> ```
> &qspi {
> 	status = "okay";
> 
> 	flash0: flash@0 {
> 		#address-cells = <1>;
> 		#size-cells = <1>;
> 		/* Micron MT25QL01 */
> 		compatible = "n25q00", "jedec,spi-nor";
> 		reg = <0>;	/* chip select */
> 		spi-max-frequency = <100000000>;
> 		m25p,fast-read;
> 		cdns,page-size = <256>;
> 		cdns,block-size = <16>;   /* 2^16, 64KB */
> 		cdns,read-delay = <4>;    /* delay value in read data capture register */
> 		cdns,tshsl-ns = <50>;
> 		cdns,tsd2d-ns = <50>;
> 		cdns,tchsh-ns = <4>;
> 		cdns,tslch-ns = <4>;
> 	};
> };
> ```
> 
> Regards,
> Stefan Kerkmann
> 
> [1]:
> https://lore.kernel.org/lkml/OSZPR01MB70048CE259A3D63C4179199A8B659@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/#t
> 
> #regzbot introduced: d403fb6e76bf854ef0f7d84e797e51b9494788e0
> 

#regzbot poke