Messages in this thread | | | Date | Fri, 12 May 2023 16:49:18 +0200 | From | Miquel Raynal <> | Subject | Re: [PATCH v3 6/6] mtd: rawnand: meson: rename node for chip select |
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Hi Arseniy,
I'm adding Rafał & Michael: any idea what could be wrong? The behavior below does not look expected at all, but I thought we (= Rafał, mainly) already sorted this out?
> >>>>>>> On Wed, May 10, 2023 at 1:13 PM Arseniy Krasnov > >>>>>>> <AVKrasnov@sberdevices.ru> wrote: > >>>>>>>> > >>>>>>>> This renames node with values for chip select from "reg" to "cs". It is > >>>>>>>> needed because when OTP access is enabled on the attached storage, MTD > >>>>>>>> subsystem registers this storage in the NVMEM subsystem. NVMEM in turn > >>>>>>>> tries to use "reg" node in its own manner, supposes that it has another > >>>>>>>> layout. All of this leads to device initialization failure. > >>>>>>> In general: if we change the device-tree interface (in this case: > >>>>>>> replacing a "reg" with a "cs" property) the dt-bindings have to be > >>>>>>> updated as well. > >>>>>> > >>>>>> True, and I would add, bindings should not be broken. > >>>>> > >>>>> I see, that's true. That is bad way to change bindings. > >>>>> > >>>>>> > >>>>>>> Documentation/devicetree/bindings/mtd/nand-controller.yaml and > >>>>>>> Documentation/devicetree/bindings/mtd/amlogic,meson-nand.yaml show > >>>>>>> that the chip select of a NAND chip is specified with a "reg" > >>>>>>> property. > >>>>>> > >>>>>> All NAND controller binding expect the chip-select to be in the > >>>>>> 'reg' property, very much like a spi device would use reg to store the > >>>>>> cs as well: the reg property tells you how you address the device. > >>>>>> > >>>>>> I also fully agree with Martin's comments below. Changing reg is likely > >>>>>> a wrong approach :) > >>>>>> > >>>>>>> Also the code has to be backwards compatible with old .dtbs. > >>>>>>> > >>>>>>>> Example: > >>>>>>>> > >>>>>>>> [...] nvmem mtd0-user-otp: nvmem: invalid reg on /soc/bus@ffe00000/... > >>>>>>>> [...] mtd mtd0: Failed to register OTP NVMEM device > >>>>>>>> [...] meson-nand ffe07800.nfc: failed to register MTD device: -22 > >>>>>>>> [...] meson-nand ffe07800.nfc: failed to init NAND chips > >>>>>>>> [...] meson-nand: probe of ffe07800.nfc failed with error -22 > >>>>>>> This is odd - can you please share your definition of the &nfc node? > >>>>> > >>>>> Sure, here it is: > >>>>> > >>>>> mtd_nand: nfc@7800 { > >>>>> compatible = "amlogic,meson-axg-nfc"; > >>>>> ... > >>>>> nand@0 { > >>>>> reg = <0>; > >>>>> }; > >>>>> } > >>>>> > >>>>> I checked, that 'nand_set_flash_node()' is called with 'nand@0' and i suppose > >>>>> that it is correct (as You mentioned below). But, 'nvmem_add_cells_from_of()' is called > >>>>> with parent: 'nfc@7800', then it iterates over its childs, e.g. 'nand@0' and thus i get such > >>>>> situation. I guess, that 'nvmem_add_cells_from_of()' must be called with 'nand@0' ? > >>>> > >>>> We recently had issues with nvmem parsing, but I believe a mainline > >>>> kernel should now be perfectly working on this regard. What version of > >>>> the Linux kernel are you using? > >>> > >>> My current version is: > >>> > >>> VERSION = 6 > >>> PATCHLEVEL = 2 > >>> SUBLEVEL = 0 > >>> EXTRAVERSION = -rc8 > >>> > >>> Fix was in drivers/nvmem/* ? > >>> > >>> Thanks, Arseniy > >> > >> Upd: I resolved problem in the following way: > >> > >> nand@0 { > >> reg = <0>;//chip select > >> > > partitions { > > compatible = ... > > > >> otp@0 { > >> #address-cells = <2>; > >> #size-cells = <0>; > > > > #address/size-cells is not needed here > > > >> compatible = "user-otp"; > >> reg = <A B>; > >> }; > >> otp@1 { > >> #address-cells = <2>; > >> #size-cells = <0>; > > > > Ditto > > > >> compatible = "factory-otp"; > >> reg = <C D>; > >> }; > > > > }; > > > >> }; > >> > >> Now nvmem subsystem parses 'otp@0' and 'otp@1' and error is gone. 'compatible' values are > >> the same as in drivers/mtd/mtdcore.c:mtd_otp_nvmem_add(). 'reg' in 'nand@0' is used as > >> chip select as supposed. > > > > I don't fully get it. The parsing on the nvmem side should not fail if > > there is no subpartition/otp-region defined. Can you confirm an empty > > NAND device node works? Because your last e-mail suggested the opposite. > > Ok, so i'll describe what happens in my case. Let's NAND node be like this (IIUC this is > considered as empty NAND device): > > mtd_nand: nfc@7800 { > compatible = "amlogic,meson-axg-nfc"; > ... > nand@0 { > reg = <0>; > }; > } > > I see, that > > 1) 'mtd_otp_nvmem_add()' calls 'mtd_otp_nvmem_register()' twice for two types of > OTP memory "user-otp" and "factory-otp". Let's take a look only on "user-otp". > 2) 'mtd_otp_nvmem_register()' tries to lookup for node in 'nand@0' which is compatible with > "user-otp" and then passes found (or not found, e.g. NULL) node to 'nvmem_register()'. > 3) 'nvmem_register()' uses this node iterating over its childs and searching value "reg" in > each child. If "user-otp" node is not found in 2), 'nvmem_register()' uses node 'nfc@7800' > also looking for "reg" value in each of its child. In this case it found "reg" in 'nand@0' > and fails. > > Now, if i add "compatible = "user-otp";" to 'nand@0', in step 2) search will be successful, > and "reg" value will be used from this new node (or we remove "reg" from it - nothing happens > as You wrote). So, problem is that nvmem tries to parse node with invalid "reg" value. > > Also I see, that 'nvmem_register()' is called earlier in 'mtd_nvmem_add()', but with no effect. > I think, that it is not related with enabled OTP feature. > > Thanks, Arseniy
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