Messages in this thread | | | From | Marek Vasut <> | Subject | Re: [PATCH 04/11] mtd: ofpart: do not fail probe when no partitions exist | Date | Thu, 4 Jun 2015 17:28:50 +0200 |
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On Thursday, June 04, 2015 at 06:54:00 AM, Michal Suchanek wrote: > On 4 June 2015 at 00:58, Marek Vasut <marex@denx.de> wrote: > > On Wednesday, June 03, 2015 at 11:26:40 PM, Michal Suchanek wrote: > >> On Exynos it is necessary to set SPI controller parameters that apply to > >> a SPI slave in a DT subnode of the slave device. The ofpart code returns > >> an error when there are subnodes of the SPI flash but no partitions are > >> found. Change this condition to a warning so that flash without > >> partitions can be accessed on Exynos. > > > > I have to admit the rationale for this patch is not very clear to me, > > sorry. Can you please explain this a bit more ? > > This is how the DT entry for SPI slave looks with s3c64xx: > flash: m25p80@0 { > #address-cells = <1>; > #size-cells = <1>; > compatible = "jedec,spi-nor"; > reg = <0>; > spi-max-frequency = <40000000>; > linux,max_tx_len = <65536>;
SIDENOTE: I thought this was actually added by your patch #8 in this series. The underscores in the name of the property are not really consistent with the rest of the names.
> m25p,fast-read; > controller-data { > samsung,spi-feedback-delay = <0>; > }; > }; > > this is example of flash partitions: > flash@0 { > #address-cells = <1>; > #size-cells = <1>; > > partition@0 { > label = "u-boot"; > reg = <0x0000000 0x100000>; > read-only; > }; > > uimage@100000 { > reg = <0x0100000 0x200000>; > }; > }; > > The parser ignores any flash without subnodes and returns 0 (no > partititon). When there is a subnode it assumes the flash is > partitioned and tries to parse the subnodes as partitions. When there > are subnodes and none parses as partition an error is returned. As > shown above it is valid to have subnodes on unpartitioned flash. > > When an error is returned from a partition parser the mtdpart code > passes on this error to the flash probe function and the proble of the > flash fails.
What does /proc/mtd tell you when you have no partitions defined in the DT ? It should provide you with the entire MTD device and the code shouldn't even try to parse any OF partitions, since you don't have any.
Best regards, Marek Vasut
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