[PATCH v1] mtd: core: add sysfs nodes for querying the flash name and id

Zhuohao Lee zhuohao at chromium.org
Tue Apr 2 06:03:28 PDT 2019


Boris, Thanks for your comment.
But I can't find the related stuff (or i got the wrong way). Is that
feature merged?
Could you please point out the commit? I can make the change base on it.

On Tue, Apr 2, 2019 at 8:01 PM Boris Brezillon
<boris.brezillon at collabora.com> wrote:
>
> On Tue, 2 Apr 2019 19:06:37 +0800
> Zhuohao Lee <zhuohao at chromium.org> wrote:
>
> > On Tue, Apr 2, 2019 at 4:26 PM Vignesh Raghavendra <vigneshr at ti.com> wrote:
> > >
> > >
> > >
> > > On 02/04/19 1:26 PM, Boris Brezillon wrote:
> > > > On Tue, 2 Apr 2019 15:39:54 +0800
> > > > Zhuohao Lee <zhuohao at chromium.org> wrote:
> > > >
> > > >> Thanks Boris for the comment. Please take a look the reply at below.
> > > >>
> > > >> On Mon, Apr 1, 2019 at 5:27 PM Boris Brezillon
> > > >> <boris.brezillon at collabora.com> wrote:
> > > >>>
> > > >>> On Thu, 28 Mar 2019 12:59:10 +0800
> > > >>> Zhuohao Lee <zhuohao at chromium.org> wrote:
> > > >>>
> > > >>>> Currently, we don't have sysfs nodes for querying the underlying flash
> > > >>>> name and flash id. This information is important especially when we
> > > >>>> want to know the flash detail of the defective system. In order to
> > > >>>> support the query, we add two pointers (*flashname, *id) into the
> > > >>>> mtd_info structure and create two sysfs nodes (flashname, id). This
> > > >>>> patch is modified based on the SPI-NOR flash system as we only have
> > > >>>> that system now. But the idea should be applied to the other flash
> > > >>>> driver like NAND flash.
> > > >>>>
> > > >>>> The output of new sysfs nodes on my device are:
> > > >>>> cat /sys/devices/platform/soc/11010000.spi/spi_master/spi1/spi1.0/mtd/mtd0/flashname
> > > >>>> w25q64dw
> > > >>>> cat /sys/devices/platform/soc/11010000.spi/spi_master/spi1/spi1.0/mtd/mtd0/id
> > > >>>> ef6017
> > > >>>
> > > >>> I'm not sure I like the idea of exposing this kind of info through
> > > >>> sysfs as it then makes part of the ABI. Did you consider exposing that
> > > >>> through debugfs?
> > > >>
> > > >> Yes, i did consider the debugfs. I think the debugfs is depended on
> > > >> CONFIG_DEBUG_FS.
> > > >> If removing that config, the partname and partid will be lost. So, i
> > > >> proposed to use
> > > >> sysfs.
> > > >
> > > > Then just enable debugfs if you need this information :P.
> > My original intention is adding the new sysfs nodes (i.e partname and
> > partid) into the common place like mtdcore.c
> > so that the userspace program can just read the common sysfs nodes.
> > So far, what i can contribute is for the spi-nor but if the other
> > flash drivers, like nand-flash, can also support
> > the partname and partid query, then, we can have common sysfs nodes to
> > query the underlying device info.
> > Compare to the debugfs, i think different drivers may have different
> > name for the partname and partid.
>
> We've recently unified how MTD related stuff are exposed through
> debugfs and you can now have generic MTD fields exposed there.



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