[PATCH] clkdev: add support to lookup for early platform device

Jean-Christophe PLAGNIOL-VILLARD plagnioj at jcrosoft.com
Wed Apr 27 23:17:04 EDT 2011


On 12:08 Thu 28 Apr     , Paul Mundt wrote:
> On Thu, Apr 28, 2011 at 04:45:59AM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote:
> > On 11:09 Thu 28 Apr     , Paul Mundt wrote:
> > > On Wed, Apr 27, 2011 at 05:00:57PM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote:
> > > > On 12:47 Wed 27 Apr     , Jean-Christophe PLAGNIOL-VILLARD wrote:
> > > > > On 12:31 Wed 27 Apr     , Jean-Christophe PLAGNIOL-VILLARD wrote:
> > > > > > On 09:42 Wed 27 Apr     , Russell King - ARM Linux wrote:
> > > > > > > On Wed, Apr 20, 2011 at 04:05:14PM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote:
> > > > > > > > early platform device may do not have a device name as the slab is not yet
> > > > > > > > available. So to search a clock base on the dev_id we need to search first the
> > > > > > > > device base name and then the id
> > > > > > > 
> > > > > > > I really don't like this.  IDs are platform device specific, and this is
> > > > > > > a platform devince independent layer.
> > > > > > > 
> > > > > > > If you want to do this, then add a platform_device_clk_get() call, which
> > > > > > > takes the platform device and connection id.  Uses the platform device
> > > > > > > infrastructure to format the device name, and use clk_get_sys() to look
> > > > > > > up the device/connection id from that.
> > > > > > I do not want to alloc a string in the clkdev
> > > > > > but if you prefer
> > > > > I check we can not do so
> > > > > if slab is not available we can not use kmalloc
> > > > > 
> > > > > so we can not generate the dev.init_name
> > > > I check also we can not use the bootmem as it's too early in the init
> > > > so allocate the dev_id is not possible
> > > > 
> > > > use a satic buffer I'm not so happy about it
> > > > the only other solution is this one
> > > > 
> > > Are you willfully ignoring the init_name handling in
> > > early_platform_driver_probe_id() or something?
> > > 
> > > See a636ee7fb35b731ba2b331f6294e809bb6be09c8 for example.
> > excatly but the issue is that the slab is not availlable yet
> > see 06fe53beb636294587d8e94ef83c06cef07c21fd
> > so init_name is still NULL :(
> > 
> This is a non-argument until you demonstrate a use case where we have a
> reasonable expectation for the clock framework to be available and the
> slab allocator not.
> 
> If you're thinking about the SH earlyprintk case then I suggest you look
> at the sh-sci driver to see how we presently deal with the situation
> there.
the sh-sci driver expect the clock will enable for him
which did IIRC Magnus on sh-mobile
I do not want to do so

I've unfortunatly on at91 I use the early device during the map_io

so the slab is available and bootmem either

Best Regards,
J.



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