Re: [PATCH v7 0/4] Add generic driver for on-chip SRAM

From: Philipp Zabel
Date: Tue Dec 04 2012 - 11:55:30 EST


On Tue, 2012-12-04 at 08:19 -0800, Greg Kroah-Hartman wrote:
> On Tue, Dec 04, 2012 at 09:53:38AM +0100, Philipp Zabel wrote:
> > Hi,
> >
> > On Fri, 2012-11-23 at 15:24 +0100, Philipp Zabel wrote:
> > > These patches add support to configure on-chip SRAM via device-tree
> > > node or platform data and to obtain the resulting genalloc pool from
> > > the physical address or a phandle pointing at the device tree node.
> > > This allows drivers to allocate SRAM with the genalloc API without
> > > hard-coding the genalloc pool pointer.
> >
> > are there any further comments on this series?
> >
> > > The on-chip SRAM on i.MX53 and i.MX6q can be registered via device tree
> > > and changed to use the simple generic SRAM driver:
> > >
> > > ocram: ocram@00900000 {
> > > compatible = "fsl,imx-ocram", "sram";
> > > reg = <0x00900000 0x3f000>;
> > > };
> > >
> > > A driver that needs to allocate SRAM buffers, like the video processing
> > > unit on i.MX53, can retrieve the genalloc pool from a phandle in the
> > > device tree using of_get_named_gen_pool(node, "iram", 0) from patch 1:
> > >
> > > vpu@63ff4000 {
> > > /* ... */
> > > iram = <&ocram>;
> > > };
> > >
> > > The allocation granularity is hard-coded to 32 bytes for now,
> > > until a way to configure it can be agreed upon. There is overhead
> > > for bigger SRAMs, where only a much coarser allocation granularity
> > > is needed: At 32 bytes minimum allocation size, a 256 KiB SRAM
> > > needs a 1 KiB bitmap to track allocations.
> > >
> > > Once everybody is ok with it, could the first two patches be merged
> > > through the char-misc tree? I'll resend the i.MX and coda patches to
> > > the respective lists afterwards.
> >
> > Arnd, Greg, would you take the first patch "genalloc: add a global pool
> > list, allow to find pools by phys address" into the char-misc tree if
> > there are no vetoes? Or should I try and get it merged separately,
> > first?
>
> It's too late for anything new for 3.8, so how about resending this all
> after 3.8-rc1 is out and we can take it from there?

Ok, I'll do that.

thanks
Philipp

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