Am Mittwoch, den 14.11.2012, 19:15 +0000 schrieb Grant Likely: > On Thu, 18 Oct 2012 16:27:33 +0200, Philipp Zabel <p.za...@pengutronix.de> > wrote: > > From: Matt Porter <mpor...@ti.com> > > > > Adds support for setting the genalloc pool's minimum allocation > > order via DT or platform data. The allocation order is optional > > for both the DT property and platform data case. If it is not > > present then the order defaults to PAGE_SHIFT to preserve the > > current behavior. > > > > Signed-off-by: Matt Porter <mpor...@ti.com> > > Signed-off-by: Philipp Zabel <p.za...@pengutronix.de> > > --- > > Documentation/devicetree/bindings/misc/sram.txt | 12 ++++++++++- > > drivers/misc/sram.c | 14 ++++++++++++- > > include/linux/platform_data/sram.h | 25 > > +++++++++++++++++++++++ > > 3 files changed, 49 insertions(+), 2 deletions(-) > > create mode 100644 include/linux/platform_data/sram.h > > > > diff --git a/Documentation/devicetree/bindings/misc/sram.txt > > b/Documentation/devicetree/bindings/misc/sram.txt > > index b64136c..b1705ec 100644 > > --- a/Documentation/devicetree/bindings/misc/sram.txt > > +++ b/Documentation/devicetree/bindings/misc/sram.txt > > @@ -8,10 +8,20 @@ Required properties: > > > > - reg : SRAM iomem address range > > > > -Example: > > +Optional properties: > > + > > +- alloc-order : Minimum allocation order for the SRAM pool > > Looks okay, but I think the property name is confusing. I for one had > no idea what 'order' would be and why it was important. I had to read > the code to figure it out. > > It does raise the question though of what is this binding actually > for? Does it reflect a limitation of the SRAM? or of the hardware using > the SRAM? Or is it an optimization? How do you expect to use it?
If I am not mistaken, it is about the expected use case. A driver allocating many small buffers would quickly fill small SRAMs if the allocations were of PAGE_SIZE granularity. I wonder if a common allocation size (say, 512 bytes instead of PAGE_SIZE) can be found that every prospective user could be reasonably happy with? > Assuming it is appropriate to put into the device tree, I'd suggest a > different name. Instead of 'order', how about 'sram-alloc-align' (in > address bits) or 'sram-alloc-min-size' (in bytes). A size in bytes would be the most obvious to me, although that allows to enter values that are not a power of two. regards Philipp -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
