Re: [PATCH v7 0/4] Add generic driver for on-chip SRAM
From: Philipp Zabel <p.zabel@pengutronix.de>
Date: 2012-12-04 16:55:41
Also in:
lkml
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:quoted
Hi, On Fri, 2012-11-23 at 15:24 +0100, Philipp Zabel wrote:quoted
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?quoted
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