[PATCH v2 0/9] Add device tree support for on-chip SRAM
From: Shawn Guo <hidden>
Date: 2012-09-03 01:53:56
Also in:
linux-devicetree, lkml
I do not understand the point of introducing those imx patches, 1 ~ 4 and 7, 8. They are all unnecessary churns to me. IMO, 4 patches are enough. * genalloc: add a global pool list, allow to find pools by phys address * misc: Generic on-chip SRAM allocation driver * ARM i.MX: remove IRAM_ALLOC facility * ARM: dts: add sram for imx53 and imx6q Regards, Shawn On Fri, Aug 31, 2012 at 11:26:55AM +0200, Philipp Zabel wrote:
These patches add support to configure on-chip SRAM via device-tree
node and to obtain the resulting genalloc pool from a phandle pointing
at the node.
This allows drivers to allocate SRAM with the genalloc API without
hard-coding the genalloc pool address.
The on-chip SRAM on i.MX53 and i.MX6q is registered via device tree and
changed to use the simple generic SRAM driver:
ocram: ocram at 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 5:
vpu at 63ff4000 {
/* ... */
iram = <&ocram>;
};
Changes since v1:
- Added a generic SRAM driver in drivers/misc that does nothing but
request/ioremap its given memory region and serve it via the genalloc
API.
- Renamed the i.MX device tree nodes from "iram" to "ocram".
regards
Philipp
---
arch/arm/boot/dts/imx53.dtsi | 5 ++
arch/arm/boot/dts/imx6q.dtsi | 5 ++
arch/arm/plat-mxc/Kconfig | 4 --
arch/arm/plat-mxc/Makefile | 1 -
arch/arm/plat-mxc/include/mach/iram.h | 41 -------------
arch/arm/plat-mxc/iram_alloc.c | 73 -----------------------
drivers/misc/Kconfig | 8 +++
drivers/misc/Makefile | 1 +
drivers/misc/sram.c | 105 +++++++++++++++++++++++++++++++++
include/linux/genalloc.h | 14 +++++
lib/genalloc.c | 77 ++++++++++++++++++++++++
11 files changed, 215 insertions(+), 119 deletions(-)