Thread (16 messages) flat view 16 messages, 4 authors, 2012-09-03

[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(-)
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