[PATCH v8 0/4] Add generic driver for on-chip SRAM

Philipp Zabel
2013-02-04T11:32:32Z

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 struct device pointer 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.

I changed the implementation in genalloc.c since v7. To avoid the global
pool list, a devres managed version of gen_pool_create is added, and
gen_pool_find_by_phys of the previous versions is replaced by dev_get_gen_pool,
that retrieves a gen_pool created with devm_gen_pool_create from the
corresponding device pointer. of_get_named_gen_pool is called unchanged.

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>;
};

Changes since v7:
- Removed the global pool list in genalloc. Instead, added a devres managed
version of gen_pool_create, replacing gen_pool_find_by_phys with
dev_get_gen_pool (and made of_get_named_gen_pool use that)
- In the coda driver, switched to dev_get_gen_pool and added a platform_data
struct to pass the SRAM device pointer (instead of using a second IO memory
resource). Added device tree binding documentation.

regards
Philipp

---
Documentation/devicetree/bindings/media/coda.txt | 30 ++++++
Documentation/devicetree/bindings/misc/sram.txt | 17 +++
arch/arm/boot/dts/imx53.dtsi | 5 +
arch/arm/boot/dts/imx6q.dtsi | 6 ++
drivers/media/platform/Kconfig | 1 -
drivers/media/platform/coda.c | 45 +++++---
drivers/misc/Kconfig | 9 ++
drivers/misc/Makefile | 1 +
drivers/misc/sram.c | 121 ++++++++++++++++++++++
include/linux/genalloc.h | 15 +++
include/linux/platform_data/coda.h | 18 ++++
lib/genalloc.c | 81 +++++++++++++++
12 files changed, 334 insertions(+), 15 deletions(-)