From: Philipp Zabel <p.zabel@pengutronix.de>
To: linux-kernel@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Grant Likely <grant.likely@secretlab.ca>,
Rob Herring <rob.herring@calxeda.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Shawn Guo <shawn.guo@linaro.org>,
Richard Zhao <richard.zhao@freescale.com>,
Huang Shijie <shijie8@gmail.com>,
Dong Aisheng <dong.aisheng@linaro.org>,
Matt Porter <mporter@ti.com>,
Fabio Estevam <fabio.estevam@freescale.com>,
Javier Martin <javier.martin@vista-silicon.com>,
kernel@pengutronix.de, devicetree-discuss@lists.ozlabs.org
Subject: [PATCH v7 0/4] Add generic driver for on-chip SRAM
Date: Fri, 23 Nov 2012 15:24:11 +0100 [thread overview]
Message-ID: <1353680655-21624-1-git-send-email-p.zabel@pengutronix.de> (raw)
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.
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.
Changes since v6:
- Reduced the hard coded allocation granularity to 32 bytes.
regards
Philipp
---
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 | 3 +-
drivers/media/platform/coda.c | 47 ++++++---
drivers/misc/Kconfig | 9 ++
drivers/misc/Makefile | 1 +
drivers/misc/sram.c | 121 +++++++++++++++++++++++
include/linux/genalloc.h | 14 +++
lib/genalloc.c | 67 +++++++++++++
10 files changed, 274 insertions(+), 16 deletions(-)
next reply other threads:[~2012-11-23 14:24 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-23 14:24 Philipp Zabel [this message]
2012-11-23 14:24 ` [PATCH v7 1/4] genalloc: add a global pool list, allow to find pools by phys address Philipp Zabel
2012-11-23 14:24 ` [PATCH v7 2/4] misc: Generic on-chip SRAM allocation driver Philipp Zabel
2012-11-23 14:24 ` [PATCH v7 3/4] media: coda: use genalloc API Philipp Zabel
2012-11-23 14:24 ` [PATCH v7 4/4] ARM: dts: add sram for imx53 and imx6q Philipp Zabel
2012-12-04 8:53 ` [PATCH v7 0/4] Add generic driver for on-chip SRAM Philipp Zabel
2012-12-04 16:19 ` Greg Kroah-Hartman
2012-12-04 16:55 ` Philipp Zabel
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