aboutsummaryrefslogtreecommitdiff
path: root/Documentation/devicetree
diff options
context:
space:
mode:
authorPhilipp Zabel <p.zabel@pengutronix.de>2013-04-29 16:17:12 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-04-29 18:28:13 -0700
commit4984c6f5e56c3e68922fd979347ba7aff385783b (patch)
tree7931e0e6dbb71d837a24638cebc62a5dbb38798b /Documentation/devicetree
parent9375db07adeaeea5f5ea7ca0463a8b371d71ddbb (diff)
downloadlinux-4984c6f5e56c3e68922fd979347ba7aff385783b.tar.gz
misc: generic on-chip SRAM allocation driver
This driver requests and remaps a memory region as configured in the device tree. It serves memory from this region via the genalloc API. It optionally enables the SRAM clock. Other drivers can retrieve the genalloc pool from a phandle pointing to this drivers' device node in the device tree. The allocation granularity is hard-coded to 32 bytes for now, to make the SRAM driver useful for the 6502 remoteproc driver. 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. [akpm@linux-foundation.org: fix Kconfig text, make sram_init static] Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> Acked-by: Grant Likely <grant.likely@secretlab.ca> Tested-by: Michal Simek <monstr@monstr.eu> Cc: Dong Aisheng <dong.aisheng@linaro.org> Cc: Fabio Estevam <fabio.estevam@freescale.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Huang Shijie <shijie8@gmail.com> Cc: Javier Martin <javier.martin@vista-silicon.com> Cc: Matt Porter <mporter@ti.com> Cc: Michal Simek <monstr@monstr.eu> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Rob Herring <rob.herring@calxeda.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/devicetree')
-rw-r--r--Documentation/devicetree/bindings/misc/sram.txt16
1 files changed, 16 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/misc/sram.txt b/Documentation/devicetree/bindings/misc/sram.txt
new file mode 100644
index 00000000000..4d0a00e453a
--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/sram.txt
@@ -0,0 +1,16 @@
+Generic on-chip SRAM
+
+Simple IO memory regions to be managed by the genalloc API.
+
+Required properties:
+
+- compatible : mmio-sram
+
+- reg : SRAM iomem address range
+
+Example:
+
+sram: sram@5c000000 {
+ compatible = "mmio-sram";
+ reg = <0x5c000000 0x40000>; /* 256 KiB SRAM at address 0x5c000000 */
+};