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Subject[PATCH v2 2/2] staging: ion: Add ion-physmem documentation
Date
Signed-off-by: Andrew Andrianov <andrew@ncrmnt.org>
---
Documentation/devicetree/bindings/ion,physmem.txt | 96 +++++++++++++++++++++
1 file changed, 96 insertions(+)
create mode 100644 Documentation/devicetree/bindings/ion,physmem.txt

diff --git a/Documentation/devicetree/bindings/ion,physmem.txt b/Documentation/devicetree/bindings/ion,physmem.txt
new file mode 100644
index 0000000..b83ae22
--- /dev/null
+++ b/Documentation/devicetree/bindings/ion,physmem.txt
@@ -0,0 +1,96 @@
+ION PhysMem Driver
+#include <dt-bindings/ion,physmem.h>
+
+
+ION PhysMem is a generic driver for ION Memory Manager that allows you to
+define ION Memory Manager heaps using device tree. This is mostly useful if
+your SoC has several 'special' regions (e.g. SRAM, dedicated memory banks,
+etc) that are present in the physical memory map and you want to add them to
+ION as heaps of memory.
+
+
+Examples:
+
+1. 256KiB On-chip SRAM used as ION DMA heap. reg range is treated as a physical
+ address range
+
+ ion_im0: ion@0x00100000 {
+ compatible = "ion,physmem";
+ reg = <0x00100000 0x40000>;
+ reg-names = "memory";
+ ion-heap-id = <2>;
+ ion-heap-type = <ION_HEAP_TYPE_DMA>;
+ ion-heap-align = <0x10>;
+ ion-heap-name = "IM0";
+ };
+
+2. The same, but using system DMA memory.
+
+ ion_dma: ion@0xdeadbeef {
+ compatible = "ion,physmem";
+ ion-heap-id = <2>;
+ ion-heap-type = <ION_HEAP_TYPE_DMA>;
+ ion-heap-align = <0x10>;
+ ion-heap-name = "SYSDMA";
+ };
+
+2. Carveout heap, 1MiB size, ion-physmem will alloc pages for it using
+ alloc_pages_exact(). reg range is used for specifying size only.
+
+ ion_crv: ion@deadbeef {
+ compatible = "ion,physmem";
+ reg = <0x00000000 0x100000>;
+ reg-names = "memory";
+ ion-heap-id = <3>;
+ ion-heap-type = <ION_HEAP_TYPE_CARVEOUT>;
+ ion-heap-align = <0x10>;
+ ion-heap-name = "carveout";
+ };
+
+3. Chunk heap. 1MiB size, ion-physmem will alloc pages for it using
+ alloc_pages_exact(). reg range is used for specifying size only.
+
+ ion_chunk: ion@0xdeadbeef {
+ compatible = "ion,physmem";
+ ion-heap-id = <2>;
+ ion-heap-type = <ION_HEAP_TYPE_CHUNK>;
+ ion-heap-align = <0x10>;
+ ion-heap-name = "chunky";
+ };
+
+
+4. vmalloc();
+
+ ion_chunk: ion@0xdeadbeef {
+ compatible = "ion,physmem";
+ ion-heap-id = <2>;
+ ion-heap-type = <ION_HEAP_TYPE_SYSTEM>;
+ ion-heap-align = <0x10>;
+ ion-heap-name = "sys";
+ };
+
+5. kmalloc();
+
+ ion_chunk: ion@0xdeadbeef {
+ compatible = "ion,physmem";
+ ion-heap-id = <2>;
+ ion-heap-type = <ION_HEAP_TYPE_SYSTEM_CONTIG>;
+ ion-heap-align = <0x10>;
+ ion-heap-name = "syscont";
+ };
+
+If the underlying heap relies on some physical device that needs clock
+gating, you can need to fill the clock field in. E.g.:
+
+
+ ion_im0: ion@0x00100000 {
+ compatible = "ion,physmem";
+ reg = <0x00100000 0x40000>;
+ reg-names = "memory";
+ ion-heap-id = <2>;
+ ion-heap-type = <ION_HEAP_TYPE_DMA>;
+ ion-heap-align = <0x10>;
+ ion-heap-name = "IM0";
+ clocks = <&oscillator_27m>;
+ clock-names = "clk_27m";
+ };
--
1.7.10.4


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