Commit 34ec4de4 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'devicetree-for-linus' of git://git.secretlab.ca/git/linux 

Pull device tree fixes and reverts from Grant Likely:
 "One bug fix and three reverts.  The reverts back out the slightly
  controversial feeding the entire device tree into the random pool and
  the reserved-memory binding which isn't fully baked yet.  Expect the
  reserved-memory patches at least to resurface for v3.13.

  The bug fixes removes a scary but harmless warning on SPARC that was
  introduced in the v3.12 merge window.  v3.13 will contain a proper fix
  that makes the new code work on SPARC.

  On the plus side, the diffstat looks *awesome*.  I love removing lines
  of code"

* tag 'devicetree-for-linus' of git://git.secretlab.ca/git/linux:
  Revert "drivers: of: add initialization code for dma reserved memory"
  Revert "ARM: init: add support for reserved memory defined by device tree"
  Revert "of: Feed entire flattened device tree into the random pool"
  of: fix unnecessary warning on missing /cpus node
parents ba0a062e 1931ee14

Documentation/devicetree/bindings/memory.txt

deleted100644 → 0
+0 −168
Original line number Diff line number Diff line 
*** Memory binding ***



The /memory node provides basic information about the address and size

of the physical memory. This node is usually filled or updated by the

bootloader, depending on the actual memory configuration of the given

hardware.



The memory layout is described by the following node:



/ {

	#address-cells = <(n)>;

	#size-cells = <(m)>;

	memory {

		device_type = "memory";

		reg =  <(baseaddr1) (size1)

			(baseaddr2) (size2)

			...

			(baseaddrN) (sizeN)>;

	};

	...

};



A memory node follows the typical device tree rules for "reg" property:

n:		number of cells used to store base address value

m:		number of cells used to store size value

baseaddrX:	defines a base address of the defined memory bank

sizeX:		the size of the defined memory bank





More than one memory bank can be defined.





*** Reserved memory regions ***



In /memory/reserved-memory node one can create child nodes describing

particular reserved (excluded from normal use) memory regions. Such

memory regions are usually designed for the special usage by various

device drivers. A good example are contiguous memory allocations or

memory sharing with other operating system on the same hardware board.

Those special memory regions might depend on the board configuration and

devices used on the target system.



Parameters for each memory region can be encoded into the device tree

with the following convention:



[(label):] (name) {

	compatible = "linux,contiguous-memory-region", "reserved-memory-region";

	reg = <(address) (size)>;

	(linux,default-contiguous-region);

};



compatible:	one or more of:

	- "linux,contiguous-memory-region" - enables binding of this

	  region to Contiguous Memory Allocator (special region for

	  contiguous memory allocations, shared with movable system

	  memory, Linux kernel-specific).

	- "reserved-memory-region" - compatibility is defined, given

	  region is assigned for exclusive usage for by the respective

	  devices.



reg:	standard property defining the base address and size of

	the memory region



linux,default-contiguous-region: property indicating that the region

	is the default region for all contiguous memory

	allocations, Linux specific (optional)



It is optional to specify the base address, so if one wants to use

autoconfiguration of the base address, '0' can be specified as a base

address in the 'reg' property.



The /memory/reserved-memory node must contain the same #address-cells

and #size-cells value as the root node.





*** Device node's properties ***



Once regions in the /memory/reserved-memory node have been defined, they

may be referenced by other device nodes. Bindings that wish to reference

memory regions should explicitly document their use of the following

property:



memory-region = <&phandle_to_defined_region>;



This property indicates that the device driver should use the memory

region pointed by the given phandle.





*** Example ***



This example defines a memory consisting of 4 memory banks. 3 contiguous

regions are defined for Linux kernel, one default of all device drivers

(named contig_mem, placed at 0x72000000, 64MiB), one dedicated to the

framebuffer device (labelled display_mem, placed at 0x78000000, 8MiB)

and one for multimedia processing (labelled multimedia_mem, placed at

0x77000000, 64MiB). 'display_mem' region is then assigned to fb@12300000

device for DMA memory allocations (Linux kernel drivers will use CMA is

available or dma-exclusive usage otherwise). 'multimedia_mem' is

assigned to scaler@12500000 and codec@12600000 devices for contiguous

memory allocations when CMA driver is enabled.



The reason for creating a separate region for framebuffer device is to

match the framebuffer base address to the one configured by bootloader,

so once Linux kernel drivers starts no glitches on the displayed boot

logo appears. Scaller and codec drivers should share the memory

allocations.



/ {

	#address-cells = <1>;

	#size-cells = <1>;



	/* ... */



	memory {

		reg =  <0x40000000 0x10000000

			0x50000000 0x10000000

			0x60000000 0x10000000

			0x70000000 0x10000000>;



		reserved-memory {

			#address-cells = <1>;

			#size-cells = <1>;



			/*

			 * global autoconfigured region for contiguous allocations

			 * (used only with Contiguous Memory Allocator)

			 */

			contig_region@0 {

				compatible = "linux,contiguous-memory-region";

				reg = <0x0 0x4000000>;

				linux,default-contiguous-region;

			};



			/*

			 * special region for framebuffer

			 */

			display_region: region@78000000 {

				compatible = "linux,contiguous-memory-region", "reserved-memory-region";

				reg = <0x78000000 0x800000>;

			};



			/*

			 * special region for multimedia processing devices

			 */

			multimedia_region: region@77000000 {

				compatible = "linux,contiguous-memory-region";

				reg = <0x77000000 0x4000000>;

			};

		};

	};



	/* ... */



	fb0: fb@12300000 {

		status = "okay";

		memory-region = <&display_region>;

	};



	scaler: scaler@12500000 {

		status = "okay";

		memory-region = <&multimedia_region>;

	};



	codec: codec@12600000 {

		status = "okay";

		memory-region = <&multimedia_region>;

	};

};

arch/arm/mm/init.c

+0 −3
Original line number Diff line number Diff line
@@ -17,7 +17,6 @@ 
#include <linux/nodemask.h>

#include <linux/initrd.h>

#include <linux/of_fdt.h>

#include <linux/of_reserved_mem.h>

#include <linux/highmem.h>

#include <linux/gfp.h>

#include <linux/memblock.h>
@@ -379,8 +378,6 @@ void __init arm_memblock_init(struct meminfo *mi, 
	if (mdesc->reserve)

		mdesc->reserve();



	early_init_dt_scan_reserved_mem();



	/*

	 * reserve memory for DMA contigouos allocations,

	 * must come from DMA area inside low memory

drivers/of/Kconfig

+0 −6
Original line number Diff line number Diff line
@@ -74,10 +74,4 @@ config OF_MTD 
	depends on MTD

	def_bool y



config OF_RESERVED_MEM

	depends on OF_FLATTREE && (DMA_CMA || (HAVE_GENERIC_DMA_COHERENT && HAVE_MEMBLOCK))

	def_bool y

	help

	  Initialization code for DMA reserved memory



endmenu # OF

drivers/of/Makefile

+0 −1
Original line number Diff line number Diff line
@@ -9,4 +9,3 @@ obj-$(CONFIG_OF_MDIO) += of_mdio.o 
obj-$(CONFIG_OF_PCI)	+= of_pci.o

obj-$(CONFIG_OF_PCI_IRQ)  += of_pci_irq.o

obj-$(CONFIG_OF_MTD)	+= of_mtd.o
 
obj-$(CONFIG_OF_RESERVED_MEM) += of_reserved_mem.o

drivers/of/base.c

+1 −3
Original line number Diff line number Diff line
@@ -303,10 +303,8 @@ struct device_node *of_get_cpu_node(int cpu, unsigned int *thread) 
	struct device_node *cpun, *cpus;



	cpus = of_find_node_by_path("/cpus");

	if (!cpus) {

		pr_warn("Missing cpus node, bailing out\n");

	if (!cpus)

		return NULL;

	}



	for_each_child_of_node(cpus, cpun) {

		if (of_node_cmp(cpun->type, "cpu"))

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