Merge branch 'devicetree/next-reserved-mem' into devicetree/next

Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt

@@ -0,0 +1,133 @@
+*** Reserved memory regions ***
+
+Reserved memory is specified as a node under the /reserved-memory node.
+The operating system shall exclude reserved memory from normal usage
+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.
+
+Parameters for each memory region can be encoded into the device tree
+with the following nodes:
+
+/reserved-memory node
+---------------------
+#address-cells, #size-cells (required) - standard definition
+    - Should use the same values as the root node
+ranges (required) - standard definition
+    - Should be empty
+
+/reserved-memory/ child nodes
+-----------------------------
+Each child of the reserved-memory node specifies one or more regions of
+reserved memory. Each child node may either use a 'reg' property to
+specify a specific range of reserved memory, or a 'size' property with
+optional constraints to request a dynamically allocated block of memory.
+
+Following the generic-names recommended practice, node names should
+reflect the purpose of the node (ie. "framebuffer" or "dma-pool"). Unit
+address (@<address>) should be appended to the name if the node is a
+static allocation.
+
+Properties:
+Requires either a) or b) below.
+a) static allocation
+   reg (required) - standard definition
+b) dynamic allocation
+   size (required) - length based on parent's #size-cells
+                   - Size in bytes of memory to reserve.
+   alignment (optional) - length based on parent's #size-cells
+                        - Address boundary for alignment of allocation.
+   alloc-ranges (optional) - prop-encoded-array (address, length pairs).
+                           - Specifies regions of memory that are
+                             acceptable to allocate from.
+
+If both reg and size are present, then the reg property takes precedence
+and size is ignored.
+
+Additional properties:
+compatible (optional) - standard definition
+    - may contain the following strings:
+        - shared-dma-pool: This indicates a region of memory meant to be
+          used as a shared pool of DMA buffers for a set of devices. It can
+          be used by an operating system to instanciate the necessary pool
+          management subsystem if necessary.
+        - vendor specific string in the form <vendor>,[<device>-]<usage>
+no-map (optional) - empty property
+    - Indicates the operating system must not create a virtual mapping
+      of the region as part of its standard mapping of system memory,
+      nor permit speculative access to it under any circumstances other
+      than under the control of the device driver using the region.
+reusable (optional) - empty property
+    - The operating system can use the memory in this region with the
+      limitation that the device driver(s) owning the region need to be
+      able to reclaim it back. Typically that means that the operating
+      system can use that region to store volatile or cached data that
+      can be otherwise regenerated or migrated elsewhere.
+
+Linux implementation note:
+- If a "linux,cma-default" property is present, then Linux will use the
+  region for the default pool of the contiguous memory allocator.
+
+Device node references to reserved memory
+-----------------------------------------
+Regions in the /reserved-memory node may be referenced by other device
+nodes by adding a memory-region property to the device node.
+
+memory-region (optional) - phandle, specifier pairs to children of /reserved-memory
+
+Example
+-------
+This example defines 3 contiguous regions are defined for Linux kernel:
+one default of all device drivers (named linux,cma@72000000 and 64MiB in size),
+one dedicated to the framebuffer device (named framebuffer@78000000, 8MiB), and
+one for multimedia processing (named multimedia-memory@77000000, 64MiB).
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	memory {
+		reg = <0x40000000 0x40000000>;
+	};
+
+	reserved-memory {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges;
+
+		/* global autoconfigured region for contiguous allocations */
+		linux,cma {
+			compatible = "shared-dma-pool";
+			reusable;
+			size = <0x4000000>;
+			alignment = <0x2000>;
+			linux,cma-default;
+		};
+
+		display_reserved: framebuffer@78000000 {
+			reg = <0x78000000 0x800000>;
+		};
+
+		multimedia_reserved: multimedia@77000000 {
+			compatible = "acme,multimedia-memory";
+			reg = <0x77000000 0x4000000>;
+		};
+	};
+
+	/* ... */
+
+	fb0: video@12300000 {
+		memory-region = <&display_reserved>;
+		/* ... */
+	};
+
+	scaler: scaler@12500000 {
+		memory-region = <&multimedia_reserved>;
+		/* ... */
+	};
+
+	codec: codec@12600000 {
+		memory-region = <&multimedia_reserved>;
+		/* ... */
+	};
+};

arch/arm/Kconfig

@@ -1918,6 +1918,7 @@ config USE_OF
 	select IRQ_DOMAIN
 	select OF
 	select OF_EARLY_FLATTREE
+	select OF_RESERVED_MEM
 	help
 	  Include support for flattened device tree machine descriptions.
 

arch/arm/mm/init.c

@@ -323,6 +323,8 @@ void __init arm_memblock_init(struct meminfo *mi,
 	if (mdesc->reserve)
 		mdesc->reserve();
 
+	early_init_fdt_scan_reserved_mem();
+
 	/*
 	 * reserve memory for DMA contigouos allocations,
 	 * must come from DMA area inside low memory

arch/arm64/Kconfig

@@ -43,6 +43,7 @@ config ARM64
 	select NO_BOOTMEM
 	select OF
 	select OF_EARLY_FLATTREE
+	select OF_RESERVED_MEM
 	select PERF_USE_VMALLOC
 	select POWER_RESET
 	select POWER_SUPPLY

arch/arm64/mm/init.c

@@ -160,6 +160,7 @@ void __init arm64_memblock_init(void)
 		memblock_reserve(base, size);
 	}
 
+	early_init_fdt_scan_reserved_mem();
 	dma_contiguous_reserve(0);
 
 	memblock_allow_resize();

arch/powerpc/Kconfig

@@ -90,6 +90,7 @@ config PPC
 	select BINFMT_ELF
 	select OF
 	select OF_EARLY_FLATTREE
+	select OF_RESERVED_MEM
 	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_DYNAMIC_FTRACE
 	select HAVE_FUNCTION_TRACER

arch/powerpc/kernel/prom.c

@@ -33,6 +33,7 @@
 #include <linux/irq.h>
 #include <linux/memblock.h>
 #include <linux/of.h>
+#include <linux/of_fdt.h>
 
 #include <asm/prom.h>
 #include <asm/rtas.h>
@@ -588,6 +589,8 @@ static void __init early_reserve_mem_dt(void)
 			memblock_reserve(base, size);
 		}
 	}
+
+	early_init_fdt_scan_reserved_mem();
 }
 
 static void __init early_reserve_mem(void)

drivers/of/Kconfig

@@ -71,4 +71,10 @@ config OF_MTD
 	depends on MTD
 	def_bool y
 
+config OF_RESERVED_MEM
+	depends on OF_EARLY_FLATTREE
+	bool
+	help
+	  Helpers to allow for reservation of memory regions
+
 endmenu # OF

drivers/of/Makefile

@@ -9,3 +9,4 @@ 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/fdt.c

@@ -15,6 +15,8 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
+#include <linux/of_reserved_mem.h>
+#include <linux/sizes.h>
 #include <linux/string.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
@@ -439,6 +441,129 @@ struct boot_param_header *initial_boot_params;
 
 #ifdef CONFIG_OF_EARLY_FLATTREE
 
+/**
+ * res_mem_reserve_reg() - reserve all memory described in 'reg' property
+ */
+static int __init __reserved_mem_reserve_reg(unsigned long node,
+					     const char *uname)
+{
+	int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
+	phys_addr_t base, size;
+	unsigned long len;
+	__be32 *prop;
+	int nomap, first = 1;
+
+	prop = of_get_flat_dt_prop(node, "reg", &len);
+	if (!prop)
+		return -ENOENT;
+
+	if (len && len % t_len != 0) {
+		pr_err("Reserved memory: invalid reg property in '%s', skipping node.\n",
+		       uname);
+		return -EINVAL;
+	}
+
+	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
+
+	while (len >= t_len) {
+		base = dt_mem_next_cell(dt_root_addr_cells, &prop);
+		size = dt_mem_next_cell(dt_root_size_cells, &prop);
+
+		if (base && size &&
+		    early_init_dt_reserve_memory_arch(base, size, nomap) == 0)
+			pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %ld MiB\n",
+				uname, &base, (unsigned long)size / SZ_1M);
+		else
+			pr_info("Reserved memory: failed to reserve memory for node '%s': base %pa, size %ld MiB\n",
+				uname, &base, (unsigned long)size / SZ_1M);
+
+		len -= t_len;
+		if (first) {
+			fdt_reserved_mem_save_node(node, uname, base, size);
+			first = 0;
+		}
+	}
+	return 0;
+}
+
+/**
+ * __reserved_mem_check_root() - check if #size-cells, #address-cells provided
+ * in /reserved-memory matches the values supported by the current implementation,
+ * also check if ranges property has been provided
+ */
+static int __reserved_mem_check_root(unsigned long node)
+{
+	__be32 *prop;
+
+	prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
+	if (!prop || be32_to_cpup(prop) != dt_root_size_cells)
+		return -EINVAL;
+
+	prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
+	if (!prop || be32_to_cpup(prop) != dt_root_addr_cells)
+		return -EINVAL;
+
+	prop = of_get_flat_dt_prop(node, "ranges", NULL);
+	if (!prop)
+		return -EINVAL;
+	return 0;
+}
+
+/**
+ * fdt_scan_reserved_mem() - scan a single FDT node for reserved memory
+ */
+static int __init __fdt_scan_reserved_mem(unsigned long node, const char *uname,
+					  int depth, void *data)
+{
+	static int found;
+	const char *status;
+	int err;
+
+	if (!found && depth == 1 && strcmp(uname, "reserved-memory") == 0) {
+		if (__reserved_mem_check_root(node) != 0) {
+			pr_err("Reserved memory: unsupported node format, ignoring\n");
+			/* break scan */
+			return 1;
+		}
+		found = 1;
+		/* scan next node */
+		return 0;
+	} else if (!found) {
+		/* scan next node */
+		return 0;
+	} else if (found && depth < 2) {
+		/* scanning of /reserved-memory has been finished */
+		return 1;
+	}
+
+	status = of_get_flat_dt_prop(node, "status", NULL);
+	if (status && strcmp(status, "okay") != 0 && strcmp(status, "ok") != 0)
+		return 0;
+
+	err = __reserved_mem_reserve_reg(node, uname);
+	if (err == -ENOENT && of_get_flat_dt_prop(node, "size", NULL))
+		fdt_reserved_mem_save_node(node, uname, 0, 0);
+
+	/* scan next node */
+	return 0;
+}
+
+/**
+ * early_init_fdt_scan_reserved_mem() - create reserved memory regions
+ *
+ * This function grabs memory from early allocator for device exclusive use
+ * defined in device tree structures. It should be called by arch specific code
+ * once the early allocator (i.e. memblock) has been fully activated.
+ */
+void __init early_init_fdt_scan_reserved_mem(void)
+{
+	if (!initial_boot_params)
+		return;
+
+	of_scan_flat_dt(__fdt_scan_reserved_mem, NULL);
+	fdt_init_reserved_mem();
+}
+
 /**
  * of_scan_flat_dt - scan flattened tree blob and call callback on each.
  * @it: callback function
@@ -856,6 +981,16 @@ void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
 	memblock_add(base, size);
 }
 
+int __init __weak early_init_dt_reserve_memory_arch(phys_addr_t base,
+					phys_addr_t size, bool nomap)
+{
+	if (memblock_is_region_reserved(base, size))
+		return -EBUSY;
+	if (nomap)
+		return memblock_remove(base, size);
+	return memblock_reserve(base, size);
+}
+
 /*
  * called from unflatten_device_tree() to bootstrap devicetree itself
  * Architectures can override this definition if memblock isn't used
@@ -864,6 +999,14 @@ void * __init __weak early_init_dt_alloc_memory_arch(u64 size, u64 align)
 {
 	return __va(memblock_alloc(size, align));
 }
+#else
+int __init __weak early_init_dt_reserve_memory_arch(phys_addr_t base,
+					phys_addr_t size, bool nomap)
+{
+	pr_err("Reserved memory not supported, ignoring range 0x%llx - 0x%llx%s\n",
+		  base, size, nomap ? " (nomap)" : "");
+	return -ENOSYS;
+}
 #endif
 
 bool __init early_init_dt_scan(void *params)