diff options
| -rw-r--r-- | Documentation/devicetree/bindings/memory.txt | 168 | ||||
| -rw-r--r-- | drivers/of/Kconfig | 6 | ||||
| -rw-r--r-- | drivers/of/Makefile | 1 | ||||
| -rw-r--r-- | drivers/of/of_reserved_mem.c | 175 | ||||
| -rw-r--r-- | drivers/of/platform.c | 4 | ||||
| -rw-r--r-- | include/linux/of_reserved_mem.h | 14 |
6 files changed, 368 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/memory.txt b/Documentation/devicetree/bindings/memory.txt new file mode 100644 index 0000000..eb24693 --- /dev/null +++ b/Documentation/devicetree/bindings/memory.txt @@ -0,0 +1,168 @@ +*** 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>; + }; +}; diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig index 80e5c13..7309651 100644 --- a/drivers/of/Kconfig +++ b/drivers/of/Kconfig @@ -80,4 +80,10 @@ 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 diff --git a/drivers/of/Makefile b/drivers/of/Makefile index 1f9c0c4..e7e3322 100644 --- a/drivers/of/Makefile +++ b/drivers/of/Makefile @@ -10,3 +10,4 @@ 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 diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c new file mode 100644 index 0000000..a754b84 --- /dev/null +++ b/drivers/of/of_reserved_mem.c @@ -0,0 +1,175 @@ +/* + * Device tree based initialization code for reserved memory. + * + * Copyright (c) 2013 Samsung Electronics Co., Ltd. + * http://www.samsung.com + * Author: Marek Szyprowski <m.szyprowski@samsung.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License or (at your optional) any later version of the license. + */ + +#include <asm/dma-contiguous.h> + +#include <linux/memblock.h> +#include <linux/err.h> +#include <linux/of.h> +#include <linux/of_fdt.h> +#include <linux/of_platform.h> +#include <linux/mm.h> +#include <linux/sizes.h> +#include <linux/mm_types.h> +#include <linux/dma-contiguous.h> +#include <linux/dma-mapping.h> +#include <linux/of_reserved_mem.h> + +#define MAX_RESERVED_REGIONS 16 +struct reserved_mem { + phys_addr_t base; + unsigned long size; + struct cma *cma; + char name[32]; +}; +static struct reserved_mem reserved_mem[MAX_RESERVED_REGIONS]; +static int reserved_mem_count; + +static int __init fdt_scan_reserved_mem(unsigned long node, const char *uname, + int depth, void *data) +{ + struct reserved_mem *rmem = &reserved_mem[reserved_mem_count]; + phys_addr_t base, size; + int is_cma, is_reserved; + unsigned long len; + const char *status; + __be32 *prop; + + is_cma = IS_ENABLED(CONFIG_DMA_CMA) && + of_flat_dt_is_compatible(node, "linux,contiguous-memory-region"); + is_reserved = of_flat_dt_is_compatible(node, "reserved-memory-region"); + + if (!is_reserved && !is_cma) { + /* ignore node and scan next one */ + return 0; + } + + status = of_get_flat_dt_prop(node, "status", &len); + if (status && strcmp(status, "okay") != 0) { + /* ignore disabled node nad scan next one */ + return 0; + } + + prop = of_get_flat_dt_prop(node, "reg", &len); + if (!prop || (len < (dt_root_size_cells + dt_root_addr_cells) * + sizeof(__be32))) { + pr_err("Reserved mem: node %s, incorrect \"reg\" property\n", + uname); + /* ignore node and scan next one */ + return 0; + } + base = dt_mem_next_cell(dt_root_addr_cells, &prop); + size = dt_mem_next_cell(dt_root_size_cells, &prop); + + if (!size) { + /* ignore node and scan next one */ + return 0; + } + + pr_info("Reserved mem: found %s, memory base %lx, size %ld MiB\n", + uname, (unsigned long)base, (unsigned long)size / SZ_1M); + + if (reserved_mem_count == ARRAY_SIZE(reserved_mem)) + return -ENOSPC; + + rmem->base = base; + rmem->size = size; + strlcpy(rmem->name, uname, sizeof(rmem->name)); + + if (is_cma) { + struct cma *cma; + if (dma_contiguous_reserve_area(size, base, 0, &cma) == 0) { + rmem->cma = cma; + reserved_mem_count++; + if (of_get_flat_dt_prop(node, + "linux,default-contiguous-region", + NULL)) + dma_contiguous_set_default(cma); + } + } else if (is_reserved) { + if (memblock_remove(base, size) == 0) + reserved_mem_count++; + else + pr_err("Failed to reserve memory for %s\n", uname); + } + + return 0; +} + +static struct reserved_mem *get_dma_memory_region(struct device *dev) +{ + struct device_node *node; + const char *name; + int i; + + node = of_parse_phandle(dev->of_node, "memory-region", 0); + if (!node) + return NULL; + + name = kbasename(node->full_name); + for (i = 0; i < reserved_mem_count; i++) + if (strcmp(name, reserved_mem[i].name) == 0) + return &reserved_mem[i]; + return NULL; +} + +/** + * of_reserved_mem_device_init() - assign reserved memory region to given device + * + * This function assign memory region pointed by "memory-region" device tree + * property to the given device. + */ +void of_reserved_mem_device_init(struct device *dev) +{ + struct reserved_mem *region = get_dma_memory_region(dev); + if (!region) + return; + + if (region->cma) { + dev_set_cma_area(dev, region->cma); + pr_info("Assigned CMA %s to %s device\n", region->name, + dev_name(dev)); + } else { + if (dma_declare_coherent_memory(dev, region->base, region->base, + region->size, DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE) != 0) + pr_info("Declared reserved memory %s to %s device\n", + region->name, dev_name(dev)); + } +} + +/** + * of_reserved_mem_device_release() - release reserved memory device structures + * + * This function releases structures allocated for memory region handling for + * the given device. + */ +void of_reserved_mem_device_release(struct device *dev) +{ + struct reserved_mem *region = get_dma_memory_region(dev); + if (!region && !region->cma) + dma_release_declared_memory(dev); +} + +/** + * early_init_dt_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 (memblock) has been activated and all other + * subsystems have already allocated/reserved memory. + */ +void __init early_init_dt_scan_reserved_mem(void) +{ + of_scan_flat_dt_by_path("/memory/reserved-memory", + fdt_scan_reserved_mem, NULL); +} diff --git a/drivers/of/platform.c b/drivers/of/platform.c index e0a6514..eeca8a5 100644 --- a/drivers/of/platform.c +++ b/drivers/of/platform.c @@ -21,6 +21,7 @@ #include <linux/of_device.h> #include <linux/of_irq.h> #include <linux/of_platform.h> +#include <linux/of_reserved_mem.h> #include <linux/platform_device.h> const struct of_device_id of_default_bus_match_table[] = { @@ -218,6 +219,8 @@ struct platform_device *of_platform_device_create_pdata( dev->dev.bus = &platform_bus_type; dev->dev.platform_data = platform_data; + of_reserved_mem_device_init(&dev->dev); + /* We do not fill the DMA ops for platform devices by default. * This is currently the responsibility of the platform code * to do such, possibly using a device notifier @@ -225,6 +228,7 @@ struct platform_device *of_platform_device_create_pdata( if (of_device_add(dev) != 0) { platform_device_put(dev); + of_reserved_mem_device_release(&dev->dev); return NULL; } diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h new file mode 100644 index 0000000..c841282 --- /dev/null +++ b/include/linux/of_reserved_mem.h @@ -0,0 +1,14 @@ +#ifndef __OF_RESERVED_MEM_H +#define __OF_RESERVED_MEM_H + +#ifdef CONFIG_OF_RESERVED_MEM +void of_reserved_mem_device_init(struct device *dev); +void of_reserved_mem_device_release(struct device *dev); +void early_init_dt_scan_reserved_mem(void); +#else +static inline void of_reserved_mem_device_init(struct device *dev) { } +static inline void of_reserved_mem_device_release(struct device *dev) { } +static inline void early_init_dt_scan_reserved_mem(void) { } +#endif + +#endif /* __OF_RESERVED_MEM_H */ |
