From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH v4 3/4] drivers: of: add initialization code for dma reserved memory Date: Tue, 6 Aug 2013 08:30:07 -0500 Message-ID: References: <1375275119-12787-1-git-send-email-m.szyprowski@samsung.com> <1375275119-12787-4-git-send-email-m.szyprowski@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1375275119-12787-4-git-send-email-m.szyprowski@samsung.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Marek Szyprowski Cc: Grant Likely , Sascha Hauer , Arnd Bergmann , "devicetree-discuss@lists.ozlabs.org" , Nishanth Peethambaran , Michal Nazarewicz , linaro-mm-sig@lists.linaro.org, Marc , Kyungmin Park , Sylwester Nawrocki , Olof Johansson , Laura Abbott , Tomasz Figa , "linux-arm-kernel@lists.infradead.org" List-Id: devicetree@vger.kernel.org On Wed, Jul 31, 2013 at 7:51 AM, Marek Szyprowski wrote: > Add device tree support for contiguous and reserved memory regions > defined in device tree. Initialization is done in 2 steps. First, the > memory is reserved, what happens very early when only flattened device > tree is available. Then on device initialization the corresponding cma > and reserved regions are assigned to each device structure. > > Signed-off-by: Marek Szyprowski > Acked-by: Kyungmin Park > --- > Documentation/devicetree/bindings/memory.txt | 152 ++++++++++++++++++++++ > drivers/of/Kconfig | 6 + > drivers/of/Makefile | 1 + > drivers/of/of_reserved_mem.c | 175 ++++++++++++++++++++++++++ > include/asm-generic/dma-coherent.h | 6 + > 5 files changed, 340 insertions(+) > create mode 100644 Documentation/devicetree/bindings/memory.txt > create mode 100644 drivers/of/of_reserved_mem.c > > diff --git a/Documentation/devicetree/bindings/memory.txt b/Documentation/devicetree/bindings/memory.txt > new file mode 100644 > index 0000000..4aece19 > --- /dev/null > +++ b/Documentation/devicetree/bindings/memory.txt > @@ -0,0 +1,152 @@ > +*** 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 folllowing node: > + > +memory { > + reg = <(baseaddr1) (size1) > + (baseaddr2) (size2) > + ... > + (baseaddrN) (sizeN)>; > +}; For compatibility and since you are documenting things, these are also required: name = "memory"; device_type = "memory"; > + > +baseaddrX: the 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 additional 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 > +wit the following convention: > + > +[(label):] (name)@(address) { > + compatible = "contiguous-memory-region", "reserved-memory-region"; > + reg = <(address) (size)>; > + (linux,contiguous-region); > + (linux,default-contiguous-region); > +}; > + > +label: label given to the defined region (optional) > +name: an name given to the defined region > +address: the base address of the defined region > +size: the size of the memory region > + > +compatible: "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), alternatively if > + "reserved-memory-region" - compatibility is defined, given > + region is assigned for exclusive usage for DMA transfers > + > +linux,default-contiguous-region: property indicating that the region > + is the default region for all contiguous memory > + allocations, Linux specific (optional) > + > +Each defined region must use unique name. It is optional to specify the > +base address, so if one wants to use autoconfiguration of the base > +address, he must specify the '0' as base address in the 'reg' property > +and assign ann uniqe name to such regions. typo. > + > + > +*** Device node's properties *** > + > +Once the regions in the /memory/reserved-memory node are defined, they > +can be assigned to device nodes to enable drivers for their special use. > +The following properties are defined: > + > +dma-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 scaller@12500000 and codec@12600000 devices for contiguous s/scaller/scaler/ ? > +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. > + > +/ { > + /* ... */ > + 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 = "contiguous-memory-region"; > + reg = <0x0 0x4000000>; > + linux,default-contiguous-region; > + }; > + > + /* > + * special region for framebuffer > + */ > + display_mem: region@78000000 { > + compatible = "contiguous-memory-region", "reserved-memory-region"; > + reg = <0x78000000 0x800000>; > + }; > + > + /* > + * special region for multimedia processing devices > + */ > + multimedia_mem: region@77000000 { > + compatible = "contiguous-memory-region"; > + reg = <0x77000000 0x4000000>; > + }; > + }; > + }; > + > + /* ... */ > + > + fb0: fb@12300000 { > + status = "okay"; > + dma-memory-region = <&display_mem>; > + }; > + > + scaller: scaller@12500000 { > + status = "okay"; > + dma-memory-region = <&multimedia_mem>; > + }; > + > + codec: codec@12600000 { > + status = "okay"; > + dma-memory-region = <&multimedia_mem>; > + }; > +}; > diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig > index 80e5c13..a83ab43 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 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..d97fcdf > --- /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 > + * > + * 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 > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#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 reserved_mem_fdt_scan(unsigned long node, const char *uname, > + int depth, void *data) > +{ > + phys_addr_t base, size; > + int is_cma, is_reserved; > + unsigned long len; > + void *prop; > + > + is_cma = of_flat_dt_is_compatible(node, "contiguous-memory-region"); > + is_reserved = of_flat_dt_is_compatible(node, "reserved-memory-region"); > + > + if (!is_reserved && !(is_cma && IS_ENABLED(CONFIG_CMA))) > + return 0; > + > + prop = of_get_flat_dt_prop(node, "reg", &len); > + if (!prop || (len != 2 * sizeof(unsigned long))) { > + pr_err("Reserved mem: node %s, incorrect \"reg\" property\n", > + uname); > + return 0; > + } > + > + if (sizeof(unsigned long) == 4) { This is wrong. The sizes of the properties need to be based on #size-cells and #address-cells. There should already be code to parse reg properties correctly. > + base = be32_to_cpu(((__be32 *)prop)[0]); > + size = be32_to_cpu(((__be32 *)prop)[1]); > + } else { > + base = be64_to_cpu(((__be64 *)prop)[0]); > + size = be64_to_cpu(((__be64 *)prop)[1]); > + } > + > + 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 -ENOMEM; > + > + reserved_mem[reserved_mem_count].base = base; > + reserved_mem[reserved_mem_count].size = size; > + strcpy(reserved_mem[reserved_mem_count].name, uname); > + > + if (IS_ENABLED(CONFIG_CMA) && is_cma) { > + struct cma *cma; > + if (dma_contiguous_reserve_area(size, base, 0, &cma) == 0) { > + reserved_mem[reserved_mem_count].cma = cma; > + reserved_mem_count++; > + > + if (of_get_flat_dt_prop(node, > + "linux,default-contiguous-region", > + NULL)) > + dma_contiguous_set_default_area(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, "dma-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; > +} > + > +static void reserved_mem_assign_device_from_dt(struct device *dev) > +{ > + struct reserved_mem *region = get_dma_memory_region(dev); > + if (!region) > + return; > + > + if (region->cma) { > + dma_contiguous_add_device(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)); > + } > +} > + > +static void reserved_mem_release_device_from_dt(struct device *dev) > +{ > + struct reserved_mem *region = get_dma_memory_region(dev); > + if (!region) > + return; > + if (!region->cma) if (region && !region->cma) > + dma_release_declared_memory(dev); > +} > + > +static int reserved_mem_device_init_notifier_call(struct notifier_block *nb, > + unsigned long event, void *data) > +{ > + struct device *dev = data; > + if (event == BUS_NOTIFY_ADD_DEVICE && dev->of_node) > + reserved_mem_assign_device_from_dt(dev); > + else if (event == BUS_NOTIFY_DEL_DEVICE && dev->of_node) > + reserved_mem_release_device_from_dt(dev); > + return NOTIFY_DONE; Can you just call this directly from of_platform.c code and skip the notifiers? Rob