1 Booting the Linux/ppc kernel without Open Firmware 2 -------------------------------------------------- 3 4(c) 2005 Benjamin Herrenschmidt <benh at kernel.crashing.org>, 5 IBM Corp. 6(c) 2005 Becky Bruce <becky.bruce at freescale.com>, 7 Freescale Semiconductor, FSL SOC and 32-bit additions 8(c) 2006 MontaVista Software, Inc. 9 Flash chip node definition 10 11Table of Contents 12================= 13 14 I - Introduction 15 1) Entry point for arch/arm 16 2) Entry point for arch/powerpc 17 3) Entry point for arch/x86 18 19 II - The DT block format 20 1) Header 21 2) Device tree generalities 22 3) Device tree "structure" block 23 4) Device tree "strings" block 24 25 III - Required content of the device tree 26 1) Note about cells and address representation 27 2) Note about "compatible" properties 28 3) Note about "name" properties 29 4) Note about node and property names and character set 30 5) Required nodes and properties 31 a) The root node 32 b) The /cpus node 33 c) The /cpus/* nodes 34 d) the /memory node(s) 35 e) The /chosen node 36 f) the /soc<SOCname> node 37 38 IV - "dtc", the device tree compiler 39 40 V - Recommendations for a bootloader 41 42 VI - System-on-a-chip devices and nodes 43 1) Defining child nodes of an SOC 44 2) Representing devices without a current OF specification 45 46 VII - Specifying interrupt information for devices 47 1) interrupts property 48 2) interrupt-parent property 49 3) OpenPIC Interrupt Controllers 50 4) ISA Interrupt Controllers 51 52 VIII - Specifying device power management information (sleep property) 53 54 Appendix A - Sample SOC node for MPC8540 55 56 57Revision Information 58==================== 59 60 May 18, 2005: Rev 0.1 - Initial draft, no chapter III yet. 61 62 May 19, 2005: Rev 0.2 - Add chapter III and bits & pieces here or 63 clarifies the fact that a lot of things are 64 optional, the kernel only requires a very 65 small device tree, though it is encouraged 66 to provide an as complete one as possible. 67 68 May 24, 2005: Rev 0.3 - Precise that DT block has to be in RAM 69 - Misc fixes 70 - Define version 3 and new format version 16 71 for the DT block (version 16 needs kernel 72 patches, will be fwd separately). 73 String block now has a size, and full path 74 is replaced by unit name for more 75 compactness. 76 linux,phandle is made optional, only nodes 77 that are referenced by other nodes need it. 78 "name" property is now automatically 79 deduced from the unit name 80 81 June 1, 2005: Rev 0.4 - Correct confusion between OF_DT_END and 82 OF_DT_END_NODE in structure definition. 83 - Change version 16 format to always align 84 property data to 4 bytes. Since tokens are 85 already aligned, that means no specific 86 required alignment between property size 87 and property data. The old style variable 88 alignment would make it impossible to do 89 "simple" insertion of properties using 90 memmove (thanks Milton for 91 noticing). Updated kernel patch as well 92 - Correct a few more alignment constraints 93 - Add a chapter about the device-tree 94 compiler and the textural representation of 95 the tree that can be "compiled" by dtc. 96 97 November 21, 2005: Rev 0.5 98 - Additions/generalizations for 32-bit 99 - Changed to reflect the new arch/powerpc 100 structure 101 - Added chapter VI 102 103 104 ToDo: 105 - Add some definitions of interrupt tree (simple/complex) 106 - Add some definitions for PCI host bridges 107 - Add some common address format examples 108 - Add definitions for standard properties and "compatible" 109 names for cells that are not already defined by the existing 110 OF spec. 111 - Compare FSL SOC use of PCI to standard and make sure no new 112 node definition required. 113 - Add more information about node definitions for SOC devices 114 that currently have no standard, like the FSL CPM. 115 116 117I - Introduction 118================ 119 120During the development of the Linux/ppc64 kernel, and more 121specifically, the addition of new platform types outside of the old 122IBM pSeries/iSeries pair, it was decided to enforce some strict rules 123regarding the kernel entry and bootloader <-> kernel interfaces, in 124order to avoid the degeneration that had become the ppc32 kernel entry 125point and the way a new platform should be added to the kernel. The 126legacy iSeries platform breaks those rules as it predates this scheme, 127but no new board support will be accepted in the main tree that 128doesn't follow them properly. In addition, since the advent of the 129arch/powerpc merged architecture for ppc32 and ppc64, new 32-bit 130platforms and 32-bit platforms which move into arch/powerpc will be 131required to use these rules as well. 132 133The main requirement that will be defined in more detail below is 134the presence of a device-tree whose format is defined after Open 135Firmware specification. However, in order to make life easier 136to embedded board vendors, the kernel doesn't require the device-tree 137to represent every device in the system and only requires some nodes 138and properties to be present. This will be described in detail in 139section III, but, for example, the kernel does not require you to 140create a node for every PCI device in the system. It is a requirement 141to have a node for PCI host bridges in order to provide interrupt 142routing information and memory/IO ranges, among others. It is also 143recommended to define nodes for on chip devices and other buses that 144don't specifically fit in an existing OF specification. This creates a 145great flexibility in the way the kernel can then probe those and match 146drivers to device, without having to hard code all sorts of tables. It 147also makes it more flexible for board vendors to do minor hardware 148upgrades without significantly impacting the kernel code or cluttering 149it with special cases. 150 151 1521) Entry point for arch/arm 153--------------------------- 154 155 There is one single entry point to the kernel, at the start 156 of the kernel image. That entry point supports two calling 157 conventions. A summary of the interface is described here. A full 158 description of the boot requirements is documented in 159 Documentation/arm/Booting 160 161 a) ATAGS interface. Minimal information is passed from firmware 162 to the kernel with a tagged list of predefined parameters. 163 164 r0 : 0 165 166 r1 : Machine type number 167 168 r2 : Physical address of tagged list in system RAM 169 170 b) Entry with a flattened device-tree block. Firmware loads the 171 physical address of the flattened device tree block (dtb) into r2, 172 r1 is not used, but it is considered good practise to use a valid 173 machine number as described in Documentation/arm/Booting. 174 175 r0 : 0 176 177 r1 : Valid machine type number. When using a device tree, 178 a single machine type number will often be assigned to 179 represent a class or family of SoCs. 180 181 r2 : physical pointer to the device-tree block 182 (defined in chapter II) in RAM. Device tree can be located 183 anywhere in system RAM, but it should be aligned on a 64 bit 184 boundary. 185 186 The kernel will differentiate between ATAGS and device tree booting by 187 reading the memory pointed to by r2 and looking for either the flattened 188 device tree block magic value (0xd00dfeed) or the ATAG_CORE value at 189 offset 0x4 from r2 (0x54410001). 190 1912) Entry point for arch/powerpc 192------------------------------- 193 194 There is one single entry point to the kernel, at the start 195 of the kernel image. That entry point supports two calling 196 conventions: 197 198 a) Boot from Open Firmware. If your firmware is compatible 199 with Open Firmware (IEEE 1275) or provides an OF compatible 200 client interface API (support for "interpret" callback of 201 forth words isn't required), you can enter the kernel with: 202 203 r5 : OF callback pointer as defined by IEEE 1275 204 bindings to powerpc. Only the 32-bit client interface 205 is currently supported 206 207 r3, r4 : address & length of an initrd if any or 0 208 209 The MMU is either on or off; the kernel will run the 210 trampoline located in arch/powerpc/kernel/prom_init.c to 211 extract the device-tree and other information from open 212 firmware and build a flattened device-tree as described 213 in b). prom_init() will then re-enter the kernel using 214 the second method. This trampoline code runs in the 215 context of the firmware, which is supposed to handle all 216 exceptions during that time. 217 218 b) Direct entry with a flattened device-tree block. This entry 219 point is called by a) after the OF trampoline and can also be 220 called directly by a bootloader that does not support the Open 221 Firmware client interface. It is also used by "kexec" to 222 implement "hot" booting of a new kernel from a previous 223 running one. This method is what I will describe in more 224 details in this document, as method a) is simply standard Open 225 Firmware, and thus should be implemented according to the 226 various standard documents defining it and its binding to the 227 PowerPC platform. The entry point definition then becomes: 228 229 r3 : physical pointer to the device-tree block 230 (defined in chapter II) in RAM 231 232 r4 : physical pointer to the kernel itself. This is 233 used by the assembly code to properly disable the MMU 234 in case you are entering the kernel with MMU enabled 235 and a non-1:1 mapping. 236 237 r5 : NULL (as to differentiate with method a) 238 239 Note about SMP entry: Either your firmware puts your other 240 CPUs in some sleep loop or spin loop in ROM where you can get 241 them out via a soft reset or some other means, in which case 242 you don't need to care, or you'll have to enter the kernel 243 with all CPUs. The way to do that with method b) will be 244 described in a later revision of this document. 245 246 Board supports (platforms) are not exclusive config options. An 247 arbitrary set of board supports can be built in a single kernel 248 image. The kernel will "know" what set of functions to use for a 249 given platform based on the content of the device-tree. Thus, you 250 should: 251 252 a) add your platform support as a _boolean_ option in 253 arch/powerpc/Kconfig, following the example of PPC_PSERIES, 254 PPC_PMAC and PPC_MAPLE. The later is probably a good 255 example of a board support to start from. 256 257 b) create your main platform file as 258 "arch/powerpc/platforms/myplatform/myboard_setup.c" and add it 259 to the Makefile under the condition of your CONFIG_ 260 option. This file will define a structure of type "ppc_md" 261 containing the various callbacks that the generic code will 262 use to get to your platform specific code 263 264 A kernel image may support multiple platforms, but only if the 265 platforms feature the same core architecture. A single kernel build 266 cannot support both configurations with Book E and configurations 267 with classic Powerpc architectures. 268 2693) Entry point for arch/x86 270------------------------------- 271 272 There is one single 32bit entry point to the kernel at code32_start, 273 the decompressor (the real mode entry point goes to the same 32bit 274 entry point once it switched into protected mode). That entry point 275 supports one calling convention which is documented in 276 Documentation/x86/boot.txt 277 The physical pointer to the device-tree block (defined in chapter II) 278 is passed via setup_data which requires at least boot protocol 2.09. 279 The type filed is defined as 280 281 #define SETUP_DTB 2 282 283 This device-tree is used as an extension to the "boot page". As such it 284 does not parse / consider data which is already covered by the boot 285 page. This includes memory size, reserved ranges, command line arguments 286 or initrd address. It simply holds information which can not be retrieved 287 otherwise like interrupt routing or a list of devices behind an I2C bus. 288 289II - The DT block format 290======================== 291 292 293This chapter defines the actual format of the flattened device-tree 294passed to the kernel. The actual content of it and kernel requirements 295are described later. You can find example of code manipulating that 296format in various places, including arch/powerpc/kernel/prom_init.c 297which will generate a flattened device-tree from the Open Firmware 298representation, or the fs2dt utility which is part of the kexec tools 299which will generate one from a filesystem representation. It is 300expected that a bootloader like uboot provides a bit more support, 301that will be discussed later as well. 302 303Note: The block has to be in main memory. It has to be accessible in 304both real mode and virtual mode with no mapping other than main 305memory. If you are writing a simple flash bootloader, it should copy 306the block to RAM before passing it to the kernel. 307 308 3091) Header 310--------- 311 312 The kernel is passed the physical address pointing to an area of memory 313 that is roughly described in include/linux/of_fdt.h by the structure 314 boot_param_header: 315 316struct boot_param_header { 317 u32 magic; /* magic word OF_DT_HEADER */ 318 u32 totalsize; /* total size of DT block */ 319 u32 off_dt_struct; /* offset to structure */ 320 u32 off_dt_strings; /* offset to strings */ 321 u32 off_mem_rsvmap; /* offset to memory reserve map 322 */ 323 u32 version; /* format version */ 324 u32 last_comp_version; /* last compatible version */ 325 326 /* version 2 fields below */ 327 u32 boot_cpuid_phys; /* Which physical CPU id we're 328 booting on */ 329 /* version 3 fields below */ 330 u32 size_dt_strings; /* size of the strings block */ 331 332 /* version 17 fields below */ 333 u32 size_dt_struct; /* size of the DT structure block */ 334}; 335 336 Along with the constants: 337 338/* Definitions used by the flattened device tree */ 339#define OF_DT_HEADER 0xd00dfeed /* 4: version, 340 4: total size */ 341#define OF_DT_BEGIN_NODE 0x1 /* Start node: full name 342 */ 343#define OF_DT_END_NODE 0x2 /* End node */ 344#define OF_DT_PROP 0x3 /* Property: name off, 345 size, content */ 346#define OF_DT_END 0x9 347 348 All values in this header are in big endian format, the various 349 fields in this header are defined more precisely below. All 350 "offset" values are in bytes from the start of the header; that is 351 from the physical base address of the device tree block. 352 353 - magic 354 355 This is a magic value that "marks" the beginning of the 356 device-tree block header. It contains the value 0xd00dfeed and is 357 defined by the constant OF_DT_HEADER 358 359 - totalsize 360 361 This is the total size of the DT block including the header. The 362 "DT" block should enclose all data structures defined in this 363 chapter (who are pointed to by offsets in this header). That is, 364 the device-tree structure, strings, and the memory reserve map. 365 366 - off_dt_struct 367 368 This is an offset from the beginning of the header to the start 369 of the "structure" part the device tree. (see 2) device tree) 370 371 - off_dt_strings 372 373 This is an offset from the beginning of the header to the start 374 of the "strings" part of the device-tree 375 376 - off_mem_rsvmap 377 378 This is an offset from the beginning of the header to the start 379 of the reserved memory map. This map is a list of pairs of 64- 380 bit integers. Each pair is a physical address and a size. The 381 list is terminated by an entry of size 0. This map provides the 382 kernel with a list of physical memory areas that are "reserved" 383 and thus not to be used for memory allocations, especially during 384 early initialization. The kernel needs to allocate memory during 385 boot for things like un-flattening the device-tree, allocating an 386 MMU hash table, etc... Those allocations must be done in such a 387 way to avoid overriding critical things like, on Open Firmware 388 capable machines, the RTAS instance, or on some pSeries, the TCE 389 tables used for the iommu. Typically, the reserve map should 390 contain _at least_ this DT block itself (header,total_size). If 391 you are passing an initrd to the kernel, you should reserve it as 392 well. You do not need to reserve the kernel image itself. The map 393 should be 64-bit aligned. 394 395 - version 396 397 This is the version of this structure. Version 1 stops 398 here. Version 2 adds an additional field boot_cpuid_phys. 399 Version 3 adds the size of the strings block, allowing the kernel 400 to reallocate it easily at boot and free up the unused flattened 401 structure after expansion. Version 16 introduces a new more 402 "compact" format for the tree itself that is however not backward 403 compatible. Version 17 adds an additional field, size_dt_struct, 404 allowing it to be reallocated or moved more easily (this is 405 particularly useful for bootloaders which need to make 406 adjustments to a device tree based on probed information). You 407 should always generate a structure of the highest version defined 408 at the time of your implementation. Currently that is version 17, 409 unless you explicitly aim at being backward compatible. 410 411 - last_comp_version 412 413 Last compatible version. This indicates down to what version of 414 the DT block you are backward compatible. For example, version 2 415 is backward compatible with version 1 (that is, a kernel build 416 for version 1 will be able to boot with a version 2 format). You 417 should put a 1 in this field if you generate a device tree of 418 version 1 to 3, or 16 if you generate a tree of version 16 or 17 419 using the new unit name format. 420 421 - boot_cpuid_phys 422 423 This field only exist on version 2 headers. It indicate which 424 physical CPU ID is calling the kernel entry point. This is used, 425 among others, by kexec. If you are on an SMP system, this value 426 should match the content of the "reg" property of the CPU node in 427 the device-tree corresponding to the CPU calling the kernel entry 428 point (see further chapters for more information on the required 429 device-tree contents) 430 431 - size_dt_strings 432 433 This field only exists on version 3 and later headers. It 434 gives the size of the "strings" section of the device tree (which 435 starts at the offset given by off_dt_strings). 436 437 - size_dt_struct 438 439 This field only exists on version 17 and later headers. It gives 440 the size of the "structure" section of the device tree (which 441 starts at the offset given by off_dt_struct). 442 443 So the typical layout of a DT block (though the various parts don't 444 need to be in that order) looks like this (addresses go from top to 445 bottom): 446 447 448 ------------------------------ 449 base -> | struct boot_param_header | 450 ------------------------------ 451 | (alignment gap) (*) | 452 ------------------------------ 453 | memory reserve map | 454 ------------------------------ 455 | (alignment gap) | 456 ------------------------------ 457 | | 458 | device-tree structure | 459 | | 460 ------------------------------ 461 | (alignment gap) | 462 ------------------------------ 463 | | 464 | device-tree strings | 465 | | 466 -----> ------------------------------ 467 | 468 | 469 --- (base + totalsize) 470 471 (*) The alignment gaps are not necessarily present; their presence 472 and size are dependent on the various alignment requirements of 473 the individual data blocks. 474 475 4762) Device tree generalities 477--------------------------- 478 479This device-tree itself is separated in two different blocks, a 480structure block and a strings block. Both need to be aligned to a 4 481byte boundary. 482 483First, let's quickly describe the device-tree concept before detailing 484the storage format. This chapter does _not_ describe the detail of the 485required types of nodes & properties for the kernel, this is done 486later in chapter III. 487 488The device-tree layout is strongly inherited from the definition of 489the Open Firmware IEEE 1275 device-tree. It's basically a tree of 490nodes, each node having two or more named properties. A property can 491have a value or not. 492 493It is a tree, so each node has one and only one parent except for the 494root node who has no parent. 495 496A node has 2 names. The actual node name is generally contained in a 497property of type "name" in the node property list whose value is a 498zero terminated string and is mandatory for version 1 to 3 of the 499format definition (as it is in Open Firmware). Version 16 makes it 500optional as it can generate it from the unit name defined below. 501 502There is also a "unit name" that is used to differentiate nodes with 503the same name at the same level, it is usually made of the node 504names, the "@" sign, and a "unit address", which definition is 505specific to the bus type the node sits on. 506 507The unit name doesn't exist as a property per-se but is included in 508the device-tree structure. It is typically used to represent "path" in 509the device-tree. More details about the actual format of these will be 510below. 511 512The kernel generic code does not make any formal use of the 513unit address (though some board support code may do) so the only real 514requirement here for the unit address is to ensure uniqueness of 515the node unit name at a given level of the tree. Nodes with no notion 516of address and no possible sibling of the same name (like /memory or 517/cpus) may omit the unit address in the context of this specification, 518or use the "@0" default unit address. The unit name is used to define 519a node "full path", which is the concatenation of all parent node 520unit names separated with "/". 521 522The root node doesn't have a defined name, and isn't required to have 523a name property either if you are using version 3 or earlier of the 524format. It also has no unit address (no @ symbol followed by a unit 525address). The root node unit name is thus an empty string. The full 526path to the root node is "/". 527 528Every node which actually represents an actual device (that is, a node 529which isn't only a virtual "container" for more nodes, like "/cpus" 530is) is also required to have a "compatible" property indicating the 531specific hardware and an optional list of devices it is fully 532backwards compatible with. 533 534Finally, every node that can be referenced from a property in another 535node is required to have either a "phandle" or a "linux,phandle" 536property. Real Open Firmware implementations provide a unique 537"phandle" value for every node that the "prom_init()" trampoline code 538turns into "linux,phandle" properties. However, this is made optional 539if the flattened device tree is used directly. An example of a node 540referencing another node via "phandle" is when laying out the 541interrupt tree which will be described in a further version of this 542document. 543 544The "phandle" property is a 32-bit value that uniquely 545identifies a node. You are free to use whatever values or system of 546values, internal pointers, or whatever to generate these, the only 547requirement is that every node for which you provide that property has 548a unique value for it. 549 550Here is an example of a simple device-tree. In this example, an "o" 551designates a node followed by the node unit name. Properties are 552presented with their name followed by their content. "content" 553represents an ASCII string (zero terminated) value, while <content> 554represents a 32-bit hexadecimal value. The various nodes in this 555example will be discussed in a later chapter. At this point, it is 556only meant to give you a idea of what a device-tree looks like. I have 557purposefully kept the "name" and "linux,phandle" properties which 558aren't necessary in order to give you a better idea of what the tree 559looks like in practice. 560 561 / o device-tree 562 |- name = "device-tree" 563 |- model = "MyBoardName" 564 |- compatible = "MyBoardFamilyName" 565 |- #address-cells = <2> 566 |- #size-cells = <2> 567 |- linux,phandle = <0> 568 | 569 o cpus 570 | | - name = "cpus" 571 | | - linux,phandle = <1> 572 | | - #address-cells = <1> 573 | | - #size-cells = <0> 574 | | 575 | o PowerPC,970@0 576 | |- name = "PowerPC,970" 577 | |- device_type = "cpu" 578 | |- reg = <0> 579 | |- clock-frequency = <5f5e1000> 580 | |- 64-bit 581 | |- linux,phandle = <2> 582 | 583 o memory@0 584 | |- name = "memory" 585 | |- device_type = "memory" 586 | |- reg = <00000000 00000000 00000000 20000000> 587 | |- linux,phandle = <3> 588 | 589 o chosen 590 |- name = "chosen" 591 |- bootargs = "root=/dev/sda2" 592 |- linux,phandle = <4> 593 594This tree is almost a minimal tree. It pretty much contains the 595minimal set of required nodes and properties to boot a linux kernel; 596that is, some basic model information at the root, the CPUs, and the 597physical memory layout. It also includes misc information passed 598through /chosen, like in this example, the platform type (mandatory) 599and the kernel command line arguments (optional). 600 601The /cpus/PowerPC,970@0/64-bit property is an example of a 602property without a value. All other properties have a value. The 603significance of the #address-cells and #size-cells properties will be 604explained in chapter IV which defines precisely the required nodes and 605properties and their content. 606 607 6083) Device tree "structure" block 609 610The structure of the device tree is a linearized tree structure. The 611"OF_DT_BEGIN_NODE" token starts a new node, and the "OF_DT_END_NODE" 612ends that node definition. Child nodes are simply defined before 613"OF_DT_END_NODE" (that is nodes within the node). A 'token' is a 32 614bit value. The tree has to be "finished" with a OF_DT_END token 615 616Here's the basic structure of a single node: 617 618 * token OF_DT_BEGIN_NODE (that is 0x00000001) 619 * for version 1 to 3, this is the node full path as a zero 620 terminated string, starting with "/". For version 16 and later, 621 this is the node unit name only (or an empty string for the 622 root node) 623 * [align gap to next 4 bytes boundary] 624 * for each property: 625 * token OF_DT_PROP (that is 0x00000003) 626 * 32-bit value of property value size in bytes (or 0 if no 627 value) 628 * 32-bit value of offset in string block of property name 629 * property value data if any 630 * [align gap to next 4 bytes boundary] 631 * [child nodes if any] 632 * token OF_DT_END_NODE (that is 0x00000002) 633 634So the node content can be summarized as a start token, a full path, 635a list of properties, a list of child nodes, and an end token. Every 636child node is a full node structure itself as defined above. 637 638NOTE: The above definition requires that all property definitions for 639a particular node MUST precede any subnode definitions for that node. 640Although the structure would not be ambiguous if properties and 641subnodes were intermingled, the kernel parser requires that the 642properties come first (up until at least 2.6.22). Any tools 643manipulating a flattened tree must take care to preserve this 644constraint. 645 6464) Device tree "strings" block 647 648In order to save space, property names, which are generally redundant, 649are stored separately in the "strings" block. This block is simply the 650whole bunch of zero terminated strings for all property names 651concatenated together. The device-tree property definitions in the 652structure block will contain offset values from the beginning of the 653strings block. 654 655 656III - Required content of the device tree 657========================================= 658 659WARNING: All "linux,*" properties defined in this document apply only 660to a flattened device-tree. If your platform uses a real 661implementation of Open Firmware or an implementation compatible with 662the Open Firmware client interface, those properties will be created 663by the trampoline code in the kernel's prom_init() file. For example, 664that's where you'll have to add code to detect your board model and 665set the platform number. However, when using the flattened device-tree 666entry point, there is no prom_init() pass, and thus you have to 667provide those properties yourself. 668 669 6701) Note about cells and address representation 671---------------------------------------------- 672 673The general rule is documented in the various Open Firmware 674documentations. If you choose to describe a bus with the device-tree 675and there exist an OF bus binding, then you should follow the 676specification. However, the kernel does not require every single 677device or bus to be described by the device tree. 678 679In general, the format of an address for a device is defined by the 680parent bus type, based on the #address-cells and #size-cells 681properties. Note that the parent's parent definitions of #address-cells 682and #size-cells are not inherited so every node with children must specify 683them. The kernel requires the root node to have those properties defining 684addresses format for devices directly mapped on the processor bus. 685 686Those 2 properties define 'cells' for representing an address and a 687size. A "cell" is a 32-bit number. For example, if both contain 2 688like the example tree given above, then an address and a size are both 689composed of 2 cells, and each is a 64-bit number (cells are 690concatenated and expected to be in big endian format). Another example 691is the way Apple firmware defines them, with 2 cells for an address 692and one cell for a size. Most 32-bit implementations should define 693#address-cells and #size-cells to 1, which represents a 32-bit value. 694Some 32-bit processors allow for physical addresses greater than 32 695bits; these processors should define #address-cells as 2. 696 697"reg" properties are always a tuple of the type "address size" where 698the number of cells of address and size is specified by the bus 699#address-cells and #size-cells. When a bus supports various address 700spaces and other flags relative to a given address allocation (like 701prefetchable, etc...) those flags are usually added to the top level 702bits of the physical address. For example, a PCI physical address is 703made of 3 cells, the bottom two containing the actual address itself 704while the top cell contains address space indication, flags, and pci 705bus & device numbers. 706 707For buses that support dynamic allocation, it's the accepted practice 708to then not provide the address in "reg" (keep it 0) though while 709providing a flag indicating the address is dynamically allocated, and 710then, to provide a separate "assigned-addresses" property that 711contains the fully allocated addresses. See the PCI OF bindings for 712details. 713 714In general, a simple bus with no address space bits and no dynamic 715allocation is preferred if it reflects your hardware, as the existing 716kernel address parsing functions will work out of the box. If you 717define a bus type with a more complex address format, including things 718like address space bits, you'll have to add a bus translator to the 719prom_parse.c file of the recent kernels for your bus type. 720 721The "reg" property only defines addresses and sizes (if #size-cells is 722non-0) within a given bus. In order to translate addresses upward 723(that is into parent bus addresses, and possibly into CPU physical 724addresses), all buses must contain a "ranges" property. If the 725"ranges" property is missing at a given level, it's assumed that 726translation isn't possible, i.e., the registers are not visible on the 727parent bus. The format of the "ranges" property for a bus is a list 728of: 729 730 bus address, parent bus address, size 731 732"bus address" is in the format of the bus this bus node is defining, 733that is, for a PCI bridge, it would be a PCI address. Thus, (bus 734address, size) defines a range of addresses for child devices. "parent 735bus address" is in the format of the parent bus of this bus. For 736example, for a PCI host controller, that would be a CPU address. For a 737PCI<->ISA bridge, that would be a PCI address. It defines the base 738address in the parent bus where the beginning of that range is mapped. 739 740For new 64-bit board support, I recommend either the 2/2 format or 741Apple's 2/1 format which is slightly more compact since sizes usually 742fit in a single 32-bit word. New 32-bit board support should use a 7431/1 format, unless the processor supports physical addresses greater 744than 32-bits, in which case a 2/1 format is recommended. 745 746Alternatively, the "ranges" property may be empty, indicating that the 747registers are visible on the parent bus using an identity mapping 748translation. In other words, the parent bus address space is the same 749as the child bus address space. 750 7512) Note about "compatible" properties 752------------------------------------- 753 754These properties are optional, but recommended in devices and the root 755node. The format of a "compatible" property is a list of concatenated 756zero terminated strings. They allow a device to express its 757compatibility with a family of similar devices, in some cases, 758allowing a single driver to match against several devices regardless 759of their actual names. 760 7613) Note about "name" properties 762------------------------------- 763 764While earlier users of Open Firmware like OldWorld macintoshes tended 765to use the actual device name for the "name" property, it's nowadays 766considered a good practice to use a name that is closer to the device 767class (often equal to device_type). For example, nowadays, Ethernet 768controllers are named "ethernet", an additional "model" property 769defining precisely the chip type/model, and "compatible" property 770defining the family in case a single driver can driver more than one 771of these chips. However, the kernel doesn't generally put any 772restriction on the "name" property; it is simply considered good 773practice to follow the standard and its evolutions as closely as 774possible. 775 776Note also that the new format version 16 makes the "name" property 777optional. If it's absent for a node, then the node's unit name is then 778used to reconstruct the name. That is, the part of the unit name 779before the "@" sign is used (or the entire unit name if no "@" sign 780is present). 781 7824) Note about node and property names and character set 783------------------------------------------------------- 784 785While Open Firmware provides more flexible usage of 8859-1, this 786specification enforces more strict rules. Nodes and properties should 787be comprised only of ASCII characters 'a' to 'z', '0' to 788'9', ',', '.', '_', '+', '#', '?', and '-'. Node names additionally 789allow uppercase characters 'A' to 'Z' (property names should be 790lowercase. The fact that vendors like Apple don't respect this rule is 791irrelevant here). Additionally, node and property names should always 792begin with a character in the range 'a' to 'z' (or 'A' to 'Z' for node 793names). 794 795The maximum number of characters for both nodes and property names 796is 31. In the case of node names, this is only the leftmost part of 797a unit name (the pure "name" property), it doesn't include the unit 798address which can extend beyond that limit. 799 800 8015) Required nodes and properties 802-------------------------------- 803 These are all that are currently required. However, it is strongly 804 recommended that you expose PCI host bridges as documented in the 805 PCI binding to Open Firmware, and your interrupt tree as documented 806 in OF interrupt tree specification. 807 808 a) The root node 809 810 The root node requires some properties to be present: 811 812 - model : this is your board name/model 813 - #address-cells : address representation for "root" devices 814 - #size-cells: the size representation for "root" devices 815 - compatible : the board "family" generally finds its way here, 816 for example, if you have 2 board models with a similar layout, 817 that typically get driven by the same platform code in the 818 kernel, you would specify the exact board model in the 819 compatible property followed by an entry that represents the SoC 820 model. 821 822 The root node is also generally where you add additional properties 823 specific to your board like the serial number if any, that sort of 824 thing. It is recommended that if you add any "custom" property whose 825 name may clash with standard defined ones, you prefix them with your 826 vendor name and a comma. 827 828 b) The /cpus node 829 830 This node is the parent of all individual CPU nodes. It doesn't 831 have any specific requirements, though it's generally good practice 832 to have at least: 833 834 #address-cells = <00000001> 835 #size-cells = <00000000> 836 837 This defines that the "address" for a CPU is a single cell, and has 838 no meaningful size. This is not necessary but the kernel will assume 839 that format when reading the "reg" properties of a CPU node, see 840 below 841 842 c) The /cpus/* nodes 843 844 So under /cpus, you are supposed to create a node for every CPU on 845 the machine. There is no specific restriction on the name of the 846 CPU, though it's common to call it <architecture>,<core>. For 847 example, Apple uses PowerPC,G5 while IBM uses PowerPC,970FX. 848 However, the Generic Names convention suggests that it would be 849 better to simply use 'cpu' for each cpu node and use the compatible 850 property to identify the specific cpu core. 851 852 Required properties: 853 854 - device_type : has to be "cpu" 855 - reg : This is the physical CPU number, it's a single 32-bit cell 856 and is also used as-is as the unit number for constructing the 857 unit name in the full path. For example, with 2 CPUs, you would 858 have the full path: 859 /cpus/PowerPC,970FX@0 860 /cpus/PowerPC,970FX@1 861 (unit addresses do not require leading zeroes) 862 - d-cache-block-size : one cell, L1 data cache block size in bytes (*) 863 - i-cache-block-size : one cell, L1 instruction cache block size in 864 bytes 865 - d-cache-size : one cell, size of L1 data cache in bytes 866 - i-cache-size : one cell, size of L1 instruction cache in bytes 867 868(*) The cache "block" size is the size on which the cache management 869instructions operate. Historically, this document used the cache 870"line" size here which is incorrect. The kernel will prefer the cache 871block size and will fallback to cache line size for backward 872compatibility. 873 874 Recommended properties: 875 876 - timebase-frequency : a cell indicating the frequency of the 877 timebase in Hz. This is not directly used by the generic code, 878 but you are welcome to copy/paste the pSeries code for setting 879 the kernel timebase/decrementer calibration based on this 880 value. 881 - clock-frequency : a cell indicating the CPU core clock frequency 882 in Hz. A new property will be defined for 64-bit values, but if 883 your frequency is < 4Ghz, one cell is enough. Here as well as 884 for the above, the common code doesn't use that property, but 885 you are welcome to re-use the pSeries or Maple one. A future 886 kernel version might provide a common function for this. 887 - d-cache-line-size : one cell, L1 data cache line size in bytes 888 if different from the block size 889 - i-cache-line-size : one cell, L1 instruction cache line size in 890 bytes if different from the block size 891 892 You are welcome to add any property you find relevant to your board, 893 like some information about the mechanism used to soft-reset the 894 CPUs. For example, Apple puts the GPIO number for CPU soft reset 895 lines in there as a "soft-reset" property since they start secondary 896 CPUs by soft-resetting them. 897 898 899 d) the /memory node(s) 900 901 To define the physical memory layout of your board, you should 902 create one or more memory node(s). You can either create a single 903 node with all memory ranges in its reg property, or you can create 904 several nodes, as you wish. The unit address (@ part) used for the 905 full path is the address of the first range of memory defined by a 906 given node. If you use a single memory node, this will typically be 907 @0. 908 909 Required properties: 910 911 - device_type : has to be "memory" 912 - reg : This property contains all the physical memory ranges of 913 your board. It's a list of addresses/sizes concatenated 914 together, with the number of cells of each defined by the 915 #address-cells and #size-cells of the root node. For example, 916 with both of these properties being 2 like in the example given 917 earlier, a 970 based machine with 6Gb of RAM could typically 918 have a "reg" property here that looks like: 919 920 00000000 00000000 00000000 80000000 921 00000001 00000000 00000001 00000000 922 923 That is a range starting at 0 of 0x80000000 bytes and a range 924 starting at 0x100000000 and of 0x100000000 bytes. You can see 925 that there is no memory covering the IO hole between 2Gb and 926 4Gb. Some vendors prefer splitting those ranges into smaller 927 segments, but the kernel doesn't care. 928 929 e) The /chosen node 930 931 This node is a bit "special". Normally, that's where Open Firmware 932 puts some variable environment information, like the arguments, or 933 the default input/output devices. 934 935 This specification makes a few of these mandatory, but also defines 936 some linux-specific properties that would be normally constructed by 937 the prom_init() trampoline when booting with an OF client interface, 938 but that you have to provide yourself when using the flattened format. 939 940 Recommended properties: 941 942 - bootargs : This zero-terminated string is passed as the kernel 943 command line 944 - linux,stdout-path : This is the full path to your standard 945 console device if any. Typically, if you have serial devices on 946 your board, you may want to put the full path to the one set as 947 the default console in the firmware here, for the kernel to pick 948 it up as its own default console. 949 950 Note that u-boot creates and fills in the chosen node for platforms 951 that use it. 952 953 (Note: a practice that is now obsolete was to include a property 954 under /chosen called interrupt-controller which had a phandle value 955 that pointed to the main interrupt controller) 956 957 f) the /soc<SOCname> node 958 959 This node is used to represent a system-on-a-chip (SoC) and must be 960 present if the processor is a SoC. The top-level soc node contains 961 information that is global to all devices on the SoC. The node name 962 should contain a unit address for the SoC, which is the base address 963 of the memory-mapped register set for the SoC. The name of an SoC 964 node should start with "soc", and the remainder of the name should 965 represent the part number for the soc. For example, the MPC8540's 966 soc node would be called "soc8540". 967 968 Required properties: 969 970 - ranges : Should be defined as specified in 1) to describe the 971 translation of SoC addresses for memory mapped SoC registers. 972 - bus-frequency: Contains the bus frequency for the SoC node. 973 Typically, the value of this field is filled in by the boot 974 loader. 975 - compatible : Exact model of the SoC 976 977 978 Recommended properties: 979 980 - reg : This property defines the address and size of the 981 memory-mapped registers that are used for the SOC node itself. 982 It does not include the child device registers - these will be 983 defined inside each child node. The address specified in the 984 "reg" property should match the unit address of the SOC node. 985 - #address-cells : Address representation for "soc" devices. The 986 format of this field may vary depending on whether or not the 987 device registers are memory mapped. For memory mapped 988 registers, this field represents the number of cells needed to 989 represent the address of the registers. For SOCs that do not 990 use MMIO, a special address format should be defined that 991 contains enough cells to represent the required information. 992 See 1) above for more details on defining #address-cells. 993 - #size-cells : Size representation for "soc" devices 994 - #interrupt-cells : Defines the width of cells used to represent 995 interrupts. Typically this value is <2>, which includes a 996 32-bit number that represents the interrupt number, and a 997 32-bit number that represents the interrupt sense and level. 998 This field is only needed if the SOC contains an interrupt 999 controller. 1000 1001 The SOC node may contain child nodes for each SOC device that the 1002 platform uses. Nodes should not be created for devices which exist 1003 on the SOC but are not used by a particular platform. See chapter VI 1004 for more information on how to specify devices that are part of a SOC. 1005 1006 Example SOC node for the MPC8540: 1007 1008 soc8540@e0000000 { 1009 #address-cells = <1>; 1010 #size-cells = <1>; 1011 #interrupt-cells = <2>; 1012 device_type = "soc"; 1013 ranges = <00000000 e0000000 00100000> 1014 reg = <e0000000 00003000>; 1015 bus-frequency = <0>; 1016 } 1017 1018 1019 1020IV - "dtc", the device tree compiler 1021==================================== 1022 1023 1024dtc source code can be found at 1025<http://git.jdl.com/gitweb/?p=dtc.git> 1026 1027WARNING: This version is still in early development stage; the 1028resulting device-tree "blobs" have not yet been validated with the 1029kernel. The current generated block lacks a useful reserve map (it will 1030be fixed to generate an empty one, it's up to the bootloader to fill 1031it up) among others. The error handling needs work, bugs are lurking, 1032etc... 1033 1034dtc basically takes a device-tree in a given format and outputs a 1035device-tree in another format. The currently supported formats are: 1036 1037 Input formats: 1038 ------------- 1039 1040 - "dtb": "blob" format, that is a flattened device-tree block 1041 with 1042 header all in a binary blob. 1043 - "dts": "source" format. This is a text file containing a 1044 "source" for a device-tree. The format is defined later in this 1045 chapter. 1046 - "fs" format. This is a representation equivalent to the 1047 output of /proc/device-tree, that is nodes are directories and 1048 properties are files 1049 1050 Output formats: 1051 --------------- 1052 1053 - "dtb": "blob" format 1054 - "dts": "source" format 1055 - "asm": assembly language file. This is a file that can be 1056 sourced by gas to generate a device-tree "blob". That file can 1057 then simply be added to your Makefile. Additionally, the 1058 assembly file exports some symbols that can be used. 1059 1060 1061The syntax of the dtc tool is 1062 1063 dtc [-I <input-format>] [-O <output-format>] 1064 [-o output-filename] [-V output_version] input_filename 1065 1066 1067The "output_version" defines what version of the "blob" format will be 1068generated. Supported versions are 1,2,3 and 16. The default is 1069currently version 3 but that may change in the future to version 16. 1070 1071Additionally, dtc performs various sanity checks on the tree, like the 1072uniqueness of linux, phandle properties, validity of strings, etc... 1073 1074The format of the .dts "source" file is "C" like, supports C and C++ 1075style comments. 1076 1077/ { 1078} 1079 1080The above is the "device-tree" definition. It's the only statement 1081supported currently at the toplevel. 1082 1083/ { 1084 property1 = "string_value"; /* define a property containing a 0 1085 * terminated string 1086 */ 1087 1088 property2 = <1234abcd>; /* define a property containing a 1089 * numerical 32-bit value (hexadecimal) 1090 */ 1091 1092 property3 = <12345678 12345678 deadbeef>; 1093 /* define a property containing 3 1094 * numerical 32-bit values (cells) in 1095 * hexadecimal 1096 */ 1097 property4 = [0a 0b 0c 0d de ea ad be ef]; 1098 /* define a property whose content is 1099 * an arbitrary array of bytes 1100 */ 1101 1102 childnode@address { /* define a child node named "childnode" 1103 * whose unit name is "childnode at 1104 * address" 1105 */ 1106 1107 childprop = "hello\n"; /* define a property "childprop" of 1108 * childnode (in this case, a string) 1109 */ 1110 }; 1111}; 1112 1113Nodes can contain other nodes etc... thus defining the hierarchical 1114structure of the tree. 1115 1116Strings support common escape sequences from C: "\n", "\t", "\r", 1117"\(octal value)", "\x(hex value)". 1118 1119It is also suggested that you pipe your source file through cpp (gcc 1120preprocessor) so you can use #include's, #define for constants, etc... 1121 1122Finally, various options are planned but not yet implemented, like 1123automatic generation of phandles, labels (exported to the asm file so 1124you can point to a property content and change it easily from whatever 1125you link the device-tree with), label or path instead of numeric value 1126in some cells to "point" to a node (replaced by a phandle at compile 1127time), export of reserve map address to the asm file, ability to 1128specify reserve map content at compile time, etc... 1129 1130We may provide a .h include file with common definitions of that 1131proves useful for some properties (like building PCI properties or 1132interrupt maps) though it may be better to add a notion of struct 1133definitions to the compiler... 1134 1135 1136V - Recommendations for a bootloader 1137==================================== 1138 1139 1140Here are some various ideas/recommendations that have been proposed 1141while all this has been defined and implemented. 1142 1143 - The bootloader may want to be able to use the device-tree itself 1144 and may want to manipulate it (to add/edit some properties, 1145 like physical memory size or kernel arguments). At this point, 2 1146 choices can be made. Either the bootloader works directly on the 1147 flattened format, or the bootloader has its own internal tree 1148 representation with pointers (similar to the kernel one) and 1149 re-flattens the tree when booting the kernel. The former is a bit 1150 more difficult to edit/modify, the later requires probably a bit 1151 more code to handle the tree structure. Note that the structure 1152 format has been designed so it's relatively easy to "insert" 1153 properties or nodes or delete them by just memmoving things 1154 around. It contains no internal offsets or pointers for this 1155 purpose. 1156 1157 - An example of code for iterating nodes & retrieving properties 1158 directly from the flattened tree format can be found in the kernel 1159 file drivers/of/fdt.c. Look at the of_scan_flat_dt() function, 1160 its usage in early_init_devtree(), and the corresponding various 1161 early_init_dt_scan_*() callbacks. That code can be re-used in a 1162 GPL bootloader, and as the author of that code, I would be happy 1163 to discuss possible free licensing to any vendor who wishes to 1164 integrate all or part of this code into a non-GPL bootloader. 1165 (reference needed; who is 'I' here? ---gcl Jan 31, 2011) 1166 1167 1168 1169VI - System-on-a-chip devices and nodes 1170======================================= 1171 1172Many companies are now starting to develop system-on-a-chip 1173processors, where the processor core (CPU) and many peripheral devices 1174exist on a single piece of silicon. For these SOCs, an SOC node 1175should be used that defines child nodes for the devices that make 1176up the SOC. While platforms are not required to use this model in 1177order to boot the kernel, it is highly encouraged that all SOC 1178implementations define as complete a flat-device-tree as possible to 1179describe the devices on the SOC. This will allow for the 1180genericization of much of the kernel code. 1181 1182 11831) Defining child nodes of an SOC 1184--------------------------------- 1185 1186Each device that is part of an SOC may have its own node entry inside 1187the SOC node. For each device that is included in the SOC, the unit 1188address property represents the address offset for this device's 1189memory-mapped registers in the parent's address space. The parent's 1190address space is defined by the "ranges" property in the top-level soc 1191node. The "reg" property for each node that exists directly under the 1192SOC node should contain the address mapping from the child address space 1193to the parent SOC address space and the size of the device's 1194memory-mapped register file. 1195 1196For many devices that may exist inside an SOC, there are predefined 1197specifications for the format of the device tree node. All SOC child 1198nodes should follow these specifications, except where noted in this 1199document. 1200 1201See appendix A for an example partial SOC node definition for the 1202MPC8540. 1203 1204 12052) Representing devices without a current OF specification 1206---------------------------------------------------------- 1207 1208Currently, there are many devices on SoCs that do not have a standard 1209representation defined as part of the Open Firmware specifications, 1210mainly because the boards that contain these SoCs are not currently 1211booted using Open Firmware. Binding documentation for new devices 1212should be added to the Documentation/devicetree/bindings directory. 1213That directory will expand as device tree support is added to more and 1214more SoCs. 1215 1216 1217VII - Specifying interrupt information for devices 1218=================================================== 1219 1220The device tree represents the buses and devices of a hardware 1221system in a form similar to the physical bus topology of the 1222hardware. 1223 1224In addition, a logical 'interrupt tree' exists which represents the 1225hierarchy and routing of interrupts in the hardware. 1226 1227The interrupt tree model is fully described in the 1228document "Open Firmware Recommended Practice: Interrupt 1229Mapping Version 0.9". The document is available at: 1230<http://playground.sun.com/1275/practice>. 1231 12321) interrupts property 1233---------------------- 1234 1235Devices that generate interrupts to a single interrupt controller 1236should use the conventional OF representation described in the 1237OF interrupt mapping documentation. 1238 1239Each device which generates interrupts must have an 'interrupt' 1240property. The interrupt property value is an arbitrary number of 1241of 'interrupt specifier' values which describe the interrupt or 1242interrupts for the device. 1243 1244The encoding of an interrupt specifier is determined by the 1245interrupt domain in which the device is located in the 1246interrupt tree. The root of an interrupt domain specifies in 1247its #interrupt-cells property the number of 32-bit cells 1248required to encode an interrupt specifier. See the OF interrupt 1249mapping documentation for a detailed description of domains. 1250 1251For example, the binding for the OpenPIC interrupt controller 1252specifies an #interrupt-cells value of 2 to encode the interrupt 1253number and level/sense information. All interrupt children in an 1254OpenPIC interrupt domain use 2 cells per interrupt in their interrupts 1255property. 1256 1257The PCI bus binding specifies a #interrupt-cell value of 1 to encode 1258which interrupt pin (INTA,INTB,INTC,INTD) is used. 1259 12602) interrupt-parent property 1261---------------------------- 1262 1263The interrupt-parent property is specified to define an explicit 1264link between a device node and its interrupt parent in 1265the interrupt tree. The value of interrupt-parent is the 1266phandle of the parent node. 1267 1268If the interrupt-parent property is not defined for a node, its 1269interrupt parent is assumed to be an ancestor in the node's 1270_device tree_ hierarchy. 1271 12723) OpenPIC Interrupt Controllers 1273-------------------------------- 1274 1275OpenPIC interrupt controllers require 2 cells to encode 1276interrupt information. The first cell defines the interrupt 1277number. The second cell defines the sense and level 1278information. 1279 1280Sense and level information should be encoded as follows: 1281 1282 0 = low to high edge sensitive type enabled 1283 1 = active low level sensitive type enabled 1284 2 = active high level sensitive type enabled 1285 3 = high to low edge sensitive type enabled 1286 12874) ISA Interrupt Controllers 1288---------------------------- 1289 1290ISA PIC interrupt controllers require 2 cells to encode 1291interrupt information. The first cell defines the interrupt 1292number. The second cell defines the sense and level 1293information. 1294 1295ISA PIC interrupt controllers should adhere to the ISA PIC 1296encodings listed below: 1297 1298 0 = active low level sensitive type enabled 1299 1 = active high level sensitive type enabled 1300 2 = high to low edge sensitive type enabled 1301 3 = low to high edge sensitive type enabled 1302 1303VIII - Specifying Device Power Management Information (sleep property) 1304=================================================================== 1305 1306Devices on SOCs often have mechanisms for placing devices into low-power 1307states that are decoupled from the devices' own register blocks. Sometimes, 1308this information is more complicated than a cell-index property can 1309reasonably describe. Thus, each device controlled in such a manner 1310may contain a "sleep" property which describes these connections. 1311 1312The sleep property consists of one or more sleep resources, each of 1313which consists of a phandle to a sleep controller, followed by a 1314controller-specific sleep specifier of zero or more cells. 1315 1316The semantics of what type of low power modes are possible are defined 1317by the sleep controller. Some examples of the types of low power modes 1318that may be supported are: 1319 1320 - Dynamic: The device may be disabled or enabled at any time. 1321 - System Suspend: The device may request to be disabled or remain 1322 awake during system suspend, but will not be disabled until then. 1323 - Permanent: The device is disabled permanently (until the next hard 1324 reset). 1325 1326Some devices may share a clock domain with each other, such that they should 1327only be suspended when none of the devices are in use. Where reasonable, 1328such nodes should be placed on a virtual bus, where the bus has the sleep 1329property. If the clock domain is shared among devices that cannot be 1330reasonably grouped in this manner, then create a virtual sleep controller 1331(similar to an interrupt nexus, except that defining a standardized 1332sleep-map should wait until its necessity is demonstrated). 1333 1334Appendix A - Sample SOC node for MPC8540 1335======================================== 1336 1337 soc@e0000000 { 1338 #address-cells = <1>; 1339 #size-cells = <1>; 1340 compatible = "fsl,mpc8540-ccsr", "simple-bus"; 1341 device_type = "soc"; 1342 ranges = <0x00000000 0xe0000000 0x00100000> 1343 bus-frequency = <0>; 1344 interrupt-parent = <&pic>; 1345 1346 ethernet@24000 { 1347 #address-cells = <1>; 1348 #size-cells = <1>; 1349 device_type = "network"; 1350 model = "TSEC"; 1351 compatible = "gianfar", "simple-bus"; 1352 reg = <0x24000 0x1000>; 1353 local-mac-address = [ 00 E0 0C 00 73 00 ]; 1354 interrupts = <29 2 30 2 34 2>; 1355 phy-handle = <&phy0>; 1356 sleep = <&pmc 00000080>; 1357 ranges; 1358 1359 mdio@24520 { 1360 reg = <0x24520 0x20>; 1361 compatible = "fsl,gianfar-mdio"; 1362 1363 phy0: ethernet-phy@0 { 1364 interrupts = <5 1>; 1365 reg = <0>; 1366 device_type = "ethernet-phy"; 1367 }; 1368 1369 phy1: ethernet-phy@1 { 1370 interrupts = <5 1>; 1371 reg = <1>; 1372 device_type = "ethernet-phy"; 1373 }; 1374 1375 phy3: ethernet-phy@3 { 1376 interrupts = <7 1>; 1377 reg = <3>; 1378 device_type = "ethernet-phy"; 1379 }; 1380 }; 1381 }; 1382 1383 ethernet@25000 { 1384 device_type = "network"; 1385 model = "TSEC"; 1386 compatible = "gianfar"; 1387 reg = <0x25000 0x1000>; 1388 local-mac-address = [ 00 E0 0C 00 73 01 ]; 1389 interrupts = <13 2 14 2 18 2>; 1390 phy-handle = <&phy1>; 1391 sleep = <&pmc 00000040>; 1392 }; 1393 1394 ethernet@26000 { 1395 device_type = "network"; 1396 model = "FEC"; 1397 compatible = "gianfar"; 1398 reg = <0x26000 0x1000>; 1399 local-mac-address = [ 00 E0 0C 00 73 02 ]; 1400 interrupts = <41 2>; 1401 phy-handle = <&phy3>; 1402 sleep = <&pmc 00000020>; 1403 }; 1404 1405 serial@4500 { 1406 #address-cells = <1>; 1407 #size-cells = <1>; 1408 compatible = "fsl,mpc8540-duart", "simple-bus"; 1409 sleep = <&pmc 00000002>; 1410 ranges; 1411 1412 serial@4500 { 1413 device_type = "serial"; 1414 compatible = "ns16550"; 1415 reg = <0x4500 0x100>; 1416 clock-frequency = <0>; 1417 interrupts = <42 2>; 1418 }; 1419 1420 serial@4600 { 1421 device_type = "serial"; 1422 compatible = "ns16550"; 1423 reg = <0x4600 0x100>; 1424 clock-frequency = <0>; 1425 interrupts = <42 2>; 1426 }; 1427 }; 1428 1429 pic: pic@40000 { 1430 interrupt-controller; 1431 #address-cells = <0>; 1432 #interrupt-cells = <2>; 1433 reg = <0x40000 0x40000>; 1434 compatible = "chrp,open-pic"; 1435 device_type = "open-pic"; 1436 }; 1437 1438 i2c@3000 { 1439 interrupts = <43 2>; 1440 reg = <0x3000 0x100>; 1441 compatible = "fsl-i2c"; 1442 dfsrr; 1443 sleep = <&pmc 00000004>; 1444 }; 1445 1446 pmc: power@e0070 { 1447 compatible = "fsl,mpc8540-pmc", "fsl,mpc8548-pmc"; 1448 reg = <0xe0070 0x20>; 1449 }; 1450 }; 1451