diff options
Diffstat (limited to 'Documentation/powerpc')
| -rw-r--r-- | Documentation/powerpc/booting-without-of.txt | 47 | ||||
| -rw-r--r-- | Documentation/powerpc/mpc52xx-device-tree-bindings.txt | 189 |
2 files changed, 232 insertions, 4 deletions
diff --git a/Documentation/powerpc/booting-without-of.txt b/Documentation/powerpc/booting-without-of.txt index 27b457c09729..b3bd36668db3 100644 --- a/Documentation/powerpc/booting-without-of.txt +++ b/Documentation/powerpc/booting-without-of.txt @@ -6,6 +6,8 @@ IBM Corp. (c) 2005 Becky Bruce <becky.bruce at freescale.com>, Freescale Semiconductor, FSL SOC and 32-bit additions +(c) 2006 MontaVista Software, Inc. + Flash chip node definition May 18, 2005: Rev 0.1 - Initial draft, no chapter III yet. @@ -33,13 +35,13 @@ - Change version 16 format to always align property data to 4 bytes. Since tokens are already aligned, that means no specific - required alignement between property size + required alignment between property size and property data. The old style variable alignment would make it impossible to do "simple" insertion of properties using memove (thanks Milton for noticing). Updated kernel patch as well - - Correct a few more alignement constraints + - Correct a few more alignment constraints - Add a chapter about the device-tree compiler and the textural representation of the tree that can be "compiled" by dtc. @@ -854,7 +856,7 @@ address which can extend beyond that limit. console device if any. Typically, if you have serial devices on your board, you may want to put the full path to the one set as the default console in the firmware here, for the kernel to pick - it up as it's own default console. If you look at the funciton + it up as its own default console. If you look at the function set_preferred_console() in arch/ppc64/kernel/setup.c, you'll see that the kernel tries to find out the default console and has knowledge of various types like 8250 serial ports. You may want @@ -1124,7 +1126,7 @@ should have the following properties: - interrupt-parent : contains the phandle of the interrupt controller which handles interrupts for this device - interrupts : a list of tuples representing the interrupt - number and the interrupt sense and level for each interupt + number and the interrupt sense and level for each interrupt for this device. This information is used by the kernel to build the interrupt table @@ -1693,6 +1695,43 @@ platforms are moved over to use the flattened-device-tree model. }; }; + g) Flash chip nodes + + Flash chips (Memory Technology Devices) are often used for solid state + file systems on embedded devices. + + Required properties: + + - device_type : has to be "rom" + - compatible : Should specify what this ROM device is compatible with + (i.e. "onenand"). Currently, this is most likely to be "direct-mapped" + (which corresponds to the MTD physmap mapping driver). + - regs : Offset and length of the register set (or memory mapping) for + the device. + + Recommended properties : + + - bank-width : Width of the flash data bus in bytes. Required + for the NOR flashes (compatible == "direct-mapped" and others) ONLY. + - partitions : Several pairs of 32-bit values where the first value is + partition's offset from the start of the device and the second one is + partition size in bytes with LSB used to signify a read only + partititon (so, the parition size should always be an even number). + - partition-names : The list of concatenated zero terminated strings + representing the partition names. + + Example: + + flash@ff000000 { + device_type = "rom"; + compatible = "direct-mapped"; + regs = <ff000000 01000000>; + bank-width = <4>; + partitions = <00000000 00f80000 + 00f80000 00080001>; + partition-names = "fs\0firmware"; + }; + More devices will be defined as this spec matures. diff --git a/Documentation/powerpc/mpc52xx-device-tree-bindings.txt b/Documentation/powerpc/mpc52xx-device-tree-bindings.txt new file mode 100644 index 000000000000..d077d764f82b --- /dev/null +++ b/Documentation/powerpc/mpc52xx-device-tree-bindings.txt @@ -0,0 +1,189 @@ +MPC52xx Device Tree Bindings +---------------------------- + +(c) 2006 Secret Lab Technologies Ltd +Grant Likely <grant.likely at secretlab.ca> + +I - Introduction +================ +Boards supported by the arch/powerpc architecture require device tree be +passed by the boot loader to the kernel at boot time. The device tree +describes what devices are present on the board and how they are +connected. The device tree can either be passed as a binary blob (as +described in Documentation/powerpc/booting-without-of.txt), or passed +by Open Firmare (IEEE 1275) compatible firmware using an OF compatible +client interface API. + +This document specifies the requirements on the device-tree for mpc52xx +based boards. These requirements are above and beyond the details +specified in either the OpenFirmware spec or booting-without-of.txt + +All new mpc52xx-based boards are expected to match this document. In +cases where this document is not sufficient to support a new board port, +this document should be updated as part of adding the new board support. + +II - Philosophy +=============== +The core of this document is naming convention. The whole point of +defining this convention is to reduce or eliminate the number of +special cases required to support a 52xx board. If all 52xx boards +follow the same convention, then generic 52xx support code will work +rather than coding special cases for each new board. + +This section tries to capture the thought process behind why the naming +convention is what it is. + +1. Node names +------------- +There is strong convention/requirements already established for children +of the root node. 'cpus' describes the processor cores, 'memory' +describes memory, and 'chosen' provides boot configuration. Other nodes +are added to describe devices attached to the processor local bus. +Following convention already established with other system-on-chip +processors, MPC52xx boards must have an 'soc5200' node as a child of the +root node. + +The soc5200 node holds child nodes for all on chip devices. Child nodes +are typically named after the configured function. ie. the FEC node is +named 'ethernet', and a PSC in uart mode is named 'serial'. + +2. device_type property +----------------------- +similar to the node name convention above; the device_type reflects the +configured function of a device. ie. 'serial' for a uart and 'spi' for +an spi controller. However, while node names *should* reflect the +configured function, device_type *must* match the configured function +exactly. + +3. compatible property +---------------------- +Since device_type isn't enough to match devices to drivers, there also +needs to be a naming convention for the compatible property. Compatible +is an list of device descriptions sorted from specific to generic. For +the mpc52xx, the required format for each compatible value is +<chip>-<device>[-<mode>]. At the minimum, the list shall contain two +items; the first specifying the exact chip, and the second specifying +mpc52xx for the chip. + +ie. ethernet on mpc5200b: compatible = "mpc5200b-ethernet\0mpc52xx-ethernet" + +The idea here is that most drivers will match to the most generic field +in the compatible list (mpc52xx-*), but can also test the more specific +field for enabling bug fixes or extra features. + +Modal devices, like PSCs, also append the configured function to the +end of the compatible field. ie. A PSC in i2s mode would specify +"mpc52xx-psc-i2s", not "mpc52xx-i2s". This convention is chosen to +avoid naming conflicts with non-psc devices providing the same +function. For example, "mpc52xx-spi" and "mpc52xx-psc-spi" describe +the mpc5200 simple spi device and a PSC spi mode respectively. + +If the soc device is more generic and present on other SOCs, the +compatible property can specify the more generic device type also. + +ie. mscan: compatible = "mpc5200-mscan\0mpc52xx-mscan\0fsl,mscan"; + +At the time of writing, exact chip may be either 'mpc5200' or +'mpc5200b'. + +Device drivers should always try to match as generically as possible. + +III - Structure +=============== +The device tree for an mpc52xx board follows the structure defined in +booting-without-of.txt with the following additional notes: + +0) the root node +---------------- +Typical root description node; see booting-without-of + +1) The cpus node +---------------- +The cpus node follows the basic layout described in booting-without-of. +The bus-frequency property holds the XLB bus frequency +The clock-frequency property holds the core frequency + +2) The memory node +------------------ +Typical memory description node; see booting-without-of. + +3) The soc5200 node +------------------- +This node describes the on chip SOC peripherals. Every mpc52xx based +board will have this node, and as such there is a common naming +convention for SOC devices. + +Required properties: +name type description +---- ---- ----------- +device_type string must be "soc" +ranges int should be <0 baseaddr baseaddr+10000> +reg int must be <baseaddr 10000> + +Recommended properties: +name type description +---- ---- ----------- +compatible string should be "<chip>-soc\0mpc52xx-soc" + ie. "mpc5200b-soc\0mpc52xx-soc" +#interrupt-cells int must be <3>. If it is not defined + here then it must be defined in every + soc device node. +bus-frequency int IPB bus frequency in HZ. Clock rate + used by most of the soc devices. + Defining it here avoids needing it + added to every device node. + +4) soc5200 child nodes +---------------------- +Any on chip SOC devices available to Linux must appear as soc5200 child nodes. + +Note: in the tables below, '*' matches all <chip> values. ie. +*-pic would translate to "mpc5200-pic\0mpc52xx-pic" + +Required soc5200 child nodes: +name device_type compatible Description +---- ----------- ---------- ----------- +cdm@<addr> cdm *-cmd Clock Distribution +pic@<addr> interrupt-controller *-pic need an interrupt + controller to boot +bestcomm@<addr> dma-controller *-bestcomm 52xx pic also requires + the bestcomm device + +Recommended soc5200 child nodes; populate as needed for your board +name device_type compatible Description +---- ----------- ---------- ----------- +gpt@<addr> gpt *-gpt General purpose timers +rtc@<addr> rtc *-rtc Real time clock +mscan@<addr> mscan *-mscan CAN bus controller +pci@<addr> pci *-pci PCI bridge +serial@<addr> serial *-psc-uart PSC in serial mode +i2s@<addr> i2s *-psc-i2s PSC in i2s mode +ac97@<addr> ac97 *-psc-ac97 PSC in ac97 mode +spi@<addr> spi *-psc-spi PSC in spi mode +irda@<addr> irda *-psc-irda PSC in IrDA mode +spi@<addr> spi *-spi MPC52xx spi device +ethernet@<addr> network *-fec MPC52xx ethernet device +ata@<addr> ata *-ata IDE ATA interface +i2c@<addr> i2c *-i2c I2C controller +usb@<addr> usb-ohci-be *-ohci,ohci-be USB controller +xlb@<addr> xlb *-xlb XLB arbritrator + +IV - Extra Notes +================ + +1. Interrupt mapping +-------------------- +The mpc52xx pic driver splits hardware IRQ numbers into two levels. The +split reflects the layout of the PIC hardware itself, which groups +interrupts into one of three groups; CRIT, MAIN or PERP. Also, the +Bestcomm dma engine has it's own set of interrupt sources which are +cascaded off of peripheral interrupt 0, which the driver interprets as a +fourth group, SDMA. + +The interrupts property for device nodes using the mpc52xx pic consists +of three cells; <L1 L2 level> + + L1 := [CRIT=0, MAIN=1, PERP=2, SDMA=3] + L2 := interrupt number; directly mapped from the value in the + "ICTL PerStat, MainStat, CritStat Encoded Register" + level := [LEVEL_HIGH=0, EDGE_RISING=1, EDGE_FALLING=2, LEVEL_LOW=3] |