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Diffstat (limited to 'kernel/Documentation/devicetree/bindings/mtd/brcm,brcmnand.txt')
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diff --git a/kernel/Documentation/devicetree/bindings/mtd/brcm,brcmnand.txt b/kernel/Documentation/devicetree/bindings/mtd/brcm,brcmnand.txt new file mode 100644 index 000000000..4ff7128ee --- /dev/null +++ b/kernel/Documentation/devicetree/bindings/mtd/brcm,brcmnand.txt @@ -0,0 +1,150 @@ +* Broadcom STB NAND Controller + +The Broadcom Set-Top Box NAND controller supports low-level access to raw NAND +flash chips. It has a memory-mapped register interface for both control +registers and for its data input/output buffer. On some SoCs, this controller is +paired with a custom DMA engine (inventively named "Flash DMA") which supports +basic PROGRAM and READ functions, among other features. + +This controller was originally designed for STB SoCs (BCM7xxx) but is now +available on a variety of Broadcom SoCs, including some BCM3xxx, BCM63xx, and +iProc/Cygnus. Its history includes several similar (but not fully register +compatible) versions. + +Required properties: +- compatible : May contain an SoC-specific compatibility string (see below) + to account for any SoC-specific hardware bits that may be + added on top of the base core controller. + In addition, must contain compatibility information about + the core NAND controller, of the following form: + "brcm,brcmnand" and an appropriate version compatibility + string, like "brcm,brcmnand-v7.0" + Possible values: + brcm,brcmnand-v4.0 + brcm,brcmnand-v5.0 + brcm,brcmnand-v6.0 + brcm,brcmnand-v6.1 + brcm,brcmnand-v7.0 + brcm,brcmnand-v7.1 + brcm,brcmnand +- reg : the register start and length for NAND register region. + (optional) Flash DMA register range (if present) + (optional) NAND flash cache range (if at non-standard offset) +- reg-names : a list of the names corresponding to the previous register + ranges. Should contain "nand" and (optionally) + "flash-dma" and/or "nand-cache". +- interrupts : The NAND CTLRDY interrupt and (if Flash DMA is available) + FLASH_DMA_DONE +- interrupt-names : May be "nand_ctlrdy" or "flash_dma_done", if broken out as + individual interrupts. + May be "nand", if the SoC has the individual NAND + interrupts multiplexed behind another custom piece of + hardware +- interrupt-parent : See standard interrupt bindings +- #address-cells : <1> - subnodes give the chip-select number +- #size-cells : <0> + +Optional properties: +- brcm,nand-has-wp : Some versions of this IP include a write-protect + (WP) control bit. It is always available on >= + v7.0. Use this property to describe the rare + earlier versions of this core that include WP + + -- Additonal SoC-specific NAND controller properties -- + +The NAND controller is integrated differently on the variety of SoCs on which it +is found. Part of this integration involves providing status and enable bits +with which to control the 8 exposed NAND interrupts, as well as hardware for +configuring the endianness of the data bus. On some SoCs, these features are +handled via standard, modular components (e.g., their interrupts look like a +normal IRQ chip), but on others, they are controlled in unique and interesting +ways, sometimes with registers that lump multiple NAND-related functions +together. The former case can be described simply by the standard interrupts +properties in the main controller node. But for the latter exceptional cases, +we define additional 'compatible' properties and associated register resources within the NAND controller node above. + + - compatible: Can be one of several SoC-specific strings. Each SoC may have + different requirements for its additional properties, as described below each + bullet point below. + + * "brcm,nand-bcm63138" + - reg: (required) the 'NAND_INT_BASE' register range, with separate status + and enable registers + - reg-names: (required) "nand-int-base" + + * "brcm,nand-iproc" + - reg: (required) the "IDM" register range, for interrupt enable and APB + bus access endianness configuration, and the "EXT" register range, + for interrupt status/ack. + - reg-names: (required) a list of the names corresponding to the previous + register ranges. Should contain "iproc-idm" and "iproc-ext". + + +* NAND chip-select + +Each controller (compatible: "brcm,brcmnand") may contain one or more subnodes +to represent enabled chip-selects which (may) contain NAND flash chips. Their +properties are as follows. + +Required properties: +- compatible : should contain "brcm,nandcs" +- reg : a single integer representing the chip-select + number (e.g., 0, 1, 2, etc.) +- #address-cells : see partition.txt +- #size-cells : see partition.txt +- nand-ecc-strength : see nand.txt +- nand-ecc-step-size : must be 512 or 1024. See nand.txt + +Optional properties: +- nand-on-flash-bbt : boolean, to enable the on-flash BBT for this + chip-select. See nand.txt +- brcm,nand-oob-sector-size : integer, to denote the spare area sector size + expected for the ECC layout in use. This size, in + addition to the strength and step-size, + determines how the hardware BCH engine will lay + out the parity bytes it stores on the flash. + This property can be automatically determined by + the flash geometry (particularly the NAND page + and OOB size) in many cases, but when booting + from NAND, the boot controller has only a limited + number of available options for its default ECC + layout. + +Each nandcs device node may optionally contain sub-nodes describing the flash +partition mapping. See partition.txt for more detail. + + +Example: + +nand@f0442800 { + compatible = "brcm,brcmnand-v7.0", "brcm,brcmnand"; + reg = <0xF0442800 0x600>, + <0xF0443000 0x100>; + reg-names = "nand", "flash-dma"; + interrupt-parent = <&hif_intr2_intc>; + interrupts = <24>, <4>; + + #address-cells = <1>; + #size-cells = <0>; + + nandcs@1 { + compatible = "brcm,nandcs"; + reg = <1>; // Chip select 1 + nand-on-flash-bbt; + nand-ecc-strength = <12>; + nand-ecc-step-size = <512>; + + // Partitions + #address-cells = <1>; // <2>, for 64-bit offset + #size-cells = <1>; // <2>, for 64-bit length + flash0.rootfs@0 { + reg = <0 0x10000000>; + }; + flash0@0 { + reg = <0 0>; // MTDPART_SIZ_FULL + }; + flash0.kernel@10000000 { + reg = <0x10000000 0x400000>; + }; + }; +}; |