| * 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-v6.2 |
| brcm,brcmnand-v7.0 |
| brcm,brcmnand-v7.1 |
| brcm,brcmnand-v7.2 |
| 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>; |
| }; |
| }; |
| }; |
