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authorThomas Chou <thomas@wytron.com.tw>2015-11-07 14:31:08 +0800
committerThomas Chou <thomas@wytron.com.tw>2015-11-12 08:26:58 +0800
commitf1056910434d87051ff8af80a84e248dd1670abb (patch)
treebf6a6407ffb49e7bc01aa9f1d75cea3961991526 /doc
parentd85879938d3fc3557f6ff74a60f95e0975a314ce (diff)
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talos-obmc-uboot-f1056910434d87051ff8af80a84e248dd1670abb.zip
cfi_flash: convert to driver model
Convert cfi flash to driver model. Signed-off-by: Thomas Chou <thomas@wytron.com.tw> Reviewed-by: Simon Glass <sjg@chromium.org>
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-rw-r--r--doc/device-tree-bindings/mtd/mtd-physmap.txt88
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diff --git a/doc/device-tree-bindings/mtd/mtd-physmap.txt b/doc/device-tree-bindings/mtd/mtd-physmap.txt
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+CFI or JEDEC memory-mapped NOR flash, MTD-RAM (NVRAM...)
+
+Flash chips (Memory Technology Devices) are often used for solid state
+file systems on embedded devices.
+
+ - compatible : should contain the specific model of mtd chip(s)
+ used, if known, followed by either "cfi-flash", "jedec-flash",
+ "mtd-ram" or "mtd-rom".
+ - reg : Address range(s) of the mtd chip(s)
+ It's possible to (optionally) define multiple "reg" tuples so that
+ non-identical chips can be described in one node.
+ - bank-width : Width (in bytes) of the bank. Equal to the
+ device width times the number of interleaved chips.
+ - device-width : (optional) Width of a single mtd chip. If
+ omitted, assumed to be equal to 'bank-width'.
+ - #address-cells, #size-cells : Must be present if the device has
+ sub-nodes representing partitions (see below). In this case
+ both #address-cells and #size-cells must be equal to 1.
+ - no-unaligned-direct-access: boolean to disable the default direct
+ mapping of the flash.
+ On some platforms (e.g. MPC5200) a direct 1:1 mapping may cause
+ problems with JFFS2 usage, as the local bus (LPB) doesn't support
+ unaligned accesses as implemented in the JFFS2 code via memcpy().
+ By defining "no-unaligned-direct-access", the flash will not be
+ exposed directly to the MTD users (e.g. JFFS2) any more.
+ - linux,mtd-name: allow to specify the mtd name for retro capability with
+ physmap-flash drivers as boot loader pass the mtd partition via the old
+ device name physmap-flash.
+ - use-advanced-sector-protection: boolean to enable support for the
+ advanced sector protection (Spansion: PPB - Persistent Protection
+ Bits) locking.
+
+For JEDEC compatible devices, the following additional properties
+are defined:
+
+ - vendor-id : Contains the flash chip's vendor id (1 byte).
+ - device-id : Contains the flash chip's device id (1 byte).
+
+For ROM compatible devices (and ROM fallback from cfi-flash), the following
+additional (optional) property is defined:
+
+ - erase-size : The chip's physical erase block size in bytes.
+
+The device tree may optionally contain sub-nodes describing partitions of the
+address space. See partition.txt for more detail.
+
+Example:
+
+ flash@ff000000 {
+ compatible = "amd,am29lv128ml", "cfi-flash";
+ reg = <ff000000 01000000>;
+ bank-width = <4>;
+ device-width = <1>;
+ #address-cells = <1>;
+ #size-cells = <1>;
+ fs@0 {
+ label = "fs";
+ reg = <0 f80000>;
+ };
+ firmware@f80000 {
+ label ="firmware";
+ reg = <f80000 80000>;
+ read-only;
+ };
+ };
+
+Here an example with multiple "reg" tuples:
+
+ flash@f0000000,0 {
+ #address-cells = <1>;
+ #size-cells = <1>;
+ compatible = "intel,pc48f4400p0vb", "cfi-flash";
+ reg = <0 0x00000000 0x02000000
+ 0 0x02000000 0x02000000>;
+ bank-width = <2>;
+ partition@0 {
+ label = "test-part1";
+ reg = <0 0x04000000>;
+ };
+ };
+
+An example using SRAM:
+
+ sram@2,0 {
+ compatible = "samsung,k6f1616u6a", "mtd-ram";
+ reg = <2 0 0x00200000>;
+ bank-width = <2>;
+ };
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