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authorPekon Gupta <pekon@ti.com>2013-10-24 18:20:17 +0530
committerBrian Norris <computersforpeace@gmail.com>2013-11-06 23:33:07 -0800
commitac65caf514ec3e55e8d3d510ee37f80dd97418fe (patch)
tree68a56895371738d7ce6b3f005bf6bce04beafda2 /Documentation
parentdc525ff4705cee2291b1637a650489aca86ac937 (diff)
ARM: OMAP2+: cleaned-up DT support of various ECC schemes
OMAP NAND driver support multiple ECC scheme, which can used in different flavours, depending on in-build Hardware engines present on SoC. This patch updates following in DT bindings related to sectionion of ecc-schemes - ti,elm-id: replaces elm_id (maintains backward compatibility) - ti,nand-ecc-opts: selection of h/w or s/w implementation of an ecc-scheme depends on ti,elm-id. (supported values ham1, bch4, and bch8) - maintain backward compatibility to deprecated DT bindings (sw, hw, hw-romcode) Below table shows different flavours of ecc-schemes supported by OMAP devices +---------------------------------------+---------------+---------------+ | ECC scheme |ECC calculation|Error detection| +---------------------------------------+---------------+---------------+ |OMAP_ECC_HAM1_CODE_HW |H/W (GPMC) |S/W | +---------------------------------------+---------------+---------------+ |OMAP_ECC_BCH8_CODE_HW_DETECTION_SW |H/W (GPMC) |S/W | |(requires CONFIG_MTD_NAND_ECC_BCH) | | | +---------------------------------------+---------------+---------------+ |OMAP_ECC_BCH8_CODE_HW |H/W (GPMC) |H/W (ELM) | |(requires CONFIG_MTD_NAND_OMAP_BCH && | | | | ti,elm-id in DT) | | | +---------------------------------------+---------------+---------------+ To optimize footprint of omap2-nand driver, selection of some ECC schemes also require enabling following Kconfigs, in addition to setting appropriate DT bindings - Kconfig:CONFIG_MTD_NAND_ECC_BCH error detection done in software - Kconfig:CONFIG_MTD_NAND_OMAP_BCH error detection done by h/w engine Signed-off-by: Pekon Gupta <pekon@ti.com> Reviewed-by: Felipe Balbi <balbi@ti.com> Acked-by: Tony Lindgren <tony@atomide.com> Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/mtd/gpmc-nand.txt8
1 files changed, 6 insertions, 2 deletions
diff --git a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
index df338cb5059c..bfe07e152738 100644
--- a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
+++ b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
@@ -36,8 +36,12 @@ Optional properties:
"prefetch-dma" Prefetch enabled sDMA mode
"prefetch-irq" Prefetch enabled irq mode
- - elm_id: Specifies elm device node. This is required to support BCH
- error correction using ELM module.
+ - elm_id: <deprecated> use "ti,elm-id" instead
+ - ti,elm-id: Specifies phandle of the ELM devicetree node.
+ ELM is an on-chip hardware engine on TI SoC which is used for
+ locating ECC errors for BCHx algorithms. SoC devices which have
+ ELM hardware engines should specify this device node in .dtsi
+ Using ELM for ECC error correction frees some CPU cycles.
For inline partiton table parsing (optional):