From ac65caf514ec3e55e8d3d510ee37f80dd97418fe Mon Sep 17 00:00:00 2001 From: Pekon Gupta Date: Thu, 24 Oct 2013 18:20:17 +0530 Subject: [PATCH] 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 Reviewed-by: Felipe Balbi Acked-by: Tony Lindgren Tested-by: Ezequiel Garcia Signed-off-by: Brian Norris --- .../devicetree/bindings/mtd/gpmc-nand.txt | 8 +++- arch/arm/mach-omap2/gpmc.c | 48 +++++++++++++------ include/linux/platform_data/mtd-nand-omap2.h | 13 ++++- 3 files changed, 51 insertions(+), 18 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: 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): diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c index 579697adaae7..c877129142ba 100644 --- a/arch/arm/mach-omap2/gpmc.c +++ b/arch/arm/mach-omap2/gpmc.c @@ -1341,14 +1341,6 @@ static void __maybe_unused gpmc_read_timings_dt(struct device_node *np, #ifdef CONFIG_MTD_NAND -static const char * const nand_ecc_opts[] = { - [OMAP_ECC_HAMMING_CODE_DEFAULT] = "sw", - [OMAP_ECC_HAMMING_CODE_HW] = "hw", - [OMAP_ECC_HAMMING_CODE_HW_ROMCODE] = "hw-romcode", - [OMAP_ECC_BCH4_CODE_HW] = "bch4", - [OMAP_ECC_BCH8_CODE_HW] = "bch8", -}; - static const char * const nand_xfer_types[] = { [NAND_OMAP_PREFETCH_POLLED] = "prefetch-polled", [NAND_OMAP_POLLED] = "polled", @@ -1378,13 +1370,41 @@ static int gpmc_probe_nand_child(struct platform_device *pdev, gpmc_nand_data->cs = val; gpmc_nand_data->of_node = child; - if (!of_property_read_string(child, "ti,nand-ecc-opt", &s)) - for (val = 0; val < ARRAY_SIZE(nand_ecc_opts); val++) - if (!strcasecmp(s, nand_ecc_opts[val])) { - gpmc_nand_data->ecc_opt = val; - break; - } + /* Detect availability of ELM module */ + gpmc_nand_data->elm_of_node = of_parse_phandle(child, "ti,elm-id", 0); + if (gpmc_nand_data->elm_of_node == NULL) + gpmc_nand_data->elm_of_node = + of_parse_phandle(child, "elm_id", 0); + if (gpmc_nand_data->elm_of_node == NULL) + pr_warn("%s: ti,elm-id property not found\n", __func__); + + /* select ecc-scheme for NAND */ + if (of_property_read_string(child, "ti,nand-ecc-opt", &s)) { + pr_err("%s: ti,nand-ecc-opt not found\n", __func__); + return -ENODEV; + } + if (!strcmp(s, "ham1") || !strcmp(s, "sw") || + !strcmp(s, "hw") || !strcmp(s, "hw-romcode")) + gpmc_nand_data->ecc_opt = + OMAP_ECC_HAM1_CODE_HW; + else if (!strcmp(s, "bch4")) + if (gpmc_nand_data->elm_of_node) + gpmc_nand_data->ecc_opt = + OMAP_ECC_BCH4_CODE_HW; + else + gpmc_nand_data->ecc_opt = + OMAP_ECC_BCH4_CODE_HW_DETECTION_SW; + else if (!strcmp(s, "bch8")) + if (gpmc_nand_data->elm_of_node) + gpmc_nand_data->ecc_opt = + OMAP_ECC_BCH8_CODE_HW; + else + gpmc_nand_data->ecc_opt = + OMAP_ECC_BCH8_CODE_HW_DETECTION_SW; + else + pr_err("%s: ti,nand-ecc-opt invalid value\n", __func__); + /* select data transfer mode for NAND controller */ if (!of_property_read_string(child, "ti,nand-xfer-type", &s)) for (val = 0; val < ARRAY_SIZE(nand_xfer_types); val++) if (!strcasecmp(s, nand_xfer_types[val])) { diff --git a/include/linux/platform_data/mtd-nand-omap2.h b/include/linux/platform_data/mtd-nand-omap2.h index 6bf9ef43ddb1..e4128f1510bf 100644 --- a/include/linux/platform_data/mtd-nand-omap2.h +++ b/include/linux/platform_data/mtd-nand-omap2.h @@ -28,8 +28,16 @@ enum omap_ecc { OMAP_ECC_HAMMING_CODE_HW, /* gpmc to detect the error */ /* 1-bit ecc: stored at beginning of spare area as romcode */ OMAP_ECC_HAMMING_CODE_HW_ROMCODE, /* gpmc method & romcode layout */ - OMAP_ECC_BCH4_CODE_HW, /* 4-bit BCH ecc code */ - OMAP_ECC_BCH8_CODE_HW, /* 8-bit BCH ecc code */ + /* 1-bit ECC calculation by GPMC, Error detection by Software */ + OMAP_ECC_HAM1_CODE_HW, + /* 4-bit ECC calculation by GPMC, Error detection by Software */ + OMAP_ECC_BCH4_CODE_HW_DETECTION_SW, + /* 4-bit ECC calculation by GPMC, Error detection by ELM */ + OMAP_ECC_BCH4_CODE_HW, + /* 8-bit ECC calculation by GPMC, Error detection by Software */ + OMAP_ECC_BCH8_CODE_HW_DETECTION_SW, + /* 8-bit ECC calculation by GPMC, Error detection by ELM */ + OMAP_ECC_BCH8_CODE_HW, }; struct gpmc_nand_regs { @@ -63,5 +71,6 @@ struct omap_nand_platform_data { /* for passing the partitions */ struct device_node *of_node; + struct device_node *elm_of_node; }; #endif -- 2.20.1