On Fri, Oct 11, 2013 at 07:06:39PM +0530, Pekon Gupta wrote:
> OMAP NAND driver support multiple ECC scheme, which can used in following
> different flavours, depending on in-build Hardware engines supported by SoC.
>
> +---------------------------------------+---------------+---------------+
> | 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
>
> DT binding updates in this patch are:
> - ti,elm-id: replaces elm_id
> - ti,nand-ecc-opts: supported values ham1, bch4, and bch8
> selection of h/w or s/w implementation depends on ti,elm-id
>
> Signed-off-by: Pekon Gupta <pekon@xxxxxx>
since this maintains backwards compatibility, I think it should be
alright to apply
Reviewed-by: Felipe Balbi <balbi@xxxxxx>
> ---
> .../devicetree/bindings/mtd/gpmc-nand.txt | 8 +++-
> arch/arm/mach-omap2/gpmc.c | 45 ++++++++++++++++------
> include/linux/platform_data/mtd-nand-omap2.h | 14 +++++--
> 3 files changed, 50 insertions(+), 17 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
> index 25ee232..5e1f31b 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):
>
> diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
> index c9fb353..9473c9f 100644
> --- a/arch/arm/mach-omap2/gpmc.c
> +++ b/arch/arm/mach-omap2/gpmc.c
> @@ -1341,12 +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_HAM1_CODE_HW] = "ham1",
> - [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",
> @@ -1376,12 +1370,39 @@ 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 NAND ecc-opt */
> + 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__);
>
> if (!of_property_read_string(child, "ti,nand-xfer-type", &s))
> for (val = 0; val < ARRAY_SIZE(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 cb5a54a..4da5bfa 100644
> --- a/include/linux/platform_data/mtd-nand-omap2.h
> +++ b/include/linux/platform_data/mtd-nand-omap2.h
> @@ -23,9 +23,16 @@ enum nand_io {
> };
>
> enum omap_ecc {
> - OMAP_ECC_HAM1_CODE_HW = 0, /* 1-bit Hamming ecc code */
> - 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 = 0,
> + /* 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 {
> @@ -59,5 +66,6 @@ struct omap_nand_platform_data {
>
> /* for passing the partitions */
> struct device_node *of_node;
> + struct device_node *elm_of_node;
> };
> #endif
> --
> 1.8.1
>
--
balbi
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