From: Ezequiel García Date: Thu, 11 Sep 2014 15:02:08 +0000 (-0300) Subject: nand: omap2: Add support for flash-based bad block table X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=fef775caa705255358cdf7bbaf9bbc2fd1111761;p=openwrt%2Fstaging%2Fblogic.git nand: omap2: Add support for flash-based bad block table This commit adds a new platform-data boolean property that enables use of a flash-based bad block table. This can also be enabled by setting the 'nand-on-flash-bbt' devicetree property. If the flash BBT is not enabled, the driver falls back to use OOB bad block markers only, as before. If the flash BBT is enabled the kernel will keep track of bad blocks using a BBT, in addition to the OOB markers. As explained by Brian Norris the reasons for using a BBT are: "" The primary reason would be that NAND datasheets specify it these days. A better argument is that nobody guarantees that you can write a bad block marker to a worn out block; you may just get program failures. This has been acknowledged by several developers over the last several years. Additionally, you get a boot-time performance improvement if you only have to read a few pages, instead of a page or two from every block on the flash. "" Signed-off-by: Ezequiel Garcia Acked-by: Roger Quadros Signed-off-by: Brian Norris --- diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c index 2f97228f188a..b55a225387cd 100644 --- a/arch/arm/mach-omap2/gpmc.c +++ b/arch/arm/mach-omap2/gpmc.c @@ -1440,6 +1440,8 @@ static int gpmc_probe_nand_child(struct platform_device *pdev, break; } + gpmc_nand_data->flash_bbt = of_get_nand_on_flash_bbt(child); + val = of_get_nand_bus_width(child); if (val == 16) gpmc_nand_data->devsize = NAND_BUSWIDTH_16; diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c index 5967b385141b..e1a9b310c159 100644 --- a/drivers/mtd/nand/omap2.c +++ b/drivers/mtd/nand/omap2.c @@ -1663,7 +1663,6 @@ static int omap_nand_probe(struct platform_device *pdev) mtd->owner = THIS_MODULE; nand_chip = &info->nand; nand_chip->ecc.priv = NULL; - nand_chip->options |= NAND_SKIP_BBTSCAN; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); nand_chip->IO_ADDR_R = devm_ioremap_resource(&pdev->dev, res); @@ -1692,6 +1691,11 @@ static int omap_nand_probe(struct platform_device *pdev) nand_chip->chip_delay = 50; } + if (pdata->flash_bbt) + nand_chip->bbt_options |= NAND_BBT_USE_FLASH | NAND_BBT_NO_OOB; + else + nand_chip->options |= NAND_SKIP_BBTSCAN; + /* scan NAND device connected to chip controller */ nand_chip->options |= pdata->devsize & NAND_BUSWIDTH_16; if (nand_scan_ident(mtd, 1, NULL)) { diff --git a/include/linux/platform_data/mtd-nand-omap2.h b/include/linux/platform_data/mtd-nand-omap2.h index 16ec262dfcc8..090bbab0130a 100644 --- a/include/linux/platform_data/mtd-nand-omap2.h +++ b/include/linux/platform_data/mtd-nand-omap2.h @@ -71,6 +71,7 @@ struct omap_nand_platform_data { struct mtd_partition *parts; int nr_parts; bool dev_ready; + bool flash_bbt; enum nand_io xfer_type; int devsize; enum omap_ecc ecc_opt;