From fef775caa705255358cdf7bbaf9bbc2fd1111761 Mon Sep 17 00:00:00 2001 From: Ezequiel García Date: Thu, 11 Sep 2014 12:02:08 -0300 Subject: 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 --- drivers/mtd/nand/omap2.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'drivers/mtd') 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)) { -- cgit v1.2.3-58-ga151