From 336d139f8718b1336c9d22f0e462611ae1229850 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 27 Aug 2018 16:01:41 +0900 Subject: [PATCH] mtd: rawnand: denali: do not pass zero maxchips to nand_scan() Commit 49aa76b16676 ("mtd: rawnand: do not execute nand_scan_ident() if maxchips is zero") gave a new meaning for calling nand_scan_ident() with maxchips=0. It is a special usage for some drivers such as docg4, but actually the Denali driver may pass maxchips=0 to nand_scan() when the driver is enabled but no NAND chip is found on the board for some reasons. If nand_scan_with_ids() is called with maxchips=0, nand_scan_ident() is skipped, then nand_set_defaults() is skipped as well. Thus, the driver must set chip->controller beforehand. Otherwise, nand_attach() causes NULL pointer dereference. In fact, the Denali controller knows the number of connected chips before calling nand_scan_ident(); if DEVICE_RESET fails, there is no chip in that chip select. Then, denali_reset_banks() sets the maxchips to the number of detected chips. If no chip is found, maxchips is zero. In this case, there is no point for calling nand_scan() because we know it will fail for sure. Let's make the probe function fail immediately. Fixes: 49aa76b16676 ("mtd: rawnand: do not execute nand_scan_ident() if maxchips is zero") Signed-off-by: Masahiro Yamada Acked-by: Miquel Raynal Signed-off-by: Boris Brezillon --- drivers/mtd/nand/raw/denali.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/mtd/nand/raw/denali.c b/drivers/mtd/nand/raw/denali.c index ca18612c4201..67b2065e7a19 100644 --- a/drivers/mtd/nand/raw/denali.c +++ b/drivers/mtd/nand/raw/denali.c @@ -1338,6 +1338,11 @@ int denali_init(struct denali_nand_info *denali) denali_enable_irq(denali); denali_reset_banks(denali); + if (!denali->max_banks) { + /* Error out earlier if no chip is found for some reasons. */ + ret = -ENODEV; + goto disable_irq; + } denali->active_bank = DENALI_INVALID_BANK;