From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr0-x241.google.com ([2a00:1450:400c:c0c::241]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1ceR6l-0000Dk-PH for linux-mtd@lists.infradead.org; Thu, 16 Feb 2017 18:48:53 +0000 Received: by mail-wr0-x241.google.com with SMTP id z61so2324979wrc.3 for ; Thu, 16 Feb 2017 10:48:27 -0800 (PST) From: Kamal Dasu To: linux-mtd@lists.infradead.org Cc: f.fainelli@gmail.com, bcm-kernel-feedback-list@broadcom.com, dwmw2@infradead.org, computersforpeace@gmail.com, boris.brezillon@free-electrons.com, marek.vasut@gmail.com, richard@nod.at, cyrille.pitchen@atmel.com, Kamal Dasu Subject: [PATCH V2, 2/2] mtd: nand: brcmnand: Check flash #WP pin status before nand erase/program Date: Thu, 16 Feb 2017 13:46:52 -0500 Message-Id: <1487270812-6882-2-git-send-email-kdasu.kdev@gmail.com> In-Reply-To: <1487270812-6882-1-git-send-email-kdasu.kdev@gmail.com> References: <1487270812-6882-1-git-send-email-kdasu.kdev@gmail.com> List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , brcmnand controller v6.x and v7.x lets driver to enable disable #WP pin via NAND_WP bit in CS_SELECT register. Driver implementation assumes that setting/resetting the bit would assert/de-assert #WP pin instantaneously from the flash part's perspective, and was proceeding to erase/program without verifying flash status byte for protection bit. In rigorous testing this was causing rare data corruptions with erase and/or subsequent programming. To fix this added verification logic to brcmandn_wp_set() by reading flash status and verifying protection bit indicating #WP pin status. The new logic makes sure controller as well as the flash is ready to accept commands. Signed-off-by: Kamal Dasu --- drivers/mtd/nand/brcmnand/brcmnand.c | 53 ++++++++++++++++++++++++++++++++++-- 1 file changed, 51 insertions(+), 2 deletions(-) diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c index c7c4efe..2f082a3 100644 --- a/drivers/mtd/nand/brcmnand/brcmnand.c +++ b/drivers/mtd/nand/brcmnand/brcmnand.c @@ -101,6 +101,9 @@ struct brcm_nand_dma_desc { #define BRCMNAND_MIN_BLOCKSIZE (8 * 1024) #define BRCMNAND_MIN_DEVSIZE (4ULL * 1024 * 1024) +#define FLASH_RDY (NAND_STATUS_READY) +#define NAND_CTRL_RDY (INTFC_CTLR_READY | INTFC_FLASH_READY) + /* Controller feature flags */ enum { BRCMNAND_HAS_1K_SECTORS = BIT(0), @@ -765,12 +768,57 @@ enum { CS_SELECT_AUTO_DEVICE_ID_CFG = BIT(30), }; -static int brcmnand_set_wp(struct brcmnand_host *host, int en) +static void bcmnand_ctrl_busy_poll(struct brcmnand_controller *ctrl, u32 mask) +{ + unsigned long timeout = jiffies + msecs_to_jiffies(200); + + while ((brcmnand_read_reg(ctrl, BRCMNAND_INTFC_STATUS) & mask) != + mask) { + if (time_after(jiffies, timeout)) { + dev_warn(ctrl->dev, "timeout on ctrl_ready\n"); + break; + } + cpu_relax(); + } +} + +static inline void brcmnand_set_wp_reg(struct brcmnand_controller *ctrl, int en) { - struct brcmnand_controller *ctrl = host->ctrl; u32 val = en ? CS_SELECT_NAND_WP : 0; brcmnand_rmw_reg(ctrl, BRCMNAND_CS_SELECT, CS_SELECT_NAND_WP, 0, val); +} + +static int brcmnand_set_wp(struct brcmnand_host *host, int en) +{ + struct brcmnand_controller *ctrl = host->ctrl; + struct mtd_info *mtd = nand_to_mtd(&host->chip); + struct nand_chip *chip = mtd_to_nand(mtd); + u32 sts_reg; + bool is_wp; + + /* + * make sure ctrl/flash ready before and after + * changing state of WP PIN + */ + bcmnand_ctrl_busy_poll(ctrl, NAND_CTRL_RDY | FLASH_RDY); + brcmnand_set_wp_reg(ctrl, en); + chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1); + bcmnand_ctrl_busy_poll(ctrl, NAND_CTRL_RDY | FLASH_RDY); + sts_reg = brcmnand_read_reg(ctrl, BRCMNAND_INTFC_STATUS); + /* NAND_STATUS_WP 0x80 = not protected, 0x00 = protected */ + is_wp = (sts_reg & NAND_STATUS_WP) ? false : true; + + if (is_wp != en) { + u32 nand_wp = brcmnand_read_reg(ctrl, BRCMNAND_CS_SELECT); + + nand_wp &= CS_SELECT_NAND_WP; + dev_err_ratelimited(&host->pdev->dev, + "#WP %s sts:0x%x expected %s NAND_WP 0x%x\n", + is_wp ? "On" : "Off", sts_reg & 0xff, + en ? "On" : "Off", nand_wp ? 1 : 0); + return -EINVAL; + } return 0; } @@ -1167,6 +1215,7 @@ static void brcmnand_send_cmd(struct brcmnand_host *host, int cmd) BUG_ON(ctrl->cmd_pending != 0); ctrl->cmd_pending = cmd; + bcmnand_ctrl_busy_poll(ctrl, NAND_CTRL_RDY); intfc = brcmnand_read_reg(ctrl, BRCMNAND_INTFC_STATUS); WARN_ON(!(intfc & INTFC_CTLR_READY)); -- 1.9.1