From 9d2ee0a60b8bd9bef2a0082c533736d6a7b39873 Mon Sep 17 00:00:00 2001 From: Kamal Dasu Date: Fri, 3 Mar 2017 16:16:53 -0500 Subject: [PATCH] mtd: nand: brcmnand: Check flash #WP pin status before nand erase/program On brcmnand controller v6.x and v7.x, the #WP pin is controlled through the NAND_WP bit in CS_SELECT register. The driver currently assumes that toggling the #WP pin is instantaneously enabling/disabling write-protection, but it actually takes some time to propagate the new state to the internal NAND chip logic. This behavior is sometime causing data corruptions when an erase/program operation is executed before write-protection has really been disabled. Fixes: 27c5b17cd1b1 ("mtd: nand: add NAND driver "library" for Broadcom STB NAND controller") Signed-off-by: Kamal Dasu Signed-off-by: Boris Brezillon --- drivers/mtd/nand/brcmnand/brcmnand.c | 61 ++++++++++++++++++++++++++-- 1 file changed, 58 insertions(+), 3 deletions(-) diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c index 42ebd73f821d..7419c5ce63f8 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 NAND_CTRL_RDY (INTFC_CTLR_READY | INTFC_FLASH_READY) +#define NAND_POLL_STATUS_TIMEOUT_MS 100 + /* Controller feature flags */ enum { BRCMNAND_HAS_1K_SECTORS = BIT(0), @@ -765,6 +768,31 @@ enum { CS_SELECT_AUTO_DEVICE_ID_CFG = BIT(30), }; +static int bcmnand_ctrl_poll_status(struct brcmnand_controller *ctrl, + u32 mask, u32 expected_val, + unsigned long timeout_ms) +{ + unsigned long limit; + u32 val; + + if (!timeout_ms) + timeout_ms = NAND_POLL_STATUS_TIMEOUT_MS; + + limit = jiffies + msecs_to_jiffies(timeout_ms); + do { + val = brcmnand_read_reg(ctrl, BRCMNAND_INTFC_STATUS); + if ((val & mask) == expected_val) + return 0; + + cpu_relax(); + } while (time_after(limit, jiffies)); + + dev_warn(ctrl->dev, "timeout on status poll (expected %x got %x)\n", + expected_val, val & mask); + + return -ETIMEDOUT; +} + static inline void brcmnand_set_wp(struct brcmnand_controller *ctrl, bool en) { u32 val = en ? CS_SELECT_NAND_WP : 0; @@ -1024,12 +1052,39 @@ static void brcmnand_wp(struct mtd_info *mtd, int wp) if ((ctrl->features & BRCMNAND_HAS_WP) && wp_on == 1) { static int old_wp = -1; + int ret; if (old_wp != wp) { dev_dbg(ctrl->dev, "WP %s\n", wp ? "on" : "off"); old_wp = wp; } + + /* + * make sure ctrl/flash ready before and after + * changing state of #WP pin + */ + ret = bcmnand_ctrl_poll_status(ctrl, NAND_CTRL_RDY | + NAND_STATUS_READY, + NAND_CTRL_RDY | + NAND_STATUS_READY, 0); + if (ret) + return; + brcmnand_set_wp(ctrl, wp); + chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1); + /* NAND_STATUS_WP 0x00 = protected, 0x80 = not protected */ + ret = bcmnand_ctrl_poll_status(ctrl, + NAND_CTRL_RDY | + NAND_STATUS_READY | + NAND_STATUS_WP, + NAND_CTRL_RDY | + NAND_STATUS_READY | + (wp ? 0 : NAND_STATUS_WP), 0); + + if (ret) + dev_err_ratelimited(&host->pdev->dev, + "nand #WP expected %s\n", + wp ? "on" : "off"); } } @@ -1157,15 +1212,15 @@ static irqreturn_t brcmnand_dma_irq(int irq, void *data) static void brcmnand_send_cmd(struct brcmnand_host *host, int cmd) { struct brcmnand_controller *ctrl = host->ctrl; - u32 intfc; + int ret; dev_dbg(ctrl->dev, "send native cmd %d addr_lo 0x%x\n", cmd, brcmnand_read_reg(ctrl, BRCMNAND_CMD_ADDRESS)); BUG_ON(ctrl->cmd_pending != 0); ctrl->cmd_pending = cmd; - intfc = brcmnand_read_reg(ctrl, BRCMNAND_INTFC_STATUS); - WARN_ON(!(intfc & INTFC_CTLR_READY)); + ret = bcmnand_ctrl_poll_status(ctrl, NAND_CTRL_RDY, NAND_CTRL_RDY, 0); + WARN_ON(ret); mb(); /* flush previous writes */ brcmnand_write_reg(ctrl, BRCMNAND_CMD_START, -- 2.20.1