From e35d1d8a1d16e9f56a9b54c96d0cb85ed621bb89 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Uwe=20Kleine-K=C3=B6nig?= Date: Tue, 10 Feb 2015 19:59:55 +0100 Subject: [PATCH] mtd: mxc-nand: Add a timeout when waiting for interrupt MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit While extending the mxc-nand driver it happend to me a few times that the device was stuck and this made the machine hang during boot. So implement a timeout and print a stack trace the first time this happens to make it debuggable. The return type of the waiting function is also changed to int to be able to handle the timeout in the caller. Signed-off-by: Uwe Kleine-König Signed-off-by: Brian Norris --- drivers/mtd/nand/mxc_nand.c | 47 ++++++++++++++++++++++++++++++++++----------- 1 file changed, 36 insertions(+), 11 deletions(-) diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c index a8f550f..27ba07c 100644 --- a/drivers/mtd/nand/mxc_nand.c +++ b/drivers/mtd/nand/mxc_nand.c @@ -386,26 +386,51 @@ static irqreturn_t mxc_nfc_irq(int irq, void *dev_id) /* This function polls the NANDFC to wait for the basic operation to * complete by checking the INT bit of config2 register. */ -static void wait_op_done(struct mxc_nand_host *host, int useirq) +static int wait_op_done(struct mxc_nand_host *host, int useirq) { - int max_retries = 8000; + int ret = 0; + + /* + * If operation is already complete, don't bother to setup an irq or a + * loop. + */ + if (host->devtype_data->check_int(host)) + return 0; if (useirq) { - if (!host->devtype_data->check_int(host)) { - reinit_completion(&host->op_completion); - irq_control(host, 1); - wait_for_completion(&host->op_completion); + unsigned long timeout; + + reinit_completion(&host->op_completion); + + irq_control(host, 1); + + timeout = wait_for_completion_timeout(&host->op_completion, HZ); + if (!timeout && !host->devtype_data->check_int(host)) { + dev_dbg(host->dev, "timeout waiting for irq\n"); + ret = -ETIMEDOUT; } } else { - while (max_retries-- > 0) { - if (host->devtype_data->check_int(host)) - break; + int max_retries = 8000; + int done; + do { udelay(1); + + done = host->devtype_data->check_int(host); + if (done) + break; + + } while (--max_retries); + + if (!done) { + dev_dbg(host->dev, "timeout polling for completion\n"); + ret = -ETIMEDOUT; } - if (max_retries < 0) - pr_debug("%s: INT not set\n", __func__); } + + WARN_ONCE(ret < 0, "timeout! useirq=%d\n", useirq); + + return ret; } static void send_cmd_v3(struct mxc_nand_host *host, uint16_t cmd, int useirq) -- 2.7.4