rtc/mc13783: protect rtc {,un}registration by mc13783 lock

This is to protect from interrupt handlers using an unregistered rtc
device.

To assert that the reset irq is considered now before the rtc is
registered the corresponding status is checked before.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Paul Gortmaker <p_gortmaker@yahoo.com>
Cc: Valentin Longchamp <valentin.longchamp@epfl.ch>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Luotao Fu <l.fu@pengutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/rtc/rtc-mc13783.c b/drivers/rtc/rtc-mc13783.c
index 0a978a0e40fce6dcf65bdc3ecf6b9b54b61707d4..6a36201178a865cbf3fcf568a4b07d8883d5d0f8 100644 (file)
--- a/drivers/rtc/rtc-mc13783.c
+++ b/drivers/rtc/rtc-mc13783.c
@@ -169,6 +169,7 @@ static int __devinit mc13783_rtc_probe(struct platform_device *pdev)
 {
        int ret;
        struct mc13783_rtc *priv;
+       int rtcrst_pending;
 
        priv = kzalloc(sizeof(*priv), GFP_KERNEL);
        if (!priv)
@@ -177,8 +178,6 @@ static int __devinit mc13783_rtc_probe(struct platform_device *pdev)
        priv->mc13783 = dev_get_drvdata(pdev->dev.parent);
        platform_set_drvdata(pdev, priv);
 
-       priv->valid = 1;
-
        mc13783_lock(priv->mc13783);
 
        ret = mc13783_irq_request(priv->mc13783, MC13783_IRQ_RTCRST,
@@ -186,33 +185,37 @@ static int __devinit mc13783_rtc_probe(struct platform_device *pdev)
        if (ret)
                goto err_reset_irq_request;
 
+       ret = mc13783_irq_status(priv->mc13783, MC13783_IRQ_RTCRST,
+                       NULL, &rtcrst_pending);
+       if (ret)
+               goto err_reset_irq_status;
+
+       priv->valid = !rtcrst_pending;
+
        ret = mc13783_irq_request_nounmask(priv->mc13783, MC13783_IRQ_1HZ,
                        mc13783_rtc_update_handler, DRIVER_NAME, priv);
        if (ret)
                goto err_update_irq_request;
 
-       mc13783_unlock(priv->mc13783);
-
        priv->rtc = rtc_device_register(pdev->name,
                        &pdev->dev, &mc13783_rtc_ops, THIS_MODULE);
-
        if (IS_ERR(priv->rtc)) {
                ret = PTR_ERR(priv->rtc);
 
-               mc13783_lock(priv->mc13783);
-
                mc13783_irq_free(priv->mc13783, MC13783_IRQ_1HZ, priv);
 err_update_irq_request:
 
+err_reset_irq_status:
+
                mc13783_irq_free(priv->mc13783, MC13783_IRQ_RTCRST, priv);
 err_reset_irq_request:
 
-               mc13783_unlock(priv->mc13783);
-
                platform_set_drvdata(pdev, NULL);
                kfree(priv);
        }
 
+       mc13783_unlock(priv->mc13783);
+
        return ret;
 }
 
@@ -220,10 +223,10 @@ static int __devexit mc13783_rtc_remove(struct platform_device *pdev)
 {
        struct mc13783_rtc *priv = platform_get_drvdata(pdev);
 
-       rtc_device_unregister(priv->rtc);
-
        mc13783_lock(priv->mc13783);
 
+       rtc_device_unregister(priv->rtc);
+
        mc13783_irq_free(priv->mc13783, MC13783_IRQ_1HZ, priv);
        mc13783_irq_free(priv->mc13783, MC13783_IRQ_RTCRST, priv);