i2c: designware-baytrail: Acquire P-Unit access on bus acquire
authorHans de Goede <hdegoede@redhat.com>
Fri, 10 Feb 2017 10:27:59 +0000 (11:27 +0100)
committerDaniel Vetter <daniel.vetter@ffwll.ch>
Thu, 2 Mar 2017 14:46:35 +0000 (15:46 +0100)
Acquire P-Unit access to stop others from accessing the P-Unit while the
PMIC i2c bus is in use. This is necessary because accessing the P-Unit
from the kernel may result in the P-Unit trying to access the PMIC i2c
bus, which results in a hang when it happens while we own the PMIC i2c
bus semaphore.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=155241
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: tagorereddy <tagore.chandan@gmail.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170210102802.20898-10-hdegoede@redhat.com
drivers/i2c/busses/i2c-designware-baytrail.c

index 3effc9a..7eddc3b 100644 (file)
@@ -62,6 +62,8 @@ static void reset_semaphore(struct dw_i2c_dev *dev)
                dev_err(dev->dev, "iosf failed to reset punit semaphore during write\n");
 
        pm_qos_update_request(&dev->pm_qos, PM_QOS_DEFAULT_VALUE);
+
+       iosf_mbi_punit_release();
 }
 
 static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
@@ -79,6 +81,8 @@ static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
        if (!dev->release_lock)
                return 0;
 
+       iosf_mbi_punit_acquire();
+
        /*
         * Disallow the CPU to enter C6 or C7 state, entering these states
         * requires the punit to talk to the pmic and if this happens while