diff mbox

[v2,09/13] i2c: designware-baytrail: Acquire P-Unit access on bus acquire

Message ID 20170123210958.18410-10-hdegoede@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Hans de Goede Jan. 23, 2017, 9:09 p.m. UTC
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>
---
Changes in v2:
-Spelling: P-Unit, PMIC
-Adjust for iosf_mbi_punit_lock/_unlock to _acquire/_release rename
---
 drivers/i2c/busses/i2c-designware-baytrail.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Jarkko Nikula Jan. 27, 2017, 11:29 a.m. UTC | #1
On 01/23/2017 11:09 PM, Hans de Goede wrote:
> 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>
> ---
> Changes in v2:
> -Spelling: P-Unit, PMIC
> -Adjust for iosf_mbi_punit_lock/_unlock to _acquire/_release rename
> ---
>  drivers/i2c/busses/i2c-designware-baytrail.c | 4 ++++
>  1 file changed, 4 insertions(+)
>

Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
diff mbox

Patch

diff --git a/drivers/i2c/busses/i2c-designware-baytrail.c b/drivers/i2c/busses/i2c-designware-baytrail.c
index 3effc9a..7eddc3b 100644
--- a/drivers/i2c/busses/i2c-designware-baytrail.c
+++ b/drivers/i2c/busses/i2c-designware-baytrail.c
@@ -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