mei: clean reset bit before reset

commit b13a65ef190e488e2761d65bdd2e1fe8a3a125f5 upstream.

H_RST bit in H_CSR register may be found lit before reset is started,
for example if preceding reset flow hasn't completed.
In that case asserting H_RST will be ignored, therefore we need to clean
H_RST bit to start a successful reset sequence.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ luis: backported to 3.16:
  - replace dev->dev by &dev->pdev->dev ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/drivers/misc/mei/hw-me.c b/drivers/misc/mei/hw-me.c
index 6a2d272cea43fe5f1cdfd3dbb4a7ed9550d3a06c..9d0cd32d885af4c7bfc8577a6f5f3971e6c1bd4d 100644 (file)
--- a/drivers/misc/mei/hw-me.c
+++ b/drivers/misc/mei/hw-me.c
@@ -196,6 +196,18 @@ static int mei_me_hw_reset(struct mei_device *dev, bool intr_enable)
        struct mei_me_hw *hw = to_me_hw(dev);
        u32 hcsr = mei_hcsr_read(hw);
 
+       /* H_RST may be found lit before reset is started,
+        * for example if preceding reset flow hasn't completed.
+        * In that case asserting H_RST will be ignored, therefore
+        * we need to clean H_RST bit to start a successful reset sequence.
+        */
+       if ((hcsr & H_RST) == H_RST) {
+               dev_warn(&dev->pdev->dev, "H_RST is set = 0x%08X", hcsr);
+               hcsr &= ~H_RST;
+               mei_me_reg_write(hw, H_CSR, hcsr);
+               hcsr = mei_hcsr_read(hw);
+       }
+
        hcsr |= H_RST | H_IG | H_IS;
 
        if (intr_enable)