mei: clean reset bit before reset

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.

Cc: <stable@vger.kernel.org> #3.10+
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/hw-me.c

@@ -234,6 +234,18 @@ 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->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)