[3.13.y.z extended stable] Patch "mei: me: fix hw ready reset flow" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    mei: me: fix hw ready reset flow

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.5.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From b55b21c729a2113e4141dab56ba787ec3aacd050 Mon Sep 17 00:00:00 2001
From: Tomas Winkler <tomas.winkler at intel.com>
Date: Mon, 12 May 2014 12:19:39 +0300
Subject: mei: me: fix hw ready reset flow

commit b04ada92ffaabb868497a1fce8e4f6bf74e5488f upstream.

We cleared H_RST for H_CSR on spurious interrupt generated when ME_RDY
while cleared and not while  ME_RDY is set. The spurious interrupt
is not delivered on all platforms in this case the
driver may fail to initialize.

Signed-off-by: Tomas Winkler <tomas.winkler at intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin at intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
[ kamal: backport to 3.13-stable: context ]
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/misc/mei/hw-me.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/mei/hw-me.c b/drivers/misc/mei/hw-me.c
index 3412adc..f285dc1 100644
--- a/drivers/misc/mei/hw-me.c
+++ b/drivers/misc/mei/hw-me.c
@@ -164,6 +164,9 @@ static void mei_me_hw_reset_release(struct mei_device *dev)
 	hcsr |= H_IG;
 	hcsr &= ~H_RST;
 	mei_hcsr_set(hw, hcsr);
+
+	/* complete this write before we set host ready on another CPU */
+	mmiowb();
 }
 /**
  * mei_me_hw_reset - resets fw via mei csr register.
@@ -201,6 +204,7 @@ static int mei_me_hw_reset(struct mei_device *dev, bool intr_enable)
 static void mei_me_host_set_ready(struct mei_device *dev)
 {
 	struct mei_me_hw *hw = to_me_hw(dev);
+	hw->host_hw_state = mei_hcsr_read(hw);
 	hw->host_hw_state |= H_IE | H_IG | H_RDY;
 	mei_hcsr_set(hw, hw->host_hw_state);
 }
@@ -496,6 +500,7 @@ irqreturn_t mei_me_irq_thread_handler(int irq, void *dev_id)
 	/*  check if we need to start the dev */
 	if (!mei_host_is_ready(dev)) {
 		if (mei_hw_is_ready(dev)) {
+			mei_me_hw_reset_release(dev);
 			dev_dbg(&dev->pdev->dev, "we need to start the dev.\n");

 			dev->recvd_hw_ready = true;
@@ -504,8 +509,7 @@ irqreturn_t mei_me_irq_thread_handler(int irq, void *dev_id)
 			mutex_unlock(&dev->device_lock);
 			return IRQ_HANDLED;
 		} else {
-			dev_dbg(&dev->pdev->dev, "Reset Completed.\n");
-			mei_me_hw_reset_release(dev);
+			dev_dbg(&dev->pdev->dev, "Spurious Interrupt\n");
 			mutex_unlock(&dev->device_lock);
 			return IRQ_HANDLED;
 		}
--
1.9.1