[PATCH 3.10 40/46] mei: me: fix hw ready reset flow

Greg Kroah-Hartman
2014-07-04T22:25:03Z

From: Tomas Winkler <tomas.winkler@intel.com>

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@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/misc/mei/hw-me.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

--- 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(stru
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.
@@ -214,6 +217,7 @@ static void mei_me_hw_reset(struct mei_d
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);
}
@@ -506,19 +510,15 @@ irqreturn_t mei_me_irq_thread_handler(in
/* 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;
wake_up_interruptible(&dev->wait_hw_ready);
-
- mutex_unlock(&dev->device_lock);
- return IRQ_HANDLED;
} else {
- dev_dbg(&dev->pdev->dev, "Reset Completed.\n");
- mei_me_hw_reset_release(dev);
- mutex_unlock(&dev->device_lock);
- return IRQ_HANDLED;
+ dev_dbg(&dev->pdev->dev, "Spurious Interrupt\n");
}
+ goto end;
}
/* check slots available for reading */
slots = mei_count_full_read_slots(dev);