From 5378fd56295e4c4b2a0065dff62e002ad93def06 Mon Sep 17 00:00:00 2001 From: Tomas Winkler Date: Mon, 12 May 2014 12:19:39 +0300 Subject: mei: me: fix hw ready reset flow MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Alexander Usyskin Signed-off-by: Greg Kroah-Hartman [ kamal: backport to 3.13-stable: context ] Signed-off-by: Kamal Mostafa BugLink: http://bugs.launchpad.net/bugs/1450813 [ kamal: backport to ubuntu-trusty: context ] Tested-by: Pali Rohár --- drivers/misc/mei/hw-me.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/misc/mei/hw-me.c b/drivers/misc/mei/hw-me.c index c59d87f..cffd72b 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. @@ -226,6 +229,7 @@ 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); } @@ -513,14 +517,13 @@ 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; wake_up_interruptible(&dev->wait_hw_ready); } else { - - dev_dbg(&dev->pdev->dev, "Reset Completed.\n"); - mei_me_hw_reset_release(dev); + dev_dbg(&dev->pdev->dev, "Spurious Interrupt\n"); } goto end; } -- 1.9.1