From 24669c964c7d495c24ba79824d5498c3ef6a1da4 Mon Sep 17 00:00:00 2001
From: Mika Westerberg <mika.westerberg@linux.intel.com>
Date: Tue, 6 Jun 2017 15:25:15 +0300
Subject: [PATCH 23/34] thunderbolt: Do not touch the hardware if the NHI is
 gone on resume
Git-commit: bdccf295d7cdf6f28ceec1dcc31a79d0a1697d21
Patch-mainline: v4.13
References: FATE#323948

On PCs the NHI host controller is only present when there is a device
connected. When the last device is disconnected the host controller will
dissappear shortly (within 10s). Now if that happens when we are
suspended we should not try to touch the hardware anymore, so add a flag
for this and check it before we re-enable rings.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/thunderbolt/nhi.c | 12 ++++++++++++
 drivers/thunderbolt/nhi.h |  3 +++
 2 files changed, 15 insertions(+)

diff --git a/drivers/thunderbolt/nhi.c b/drivers/thunderbolt/nhi.c
index c358c074f925..14311535661d 100644
--- a/drivers/thunderbolt/nhi.c
+++ b/drivers/thunderbolt/nhi.c
@@ -403,6 +403,8 @@ void ring_start(struct tb_ring *ring)
 {
 	mutex_lock(&ring->nhi->lock);
 	mutex_lock(&ring->lock);
+	if (ring->nhi->going_away)
+		goto err;
 	if (ring->running) {
 		dev_WARN(&ring->nhi->pdev->dev, "ring already started\n");
 		goto err;
@@ -449,6 +451,8 @@ void ring_stop(struct tb_ring *ring)
 	mutex_lock(&ring->lock);
 	dev_info(&ring->nhi->pdev->dev, "stopping %s %d\n",
 		 RING_TYPE(ring), ring->hop);
+	if (ring->nhi->going_away)
+		goto err;
 	if (!ring->running) {
 		dev_WARN(&ring->nhi->pdev->dev, "%s %d already stopped\n",
 			 RING_TYPE(ring), ring->hop);
@@ -653,6 +657,14 @@ static int nhi_resume_noirq(struct device *dev)
 	struct pci_dev *pdev = to_pci_dev(dev);
 	struct tb *tb = pci_get_drvdata(pdev);
 
+	/*
+	 * Check that the device is still there. It may be that the user
+	 * unplugged last device which causes the host controller to go
+	 * away on PCs.
+	 */
+	if (!pci_device_is_present(pdev))
+		tb->nhi->going_away = true;
+
 	return tb_domain_resume_noirq(tb);
 }
 
diff --git a/drivers/thunderbolt/nhi.h b/drivers/thunderbolt/nhi.h
index 446ff6dac91d..953864ae0ab3 100644
--- a/drivers/thunderbolt/nhi.h
+++ b/drivers/thunderbolt/nhi.h
@@ -20,6 +20,8 @@
  * @tx_rings: All Tx rings available on this host controller
  * @rx_rings: All Rx rings available on this host controller
  * @msix_ida: Used to allocate MSI-X vectors for rings
+ * @going_away: The host controller device is about to disappear so when
+ *		this flag is set, avoid touching the hardware anymore.
  * @interrupt_work: Work scheduled to handle ring interrupt when no
  *		    MSI-X is used.
  * @hop_count: Number of rings (end point hops) supported by NHI.
@@ -31,6 +33,7 @@ struct tb_nhi {
 	struct tb_ring **tx_rings;
 	struct tb_ring **rx_rings;
 	struct ida msix_ida;
+	bool going_away;
 	struct work_struct interrupt_work;
 	u32 hop_count;
 };
-- 
2.12.3