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Subject[PATCH 2/4] PCI: hv: Add the support of hibernation
Date
Implement the suspend/resume callbacks for hibernation.

hv_pci_suspend() needs to prevent any new work from being queued: a later
patch will address this issue.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
---
drivers/pci/controller/pci-hyperv.c | 76 +++++++++++++++++++++++++++++++++++++
1 file changed, 76 insertions(+)

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index 03fa039..3b77a3a 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -1398,6 +1398,23 @@ static void prepopulate_bars(struct hv_pcibus_device *hbus)

spin_lock_irqsave(&hbus->device_list_lock, flags);

+ /*
+ * Clear the memory enable bit, in case it's already set. This occurs
+ * in the suspend path of hibernation, where the device is suspended,
+ * resumed and suspended again: see hibernation_snapshot() and
+ * hibernation_platform_enter().
+ *
+ * If the memory enable bit is already set, Hyper-V sliently ignores
+ * the below BAR updates, and the related PCI device driver can not
+ * work, because reading from the device register(s) always returns
+ * 0xFFFFFFFF.
+ */
+ list_for_each_entry(hpdev, &hbus->children, list_entry) {
+ _hv_pcifront_read_config(hpdev, PCI_COMMAND, 2, &command);
+ command &= ~PCI_COMMAND_MEMORY;
+ _hv_pcifront_write_config(hpdev, PCI_COMMAND, 2, command);
+ }
+
/* Pick addresses for the BARs. */
do {
list_for_each_entry(hpdev, &hbus->children, list_entry) {
@@ -2737,6 +2754,63 @@ static int hv_pci_remove(struct hv_device *hdev)
return ret;
}

+static int hv_pci_suspend(struct hv_device *hdev)
+{
+ struct hv_pcibus_device *hbus = hv_get_drvdata(hdev);
+ int ret;
+
+ /* XXX: Need to prevent any new work from being queued. */
+ flush_workqueue(hbus->wq);
+
+ ret = hv_pci_bus_exit(hdev, true);
+ if (ret)
+ return ret;
+
+ vmbus_close(hdev->channel);
+
+ return 0;
+}
+
+static int hv_pci_resume(struct hv_device *hdev)
+{
+ struct hv_pcibus_device *hbus = hv_get_drvdata(hdev);
+ enum pci_protocol_version_t version[1];
+ int ret;
+
+ hbus->state = hv_pcibus_init;
+
+ ret = vmbus_open(hdev->channel, pci_ring_size, pci_ring_size, NULL, 0,
+ hv_pci_onchannelcallback, hbus);
+ if (ret)
+ return ret;
+
+ /* Only use the version that was in use before hibernation. */
+ version[0] = pci_protocol_version;
+ ret = hv_pci_protocol_negotiation(hdev, version, 1);
+ if (ret)
+ goto out;
+
+ ret = hv_pci_query_relations(hdev);
+ if (ret)
+ goto out;
+
+ ret = hv_pci_enter_d0(hdev);
+ if (ret)
+ goto out;
+
+ ret = hv_send_resources_allocated(hdev);
+ if (ret)
+ goto out;
+
+ prepopulate_bars(hbus);
+
+ hbus->state = hv_pcibus_installed;
+ return 0;
+out:
+ vmbus_close(hdev->channel);
+ return ret;
+}
+
static const struct hv_vmbus_device_id hv_pci_id_table[] = {
/* PCI Pass-through Class ID */
/* 44C4F61D-4444-4400-9D52-802E27EDE19F */
@@ -2751,6 +2825,8 @@ static int hv_pci_remove(struct hv_device *hdev)
.id_table = hv_pci_id_table,
.probe = hv_pci_probe,
.remove = hv_pci_remove,
+ .suspend = hv_pci_suspend,
+ .resume = hv_pci_resume,
};

static void __exit exit_hv_pci_drv(void)
--
1.8.3.1
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