Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 1a522c1..88b9967 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -201,17 +201,29 @@
 	pcie_do_write_cmd(ctrl, cmd, mask, false);
 }
 
-bool pciehp_check_link_active(struct controller *ctrl)
+/**
+ * pciehp_check_link_active() - Is the link active
+ * @ctrl: PCIe hotplug controller
+ *
+ * Check whether the downstream link is currently active. Note it is
+ * possible that the card is removed immediately after this so the
+ * caller may need to take it into account.
+ *
+ * If the hotplug controller itself is not available anymore returns
+ * %-ENODEV.
+ */
+int pciehp_check_link_active(struct controller *ctrl)
 {
 	struct pci_dev *pdev = ctrl_dev(ctrl);
 	u16 lnk_status;
-	bool ret;
+	int ret;
 
-	pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
+	ret = pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
+	if (ret == PCIBIOS_DEVICE_NOT_FOUND || lnk_status == (u16)~0)
+		return -ENODEV;
+
 	ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);
-
-	if (ret)
-		ctrl_dbg(ctrl, "%s: lnk_status = %x\n", __func__, lnk_status);
+	ctrl_dbg(ctrl, "%s: lnk_status = %x\n", __func__, lnk_status);
 
 	return ret;
 }
@@ -373,13 +385,29 @@
 	*status = !!(slot_status & PCI_EXP_SLTSTA_MRLSS);
 }
 
-bool pciehp_card_present(struct controller *ctrl)
+/**
+ * pciehp_card_present() - Is the card present
+ * @ctrl: PCIe hotplug controller
+ *
+ * Function checks whether the card is currently present in the slot and
+ * in that case returns true. Note it is possible that the card is
+ * removed immediately after the check so the caller may need to take
+ * this into account.
+ *
+ * It the hotplug controller itself is not available anymore returns
+ * %-ENODEV.
+ */
+int pciehp_card_present(struct controller *ctrl)
 {
 	struct pci_dev *pdev = ctrl_dev(ctrl);
 	u16 slot_status;
+	int ret;
 
-	pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
-	return slot_status & PCI_EXP_SLTSTA_PDS;
+	ret = pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
+	if (ret == PCIBIOS_DEVICE_NOT_FOUND || slot_status == (u16)~0)
+		return -ENODEV;
+
+	return !!(slot_status & PCI_EXP_SLTSTA_PDS);
 }
 
 /**
@@ -390,10 +418,19 @@
  * Presence Detect State bit, this helper also returns true if the Link Active
  * bit is set.  This is a concession to broken hotplug ports which hardwire
  * Presence Detect State to zero, such as Wilocity's [1ae9:0200].
+ *
+ * Returns: %1 if the slot is occupied and %0 if it is not. If the hotplug
+ *	    port is not present anymore returns %-ENODEV.
  */
-bool pciehp_card_present_or_link_active(struct controller *ctrl)
+int pciehp_card_present_or_link_active(struct controller *ctrl)
 {
-	return pciehp_card_present(ctrl) || pciehp_check_link_active(ctrl);
+	int ret;
+
+	ret = pciehp_card_present(ctrl);
+	if (ret)
+		return ret;
+
+	return pciehp_check_link_active(ctrl);
 }
 
 int pciehp_query_power_fault(struct controller *ctrl)
@@ -492,7 +529,7 @@
 	struct controller *ctrl = (struct controller *)dev_id;
 	struct pci_dev *pdev = ctrl_dev(ctrl);
 	struct device *parent = pdev->dev.parent;
-	u16 status, events;
+	u16 status, events = 0;
 
 	/*
 	 * Interrupts only occur in D3hot or shallower and only if enabled
@@ -517,6 +554,7 @@
 		}
 	}
 
+read_status:
 	pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &status);
 	if (status == (u16) ~0) {
 		ctrl_info(ctrl, "%s: no response from device\n", __func__);
@@ -529,24 +567,37 @@
 	 * Slot Status contains plain status bits as well as event
 	 * notification bits; right now we only want the event bits.
 	 */
-	events = status & (PCI_EXP_SLTSTA_ABP | PCI_EXP_SLTSTA_PFD |
-			   PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_CC |
-			   PCI_EXP_SLTSTA_DLLSC);
+	status &= PCI_EXP_SLTSTA_ABP | PCI_EXP_SLTSTA_PFD |
+		  PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_CC |
+		  PCI_EXP_SLTSTA_DLLSC;
 
 	/*
 	 * If we've already reported a power fault, don't report it again
 	 * until we've done something to handle it.
 	 */
 	if (ctrl->power_fault_detected)
-		events &= ~PCI_EXP_SLTSTA_PFD;
+		status &= ~PCI_EXP_SLTSTA_PFD;
 
+	events |= status;
 	if (!events) {
 		if (parent)
 			pm_runtime_put(parent);
 		return IRQ_NONE;
 	}
 
-	pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, events);
+	if (status) {
+		pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, events);
+
+		/*
+		 * In MSI mode, all event bits must be zero before the port
+		 * will send a new interrupt (PCIe Base Spec r5.0 sec 6.7.3.4).
+		 * So re-read the Slot Status register in case a bit was set
+		 * between read and write.
+		 */
+		if (pci_dev_msi_enabled(pdev) && !pciehp_poll_mode)
+			goto read_status;
+	}
+
 	ctrl_dbg(ctrl, "pending interrupts %#06x from Slot Status\n", events);
 	if (parent)
 		pm_runtime_put(parent);
@@ -583,23 +634,22 @@
 	irqreturn_t ret;
 	u32 events;
 
+	ctrl->ist_running = true;
 	pci_config_pm_runtime_get(pdev);
 
 	/* rerun pciehp_isr() if the port was inaccessible on interrupt */
 	if (atomic_fetch_and(~RERUN_ISR, &ctrl->pending_events) & RERUN_ISR) {
 		ret = pciehp_isr(irq, dev_id);
 		enable_irq(irq);
-		if (ret != IRQ_WAKE_THREAD) {
-			pci_config_pm_runtime_put(pdev);
-			return ret;
-		}
+		if (ret != IRQ_WAKE_THREAD)
+			goto out;
 	}
 
 	synchronize_hardirq(irq);
 	events = atomic_xchg(&ctrl->pending_events, 0);
 	if (!events) {
-		pci_config_pm_runtime_put(pdev);
-		return IRQ_NONE;
+		ret = IRQ_NONE;
+		goto out;
 	}
 
 	/* Check Attention Button Pressed */
@@ -628,9 +678,12 @@
 		pciehp_handle_presence_or_link_change(ctrl, events);
 	up_read(&ctrl->reset_lock);
 
+	ret = IRQ_HANDLED;
+out:
 	pci_config_pm_runtime_put(pdev);
+	ctrl->ist_running = false;
 	wake_up(&ctrl->requester);
-	return IRQ_HANDLED;
+	return ret;
 }
 
 static int pciehp_poll(void *data)