Merge branch 'pci/portdrv'

- Allow portdrv to claim subtractive decode Ports so PCIe services will
    work for them (Honghui Zhang)

  - Report PCIe links that become degraded at run-time (Alexandru Gagniuc)

* pci/portdrv:
  PCI/LINK: Report degraded links via link bandwidth notification
  PCI/portdrv: Support PCIe services on subtractive decode bridges
  PCI/portdrv: Use conventional Device ID table formatting

drivers/pci/pcie/Makefile

@@ -3,6 +3,7 @@
 # Makefile for PCI Express features and port driver
 
 pcieportdrv-y			:= portdrv_core.o portdrv_pci.o err.o
+pcieportdrv-y			+= bw_notification.o
 
 obj-$(CONFIG_PCIEPORTBUS)	+= pcieportdrv.o
 

drivers/pci/pcie/bw_notification.c

@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * PCI Express Link Bandwidth Notification services driver
+ * Author: Alexandru Gagniuc <mr.nuke.me@gmail.com>
+ *
+ * Copyright (C) 2019, Dell Inc
+ *
+ * The PCIe Link Bandwidth Notification provides a way to notify the
+ * operating system when the link width or data rate changes.  This
+ * capability is required for all root ports and downstream ports
+ * supporting links wider than x1 and/or multiple link speeds.
+ *
+ * This service port driver hooks into the bandwidth notification interrupt
+ * and warns when links become degraded in operation.
+ */
+
+#include "../pci.h"
+#include "portdrv.h"
+
+static bool pcie_link_bandwidth_notification_supported(struct pci_dev *dev)
+{
+	int ret;
+	u32 lnk_cap;
+
+	ret = pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &lnk_cap);
+	return (ret == PCIBIOS_SUCCESSFUL) && (lnk_cap & PCI_EXP_LNKCAP_LBNC);
+}
+
+static void pcie_enable_link_bandwidth_notification(struct pci_dev *dev)
+{
+	u16 lnk_ctl;
+
+	pcie_capability_read_word(dev, PCI_EXP_LNKCTL, &lnk_ctl);
+	lnk_ctl |= PCI_EXP_LNKCTL_LBMIE;
+	pcie_capability_write_word(dev, PCI_EXP_LNKCTL, lnk_ctl);
+}
+
+static void pcie_disable_link_bandwidth_notification(struct pci_dev *dev)
+{
+	u16 lnk_ctl;
+
+	pcie_capability_read_word(dev, PCI_EXP_LNKCTL, &lnk_ctl);
+	lnk_ctl &= ~PCI_EXP_LNKCTL_LBMIE;
+	pcie_capability_write_word(dev, PCI_EXP_LNKCTL, lnk_ctl);
+}
+
+static irqreturn_t pcie_bw_notification_handler(int irq, void *context)
+{
+	struct pcie_device *srv = context;
+	struct pci_dev *port = srv->port;
+	struct pci_dev *dev;
+	u16 link_status, events;
+	int ret;
+
+	ret = pcie_capability_read_word(port, PCI_EXP_LNKSTA, &link_status);
+	events = link_status & PCI_EXP_LNKSTA_LBMS;
+
+	if (ret != PCIBIOS_SUCCESSFUL || !events)
+		return IRQ_NONE;
+
+	/*
+	 * Print status from downstream devices, not this root port or
+	 * downstream switch port.
+	 */
+	down_read(&pci_bus_sem);
+	list_for_each_entry(dev, &port->subordinate->devices, bus_list)
+		__pcie_print_link_status(dev, false);
+	up_read(&pci_bus_sem);
+
+	pcie_update_link_speed(port->subordinate, link_status);
+	pcie_capability_write_word(port, PCI_EXP_LNKSTA, events);
+	return IRQ_HANDLED;
+}
+
+static int pcie_bandwidth_notification_probe(struct pcie_device *srv)
+{
+	int ret;
+
+	/* Single-width or single-speed ports do not have to support this. */
+	if (!pcie_link_bandwidth_notification_supported(srv->port))
+		return -ENODEV;
+
+	ret = request_threaded_irq(srv->irq, NULL, pcie_bw_notification_handler,
+				   IRQF_SHARED, "PCIe BW notif", srv);
+	if (ret)
+		return ret;
+
+	pcie_enable_link_bandwidth_notification(srv->port);
+
+	return 0;
+}
+
+static void pcie_bandwidth_notification_remove(struct pcie_device *srv)
+{
+	pcie_disable_link_bandwidth_notification(srv->port);
+	free_irq(srv->irq, srv);
+}
+
+static struct pcie_port_service_driver pcie_bandwidth_notification_driver = {
+	.name		= "pcie_bw_notification",
+	.port_type	= PCIE_ANY_PORT,
+	.service	= PCIE_PORT_SERVICE_BWNOTIF,
+	.probe		= pcie_bandwidth_notification_probe,
+	.remove		= pcie_bandwidth_notification_remove,
+};
+
+int __init pcie_bandwidth_notification_init(void)
+{
+	return pcie_port_service_register(&pcie_bandwidth_notification_driver);
+}

drivers/pci/pcie/portdrv.h

@@ -20,8 +20,10 @@
 #define PCIE_PORT_SERVICE_HP		(1 << PCIE_PORT_SERVICE_HP_SHIFT)
 #define PCIE_PORT_SERVICE_DPC_SHIFT	3	/* Downstream Port Containment */
 #define PCIE_PORT_SERVICE_DPC		(1 << PCIE_PORT_SERVICE_DPC_SHIFT)
+#define PCIE_PORT_SERVICE_BWNOTIF_SHIFT	4	/* Bandwidth notification */
+#define PCIE_PORT_SERVICE_BWNOTIF	(1 << PCIE_PORT_SERVICE_BWNOTIF_SHIFT)
 
-#define PCIE_PORT_DEVICE_MAXSERVICES   4
+#define PCIE_PORT_DEVICE_MAXSERVICES   5
 
 #ifdef CONFIG_PCIEAER
 int pcie_aer_init(void);
@@ -47,6 +49,8 @@ int pcie_dpc_init(void);
 static inline int pcie_dpc_init(void) { return 0; }
 #endif
 
+int pcie_bandwidth_notification_init(void);
+
 /* Port Type */
 #define PCIE_ANY_PORT			(~0)
 

drivers/pci/pcie/portdrv_core.c

@@ -99,7 +99,7 @@ static int pcie_message_numbers(struct pci_dev *dev, int mask,
  */
 static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
 {
-	int nr_entries, nvec;
+	int nr_entries, nvec, pcie_irq;
 	u32 pme = 0, aer = 0, dpc = 0;
 
 	/* Allocate the maximum possible number of MSI/MSI-X vectors */
@@ -135,10 +135,13 @@ static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
 			return nr_entries;
 	}
 
-	/* PME and hotplug share an MSI/MSI-X vector */
-	if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP)) {
-		irqs[PCIE_PORT_SERVICE_PME_SHIFT] = pci_irq_vector(dev, pme);
-		irqs[PCIE_PORT_SERVICE_HP_SHIFT] = pci_irq_vector(dev, pme);
+	/* PME, hotplug and bandwidth notification share an MSI/MSI-X vector */
+	if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP |
+		    PCIE_PORT_SERVICE_BWNOTIF)) {
+		pcie_irq = pci_irq_vector(dev, pme);
+		irqs[PCIE_PORT_SERVICE_PME_SHIFT] = pcie_irq;
+		irqs[PCIE_PORT_SERVICE_HP_SHIFT] = pcie_irq;
+		irqs[PCIE_PORT_SERVICE_BWNOTIF_SHIFT] = pcie_irq;
 	}
 
 	if (mask & PCIE_PORT_SERVICE_AER)
@@ -250,6 +253,10 @@ static int get_port_device_capability(struct pci_dev *dev)
 	    pci_aer_available() && services & PCIE_PORT_SERVICE_AER)
 		services |= PCIE_PORT_SERVICE_DPC;
 
+	if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM ||
+	    pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
+		services |= PCIE_PORT_SERVICE_BWNOTIF;
+
 	return services;
 }
 

drivers/pci/pcie/portdrv_pci.c

@@ -182,10 +182,12 @@ static void pcie_portdrv_err_resume(struct pci_dev *dev)
 /*
  * LINUX Device Driver Model
  */
-static const struct pci_device_id port_pci_ids[] = { {
+static const struct pci_device_id port_pci_ids[] = {
 	/* handle any PCI-Express port */
-	PCI_DEVICE_CLASS(((PCI_CLASS_BRIDGE_PCI << 8) | 0x00), ~0),
-	}, { /* end: all zeroes */ }
+	{ PCI_DEVICE_CLASS(((PCI_CLASS_BRIDGE_PCI << 8) | 0x00), ~0) },
+	/* subtractive decode PCI-to-PCI bridge, class type is 060401h */
+	{ PCI_DEVICE_CLASS(((PCI_CLASS_BRIDGE_PCI << 8) | 0x01), ~0) },
+	{ },
 };
 
 static const struct pci_error_handlers pcie_portdrv_err_handler = {
@@ -238,6 +240,7 @@ static void __init pcie_init_services(void)
 	pcie_pme_init();
 	pcie_dpc_init();
 	pcie_hp_init();
+	pcie_bandwidth_notification_init();
 }
 
 static int __init pcie_portdrv_init(void)