PCI: hv: Generify PCI probing

In order to support ARM64 Hyper-V PCI, we need to set up the bridge at
probing time because ARM64 is a PCI_DOMAIN_GENERIC=y arch and we don't
have pci_config_window (ARM64 sysdata) for a PCI root bus on Hyper-V, so
it's impossible to retrieve the information (e.g. PCI domains, MSI
domains) from bus sysdata on ARM64 after creation.

Originally in create_root_hv_pci_bus(), pci_create_root_bus() is used to
create the root bus and the corresponding bridge based on x86 sysdata.
Now we create a bridge first and then call pci_scan_root_bus_bridge(),
which allows us to do the necessary set-ups for the bridge.

Link: https://lore.kernel.org/r/20210726180657.142727-6-boqun.feng@gmail.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index a53bd87..8d42da5 100644 (file)
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -449,6 +449,7 @@ enum hv_pcibus_state {
 
 struct hv_pcibus_device {
        struct pci_sysdata sysdata;
+       struct pci_host_bridge *bridge;
        /* Protocol version negotiated with the host */
        enum pci_protocol_version_t protocol_version;
        enum hv_pcibus_state state;
@@ -464,8 +465,6 @@ struct hv_pcibus_device {
        spinlock_t device_list_lock;    /* Protect lists below */
        void __iomem *cfg_addr;
 
-       struct list_head resources_for_children;
-
        struct list_head children;
        struct list_head dr_list;
 
@@ -1797,7 +1796,7 @@ static void hv_pci_assign_slots(struct hv_pcibus_device *hbus)
 
                slot_nr = PCI_SLOT(wslot_to_devfn(hpdev->desc.win_slot.slot));
                snprintf(name, SLOT_NAME_SIZE, "%u", hpdev->desc.ser);
-               hpdev->pci_slot = pci_create_slot(hbus->pci_bus, slot_nr,
+               hpdev->pci_slot = pci_create_slot(hbus->bridge->bus, slot_nr,
                                          name, NULL);
                if (IS_ERR(hpdev->pci_slot)) {
                        pr_warn("pci_create slot %s failed\n", name);
@@ -1827,7 +1826,7 @@ static void hv_pci_remove_slots(struct hv_pcibus_device *hbus)
 static void hv_pci_assign_numa_node(struct hv_pcibus_device *hbus)
 {
        struct pci_dev *dev;
-       struct pci_bus *bus = hbus->pci_bus;
+       struct pci_bus *bus = hbus->bridge->bus;
        struct hv_pci_dev *hv_dev;
 
        list_for_each_entry(dev, &bus->devices, bus_list) {
@@ -1850,21 +1849,22 @@ static void hv_pci_assign_numa_node(struct hv_pcibus_device *hbus)
  */
 static int create_root_hv_pci_bus(struct hv_pcibus_device *hbus)
 {
-       /* Register the device */
-       hbus->pci_bus = pci_create_root_bus(&hbus->hdev->device,
-                                           0, /* bus number is always zero */
-                                           &hv_pcifront_ops,
-                                           &hbus->sysdata,
-                                           &hbus->resources_for_children);
-       if (!hbus->pci_bus)
-               return -ENODEV;
+       int error;
+       struct pci_host_bridge *bridge = hbus->bridge;
+
+       bridge->dev.parent = &hbus->hdev->device;
+       bridge->sysdata = &hbus->sysdata;
+       bridge->ops = &hv_pcifront_ops;
+
+       error = pci_scan_root_bus_bridge(bridge);
+       if (error)
+               return error;
 
        pci_lock_rescan_remove();
-       pci_scan_child_bus(hbus->pci_bus);
        hv_pci_assign_numa_node(hbus);
-       pci_bus_assign_resources(hbus->pci_bus);
+       pci_bus_assign_resources(bridge->bus);
        hv_pci_assign_slots(hbus);
-       pci_bus_add_devices(hbus->pci_bus);
+       pci_bus_add_devices(bridge->bus);
        pci_unlock_rescan_remove();
        hbus->state = hv_pcibus_installed;
        return 0;
@@ -2127,7 +2127,7 @@ static void pci_devices_present_work(struct work_struct *work)
                 * because there may have been changes.
                 */
                pci_lock_rescan_remove();
-               pci_scan_child_bus(hbus->pci_bus);
+               pci_scan_child_bus(hbus->bridge->bus);
                hv_pci_assign_numa_node(hbus);
                hv_pci_assign_slots(hbus);
                pci_unlock_rescan_remove();
@@ -2295,8 +2295,8 @@ static void hv_eject_device_work(struct work_struct *work)
        /*
         * Ejection can come before or after the PCI bus has been set up, so
         * attempt to find it and tear down the bus state, if it exists.  This
-        * must be done without constructs like pci_domain_nr(hbus->pci_bus)
-        * because hbus->pci_bus may not exist yet.
+        * must be done without constructs like pci_domain_nr(hbus->bridge->bus)
+        * because hbus->bridge->bus may not exist yet.
         */
        wslot = wslot_to_devfn(hpdev->desc.win_slot.slot);
        pdev = pci_get_domain_bus_and_slot(hbus->sysdata.domain, 0, wslot);
@@ -2662,8 +2662,7 @@ static int hv_pci_allocate_bridge_windows(struct hv_pcibus_device *hbus)
                /* Modify this resource to become a bridge window. */
                hbus->low_mmio_res->flags |= IORESOURCE_WINDOW;
                hbus->low_mmio_res->flags &= ~IORESOURCE_BUSY;
-               pci_add_resource(&hbus->resources_for_children,
-                                hbus->low_mmio_res);
+               pci_add_resource(&hbus->bridge->windows, hbus->low_mmio_res);
        }
 
        if (hbus->high_mmio_space) {
@@ -2682,8 +2681,7 @@ static int hv_pci_allocate_bridge_windows(struct hv_pcibus_device *hbus)
                /* Modify this resource to become a bridge window. */
                hbus->high_mmio_res->flags |= IORESOURCE_WINDOW;
                hbus->high_mmio_res->flags &= ~IORESOURCE_BUSY;
-               pci_add_resource(&hbus->resources_for_children,
-                                hbus->high_mmio_res);
+               pci_add_resource(&hbus->bridge->windows, hbus->high_mmio_res);
        }
 
        return 0;
@@ -3002,6 +3000,7 @@ static void hv_put_dom_num(u16 dom)
 static int hv_pci_probe(struct hv_device *hdev,
                        const struct hv_vmbus_device_id *dev_id)
 {
+       struct pci_host_bridge *bridge;
        struct hv_pcibus_device *hbus;
        u16 dom_req, dom;
        char *name;
@@ -3014,6 +3013,10 @@ static int hv_pci_probe(struct hv_device *hdev,
         */
        BUILD_BUG_ON(sizeof(*hbus) > HV_HYP_PAGE_SIZE);
 
+       bridge = devm_pci_alloc_host_bridge(&hdev->device, 0);
+       if (!bridge)
+               return -ENOMEM;
+
        /*
         * With the recent 59bb47985c1d ("mm, sl[aou]b: guarantee natural
         * alignment for kmalloc(power-of-two)"), kzalloc() is able to allocate
@@ -3035,6 +3038,8 @@ static int hv_pci_probe(struct hv_device *hdev,
        hbus = kzalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
        if (!hbus)
                return -ENOMEM;
+
+       hbus->bridge = bridge;
        hbus->state = hv_pcibus_init;
        hbus->wslot_res_allocated = -1;
 
@@ -3071,7 +3076,6 @@ static int hv_pci_probe(struct hv_device *hdev,
        hbus->hdev = hdev;
        INIT_LIST_HEAD(&hbus->children);
        INIT_LIST_HEAD(&hbus->dr_list);
-       INIT_LIST_HEAD(&hbus->resources_for_children);
        spin_lock_init(&hbus->config_lock);
        spin_lock_init(&hbus->device_list_lock);
        spin_lock_init(&hbus->retarget_msi_interrupt_lock);
@@ -3295,9 +3299,9 @@ static int hv_pci_remove(struct hv_device *hdev)
 
                /* Remove the bus from PCI's point of view. */
                pci_lock_rescan_remove();
-               pci_stop_root_bus(hbus->pci_bus);
+               pci_stop_root_bus(hbus->bridge->bus);
                hv_pci_remove_slots(hbus);
-               pci_remove_root_bus(hbus->pci_bus);
+               pci_remove_root_bus(hbus->bridge->bus);
                pci_unlock_rescan_remove();
        }
 
@@ -3307,7 +3311,6 @@ static int hv_pci_remove(struct hv_device *hdev)
 
        iounmap(hbus->cfg_addr);
        hv_free_config_window(hbus);
-       pci_free_resource_list(&hbus->resources_for_children);
        hv_pci_free_bridge_windows(hbus);
        irq_domain_remove(hbus->irq_domain);
        irq_domain_free_fwnode(hbus->sysdata.fwnode);
@@ -3390,7 +3393,7 @@ static int hv_pci_restore_msi_msg(struct pci_dev *pdev, void *arg)
  */
 static void hv_pci_restore_msi_state(struct hv_pcibus_device *hbus)
 {
-       pci_walk_bus(hbus->pci_bus, hv_pci_restore_msi_msg, NULL);
+       pci_walk_bus(hbus->bridge->bus, hv_pci_restore_msi_msg, NULL);
 }
 
 static int hv_pci_resume(struct hv_device *hdev)