[RFC v2 3/7] PCI: hv: Generify PCI probing

Boqun Feng
2021-05-03T14:49:57Z

From: Arnd Bergmann <arnd@arndb.de>

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 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, irq
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.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
drivers/pci/controller/pci-hyperv.c | 61 +++++++++++++++--------------
1 file changed, 31 insertions(+), 30 deletions(-)

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index 27a17a1e4a7c..27b922b4bb7b 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -450,6 +450,7 @@ 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;
@@ -462,13 +463,10 @@ struct hv_pcibus_device {
struct resource *high_mmio_res;
struct completion *survey_event;
struct completion remove_event;
- struct pci_bus *pci_bus;
spinlock_t config_lock; /* Avoid two threads writing index page */
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;

@@ -1804,7 +1802,7 @@ 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);
@@ -1834,7 +1832,7 @@ 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) {
@@ -1857,24 +1855,24 @@ 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;
+ bridge->msi = &hbus->msi_chip;
+ bridge->msi->dev = &hbus->hdev->device;

- hbus->pci_bus->msi = &hbus->msi_chip;
- hbus->pci_bus->msi->dev = &hbus->hdev->device;
+ 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;
@@ -2139,7 +2137,7 @@ 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();
@@ -2310,8 +2308,8 @@ 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);
@@ -2680,8 +2678,7 @@ 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) {
@@ -2700,8 +2697,7 @@ 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;
@@ -3031,6 +3027,7 @@ 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;
@@ -3043,6 +3040,10 @@ 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
@@ -3064,6 +3065,8 @@ 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;

@@ -3101,7 +3104,6 @@ static int hv_pci_probe(struct hv_device *hdev,
refcount_set(&hbus->remove_lock, 1);
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);
@@ -3307,9 +3309,9 @@ static int hv_pci_remove(struct hv_device *hdev)
if (hbus->state == hv_pcibus_installed) {
/* 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();
hbus->state = hv_pcibus_removed;
}
@@ -3320,7 +3322,6 @@ 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);
@@ -3406,7 +3407,7 @@ 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)