ACPI: Introduce acpi_get_pci_dev()

Convert an ACPI CA handle to a struct pci_dev.

Performing this lookup dynamically allows us to get rid of the
ACPI-PCI binding code, which:

	- eliminates struct acpi_device vs struct pci_dev lifetime issues
	- lays more groundwork for eliminating .start from acpi_device_ops
	  and thus simplifying ACPI drivers
	- whacks out a lot of code

This change lays the groundwork for eliminating much of pci_bind.c.

Although pci_root.c may not be the most logical place for this
change, putting it here saves us from having to export acpi_pci_find_root.

Signed-off-by: Alex Chiang <achiang@hp.com>
Acked-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 888cb9f5c5fbf563354af0f89a75da6af8f0202c..e5099919e574260ef64e8fe21566aaccffc53b5c 100644 (file)
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -329,6 +329,87 @@ static struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle)
        return NULL;
 }
 
+struct acpi_handle_node {
+       struct list_head node;
+       acpi_handle handle;
+};
+
+/**
+ * acpi_get_pci_dev - convert ACPI CA handle to struct pci_dev
+ * @handle: the handle in question
+ *
+ * Given an ACPI CA handle, the desired PCI device is located in the
+ * list of PCI devices.
+ *
+ * If the device is found, its reference count is increased and this
+ * function returns a pointer to its data structure.  The caller must
+ * decrement the reference count by calling pci_dev_put().
+ * If no device is found, %NULL is returned.
+ */
+struct pci_dev *acpi_get_pci_dev(acpi_handle handle)
+{
+       int dev, fn;
+       unsigned long long adr;
+       acpi_status status;
+       acpi_handle phandle;
+       struct pci_bus *pbus;
+       struct pci_dev *pdev = NULL;
+       struct acpi_handle_node *node, *tmp;
+       struct acpi_pci_root *root;
+       LIST_HEAD(device_list);
+
+       /*
+        * Walk up the ACPI CA namespace until we reach a PCI root bridge.
+        */
+       phandle = handle;
+       while (!acpi_is_root_bridge(phandle)) {
+               node = kzalloc(sizeof(struct acpi_handle_node), GFP_KERNEL);
+               if (!node)
+                       goto out;
+
+               INIT_LIST_HEAD(&node->node);
+               node->handle = phandle;
+               list_add(&node->node, &device_list);
+
+               status = acpi_get_parent(phandle, &phandle);
+               if (ACPI_FAILURE(status))
+                       goto out;
+       }
+
+       root = acpi_pci_find_root(phandle);
+       if (!root)
+               goto out;
+
+       pbus = root->bus;
+
+       /*
+        * Now, walk back down the PCI device tree until we return to our
+        * original handle. Assumes that everything between the PCI root
+        * bridge and the device we're looking for must be a P2P bridge.
+        */
+       list_for_each_entry(node, &device_list, node) {
+               acpi_handle hnd = node->handle;
+               status = acpi_evaluate_integer(hnd, "_ADR", NULL, &adr);
+               if (ACPI_FAILURE(status))
+                       goto out;
+               dev = (adr >> 16) & 0xffff;
+               fn  = adr & 0xffff;
+
+               pdev = pci_get_slot(pbus, PCI_DEVFN(dev, fn));
+               if (hnd == handle)
+                       break;
+
+               pbus = pdev->subordinate;
+               pci_dev_put(pdev);
+       }
+out:
+       list_for_each_entry_safe(node, tmp, &device_list, node)
+               kfree(node);
+
+       return pdev;
+}
+EXPORT_SYMBOL_GPL(acpi_get_pci_dev);
+
 /**
  * acpi_pci_osc_control_set - commit requested control to Firmware
  * @handle: acpi_handle for the target ACPI object

diff --git a/include/acpi/acpi_drivers.h b/include/acpi/acpi_drivers.h
index 7a2ce53146aa9585ddf63599cf6a151e5f522390..dbe3989952ee99b9de3cea1d143b6b713515e67e 100644 (file)
--- a/include/acpi/acpi_drivers.h
+++ b/include/acpi/acpi_drivers.h
@@ -98,6 +98,7 @@ void acpi_pci_irq_del_prt(int segment, int bus);
 
 struct pci_bus;
 
+struct pci_dev *acpi_get_pci_dev(acpi_handle);
 acpi_status acpi_get_pci_id(acpi_handle handle, struct acpi_pci_id *id);
 int acpi_pci_bind_root(struct acpi_device *device, struct acpi_pci_id *id,
                       struct pci_bus *bus);