[PATCH] PCI: restore BAR values after D3hot->D0 for devices that need it

[linux-2.6-omap-h63xx.git] / drivers / pci / pci.c

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 1b34fc56067ed8ae0ba9b32f46679e13068bb86c..65ea7d25f6911d7396e19afbf4bb2738906376f7 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -221,6 +221,37 @@ pci_find_parent_resource(const struct pci_dev *dev, struct resource *res)
        return best;
 }
 
+/**
+ * pci_restore_bars - restore a devices BAR values (e.g. after wake-up)
+ * @dev: PCI device to have its BARs restored
+ *
+ * Restore the BAR values for a given device, so as to make it
+ * accessible by its driver.
+ */
+void
+pci_restore_bars(struct pci_dev *dev)
+{
+       int i, numres;
+
+       switch (dev->hdr_type) {
+       case PCI_HEADER_TYPE_NORMAL:
+               numres = 6;
+               break;
+       case PCI_HEADER_TYPE_BRIDGE:
+               numres = 2;
+               break;
+       case PCI_HEADER_TYPE_CARDBUS:
+               numres = 1;
+               break;
+       default:
+               /* Should never get here, but just in case... */
+               return;
+       }
+
+       for (i = 0; i < numres; i ++)
+               pci_update_resource(dev, &dev->resource[i], i);
+}
+
 /**
  * pci_set_power_state - Set the power state of a PCI device
  * @dev: PCI device to be suspended
@@ -239,7 +270,7 @@ int (*platform_pci_set_power_state)(struct pci_dev *dev, pci_power_t t);
 int
 pci_set_power_state(struct pci_dev *dev, pci_power_t state)
 {
-       int pm;
+       int pm, need_restore = 0;
        u16 pmcsr, pmc;
 
        /* bound the state we're entering */
@@ -278,14 +309,17 @@ pci_set_power_state(struct pci_dev *dev, pci_power_t state)
                        return -EIO;
        }
 
+       pci_read_config_word(dev, pm + PCI_PM_CTRL, &pmcsr);
+
        /* If we're in D3, force entire word to 0.
         * This doesn't affect PME_Status, disables PME_En, and
         * sets PowerState to 0.
         */
-       if (dev->current_state >= PCI_D3hot)
+       if (dev->current_state >= PCI_D3hot) {
+               if (!(pmcsr & PCI_PM_CTRL_NO_SOFT_RESET))
+                       need_restore = 1;
                pmcsr = 0;
-       else {
-               pci_read_config_word(dev, pm + PCI_PM_CTRL, &pmcsr);
+       } else {
                pmcsr &= ~PCI_PM_CTRL_STATE_MASK;
                pmcsr |= state;
        }
@@ -308,6 +342,22 @@ pci_set_power_state(struct pci_dev *dev, pci_power_t state)
                platform_pci_set_power_state(dev, state);
 
        dev->current_state = state;
+
+       /* According to section 5.4.1 of the "PCI BUS POWER MANAGEMENT
+        * INTERFACE SPECIFICATION, REV. 1.2", a device transitioning
+        * from D3hot to D0 _may_ perform an internal reset, thereby
+        * going to "D0 Uninitialized" rather than "D0 Initialized".
+        * For example, at least some versions of the 3c905B and the
+        * 3c556B exhibit this behaviour.
+        *
+        * At least some laptop BIOSen (e.g. the Thinkpad T21) leave
+        * devices in a D3hot state at boot.  Consequently, we need to
+        * restore at least the BARs so that the device will be
+        * accessible to its driver.
+        */
+       if (need_restore)
+               pci_restore_bars(dev);
+
        return 0;
 }
 
@@ -805,6 +855,7 @@ struct pci_dev *isa_bridge;
 EXPORT_SYMBOL(isa_bridge);
 #endif
 
+EXPORT_SYMBOL_GPL(pci_restore_bars);
 EXPORT_SYMBOL(pci_enable_device_bars);
 EXPORT_SYMBOL(pci_enable_device);
 EXPORT_SYMBOL(pci_disable_device);