+static int swsci(struct drm_device *dev, u32 function, u32 parm, u32 *parm_out)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ struct opregion_swsci __iomem *swsci = dev_priv->opregion.swsci;
+ u32 main_function, sub_function, scic;
+ u16 pci_swsci;
+ u32 dslp;
+
+ if (!swsci)
+ return -ENODEV;
+
+ main_function = (function & SWSCI_SCIC_MAIN_FUNCTION_MASK) >>
+ SWSCI_SCIC_MAIN_FUNCTION_SHIFT;
+ sub_function = (function & SWSCI_SCIC_SUB_FUNCTION_MASK) >>
+ SWSCI_SCIC_SUB_FUNCTION_SHIFT;
+
+ /* Check if we can call the function. See swsci_setup for details. */
+ if (main_function == SWSCI_SBCB) {
+ if ((dev_priv->opregion.swsci_sbcb_sub_functions &
+ (1 << sub_function)) == 0)
+ return -EINVAL;
+ } else if (main_function == SWSCI_GBDA) {
+ if ((dev_priv->opregion.swsci_gbda_sub_functions &
+ (1 << sub_function)) == 0)
+ return -EINVAL;
+ }
+
+ /* Driver sleep timeout in ms. */
+ dslp = ioread32(&swsci->dslp);
+ if (!dslp) {
+ dslp = 2;
+ } else if (dslp > 500) {
+ /* Hey bios, trust must be earned. */
+ WARN_ONCE(1, "excessive driver sleep timeout (DSPL) %u\n", dslp);
+ dslp = 500;
+ }
+
+ /* The spec tells us to do this, but we are the only user... */
+ scic = ioread32(&swsci->scic);
+ if (scic & SWSCI_SCIC_INDICATOR) {
+ DRM_DEBUG_DRIVER("SWSCI request already in progress\n");
+ return -EBUSY;
+ }
+
+ scic = function | SWSCI_SCIC_INDICATOR;
+
+ iowrite32(parm, &swsci->parm);
+ iowrite32(scic, &swsci->scic);
+
+ /* Ensure SCI event is selected and event trigger is cleared. */
+ pci_read_config_word(dev->pdev, PCI_SWSCI, &pci_swsci);
+ if (!(pci_swsci & PCI_SWSCI_SCISEL) || (pci_swsci & PCI_SWSCI_GSSCIE)) {
+ pci_swsci |= PCI_SWSCI_SCISEL;
+ pci_swsci &= ~PCI_SWSCI_GSSCIE;
+ pci_write_config_word(dev->pdev, PCI_SWSCI, pci_swsci);
+ }
+
+ /* Use event trigger to tell bios to check the mail. */
+ pci_swsci |= PCI_SWSCI_GSSCIE;
+ pci_write_config_word(dev->pdev, PCI_SWSCI, pci_swsci);
+
+ /* Poll for the result. */
+#define C (((scic = ioread32(&swsci->scic)) & SWSCI_SCIC_INDICATOR) == 0)
+ if (wait_for(C, dslp)) {
+ DRM_DEBUG_DRIVER("SWSCI request timed out\n");
+ return -ETIMEDOUT;
+ }
+
+ scic = (scic & SWSCI_SCIC_EXIT_STATUS_MASK) >>
+ SWSCI_SCIC_EXIT_STATUS_SHIFT;
+
+ /* Note: scic == 0 is an error! */
+ if (scic != SWSCI_SCIC_EXIT_STATUS_SUCCESS) {
+ DRM_DEBUG_DRIVER("SWSCI request error %u\n", scic);
+ return -EIO;
+ }
+
+ if (parm_out)
+ *parm_out = ioread32(&swsci->parm);
+
+ return 0;
+
+#undef C
+}
+