@@ -38,3 +38,11 @@ config CXL
CAPI adapters are found in POWER8 based systems.
If unsure, say N.
+
+config CXL_BIMODAL
+ bool "Support for bi-modal CAPI cards"
+ depends on HOTPLUG_PCI_POWERNV = y && CXL || HOTPLUG_PCI_POWERNV = m && CXL = m
+ default y
+ help
+ Select this option to enable support for bi-modal CAPI cards, such as
+ the Mellanox CX-4.
@@ -55,6 +55,8 @@
pci_read_config_byte(dev, vsec + 0xa, dest)
#define CXL_WRITE_VSEC_MODE_CONTROL(dev, vsec, val) \
pci_write_config_byte(dev, vsec + 0xa, val)
+#define CXL_WRITE_VSEC_MODE_CONTROL_BUS(bus, devfn, vsec, val) \
+ pci_bus_write_config_byte(bus, devfn, vsec + 0xa, val)
#define CXL_VSEC_PROTOCOL_MASK 0xe0
#define CXL_VSEC_PROTOCOL_1024TB 0x80
#define CXL_VSEC_PROTOCOL_512TB 0x40
@@ -614,36 +616,234 @@ static int setup_cxl_bars(struct pci_dev *dev)
return 0;
}
-/* pciex node: ibm,opal-m64-window = <0x3d058 0x0 0x3d058 0x0 0x8 0x0>; */
-static int switch_card_to_cxl(struct pci_dev *dev)
-{
+#ifdef CONFIG_CXL_BIMODAL
+
+struct cxl_switch_work {
+ struct pci_dev *dev;
+ struct work_struct work;
int vsec;
+ int mode;
+};
+
+static void switch_card_to_cxl(struct work_struct *work)
+{
+ struct cxl_switch_work *switch_work =
+ container_of(work, struct cxl_switch_work, work);
+ struct pci_dev *dev = switch_work->dev;
+ struct pci_bus *bus = dev->bus;
+ struct pci_controller *hose = pci_bus_to_host(bus);
+ struct pci_dev *bridge;
+ struct pnv_php_slot *php_slot;
+ unsigned int devfn;
u8 val;
int rc;
- dev_info(&dev->dev, "switch card to CXL\n");
+ dev_info(&bus->dev, "cxl: Preparing for mode switch...\n");
+ bridge = list_first_entry_or_null(&hose->bus->devices, struct pci_dev,
+ bus_list);
+ if (!bridge) {
+ dev_WARN(&bus->dev, "cxl: Couldn't find root port!\n");
+ goto err_dev_put;
+ }
- if (!(vsec = find_cxl_vsec(dev))) {
- dev_err(&dev->dev, "ABORTING: CXL VSEC not found!\n");
+ php_slot = pnv_php_find_slot(pci_device_to_OF_node(bridge));
+ if (!php_slot) {
+ dev_err(&bus->dev, "cxl: Failed to find slot hotplug "
+ "information. You may need to upgrade "
+ "skiboot. Aborting.\n");
+ goto err_dev_put;
+ }
+
+ rc = CXL_READ_VSEC_MODE_CONTROL(dev, switch_work->vsec, &val);
+ if (rc) {
+ dev_err(&bus->dev, "cxl: Failed to read CAPI mode control: %i\n", rc);
+ goto err_dev_put;
+ }
+ devfn = dev->devfn;
+
+ /* Release the reference obtained in cxl_check_and_switch_mode() */
+ pci_dev_put(dev);
+
+ dev_dbg(&bus->dev, "cxl: Removing PCI devices from kernel\n");
+ pci_lock_rescan_remove();
+ pci_hp_remove_devices(bridge->subordinate);
+ pci_unlock_rescan_remove();
+
+ /* Switch the CXL protocol on the card */
+ if (switch_work->mode == CXL_BIMODE_CXL) {
+ dev_info(&bus->dev, "cxl: Switching card to CXL mode\n");
+ val &= ~CXL_VSEC_PROTOCOL_MASK;
+ val |= CXL_VSEC_PROTOCOL_256TB | CXL_VSEC_PROTOCOL_ENABLE;
+ rc = pnv_cxl_enable_phb_kernel_api(hose, true);
+ if (rc) {
+ dev_err(&bus->dev, "cxl: Failed to enable kernel API"
+ " on real PHB, aborting\n");
+ goto err_free_work;
+ }
+ } else {
+ dev_WARN(&bus->dev, "cxl: Switching card to PCI mode not supported!\n");
+ goto err_free_work;
+ }
+
+ rc = CXL_WRITE_VSEC_MODE_CONTROL_BUS(bus, devfn, switch_work->vsec, val);
+ if (rc) {
+ dev_err(&bus->dev, "cxl: Failed to configure CXL protocol: %i\n", rc);
+ goto err_free_work;
+ }
+
+ /*
+ * The CAIA spec (v1.1, Section 10.6 Bi-modal Device Support) states
+ * we must wait 100ms after this mode switch before touching PCIe config
+ * space.
+ */
+ msleep(100);
+
+ /*
+ * Hot reset to cause the card to come back in cxl mode. A
+ * OPAL_RESET_PCI_LINK would be sufficient, but currently lacks support
+ * in skiboot, so we use a hot reset instead.
+ *
+ * We call pci_set_pcie_reset_state() on the bridge, as a CAPI card is
+ * guaranteed to sit directly under the root port, and setting the reset
+ * state on a device directly under the root port is equivalent to doing
+ * it on the root port iself.
+ */
+ dev_info(&bus->dev, "cxl: Configuration write complete, resetting card\n");
+ pci_set_pcie_reset_state(bridge, pcie_hot_reset);
+ pci_set_pcie_reset_state(bridge, pcie_deassert_reset);
+
+ dev_dbg(&bus->dev, "cxl: Offlining slot\n");
+ rc = pnv_php_set_slot_power_state(&php_slot->slot, OPAL_PCI_SLOT_OFFLINE);
+ if (rc) {
+ dev_err(&bus->dev, "cxl: OPAL offlining call failed: %i\n", rc);
+ goto err_free_work;
+ }
+
+ dev_dbg(&bus->dev, "cxl: Onlining and probing slot\n");
+ rc = pnv_php_set_slot_power_state(&php_slot->slot, OPAL_PCI_SLOT_ONLINE);
+ if (rc) {
+ dev_err(&bus->dev, "cxl: OPAL onlining call failed: %i\n", rc);
+ goto err_free_work;
+ }
+
+ pci_lock_rescan_remove();
+ pci_hp_add_devices(bridge->subordinate);
+ pci_unlock_rescan_remove();
+
+ dev_info(&bus->dev, "cxl: CAPI mode switch completed\n");
+ kfree(switch_work);
+ return;
+
+err_dev_put:
+ /* Release the reference obtained in cxl_check_and_switch_mode() */
+ pci_dev_put(dev);
+err_free_work:
+ kfree(switch_work);
+}
+
+int cxl_check_and_switch_mode(struct pci_dev *dev, int mode, int vsec)
+{
+ struct cxl_switch_work *work;
+ u8 val;
+ int rc;
+
+ if (!cpu_has_feature(CPU_FTR_HVMODE))
return -ENODEV;
+
+ if (!vsec) {
+ vsec = find_cxl_vsec(dev);
+ if (!vsec) {
+ dev_info(&dev->dev, "CXL VSEC not found\n");
+ return -ENODEV;
+ }
}
- if ((rc = CXL_READ_VSEC_MODE_CONTROL(dev, vsec, &val))) {
- dev_err(&dev->dev, "failed to read current mode control: %i", rc);
+ rc = CXL_READ_VSEC_MODE_CONTROL(dev, vsec, &val);
+ if (rc) {
+ dev_err(&dev->dev, "Failed to read current mode control: %i", rc);
return rc;
}
- val &= ~CXL_VSEC_PROTOCOL_MASK;
- val |= CXL_VSEC_PROTOCOL_256TB | CXL_VSEC_PROTOCOL_ENABLE;
- if ((rc = CXL_WRITE_VSEC_MODE_CONTROL(dev, vsec, val))) {
- dev_err(&dev->dev, "failed to enable CXL protocol: %i", rc);
- return rc;
+
+ if (mode == CXL_BIMODE_PCI) {
+ if (!(val & CXL_VSEC_PROTOCOL_ENABLE)) {
+ dev_info(&dev->dev, "Card is already in PCI mode\n");
+ return 0;
+ }
+ /*
+ * TODO: Before it's safe to switch the card back to PCI mode
+ * we need to disable the CAPP and make sure any cachelines the
+ * card holds have been flushed out. Needs skiboot support.
+ */
+ dev_WARN(&dev->dev, "CXL mode switch to PCI unsupported!\n");
+ return -EIO;
}
+
+ if (val & CXL_VSEC_PROTOCOL_ENABLE) {
+ dev_info(&dev->dev, "Card is already in CXL mode\n");
+ return 0;
+ }
+
+ dev_info(&dev->dev, "Card is in PCI mode, scheduling kernel thread "
+ "to switch to CXL mode\n");
+
+ work = kmalloc(sizeof(struct cxl_switch_work), GFP_KERNEL);
+ if (!work)
+ return -ENOMEM;
+
+ pci_dev_get(dev);
+ work->dev = dev;
+ work->vsec = vsec;
+ work->mode = mode;
+ INIT_WORK(&work->work, switch_card_to_cxl);
+
+ schedule_work(&work->work);
+
/*
- * The CAIA spec (v0.12 11.6 Bi-modal Device Support) states
- * we must wait 100ms after this mode switch before touching
- * PCIe config space.
+ * We return a failure now to abort the driver init. Once the
+ * link has been cycled and the card is in cxl mode we will
+ * come back (possibly using the generic cxl driver), but
+ * return success as the card should then be in cxl mode.
+ *
+ * TODO: What if the card comes back in PCI mode even after
+ * the switch? Don't want to spin endlessly.
*/
- msleep(100);
+ return -EBUSY;
+}
+EXPORT_SYMBOL_GPL(cxl_check_and_switch_mode);
+
+#endif /* CONFIG_CXL_BIMODAL */
+
+static int setup_cxl_protocol_area(struct pci_dev *dev)
+{
+ u8 val;
+ int rc;
+ int vsec = find_cxl_vsec(dev);
+
+ if (!vsec) {
+ dev_info(&dev->dev, "CXL VSEC not found\n");
+ return -ENODEV;
+ }
+
+ rc = CXL_READ_VSEC_MODE_CONTROL(dev, vsec, &val);
+ if (rc) {
+ dev_err(&dev->dev, "Failed to read current mode control: %i\n", rc);
+ return rc;
+ }
+
+ if (!(val & CXL_VSEC_PROTOCOL_ENABLE)) {
+ dev_err(&dev->dev, "Card not in CAPI mode!\n");
+ return -EIO;
+ }
+
+ if ((val & CXL_VSEC_PROTOCOL_MASK) != CXL_VSEC_PROTOCOL_256TB) {
+ val &= ~CXL_VSEC_PROTOCOL_MASK;
+ val |= CXL_VSEC_PROTOCOL_256TB;
+ rc = CXL_WRITE_VSEC_MODE_CONTROL(dev, vsec, val);
+ if (rc) {
+ dev_err(&dev->dev, "Failed to set CXL protocol area: %i\n", rc);
+ return rc;
+ }
+ }
return 0;
}
@@ -1249,7 +1449,7 @@ static int cxl_configure_adapter(struct cxl *adapter, struct pci_dev *dev)
if ((rc = setup_cxl_bars(dev)))
return rc;
- if ((rc = switch_card_to_cxl(dev)))
+ if ((rc = setup_cxl_protocol_area(dev)))
return rc;
if ((rc = cxl_update_image_control(adapter)))
@@ -39,6 +39,31 @@
bool cxl_slot_is_supported(struct pci_dev *dev, int flags);
+#define CXL_BIMODE_CXL 1
+#define CXL_BIMODE_PCI 2
+
+/*
+ * Check the mode that the given bi-modal CXL adapter is currently in and
+ * change it if necessary. This does not apply to AFU drivers.
+ *
+ * If the mode matches the requested mode this function will return 0 - if the
+ * driver was expecting the generic CXL driver to have bound to the adapter and
+ * it gets this return value it should fail the probe function to give the CXL
+ * driver a chance to probe it.
+ *
+ * If the mode does not match it will start a background task to unplug the
+ * device from Linux and switch its mode, and will return -EBUSY. At this
+ * point the calling driver should make sure it has released the device and
+ * fail its probe function.
+ *
+ * The offset of the CXL VSEC can be provided to this function. If 0 is passed,
+ * this function will search for a CXL VSEC with ID 0x1280 and return -ENODEV
+ * if it is not found.
+ */
+#ifdef CONFIG_CXL_BIMODAL
+int cxl_check_and_switch_mode(struct pci_dev *dev, int mode, int vsec);
+#endif
+
/* Get the AFU associated with a pci_dev */
struct cxl_afu *cxl_pci_to_afu(struct pci_dev *dev);