s390/pci: implement hotplug notifications

When the availability of a pci function has changed by means
outside of our control we receive an availability event.
Implement/improve the handling of these notifications.
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/pci/pci_event.c

@@ -11,6 +11,7 @@
 #include <linux/kernel.h>
 #include <linux/pci.h>
 #include <asm/pci_debug.h>
+#include <asm/sclp.h>
 
 /* Content Code Description for PCI Function Error */
 struct zpci_ccdf_err {
@@ -42,10 +43,27 @@ struct zpci_ccdf_avail {
 	u16 pec;			/* PCI event code */
 } __packed;
 
-static void zpci_event_log_avail(struct zpci_ccdf_avail *ccdf)
+void zpci_event_error(void *data)
 {
+	struct zpci_ccdf_err *ccdf = data;
+	struct zpci_dev *zdev = get_zdev_by_fid(ccdf->fid);
+
+	zpci_err("error CCDF:\n");
+	zpci_err_hex(ccdf, sizeof(*ccdf));
+
+	if (!zdev)
+		return;
+
+	pr_err("%s: Event 0x%x reports an error for PCI function 0x%x\n",
+	       pci_name(zdev->pdev), ccdf->pec, ccdf->fid);
+}
+
+void zpci_event_availability(void *data)
+{
+	struct zpci_ccdf_avail *ccdf = data;
 	struct zpci_dev *zdev = get_zdev_by_fid(ccdf->fid);
 	struct pci_dev *pdev = zdev ? zdev->pdev : NULL;
+	int ret;
 
 	pr_info("%s: Event 0x%x reconfigured PCI function 0x%x\n",
 		pdev ? pci_name(pdev) : "n/a", ccdf->pec, ccdf->fid);
@@ -53,36 +71,47 @@ static void zpci_event_log_avail(struct zpci_ccdf_avail *ccdf)
 	zpci_err_hex(ccdf, sizeof(*ccdf));
 
 	switch (ccdf->pec) {
-	case 0x0301:
-		zpci_enable_device(zdev);
+	case 0x0301: /* Standby -> Configured */
+		if (!zdev || zdev->state == ZPCI_FN_STATE_CONFIGURED)
 			break;
-	case 0x0302:
-		clp_add_pci_device(ccdf->fid, ccdf->fh, 0);
+		zdev->state = ZPCI_FN_STATE_CONFIGURED;
+		ret = zpci_enable_device(zdev);
+		if (ret)
 			break;
-	case 0x0306:
-		clp_rescan_pci_devices();
+		pci_rescan_bus(zdev->bus);
 		break;
-	default:
+	case 0x0302: /* Reserved -> Standby */
+		clp_add_pci_device(ccdf->fid, ccdf->fh, 0);
 		break;
-	}
-}
+	case 0x0303: /* Deconfiguration requested */
+		if (pdev)
+			pci_stop_and_remove_bus_device(pdev);
 
-void zpci_event_error(void *data)
-{
-	struct zpci_ccdf_err *ccdf = data;
-	struct zpci_dev *zdev = get_zdev_by_fid(ccdf->fid);
-
-	zpci_err("error CCDF:\n");
-	zpci_err_hex(ccdf, sizeof(*ccdf));
+		ret = zpci_disable_device(zdev);
+		if (ret)
+			break;
 
-	if (!zdev)
-		return;
+		ret = sclp_pci_deconfigure(zdev->fid);
+		zpci_dbg(3, "deconf fid:%x, rc:%d\n", zdev->fid, ret);
+		if (!ret)
+			zdev->state = ZPCI_FN_STATE_STANDBY;
 
-	pr_err("%s: Event 0x%x reports an error for PCI function 0x%x\n",
-	       pci_name(zdev->pdev), ccdf->pec, ccdf->fid);
-}
+		break;
+	case 0x0304: /* Configured -> Standby */
+		if (pdev)
+			pci_stop_and_remove_bus_device(pdev);
 
-void zpci_event_availability(void *data)
-{
-	zpci_event_log_avail(data);
+		zpci_disable_device(zdev);
+		zdev->state = ZPCI_FN_STATE_STANDBY;
+		break;
+	case 0x0306: /* 0x308 or 0x302 for multiple devices */
+		clp_rescan_pci_devices();
+		break;
+	case 0x0308: /* Standby -> Reserved */
+		pci_stop_root_bus(zdev->bus);
+		pci_remove_root_bus(zdev->bus);
+		break;
+	default:
+		break;
+	}
 }