cxl: Report the tunneled operations status

Failure to synchronize the tunneled operations does not prevent
the initialization of the cxl card. This patch reports the tunneled
operations status via /sys.

Signed-off-by: Philippe Bergheaud <felix@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Documentation/ABI/testing/sysfs-class-cxl

@@ -244,3 +244,11 @@ Description:    read only
                 Returns 1 if the psl timebase register is synchronized
                 with the core timebase register, 0 otherwise.
 Users:          https://github.com/ibm-capi/libcxl
+
+What:           /sys/class/cxl/<card>/tunneled_ops_supported
+Date:           May 2018
+Contact:        linuxppc-dev@lists.ozlabs.org
+Description:    read only
+                Returns 1 if tunneled operations are supported in capi mode,
+                0 otherwise.
+Users:          https://github.com/ibm-capi/libcxl

drivers/misc/cxl/cxl.h

@@ -717,6 +717,7 @@ struct cxl {
 	bool perst_select_user;
 	bool perst_same_image;
 	bool psl_timebase_synced;
+	bool tunneled_ops_supported;
 
 	/*
 	 * number of contexts mapped on to this card. Possible values are:

drivers/misc/cxl/pci.c

@@ -1742,9 +1742,14 @@ static int cxl_configure_adapter(struct cxl *adapter, struct pci_dev *dev)
 	/* Required for devices using CAPP DMA mode, harmless for others */
 	pci_set_master(dev);
 
-	if (cxl_is_power9())
+	adapter->tunneled_ops_supported = false;
+
+	if (cxl_is_power9()) {
 		if (pnv_pci_set_tunnel_bar(dev, 0x00020000E0000000ull, 1))
 			dev_info(&dev->dev, "Tunneled operations unsupported\n");
+		else
+			adapter->tunneled_ops_supported = true;
+	}
 
 	if ((rc = pnv_phb_to_cxl_mode(dev, adapter->native->sl_ops->capi_mode)))
 		goto err;

drivers/misc/cxl/sysfs.c

@@ -78,6 +78,15 @@ static ssize_t psl_timebase_synced_show(struct device *device,
 	return scnprintf(buf, PAGE_SIZE, "%i\n", adapter->psl_timebase_synced);
 }
 
+static ssize_t tunneled_ops_supported_show(struct device *device,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct cxl *adapter = to_cxl_adapter(device);
+
+	return scnprintf(buf, PAGE_SIZE, "%i\n", adapter->tunneled_ops_supported);
+}
+
 static ssize_t reset_adapter_store(struct device *device,
 				   struct device_attribute *attr,
 				   const char *buf, size_t count)
@@ -183,6 +192,7 @@ static struct device_attribute adapter_attrs[] = {
 	__ATTR_RO(base_image),
 	__ATTR_RO(image_loaded),
 	__ATTR_RO(psl_timebase_synced),
+	__ATTR_RO(tunneled_ops_supported),
 	__ATTR_RW(load_image_on_perst),
 	__ATTR_RW(perst_reloads_same_image),
 	__ATTR(reset, S_IWUSR, NULL, reset_adapter_store),