qeth: bridgeport support - basic control

Introduce functions to assign roles and check state of bridgeport-capable
HiperSocket devices, and sysfs attributes providing access to these
functions from userspace. Introduce udev events emitted when the state
of a bridgeport device changes.

Signed-off-by: Eugene Crosser <eugene.crosser@ru.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Reviewed-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/s390/net/qeth_l2_sys.c

@@ -0,0 +1,161 @@
+/*
+ *    Copyright IBM Corp. 2013
+ *    Author(s): Eugene Crosser <eugene.crosser@ru.ibm.com>
+ */
+
+#include <linux/slab.h>
+#include <asm/ebcdic.h>
+#include "qeth_l2.h"
+
+#define QETH_DEVICE_ATTR(_id, _name, _mode, _show, _store) \
+struct device_attribute dev_attr_##_id = __ATTR(_name, _mode, _show, _store)
+
+static int qeth_card_hw_is_reachable(struct qeth_card *card)
+{
+	return (card->state == CARD_STATE_SOFTSETUP) ||
+		(card->state == CARD_STATE_UP);
+}
+
+static ssize_t qeth_bridge_port_role_state_show(struct device *dev,
+				struct device_attribute *attr, char *buf,
+				int show_state)
+{
+	struct qeth_card *card = dev_get_drvdata(dev);
+	enum qeth_sbp_states state = QETH_SBP_STATE_INACTIVE;
+	int rc = 0;
+	char *word;
+
+	if (!card)
+		return -EINVAL;
+
+	mutex_lock(&card->conf_mutex);
+
+	if (qeth_card_hw_is_reachable(card) &&
+					card->options.sbp.supported_funcs)
+		rc = qeth_bridgeport_query_ports(card,
+			&card->options.sbp.role, &state);
+	if (!rc) {
+		if (show_state)
+			switch (state) {
+			case QETH_SBP_STATE_INACTIVE:
+				word = "inactive"; break;
+			case QETH_SBP_STATE_STANDBY:
+				word = "standby"; break;
+			case QETH_SBP_STATE_ACTIVE:
+				word = "active"; break;
+			default:
+				rc = -EIO;
+			}
+		else
+			switch (card->options.sbp.role) {
+			case QETH_SBP_ROLE_NONE:
+				word = "none"; break;
+			case QETH_SBP_ROLE_PRIMARY:
+				word = "primary"; break;
+			case QETH_SBP_ROLE_SECONDARY:
+				word = "secondary"; break;
+			default:
+				rc = -EIO;
+			}
+		if (rc)
+			QETH_CARD_TEXT_(card, 2, "SBP%02x:%02x",
+				card->options.sbp.role, state);
+		else
+			rc = sprintf(buf, "%s\n", word);
+	}
+
+	mutex_unlock(&card->conf_mutex);
+
+	return rc;
+}
+
+static ssize_t qeth_bridge_port_role_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	return qeth_bridge_port_role_state_show(dev, attr, buf, 0);
+}
+
+static ssize_t qeth_bridge_port_role_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct qeth_card *card = dev_get_drvdata(dev);
+	int rc = 0;
+	enum qeth_sbp_roles role;
+
+	if (!card)
+		return -EINVAL;
+	if (sysfs_streq(buf, "primary"))
+		role = QETH_SBP_ROLE_PRIMARY;
+	else if (sysfs_streq(buf, "secondary"))
+		role = QETH_SBP_ROLE_SECONDARY;
+	else if (sysfs_streq(buf, "none"))
+		role = QETH_SBP_ROLE_NONE;
+	else
+		return -EINVAL;
+
+	mutex_lock(&card->conf_mutex);
+
+	if (qeth_card_hw_is_reachable(card)) {
+		rc = qeth_bridgeport_setrole(card, role);
+		if (!rc)
+			card->options.sbp.role = role;
+	} else
+		card->options.sbp.role = role;
+
+	mutex_unlock(&card->conf_mutex);
+
+	return rc ? rc : count;
+}
+
+static DEVICE_ATTR(bridge_role, 0644, qeth_bridge_port_role_show,
+		   qeth_bridge_port_role_store);
+
+static ssize_t qeth_bridge_port_state_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	return qeth_bridge_port_role_state_show(dev, attr, buf, 1);
+}
+
+static DEVICE_ATTR(bridge_state, 0644, qeth_bridge_port_state_show,
+		   NULL);
+
+static struct attribute *qeth_l2_bridgeport_attrs[] = {
+	&dev_attr_bridge_role.attr,
+	&dev_attr_bridge_state.attr,
+	NULL,
+};
+
+static struct attribute_group qeth_l2_bridgeport_attr_group = {
+	.attrs = qeth_l2_bridgeport_attrs,
+};
+
+int qeth_l2_create_device_attributes(struct device *dev)
+{
+	return sysfs_create_group(&dev->kobj, &qeth_l2_bridgeport_attr_group);
+}
+
+void qeth_l2_remove_device_attributes(struct device *dev)
+{
+	sysfs_remove_group(&dev->kobj, &qeth_l2_bridgeport_attr_group);
+}
+
+/**
+ * qeth_l2_setup_bridgeport_attrs() - set/restore attrs when turning online.
+ * @card:			      qeth_card structure pointer
+ *
+ * Note: this function is called with conf_mutex held by the caller
+ */
+void qeth_l2_setup_bridgeport_attrs(struct qeth_card *card)
+{
+	if (!card)
+		return;
+	if (!card->options.sbp.supported_funcs)
+		return;
+	if (card->options.sbp.role != QETH_SBP_ROLE_NONE) {
+		/* Conditional to avoid spurious error messages */
+		qeth_bridgeport_setrole(card, card->options.sbp.role);
+		/* Let the callback function refresh the stored role value. */
+		qeth_bridgeport_query_ports(card,
+			&card->options.sbp.role, NULL);
+	}
+}