PCIEHP: Add Electro Mechanical Interlock (EMI) support to the PCIE hotplug driver.

Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 103 insertions, 0 deletions

diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
index f7b8e0504fec..a92eda6e02f6 100644
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -34,6 +34,7 @@
 #include <linux/pci.h>
 #include "pciehp.h"
 #include <linux/interrupt.h>
+#include <linux/time.h>
 
 /* Global variables */
 int pciehp_debug;
@@ -87,6 +88,95 @@ static struct hotplug_slot_ops pciehp_hotplug_slot_ops = {
   	.get_cur_bus_speed =	get_cur_bus_speed,
 };
 
+/*
+ * Check the status of the Electro Mechanical Interlock (EMI)
+ */
+static int get_lock_status(struct hotplug_slot *hotplug_slot, u8 *value)
+{
+	struct slot *slot = hotplug_slot->private;
+	return (slot->hpc_ops->get_emi_status(slot, value));
+}
+
+/*
+ * sysfs interface for the Electro Mechanical Interlock (EMI)
+ * 1 == locked, 0 == unlocked
+ */
+static ssize_t lock_read_file(struct hotplug_slot *slot, char *buf)
+{
+	int retval;
+	u8 value;
+
+	retval = get_lock_status(slot, &value);
+	if (retval)
+		goto lock_read_exit;
+	retval = sprintf (buf, "%d\n", value);
+
+lock_read_exit:
+	return retval;
+}
+
+/*
+ * Change the status of the Electro Mechanical Interlock (EMI)
+ * This is a toggle - in addition there must be at least 1 second
+ * in between toggles.
+ */
+static int set_lock_status(struct hotplug_slot *hotplug_slot, u8 status)
+{
+	struct slot *slot = hotplug_slot->private;
+	int retval;
+	u8 value;
+
+	mutex_lock(&slot->ctrl->crit_sect);
+
+	/* has it been >1 sec since our last toggle? */
+	if ((get_seconds() - slot->last_emi_toggle) < 1)
+		return -EINVAL;
+
+	/* see what our current state is */
+	retval = get_lock_status(hotplug_slot, &value);
+	if (retval || (value == status))
+		goto set_lock_exit;
+
+	slot->hpc_ops->toggle_emi(slot);
+set_lock_exit:
+	mutex_unlock(&slot->ctrl->crit_sect);
+	return 0;
+}
+
+/*
+ * sysfs interface which allows the user to toggle the Electro Mechanical
+ * Interlock.  Valid values are either 0 or 1.  0 == unlock, 1 == lock
+ */
+static ssize_t lock_write_file(struct hotplug_slot *slot, const char *buf,
+		size_t count)
+{
+	unsigned long llock;
+	u8 lock;
+	int retval = 0;
+
+	llock = simple_strtoul(buf, NULL, 10);
+	lock = (u8)(llock & 0xff);
+
+	switch (lock) {
+		case 0:
+		case 1:
+			retval = set_lock_status(slot, lock);
+			break;
+		default:
+			err ("%d is an invalid lock value\n", lock);
+			retval = -EINVAL;
+	}
+	if (retval)
+		return retval;
+	return count;
+}
+
+static struct hotplug_slot_attribute hotplug_slot_attr_lock = {
+	.attr = {.name = "lock", .mode = S_IFREG | S_IRUGO | S_IWUSR},
+	.show = lock_read_file,
+	.store = lock_write_file
+};
+
 /**
  * release_slot - free up the memory used by a slot
  * @hotplug_slot: slot to free
@@ -159,6 +249,16 @@ static int init_slots(struct controller *ctrl)
 			err ("pci_hp_register failed with error %d\n", retval);
 			goto error_info;
 		}
+		/* create additional sysfs entries */
+		if (EMI(ctrl->ctrlcap)) {
+			retval = sysfs_create_file(&hotplug_slot->kobj,
+				&hotplug_slot_attr_lock.attr);
+			if (retval) {
+				pci_hp_deregister(hotplug_slot);
+				err("cannot create additional sysfs entries\n");
+				goto error_info;
+			}
+		}
 
 		list_add(&slot->slot_list, &ctrl->slot_list);
 	}
@@ -183,6 +283,9 @@ static void cleanup_slots(struct controller *ctrl)
 	list_for_each_safe(tmp, next, &ctrl->slot_list) {
 		slot = list_entry(tmp, struct slot, slot_list);
 		list_del(&slot->slot_list);
+		if (EMI(ctrl->ctrlcap))
+			sysfs_remove_file(&slot->hotplug_slot->kobj,
+				&hotplug_slot_attr_lock.attr);
 		pci_hp_deregister(slot->hotplug_slot);
 	}
 }