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);
         }
 }