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>

3 files changed, 163 insertions, 0 deletions

diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index 927dba9911ed..d19fcae8a7c0 100644
--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -69,6 +69,7 @@ struct slot {
         struct hotplug_slot *hotplug_slot;
         struct list_head        slot_list;
         char name[SLOT_NAME_SIZE];
+        unsigned long last_emi_toggle;
 };
 
 struct event_info {
@@ -138,6 +139,7 @@ struct controller {
 #define ATTN_LED_PRSN   0x00000008
 #define PWR_LED_PRSN    0x00000010
 #define HP_SUPR_RM_SUP  0x00000020
+#define EMI_PRSN        0x00020000
 
 #define ATTN_BUTTN(cap)         (cap & ATTN_BUTTN_PRSN)
 #define POWER_CTRL(cap)         (cap & PWR_CTRL_PRSN)
@@ -145,6 +147,7 @@ struct controller {
 #define ATTN_LED(cap)           (cap & ATTN_LED_PRSN)
 #define PWR_LED(cap)            (cap & PWR_LED_PRSN) 
 #define HP_SUPR_RM(cap)         (cap & HP_SUPR_RM_SUP)
+#define EMI(cap)                (cap & EMI_PRSN)
 
 extern int pciehp_event_start_thread(void);
 extern void pciehp_event_stop_thread(void);
@@ -182,6 +185,8 @@ struct hpc_ops {
         int (*set_attention_status)(struct slot *slot, u8 status);
         int (*get_latch_status)(struct slot *slot, u8 *status);
         int (*get_adapter_status)(struct slot *slot, u8 *status);
+        int (*get_emi_status)(struct slot *slot, u8 *status);
+        int (*toggle_emi)(struct slot *slot);
         int (*get_max_bus_speed)(struct slot *slot, enum pci_bus_speed *speed);
         int (*get_cur_bus_speed)(struct slot *slot, enum pci_bus_speed *speed);
         int (*get_max_lnk_width)(struct slot *slot, enum pcie_link_width *val);
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);
         }
 }
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index eb1862b50bb1..fbc64aa2dd68 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -35,6 +35,7 @@
 #include <linux/timer.h>
 #include <linux/pci.h>
 #include <linux/interrupt.h>
+#include <linux/time.h>
 
 #include "../pci.h"
 #include "pciehp.h"
@@ -192,6 +193,7 @@ static inline int pciehp_writel(struct controller *ctrl, int reg, u32 value)
 #define ATTN_LED_CTRL                   0x00C0
 #define PWR_LED_CTRL                    0x0300
 #define PWR_CTRL                        0x0400
+#define EMI_CTRL                        0x0800
 
 /* Attention indicator and Power indicator states */
 #define LED_ON          0x01
@@ -202,6 +204,10 @@ static inline int pciehp_writel(struct controller *ctrl, int reg, u32 value)
 #define POWER_ON        0
 #define POWER_OFF       0x0400
 
+/* EMI Status defines */
+#define EMI_DISENGAGED  0
+#define EMI_ENGAGED     1
+
 /* Field definitions in Slot Status Register */
 #define ATTN_BUTTN_PRESSED      0x0001
 #define PWR_FAULT_DETECTED      0x0002
@@ -210,6 +216,8 @@ static inline int pciehp_writel(struct controller *ctrl, int reg, u32 value)
 #define CMD_COMPLETED           0x0010
 #define MRL_STATE               0x0020
 #define PRSN_STATE              0x0040
+#define EMI_STATE               0x0080
+#define EMI_STATUS_BIT          7
 
 static spinlock_t hpc_event_lock;
 
@@ -474,6 +482,51 @@ static int hpc_query_power_fault(struct slot *slot)
         return pwr_fault;
 }
 
+static int hpc_get_emi_status(struct slot *slot, u8 *status)
+{
+        struct controller *ctrl = slot->ctrl;
+        u16 slot_status;
+        int retval = 0;
+
+        DBG_ENTER_ROUTINE
+
+        retval = pciehp_readw(ctrl, SLOTSTATUS, &slot_status);
+        if (retval) {
+                err("%s : Cannot check EMI status\n", __FUNCTION__);
+                return retval;
+        }
+        *status = (slot_status & EMI_STATE) >> EMI_STATUS_BIT;
+
+        DBG_LEAVE_ROUTINE
+        return retval;
+}
+
+static int hpc_toggle_emi(struct slot *slot)
+{
+        struct controller *ctrl = slot->ctrl;
+        u16 slot_cmd = 0;
+        u16 slot_ctrl;
+        int rc = 0;
+
+        DBG_ENTER_ROUTINE
+
+        rc = pciehp_readw(ctrl, SLOTCTRL, &slot_ctrl);
+        if (rc) {
+                err("%s : hp_register_read_word SLOT_CTRL failed\n",
+                        __FUNCTION__);
+                return rc;
+        }
+
+        slot_cmd = (slot_ctrl | EMI_CTRL);
+        if (!pciehp_poll_mode)
+                slot_cmd = slot_cmd | HP_INTR_ENABLE;
+
+        pcie_write_cmd(slot, slot_cmd);
+        slot->last_emi_toggle = get_seconds();
+        DBG_LEAVE_ROUTINE
+        return rc;
+}
+
 static int hpc_set_attention_status(struct slot *slot, u8 value)
 {
         struct controller *ctrl = slot->ctrl;
@@ -1009,6 +1062,8 @@ static struct hpc_ops pciehp_hpc_ops = {
         .get_attention_status           = hpc_get_attention_status,
         .get_latch_status               = hpc_get_latch_status,
         .get_adapter_status             = hpc_get_adapter_status,
+        .get_emi_status                 = hpc_get_emi_status,
+        .toggle_emi                     = hpc_toggle_emi,
 
         .get_max_bus_speed              = hpc_get_max_lnk_speed,
         .get_cur_bus_speed              = hpc_get_cur_lnk_speed,