Date:   Tue, 16 May 2017 11:14:50 -0700
From:   Felix Manlunas <felix.manlunas@...ium.com>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org, raghu.vatsavayi@...ium.com,
        derek.chickles@...ium.com, satananda.burla@...ium.com,
        ricardo.farrington@...ium.com
Subject: [PATCH net-next] liquidio: fix insmod failure when multiple NICs are
 plugged in

From: Rick Farrington <ricardo.farrington@...ium.com>

When multiple liquidio NICs are plugged in, the first insmod of the PF
driver succeeds.  But after an rmmod, a subsequent insmod fails.  Reason is
during rmmod, the PF driver resets the Octeon of only one of the NICs; it
neglects to reset the Octeons of the other NICs.

Fix the insmod failure by adding the missing Octeon resets at rmmod.  Keep
a per-NIC refcount that indicates the number of active PFs in a given NIC.
When the refcount goes to zero, then reset the Octeon of that NIC.

Signed-off-by: Rick Farrington <ricardo.farrington@...ium.com>
Signed-off-by: Felix Manlunas <felix.manlunas@...ium.com>
---
 drivers/net/ethernet/cavium/liquidio/lio_main.c    | 21 +++++-
 .../net/ethernet/cavium/liquidio/octeon_device.c   | 87 ++++++++++++++++++++--
 .../net/ethernet/cavium/liquidio/octeon_device.h   | 25 +++++++
 3 files changed, 123 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/cavium/liquidio/lio_main.c b/drivers/net/ethernet/cavium/liquidio/lio_main.c
index 927617c..360ddc8 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_main.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_main.c
@@ -1421,7 +1421,7 @@ static bool fw_type_is_none(void)
  */
 static void octeon_destroy_resources(struct octeon_device *oct)
 {
-	int i;
+	int i, refcount;
 	struct msix_entry *msix_entries;
 	struct octeon_device_priv *oct_priv =
 		(struct octeon_device_priv *)oct->priv;
@@ -1556,10 +1556,14 @@ static void octeon_destroy_resources(struct octeon_device *oct)
 
 		/* fallthrough */
 	case OCT_DEV_PCI_MAP_DONE:
+		refcount = octeon_deregister_device(oct);
+
 		if (!fw_type_is_none()) {
-			/* Soft reset the octeon device before exiting */
-			if (!OCTEON_CN23XX_PF(oct) ||
-			    (OCTEON_CN23XX_PF(oct) && !oct->octeon_id))
+			/* Soft reset the octeon device before exiting.
+			 * Implementation note: here, we reset the device
+			 * if it is a CN6XXX OR the last CN23XX device.
+			 */
+			if (OCTEON_CN6XXX(oct) || !refcount)
 				oct->fn_list.soft_reset(oct);
 		}
 
@@ -4511,6 +4515,15 @@ static int octeon_device_init(struct octeon_device *octeon_dev)
 
 	atomic_set(&octeon_dev->status, OCT_DEV_PCI_MAP_DONE);
 
+	/* Only add a reference after setting status 'OCT_DEV_PCI_MAP_DONE',
+	 * since that is what is required for the reference to be removed
+	 * during de-initialization (see 'octeon_destroy_resources').
+	 */
+	octeon_register_device(octeon_dev, octeon_dev->pci_dev->bus->number,
+			       PCI_SLOT(octeon_dev->pci_dev->devfn),
+			       PCI_FUNC(octeon_dev->pci_dev->devfn),
+			       true);
+
 	octeon_dev->app_mode = CVM_DRV_INVALID_APP;
 
 	if (OCTEON_CN23XX_PF(octeon_dev)) {
diff --git a/drivers/net/ethernet/cavium/liquidio/octeon_device.c b/drivers/net/ethernet/cavium/liquidio/octeon_device.c
index e21b477..3cc5667 100644
--- a/drivers/net/ethernet/cavium/liquidio/octeon_device.c
+++ b/drivers/net/ethernet/cavium/liquidio/octeon_device.c
@@ -543,7 +543,11 @@ static char oct_dev_app_str[CVM_DRV_APP_COUNT + 1][32] = {
 	"BASE", "NIC", "UNKNOWN"};
 
 static struct octeon_device *octeon_device[MAX_OCTEON_DEVICES];
+static atomic_t adapter_refcounts[MAX_OCTEON_DEVICES];
+
 static u32 octeon_device_count;
+/* locks device array (i.e. octeon_device[]) */
+spinlock_t octeon_devices_lock;
 
 static struct octeon_core_setup core_setup[MAX_OCTEON_DEVICES];
 
@@ -561,6 +565,7 @@ void octeon_init_device_list(int conf_type)
 	memset(octeon_device, 0, (sizeof(void *) * MAX_OCTEON_DEVICES));
 	for (i = 0; i <  MAX_OCTEON_DEVICES; i++)
 		oct_set_config_info(i, conf_type);
+	spin_lock_init(&octeon_devices_lock);
 }
 
 static void *__retrieve_octeon_config_info(struct octeon_device *oct,
@@ -720,23 +725,27 @@ struct octeon_device *octeon_allocate_device(u32 pci_id,
 	u32 oct_idx = 0;
 	struct octeon_device *oct = NULL;
 
+	spin_lock(&octeon_devices_lock);
+
 	for (oct_idx = 0; oct_idx < MAX_OCTEON_DEVICES; oct_idx++)
 		if (!octeon_device[oct_idx])
 			break;
 
-	if (oct_idx == MAX_OCTEON_DEVICES)
-		return NULL;
+	if (oct_idx < MAX_OCTEON_DEVICES) {
+		oct = octeon_allocate_device_mem(pci_id, priv_size);
+		if (oct) {
+			octeon_device_count++;
+			octeon_device[oct_idx] = oct;
+		}
+	}
 
-	oct = octeon_allocate_device_mem(pci_id, priv_size);
+	spin_unlock(&octeon_devices_lock);
 	if (!oct)
 		return NULL;
 
 	spin_lock_init(&oct->pci_win_lock);
 	spin_lock_init(&oct->mem_access_lock);
 
-	octeon_device_count++;
-	octeon_device[oct_idx] = oct;
-
 	oct->octeon_id = oct_idx;
 	snprintf(oct->device_name, sizeof(oct->device_name),
 		 "LiquidIO%d", (oct->octeon_id));
@@ -744,6 +753,72 @@ struct octeon_device *octeon_allocate_device(u32 pci_id,
 	return oct;
 }
 
+/** Register a device's bus location at initialization time.
+ *  @param octeon_dev - pointer to the octeon device structure.
+ *  @param bus        - PCIe bus #
+ *  @param dev        - PCIe device #
+ *  @param func       - PCIe function #
+ *  @param is_pf      - TRUE for PF, FALSE for VF
+ *  @return reference count of device's adapter
+ */
+int octeon_register_device(struct octeon_device *oct,
+			   int bus, int dev, int func, int is_pf)
+{
+	int idx, refcount;
+
+	oct->loc.bus = bus;
+	oct->loc.dev = dev;
+	oct->loc.func = func;
+
+	oct->adapter_refcount = &adapter_refcounts[oct->octeon_id];
+	atomic_set(oct->adapter_refcount, 0);
+
+	spin_lock(&octeon_devices_lock);
+	for (idx = (int)oct->octeon_id - 1; idx >= 0; idx--) {
+		if (!octeon_device[idx]) {
+			dev_err(&oct->pci_dev->dev,
+				"%s: Internal driver error, missing dev",
+				__func__);
+			spin_unlock(&octeon_devices_lock);
+			atomic_inc(oct->adapter_refcount);
+			return 1; /* here, refcount is guaranteed to be 1 */
+		}
+		/* if another device is at same bus/dev, use its refcounter */
+		if ((octeon_device[idx]->loc.bus == bus) &&
+		    (octeon_device[idx]->loc.dev == dev)) {
+			oct->adapter_refcount =
+				octeon_device[idx]->adapter_refcount;
+			break;
+		}
+	}
+	spin_unlock(&octeon_devices_lock);
+
+	atomic_inc(oct->adapter_refcount);
+	refcount = atomic_read(oct->adapter_refcount);
+
+	dev_dbg(&oct->pci_dev->dev, "%s: %02x:%02x:%d refcount %u", __func__,
+		oct->loc.bus, oct->loc.dev, oct->loc.func, refcount);
+
+	return refcount;
+}
+
+/** Deregister a device at de-initialization time.
+ *  @param octeon_dev - pointer to the octeon device structure.
+ *  @return reference count of device's adapter
+ */
+int octeon_deregister_device(struct octeon_device *oct)
+{
+	int refcount;
+
+	atomic_dec(oct->adapter_refcount);
+	refcount = atomic_read(oct->adapter_refcount);
+
+	dev_dbg(&oct->pci_dev->dev, "%s: %04d:%02d:%d refcount %u", __func__,
+		oct->loc.bus, oct->loc.dev, oct->loc.func, refcount);
+
+	return refcount;
+}
+
 int
 octeon_allocate_ioq_vector(struct octeon_device  *oct)
 {
diff --git a/drivers/net/ethernet/cavium/liquidio/octeon_device.h b/drivers/net/ethernet/cavium/liquidio/octeon_device.h
index 92f67de..c90ed48 100644
--- a/drivers/net/ethernet/cavium/liquidio/octeon_device.h
+++ b/drivers/net/ethernet/cavium/liquidio/octeon_device.h
@@ -544,6 +544,14 @@ struct octeon_device {
 	u32 tx_max_coalesced_frames;
 
 	bool cores_crashed;
+
+	struct {
+		int bus;
+		int dev;
+		int func;
+	} loc;
+
+	atomic_t *adapter_refcount; /* reference count of adapter */
 };
 
 #define  OCT_DRV_ONLINE 1
@@ -572,6 +580,23 @@ void octeon_free_device_mem(struct octeon_device *oct);
 struct octeon_device *octeon_allocate_device(u32 pci_id,
 					     u32 priv_size);
 
+/** Register a device's bus location at initialization time.
+ *  @param octeon_dev - pointer to the octeon device structure.
+ *  @param bus        - PCIe bus #
+ *  @param dev        - PCIe device #
+ *  @param func       - PCIe function #
+ *  @param is_pf      - TRUE for PF, FALSE for VF
+ *  @return reference count of device's adapter
+ */
+int octeon_register_device(struct octeon_device *oct,
+			   int bus, int dev, int func, int is_pf);
+
+/** Deregister a device at de-initialization time.
+ *  @param octeon_dev - pointer to the octeon device structure.
+ *  @return reference count of device's adapter
+ */
+int octeon_deregister_device(struct octeon_device *oct);
+
 /**  Initialize the driver's dispatch list which is a mix of a hash table
  *  and a linked list. This is done at driver load time.
  *  @param octeon_dev - pointer to the octeon device structure.

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