rapidio/tsi721: fix locking in OB_MSG processing

- Add spinlock protection into outbound message queuing routine.

- Change outbound message interrupt handler to avoid deadlock when
  calling registered callback routine.

- Allow infinite retries for outbound messages to avoid retry threshold
  error signaling in systems with nodes that have slow message receive
  queue processing.

Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Andre van Herk <andre.van.herk@prodrive-technologies.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 30 insertions, 12 deletions

diff --git a/drivers/rapidio/devices/tsi721.c b/drivers/rapidio/devices/tsi721.c
index 5e1d52674e17..822fd4bebf75 100644
--- a/drivers/rapidio/devices/tsi721.c
+++ b/drivers/rapidio/devices/tsi721.c
@@ -1453,11 +1453,14 @@ tsi721_add_outb_message(struct rio_mport *mport, struct rio_dev *rdev, int mbox,
         struct tsi721_device *priv = mport->priv;
         struct tsi721_omsg_desc *desc;
         u32 tx_slot;
+        unsigned long flags;
 
         if (!priv->omsg_init[mbox] ||
             len > TSI721_MSG_MAX_SIZE || len < 8)
                 return -EINVAL;
 
+        spin_lock_irqsave(&priv->omsg_ring[mbox].lock, flags);
+
         tx_slot = priv->omsg_ring[mbox].tx_slot;
 
         /* Copy copy message into transfer buffer */
@@ -1469,9 +1472,11 @@ tsi721_add_outb_message(struct rio_mport *mport, struct rio_dev *rdev, int mbox,
         /* Build descriptor associated with buffer */
         desc = priv->omsg_ring[mbox].omd_base;
         desc[tx_slot].type_id = cpu_to_le32((DTYPE4 << 29) | rdev->destid);
+#ifdef TSI721_OMSG_DESC_INT
+        /* Request IOF_DONE interrupt generation for each N-th frame in queue */
         if (tx_slot % 4 == 0)
                 desc[tx_slot].type_id |= cpu_to_le32(TSI721_OMD_IOF);
-
+#endif
         desc[tx_slot].msg_info =
                 cpu_to_le32((mport->sys_size << 26) | (mbox << 22) |
                             (0xe << 12) | (len & 0xff8));
@@ -1497,6 +1502,8 @@ tsi721_add_outb_message(struct rio_mport *mport, struct rio_dev *rdev, int mbox,
                 priv->regs + TSI721_OBDMAC_DWRCNT(mbox));
         ioread32(priv->regs + TSI721_OBDMAC_DWRCNT(mbox));
 
+        spin_unlock_irqrestore(&priv->omsg_ring[mbox].lock, flags);
+
         return 0;
 }
 
@@ -1511,6 +1518,9 @@ static void tsi721_omsg_handler(struct tsi721_device *priv, int ch)
 {
         u32 omsg_int;
         struct rio_mport *mport = &priv->mport;
+        void *dev_id = NULL;
+        u32 tx_slot = 0xffffffff;
+        int do_callback = 0;
 
         spin_lock(&priv->omsg_ring[ch].lock);
 
@@ -1524,7 +1534,6 @@ static void tsi721_omsg_handler(struct tsi721_device *priv, int ch)
                 u32 srd_ptr;
                 u64 *sts_ptr, last_ptr = 0, prev_ptr = 0;
                 int i, j;
-                u32 tx_slot;
 
                 /*
                  * Find last successfully processed descriptor
@@ -1574,14 +1583,19 @@ static void tsi721_omsg_handler(struct tsi721_device *priv, int ch)
                                 goto no_sts_update;
                 }
 
+                if (tx_slot >= priv->omsg_ring[ch].size)
+                        dev_dbg(&priv->pdev->dev,
+                                  "OB_MSG tx_slot=%x > size=%x",
+                                  tx_slot, priv->omsg_ring[ch].size);
+                WARN_ON(tx_slot >= priv->omsg_ring[ch].size);
+
                 /* Move slot index to the next message to be sent */
                 ++tx_slot;
                 if (tx_slot == priv->omsg_ring[ch].size)
                         tx_slot = 0;
-                BUG_ON(tx_slot >= priv->omsg_ring[ch].size);
-                mport->outb_msg[ch].mcback(mport,
-                                priv->omsg_ring[ch].dev_id, ch,
-                                tx_slot);
+
+                dev_id = priv->omsg_ring[ch].dev_id;
+                do_callback = 1;
         }
 
 no_sts_update:
@@ -1597,15 +1611,15 @@ no_sts_update:
 
                 iowrite32(TSI721_OBDMAC_INT_ERROR,
                                 priv->regs + TSI721_OBDMAC_INT(ch));
-                iowrite32(TSI721_OBDMAC_CTL_INIT,
+                iowrite32(TSI721_OBDMAC_CTL_RETRY_THR | TSI721_OBDMAC_CTL_INIT,
                                 priv->regs + TSI721_OBDMAC_CTL(ch));
                 ioread32(priv->regs + TSI721_OBDMAC_CTL(ch));
 
                 /* Inform upper level to clear all pending tx slots */
-                if (mport->outb_msg[ch].mcback)
-                        mport->outb_msg[ch].mcback(mport,
-                                        priv->omsg_ring[ch].dev_id, ch,
-                                        priv->omsg_ring[ch].tx_slot);
+                dev_id = priv->omsg_ring[ch].dev_id;
+                tx_slot = priv->omsg_ring[ch].tx_slot;
+                do_callback = 1;
+
                 /* Synch tx_slot tracking */
                 iowrite32(priv->omsg_ring[ch].tx_slot,
                         priv->regs + TSI721_OBDMAC_DRDCNT(ch));
@@ -1627,6 +1641,9 @@ no_sts_update:
         }
 
         spin_unlock(&priv->omsg_ring[ch].lock);
+
+        if (mport->outb_msg[ch].mcback && do_callback)
+                mport->outb_msg[ch].mcback(mport, dev_id, ch, tx_slot);
 }
 
 /**
@@ -1768,7 +1785,8 @@ static int tsi721_open_outb_mbox(struct rio_mport *mport, void *dev_id,
         mb();
 
         /* Initialize Outbound Message engine */
-        iowrite32(TSI721_OBDMAC_CTL_INIT, priv->regs + TSI721_OBDMAC_CTL(mbox));
+        iowrite32(TSI721_OBDMAC_CTL_RETRY_THR | TSI721_OBDMAC_CTL_INIT,
+                  priv->regs + TSI721_OBDMAC_CTL(mbox));
         ioread32(priv->regs + TSI721_OBDMAC_DWRCNT(mbox));
         udelay(10);