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>

diff --git a/drivers/rapidio/devices/tsi721.c b/drivers/rapidio/devices/tsi721.c
index 5e1d526..822fd4b 100644 (file)
--- 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);