solos: Tidy up tx_mask handling for ports which need TX

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 13 insertions, 7 deletions

diff --git a/drivers/atm/solos-pci.c b/drivers/atm/solos-pci.c
index acba08df5eb0..bf59c407fec9 100644
--- a/drivers/atm/solos-pci.c
+++ b/drivers/atm/solos-pci.c
@@ -100,6 +100,7 @@ struct solos_card {
         void __iomem *config_regs;
         void __iomem *buffers;
         int nr_ports;
+        int tx_mask;
         struct pci_dev *dev;
         struct atm_dev *atmdev[4];
         struct tasklet_struct tlet;
@@ -590,15 +591,13 @@ void solos_bh(unsigned long card_arg)
         struct solos_card *card = (void *)card_arg;
         int port;
         uint32_t card_flags;
-        uint32_t tx_mask;
         uint32_t rx_done = 0;
 
         card_flags = ioread32(card->config_regs + FLAGS_ADDR);
 
         /* The TX bits are set if the channel is busy; clear if not. We want to
            invoke fpga_tx() unless _all_ the bits for active channels are set */
-        tx_mask = (1 << card->nr_ports) - 1;
-        if ((card_flags & tx_mask) != tx_mask)
+        if ((card_flags & card->tx_mask) != card->tx_mask)
                 fpga_tx(card);
 
         for (port = 0; port < card->nr_ports; port++) {
@@ -887,15 +886,20 @@ static void fpga_queue(struct solos_card *card, int port, struct sk_buff *skb,
                        struct atm_vcc *vcc)
 {
         int old_len;
+        unsigned long flags;
 
         SKB_CB(skb)->vcc = vcc;
 
-        spin_lock(&card->tx_queue_lock);
+        spin_lock_irqsave(&card->tx_queue_lock, flags);
         old_len = skb_queue_len(&card->tx_queue[port]);
         skb_queue_tail(&card->tx_queue[port], skb);
-        spin_unlock(&card->tx_queue_lock);
+        if (!old_len) {
+                card->tx_mask |= (1 << port);
+        }
+        spin_unlock_irqrestore(&card->tx_queue_lock, flags);
 
-        /* If TX might need to be started, do so */
+        /* Theoretically we could just schedule the tasklet here, but
+           that introduces latency we don't want -- it's noticeable */
         if (!old_len)
                 fpga_tx(card);
 }
@@ -911,7 +915,7 @@ static int fpga_tx(struct solos_card *card)
 
         spin_lock_irqsave(&card->tx_lock, flags);
 
-        tx_pending = ioread32(card->config_regs + FLAGS_ADDR);
+        tx_pending = ioread32(card->config_regs + FLAGS_ADDR) & card->tx_mask;
 
         dev_vdbg(&card->dev->dev, "TX Flags are %X\n", tx_pending);
 
@@ -925,6 +929,8 @@ static int fpga_tx(struct solos_card *card)
                         
                         spin_lock(&card->tx_queue_lock);
                         skb = skb_dequeue(&card->tx_queue[port]);
+                        if (!skb)
+                                card->tx_mask &= ~(1 << port);
                         spin_unlock(&card->tx_queue_lock);
 
                         if (skb && !card->using_dma) {