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path: root/drivers/char/synclink_gt.c
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Diffstat (limited to 'drivers/char/synclink_gt.c')
-rw-r--r--drivers/char/synclink_gt.c72
1 files changed, 30 insertions, 42 deletions
diff --git a/drivers/char/synclink_gt.c b/drivers/char/synclink_gt.c
index 1386625fc4c..a2e67e6df3a 100644
--- a/drivers/char/synclink_gt.c
+++ b/drivers/char/synclink_gt.c
@@ -467,7 +467,6 @@ static unsigned int free_tbuf_count(struct slgt_info *info);
static unsigned int tbuf_bytes(struct slgt_info *info);
static void reset_tbufs(struct slgt_info *info);
static void tdma_reset(struct slgt_info *info);
-static void tdma_start(struct slgt_info *info);
static void tx_load(struct slgt_info *info, const char *buf, unsigned int count);
static void get_signals(struct slgt_info *info);
@@ -795,6 +794,18 @@ static void set_termios(struct tty_struct *tty, struct ktermios *old_termios)
}
}
+static void update_tx_timer(struct slgt_info *info)
+{
+ /*
+ * use worst case speed of 1200bps to calculate transmit timeout
+ * based on data in buffers (tbuf_bytes) and FIFO (128 bytes)
+ */
+ if (info->params.mode == MGSL_MODE_HDLC) {
+ int timeout = (tbuf_bytes(info) * 7) + 1000;
+ mod_timer(&info->tx_timer, jiffies + msecs_to_jiffies(timeout));
+ }
+}
+
static int write(struct tty_struct *tty,
const unsigned char *buf, int count)
{
@@ -838,8 +849,18 @@ start:
spin_lock_irqsave(&info->lock,flags);
if (!info->tx_active)
tx_start(info);
- else
- tdma_start(info);
+ else if (!(rd_reg32(info, TDCSR) & BIT0)) {
+ /* transmit still active but transmit DMA stopped */
+ unsigned int i = info->tbuf_current;
+ if (!i)
+ i = info->tbuf_count;
+ i--;
+ /* if DMA buf unsent must try later after tx idle */
+ if (desc_count(info->tbufs[i]))
+ ret = 0;
+ }
+ if (ret > 0)
+ update_tx_timer(info);
spin_unlock_irqrestore(&info->lock,flags);
}
@@ -1502,10 +1523,9 @@ static int hdlcdev_xmit(struct sk_buff *skb, struct net_device *dev)
/* save start time for transmit timeout detection */
dev->trans_start = jiffies;
- /* start hardware transmitter if necessary */
spin_lock_irqsave(&info->lock,flags);
- if (!info->tx_active)
- tx_start(info);
+ tx_start(info);
+ update_tx_timer(info);
spin_unlock_irqrestore(&info->lock,flags);
return 0;
@@ -3946,50 +3966,19 @@ static void tx_start(struct slgt_info *info)
slgt_irq_on(info, IRQ_TXUNDER + IRQ_TXIDLE);
/* clear tx idle and underrun status bits */
wr_reg16(info, SSR, (unsigned short)(IRQ_TXIDLE + IRQ_TXUNDER));
- if (info->params.mode == MGSL_MODE_HDLC)
- mod_timer(&info->tx_timer, jiffies +
- msecs_to_jiffies(5000));
} else {
slgt_irq_off(info, IRQ_TXDATA);
slgt_irq_on(info, IRQ_TXIDLE);
/* clear tx idle status bit */
wr_reg16(info, SSR, IRQ_TXIDLE);
}
- tdma_start(info);
+ /* set 1st descriptor address and start DMA */
+ wr_reg32(info, TDDAR, info->tbufs[info->tbuf_start].pdesc);
+ wr_reg32(info, TDCSR, BIT2 + BIT0);
info->tx_active = true;
}
}
-/*
- * start transmit DMA if inactive and there are unsent buffers
- */
-static void tdma_start(struct slgt_info *info)
-{
- unsigned int i;
-
- if (rd_reg32(info, TDCSR) & BIT0)
- return;
-
- /* transmit DMA inactive, check for unsent buffers */
- i = info->tbuf_start;
- while (!desc_count(info->tbufs[i])) {
- if (++i == info->tbuf_count)
- i = 0;
- if (i == info->tbuf_current)
- return;
- }
- info->tbuf_start = i;
-
- /* there are unsent buffers, start transmit DMA */
-
- /* reset needed if previous error condition */
- tdma_reset(info);
-
- /* set 1st descriptor address */
- wr_reg32(info, TDDAR, info->tbufs[info->tbuf_start].pdesc);
- wr_reg32(info, TDCSR, BIT2 + BIT0); /* IRQ + DMA enable */
-}
-
static void tx_stop(struct slgt_info *info)
{
unsigned short val;
@@ -5004,8 +4993,7 @@ static void tx_timeout(unsigned long context)
info->icount.txtimeout++;
}
spin_lock_irqsave(&info->lock,flags);
- info->tx_active = false;
- info->tx_count = 0;
+ tx_stop(info);
spin_unlock_irqrestore(&info->lock,flags);
#if SYNCLINK_GENERIC_HDLC