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author | David S. Miller <davem@davemloft.net> | 2010-03-15 23:23:54 (GMT) |
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committer | David S. Miller <davem@davemloft.net> | 2010-03-15 23:23:54 (GMT) |
commit | 4961e02f1999e1c3468c09b2669c94d7c3ae82a8 (patch) | |
tree | 44c15abb09d7ba5e17a9aba95ee246648b1c1a8a /drivers/char/synclink_gt.c | |
parent | d14a0ebda7d3daede1a99c01527affb9ceaa4c22 (diff) | |
parent | a3d3203e4bb40f253b1541e310dc0f9305be7c84 (diff) | |
download | linux-fsl-qoriq-4961e02f1999e1c3468c09b2669c94d7c3ae82a8.tar.xz |
Merge branch 'master' of /home/davem/src/GIT/linux-2.6/
Diffstat (limited to 'drivers/char/synclink_gt.c')
-rw-r--r-- | drivers/char/synclink_gt.c | 186 |
1 files changed, 105 insertions, 81 deletions
diff --git a/drivers/char/synclink_gt.c b/drivers/char/synclink_gt.c index 8678f0c..4561ce2 100644 --- a/drivers/char/synclink_gt.c +++ b/drivers/char/synclink_gt.c @@ -468,7 +468,7 @@ 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 tx_load(struct slgt_info *info, const char *buf, unsigned int count); +static bool tx_load(struct slgt_info *info, const char *buf, unsigned int count); static void get_signals(struct slgt_info *info); static void set_signals(struct slgt_info *info); @@ -813,59 +813,32 @@ static int write(struct tty_struct *tty, int ret = 0; struct slgt_info *info = tty->driver_data; unsigned long flags; - unsigned int bufs_needed; if (sanity_check(info, tty->name, "write")) - goto cleanup; + return -EIO; + DBGINFO(("%s write count=%d\n", info->device_name, count)); - if (!info->tx_buf) - goto cleanup; + if (!info->tx_buf || (count > info->max_frame_size)) + return -EIO; - if (count > info->max_frame_size) { - ret = -EIO; - goto cleanup; - } + if (!count || tty->stopped || tty->hw_stopped) + return 0; - if (!count) - goto cleanup; + spin_lock_irqsave(&info->lock, flags); - if (!info->tx_active && info->tx_count) { + if (info->tx_count) { /* send accumulated data from send_char() */ - tx_load(info, info->tx_buf, info->tx_count); - goto start; + if (!tx_load(info, info->tx_buf, info->tx_count)) + goto cleanup; + info->tx_count = 0; } - bufs_needed = (count/DMABUFSIZE); - if (count % DMABUFSIZE) - ++bufs_needed; - if (bufs_needed > free_tbuf_count(info)) - goto cleanup; - ret = info->tx_count = count; - tx_load(info, buf, count); - goto start; - -start: - if (info->tx_count && !tty->stopped && !tty->hw_stopped) { - spin_lock_irqsave(&info->lock,flags); - if (!info->tx_active) - tx_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); - } + if (tx_load(info, buf, count)) + ret = count; cleanup: + spin_unlock_irqrestore(&info->lock, flags); DBGINFO(("%s write rc=%d\n", info->device_name, ret)); return ret; } @@ -882,7 +855,7 @@ static int put_char(struct tty_struct *tty, unsigned char ch) if (!info->tx_buf) return 0; spin_lock_irqsave(&info->lock,flags); - if (!info->tx_active && (info->tx_count < info->max_frame_size)) { + if (info->tx_count < info->max_frame_size) { info->tx_buf[info->tx_count++] = ch; ret = 1; } @@ -981,10 +954,8 @@ static void flush_chars(struct tty_struct *tty) DBGINFO(("%s flush_chars start transmit\n", info->device_name)); spin_lock_irqsave(&info->lock,flags); - if (!info->tx_active && info->tx_count) { - tx_load(info, info->tx_buf,info->tx_count); - tx_start(info); - } + if (info->tx_count && tx_load(info, info->tx_buf, info->tx_count)) + info->tx_count = 0; spin_unlock_irqrestore(&info->lock,flags); } @@ -997,10 +968,9 @@ static void flush_buffer(struct tty_struct *tty) return; DBGINFO(("%s flush_buffer\n", info->device_name)); - spin_lock_irqsave(&info->lock,flags); - if (!info->tx_active) - info->tx_count = 0; - spin_unlock_irqrestore(&info->lock,flags); + spin_lock_irqsave(&info->lock, flags); + info->tx_count = 0; + spin_unlock_irqrestore(&info->lock, flags); tty_wakeup(tty); } @@ -1033,12 +1003,10 @@ static void tx_release(struct tty_struct *tty) if (sanity_check(info, tty->name, "tx_release")) return; DBGINFO(("%s tx_release\n", info->device_name)); - spin_lock_irqsave(&info->lock,flags); - if (!info->tx_active && info->tx_count) { - tx_load(info, info->tx_buf, info->tx_count); - tx_start(info); - } - spin_unlock_irqrestore(&info->lock,flags); + spin_lock_irqsave(&info->lock, flags); + if (info->tx_count && tx_load(info, info->tx_buf, info->tx_count)) + info->tx_count = 0; + spin_unlock_irqrestore(&info->lock, flags); } /* @@ -1506,27 +1474,25 @@ static netdev_tx_t hdlcdev_xmit(struct sk_buff *skb, DBGINFO(("%s hdlc_xmit\n", dev->name)); + if (!skb->len) + return NETDEV_TX_OK; + /* stop sending until this frame completes */ netif_stop_queue(dev); - /* copy data to device buffers */ - info->tx_count = skb->len; - tx_load(info, skb->data, skb->len); - /* update network statistics */ dev->stats.tx_packets++; dev->stats.tx_bytes += skb->len; - /* done with socket buffer, so free it */ - dev_kfree_skb(skb); - /* save start time for transmit timeout detection */ dev->trans_start = jiffies; - spin_lock_irqsave(&info->lock,flags); - tx_start(info); - update_tx_timer(info); - spin_unlock_irqrestore(&info->lock,flags); + spin_lock_irqsave(&info->lock, flags); + tx_load(info, skb->data, skb->len); + spin_unlock_irqrestore(&info->lock, flags); + + /* done with socket buffer, so free it */ + dev_kfree_skb(skb); return NETDEV_TX_OK; } @@ -2180,7 +2146,7 @@ static void isr_serial(struct slgt_info *info) if (info->params.mode == MGSL_MODE_ASYNC) { if (status & IRQ_TXIDLE) { - if (info->tx_count) + if (info->tx_active) isr_txeom(info, status); } if (info->rx_pio && (status & IRQ_RXDATA)) @@ -2276,13 +2242,42 @@ static void isr_tdma(struct slgt_info *info) } } +/* + * return true if there are unsent tx DMA buffers, otherwise false + * + * if there are unsent buffers then info->tbuf_start + * is set to index of first unsent buffer + */ +static bool unsent_tbufs(struct slgt_info *info) +{ + unsigned int i = info->tbuf_current; + bool rc = false; + + /* + * search backwards from last loaded buffer (precedes tbuf_current) + * for first unsent buffer (desc_count > 0) + */ + + do { + if (i) + i--; + else + i = info->tbuf_count - 1; + if (!desc_count(info->tbufs[i])) + break; + info->tbuf_start = i; + rc = true; + } while (i != info->tbuf_current); + + return rc; +} + static void isr_txeom(struct slgt_info *info, unsigned short status) { DBGISR(("%s txeom status=%04x\n", info->device_name, status)); slgt_irq_off(info, IRQ_TXDATA + IRQ_TXIDLE + IRQ_TXUNDER); tdma_reset(info); - reset_tbufs(info); if (status & IRQ_TXUNDER) { unsigned short val = rd_reg16(info, TCR); wr_reg16(info, TCR, (unsigned short)(val | BIT2)); /* set reset bit */ @@ -2297,8 +2292,12 @@ static void isr_txeom(struct slgt_info *info, unsigned short status) info->icount.txok++; } + if (unsent_tbufs(info)) { + tx_start(info); + update_tx_timer(info); + return; + } info->tx_active = false; - info->tx_count = 0; del_timer(&info->tx_timer); @@ -3949,7 +3948,7 @@ static void tx_start(struct slgt_info *info) info->tx_enabled = true; } - if (info->tx_count) { + if (desc_count(info->tbufs[info->tbuf_start])) { info->drop_rts_on_tx_done = false; if (info->params.mode != MGSL_MODE_ASYNC) { @@ -4772,25 +4771,36 @@ static unsigned int tbuf_bytes(struct slgt_info *info) } /* - * load transmit DMA buffer(s) with data + * load data into transmit DMA buffer ring and start transmitter if needed + * return true if data accepted, otherwise false (buffers full) */ -static void tx_load(struct slgt_info *info, const char *buf, unsigned int size) +static bool tx_load(struct slgt_info *info, const char *buf, unsigned int size) { unsigned short count; unsigned int i; struct slgt_desc *d; - if (size == 0) - return; + /* check required buffer space */ + if (DIV_ROUND_UP(size, DMABUFSIZE) > free_tbuf_count(info)) + return false; DBGDATA(info, buf, size, "tx"); + /* + * copy data to one or more DMA buffers in circular ring + * tbuf_start = first buffer for this data + * tbuf_current = next free buffer + * + * Copy all data before making data visible to DMA controller by + * setting descriptor count of the first buffer. + * This prevents an active DMA controller from reading the first DMA + * buffers of a frame and stopping before the final buffers are filled. + */ + info->tbuf_start = i = info->tbuf_current; while (size) { d = &info->tbufs[i]; - if (++i == info->tbuf_count) - i = 0; count = (unsigned short)((size > DMABUFSIZE) ? DMABUFSIZE : size); memcpy(d->buf, buf, count); @@ -4808,11 +4818,27 @@ static void tx_load(struct slgt_info *info, const char *buf, unsigned int size) else set_desc_eof(*d, 0); - set_desc_count(*d, count); + /* set descriptor count for all but first buffer */ + if (i != info->tbuf_start) + set_desc_count(*d, count); d->buf_count = count; + + if (++i == info->tbuf_count) + i = 0; } info->tbuf_current = i; + + /* set first buffer count to make new data visible to DMA controller */ + d = &info->tbufs[info->tbuf_start]; + set_desc_count(*d, d->buf_count); + + /* start transmitter if needed and update transmit timeout */ + if (!info->tx_active) + tx_start(info); + update_tx_timer(info); + + return true; } static int register_test(struct slgt_info *info) @@ -4934,9 +4960,7 @@ static int loopback_test(struct slgt_info *info) spin_lock_irqsave(&info->lock,flags); async_mode(info); rx_start(info); - info->tx_count = count; tx_load(info, buf, count); - tx_start(info); spin_unlock_irqrestore(&info->lock, flags); /* wait for receive complete */ |