diff options
-rw-r--r-- | drivers/char/synclink_gt.c | 59 |
1 files changed, 57 insertions, 2 deletions
diff --git a/drivers/char/synclink_gt.c b/drivers/char/synclink_gt.c index 3cfc9e1f8882..8511e2e43c18 100644 --- a/drivers/char/synclink_gt.c +++ b/drivers/char/synclink_gt.c @@ -214,6 +214,7 @@ struct slgt_desc char *buf; /* virtual address of data buffer */ unsigned int pdesc; /* physical address of this descriptor */ dma_addr_t buf_dma_addr; + unsigned short buf_count; }; #define set_desc_buffer(a,b) (a).pbuf = cpu_to_le32((unsigned int)(b)) @@ -466,6 +467,7 @@ static void tx_start(struct slgt_info *info); static void tx_stop(struct slgt_info *info); static void tx_set_idle(struct slgt_info *info); 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); @@ -1388,10 +1390,12 @@ done: static int chars_in_buffer(struct tty_struct *tty) { struct slgt_info *info = tty->driver_data; + int count; if (sanity_check(info, tty->name, "chars_in_buffer")) return 0; - DBGINFO(("%s chars_in_buffer()=%d\n", info->device_name, info->tx_count)); - return info->tx_count; + count = tbuf_bytes(info); + DBGINFO(("%s chars_in_buffer()=%d\n", info->device_name, count)); + return count; } /* @@ -4671,6 +4675,56 @@ static unsigned int free_tbuf_count(struct slgt_info *info) } /* + * return number of bytes in unsent transmit DMA buffers + * and the serial controller tx FIFO + */ +static unsigned int tbuf_bytes(struct slgt_info *info) +{ + unsigned int total_count = 0; + unsigned int i = info->tbuf_current; + unsigned int reg_value; + unsigned int count; + unsigned int active_buf_count = 0; + + /* + * Add descriptor counts for all tx DMA buffers. + * If count is zero (cleared by DMA controller after read), + * the buffer is complete or is actively being read from. + * + * Record buf_count of last buffer with zero count starting + * from current ring position. buf_count is mirror + * copy of count and is not cleared by serial controller. + * If DMA controller is active, that buffer is actively + * being read so add to total. + */ + do { + count = desc_count(info->tbufs[i]); + if (count) + total_count += count; + else if (!total_count) + active_buf_count = info->tbufs[i].buf_count; + if (++i == info->tbuf_count) + i = 0; + } while (i != info->tbuf_current); + + /* read tx DMA status register */ + reg_value = rd_reg32(info, TDCSR); + + /* if tx DMA active, last zero count buffer is in use */ + if (reg_value & BIT0) + total_count += active_buf_count; + + /* add tx FIFO count = reg_value[15..8] */ + total_count += (reg_value >> 8) & 0xff; + + /* if transmitter active add one byte for shift register */ + if (info->tx_active) + total_count++; + + return total_count; +} + +/* * load transmit DMA buffer(s) with data */ static void tx_load(struct slgt_info *info, const char *buf, unsigned int size) @@ -4708,6 +4762,7 @@ static void tx_load(struct slgt_info *info, const char *buf, unsigned int size) set_desc_eof(*d, 0); set_desc_count(*d, count); + d->buf_count = count; } info->tbuf_current = i; |