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ENGR00140702-3 mxc_uart: refine driver for stable Bluetooth

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- Remove tty_buffer_request_room() in mxcuart_readdma_callback()
  tty_insert_flip_string will call tty_buffer_request_room() in
  his loop, but if we call it here, it will return 0, and we
  will lost some read data.

- Remove tasklet when dma_writeback, it's will cause hci lost data
  when write(tx).
  since when this dma callback maybe re-order the next buffer data,
  it will mess up data, make it to a direct call to perpare next
  dma buffer.

Signed-off-by: Zhang Jiejing <jiejing.zhang@freescale.com>
This commit is contained in:
Zhang Jiejing
2011-04-01 10:40:35 +08:00
committed by Matt Sealey
parent 3851242b86
commit 32e18295d1
1 changed files with 24 additions and 39 deletions
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63
drivers/serial/mxc_uart.c
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@@ -1,5 +1,5 @@
/*
* Copyright 2004-2010 Freescale Semiconductor, Inc. All Rights Reserved.
* Copyright 2004-2011 Freescale Semiconductor, Inc. All Rights Reserved.
*/
/*
@@ -84,10 +84,6 @@ typedef struct {
* UART Receive Event ID
*/
int rx_event_id;
/*!
* DMA Transmit tasklet
*/
struct tasklet_struct dma_tx_tasklet;
/*!
* Flag indicates if the channel is in use
*/
@@ -133,14 +129,13 @@ static void mxcuart_stop_tx(struct uart_port *port)
}
/*!
* DMA Transmit tasklet method is scheduled on completion of a DMA transmit
* DMA Transmit method is scheduled on completion of a DMA transmit
* to send out any more data that is available in the UART xmit buffer.
*
* @param arg driver private data
* @param arg pointer of uart_mxc_port
*/
static void dma_tx_do_tasklet(unsigned long arg)
static void mxcuart_dma_tx(uart_mxc_port *umxc)
{
uart_mxc_port *umxc = (uart_mxc_port *) arg;
struct circ_buf *xmit = &umxc->port.info->xmit;
mxc_dma_requestbuf_t writechnl_request;
int tx_num;
@@ -199,16 +194,15 @@ static void mxcuart_dma_writecallback(void *arg, int error, unsigned int count)
dma_unmap_single(umxc->port.dev, umxc->tx_handle, TXDMA_BUFF_SIZE,
DMA_TO_DEVICE);
tx_num = uart_circ_chars_pending(xmit);
/* Schedule a tasklet to send out the pending characters */
if (tx_num > 0) {
tasklet_schedule(&dma_list[umxc->port.line].dma_tx_tasklet);
} else {
if (tx_num > 0)
mxcuart_dma_tx(umxc);
else
dma_list[umxc->port.line].dma_txchnl_inuse = 0;
}
if (tx_num < WAKEUP_CHARS) {
if (tx_num < WAKEUP_CHARS)
uart_write_wakeup(&umxc->port);
}
}
/*!
@@ -231,7 +225,7 @@ static void mxcuart_start_tx(struct uart_port *port)
if (umxc->dma_enabled == 1) {
/*
* If the channel is in use then return immediately and use
* the dma_tx tasklet to transfer queued data when current DMA
* the mxcuart_dma_tx to transfer queued data when current DMA
* transfer is complete
*/
if (dma_list[umxc->port.line].dma_txchnl_inuse == 1) {
@@ -832,7 +826,7 @@ static void mxcuart_dmaread_callback(void *arg, int error, unsigned int cnt)
{
uart_mxc_port *umxc = arg;
struct tty_struct *tty = umxc->port.info->port.tty;
int buff_id, flip_cnt, num_bufs;
int buff_id, num_bufs, rd_cnt;
mxc_dma_requestbuf_t readchnl_request;
mxc_uart_rxdmamap *rx_buf_elem = NULL;
unsigned int sr1, sr2;
@@ -856,18 +850,18 @@ static void mxcuart_dmaread_callback(void *arg, int error, unsigned int cnt)
sr1 = __raw_readl(umxc->port.membase + MXC_UARTUSR1);
sr2 = __raw_readl(umxc->port.membase + MXC_UARTUSR2);
printk(KERN_ERR "UART: DMA_ERROR: sr1:%x sr2:%x\n", sr1, sr2);
if (sr2 & MXC_UARTUSR2_BRCD) {
umxc->port.icount.brk++;
if (uart_handle_break(&umxc->port)) {
if (uart_handle_break(&umxc->port))
goto drop_data;
}
} else if (sr1 & MXC_UARTUSR1_PARITYERR) {
else if (sr1 & MXC_UARTUSR1_PARITYERR)
umxc->port.icount.parity++;
} else if (sr1 & MXC_UARTUSR1_FRAMERR) {
else if (sr1 & MXC_UARTUSR1_FRAMERR)
umxc->port.icount.frame++;
} else if (sr2 & MXC_UARTUSR2_ORE) {
else if (sr2 & MXC_UARTUSR2_ORE)
umxc->port.icount.overrun++;
}
if (umxc->port.read_status_mask & MXC_UARTURXD_BRK) {
@@ -883,26 +877,18 @@ static void mxcuart_dmaread_callback(void *arg, int error, unsigned int cnt)
if (sr2 & MXC_UARTUSR2_ORE)
flag = TTY_OVERRUN;
}
/* By default clearing all error bits in status reg */
/* By default clearing all error bits in status reg */
__raw_writel((MXC_UARTUSR2_BRCD | MXC_UARTUSR2_ORE),
umxc->port.membase + MXC_UARTUSR2);
__raw_writel((MXC_UARTUSR1_PARITYERR | MXC_UARTUSR1_FRAMERR),
umxc->port.membase + MXC_UARTUSR1);
}
flip_cnt = tty_buffer_request_room(tty, cnt);
rd_cnt = tty_insert_flip_string(tty, rx_buf_elem->rx_buf, cnt);
umxc->port.icount.rx += rd_cnt;
/* Check for space availability in the TTY Flip buffer */
if (flip_cnt <= 0) {
goto drop_data;
}
umxc->port.icount.rx += flip_cnt;
tty_insert_flip_string(tty, rx_buf_elem->rx_buf, flip_cnt);
if (flag != TTY_NORMAL) {
if (flag != TTY_NORMAL)
tty_insert_flip_char(tty, 0, flag);
}
tty_flip_buffer_push(tty);
umxc->port.info->port.tty->real_raw = 1;
@@ -929,9 +915,10 @@ static void mxcuart_dmaread_callback(void *arg, int error, unsigned int cnt)
*/
static int mxcuart_initdma(dma_info * d_info, uart_mxc_port * umxc)
{
int ret = 0, rxbufs, i, j;
int rxbufs, i, j;
mxc_dma_requestbuf_t *readchnl_reqelem;
mxc_uart_rxdmamap *rx_buf_elem;
int ret = 0;
/* Request for the read and write channels */
d_info->rd_channel = mxc_dma_request(umxc->dma_rx_id, "MXC UART Read");
@@ -1006,8 +993,6 @@ static int mxcuart_initdma(dma_info * d_info, uart_mxc_port * umxc)
/* Start the read channel */
mxc_dma_enable(d_info->rd_channel);
kfree(readchnl_reqelem);
tasklet_init(&d_info->dma_tx_tasklet, dma_tx_do_tasklet,
(unsigned long)umxc);
d_info->dma_txchnl_inuse = 0;
return ret;
cleanup: