高通平臺串列埠除錯 AP與模組串列埠通訊除錯總結 uart
高通平臺串列埠除錯 AP與模組串列埠通訊除錯總結
2016年07月07日 18:03:41
閱讀數:3144
原文網址:http://blog.csdn.net/linux_devices_driver/article/details/24329043
1:檢查AP端串列埠配置是否ok:
a:高通平臺檢視DMA傳輸:
echo 1 > /sys/kernel/debug/msm_serial_hsl/loopback.0 //打開回環開關
adb shell cat /dev/ttyHSL1
另起視窗
# adb shell
# echo 11111111 > /dev/ttyHSL1
若DMA通道ok,控制檯會迴圈顯示;
b:檢視uart gpio是否ok:
tx高電平、rfr為低電平,rx,cts為輸入;
如果tx為低電平,那麼gpio肯定沒有配置好,再次檢查gpio配置問題;
如果以上2步都ok,那麼UART應該ok了,再次檢查:
adb shell cat /dev/ttyHSL1
將TX與RX短接;
另起視窗
# adb shell
# echo 11111111 > /dev/ttyHSL1
迴圈顯示那麼恭喜UART功能配置好了。
2:Termios引數配置:
影響通訊資料格式的關鍵
幾個引數:
1:波特率-speed,通常
115200,最高4M;
2:奇偶校驗-Parity,通
常為None;
3:資料位-Data,通常
8bit;
4:停止位-Stopbits,通
常1bit;
一般情況下預設為115200 8N1,也就是波特率115200,8bit資料位,無奇偶校驗,1bit停止位。
為了使得AP可以與模組串列埠通訊,必須先了解模組的termios設定。
Ap端termios設定:
首先應用開啟串列埠時會設定termios:
- termios.c_cflag &= ~CSIZE;
- termios.c_cflag |= CS8;
- termios.c_cflag &= ~CSTOPB;
- termios.c_cflag &= ~PARENB;
- termios.c_cflag &= ~CBAUD;
- termios.c_cflag |= B3000000;
- termios.c_cflag |= CREAD | CLOCAL;
- termios.c_cflag |= CRTSCTS; /* turn on hardware flow control */
- termios.c_iflag &= ~(IXOFF | IXON | IXANY); /* soft flow control */
驅動介面會根據termios引數來設定底層串列埠:
以8064 msm_seriel_hs.c為例說明:
uart介面封裝:
- static struct uart_ops msm_hs_ops = {
- .tx_empty = msm_hs_tx_empty,
- .set_mctrl = msm_hs_set_mctrl_locked,
- .get_mctrl = msm_hs_get_mctrl_locked,
- .stop_tx = msm_hs_stop_tx_locked,
- .start_tx = msm_hs_start_tx_locked,
- .stop_rx = msm_hs_stop_rx_locked,
- .enable_ms = msm_hs_enable_ms_locked,
- .break_ctl = msm_hs_break_ctl,
- .startup = msm_hs_startup,
- .shutdown = msm_hs_shutdown,
- .set_termios = msm_hs_set_termios,
- .type = msm_hs_type,
- .config_port = msm_hs_config_port,
- .release_port = msm_hs_release_port,
- .request_port = msm_hs_request_port,
- .flush_buffer = msm_hs_flush_buffer_locked,
- };
下面是底層設定函式,上層開啟串列埠,引數未固定的話驅動走的是8N1,底層除錯只使用echo或者cat /dev/ttyHSL0時
波特率一律是9600,模組不是9600時那麼通訊肯定會失敗,所以AP需要根據模組重新設定。
波特率。
//設定termios介面
- /*
- * termios : new ktermios
- * oldtermios: old ktermios previous setting
- *
- * Configure the serial port
- */
- static void msm_hs_set_termios(struct uart_port *uport,
- struct ktermios *termios,
- struct ktermios *oldtermios)
- {
- unsigned int bps;
- unsigned long data;
- unsigned long flags;
- int ret;
- unsigned int c_cflag = termios->c_cflag;
- struct msm_hs_port *msm_uport = UARTDM_TO_MSM(uport);
- mutex_lock(&msm_uport->clk_mutex);
- spin_lock_irqsave(&uport->lock, flags);
- /*
- * Disable Rx channel of UARTDM
- * DMA Rx Stall happens if enqueue and flush of Rx command happens
- * concurrently. Hence before changing the baud rate/protocol
- * configuration and sending flush command to ADM, disable the Rx
- * channel of UARTDM.
- * Note: should not reset the receiver here immediately as it is not
- * suggested to do disable/reset or reset/disable at the same time.
- */
- data = msm_hs_read(uport, UARTDM_DMEN_ADDR);
- data &= ~UARTDM_RX_DM_EN_BMSK;
- msm_hs_write(uport, UARTDM_DMEN_ADDR, data);
- /* 300 is the minimum baud support by the driver */
- bps = uart_get_baud_rate(uport, termios, oldtermios, 200, 4000000);
- /* Temporary remapping 200 BAUD to 3.2 mbps */
- if (bps == 200)
- bps = 3200000;
- uport->uartclk = clk_get_rate(msm_uport->clk);
- if (!uport->uartclk)
- msm_hs_set_std_bps_locked(uport, bps);
- else
- flags = msm_hs_set_bps_locked(uport, bps, flags);//函式裡面設定baud;
- data = msm_hs_read(uport, UARTDM_MR2_ADDR);
- data &= ~UARTDM_MR2_PARITY_MODE_BMSK;
- /* set parity */ //設定奇偶校驗
- if (PARENB == (c_cflag & PARENB)) {
- if (PARODD == (c_cflag & PARODD)) {
- data |= ODD_PARITY;
- } else if (CMSPAR == (c_cflag & CMSPAR)) {
- data |= SPACE_PARITY;
- } else {
- data |= EVEN_PARITY;
- }
- }
- /* Set bits per char */ //設定資料位
- data &= ~UARTDM_MR2_BITS_PER_CHAR_BMSK;
- switch (c_cflag & CSIZE) {
- case CS5:
- data |= FIVE_BPC;
- break;
- case CS6:
- data |= SIX_BPC;
- break;
- case CS7:
- data |= SEVEN_BPC;
- break;
- default:
- data |= EIGHT_BPC;
- break;
- }
- /* stop bits */ //設定停止位
- if (c_cflag & CSTOPB) {
- data |= STOP_BIT_TWO;
- } else {
- /* otherwise 1 stop bit */
- data |= STOP_BIT_ONE;
- }
- data |= UARTDM_MR2_ERROR_MODE_BMSK;
- /* write parity/bits per char/stop bit configuration */
- msm_hs_write(uport, UARTDM_MR2_ADDR, data);
- /* Configure HW flow control */ //設定是否使用硬體流控
- data = msm_hs_read(uport, UARTDM_MR1_ADDR);
- data &= ~(UARTDM_MR1_CTS_CTL_BMSK |
- UARTDM_MR1_RX_RDY_CTL_BMSK);
- if (c_cflag & CRTSCTS) {
- data |= UARTDM_MR1_CTS_CTL_BMSK;
- data |= UARTDM_MR1_RX_RDY_CTL_BMSK;
- }
- msm_hs_write(uport, UARTDM_MR1_ADDR, data);
- uport->ignore_status_mask = termios->c_iflag & INPCK;
- uport->ignore_status_mask |= termios->c_iflag & IGNPAR;
- uport->ignore_status_mask |= termios->c_iflag & IGNBRK;
- uport->read_status_mask = (termios->c_cflag & CREAD);
- msm_hs_write(uport, UARTDM_IMR_ADDR, 0);
- /* Set Transmit software time out */
- uart_update_timeout(uport, c_cflag, bps);
- msm_hs_write(uport, UARTDM_CR_ADDR, RESET_RX);
- msm_hs_write(uport, UARTDM_CR_ADDR, RESET_TX);
- if (msm_uport->rx.flush == FLUSH_NONE) {
- wake_lock(&msm_uport->rx.wake_lock);
- msm_uport->rx.flush = FLUSH_IGNORE;
- /*
- * Before using dmov APIs make sure that
- * previous writel are completed. Hence
- * dsb requires here.
- */
- mb();
- msm_uport->rx_discard_flush_issued = true;
- /* do discard flush */
- msm_dmov_flush(msm_uport->dma_rx_channel, 0);
- spin_unlock_irqrestore(&uport->lock, flags);
- pr_debug("%s(): wainting for flush completion.\n",
- __func__);
- ret = wait_event_timeout(msm_uport->rx.wait,
- msm_uport->rx_discard_flush_issued == false,
- RX_FLUSH_COMPLETE_TIMEOUT);
- if (!ret)
- pr_err("%s(): Discard flush completion pending.\n",
- __func__);
- spin_lock_irqsave(&uport->lock, flags);
- }
- msm_hs_write(uport, UARTDM_IMR_ADDR, msm_uport->imr_reg);
- mb();
- spin_unlock_irqrestore(&uport->lock, flags);
- mutex_unlock(&msm_uport->clk_mutex);
- }
3:串列埠通訊問題總結:
遇見過模組不能響應AP的問題:
1:硬體流控問題,若模組使用了硬體流控,配置rfr與cts,使得模組認為
AP準備好了,可以傳送資料了。
2:AP端波特率沒有與模組匹配上,要是懷疑AP波特率設定是否ok,可以將串列埠線連線TX,
設定termios 波特率來看輸出是否ok,這種方法還可以測試驗證AP端各個波特率是否OK,我使用的
minicon可以驗證到460800