How to disable CSI0 to enable UART4 and UART5 in IMX53_SMD

[winstonrodrigue]

Dear Friends,

        I am working on imx53 sabre tablet (imx53_smd) board. So far I am successfull in testing most of the peripherals.

Now i am stuck at a point where I cannot test UART4 and UART5. remaining UARTS are working fine.

I suspect from following reasons..

     1. May be UART pads are not defined properly.

         but I have added UART4 and UART5 pad definitions in iomux_v3_cfg_t mx53_smd_pads[] of mx53_smd.c

        these ones :

        MX53_PAD_CSI0_DAT12__UART4_TXD_MUX,

        MX53_PAD_CSI0_DAT13__UART4_RXD_MUX,

        MX53_PAD_CSI0_DAT14__UART5_TXD_MUX,

        MX53_PAD_CSI0_DAT15__UART5_RXD_MUX,

       even I have changed to iomux-mx53.h file as per the latest freescale kernel tree. for al the UARTS.

  2. May be CSI0 interface is not allowing the UARTS to be used.

     the connector on board has a 120 pin QTH connectorin which there are signals for auxillary display and camera

     interfaces (CSI0). On the Same CSI0 interface you will find UART4 and UART5 signals. And I definitely dont need CSI interface.

so my guess is since CSI0 interface is still enabled so i cannot access the UART4 and UART5 signals.

So is there any way to disable the CSI0 interface. ?

Regards,

   Winston

[winstonrodrigue]

And I tried to make UART4 tx/rx as gpios... as follows in mx53_smd.c file

        MX53_PAD_CSI0_DAT12__GPIO5_30,     number is 158

        MX53_PAD_CSI0_DAT13__GPIO5_31,       and 159

when I try to use them as GPIO like below .....

   cd /sys/class/gpio

   echo 158 > export

   cd gpio158

   echo out > direction

   echo 1 > val

   echo 0 > val

And when I see the output in oscilloscope signal doesnt change at all.... for both pins..

Why I cannot use these pins neither as UART nor as GPIOs....?

Regards,

   Winston

[yektaayduk]

I'm also struggling with uarts.

Maybe also clocks for uart4 and 5 should be registered ,because clock.c file has only registration for these uart 1-2-3.

linux-2.6.35.3/arch/arm/mach-mx5/clock.c

    _REGISTER_CLOCK("mxcintuart.0", NULL, uart1_clk[0]),

    _REGISTER_CLOCK("mxcintuart.1", NULL, uart2_clk[0]),

    _REGISTER_CLOCK("mxcintuart.2", NULL, uart3_clk[0]),

[winstonrodrigue]

If you are using smd board and BSP 11.09 clocks are enabled for all the UARTS....

static struct clk_lookup mx53_lookups[] = {

        _REGISTER_CLOCK(NULL, "pll4", pll4_sw_clk),

        _REGISTER_CLOCK("mxcintuart.3", NULL, uart4_clk[0]),

        _REGISTER_CLOCK("mxcintuart.4", NULL, uart5_clk[0]),

[yektaayduk]

Any progress ?

[winstonrodrigue]

Hey yekthaayduk.....

              There is npo progres on this... because I cannot access the UART4 and UART5 on SABRE board coz the pins are on camera sensopr connector that is J12. I could solder it but I m scared that I may damage the sensor connector pins. In my custom board I m going to remove the Camera So i will be using UART4 and UART5 later....

  Regards,

    Winston

[AlanZhang]

First, modify the following points inside mx53_smd.c file:

1. Inside static iomux_v3_cfg_t mx53_smd_pads[]

    Remove :

/* CSI0 */

    MX53_PAD_CSI0_DAT12__IPU_CSI0_D_12,

    MX53_PAD_CSI0_DAT13__IPU_CSI0_D_13,

    MX53_PAD_CSI0_DAT14__IPU_CSI0_D_14,

    MX53_PAD_CSI0_DAT15__IPU_CSI0_D_15,

    MX53_PAD_CSI0_DAT16__IPU_CSI0_D_16,

    MX53_PAD_CSI0_DAT17__IPU_CSI0_D_17,

    MX53_PAD_CSI0_DAT18__IPU_CSI0_D_18,

    MX53_PAD_CSI0_DAT19__IPU_CSI0_D_19,

    MX53_PAD_CSI0_VSYNC__IPU_CSI0_VSYNC,

    MX53_PAD_CSI0_MCLK__IPU_CSI0_HSYNC,

    MX53_PAD_CSI0_PIXCLK__IPU_CSI0_PIXCLK,

    Replace w/ :

    MX53_PAD_CSI0_DAT12__UART4_TXD_MUX

    MX53_PAD_CSI0_DAT13__UART4_RXD_MUX

    MX53_PAD_CSI0_DAT16__UART4_RTS

    MX53_PAD_CSI0_DAT17__UART4_CTS

    MX53_PAD_CSI0_DAT14__UART5_TXD_MUX

    MX53_PAD_CSI0_DAT15__UART5_RXD_MUX

    MX53_PAD_CSI0_DAT18__UART5_RTS

    MX53_PAD_CSI0_DAT19__UART5_CTS

2. Remove "ov5642" in  mxc_i2c0_board_info[];

3. Remove the following statements:

/* Camera reset */

    gpio_request(MX53_SMD_CSI0_RST, "cam-reset");

    gpio_direction_output(MX53_SMD_CSI0_RST, 1);

    /* Camera power down */

    gpio_request(MX53_SMD_CSI0_PWN, "cam-pwdn");

    gpio_direction_output(MX53_SMD_CSI0_PWN, 1);

    msleep(1);

    gpio_set_value(MX53_SMD_CSI0_PWN, 0);

Then, build the uImage, open log to see whether there exist any problem.

Regards,

Alan Zhang

[winstonrodrigue]

Hi Xia Zhang ,

            Thanks for your valuable suggestions. I did what you told me to do. but UART4 and UART5 are stil not working.

even when i connect oscilloscope on RX/TX pins there are no signal changes on the pins. but UART3/UART2/UART1 gives perfect signals.

         I have another idea ......

    by referring to the i.MX53 Multimedia Applications Processor Reference Manual, Rev. 2,.1, 6/2012

  section 45.51.1 Configuration Register (IPU_CONF)

   so this register is responsible for IPU interface initialization.

   so in this 32 bit register the 0th and 1st bits are responsible for enabling / disabling the CSI0 and CSI1 interfaces.

So i was just wondering if its possible to read / write this register or by OR-ing the value by 0x11111110 disables both the CSI interfaces. I think we can use __raw_writel(data,address);

  Any thoughts?

   Regards,

     Winston

[AlanZhang]

One more configuration item in kernel configuration file is needed to be "n", i.e. CONFIG_VIDEO_MXC_IPU_CAMERA=n.

Regards,

Alan Zhang

[winstonrodrigue]

Hi....

where can I find the kernel configuration file ??

thanks for the speedy reply ...

regards,

  Winston

[AlanZhang]

Under kernel/arch/arm/configs/imx5_defconfig, or imx5_android_defconfig.

Regards,

Alan Zhang

[winstonrodrigue]

Dear Xia Zhang,

                I modified the kernel config file, rebuilt the kernel and booted. but no output on UART4 and UART5.

there is one more thing...

   on this SABRE board  in root directory /unit_test directory

   when i run mxc_uart_test.out it looks like the UART4 and UART5 are working for IOCTL test..

for UART5

root@freescale /unit_tests$ ./mxc_uart_test.out /dev/ttymxc4
Test: MXC UART!

Usage: mxc_uart_test <UART device name, opens UART2 if no dev name is specified>

/dev/ttymxc4 opened
Attributes set
Test: IOCTL Set
Data Written= Test

Data Read back= Test

for UART4

root@freescale /unit_tests$ ./mxc_uart_test.out /dev/ttymxc3
Test: MXC UART!

Usage: mxc_uart_test <UART device name, opens UART2 if no dev name is specified>

/dev/ttymxc3 opened
Attributes set
Test: IOCTL Set
Data Written= Test

Data Read back= Test

So it looks like there is no prob in UARTS. so there must be problem in Pin settings or something..... ..

what else can be done ?

Regards,

  Winston.

[AlanZhang]

Good feedback! Could you check drivers/serial/mxc_uart.c file, insert printk() in .start_tx, .set_mctrl, and .set_termios to see whether the invocations are in there. NO hardware flow control involved, unless RTS is connected to CTS directly.

Regards,

Alan Zhang

[winstonrodrigue]

Dear Alan Zhang,

here is the modified mxc_uart.c file..

static void mxcuart_start_tx(struct uart_port *port)

{

    uart_mxc_port *umxc = (uart_mxc_port *) port;

    struct circ_buf *xmit = &umxc->port.state->xmit;

    volatile unsigned int cr1;

    mxc_dma_requestbuf_t writechnl_request;

    int tx_num;

        printk("transmitting\n");

    cr1 = readl(port->membase + MXC_UARTUCR1);

    /* Enable Transmitter rdy interrupt */

    if (umxc->dma_enabled == 1) {

        /*

         * If the channel is in use then return immediately and use

         * the mxcuart_dma_tx to transfer queued data when current DMA

         * transfer is complete

         */

        if (dma_list[umxc->port.line].dma_txchnl_inuse == 1) {

            return;

                 printk("channel is in use\n");

        }

        tx_num = uart_circ_chars_pending(xmit);

        if (tx_num > 0) {

            dma_list[umxc->port.line].dma_txchnl_inuse = 1;

            if (xmit->tail > xmit->head) {

                memcpy(umxc->tx_buf, xmit->buf + xmit->tail,

                       UART_XMIT_SIZE - xmit->tail);

                memcpy(umxc->tx_buf +

                       (UART_XMIT_SIZE - xmit->tail), xmit->buf,

                       xmit->head);

            } else {

                memcpy(umxc->tx_buf, xmit->buf + xmit->tail,

                       tx_num);

            }

            umxc->tx_handle =

                dma_map_single(umxc->port.dev, umxc->tx_buf,

                       TXDMA_BUFF_SIZE, DMA_TO_DEVICE);

                          printk("transmitt- wintu\n");

            writechnl_request.dst_addr =

                umxc->port.mapbase + MXC_UARTUTXD;

            writechnl_request.src_addr = umxc->tx_handle;

            writechnl_request.num_of_bytes = tx_num;

            if ((mxc_dma_config

                 (dma_list[umxc->port.line].wr_channel,

                  &writechnl_request, 1,

                  MXC_DMA_MODE_WRITE)) == 0) {

                mxc_dma_enable(dma_list[umxc->port.line].

                           wr_channel);

            }

            cr1 |= MXC_UARTUCR1_TXDMAEN;

        }

    } else {

        cr1 |= MXC_UARTUCR1_TRDYEN;

    }

    writel(cr1, port->membase + MXC_UARTUCR1);

}

Now when i use ttymxc2 (UART3) /UART1 /UART0 im getting

"transmitting"

"transmit -wintu" strings displayed... which means no problem.

but when i use UART4/UART5 i.e. ttymxc4 and ttymxc3  im getting only

"transmitting"

which means its not coming in the if (umxc->dma_enabled == 1) loop at all..

which means umxc->dma_enabled is not going 1..

whats the problem ?

Regards,

   Winston

[AlanZhang]

The configurations for serial port 0 ~ 4 is defined in arch/arm/mach-mx5/serial.c file, where you change the dma_enable to 0 for both port 4 and port 5, then whether these  ports are ok now. If it works, so we will check whether  the DMA config is proper for port 4 and port 5.

Regards,

Alan Zhang

[winstonrodrigue]

Dear Xia Zhang,

         I changed the dma_enable to 0 and tried as u said.. But no luck its same as before.

  then I changed the dma_enabled to 1 .

  Now also there is no output signals on the TX rx pins.

    But its not coming into this loop in (mxc_uart.c).

        if (xmit->tail > xmit->head) {

                memcpy(umxc->tx_buf, xmit->buf + xmit->tail,

                       UART_XMIT_SIZE - xmit->tail);

                printk("transmit-UART_XMIT\n");

                memcpy(umxc->tx_buf +

                       (UART_XMIT_SIZE - xmit->tail), xmit->buf,

                       xmit->head);

  in abovve code printk statement is not executed.

  but its coming into this if loop without any problem ....

     if ((mxc_dma_config

                 (dma_list[umxc->port.line].wr_channel,

                  &writechnl_request, 1,

                  MXC_DMA_MODE_WRITE)) == 0) {

               printk("MXC_DMA_MODE\n");

                mxc_dma_enable(dma_list[umxc->port.line].

                           wr_channel);

  in this code printk statement is executed. 

  Regards,

   Winston

[AlanZhang]

HI, Winston,

Could you insert checkpoints into :

	mxc_ports[id]->clk = clk_get(&pdev->dev, NULL);
	if (mxc_ports[id]->clk == NULL) {     printk("No clock for this port.\n");
		return -1; }

static void mxcuart_dma_tx(uart_mxc_port *umxc)

{

......

	if ((mxc_dma_config(dma_list[umxc->port.line].wr_channel,
		&writechnl_request, 1,
		MXC_DMA_MODE_WRITE)) == 0) {
		mxc_dma_enable(dma_list[umxc->port.line].wr_channel); printk("checkpoint 1.\n");
	}

}

static void mxcuart_dma_writecallback(void *arg, int error, unsigned int count)

{

......

}

static void mxcuart_stop_tx(struct uart_port *port)

{

}

static void mxcuart_tx_chars(uart_mxc_port *umxc)

{

}

static irqreturn_t mxcuart_int(int irq, void *dev_id)

{

     insert printk to see whether interrupt is coming up.

}

[winstonrodrigue]

Dear Xia Zhang,

      As you suggested, I inserted printk into all of the places mentioned above.

by seeing the output.

   all of the UARTS ports are executing throgh mxcuart_dma_writecallback

and the below functions are executed only during the startup...

static void mxcuart_stop_tx(struct uart_port *port)

{

}

static void mxcuart_tx_chars(uart_mxc_port *umxc)

{

}

static irqreturn_t mxcuart_int(int irq, void *dev_id)

{

     insert printk to see whether interrupt is coming up.

}

but stil no output on UART4 and UART5.

thanks .

Winston

[AlanZhang · Accepted solution]

Hi, Winston,

If as you said that all UART ports behave in the same way from the perspective of code flow, but no signals output on uart #4 and uart #5. So are you sure that the hardware connection are ok, and no active long low voltage on rx, tx pins at the init phase. How about the rts/cts voltage level? If all of these checklist are ok, we have to change uart4, and 5 to other alternative pins. Whether it is ok to ship one board to me?

Regards,

Alan Zhang

[winstonrodrigue]

Hi Xia Zhang,

        I think I found the problem.... Actually I have no idea if UART4 and UART5 are workng fine.. but

I have beent esting the UART4 and uart5 on J78 120 pin QTH connector on imx53_smd board.

   If i look at the schematic of the board i came to a conclusion that the UART4 and UART5 signals are not at all conneted to CPU.

picture of the J78 is attached.

i.e. for UART4 -- 26th and 28th pin

           UART5 - 32 and 34th pin. which are not connected anywhere.....

So no point in testing the UART4 and UART5...

Do u have any suggestions on how can i route the UART4 and UART5 pins to some other pins on the same connector. ?

[AlanZhang]

Hi, Winston,

You referred to a wrong connector. According to IOMUX config, the nets of UART 4 and 5 are associated with the connector J12, not J78. J12 is a CSI connector that you need to be very careful to wire out nets from it. So I suggest you to prepare an real customized board that follows your hardware spec, then let discuss on that real board.

Regards,

Alan Zhang