Re: [coreboot] How to read the gpio status? - coreboot

20 Jul 2016

      Dear Zoran.
_I was perectly understand the I2C algo_. It is very easy to me.
And I was know that I2C_DATA line is must need a mode 
change(INPUT/OUTPUT) for bidirectional communication.
*At present, I2C is not important to me.*
I want to say. that my purpose is just control GPIO pins.
My problem is...
Suppose this sistuation.
Initial status of gpio
pin
    SC_IO_SEL
    SC_GP_LVL
GPIO_11(reset of some ic)
    output
    HIGH
GPIO_12(LED1)
    output
    LOW
GPIO_13(detect pin)
    input
    HIGH
After power-on. suppose, must need turn on  the GPIO_12(LED1).
It is easy.
void led_control(u32 pin_num)
{
    u32 current_status = inl(gbase + SC_GP_LVL);
    current_status = setbit(current_status, pin_num);
}
*But, My case is can't read status of outputmode pins.*
      Can read the status of *inputmode pins*.
ButCan't read the status of *outputmode pins.*
current status is very important information for bit operation(set/clear).
GPIO_11 is output mode => can't read this status.
   GPIO_12 is output mode => can't read this status.
GPIO_13 is input mode => can read this status.
If I try to control without knowing the current state, *must becomes 
problem.*
So, I try to find the solution that "How to read the status of 
outputmode gpio pins"
Another platform is can get a status of pin. use by "register of IO 
direction" and "register of IO Level".
If I use the AND operation, can get a status of output mode pins.
Please any idea?
Thank you.
2016-07-20 오후 3:56에 Zoran Stojsavljevic 이(가) 쓴 글:
...
Hello Kim,
Kim, listen to me/read me now very carefully. Please. :-)
For the standard I2C interface, you have only two serial lines: 
I2C_CLK and I2C_DATA. Your C2000 is master, so it will ALWAYS provide 
I2C_CLK as OUT. With I2C_DATA things are a bit more complicated. It is 
IN/OUT line, and once you output on it, you MUST turn it around.
I'll provide to you an adequate example. Let us assume SC_USE_SEL has 
two dedicated IO_14 as I2C_CLK, and IO_13 as I2C_DATA.
For the I2C_CLK, it is always output. For I2C_DATA, it is bidirectional.
So, when you supply slave I2C address on the bus, the following is true:
GPIO_SC_USE_SEL : 6000
GPIO_SC_IO_SEL : 0 (all pins as OUT direction)
GPIO_SC_GP_LVL : bit banging on pins 13, 14
Now, you need to turn around your data bus, to be IN. Here is the 
situation:
GPIO_SC_USE_SEL : 6000
GPIO_SC_IO_SEL : 2000 (pin 13 is now defined as IN direction!)
GPIO_SC_GP_LVL : answer coming on pin 13, you have to sample it 
correctly in time READing this register (only bit 13 is valid) and 
looking into bit 13 value).
You might try it. And I rest my case here, Kim!
Zoran
On Wed, Jul 20, 2016 at 6:52 AM, 김유석 <poplinux0@gmail.com 
mailto:poplinux0@gmail.com> wrote:
Dear Sir.

I'm understand your worry.

My phase is develop the raw level API for gpio control.
SW I2C is will use the raw level API. SW I2C is will implementation.

I was set the SC_USE_SEL, and SC_IO_SEL. correctly.

And I already check the some function.
  1. outmode => is OK.
      If i set the HIGH on 12, 13, 14. then i can saw the HIGH
status using ocilloscope.
      If i set the LOW on 12, 13, 14. then i can saw the LOW
status using ocilloscope.
  2. input mode => is OK.
      If i assign the 3.3V to 12, 13, 14. then i can read the
SC_GP_LVL(0x7000).
      If i assign the 0V to 12, 13, 14. then i can read the
SC_GP_LVL(0x00)

But just one function is fail.

 step 1. set the output mode. => is success
 step 2. set the level. => is success
 step 3. read the current config of SC_GP_LVL => is fail.
        if if write 0x7000 to SC_GP_LVL, I want to read the value
0x7000 from SC_GP_LVL. But i can't

Thank you.

2016-07-19 오후 9:12에 Zoran Stojsavljevic 이(가) 쓴 글:

...
Hey Kim,

You have forced me myself to read the manual (chapter 25, C2000
Data Sheet). I was really wondering... So I decided to spend some
time and read it myself (anyway, I have some time, albeit I do
some other stuff). ;-)

There is description of two power domains there, which I/O are
using in order to drive customer I/O wishes. Two of them are:
Core Well and SUS Well. You are using Core Well GPIOs, namely
they are described in Ch. 25.3.1:
Choosing the native Signal Mode or Customer GPIO Mode.

Inline image 1
Questions here: did you set properly register: SC_USE_SEL? Your
bits 12/13/14 should be in this register 1s (x111 xxxx xxxx xxxx
binary), and you need to set also properly SC_IO_SEL register
(them to be outputs). I am now looking into your code, and it
seems you did it correctly (three OUT values):
 GPIO_SC_USE_SEL : 7000
GPIO_SC_IO_SEL  : 0
GPIO_SC_GP_LVL  : 0

Then you output your OUT values. Hmmmmmm... Considering I2C, you
inevitable should read some INPUT values?! Which pins these are?
You should have from master (your C2000) to supply CLK and OUT,
but you also need to read IN values... Don't you???

I do NOT see input from I2C slave device... Any thoughts (any ideas)?

Zoran

On Mon, Jul 18, 2016 at 7:20 AM, 김유석 <poplinux0@gmail.com
<mailto:poplinux0@gmail.com>> wrote:

    Dear Sir.

    I was test with by your advise. But SC_GP_LVL is always read 0x00

    source code & result is see below.

      u32 read_gpio_level(const struct soc_gpio_map *gpio)
      {

        u16 gpiobase __attribute__((unused)) =
    pci_read_config16(SOC_LPC_DEV, GBASE) & ~0xf;

        printk(BIOS_DEBUG, "%s() : Start\n", __FUNCTION__);
        printk(BIOS_DEBUG, " GPIO_SC_USE_SEL : 0x%x\n",
    inl(gpiobase + GPIO_SC_USE_SEL));
        printk(BIOS_DEBUG, " GPIO_SC_IO_SEL  : 0x%x\n",
    inl(gpiobase + GPIO_SC_IO_SEL));
        printk(BIOS_DEBUG, " GPIO_SC_GP_LVL  : 0x%x\n",
    inl(gpiobase + GPIO_SC_GP_LVL));
        printk(BIOS_DEBUG, "%s() : End\n\n", __FUNCTION__);

        return 0;
      }

      int set_gpio_level(const struct soc_gpio_map *gpio,
                         const int num,
                         const int lvl)
      {
        u16 gpiobase __attribute__((unused)) =
    pci_read_config16(SOC_LPC_DEV, GBASE) & ~0xf;
        u32 GPIO = 0;

        GPIO = setBit(GPIO, num);

        printk(BIOS_DEBUG, "%s() : GPIO set value 0x%x\n",
    __FUNCTION__, GPIO);
        outl(GPIO, gpiobase + GPIO_SC_GP_LVL);

        return 0;
      }

      void early_mainboard_romstage_entry(void)
      {
    setup_soc_gpios(&gpio_map);
        set_gpio_level(&gpio_map, 12, 1);
        mdelay(500);
    read_gpio_level(&gpio_map);

        set_gpio_level(&gpio_map, 13, 1);
        mdelay(500);
    read_gpio_level(&gpio_map);

        set_gpio_level(&gpio_map, 14, 1);
        mdelay(500);
    read_gpio_level(&gpio_map);
      };

    ==================================================================================
      coreboot-NexG-59a9b0a6 Mon Jul 18 05:09:30 UTC 2016
    romstage starting...
      set_gpio_level() : GPIO set value 0x1000
      read_gpio_level() : Start
        GPIO_SC_USE_SEL : 7000
        GPIO_SC_IO_SEL  : 0
        GPIO_SC_GP_LVL  : 0
      read_gpio_level() : End

      set_gpio_level() : GPIO set value 0x2000
      read_gpio_level() : Start
        GPIO_SC_USE_SEL : 7000
        GPIO_SC_IO_SEL  : 0
        GPIO_SC_GP_LVL  : 0
      read_gpio_level() : End

      set_gpio_level() : GPIO set value 0x4000
      read_gpio_level() : Start
        GPIO_SC_USE_SEL : 7000
        GPIO_SC_IO_SEL  : 0
        GPIO_SC_GP_LVL  : 0
      read_gpio_level() : End

    And I was re-view the DS of C2000.

    But DS is said to me that SC_GP_LVL is WR register.

    Please help me.

    Thank you.

    2016-07-13 오후 4:40에 Zoran Stojsavljevic 이(가) 쓴 글:

...
    *_> When write 0x7000 write to SC_GP_LVL, Can read the 0x00
    from SC_GP_LVL. everytime._*

    Please, try to do the following exercise:

    [1] WR 0x1000 to SC_GP_LVL, then RD the value out of it:
    what it is?
    [2] WR 0x2000 to SC_GP_LVL, then RD the value out of it:
    what it is?
    [3] WR 0x4000 to SC_GP_LVL, then RD the value out of it:
    what it is?

    If you have all 0x0, most likely it does mean that
    Rangeley's SC_GP_LVL register isd WR ONLY (when you read it,
    all 0s).

    To verify this, you should fetch the following document:
    http://www.intel.com/content/www/us/en/processors/atom/atom-c2000-microserver-datasheet.html

    And read Chapter 25 - General Purpose I/O (GPIO).

    Best Regards,
    Zoran

    On Wed, Jul 13, 2016 at 6:39 AM, 김유석 <poplinux0@gmail.com
    <mailto:poplinux0@gmail.com>> wrote:

        Dear Sir.

        I want to control the GPIO pin that pin number is 12, 13, 14

        DataSheet(P 1909) and coreboot source
        code(src/southbridge/intel/fsp_rangeley/gpio.c, gpio.h)
        is said to me that "It is very easy"

        If i want to set the HIGH to 12, 13, 14

        Just setup the some register, is see below.

        SC_USE_SEL = 0x7000(b0111 0000 0000 0000)

            Is mean, the 12, 13, 14 is config to GPIO
        mode.(enable GPIO)

        SC_IO_SEL = 0x00(b0000 0000 0000 0000)

            Is mean, the 12, 13, 14 is output mode

        SC_GP_LVL = 0x7000(b0111 0000 0000 0000)

            Is mean, the 12, 13, 14 is set to HIGH level(1)

        src/southbridge/intel/fsp_rangeley/gpio.h

          /* Core GPIO */
          const struct soc_gpio soc_gpio_mode = {
            .gpio12 = GPIO_MODE_GPIO, /* Board ID GPIO */
            .gpio13 = GPIO_MODE_GPIO, /* Board ID GPIO */
            .gpio14 = GPIO_MODE_GPIO, /* Board ID GPIO */
          };

          const struct soc_gpio soc_gpio_direction = {
            .gpio12 = GPIO_DIR_OUTPUT,
            .gpio13 = GPIO_DIR_OUTPUT,
            .gpio14 = GPIO_DIR_OUTPUT,
          };

          const struct soc_gpio soc_gpio_level = {
            .gpio12 = GPIO_LEVEL_HIGH,
            .gpio13 = GPIO_LEVEL_HIGH,
            .gpio14 = GPIO_LEVEL_HIGH,
          };

        Yes, It is perfectley running.

        The 12, 13, 14 PIN is goto active-HIGH.(I was check this
        pin use by oscilloscope.)

        And I'm try to read the SC_GP_LVL register for check
        current status/config of gpio pins

        I was *respected* the read value is *0x7000*, because i
        was writed the *0x7000* to SC_GP_LVL.

        But, every time readed the *0x00* from SC_GP_LVL register.

        _When write 0x7000 write to SC_USE_SEL, Can read the
        0x7000 from SC_USE_SEL._

        _When write 0x00 write to SC_IO_SEL, Can read the 0x00
        from SC_IO_SEL._

        But,

        *_When write 0x7000 write to SC_GP_LVL, Can read the
        0x00 from SC_GP_LVL. everytime._*

        I don't understand this sistuation.

        Please advise to me.

        Thank you.

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