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

[Zoran Stojsavljevic]

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

So, as I assumed, SC_GP_LVL is WR ONLY register. If it always works and
puts out values, and retains them (which is another of mine assumption),
the solution to RD problem is simplistic.

Immediately after the: outl(GPIO, gpiobase + GPIO_SC_GP_LVL);

Please, always remember the I/O data value you outl() into some heap global
variable (which will always retain the latest outl() data value). If you
need it back, read this variable.

Best Regards,
Zoran

On Mon, Jul 18, 2016 at 7:20 AM, 김유석  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-microserve...
>
> And read Chapter 25 - General Purpose I/O (GPIO).
>
> Best Regards,
> Zoran
>
> On Wed, Jul 13, 2016 at 6:39 AM, 김유석  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.