text: /*
  Copyright (c) 2012-2015 Ben Croston
  
  Permission is hereby granted, free of charge, to any person obtaining a copy of
  this software and associated documentation files (the "Software"), to deal in
  the Software without restriction, including without limitation the rights to
  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
  of the Software, and to permit persons to whom the Software is furnished to do
  so, subject to the following conditions:
  
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
  
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.
  */
  
  #include <stdio.h>
  #include <stdint.h>
  #include <stdlib.h>
  #include <fcntl.h>
  #include <sys/mman.h>
  #include <string.h>
  #include "c_gpio.h"
  
  #define BCM2708_PERI_BASE_DEFAULT   0x20000000
  #define BCM2709_PERI_BASE_DEFAULT   0x3f000000
  #define GPIO_BASE_OFFSET            0x200000
  #define FSEL_OFFSET                 0   // 0x0000
  #define SET_OFFSET                  7   // 0x001c / 4
  #define CLR_OFFSET                  10  // 0x0028 / 4
  #define PINLEVEL_OFFSET             13  // 0x0034 / 4
  #define EVENT_DETECT_OFFSET         16  // 0x0040 / 4
  #define RISING_ED_OFFSET            19  // 0x004c / 4
  #define FALLING_ED_OFFSET           22  // 0x0058 / 4
  #define HIGH_DETECT_OFFSET          25  // 0x0064 / 4
  #define LOW_DETECT_OFFSET           28  // 0x0070 / 4
  #define PULLUPDN_OFFSET             37  // 0x0094 / 4
  #define PULLUPDNCLK_OFFSET          38  // 0x0098 / 4
  
  #define PAGE_SIZE  (4*1024)
  #define BLOCK_SIZE (4*1024)
  
  static volatile uint32_t *gpio_map;
  
  #ifndef BPI
  #define BPI
  #endif
  
  #ifdef BPI
  extern int bpi_found;
  extern int bpi_found_mtk;
  extern int *pinTobcm_BP ;
  #endif
  
  void short_wait(void)
  {
      int i;
  
      for (i=0; i<150; i++) {    // wait 150 cycles
          asm volatile("nop");
      }
  }
  
  int setup(void)
  {
      int mem_fd;
      uint8_t *gpio_mem;
      uint32_t peri_base;
      uint32_t gpio_base;
      unsigned char buf[4];
      FILE *fp;
      char buffer[1024];
      char hardware[1024];
      int found = 0;
  
  #ifdef BPI
      if( bpi_found == 1 ) {
  	if( bpi_found_mtk == 1){
              return mtk_setup();
  	}
  	return sunxi_setup();
      }
  #endif
      // try /dev/gpiomem first - this does not require root privs
      if ((mem_fd = open("/dev/gpiomem", O_RDWR|O_SYNC)) > 0)
      {
          gpio_map = (uint32_t *)mmap(NULL, BLOCK_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, mem_fd, 0);
          if ((uint32_t)gpio_map < 0) {
              return SETUP_MMAP_FAIL;
          } else {
              return SETUP_OK;
          }
      }
  
      // revert to /dev/mem method - requires root
  
      // determine peri_base
      if ((fp = fopen("/proc/device-tree/soc/ranges", "rb")) != NULL) {
          // get peri base from device tree
          fseek(fp, 4, SEEK_SET);
          if (fread(buf, 1, sizeof buf, fp) == sizeof buf) {
              peri_base = buf[0] << 24 | buf[1] << 16 | buf[2] << 8 | buf[3] << 0;
          }
          fclose(fp);
      } else {
          // guess peri base based on /proc/cpuinfo hardware field
          if ((fp = fopen("/proc/cpuinfo", "r")) == NULL)
              return SETUP_CPUINFO_FAIL;
  
          while(!feof(fp) && !found) {
              fgets(buffer, sizeof(buffer), fp);
              sscanf(buffer, "Hardware	: %s", hardware);
              if (strcmp(hardware, "BCM2708") == 0 || strcmp(hardware, "BCM2835") == 0) {
                  // pi 1 hardware
                  peri_base = BCM2708_PERI_BASE_DEFAULT;
                  found = 1;
              } else if (strcmp(hardware, "BCM2709") == 0 || strcmp(hardware, "BCM2836") == 0) {
                  // pi 2 hardware
                  peri_base = BCM2709_PERI_BASE_DEFAULT;
                  found = 1;
              }
          }
          fclose(fp);
          if (!found)
              return SETUP_NOT_RPI_FAIL;
      }
  
      gpio_base = peri_base + GPIO_BASE_OFFSET;
  
      // mmap the GPIO memory registers
      if ((mem_fd = open("/dev/mem", O_RDWR|O_SYNC) ) < 0)
          return SETUP_DEVMEM_FAIL;
  
      if ((gpio_mem = malloc(BLOCK_SIZE + (PAGE_SIZE-1))) == NULL)
          return SETUP_MALLOC_FAIL;
  
      if ((uint32_t)gpio_mem % PAGE_SIZE)
          gpio_mem += PAGE_SIZE - ((uint32_t)gpio_mem % PAGE_SIZE);
  
      gpio_map = (uint32_t *)mmap( (void *)gpio_mem, BLOCK_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_FIXED, mem_fd, gpio_base);
  
      if ((uint32_t)gpio_map < 0)
          return SETUP_MMAP_FAIL;
  
      return SETUP_OK;
  }
  
  void clear_event_detect(int gpio)
  {
      int offset = EVENT_DETECT_OFFSET + (gpio/32);
      int shift = (gpio%32);
  
  #ifdef BPI
      if( bpi_found == 1 ) {
          return;
  	} 
  #endif
      *(gpio_map+offset) |= (1 << shift);
      short_wait();
      *(gpio_map+offset) = 0;
  }
  
  int eventdetected(int gpio)
  {
      int offset, value, bit;
  
  #ifdef BPI
      if( bpi_found == 1 ) {
          return;
  	} 
  #endif
      offset = EVENT_DETECT_OFFSET + (gpio/32);
      bit = (1 << (gpio%32));
      value = *(gpio_map+offset) & bit;
      if (value)
          clear_event_detect(gpio);
      return value;
  }
  
  void set_rising_event(int gpio, int enable)
  {
      int offset = RISING_ED_OFFSET + (gpio/32);
      int shift = (gpio%32);
  
  #ifdef BPI
      if( bpi_found == 1 ) {
          return;
  	} 
  #endif
      if (enable)
          *(gpio_map+offset) |= 1 << shift;
      else
          *(gpio_map+offset) &= ~(1 << shift);
      clear_event_detect(gpio);
  }
  
  void set_falling_event(int gpio, int enable)
  {
      int offset = FALLING_ED_OFFSET + (gpio/32);
      int shift = (gpio%32);
  
  #ifdef BPI
      if( bpi_found == 1 ) {
          return;
  	} 
  #endif
      if (enable) {
          *(gpio_map+offset) |= (1 << shift);
          *(gpio_map+offset) = (1 << shift);
      } else {
          *(gpio_map+offset) &= ~(1 << shift);
      }
      clear_event_detect(gpio);
  }
  
  void set_high_event(int gpio, int enable)
  {
      int offset = HIGH_DETECT_OFFSET + (gpio/32);
      int shift = (gpio%32);
  
  #ifdef BPI
      if( bpi_found == 1 ) {
          return;
  	}
  #endif
      if (enable)
          *(gpio_map+offset) |= (1 << shift);
      else
          *(gpio_map+offset) &= ~(1 << shift);
      clear_event_detect(gpio);
  }
  
  void set_low_event(int gpio, int enable)
  {
      int offset = LOW_DETECT_OFFSET + (gpio/32);
      int shift = (gpio%32);
  
  #ifdef BPI
      if( bpi_found == 1 ) {
          return;
  	} 
  #endif
      if (enable)
          *(gpio_map+offset) |= 1 << shift;
      else
          *(gpio_map+offset) &= ~(1 << shift);
      clear_event_detect(gpio);
  }
  
  void set_pullupdn(int gpio, int pud)
  {
      int clk_offset = PULLUPDNCLK_OFFSET + (gpio/32);
      int shift = (gpio%32);
  
  #ifdef BPI
      if( bpi_found == 1 ) {
          gpio = *(pinTobcm_BP + gpio);
          return sunxi_set_pullupdn(gpio, pud);
      }
  #endif
      if (pud == PUD_DOWN)
          *(gpio_map+PULLUPDN_OFFSET) = (*(gpio_map+PULLUPDN_OFFSET) & ~3) | PUD_DOWN;
      else if (pud == PUD_UP)
          *(gpio_map+PULLUPDN_OFFSET) = (*(gpio_map+PULLUPDN_OFFSET) & ~3) | PUD_UP;
      else  // pud == PUD_OFF
          *(gpio_map+PULLUPDN_OFFSET) &= ~3;
  
      short_wait();
      *(gpio_map+clk_offset) = 1 << shift;
      short_wait();
      *(gpio_map+PULLUPDN_OFFSET) &= ~3;
      *(gpio_map+clk_offset) = 0;
  }
  
  void setup_gpio(int gpio, int direction, int pud)
  {
  
  #ifdef BPI
      if( bpi_found == 1 ) {
          gpio = *(pinTobcm_BP + gpio);
  	if(bpi_found_mtk == 1){
  		return;
  	}else{
  		return sunxi_setup_gpio(gpio, direction, pud);
  	}
          
      }
      else {
  #endif
      int offset = FSEL_OFFSET + (gpio/10);
      int shift = (gpio%10)*3;
  
      set_pullupdn(gpio, pud);
      if (direction == OUTPUT)
          *(gpio_map+offset) = (*(gpio_map+offset) & ~(7<<shift)) | (1<<shift);
      else  // direction == INPUT
          *(gpio_map+offset) = (*(gpio_map+offset) & ~(7<<shift));
  #ifdef BPI
      }
  #endif
  }
  
  // Contribution by Eric Ptak <trouch@trouch.com>
  int gpio_function(int gpio)
  {
  #ifdef BPI
      if( bpi_found == 1 ) {
         gpio = *(pinTobcm_BP + gpio);
  	if(bpi_found_mtk == 1){
  		return;
  	}else{
  		return sunxi_gpio_function(gpio);
  	}
         
      }
      else {
  #endif
      int offset = FSEL_OFFSET + (gpio/10);
      int shift = (gpio%10)*3;
      int value = *(gpio_map+offset);
  
      value >>= shift;
      value &= 7;
      return value; // 0=input, 1=output, 4=alt0
  #ifdef BPI	
      }
  #endif
  }
  
  void output_gpio(int gpio, int value)
  {
      int offset, shift;
  
  #ifdef BPI
      if ( bpi_found == 1)  {
  	printf("gpio = %d, value = %d\n", gpio, value);
  	gpio = *(pinTobcm_BP + gpio);
  	printf("gpio = %d, value = %d\n", gpio, value);
  	if(bpi_found_mtk ==  1){
  		mtk_set_gpio_out(gpio, value);
  	}else{
  	       sunxi_output_gpio(gpio, value);
  	}
         return;
      }
  #endif	
      if (value) // value == HIGH
          offset = SET_OFFSET + (gpio/32);
      else       // value == LOW
         offset = CLR_OFFSET + (gpio/32);
  
      shift = (gpio%32);
  
      *(gpio_map+offset) = 1 << shift;
  }
  
  int input_gpio(int gpio)
  {
     int offset, value, mask;
  
  
  #ifdef BPI
     if ( bpi_found == 1)  {
        gpio = *(pinTobcm_BP + gpio);
        return sunxi_input_gpio(gpio);
     }
  #endif	
     offset = PINLEVEL_OFFSET + (gpio/32);
     mask = (1 << gpio%32);
     value = *(gpio_map+offset) & mask;
     return value;
  }
  
  void cleanup(void)
  {
      munmap((void *)gpio_map, BLOCK_SIZE);
  }
  