libopenbmc_intf/gpio.c - openbmc/skeleton - Gitiles

 #define _GNU_SOURCE

 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <argp.h>
 #include <sys/stat.h>
 #include <sys/mman.h>
 #include <dirent.h>
 #include "openbmc_intf.h"
 #include "gpio.h"
 #include "gpio_json.h"

 #include <sys/ioctl.h>
 #include <linux/gpio.h>

 #define GPIO_PORT_OFFSET 8
 #define GPIO_BASE_PATH "/sys/class/gpio"

 cJSON* gpio_json = NULL;

 int gpio_write(GPIO* gpio, uint8_t value)
 {
 	g_assert (gpio != NULL);
 	struct gpiohandle_data data;
 	memset(&data, 0, sizeof(data));
 	data.values[0] = value;

 	if (gpio->fd <= 0)
 	{
 		return GPIO_ERROR;
 	}

 	if (ioctl(gpio->fd, GPIOHANDLE_SET_LINE_VALUES_IOCTL, &data) < 0)
 	{
 		return GPIO_WRITE_ERROR;
 	}

 	return GPIO_OK;
 }

 int gpio_read(GPIO* gpio, uint8_t *value)
 {
 	g_assert (gpio != NULL);
 	struct gpiohandle_data data;
 	memset(&data, 0, sizeof(data));

 	if (gpio->fd <= 0)
 	{
 		return GPIO_ERROR;
 	}

 	if (ioctl(gpio->fd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, &data) < 0)
 	{
 		return GPIO_READ_ERROR;
 	}

 	*value = data.values[0];

 	return GPIO_OK;
 }

 /**
  * Determine the GPIO base number for the system.  It is found in
  * the 'base' file in the /sys/class/gpio/gpiochipX/ directory where the
  * /sys/class/gpio/gpiochipX/label file has a '1e780000.gpio' in it.
  *
  * Note: This method is ASPEED specific.  Could add support for
  * additional SOCs in the future.
  *
  * @return int - the GPIO base number, or < 0 if not found
  */
 int get_gpio_base()
 {
 	int gpio_base = -1;

 	DIR* dir = opendir(GPIO_BASE_PATH);
 	if (dir == NULL)
 	{
 		fprintf(stderr, "Unable to open directory %s\n",
 				GPIO_BASE_PATH);
 		return -1;
 	}

 	struct dirent* entry;
 	while ((entry = readdir(dir)) != NULL)
 	{
 		/* Look in the gpiochip<X> directories for a file called 'label' */
 		/* that contains '1e780000.gpio', then in that directory read */
 		/* the GPIO base out of the 'base' file. */

 		if (strncmp(entry->d_name, "gpiochip", 8) != 0)
 		{
 			continue;
 		}

 		gboolean is_bmc = FALSE;
 		char* label_name;
 		asprintf(&label_name, "%s/%s/label",
 				GPIO_BASE_PATH, entry->d_name);

 		FILE* fd = fopen(label_name, "r");
 		free(label_name);

 		if (!fd)
 		{
 			continue;
 		}

 		char label[14];
 		if (fgets(label, 14, fd) != NULL)
 		{
 			if (strcmp(label, "1e780000.gpio") == 0)
 			{
 				is_bmc = TRUE;
 			}
 		}
 		fclose(fd);

 		if (!is_bmc)
 		{
 			continue;
 		}

 		char* base_name;
 		asprintf(&base_name, "%s/%s/base",
 				GPIO_BASE_PATH, entry->d_name);

 		fd = fopen(base_name, "r");
 		free(base_name);

 		if (!fd)
 		{
 			continue;
 		}

 		if (fscanf(fd, "%d", &gpio_base) != 1)
 		{
 			gpio_base = -1;
 		}
 		fclose(fd);

 		/* We found the right file. No need to continue. */
 		break;
 	}
 	closedir(dir);

 	if (gpio_base == -1)
 	{
 		fprintf(stderr, "Could not find GPIO base\n");
 	}

 	return gpio_base;
 }

 /**
  * Converts the GPIO port/offset nomenclature value
  * to a number.  Supports the ASPEED method where
  * num = base + (port * 8) + offset, and the port is an
  * A-Z character that converts to 0 to 25.  The base
  * is obtained form the hardware.
  *
  * For example: "A5" -> 5,  "Z7" -> 207
  *
  * @param[in] gpio - the GPIO name
  *
  * @return int - the GPIO number or < 0 if not found
  */
 int convert_gpio_to_num(const char* gpio)
 {
 	size_t len = strlen(gpio);
 	if (len < 2)
 	{
 		fprintf(stderr, "Invalid GPIO name %s\n", gpio);
 		return -1;
 	}

 	/* Read the offset from the last character */
 	if (!isdigit(gpio[len-1]))
 	{
 		fprintf(stderr, "Invalid GPIO offset in GPIO %s\n", gpio);
 		return -1;
 	}

 	int offset = gpio[len-1] - '0';

 	/* Read the port from the second to last character */
 	if (!isalpha(gpio[len-2]))
 	{
 		fprintf(stderr, "Invalid GPIO port in GPIO %s\n", gpio);
 		return -1;
 	}
 	int port = toupper(gpio[len-2]) - 'A';

 	/* Check for a 2 character port, like AA */
 	if ((len == 3) && isalpha(gpio[len-3]))
 	{
 		port += 26 * (toupper(gpio[len-3]) - 'A' + 1);
 	}

 	return (port * GPIO_PORT_OFFSET) + offset;
 }

 /**
  * Returns the cJSON pointer to the GPIO definition
  * for the GPIO passed in.
  *
  * @param[in] gpio_name - the GPIO name, like BMC_POWER_UP
  *
  * @return cJSON* - pointer to the cJSON object or NULL
  *				  if not found.
  */
 cJSON* get_gpio_def(const char* gpio_name)
 {
 	if (gpio_json == NULL)
 	{
 		gpio_json = load_json();
 		if (gpio_json == NULL)
 		{
 			return NULL;
 		}
 	}

 	cJSON* gpio_defs = cJSON_GetObjectItem(gpio_json, "gpio_definitions");
 	g_assert(gpio_defs != NULL);

 	cJSON* def;
 	cJSON_ArrayForEach(def, gpio_defs)
 	{
 		cJSON* name = cJSON_GetObjectItem(def, "name");
 		g_assert(name != NULL);

 		if (strcmp(name->valuestring, gpio_name) == 0)
 		{
 			return def;
 		}
 	}
 	return NULL;
 }

 /**
  * Frees the gpio_json memory
  *
  * Can be called once when callers are done calling making calls
  * to gpio_init() so that the JSON only needs to be loaded once.
  */
 void gpio_inits_done()
 {
 	if (gpio_json != NULL)
 	{
 		cJSON_Delete(gpio_json);
 		gpio_json = NULL;
 	}
 }

 /**
  * Fills in the dev, direction, and num elements in
  * the GPIO structure.
  *
  * @param gpio - the GPIO structure to fill in
  *
  * @return GPIO_OK if successful
  */
 int gpio_get_params(GPIO* gpio)
 {
 	gpio->dev = g_strdup(GPIO_BASE_PATH);

 	const cJSON* def = get_gpio_def(gpio->name);
 	if (def == NULL)
 	{
 		fprintf(stderr, "Unable to find GPIO %s in the JSON\n",
 				gpio->name);
 		return GPIO_LOOKUP_ERROR;
 	}

 	const cJSON* dir = cJSON_GetObjectItem(def, "direction");
 	g_assert(dir != NULL);
 	gpio->direction = g_strdup(dir->valuestring);

 	/* Must use either 'num', like 87, or 'pin', like "A5" */
 	const cJSON* num = cJSON_GetObjectItem(def, "num");
 	if ((num != NULL) && cJSON_IsNumber(num))
 	{
 		gpio->num = num->valueint;
 	}
 	else
 	{
 		const cJSON* pin = cJSON_GetObjectItem(def, "pin");
 		g_assert(pin != NULL);

 		gpio->num = convert_gpio_to_num(pin->valuestring);
 		if (gpio->num < 0)
 		{
 			return GPIO_LOOKUP_ERROR;
 		}
 	}
 	// TODO: For the purposes of skeleton and the projects that use it,
 	// it should be safe to assume this will always be 0. Eventually skeleton
 	// should be going away, but if the need arises before then this may need
 	// to be updated to handle non-zero cases.
 	gpio->chip_id = 0;
 	return GPIO_OK;
 }

 int gpio_open(GPIO* gpio, uint8_t default_value)
 {
 	g_assert (gpio != NULL);

 	char buf[255];
 	sprintf(buf, "/dev/gpiochip%d", gpio->chip_id);
 	gpio->fd = open(buf, 0);
 	if (gpio->fd == -1)
 	{
 		return GPIO_OPEN_ERROR;
 	}

 	struct gpiohandle_request req;
 	memset(&req, 0, sizeof(req));
 	strncpy(req.consumer_label, "skeleton-gpio",  sizeof(req.consumer_label));

 	// open gpio for writing or reading
 	if (gpio->direction == NULL)
 	{
 		gpio_close(gpio);
 		return GPIO_OPEN_ERROR;
 	}
 	req.flags = (strcmp(gpio->direction,"in") == 0) ? GPIOHANDLE_REQUEST_INPUT
 								: GPIOHANDLE_REQUEST_OUTPUT;

 	req.lineoffsets[0] = gpio->num;
 	req.lines = 1;

 	if (strcmp(gpio->direction,"out") == 0)
 	{
 		req.default_values[0] = default_value;
 	}

 	int rc = ioctl(gpio->fd, GPIO_GET_LINEHANDLE_IOCTL, &req);
 	if (rc < 0)
 	{
 		gpio_close(gpio);
 		return GPIO_OPEN_ERROR;
 	}
 	gpio_close(gpio);
 	gpio->fd = req.fd;

 	return GPIO_OK;
 }

 void gpio_close(GPIO* gpio)
 {
 	if(gpio->fd < 0)
 		return;

 	close(gpio->fd);
 	gpio->fd = -1;
 }
	#define _GNU_SOURCE

	#include <stdint.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <fcntl.h>
	#include <unistd.h>
	#include <argp.h>
	#include <sys/stat.h>
	#include <sys/mman.h>
	#include <dirent.h>
	#include "openbmc_intf.h"
	#include "gpio.h"
	#include "gpio_json.h"

	#include <sys/ioctl.h>
	#include <linux/gpio.h>

	#define GPIO_PORT_OFFSET 8
	#define GPIO_BASE_PATH "/sys/class/gpio"

	cJSON* gpio_json = NULL;

	int gpio_write(GPIO* gpio, uint8_t value)
	{
	g_assert (gpio != NULL);
	struct gpiohandle_data data;
	memset(&data, 0, sizeof(data));
	data.values[0] = value;

	if (gpio->fd <= 0)
	{
	return GPIO_ERROR;
	}

	if (ioctl(gpio->fd, GPIOHANDLE_SET_LINE_VALUES_IOCTL, &data) < 0)
	{
	return GPIO_WRITE_ERROR;
	}

	return GPIO_OK;
	}

	int gpio_read(GPIO* gpio, uint8_t *value)
	{
	g_assert (gpio != NULL);
	struct gpiohandle_data data;
	memset(&data, 0, sizeof(data));

	if (gpio->fd <= 0)
	{
	return GPIO_ERROR;
	}

	if (ioctl(gpio->fd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, &data) < 0)
	{
	return GPIO_READ_ERROR;
	}

	*value = data.values[0];

	return GPIO_OK;
	}

	/**
	* Determine the GPIO base number for the system. It is found in
	* the 'base' file in the /sys/class/gpio/gpiochipX/ directory where the
	* /sys/class/gpio/gpiochipX/label file has a '1e780000.gpio' in it.
	*
	* Note: This method is ASPEED specific. Could add support for
	* additional SOCs in the future.
	*
	* @return int - the GPIO base number, or < 0 if not found
	*/
	int get_gpio_base()
	{
	int gpio_base = -1;

	DIR* dir = opendir(GPIO_BASE_PATH);
	if (dir == NULL)
	{
	fprintf(stderr, "Unable to open directory %s\n",
	GPIO_BASE_PATH);
	return -1;
	}

	struct dirent* entry;
	while ((entry = readdir(dir)) != NULL)
	{
	/* Look in the gpiochip<X> directories for a file called 'label' */
	/* that contains '1e780000.gpio', then in that directory read */
	/* the GPIO base out of the 'base' file. */

	if (strncmp(entry->d_name, "gpiochip", 8) != 0)
	{
	continue;
	}

	gboolean is_bmc = FALSE;
	char* label_name;
	asprintf(&label_name, "%s/%s/label",
	GPIO_BASE_PATH, entry->d_name);

	FILE* fd = fopen(label_name, "r");
	free(label_name);

	if (!fd)
	{
	continue;
	}

	char label[14];
	if (fgets(label, 14, fd) != NULL)
	{
	if (strcmp(label, "1e780000.gpio") == 0)
	{
	is_bmc = TRUE;
	}
	}
	fclose(fd);

	if (!is_bmc)
	{
	continue;
	}

	char* base_name;
	asprintf(&base_name, "%s/%s/base",
	GPIO_BASE_PATH, entry->d_name);

	fd = fopen(base_name, "r");
	free(base_name);

	if (!fd)
	{
	continue;
	}

	if (fscanf(fd, "%d", &gpio_base) != 1)
	{
	gpio_base = -1;
	}
	fclose(fd);

	/* We found the right file. No need to continue. */
	break;
	}
	closedir(dir);

	if (gpio_base == -1)
	{
	fprintf(stderr, "Could not find GPIO base\n");
	}

	return gpio_base;
	}

	/**
	* Converts the GPIO port/offset nomenclature value
	* to a number. Supports the ASPEED method where
	* num = base + (port * 8) + offset, and the port is an
	* A-Z character that converts to 0 to 25. The base
	* is obtained form the hardware.
	*
	* For example: "A5" -> 5, "Z7" -> 207
	*
	* @param[in] gpio - the GPIO name
	*
	* @return int - the GPIO number or < 0 if not found
	*/
	int convert_gpio_to_num(const char* gpio)
	{
	size_t len = strlen(gpio);
	if (len < 2)
	{
	fprintf(stderr, "Invalid GPIO name %s\n", gpio);
	return -1;
	}

	/* Read the offset from the last character */
	if (!isdigit(gpio[len-1]))
	{
	fprintf(stderr, "Invalid GPIO offset in GPIO %s\n", gpio);
	return -1;
	}

	int offset = gpio[len-1] - '0';

	/* Read the port from the second to last character */
	if (!isalpha(gpio[len-2]))
	{
	fprintf(stderr, "Invalid GPIO port in GPIO %s\n", gpio);
	return -1;
	}
	int port = toupper(gpio[len-2]) - 'A';

	/* Check for a 2 character port, like AA */
	if ((len == 3) && isalpha(gpio[len-3]))
	{
	port += 26 * (toupper(gpio[len-3]) - 'A' + 1);
	}

	return (port * GPIO_PORT_OFFSET) + offset;
	}

	/**
	* Returns the cJSON pointer to the GPIO definition
	* for the GPIO passed in.
	*
	* @param[in] gpio_name - the GPIO name, like BMC_POWER_UP
	*
	* @return cJSON* - pointer to the cJSON object or NULL
	* if not found.
	*/
	cJSON* get_gpio_def(const char* gpio_name)
	{
	if (gpio_json == NULL)
	{
	gpio_json = load_json();
	if (gpio_json == NULL)
	{
	return NULL;
	}
	}

	cJSON* gpio_defs = cJSON_GetObjectItem(gpio_json, "gpio_definitions");
	g_assert(gpio_defs != NULL);

	cJSON* def;
	cJSON_ArrayForEach(def, gpio_defs)
	{
	cJSON* name = cJSON_GetObjectItem(def, "name");
	g_assert(name != NULL);

	if (strcmp(name->valuestring, gpio_name) == 0)
	{
	return def;
	}
	}
	return NULL;
	}

	/**
	* Frees the gpio_json memory
	*
	* Can be called once when callers are done calling making calls
	* to gpio_init() so that the JSON only needs to be loaded once.
	*/
	void gpio_inits_done()
	{
	if (gpio_json != NULL)
	{
	cJSON_Delete(gpio_json);
	gpio_json = NULL;
	}
	}

	/**
	* Fills in the dev, direction, and num elements in
	* the GPIO structure.
	*
	* @param gpio - the GPIO structure to fill in
	*
	* @return GPIO_OK if successful
	*/
	int gpio_get_params(GPIO* gpio)
	{
	gpio->dev = g_strdup(GPIO_BASE_PATH);

	const cJSON* def = get_gpio_def(gpio->name);
	if (def == NULL)
	{
	fprintf(stderr, "Unable to find GPIO %s in the JSON\n",
	gpio->name);
	return GPIO_LOOKUP_ERROR;
	}

	const cJSON* dir = cJSON_GetObjectItem(def, "direction");
	g_assert(dir != NULL);
	gpio->direction = g_strdup(dir->valuestring);

	/* Must use either 'num', like 87, or 'pin', like "A5" */
	const cJSON* num = cJSON_GetObjectItem(def, "num");
	if ((num != NULL) && cJSON_IsNumber(num))
	{
	gpio->num = num->valueint;
	}
	else
	{
	const cJSON* pin = cJSON_GetObjectItem(def, "pin");
	g_assert(pin != NULL);

	gpio->num = convert_gpio_to_num(pin->valuestring);
	if (gpio->num < 0)
	{
	return GPIO_LOOKUP_ERROR;
	}
	}
	// TODO: For the purposes of skeleton and the projects that use it,
	// it should be safe to assume this will always be 0. Eventually skeleton
	// should be going away, but if the need arises before then this may need
	// to be updated to handle non-zero cases.
	gpio->chip_id = 0;
	return GPIO_OK;
	}

	int gpio_open(GPIO* gpio, uint8_t default_value)
	{
	g_assert (gpio != NULL);

	char buf[255];
	sprintf(buf, "/dev/gpiochip%d", gpio->chip_id);
	gpio->fd = open(buf, 0);
	if (gpio->fd == -1)
	{
	return GPIO_OPEN_ERROR;
	}

	struct gpiohandle_request req;
	memset(&req, 0, sizeof(req));
	strncpy(req.consumer_label, "skeleton-gpio", sizeof(req.consumer_label));

	// open gpio for writing or reading
	if (gpio->direction == NULL)
	{
	gpio_close(gpio);
	return GPIO_OPEN_ERROR;
	}
	req.flags = (strcmp(gpio->direction,"in") == 0) ? GPIOHANDLE_REQUEST_INPUT
	: GPIOHANDLE_REQUEST_OUTPUT;

	req.lineoffsets[0] = gpio->num;
	req.lines = 1;

	if (strcmp(gpio->direction,"out") == 0)
	{
	req.default_values[0] = default_value;
	}

	int rc = ioctl(gpio->fd, GPIO_GET_LINEHANDLE_IOCTL, &req);
	if (rc < 0)
	{
	gpio_close(gpio);
	return GPIO_OPEN_ERROR;
	}
	gpio_close(gpio);
	gpio->fd = req.fd;

	return GPIO_OK;
	}

	void gpio_close(GPIO* gpio)
	{
	if(gpio->fd < 0)
	return;

	close(gpio->fd);
	gpio->fd = -1;
	}