lib/params: add igt_params.c for module parameter access

We have generic helpers for sysfs access in igt_sysfs.c, but we also
have a number of module parameter access specific helpers scattered here
and there. Start gathering the latter into a file of its own.

For i915, the long-term goal is to migrate from module parameters to
device specific debugfs parameters. With all igt module param access
centralized in one place, we can make the transition much easier.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Reviewed-by: Petri Latvala <petri.latvala@intel.com>

1 files changed, 1 insertions, 142 deletions

diff --git a/lib/igt_aux.c b/lib/igt_aux.c
index ecab5d99..c55b2916 100644
--- a/lib/igt_aux.c
+++ b/lib/igt_aux.c
@@ -60,6 +60,7 @@
 #include "igt_aux.h"
 #include "igt_debugfs.h"
 #include "igt_gt.h"
+#include "igt_params.h"
 #include "igt_rand.h"
 #include "igt_sysfs.h"
 #include "config.h"
@@ -1116,148 +1117,6 @@ void igt_unlock_mem(void)
 	locked_mem = NULL;
 }
 
-
-#define MODULE_PARAM_DIR "/sys/module/i915/parameters/"
-#define PARAM_NAME_MAX_SZ 32
-#define PARAM_VALUE_MAX_SZ 16
-#define PARAM_FILE_PATH_MAX_SZ (strlen(MODULE_PARAM_DIR) + PARAM_NAME_MAX_SZ)
-
-struct module_param_data {
-	char name[PARAM_NAME_MAX_SZ];
-	char original_value[PARAM_VALUE_MAX_SZ];
-
-	struct module_param_data *next;
-};
-struct module_param_data *module_params = NULL;
-
-static void igt_module_param_exit_handler(int sig)
-{
-	const size_t dir_len = strlen(MODULE_PARAM_DIR);
-	char file_path[PARAM_FILE_PATH_MAX_SZ];
-	struct module_param_data *data;
-	int fd;
-
-	/* We don't need to assert string sizes on this function since they were
-	 * already checked before being stored on the lists. Besides,
-	 * igt_assert() is not AS-Safe. */
-	strcpy(file_path, MODULE_PARAM_DIR);
-
-	for (data = module_params; data != NULL; data = data->next) {
-		strcpy(file_path + dir_len, data->name);
-
-		fd = open(file_path, O_RDWR);
-		if (fd >= 0) {
-			int size = strlen (data->original_value);
-
-			if (size != write(fd, data->original_value, size)) {
-				const char msg[] = "WARNING: Module parameters "
-					"may not have been reset to their "
-					"original values\n";
-				assert(write(STDERR_FILENO, msg, sizeof(msg))
-				       == sizeof(msg));
-			}
-
-			close(fd);
-		}
-	}
-	/* free() is not AS-Safe, so we can't call it here. */
-}
-
-/**
- * igt_save_module_param:
- * @name: name of the i915.ko module parameter
- * @file_path: full sysfs file path for the parameter
- *
- * Reads the current value of an i915.ko module parameter, saves it on an array,
- * then installs an exit handler to restore it when the program exits.
- *
- * It is safe to call this function multiple times for the same parameter.
- *
- * Notice that this function is called by igt_set_module_param(), so that one -
- * or one of its wrappers - is the only function the test programs need to call.
- */
-static void igt_save_module_param(const char *name, const char *file_path)
-{
-	struct module_param_data *data;
-	size_t n;
-	int fd;
-
-	/* Check if this parameter is already saved. */
-	for (data = module_params; data != NULL; data = data->next)
-		if (strncmp(data->name, name, PARAM_NAME_MAX_SZ) == 0)
-			return;
-
-	if (!module_params)
-		igt_install_exit_handler(igt_module_param_exit_handler);
-
-	data = calloc(1, sizeof (*data));
-	igt_assert(data);
-
-	strncpy(data->name, name, PARAM_NAME_MAX_SZ - 1);
-
-	fd = open(file_path, O_RDONLY);
-	igt_assert(fd >= 0);
-
-	n = read(fd, data->original_value, PARAM_VALUE_MAX_SZ);
-	igt_assert_f(n > 0 && n < PARAM_VALUE_MAX_SZ,
-		     "Need to increase PARAM_VALUE_MAX_SZ\n");
-
-	igt_assert(close(fd) == 0);
-
-	data->next = module_params;
-	module_params = data;
-}
-
-/**
- * igt_set_module_param:
- * @name: i915.ko parameter name
- * @val: i915.ko parameter value
- *
- * This function sets the desired value for the given i915.ko parameter. It also
- * takes care of saving and restoring the values that were already set before
- * the test was run.
- *
- * Please consider using igt_set_module_param_int() for the integer and bool
- * parameters.
- */
-void igt_set_module_param(const char *name, const char *val)
-{
-	char file_path[PARAM_FILE_PATH_MAX_SZ];
-	size_t len = strlen(val);
-	int fd;
-
-	igt_assert_f(strlen(name) < PARAM_NAME_MAX_SZ,
-		     "Need to increase PARAM_NAME_MAX_SZ\n");
-	strcpy(file_path, MODULE_PARAM_DIR);
-	strcpy(file_path + strlen(MODULE_PARAM_DIR), name);
-
-	igt_save_module_param(name, file_path);
-
-	fd = open(file_path, O_RDWR);
-	igt_assert(write(fd, val, len) == len);
-	igt_assert(close(fd) == 0);
-}
-
-/**
- * igt_set_module_param_int:
- * @name: i915.ko parameter name
- * @val: i915.ko parameter value
- *
- * This is a wrapper for igt_set_module_param() that takes an integer instead of
- * a string. Please see igt_set_module_param().
- */
-void igt_set_module_param_int(const char *name, int val)
-{
-	char str[PARAM_VALUE_MAX_SZ];
-	int n;
-
-	n = snprintf(str, PARAM_VALUE_MAX_SZ, "%d\n", val);
-	igt_assert_f(n < PARAM_VALUE_MAX_SZ,
-		     "Need to increase PARAM_VALUE_MAX_SZ\n");
-
-	igt_set_module_param(name, str);
-}
-
 /**
  * igt_is_process_running:
  * @comm: Name of process in the form found in /proc/pid/comm (limited to 15