devices: add control io operation a.k.a. ioctl

JIRA: RTOS-848

devices/devs.c

@@ -140,6 +140,16 @@ int devs_map(unsigned int major, unsigned int minor, addr_t addr, size_t sz, int
 }
 
 
+int devs_control(unsigned int major, unsigned int minor, int cmd, void *args)
+{
+	const dev_ops_t *ops = devs_ops(major, minor);
+
+	return ((ops != NULL) && (ops->control != NULL)) ?
+		ops->control(minor, cmd, args) :
+		-ENOSYS;
+}
+
+
 void devs_done(void)
 {
 	const dev_t *dev;

devices/devs.h

@@ -38,6 +38,7 @@ enum { dev_isMappable = 0, dev_isNotMappable };
 typedef struct {
 	int (*sync)(unsigned int minor);
 	int (*map)(unsigned int minor, addr_t addr, size_t sz, int mode, addr_t memaddr, size_t memsz, int memmode, addr_t *a);
+	int (*control)(unsigned int minor, int cmd, void *args);
 	ssize_t (*read)(unsigned int minor, addr_t offs, void *buff, size_t len, time_t timeout);
 	ssize_t (*write)(unsigned int minor, addr_t offs, const void *buff, size_t len);
 	ssize_t (*erase)(unsigned int minor, addr_t offs, size_t len, unsigned int flags);
@@ -74,6 +75,10 @@ extern int devs_sync(unsigned int major, unsigned int minor);
 extern int devs_map(unsigned int major, unsigned int minor, addr_t addr, size_t sz, int mode, addr_t memaddr, size_t memsz, int memmode, addr_t *a);
 
 
+/* Control and manipulate the underlying device functions, parameters */
+extern int devs_control(unsigned int major, unsigned int minor, int cmd, void *args);
+
+
 /* Read data from device */
 extern ssize_t devs_read(unsigned int major, unsigned int minor, addr_t offs, void *buff, size_t len, time_t timeout);