Feather-Trace: add generic ftdev device driver

This patch adds the ftdev device driver, which is used to export
samples collected with Feather-Trace to userspace.

1 files changed, 58 insertions, 0 deletions

diff --git a/include/litmus/ftdev.h b/include/litmus/ftdev.h
new file mode 100644
index 000000000000..a566b0b6ae05
--- /dev/null
+++ b/include/litmus/ftdev.h
@@ -0,0 +1,58 @@
+#ifndef _LITMUS_FTDEV_H_
+#define _LITMUS_FTDEV_H_
+
+#include <litmus/feather_trace.h>
+#include <litmus/feather_buffer.h>
+#include <linux/mutex.h>
+#include <linux/cdev.h>
+
+#define FTDEV_ENABLE_CMD        0
+#define FTDEV_DISABLE_CMD       1
+#define FTDEV_CALIBRATE         0x1410
+
+struct ftdev;
+
+/* return 0 if buffer can be opened, otherwise -$REASON */
+typedef int  (*ftdev_can_open_t)(struct ftdev* dev, unsigned int buf_no);
+/* return 0 on success, otherwise -$REASON */
+typedef int  (*ftdev_alloc_t)(struct ftdev* dev, unsigned int buf_no);
+typedef void (*ftdev_free_t)(struct ftdev* dev, unsigned int buf_no);
+typedef long (*ftdev_calibrate_t)(struct ftdev* dev, unsigned int buf_no, unsigned long user_arg);
+/* Let devices handle writes from userspace. No synchronization provided. */
+typedef ssize_t (*ftdev_write_t)(struct ft_buffer* buf, size_t len, const char __user *from);
+
+struct ftdev_event;
+
+struct ftdev_minor {
+        struct ft_buffer*       buf;
+        unsigned int            readers;
+        struct mutex            lock;
+        /* FIXME: filter for authorized events */
+        struct ftdev_event*     events;
+        struct device*          device;
+        struct ftdev*           ftdev;
+};
+
+struct ftdev {
+        dev_t                   major;
+        struct cdev             cdev;
+        struct class*           class;
+        const char*             name;
+        struct ftdev_minor*     minor;
+        unsigned int            minor_cnt;
+        ftdev_alloc_t           alloc;
+        ftdev_free_t            free;
+        ftdev_can_open_t        can_open;
+        ftdev_write_t           write;
+        ftdev_calibrate_t       calibrate;
+};
+
+struct ft_buffer* alloc_ft_buffer(unsigned int count, size_t size);
+void free_ft_buffer(struct ft_buffer* buf);
+
+int ftdev_init( struct ftdev* ftdev, struct module* owner,
+                const int minor_cnt, const char* name);
+void ftdev_exit(struct ftdev* ftdev);
+int register_ftdev(struct ftdev* ftdev);
+
+#endif