serialqueue: Add "fast reader" support

Add ability to run C code directly from the low-level socket reading
thread.  This enables host based low-latency handlers.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 13 insertions, 0 deletions

diff --git a/klippy/chelper/serialqueue.h b/klippy/chelper/serialqueue.h
index 62e70403..9e66e7f5 100644
--- a/klippy/chelper/serialqueue.h
+++ b/klippy/chelper/serialqueue.h
@@ -1,12 +1,23 @@
 #ifndef SERIALQUEUE_H
 #define SERIALQUEUE_H
 
+#include <stdint.h> // uint8_t
 #include "list.h" // struct list_head
 #include "msgblock.h" // MESSAGE_MAX
 
 #define MAX_CLOCK 0x7fffffffffffffffLL
 #define BACKGROUND_PRIORITY_CLOCK 0x7fffffff00000000LL
 
+struct fastreader;
+typedef void (*fastreader_cb)(struct fastreader *fr, uint8_t *data, int len);
+
+struct fastreader {
+    struct list_node node;
+    fastreader_cb func;
+    int prefix_len;
+    uint8_t prefix[MESSAGE_MAX];
+};
+
 struct pull_queue_message {
     uint8_t msg[MESSAGE_MAX];
     int len;
@@ -21,6 +32,8 @@ void serialqueue_exit(struct serialqueue *sq);
 void serialqueue_free(struct serialqueue *sq);
 struct command_queue *serialqueue_alloc_commandqueue(void);
 void serialqueue_free_commandqueue(struct command_queue *cq);
+void serialqueue_add_fastreader(struct serialqueue *sq, struct fastreader *fr);
+void serialqueue_rm_fastreader(struct serialqueue *sq, struct fastreader *fr);
 void serialqueue_send_batch(struct serialqueue *sq, struct command_queue *cq
                             , struct list_head *msgs);
 void serialqueue_send(struct serialqueue *sq, struct command_queue *cq