usb_cdcacm: Add hook system.

Provide hooks so users can reach into the CDC ACM callbacks with their
own code. We'll use this to move the bootloader reset signals to
Wirish.

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>

2 files changed, 44 insertions, 0 deletions

diff --git a/libmaple/include/libmaple/usb_cdcacm.h b/libmaple/include/libmaple/usb_cdcacm.h
index 85b4f5e..3b15d48 100644
--- a/libmaple/include/libmaple/usb_cdcacm.h
+++ b/libmaple/include/libmaple/usb_cdcacm.h
@@ -94,6 +94,19 @@ uint16 usb_cdcacm_get_pending(void);
 uint8 usb_cdcacm_get_dtr(void);
 uint8 usb_cdcacm_get_rts(void);
 
+/*
+ * Hack: hooks for bootloader reset signalling
+ */
+
+#define USB_CDCACM_HOOK_RX 0x1
+#define USB_CDCACM_HOOK_IFACE_SETUP 0x2
+
+void usb_cdcacm_set_hooks(unsigned hook_flags, void (*hook)(unsigned, void*));
+
+static __always_inline void usb_cdcacm_remove_hooks(unsigned hook_flags) {
+    usb_cdcacm_set_hooks(hook_flags, 0);
+}
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/libmaple/usb/stm32f1/usb_cdcacm.c b/libmaple/usb/stm32f1/usb_cdcacm.c
index 75bbc4f..ee3c8e3 100644
--- a/libmaple/usb/stm32f1/usb_cdcacm.c
+++ b/libmaple/usb/stm32f1/usb_cdcacm.c
@@ -354,6 +354,22 @@ USER_STANDARD_REQUESTS User_Standard_Requests = {
 };
 
 /*
+ * User hooks
+ */
+
+static void (*rx_hook)(unsigned, void*) = 0;
+static void (*iface_setup_hook)(unsigned, void*) = 0;
+
+void usb_cdcacm_set_hooks(unsigned hook_flags, void (*hook)(unsigned, void*)) {
+    if (hook_flags & USB_CDCACM_HOOK_RX) {
+        rx_hook = hook;
+    }
+    if (hook_flags & USB_CDCACM_HOOK_IFACE_SETUP) {
+        iface_setup_hook = hook;
+    }
+}
+
+/*
  * CDC ACM interface
  */
 
@@ -522,6 +538,10 @@ static void vcomDataRxCb(void) {
     }
 
     usb_copy_from_pma(vcomBufferRx, newBytes, USB_CDCACM_RX_ADDR);
+
+    if (rx_hook) {
+        rx_hook(USB_CDCACM_HOOK_RX, 0);
+    }
 }
 
 static uint8* vcomGetSetLineCoding(uint16 length) {
@@ -607,6 +627,12 @@ static RESULT usbDataSetup(uint8 request) {
     CopyRoutine = NULL;
 
     if (Type_Recipient == (CLASS_REQUEST | INTERFACE_RECIPIENT)) {
+        /* Call the user hook first. */
+        if (iface_setup_hook) {
+            uint8 req_copy = request;
+            iface_setup_hook(USB_CDCACM_HOOK_IFACE_SETUP, &req_copy);
+        }
+
         switch (request) {
         case (USB_CDCACM_GET_LINE_CODING):
             CopyRoutine = vcomGetSetLineCoding;
@@ -636,6 +662,11 @@ static RESULT usbNoDataSetup(uint8 request) {
 
     /* we support set com feature but dont handle it */
     if (Type_Recipient == (CLASS_REQUEST | INTERFACE_RECIPIENT)) {
+        /* Call the user hook first. */
+        if (iface_setup_hook) {
+            uint8 req_copy = request;
+            iface_setup_hook(USB_CDCACM_HOOK_IFACE_SETUP, &req_copy);
+        }
 
         switch (request) {
         case (USB_CDCACM_SET_COMM_FEATURE):