Remove USBH_malloc/free and UsbHost wrapper for it

vorakl · Nov 13, 2022 · 4dc3400 · 4dc3400
1 parent f438c7e
commit 4dc3400
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Showing 4 changed files with 15 additions and 32 deletions.
diff --git a/examples/usb_midi_audio_host/usbh_conf.cc b/examples/usb_midi_audio_host/usbh_conf.cc
@@ -61,20 +61,6 @@ void HAL_HCD_MspDeInit(HCD_HandleTypeDef *hpcd)
 	}
 }
 
-void *USBH_malloc(size_t sz)
-{
-	static MidiStreamingHandle _mem;
-
-	if (sz == sizeof(MidiStreamingHandle))
-		return &_mem;
-
-	return NULL;
-}
-
-void USBH_free(void *){
-	// nothing, we're using static allocation
-};
-
 /*******************************************************************************
 					   LL Driver Callbacks (HCD -> USB Host Library)
 *******************************************************************************/

diff --git a/examples/usb_midi_audio_host/usbh_conf.h b/examples/usb_midi_audio_host/usbh_conf.h
@@ -61,8 +61,8 @@ extern "C" {
  */
 
 /* Memory management macros */
-void *USBH_malloc(size_t sz);
-void USBH_free(void *ptr);
+// void *USBH_malloc(size_t sz);
+// void USBH_free(void *ptr);
 
 #define USBH_memset memset
 #define USBH_memcpy memcpy

diff --git a/examples/usb_midi_audio_host/usbh_host.hh b/examples/usb_midi_audio_host/usbh_host.hh
@@ -14,8 +14,8 @@ enum class EndPointType : uint8_t {
 	Intr = USB_EP_TYPE_INTR,
 };
 
-// Wrapper for USBH_HandleTypeDef
-// That adds helper funcs for common operations
+// Stateless wrapper for USBH_HandleTypeDef*
+// That adds helper funcs for common operations in C functions that have a phost parameter
 class USBHostHandle {
 public:
 	USBH_HandleTypeDef *phost;
@@ -24,6 +24,9 @@ public:
 		: phost{phost}
 	{}
 
+	// Returns the user data of the active class, cast to whatever type you're expecting.
+	// Checks all the pointers before dereferencing them.
+	// Returns nullptr if it fails
 	template<typename HandleType>
 	HandleType *get_class_handle()
 	{
@@ -37,11 +40,14 @@ public:
 		return nullptr;
 	}
 
+	// Returns true if the endpoint specified by the interface index and endpoint index is an IN EP
 	bool is_in_ep(uint8_t interface, uint8_t ep_index)
 	{
 		auto addr = phost->device.CfgDesc.Itf_Desc[interface].Ep_Desc[ep_index].bEndpointAddress;
 		return (addr & 0x80U);
 	}
+
+	// Returns true if the endpoint specified by the interface index and endpoint index is an OUT EP
 	bool is_out_ep(uint8_t interface, uint8_t ep_index) { return !is_in_ep(interface, ep_index); }
 
 	void link_endpoint_pipe(EndPoint &ep, uint8_t interface, uint8_t ep_index)
@@ -74,16 +80,3 @@ public:
 		}
 	}
 };
-
-// Create a new, zeroed handle
-// Uses the user-defined USBH_malloc and USBH_memset
-// so that we can inter-operate with other classes from the STM32 Host Library
-template<typename HandleType>
-HandleType *new_usbh_handle()
-{
-	auto handle = static_cast<HandleType *>(USBH_malloc(sizeof(HandleType)));
-	if (handle)
-		USBH_memset(handle, 0, sizeof(HandleType));
-
-	return handle;
-}
diff --git a/examples/usb_midi_audio_host/usbh_midi.cc b/examples/usb_midi_audio_host/usbh_midi.cc
@@ -52,7 +52,11 @@ USBH_StatusTypeDef USBH_MIDI_InterfaceInit(USBH_HandleTypeDef *phost)
 	USBH_StatusTypeDef status;
 	uint8_t interface;
 
-	// phost->pActiveClass->pData = new_usbh_handle<MidiStreamingHandle>();
+	// In most STM Host Lib Classes, we USBH_malloc() a class handle here.
+	// But in this class, we already specified it by passing it in the pData field
+	// of the USBH_ClassTypeDef struct passed to USBH_RegisterClass
+	// This allows the app to own the class handle, managing its memory as it likes
+	// without needing dynamic memory or static/globals/singletons
 	if (phost->pActiveClass->pData == nullptr) {
 		USBH_DbgLog("Cannot allocate memory for CDC Handle");
 		return USBH_FAIL;