Synchronizing with my work copy.

cpu/arm/at91sam7s/Makefile.at91sam7s

@@ -190,4 +190,11 @@ ocd_reset:
 $(OBJECTDIR)/elfloader.o: 
 	echo -n >$@
 
+clean: clean_cpu
+
+.PHONY: clean_cpu
+
+clean_cpu:
+	-rm -rf $(BUILTSRCDIR)
+
 .PRECIOUS: %-nosyms.$(TARGET)

cpu/arm/at91sam7s/usb-arch.c

@@ -5,7 +5,7 @@
 #include <debug-uart.h>
 
 
-/* #define DEBUG  */
+/* #define DEBUG   */
 #ifdef DEBUG
 #define PRINTF(...) printf(__VA_ARGS__)
 #else
@@ -340,7 +340,7 @@ static unsigned int
 get_receive_capacity(USBBuffer *buffer)
 {
   unsigned int capacity = 0;
-  while(buffer && !(buffer->flags & (USB_BUFFER_IN| USB_BUFFER_SETUP))) {
+  while(buffer && !(buffer->flags & (USB_BUFFER_IN| USB_BUFFER_SETUP|USB_BUFFER_HALT))) {
     capacity += buffer->left;
     buffer = buffer->next;
   }
@@ -494,6 +494,16 @@ start_transmit(USBEndpoint *ep)
   if (!(ep_flags & USB_EP_FLAGS_ENABLED) || !buffer) return USB_WRITE_BLOCK;
   switch(ep_flags & USB_EP_FLAGS_TYPE_MASK) {
   case USB_EP_FLAGS_TYPE_BULK:
+    if (buffer->flags & USB_BUFFER_HALT) {
+      if (ep->status & 0x01) return USB_WRITE_BLOCK;
+      ep->status |= 0x01;
+      if (!(ep->flags & USB_EP_FLAGS_TRANSMITTING)) {
+	UDP_SET_EP_CTRL_FLAGS(&AT91C_UDP_CSR[hw_ep],
+			      AT91C_UDP_FORCESTALL, AT91C_UDP_FORCESTALL);
+	PRINTF("HALT IN\n");
+      }
+      return USB_WRITE_BLOCK;
+    }
   case USB_EP_FLAGS_TYPE_ISO:
     if (!(ep->flags & USB_EP_FLAGS_TRANSMITTING)) {
       if (AT91C_UDP_CSR[hw_ep] & AT91C_UDP_TXPKTRDY) return USB_WRITE_BLOCK;
@@ -518,8 +528,6 @@ start_transmit(USBEndpoint *ep)
     if (buffer->left == 0) {
       if (buffer->flags & USB_BUFFER_SHORT_END) {
 	if (len == 0) {
-	  /* Avoid endless loop */
-	  buffer->flags &= ~USB_BUFFER_SHORT_END;
 	  /* Send zero length packet. */
 	  break;
 	} else {
@@ -554,7 +562,19 @@ start_transfer(USBEndpoint *ep)
 {
   unsigned int hw_ep = EP_HW_NUM(ep->addr);
   int res;
-  while (ep->flags & USB_EP_FLAGS_RECV_PENDING) {
+  while (1) {
+    if (!(ep->addr & 0x80)) {
+      if (ep->buffer && (ep->buffer->flags & USB_BUFFER_HALT)) {
+	if (ep->status & 0x01) return ;
+	ep->status |= 0x01;
+	UDP_SET_EP_CTRL_FLAGS(&AT91C_UDP_CSR[EP_HW_NUM(ep->addr)],
+			      AT91C_UDP_FORCESTALL, AT91C_UDP_FORCESTALL);
+	PRINTF("HALT OUT\n");
+	*AT91C_UDP_IDR = 1<<hw_ep;
+	return;
+      }
+    }
+    if (!(ep->flags & USB_EP_FLAGS_RECV_PENDING)) break;
     res = handle_pending_receive(ep);
     if (res & USB_READ_NOTIFY) {
       notify_ep_process(ep, USB_EP_EVENT_NOTIFICATION);
@@ -609,7 +629,7 @@ start_transfer(USBEndpoint *ep)
   if (ep->buffer) {
     if (ep->buffer->flags & USB_BUFFER_IN) {
       res = start_transmit(ep);
-      if (res & USB_READ_NOTIFY) {
+      if (res & USB_WRITE_NOTIFY) {
 	notify_ep_process(ep, USB_EP_EVENT_NOTIFICATION);
       }
     } else {
@@ -658,6 +678,7 @@ usb_arch_transfer_complete(unsigned int hw_ep)
     if (ep->status & 0x01) {
       UDP_SET_EP_CTRL_FLAGS(&AT91C_UDP_CSR[hw_ep],
 			    AT91C_UDP_FORCESTALL, AT91C_UDP_FORCESTALL);
+      PRINTF("HALT IN\n");
     } else {
       start_transfer(ep);
     }
@@ -807,7 +828,16 @@ usb_arch_halt_endpoint(unsigned char ep_addr, int halt)
 			  0, AT91C_UDP_FORCESTALL);
     *AT91C_UDP_RSTEP = 1<<EP_HW_NUM(ep_addr);
     *AT91C_UDP_RSTEP = 0;
-	
+    
+    /* Release HALT buffer */
+    if (ep->buffer && (ep->buffer->flags & USB_BUFFER_HALT)) {
+      ep->buffer->flags &= ~USB_BUFFER_SUBMITTED;
+      if (ep->buffer->flags & USB_BUFFER_NOTIFY) {
+	notify_ep_process(ep,USB_EP_EVENT_NOTIFICATION);
+      }
+      ep->buffer = ep->buffer->next;
+    }
+    
     /* Restart transmission */
     start_transfer(&usb_endpoints[EP_INDEX(ep_addr)]);
   }

cpu/arm/common/dbg-io/dbg-printf.c

@@ -6,7 +6,7 @@
 static StrFormatResult
 write_str(void *user_data, const char *data, unsigned int len)
 {
-  dbg_send_bytes((unsigned char*)data, len);
+  if (len > 0) dbg_send_bytes((unsigned char*)data, len);
   return STRFORMAT_OK;
 }
 

cpu/arm/common/usb/Makefile.usb

@@ -4,6 +4,8 @@ ifeq (${wildcard $(BUILTSRCDIR)},)
   DUMMY := ${shell mkdir $(BUILTSRCDIR)}
 endif
 
+STRUCTGEN = structgen
+
 PROJECTDIRS += $(BUILTSRCDIR)
 
 USB_STRING_DESCRIPTORS ?= $(CONTIKI_CPU_ARM)/common/usb/cdc-acm/string-descriptors.xml
@@ -26,7 +28,7 @@ endif
 
 ifdef USB_MASS_STORAGE_CLASS
 CONTIKI_CPU_DIRS += ../common/usb/msc
-USB += usb-msc-bulk.c usb-rbc.c msc-descriptors.c msc-string-descriptors.c
+USB += usb-msc-bulk.c usb-rbc.c msc-descriptors-consts.c msc-descriptors.c 
 XMLDIRS += $(CONTIKI_CPU_ARM)/common/usb/msc
 endif
 
@@ -42,7 +44,17 @@ USB += usb-msc-bulk.c usb-streaming.c msc-scsi-transparent-descriptors.c msc-str
 XMLDIRS += $(CONTIKI_CPU_ARM)/common/usb/msc
 endif
 
+ifdef USB_MTP_CLASS
+CONTIKI_CPU_DIRS += ../common/usb/mtp
+USB += usb-mtp.c mtp-descriptors-consts.c mtp-descriptors.c
+STRUCTGENDIRS += $(CONTIKI_CPU_ARM)/common/usb/mtp
+endif
+
 vpath %.xml $(XMLDIRS)
+vpath %.gen.c $(STRUCTGENDIRS)
 
 %.c: %.xml
 	$(XSLTPROC) $(CONTIKI_CPU_ARM)/common/usb/string-descriptors.xslt $^ >$(BUILTSRCDIR)/$@
+
+%-consts.c: %.gen.c 
+	$(CPP) -I$(CFLAGS) $< | $(STRUCTGEN) --output $(BUILTSRCDIR)/$*-consts.c

cpu/arm/common/usb/descriptors.h

@@ -1,7 +1,9 @@
 #ifndef __DESCRIPTORS_H__RPFUB8O7OV__
 #define __DESCRIPTORS_H__RPFUB8O7OV__
 
+#ifndef STRUCTGEN
 #include "usb.h"
+#endif
 
 extern const struct usb_st_device_descriptor device_descriptor;
 extern const struct usb_st_configuration_descriptor const *configuration_head;

cpu/arm/common/usb/msc/usb-msc-bulk.c

@@ -5,7 +5,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#define DEBUG   
+#define DEBUG     
 
 #ifdef DEBUG
 #define PRINTF(...) printf(__VA_ARGS__)
@@ -65,13 +65,14 @@ usb_msc_send_data_buf_flags(const uint8_t *data, unsigned int len,
   }
   state.cmd_data_submitted += len;
   buf_free = NEXT_BUF(buf_free);
-/*   PRINTF("usb_msc_send_data: %d\n", len); */
+  /* PRINTF("usb_msc_send_data: %d\n", len); */
   if (flags & USB_MSC_DATA_SEND) {
     usb_submit_xmit_buffer(BULK_IN, &data_usb_buffer[buf_first]);
     buf_first = buf_free;
-/*     PRINTF("usb_msc_send_data: sent\n"); */
+    /* PRINTF("usb_msc_send_data: sent\n"); */
   } else if (flags & USB_MSC_DATA_LAST) {
     /* Cancel transmission */
+    PRINTF("Send last\n");
     buf_first = buf_free;
     process_poll(&usb_mass_bulk_process);
   }
@@ -89,7 +90,7 @@ usb_msc_receive_data_buf_flags(uint8_t *data, unsigned int len,
 {
   USBBuffer *buffer = &data_usb_buffer[buf_free];
   if (buffer->id != USB_BUFFER_ID_UNUSED) {
-    printf("Data IN buffer busy\n");
+    printf("Data OUT buffer busy\n");
     return;
   }
   buffer->flags = USB_BUFFER_NOTIFY | buf_flags;
@@ -363,6 +364,7 @@ PROCESS_THREAD(usb_mass_bulk_request_process, ev , data)
     uint8_t id = 0;
     /* Wait for any data to be sent */
     while (buf_submitted == buf_free) {
+      PRINTF("Wait data\n");
       PROCESS_WAIT_EVENT();
     }
 #if 0
@@ -379,7 +381,7 @@ PROCESS_THREAD(usb_mass_bulk_request_process, ev , data)
     }
     while (!(data_usb_buffer[buf_submitted].flags & USB_BUFFER_SUBMITTED)) {
       id = data_usb_buffer[buf_submitted].id;
-      /* PRINTF("id: %02x\n", id); */
+      /* PRINTF("id: %02x\n", id);  */
       if (id == USB_BUFFER_ID_UNUSED) break;
       state.cmd_data_transfered += buffer_lengths[buf_submitted];
       data_usb_buffer[buf_submitted].id = USB_BUFFER_ID_UNUSED;

cpu/arm/common/usb/msc/usb-msc-bulk.h

@@ -3,39 +3,10 @@
 
 #include <usb.h>
 #include <stdint.h>
+#include <msc/msc-defs.h>
 
-#define USB_MSC_BUFFERS 4
+#define USB_MSC_BUFFERS 16
 
-/*  Communication Class */
-/* Class code */
-#define MASS_STORAGE  0x08
-
-/* Interface subclass codes */
-#define MASS_RBC 0x01
-#define MASS_SFF_8020i 0x02
-#define MASS_MMC_2 0x02
-#define MASS_QIC_157 0x03
-#define MASS_UFI 0x04
-#define MASS_SFF_8070i 0x05
-#define MASS_SCSI_TRANSP 0x06
-
-/* Protocols */
-#define MASS_CBI_COMPLETION 0x00
-#define MASS_CBI_NO_COMPLETION 0x01
-#define MASS_BULK_ONLY 0x50
-
-/* Requests */
-#define MASS_BULK_RESET 0xff
-#define MASS_BULK_GET_MAX_LUN 0xfe
-
-#define MASS_BULK_CBW_SIGNATURE  0x43425355
-#define MASS_BULK_CSW_SIGNATURE  0x53425355
-
-#define MASS_BULK_CBW_FLAG_IN 0x80
-
-#define MASS_BULK_CSW_STATUS_PASSED 0x00
-#define MASS_BULK_CSW_STATUS_FAILED 0x01
-#define MASS_BULK_CSW_STATUS_PHASE_ERROR 0x02
 
 struct usb_msc_bulk_cbw
 {

cpu/arm/common/usb/string-descriptors.h

@@ -1,16 +1,23 @@
+#ifndef STRUCTGEN
 #include "usb.h"
+#endif
+#include <stdint.h>
+
 struct usb_st_string_language_map
 {
-  Uint16 lang_id;
+  uint16_t lang_id;
   const struct usb_st_string_descriptor * const *descriptors;
 };
 
 struct usb_st_string_languages
 {
-  Uchar num_lang;
+  uint8_t num_lang;
-  Uchar max_index;
+  uint8_t max_index;
   const struct usb_st_language_descriptor *lang_descr;
   const struct usb_st_string_language_map map[1];
 };
   
 extern const struct usb_st_string_languages * const string_languages;
+
+const uint8_t *
+usb_class_get_string_descriptor(uint16_t lang, uint8_t index);

cpu/arm/common/usb/usb-api.h

@@ -37,7 +37,7 @@ struct _USBBuffer
 
 /* HALT the endpoint at this point. Only valid for bulk and interrupt
    endpoints */
-#define USB_BUFFER_HALT 0x20
+#define USB_BUFFER_HALT 0x100
 
 /* Flags set by system */
 
@@ -78,6 +78,9 @@ struct USBRequestHandlerHook
 void
 usb_register_request_handler(struct USBRequestHandlerHook *hook);
 
+void
+usb_prepend_request_handler(struct USBRequestHandlerHook *hook);
+
 void
 usb_setup_bulk_endpoint(uint8_t addr);
 void

cpu/arm/common/usb/usb-core.c

@@ -8,7 +8,7 @@
 #include <descriptors.h>
 #include <string-descriptors.h>
 
-/* #define DEBUG   */
+#define DEBUG 
 #ifdef DEBUG
 #define PRINTF(...) printf(__VA_ARGS__)
 #else
@@ -25,8 +25,8 @@ static USBBuffer ctrl_buffer;
 #define STATUS_OUT_ID 4
 #define STATUS_IN_ID 5
 
-static unsigned short usb_device_status;
+static uint16_t usb_device_status;
-static unsigned char usb_configuration_value;
+static uint8_t usb_configuration_value;
 
 static struct USBRequestHandlerHook *usb_request_handler_hooks = NULL;
 
@@ -35,11 +35,6 @@ static const unsigned short zero_word = 0;
 
 static unsigned char usb_flags = 0;
 #define USB_FLAG_ADDRESS_PENDING 0x01
-#define USB_FLAG_RECEIVING_CTRL 0x04
-#define USB_FLAG_SEND_ZLP 0x08 /* If the last packet has max length,
-				  then it needs to be followed by a
-				  zero length packet to mark the
-				  end. */
 
 static struct process *global_user_event_pocess = NULL;
 static unsigned int global_user_events = 0;
@@ -74,6 +69,9 @@ usb_send_ctrl_response(const uint8_t *data, unsigned int len)
     len = usb_setup_buffer.wLength;	/* Truncate if too long */
   }
   ctrl_buffer.flags = USB_BUFFER_NOTIFY | USB_BUFFER_IN;
+  if (len < usb_setup_buffer.wLength) {
+    ctrl_buffer.flags |= USB_BUFFER_SHORT_END;
+  }
   ctrl_buffer.next = NULL;
   ctrl_buffer.data = (uint8_t*)data;
   ctrl_buffer.left = len;
@@ -81,9 +79,12 @@ usb_send_ctrl_response(const uint8_t *data, unsigned int len)
   usb_submit_xmit_buffer(0,&ctrl_buffer);
 }
 
+static uint8_t error_stall = 0;
+
 void
 usb_error_stall()
 {
+  error_stall = 1;
   usb_arch_control_stall(0);
 }
 
@@ -137,12 +138,13 @@ get_device_descriptor()
 static void
 get_string_descriptor()
 {
+#if OLD_STRING_DESCR
   if (LOW_BYTE(usb_setup_buffer.wValue) == 0) {
     usb_send_ctrl_response((const unsigned char*)string_languages->lang_descr,
 			   string_languages->lang_descr->bLength);
   } else {
-    unsigned char l;
     const struct usb_st_string_descriptor *descriptor;
+    unsigned char l;
     const struct usb_st_string_descriptor * const *table;
     const struct usb_st_string_language_map *map;
     if (LOW_BYTE(usb_setup_buffer.wValue) > string_languages->max_index) {
@@ -165,6 +167,18 @@ get_string_descriptor()
     usb_send_ctrl_response((const unsigned char*)descriptor,
 			   descriptor->bLength);
   }
+#else
+  const struct usb_st_string_descriptor *descriptor;
+  descriptor = (struct usb_st_string_descriptor*)
+    usb_class_get_string_descriptor(usb_setup_buffer.wIndex,
+				    LOW_BYTE(usb_setup_buffer.wValue));
+  if (!descriptor) {
+    usb_error_stall();
+    return;
+  }
+  usb_send_ctrl_response((const unsigned char*)descriptor,
+			   descriptor->bLength);
+#endif
 }
 
 static void
@@ -478,6 +492,11 @@ PROCESS_THREAD(usb_process, ev , data)
 		     usb_setup_buffer.bmRequestType, usb_setup_buffer.bRequest,
 		     usb_setup_buffer.wValue, usb_setup_buffer.wIndex,
 		     usb_setup_buffer.wLength);
+	    }
+	    /* Check if any handler stalled the pipe, if so prepare for
+	       next setup */
+	    if (error_stall) {
+	      error_stall = 0;
 	      submit_setup();
 	    }
 	  } else {
@@ -542,6 +561,13 @@ usb_register_request_handler(struct USBRequestHandlerHook *hook)
   hook->next = NULL;
 }
 
+void
+usb_prepend_request_handler(struct USBRequestHandlerHook *hook)
+{
+  hook->next = usb_request_handler_hooks;
+  usb_request_handler_hooks = hook;
+}
+
 
 unsigned int
 usb_get_current_configuration(void)

cpu/arm/stm32f103/gpio.h

@@ -66,4 +66,64 @@ _GPIO_OUTPUT_SPEED_##speed(_GPIO_CONF_BIT_REG_##bit(GPIO_,_MODE##bit##_1),\
 #define AFIO_REMAP(mask,value) \
 MODIFY_REG(AFIO->MAPR, AFIO_MAPR_SWJ_CFG | mask, AFIO_MAPR_SWJ_CFG_VALUE | value);
 
+#define GPIO_CM0  0x000000000000000fLL
+#define GPIO_CM1  0x00000000000000f0LL
+#define GPIO_CM2  0x0000000000000f00LL
+#define GPIO_CM3  0x000000000000f000LL
+#define GPIO_CM4  0x00000000000f0000LL
+#define GPIO_CM5  0x0000000000f00000LL
+#define GPIO_CM6  0x000000000f000000LL
+#define GPIO_CM7  0x00000000f0000000LL
+#define GPIO_CM8  0x0000000f00000000LL
+#define GPIO_CM9  0x000000f000000000LL
+#define GPIO_CM10 0x00000f0000000000LL
+#define GPIO_CM11 0x0000f00000000000LL
+#define GPIO_CM12 0x000f000000000000LL
+#define GPIO_CM13 0x00f0000000000000LL
+#define GPIO_CM14 0x0f00000000000000LL
+#define GPIO_CM15 0xf000000000000000LL
+
+#define _GPIO_CONF_INPUT_MASK(port, mask , mode)	\
+  MODIFY_REG(GPIO##port ->CRH,((mask)>>32), (mode & ((mask)>>32)));	\
+  MODIFY_REG(GPIO##port ->CRL,((mask)&0xffffffff), (mode & ((mask)&0xffffffff)))
+
+#define GPIO_CONF_INPUT_ANALOG(port, mask) \
+  _GPIO_CONF_INPUT_MASK(port, mask, 0x00000000)
+
+#define GPIO_CONF_INPUT_FLOATING(port, mask) \
+  _GPIO_CONF_INPUT_MASK(port, mask, 0x44444444)
+
+#define GPIO_CONF_INPUT_PU_PD(port, mask) \
+  _GPIO_CONF_INPUT_MASK(port, mask, 0x88888888)
+
+#define GPIO_CONF_OUTPUT_PUSH_PULL_50(port, mask) \
+  _GPIO_CONF_INPUT_MASK(port, mask, 0x22222222)
+#define GPIO_CONF_OUTPUT_PUSH_PULL_10(port, mask) \
+  _GPIO_CONF_INPUT_MASK(port, mask, 0x33333333)
+#define GPIO_CONF_OUTPUT_PUSH_PULL_2(port, mask) \
+  _GPIO_CONF_INPUT_MASK(port, mask, 0x11111111)
+
+#define GPIO_CONF_OUTPUT_OPEN_DRAIN_50(port, mask) \
+  _GPIO_CONF_INPUT_MASK(port, mask, 0x77777777)
+#define GPIO_CONF_OUTPUT_OPEN_DRAIN_10(port, mask) \
+  _GPIO_CONF_INPUT_MASK(port, mask, 0x55555555)
+#define GPIO_CONF_OUTPUT_OPEN_DRAIN_2(port, mask) \
+  _GPIO_CONF_INPUT_MASK(port, mask, 0x66666666)
+
+#define GPIO_CONF_OUTPUT_ALT_PUSH_PULL_50(port, mask) \
+  _GPIO_CONF_INPUT_MASK(port, mask, 0xbbbbbbbb)
+#define GPIO_CONF_OUTPUT_ALT_PUSH_PULL_10(port, mask) \
+  _GPIO_CONF_INPUT_MASK(port, mask, 0x99999999)
+#define GPIO_CONF_OUTPUT_ALT_PUSH_PULL_2(port, mask) \
+  _GPIO_CONF_INPUT_MASK(port, mask, 0xaaaaaaaa)
+
+#define GPIO_CONF_OUTPUT_ALT_OPEN_DRAIN_50(port, mask) \
+  _GPIO_CONF_INPUT_MASK(port, mask, 0xffffffff)
+#define GPIO_CONF_OUTPUT_ALT_OPEN_DRAIN_10(port, mask) \
+  _GPIO_CONF_INPUT_MASK(port, mask, 0xdddddddd)
+#define GPIO_CONF_OUTPUT_ALT_OPEN_DRAIN_2(port, mask) \
+  _GPIO_CONF_INPUT_MASK(port, mask, 0xeeeeeeee)
+
+
+
 #endif /* __GPIO_H__LK7NAD1HN8__ */

cpu/arm/stm32f103/stm32f10x_conf.h

@@ -3,14 +3,20 @@
 #define _GPIOA
 #define _GPIOB
 #define _GPIOC
+#define _GPIOD
+#define _GPIOE
 #define _BKP
 #define _AFIO
 #define _USART1
 #define _NVIC
 #define _SysTick
 #define _USB
+#define _TIM1
 #define _TIM2
 #define _TIM3
+#define _TIM4
+#define _I2C1
+#define _I2C2
 #define _DMA1_Channel1
 #define _DMA1_Channel2
 #define _DMA1_Channel3

cpu/arm/stm32f103/usb-arch.c

@@ -522,7 +522,7 @@ read_hw_buffer(USBBuffer *buffer, unsigned int offset, unsigned int len)
 #define USB_WRITE_BLOCK 0x01
 #define USB_WRITE_NOTIFY 0x02
 
-static void
+void
 write_hw_buffer(USBBuffer *buffer,unsigned int offset, unsigned int len)
 {
 #ifdef USB_STM32F103_ENABLE_ALT_COPY
@@ -531,8 +531,11 @@ write_hw_buffer(USBBuffer *buffer,unsigned int offset, unsigned int len)
   } else
 #endif    
     {
-      const uint8_t *data = buffer->data;
+      const uint8_t *data;
-      uint32_t *hw_data = ((u32*)USB_MEM_BASE) + offset/2;
+      uint32_t *hw_data;
+      if (len == 0) return;
+      data = buffer->data;
+      hw_data = ((u32*)USB_MEM_BASE) + offset/2;
       buffer->data += len;
       if (offset & 1) {
 	*hw_data = (*hw_data & 0xff) | (*data++ << 8);
@@ -554,7 +557,7 @@ static unsigned int
 get_receive_capacity(USBBuffer *buffer)
 {
   unsigned int capacity = 0;
-  while(buffer && !(buffer->flags & (USB_BUFFER_IN| USB_BUFFER_SETUP))) {
+  while(buffer && !(buffer->flags & (USB_BUFFER_IN| USB_BUFFER_SETUP|USB_BUFFER_HALT))) {
     capacity += buffer->left;
     buffer = buffer->next;
   }
@@ -761,10 +764,10 @@ start_transmit(USBEndpoint *ep)
     break;
   case USB_EP_FLAGS_TYPE_BULK:
     if (buffer->flags & USB_BUFFER_HALT) {
-      if (ep->status & 0x01) return USB_READ_BLOCK;
+      if (ep->status & 0x01) return USB_WRITE_BLOCK;
       ep->status |= 0x01;
       stall_bulk_in(hw_ep);
-      return USB_READ_BLOCK;
+      return USB_WRITE_BLOCK;
     }
     if (USB->EPR[hw_ep] & USB_EPxR_SW_BUF_TX) {
       hw_offset =  buf_desc->ADDR_TX_1;
@@ -790,10 +793,8 @@ start_transmit(USBEndpoint *ep)
     if (buffer->left == 0) {
       if (buffer->flags & USB_BUFFER_SHORT_END) {
 	if (len == 0) {
-	  /* Avoid endless loop */
-	  buffer->flags &= ~USB_BUFFER_SHORT_END;
 	  /* Send zero length packet. */
-	  break;
+	  break; /* Leave without moving to next buffer */
 	} else {
 	  len = 0;
 	}