Index: uspace/drv/bus/usb/ohci/hc.c
===================================================================
--- uspace/drv/bus/usb/ohci/hc.c	(revision 4e303698747a0ba8aeec57c13ddd27877639ac60)
+++ uspace/drv/bus/usb/ohci/hc.c	(revision 65eac7b67b0bf71d40b3356ec132184b3e8dc80c)
@@ -515,7 +515,7 @@
 
 	/* Enable queues */
-//	OHCI_SET(instance->registers->control, (C_PLE | C_IE | C_CLE | C_BLE));
-//	usb_log_debug("Queues enabled(%x).\n",
-//	    OHCI_RD(instance->registers->control));
+	OHCI_SET(instance->registers->control, (C_PLE | C_IE | C_CLE | C_BLE));
+	usb_log_debug("Queues enabled(%x).\n",
+	    OHCI_RD(instance->registers->control));
 
 	/* Enable interrupts */
@@ -596,6 +596,6 @@
 
 	for (unsigned i = 0; i < 32; ++i) {
-		instance->hcca->int_ep[i] =
-		    instance->lists[USB_TRANSFER_INTERRUPT].list_head_pa;
+		OHCI_WR(instance->hcca->int_ep[i],
+		    instance->lists[USB_TRANSFER_INTERRUPT].list_head_pa);
 	}
 	usb_log_debug2("Interrupt HEADs set to: %p (%#" PRIx32 ").\n",
Index: uspace/drv/bus/usb/ohci/hw_struct/endpoint_descriptor.c
===================================================================
--- uspace/drv/bus/usb/ohci/hw_struct/endpoint_descriptor.c	(revision 4e303698747a0ba8aeec57c13ddd27877639ac60)
+++ uspace/drv/bus/usb/ohci/hw_struct/endpoint_descriptor.c	(revision 65eac7b67b0bf71d40b3356ec132184b3e8dc80c)
@@ -58,5 +58,5 @@
 		/* Mark as dead, used for dummy EDs at the beginning of
 		 * endpoint lists. */
-		instance->status = ED_STATUS_K_FLAG;
+		OHCI_WR(instance->status, ED_STATUS_K_FLAG);
 		return;
 	}
@@ -65,27 +65,27 @@
 
 	/* Status: address, endpoint nr, direction mask and max packet size. */
-	instance->status = 0
-	    | ((ep->address & ED_STATUS_FA_MASK) << ED_STATUS_FA_SHIFT)
+	OHCI_WR(instance->status,
+	    ((ep->address & ED_STATUS_FA_MASK) << ED_STATUS_FA_SHIFT)
 	    | ((ep->endpoint & ED_STATUS_EN_MASK) << ED_STATUS_EN_SHIFT)
 	    | ((dir[ep->direction] & ED_STATUS_D_MASK) << ED_STATUS_D_SHIFT)
 	    | ((ep->max_packet_size & ED_STATUS_MPS_MASK)
-	        << ED_STATUS_MPS_SHIFT);
+	        << ED_STATUS_MPS_SHIFT));
 
 	/* Low speed flag */
 	if (ep->speed == USB_SPEED_LOW)
-		instance->status |= ED_STATUS_S_FLAG;
+		OHCI_SET(instance->status, ED_STATUS_S_FLAG);
 
 	/* Isochronous format flag */
 	if (ep->transfer_type == USB_TRANSFER_ISOCHRONOUS)
-		instance->status |= ED_STATUS_F_FLAG;
+		OHCI_SET(instance->status, ED_STATUS_F_FLAG);
 
 	/* Set TD to the list */
 	const uintptr_t pa = addr_to_phys(td);
-	instance->td_head = pa & ED_TDHEAD_PTR_MASK;
-	instance->td_tail = pa & ED_TDTAIL_PTR_MASK;
+	OHCI_WR(instance->td_head, pa & ED_TDHEAD_PTR_MASK);
+	OHCI_WR(instance->td_tail, pa & ED_TDTAIL_PTR_MASK);
 
 	/* Set toggle bit */
 	if (ep->toggle)
-		instance->td_head |= ED_TDHEAD_TOGGLE_CARRY;
+		OHCI_SET(instance->td_head, ED_TDHEAD_TOGGLE_CARRY);
 
 }
Index: uspace/drv/bus/usb/ohci/hw_struct/endpoint_descriptor.h
===================================================================
--- uspace/drv/bus/usb/ohci/hw_struct/endpoint_descriptor.h	(revision 4e303698747a0ba8aeec57c13ddd27877639ac60)
+++ uspace/drv/bus/usb/ohci/hw_struct/endpoint_descriptor.h	(revision 65eac7b67b0bf71d40b3356ec132184b3e8dc80c)
@@ -40,4 +40,5 @@
 #include <usb/host/endpoint.h>
 
+#include "../ohci_regs.h"
 #include "../utils/malloc32.h"
 #include "transfer_descriptor.h"
@@ -116,6 +117,12 @@
 {
 	assert(instance);
-	return (instance->td_head & ED_TDHEAD_HALTED_FLAG)
-	    || (instance->status & ED_STATUS_K_FLAG);
+	return (OHCI_RD(instance->td_head) & ED_TDHEAD_HALTED_FLAG)
+	    || (OHCI_RD(instance->status) & ED_STATUS_K_FLAG);
+}
+
+static inline void ed_clear_halt(ed_t *instance)
+{
+	assert(instance);
+	OHCI_CLR(instance->td_head, ED_TDHEAD_HALTED_FLAG);
 }
 
@@ -128,6 +135,6 @@
 {
 	assert(instance);
-	return (instance->td_head & ED_TDHEAD_PTR_MASK)
-	    != (instance->td_tail & ED_TDTAIL_PTR_MASK);
+	return (OHCI_RD(instance->td_head) & ED_TDHEAD_PTR_MASK)
+	    != (OHCI_RD(instance->td_tail) & ED_TDTAIL_PTR_MASK);
 }
 
@@ -141,5 +148,17 @@
 	assert(instance);
 	const uintptr_t pa = addr_to_phys(td);
-	instance->td_tail = pa & ED_TDTAIL_PTR_MASK;
+	OHCI_WR(instance->td_tail, pa & ED_TDTAIL_PTR_MASK);
+}
+
+static inline uint32_t ed_tail_td(const ed_t *instance)
+{
+	assert(instance);
+	return OHCI_RD(instance->td_tail) & ED_TDTAIL_PTR_MASK;
+}
+
+static inline uint32_t ed_head_td(const ed_t *instance)
+{
+	assert(instance);
+	return OHCI_RD(instance->td_head) & ED_TDHEAD_PTR_MASK;
 }
 
@@ -155,5 +174,5 @@
 	const uint32_t pa = addr_to_phys(next);
 	assert((pa & ED_NEXT_PTR_MASK) << ED_NEXT_PTR_SHIFT == pa);
-	instance->next = pa;
+	OHCI_WR(instance->next, pa);
 }
 
@@ -166,5 +185,5 @@
 {
 	assert(instance);
-	return (instance->td_head & ED_TDHEAD_TOGGLE_CARRY) ? 1 : 0;
+	return (OHCI_RD(instance->td_head) & ED_TDHEAD_TOGGLE_CARRY) ? 1 : 0;
 }
 
@@ -178,9 +197,9 @@
 	assert(instance);
 	if (toggle) {
-		instance->td_head |= ED_TDHEAD_TOGGLE_CARRY;
+		OHCI_SET(instance->td_head, ED_TDHEAD_TOGGLE_CARRY);
 	} else {
 		/* Clear halted flag when reseting toggle TODO: Why? */
-		instance->td_head &= ~ED_TDHEAD_TOGGLE_CARRY;
-		instance->td_head &= ~ED_TDHEAD_HALTED_FLAG;
+		OHCI_CLR(instance->td_head, ED_TDHEAD_TOGGLE_CARRY);
+		OHCI_CLR(instance->td_head, ED_TDHEAD_HALTED_FLAG);
 	}
 }
Index: uspace/drv/bus/usb/ohci/hw_struct/transfer_descriptor.c
===================================================================
--- uspace/drv/bus/usb/ohci/hw_struct/transfer_descriptor.c	(revision 4e303698747a0ba8aeec57c13ddd27877639ac60)
+++ uspace/drv/bus/usb/ohci/hw_struct/transfer_descriptor.c	(revision 65eac7b67b0bf71d40b3356ec132184b3e8dc80c)
@@ -33,4 +33,6 @@
  */
 #include <usb/usb.h>
+#include <mem.h>
+#include "../utils/malloc32.h"
 #include "transfer_descriptor.h"
 
@@ -58,26 +60,26 @@
 	bzero(instance, sizeof(td_t));
 	/* Set PID and Error code */
-	instance->status = 0
-	    | ((dir[direction] & TD_STATUS_DP_MASK) << TD_STATUS_DP_SHIFT)
-	    | ((CC_NOACCESS2 & TD_STATUS_CC_MASK) << TD_STATUS_CC_SHIFT);
+	OHCI_WR(instance->status,
+	    ((dir[direction] & TD_STATUS_DP_MASK) << TD_STATUS_DP_SHIFT)
+	    | ((CC_NOACCESS2 & TD_STATUS_CC_MASK) << TD_STATUS_CC_SHIFT));
 
 	if (toggle == 0 || toggle == 1) {
 		/* Set explicit toggle bit */
-		instance->status |= TD_STATUS_T_USE_TD_FLAG;
-		instance->status |= toggle ? TD_STATUS_T_FLAG : 0;
+		OHCI_SET(instance->status, TD_STATUS_T_USE_TD_FLAG);
+		OHCI_SET(instance->status, toggle ? TD_STATUS_T_FLAG : 0);
 	}
 
 	/* Alow less data on input. */
 	if (dir == USB_DIRECTION_IN) {
-		instance->status |= TD_STATUS_ROUND_FLAG;
+		OHCI_SET(instance->status, TD_STATUS_ROUND_FLAG);
 	}
 
 	if (buffer != NULL) {
 		assert(size != 0);
-		instance->cbp = addr_to_phys(buffer);
-		instance->be = addr_to_phys(buffer + size - 1);
+		OHCI_WR(instance->cbp, addr_to_phys(buffer));
+		OHCI_WR(instance->be, addr_to_phys(buffer + size - 1));
 	}
 
-	instance->next = addr_to_phys(next) & TD_NEXT_PTR_MASK;
+	OHCI_WR(instance->next, addr_to_phys(next) & TD_NEXT_PTR_MASK);
 
 }
Index: uspace/drv/bus/usb/ohci/hw_struct/transfer_descriptor.h
===================================================================
--- uspace/drv/bus/usb/ohci/hw_struct/transfer_descriptor.h	(revision 4e303698747a0ba8aeec57c13ddd27877639ac60)
+++ uspace/drv/bus/usb/ohci/hw_struct/transfer_descriptor.h	(revision 65eac7b67b0bf71d40b3356ec132184b3e8dc80c)
@@ -38,5 +38,5 @@
 #include <stdint.h>
 
-#include "../utils/malloc32.h"
+#include "../ohci_regs.h"
 #include "completion_codes.h"
 
@@ -100,6 +100,6 @@
 {
 	assert(instance);
-	const int cc =
-	    (instance->status >> TD_STATUS_CC_SHIFT) & TD_STATUS_CC_MASK;
+	const int cc =(OHCI_RD(instance->status)
+	    >> TD_STATUS_CC_SHIFT) & TD_STATUS_CC_MASK;
 	/* This value is changed on transfer completion,
 	 * either to CC_NOERROR or and error code.
@@ -119,6 +119,6 @@
 {
 	assert(instance);
-	const int cc =
-	    (instance->status >> TD_STATUS_CC_SHIFT) & TD_STATUS_CC_MASK;
+	const int cc = (OHCI_RD(instance->status)
+	    >> TD_STATUS_CC_SHIFT) & TD_STATUS_CC_MASK;
 	return cc_to_rc(cc);
 }
@@ -136,5 +136,5 @@
 		return 0;
 	/* Buffer end points to the last byte of transfer buffer, so add 1 */
-	return instance->be - instance->cbp + 1;
+	return OHCI_RD(instance->be) - OHCI_RD(instance->cbp) + 1;
 }
 #endif
Index: uspace/drv/bus/usb/ohci/ohci_batch.c
===================================================================
--- uspace/drv/bus/usb/ohci/ohci_batch.c	(revision 4e303698747a0ba8aeec57c13ddd27877639ac60)
+++ uspace/drv/bus/usb/ohci/ohci_batch.c	(revision 65eac7b67b0bf71d40b3356ec132184b3e8dc80c)
@@ -231,14 +231,13 @@
 
 			/* Check TD assumption */
-			const uint32_t pa =
-			    addr_to_phys(ohci_batch->tds[leave_td]);
-			assert((ohci_batch->ed->td_head & ED_TDHEAD_PTR_MASK)
-			    == pa);
-
+			assert(ed_head_td(ohci_batch->ed) ==
+			    addr_to_phys(ohci_batch->tds[leave_td]));
+
+			/* Set tail to the same TD */
 			ed_set_tail_td(ohci_batch->ed,
 			    ohci_batch->tds[leave_td]);
 
 			/* Clear possible ED HALT */
-			ohci_batch->ed->td_head &= ~ED_TDHEAD_HALTED_FLAG;
+			ed_clear_halt(ohci_batch->ed);
 			break;
 		}
@@ -253,7 +252,9 @@
 
 	/* Make sure that we are leaving the right TD behind */
-	const uint32_t pa = addr_to_phys(ohci_ep->td);
-	assert(pa == (ohci_batch->ed->td_head & ED_TDHEAD_PTR_MASK));
-	assert(pa == (ohci_batch->ed->td_tail & ED_TDTAIL_PTR_MASK));
+	assert(addr_to_phys(ohci_ep->td) == ed_head_td(ohci_batch->ed));
+	assert(addr_to_phys(ohci_ep->td) == ed_tail_td(ohci_batch->ed));
+//	const uint32_t pa = addr_to_phys(ohci_ep->td);
+//	assert(pa == (ohci_batch->ed->td_head & ED_TDHEAD_PTR_MASK));
+//	assert(pa == (ohci_batch->ed->td_tail & ED_TDTAIL_PTR_MASK));
 
 	return true;