Index: uspace/drv/bus/usb/ohci/hc.c
===================================================================
--- uspace/drv/bus/usb/ohci/hc.c	(revision eb212e70f73e6c51b0393c67ea1e45940de721b4)
+++ uspace/drv/bus/usb/ohci/hc.c	(revision 5d360624a93a76b37638a8f8649329c5b272ea81)
@@ -93,4 +93,6 @@
 	ohci_regs_t *registers;
 	const int ret = pio_enable((void*)regs, reg_size, (void**)&registers);
+	if (ret != EOK)
+		return ret;
 
 	/* Some bogus access to force create mapping. DO NOT remove,
@@ -105,7 +107,4 @@
 	 */
 	registers->revision;
-
-	if (ret != EOK)
-		return ret;
 
 	memcpy(cmds, ohci_irq_commands, sizeof(ohci_irq_commands));
Index: uspace/drv/bus/usb/ohci/ohci.c
===================================================================
--- uspace/drv/bus/usb/ohci/ohci.c	(revision eb212e70f73e6c51b0393c67ea1e45940de721b4)
+++ uspace/drv/bus/usb/ohci/ohci.c	(revision 5d360624a93a76b37638a8f8649329c5b272ea81)
@@ -209,6 +209,5 @@
 
 	/* Register handler to avoid interrupt lockup */
-	ret = register_interrupt_handler(device, irq, irq_handler,
-	    &irq_code);
+	ret = register_interrupt_handler(device, irq, irq_handler, &irq_code);
 	CHECK_RET_DEST_FREE_RETURN(ret,
 	    "Failed to register interrupt handler: %s.\n", str_error(ret));
Index: uspace/drv/bus/usb/ohci/ohci_regs.h
===================================================================
--- uspace/drv/bus/usb/ohci/ohci_regs.h	(revision eb212e70f73e6c51b0393c67ea1e45940de721b4)
+++ uspace/drv/bus/usb/ohci/ohci_regs.h	(revision 5d360624a93a76b37638a8f8649329c5b272ea81)
@@ -34,5 +34,5 @@
 #ifndef DRV_OHCI_OHCI_REGS_H
 #define DRV_OHCI_OHCI_REGS_H
-#include <stdint.h>
+#include <sys/types.h>
 
 #define LEGACY_REGS_OFFSET 0x100
@@ -40,10 +40,10 @@
 /** OHCI memory mapped registers structure */
 typedef struct ohci_regs {
-	const volatile uint32_t revision;
+	const ioport32_t revision;
 #define R_REVISION_MASK (0x3f)
 #define R_REVISION_SHIFT (0)
 #define R_LEGACY_FLAG   (0x80)
 
-	volatile uint32_t control;
+	ioport32_t control;
 #define C_CBSR_MASK (0x3) /* Control-bulk service ratio */
 #define C_CBSR_1_1  (0x0)
@@ -78,5 +78,5 @@
 #define C_RWE (1 << 10)  /* Remote wakeup enable */
 
-	volatile uint32_t command_status;
+	ioport32_t command_status;
 #define CS_HCR (1 << 0)   /* Host controller reset */
 #define CS_CLF (1 << 1)   /* Control list filled */
@@ -90,7 +90,7 @@
 	 * writing causes enable/disable,
 	 * status is write-clean (writing 1 clears the bit*/
-	volatile uint32_t interrupt_status;
-	volatile uint32_t interrupt_enable;
-	volatile uint32_t interrupt_disable;
+	ioport32_t interrupt_status;
+	ioport32_t interrupt_enable;
+	ioport32_t interrupt_disable;
 #define I_SO   (1 << 0)   /* Scheduling overrun */
 #define I_WDH  (1 << 1)   /* Done head write-back */
@@ -104,27 +104,27 @@
 
 	/** HCCA pointer (see hw_struct hcca.h) */
-	volatile uint32_t hcca;
+	ioport32_t hcca;
 #define HCCA_PTR_MASK 0xffffff00 /* HCCA is 256B aligned */
 
 	/** Currently executed periodic endpoint */
-	const volatile uint32_t periodic_current;
+	const ioport32_t periodic_current;
 
 	/** The first control endpoint */
-	volatile uint32_t control_head;
+	ioport32_t control_head;
 
 	/** Currently executed control endpoint */
-	volatile uint32_t control_current;
+	ioport32_t control_current;
 
 	/** The first bulk endpoint */
-	volatile uint32_t bulk_head;
+	ioport32_t bulk_head;
 
 	/** Currently executed bulk endpoint */
-	volatile uint32_t bulk_current;
+	ioport32_t bulk_current;
 
 	/** Done TD list, this value is periodically written to HCCA */
-	const volatile uint32_t done_head;
+	const ioport32_t done_head;
 
 	/** Frame time and max packet size for all transfers */
-	volatile uint32_t fm_interval;
+	ioport32_t fm_interval;
 #define FMI_FI_MASK (0x3fff) /* Frame interval in bit times (should be 11999)*/
 #define FMI_FI_SHIFT (0)
@@ -134,5 +134,5 @@
 
 	/** Bit times remaining in current frame */
-	const volatile uint32_t fm_remaining;
+	const ioport32_t fm_remaining;
 #define FMR_FR_MASK FMI_FI_MASK
 #define FMR_FR_SHIFT FMI_FI_SHIFT
@@ -140,17 +140,17 @@
 
 	/** Frame number */
-	const volatile uint32_t fm_number;
+	const ioport32_t fm_number;
 #define FMN_NUMBER_MASK (0xffff)
 
 	/** Remaining bit time in frame to start periodic transfers */
-	volatile uint32_t periodic_start;
+	ioport32_t periodic_start;
 #define PS_PS_MASK (0x3fff) /* bit time when periodic get priority (0x3e67) */
 
 	/** Threshold for starting LS transaction */
-	volatile uint32_t ls_threshold;
+	ioport32_t ls_threshold;
 #define LST_LST_MASK (0x7fff)
 
 	/** The first root hub control register */
-	volatile uint32_t rh_desc_a;
+	ioport32_t rh_desc_a;
 #define RHDA_NDS_MASK (0xff) /* Number of downstream ports, max 15 */
 #define RHDA_NDS_SHIFT (0)
@@ -164,5 +164,5 @@
 
 	/** The other root hub control register */
-	volatile uint32_t rh_desc_b;
+	ioport32_t rh_desc_b;
 #define RHDB_DR_MASK (0xffff) /* Device removable mask */
 #define RHDB_DR_SHIFT (0)
@@ -176,5 +176,5 @@
 
 	/** Root hub status register */
-	volatile uint32_t rh_status;
+	ioport32_t rh_status;
 #define RHS_LPS_FLAG  (1 <<  0)/* read: 0,
                                 * write: 0-no effect,
@@ -198,5 +198,5 @@
 
 	/** Root hub per port status */
-	volatile uint32_t rh_port_status[];
+	ioport32_t rh_port_status[];
 #define RHPS_CCS_FLAG (1 << 0) /* r: current connect status,
                                 * w: 1-clear port enable, 0-nothing */