ih->use_bus_addr = use_bus_addr;
 
        if (use_bus_addr) {
+               dma_addr_t dma_addr;
+
                if (ih->ring)
                        return 0;
 
                 * add them to the end of the ring allocation.
                 */
                ih->ring = dma_alloc_coherent(adev->dev, ih->ring_size + 8,
-                                             &ih->rb_dma_addr, GFP_KERNEL);
+                                             &dma_addr, GFP_KERNEL);
                if (ih->ring == NULL)
                        return -ENOMEM;
 
                memset((void *)ih->ring, 0, ih->ring_size + 8);
-               ih->wptr_offs = (ih->ring_size / 4) + 0;
-               ih->rptr_offs = (ih->ring_size / 4) + 1;
+               ih->gpu_addr = dma_addr;
+               ih->wptr_addr = dma_addr + ih->ring_size;
+               ih->wptr_cpu = &ih->ring[ih->ring_size / 4];
+               ih->rptr_addr = dma_addr + ih->ring_size + 4;
+               ih->rptr_cpu = &ih->ring[(ih->ring_size / 4) + 1];
        } else {
-               r = amdgpu_device_wb_get(adev, &ih->wptr_offs);
+               unsigned wptr_offs, rptr_offs;
+
+               r = amdgpu_device_wb_get(adev, &wptr_offs);
                if (r)
                        return r;
 
-               r = amdgpu_device_wb_get(adev, &ih->rptr_offs);
+               r = amdgpu_device_wb_get(adev, &rptr_offs);
                if (r) {
-                       amdgpu_device_wb_free(adev, ih->wptr_offs);
+                       amdgpu_device_wb_free(adev, wptr_offs);
                        return r;
                }
 
                                            &ih->ring_obj, &ih->gpu_addr,
                                            (void **)&ih->ring);
                if (r) {
-                       amdgpu_device_wb_free(adev, ih->rptr_offs);
-                       amdgpu_device_wb_free(adev, ih->wptr_offs);
+                       amdgpu_device_wb_free(adev, rptr_offs);
+                       amdgpu_device_wb_free(adev, wptr_offs);
                        return r;
                }
+
+               ih->wptr_addr = adev->wb.gpu_addr + wptr_offs * 4;
+               ih->wptr_cpu = &adev->wb.wb[wptr_offs];
+               ih->rptr_addr = adev->wb.gpu_addr + rptr_offs * 4;
+               ih->rptr_cpu = &adev->wb.wb[rptr_offs];
        }
        return 0;
 }
                 * add them to the end of the ring allocation.
                 */
                dma_free_coherent(adev->dev, ih->ring_size + 8,
-                                 (void *)ih->ring, ih->rb_dma_addr);
+                                 (void *)ih->ring, ih->gpu_addr);
                ih->ring = NULL;
        } else {
                amdgpu_bo_free_kernel(&ih->ring_obj, &ih->gpu_addr,
                                      (void **)&ih->ring);
-               amdgpu_device_wb_free(adev, ih->wptr_offs);
-               amdgpu_device_wb_free(adev, ih->rptr_offs);
+               amdgpu_device_wb_free(adev, (ih->wptr_addr - ih->gpu_addr) / 4);
+               amdgpu_device_wb_free(adev, (ih->rptr_addr - ih->gpu_addr) / 4);
        }
 }
 
 
  * R6xx+ IH ring
  */
 struct amdgpu_ih_ring {
-       struct amdgpu_bo        *ring_obj;
-       volatile uint32_t       *ring;
-       unsigned                rptr;
        unsigned                ring_size;
-       uint64_t                gpu_addr;
        uint32_t                ptr_mask;
-       atomic_t                lock;
-       bool                    enabled;
-       unsigned                wptr_offs;
-       unsigned                rptr_offs;
        u32                     doorbell_index;
        bool                    use_doorbell;
        bool                    use_bus_addr;
-       dma_addr_t              rb_dma_addr; /* only used when use_bus_addr = true */
+
+       struct amdgpu_bo        *ring_obj;
+       volatile uint32_t       *ring;
+       uint64_t                gpu_addr;
+
+       uint64_t                wptr_addr;
+       volatile uint32_t       *wptr_cpu;
+
+       uint64_t                rptr_addr;
+       volatile uint32_t       *rptr_cpu;
+
+       bool                    enabled;
+       unsigned                rptr;
+       atomic_t                lock;
 };
 
 /* provided by the ih block */
 
  */
 static int cik_ih_irq_init(struct amdgpu_device *adev)
 {
+       struct amdgpu_ih_ring *ih = &adev->irq.ih;
        int rb_bufsz;
        u32 interrupt_cntl, ih_cntl, ih_rb_cntl;
-       u64 wptr_off;
 
        /* disable irqs */
        cik_ih_disable_interrupts(adev);
        ih_rb_cntl |= IH_RB_CNTL__WPTR_WRITEBACK_ENABLE_MASK;
 
        /* set the writeback address whether it's enabled or not */
-       wptr_off = adev->wb.gpu_addr + (adev->irq.ih.wptr_offs * 4);
-       WREG32(mmIH_RB_WPTR_ADDR_LO, lower_32_bits(wptr_off));
-       WREG32(mmIH_RB_WPTR_ADDR_HI, upper_32_bits(wptr_off) & 0xFF);
+       WREG32(mmIH_RB_WPTR_ADDR_LO, lower_32_bits(ih->wptr_addr));
+       WREG32(mmIH_RB_WPTR_ADDR_HI, upper_32_bits(ih->wptr_addr) & 0xFF);
 
        WREG32(mmIH_RB_CNTL, ih_rb_cntl);
 
 {
        u32 wptr, tmp;
 
-       wptr = le32_to_cpu(adev->wb.wb[ih->wptr_offs]);
+       wptr = le32_to_cpu(*ih->wptr_cpu);
 
        if (wptr & IH_RB_WPTR__RB_OVERFLOW_MASK) {
                wptr &= ~IH_RB_WPTR__RB_OVERFLOW_MASK;
 
  */
 static int cz_ih_irq_init(struct amdgpu_device *adev)
 {
-       int rb_bufsz;
+       struct amdgpu_ih_ring *ih = &adev->irq.ih;
        u32 interrupt_cntl, ih_cntl, ih_rb_cntl;
-       u64 wptr_off;
+       int rb_bufsz;
 
        /* disable irqs */
        cz_ih_disable_interrupts(adev);
        ih_rb_cntl = REG_SET_FIELD(ih_rb_cntl, IH_RB_CNTL, WPTR_WRITEBACK_ENABLE, 1);
 
        /* set the writeback address whether it's enabled or not */
-       wptr_off = adev->wb.gpu_addr + (adev->irq.ih.wptr_offs * 4);
-       WREG32(mmIH_RB_WPTR_ADDR_LO, lower_32_bits(wptr_off));
-       WREG32(mmIH_RB_WPTR_ADDR_HI, upper_32_bits(wptr_off) & 0xFF);
+       WREG32(mmIH_RB_WPTR_ADDR_LO, lower_32_bits(ih->wptr_addr));
+       WREG32(mmIH_RB_WPTR_ADDR_HI, upper_32_bits(ih->wptr_addr) & 0xFF);
 
        WREG32(mmIH_RB_CNTL, ih_rb_cntl);
 
 {
        u32 wptr, tmp;
 
-       wptr = le32_to_cpu(adev->wb.wb[ih->wptr_offs]);
+       wptr = le32_to_cpu(*ih->wptr_cpu);
 
        if (REG_GET_FIELD(wptr, IH_RB_WPTR, RB_OVERFLOW)) {
                wptr = REG_SET_FIELD(wptr, IH_RB_WPTR, RB_OVERFLOW, 0);
 
  */
 static int iceland_ih_irq_init(struct amdgpu_device *adev)
 {
+       struct amdgpu_ih_ring *ih = &adev->irq.ih;
        int rb_bufsz;
        u32 interrupt_cntl, ih_cntl, ih_rb_cntl;
-       u64 wptr_off;
 
        /* disable irqs */
        iceland_ih_disable_interrupts(adev);
        ih_rb_cntl = REG_SET_FIELD(ih_rb_cntl, IH_RB_CNTL, WPTR_WRITEBACK_ENABLE, 1);
 
        /* set the writeback address whether it's enabled or not */
-       wptr_off = adev->wb.gpu_addr + (adev->irq.ih.wptr_offs * 4);
-       WREG32(mmIH_RB_WPTR_ADDR_LO, lower_32_bits(wptr_off));
-       WREG32(mmIH_RB_WPTR_ADDR_HI, upper_32_bits(wptr_off) & 0xFF);
+       WREG32(mmIH_RB_WPTR_ADDR_LO, lower_32_bits(ih->wptr_addr));
+       WREG32(mmIH_RB_WPTR_ADDR_HI, upper_32_bits(ih->wptr_addr) & 0xFF);
 
        WREG32(mmIH_RB_CNTL, ih_rb_cntl);
 
 {
        u32 wptr, tmp;
 
-       wptr = le32_to_cpu(adev->wb.wb[ih->wptr_offs]);
+       wptr = le32_to_cpu(*ih->wptr_cpu);
 
        if (REG_GET_FIELD(wptr, IH_RB_WPTR, RB_OVERFLOW)) {
                wptr = REG_SET_FIELD(wptr, IH_RB_WPTR, RB_OVERFLOW, 0);
 
 
 static int si_ih_irq_init(struct amdgpu_device *adev)
 {
+       struct amdgpu_ih_ring *ih = &adev->irq.ih;
        int rb_bufsz;
        u32 interrupt_cntl, ih_cntl, ih_rb_cntl;
-       u64 wptr_off;
 
        si_ih_disable_interrupts(adev);
        WREG32(INTERRUPT_CNTL2, adev->irq.ih.gpu_addr >> 8);
                     (rb_bufsz << 1) |
                     IH_WPTR_WRITEBACK_ENABLE;
 
-       wptr_off = adev->wb.gpu_addr + (adev->irq.ih.wptr_offs * 4);
-       WREG32(IH_RB_WPTR_ADDR_LO, lower_32_bits(wptr_off));
-       WREG32(IH_RB_WPTR_ADDR_HI, upper_32_bits(wptr_off) & 0xFF);
+       WREG32(IH_RB_WPTR_ADDR_LO, lower_32_bits(ih->wptr_addr));
+       WREG32(IH_RB_WPTR_ADDR_HI, upper_32_bits(ih->wptr_addr) & 0xFF);
        WREG32(IH_RB_CNTL, ih_rb_cntl);
        WREG32(IH_RB_RPTR, 0);
        WREG32(IH_RB_WPTR, 0);
 {
        u32 wptr, tmp;
 
-       wptr = le32_to_cpu(adev->wb.wb[ih->wptr_offs]);
+       wptr = le32_to_cpu(*ih->wptr_cpu);
 
        if (wptr & IH_RB_WPTR__RB_OVERFLOW_MASK) {
                wptr &= ~IH_RB_WPTR__RB_OVERFLOW_MASK;
 
  */
 static int tonga_ih_irq_init(struct amdgpu_device *adev)
 {
-       int rb_bufsz;
        u32 interrupt_cntl, ih_rb_cntl, ih_doorbell_rtpr;
-       u64 wptr_off;
+       struct amdgpu_ih_ring *ih = &adev->irq.ih;
+       int rb_bufsz;
 
        /* disable irqs */
        tonga_ih_disable_interrupts(adev);
        WREG32(mmINTERRUPT_CNTL, interrupt_cntl);
 
        /* Ring Buffer base. [39:8] of 40-bit address of the beginning of the ring buffer*/
-       if (adev->irq.ih.use_bus_addr)
-               WREG32(mmIH_RB_BASE, adev->irq.ih.rb_dma_addr >> 8);
-       else
-               WREG32(mmIH_RB_BASE, adev->irq.ih.gpu_addr >> 8);
+       WREG32(mmIH_RB_BASE, ih->gpu_addr >> 8);
 
        rb_bufsz = order_base_2(adev->irq.ih.ring_size / 4);
        ih_rb_cntl = REG_SET_FIELD(0, IH_RB_CNTL, WPTR_OVERFLOW_CLEAR, 1);
        WREG32(mmIH_RB_CNTL, ih_rb_cntl);
 
        /* set the writeback address whether it's enabled or not */
-       if (adev->irq.ih.use_bus_addr)
-               wptr_off = adev->irq.ih.rb_dma_addr + (adev->irq.ih.wptr_offs * 4);
-       else
-               wptr_off = adev->wb.gpu_addr + (adev->irq.ih.wptr_offs * 4);
-       WREG32(mmIH_RB_WPTR_ADDR_LO, lower_32_bits(wptr_off));
-       WREG32(mmIH_RB_WPTR_ADDR_HI, upper_32_bits(wptr_off) & 0xFF);
+       WREG32(mmIH_RB_WPTR_ADDR_LO, lower_32_bits(ih->wptr_addr));
+       WREG32(mmIH_RB_WPTR_ADDR_HI, upper_32_bits(ih->wptr_addr) & 0xFF);
 
        /* set rptr, wptr to 0 */
        WREG32(mmIH_RB_RPTR, 0);
 {
        u32 wptr, tmp;
 
-       if (adev->irq.ih.use_bus_addr)
-               wptr = le32_to_cpu(ih->ring[ih->wptr_offs]);
-       else
-               wptr = le32_to_cpu(adev->wb.wb[ih->wptr_offs]);
+       wptr = le32_to_cpu(*ih->wptr_cpu);
 
        if (REG_GET_FIELD(wptr, IH_RB_WPTR, RB_OVERFLOW)) {
                wptr = REG_SET_FIELD(wptr, IH_RB_WPTR, RB_OVERFLOW, 0);
 {
        if (ih->use_doorbell) {
                /* XXX check if swapping is necessary on BE */
-               if (ih->use_bus_addr)
-                       ih->ring[ih->rptr_offs] = ih->rptr;
-               else
-                       adev->wb.wb[ih->rptr_offs] = ih->rptr;
+               *ih->rptr_cpu = ih->rptr;
                WDOORBELL32(ih->doorbell_index, ih->rptr);
        } else {
                WREG32(mmIH_RB_RPTR, ih->rptr);
 
  */
 static int vega10_ih_irq_init(struct amdgpu_device *adev)
 {
+       struct amdgpu_ih_ring *ih = &adev->irq.ih;
        int ret = 0;
        int rb_bufsz;
        u32 ih_rb_cntl, ih_doorbell_rtpr;
        u32 tmp;
-       u64 wptr_off;
 
        /* disable irqs */
        vega10_ih_disable_interrupts(adev);
 
        ih_rb_cntl = RREG32_SOC15(OSSSYS, 0, mmIH_RB_CNTL);
        /* Ring Buffer base. [39:8] of 40-bit address of the beginning of the ring buffer*/
-       if (adev->irq.ih.use_bus_addr) {
-               WREG32_SOC15(OSSSYS, 0, mmIH_RB_BASE, adev->irq.ih.rb_dma_addr >> 8);
-               WREG32_SOC15(OSSSYS, 0, mmIH_RB_BASE_HI, ((u64)adev->irq.ih.rb_dma_addr >> 40) & 0xff);
-               ih_rb_cntl = REG_SET_FIELD(ih_rb_cntl, IH_RB_CNTL, MC_SPACE, 1);
-       } else {
-               WREG32_SOC15(OSSSYS, 0, mmIH_RB_BASE, adev->irq.ih.gpu_addr >> 8);
-               WREG32_SOC15(OSSSYS, 0, mmIH_RB_BASE_HI, (adev->irq.ih.gpu_addr >> 40) & 0xff);
-               ih_rb_cntl = REG_SET_FIELD(ih_rb_cntl, IH_RB_CNTL, MC_SPACE, 4);
-       }
+       WREG32_SOC15(OSSSYS, 0, mmIH_RB_BASE, adev->irq.ih.gpu_addr >> 8);
+       WREG32_SOC15(OSSSYS, 0, mmIH_RB_BASE_HI,
+                    (adev->irq.ih.gpu_addr >> 40) & 0xff);
+       ih_rb_cntl = REG_SET_FIELD(ih_rb_cntl, IH_RB_CNTL, MC_SPACE,
+                                  ih->use_bus_addr ? 1 : 4);
        rb_bufsz = order_base_2(adev->irq.ih.ring_size / 4);
        ih_rb_cntl = REG_SET_FIELD(ih_rb_cntl, IH_RB_CNTL, WPTR_OVERFLOW_CLEAR, 1);
        ih_rb_cntl = REG_SET_FIELD(ih_rb_cntl, IH_RB_CNTL, WPTR_OVERFLOW_ENABLE, 1);
        WREG32_SOC15(OSSSYS, 0, mmIH_RB_CNTL, ih_rb_cntl);
 
        /* set the writeback address whether it's enabled or not */
-       if (adev->irq.ih.use_bus_addr)
-               wptr_off = adev->irq.ih.rb_dma_addr + (adev->irq.ih.wptr_offs * 4);
-       else
-               wptr_off = adev->wb.gpu_addr + (adev->irq.ih.wptr_offs * 4);
-       WREG32_SOC15(OSSSYS, 0, mmIH_RB_WPTR_ADDR_LO, lower_32_bits(wptr_off));
-       WREG32_SOC15(OSSSYS, 0, mmIH_RB_WPTR_ADDR_HI, upper_32_bits(wptr_off) & 0xFFFF);
+       WREG32_SOC15(OSSSYS, 0, mmIH_RB_WPTR_ADDR_LO,
+                    lower_32_bits(ih->wptr_addr));
+       WREG32_SOC15(OSSSYS, 0, mmIH_RB_WPTR_ADDR_HI,
+                    upper_32_bits(ih->wptr_addr) & 0xFFFF);
 
        /* set rptr, wptr to 0 */
        WREG32_SOC15(OSSSYS, 0, mmIH_RB_RPTR, 0);
 {
        u32 wptr, tmp;
 
-       if (ih->use_bus_addr)
-               wptr = le32_to_cpu(ih->ring[ih->wptr_offs]);
-       else
-               wptr = le32_to_cpu(adev->wb.wb[ih->wptr_offs]);
+       wptr = le32_to_cpu(*ih->wptr_cpu);
 
        if (REG_GET_FIELD(wptr, IH_RB_WPTR, RB_OVERFLOW)) {
                wptr = REG_SET_FIELD(wptr, IH_RB_WPTR, RB_OVERFLOW, 0);
 {
        if (ih->use_doorbell) {
                /* XXX check if swapping is necessary on BE */
-               if (ih->use_bus_addr)
-                       ih->ring[ih->rptr_offs] = ih->rptr;
-               else
-                       adev->wb.wb[ih->rptr_offs] = ih->rptr;
+               *ih->rptr_cpu = ih->rptr;
                WDOORBELL32(ih->doorbell_index, ih->rptr);
        } else {
                WREG32_SOC15(OSSSYS, 0, mmIH_RB_RPTR, ih->rptr);