IB/mlx5: Mmap the HCA's core clock register to user-space

In order to read the HCA's current cycles register, we need
to map it to user-space. Add support to map this register
via mmap command.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Reviewed-by: Moshe Lazer <moshel@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index a3ae9cc..602f067 100644 (file)
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -1023,6 +1023,34 @@ static int mlx5_ib_mmap(struct ib_ucontext *ibcontext, struct vm_area_struct *vm
        case MLX5_IB_MMAP_GET_CONTIGUOUS_PAGES:
                return -ENOSYS;
 
+       case MLX5_IB_MMAP_CORE_CLOCK:
+       {
+               phys_addr_t pfn;
+
+               if (vma->vm_end - vma->vm_start != PAGE_SIZE)
+                       return -EINVAL;
+
+               if (vma->vm_flags & (VM_WRITE | VM_EXEC))
+                       return -EPERM;
+
+               /* Don't expose to user-space information it shouldn't have */
+               if (PAGE_SIZE > 4096)
+                       return -EOPNOTSUPP;
+
+               vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+               pfn = (dev->mdev->iseg_base +
+                      offsetof(struct mlx5_init_seg, internal_timer_h)) >>
+                       PAGE_SHIFT;
+               if (io_remap_pfn_range(vma, vma->vm_start, pfn,
+                                      PAGE_SIZE, vma->vm_page_prot))
+                       return -EAGAIN;
+
+               mlx5_ib_dbg(dev, "mapped internal timer at 0x%lx, PA 0x%llx\n",
+                           vma->vm_start,
+                           (unsigned long long)pfn << PAGE_SHIFT);
+               break;
+       }
+
        default:
                return -EINVAL;
        }

diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index b2a6643..1303487 100644 (file)
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -65,7 +65,9 @@ enum {
 
 enum mlx5_ib_mmap_cmd {
        MLX5_IB_MMAP_REGULAR_PAGE               = 0,
-       MLX5_IB_MMAP_GET_CONTIGUOUS_PAGES       = 1, /* always last */
+       MLX5_IB_MMAP_GET_CONTIGUOUS_PAGES       = 1,
+       /* 5 is chosen in order to be compatible with old versions of libmlx5 */
+       MLX5_IB_MMAP_CORE_CLOCK                 = 5,
 };
 
 enum {