[src/trunk]: src/sys/external/bsd/drm2/dist/drm/radeon Use bus_space_read rat...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/e8307b87c4a1
branches:  trunk
changeset: 809208:e8307b87c4a1
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Wed Jun 24 18:23:23 2015 +0000

description:
Use bus_space_read rather than kmemdup to read ROM.

jakllsch@ reports that on some 64-bit systems, kmemdup does 8-byte
reads, which yield garbage in the high word.  bus_space_read_region_1
does 1-byte reads instead, which seem to work.

Derived from a patch from jakllsch@.

diffstat:

 sys/external/bsd/drm2/dist/drm/radeon/radeon_bios.c |  26 +++++++++++++++++++++
 1 files changed, 26 insertions(+), 0 deletions(-)

diffs (43 lines):

diff -r 2e737b89d6a6 -r e8307b87c4a1 sys/external/bsd/drm2/dist/drm/radeon/radeon_bios.c
--- a/sys/external/bsd/drm2/dist/drm/radeon/radeon_bios.c       Wed Jun 24 18:20:36 2015 +0000
+++ b/sys/external/bsd/drm2/dist/drm/radeon/radeon_bios.c       Wed Jun 24 18:23:23 2015 +0000
@@ -116,6 +116,31 @@
                return false;
        }
 
+#ifdef __NetBSD__
+       /*
+        * Using kmemdup results in >4-byte memory access on 64-bit
+        * systems, which yields bogus answers on some devices.  So we
+        * use bus_space(9) to do guaranteed byte access with
+        * bus_space_read_region_1 which seems to work better.
+        */
+    {
+       const bus_space_tag_t bst = rdev->pdev->pd_rom_bst;
+       const bus_space_handle_t bsh = rdev->pdev->pd_rom_found_bsh;
+
+       if (size == 0 ||
+           bus_space_read_1(bst, bsh, 0) != 0x55 ||
+           bus_space_read_1(bst, bsh, 1) != 0xaa) {
+               pci_unmap_rom(rdev->pdev, bios);
+               return false;
+       }
+       rdev->bios = kmalloc(size, GFP_KERNEL);
+       if (rdev->bios == NULL) {
+               pci_unmap_rom(rdev->pdev, bios);
+               return false;
+       }
+       bus_space_read_region_1(bst, bsh, 0, rdev->bios, size);
+    }
+#else
        if (size == 0 || bios[0] != 0x55 || bios[1] != 0xaa) {
                pci_unmap_rom(rdev->pdev, bios);
                return false;
@@ -125,6 +150,7 @@
                pci_unmap_rom(rdev->pdev, bios);
                return false;
        }
+#endif
        pci_unmap_rom(rdev->pdev, bios);
        return true;
 }