drm: rework radeon memory map (radeon 1.23)

This code reworks the radeon memory map so it works better
for newer r300 chips and for a lot of older PCI chips.

It really requires a new X driver in order to take advantage of this code.

From: Ben Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Dave Airlie <airlied@linux.ie>

1 files changed, 46 insertions, 12 deletions

diff --git a/drivers/char/drm/radeon_state.c b/drivers/char/drm/radeon_state.c
index 7bc27516d425..56e56b873616 100644
--- a/drivers/char/drm/radeon_state.c
+++ b/drivers/char/drm/radeon_state.c
@@ -45,22 +45,53 @@ static __inline__ int radeon_check_and_fixup_offset(drm_radeon_private_t *
         u32 off = *offset;
         struct drm_radeon_driver_file_fields *radeon_priv;
 
-        if (off >= dev_priv->fb_location &&
-            off < (dev_priv->gart_vm_start + dev_priv->gart_size))
-                return 0;
-
-        radeon_priv = filp_priv->driver_priv;
-        off += radeon_priv->radeon_fb_delta;
+        /* Hrm ... the story of the offset ... So this function converts
+         * the various ideas of what userland clients might have for an
+         * offset in the card address space into an offset into the card
+         * address space :) So with a sane client, it should just keep
+         * the value intact and just do some boundary checking. However,
+         * not all clients are sane. Some older clients pass us 0 based
+         * offsets relative to the start of the framebuffer and some may
+         * assume the AGP aperture it appended to the framebuffer, so we
+         * try to detect those cases and fix them up.
+         *
+         * Note: It might be a good idea here to make sure the offset lands
+         * in some "allowed" area to protect things like the PCIE GART...
+         */
 
-        DRM_DEBUG("offset fixed up to 0x%x\n", off);
+        /* First, the best case, the offset already lands in either the
+         * framebuffer or the GART mapped space
+         */
+        if ((off >= dev_priv->fb_location &&
+             off < (dev_priv->fb_location + dev_priv->fb_size)) ||
+            (off >= dev_priv->gart_vm_start &&
+             off < (dev_priv->gart_vm_start + dev_priv->gart_size)))
+                return 0;
 
-        if (off < dev_priv->fb_location ||
-            off >= (dev_priv->gart_vm_start + dev_priv->gart_size))
-                return DRM_ERR(EINVAL);
+        /* Ok, that didn't happen... now check if we have a zero based
+         * offset that fits in the framebuffer + gart space, apply the
+         * magic offset we get from SETPARAM or calculated from fb_location
+         */
+        if (off < (dev_priv->fb_size + dev_priv->gart_size)) {
+                radeon_priv = filp_priv->driver_priv;
+                off += radeon_priv->radeon_fb_delta;
+        }
 
-        *offset = off;
+        /* Finally, assume we aimed at a GART offset if beyond the fb */
+        if (off > (dev_priv->fb_location + dev_priv->fb_size))
+                off = off - (dev_priv->fb_location + dev_priv->fb_size) +
+                        dev_priv->gart_vm_start;
 
-        return 0;
+        /* Now recheck and fail if out of bounds */
+        if ((off >= dev_priv->fb_location &&
+             off < (dev_priv->fb_location + dev_priv->fb_size)) ||
+            (off >= dev_priv->gart_vm_start &&
+             off < (dev_priv->gart_vm_start + dev_priv->gart_size))) {
+                DRM_DEBUG("offset fixed up to 0x%x\n", off);
+                *offset = off;
+                return 0;
+        }
+        return DRM_ERR(EINVAL);
 }
 
 static __inline__ int radeon_check_and_fixup_packets(drm_radeon_private_t *
@@ -3012,6 +3043,9 @@ static int radeon_cp_setparam(DRM_IOCTL_ARGS)
         case RADEON_SETPARAM_PCIGART_LOCATION:
                 dev_priv->pcigart_offset = sp.value;
                 break;
+        case RADEON_SETPARAM_NEW_MEMMAP:
+                dev_priv->new_memmap = sp.value;
+                break;
         default:
                 DRM_DEBUG("Invalid parameter %d\n", sp.param);
                 return DRM_ERR(EINVAL);