sm501: fixup allocation code to be 64bit resource compliant

As pointed out by Andrew Morton, we have a problem when setting the 64bit
resources option.  Alter the allocation routines to remove the need to use
the start and end fields, use the proper HEAD_PANEL/HEAD_CRT and update
the comments.

Note, we also fix the bug where we failed to check the size of the
CRT memory allocation.

[akpm@linux-foundation.org: cleanup]
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 42 insertions, 11 deletions

diff --git a/drivers/video/sm501fb.c b/drivers/video/sm501fb.c
index b473cf665d83..f94ae84a58cd 100644
--- a/drivers/video/sm501fb.c
+++ b/drivers/video/sm501fb.c
@@ -48,10 +48,15 @@ enum sm501_controller {
         HEAD_PANEL      = 1,
 };
 
-/* SM501 memory address */
+/* SM501 memory address.
+ *
+ * This structure is used to track memory usage within the SM501 framebuffer
+ * allocation. The sm_addr field is stored as an offset as it is often used
+ * against both the physical and mapped addresses.
+ */
 struct sm501_mem {
         unsigned long    size;
-        unsigned long    sm_addr;
+        unsigned long    sm_addr;       /* offset from base of sm501 fb. */
         void __iomem    *k_addr;
 };
 
@@ -142,37 +147,63 @@ static inline void sm501fb_sync_regs(struct sm501fb_info *info)
 static int sm501_alloc_mem(struct sm501fb_info *inf, struct sm501_mem *mem,
                            unsigned int why, size_t size)
 {
-        unsigned int ptr = 0;
-        unsigned int end;
+        struct sm501fb_par *par;
         struct fb_info *fbi;
+        unsigned int ptr;
+        unsigned int end;
 
         switch (why) {
         case SM501_MEMF_CURSOR:
                 ptr = inf->fbmem_len - size;
-                inf->fbmem_len = ptr;
+                inf->fbmem_len = ptr;   /* adjust available memory. */
                 break;
 
         case SM501_MEMF_PANEL:
                 ptr = inf->fbmem_len - size;
-                fbi = inf->fb[0];
+                fbi = inf->fb[HEAD_CRT];
+
+                /* round down, some programs such as directfb do not draw
+                 * 0,0 correctly unless the start is aligned to a page start.
+                 */
+
+                if (ptr > 0)
+                        ptr &= ~(PAGE_SIZE - 1);
 
                 if (fbi && ptr < fbi->fix.smem_len)
                         return -ENOMEM;
 
+                if (ptr < 0)
+                        return -ENOMEM;
+
                 break;
 
         case SM501_MEMF_CRT:
                 ptr = 0;
+
+                /* check to see if we have panel memory allocated
+                 * which would put an limit on available memory. */
+
+                fbi = inf->fb[HEAD_PANEL];
+                if (fbi) {
+                        par = fbi->par;
+                        end = par->screen.k_addr ? par->screen.sm_addr : inf->fbmem_len;
+                } else
+                        end = inf->fbmem_len;
+
+                if ((ptr + size) > end)
+                        return -ENOMEM;
+
                 break;
 
         case SM501_MEMF_ACCEL:
-                fbi = inf->fb[0];
+                fbi = inf->fb[HEAD_CRT];
                 ptr = fbi ? fbi->fix.smem_len : 0;
 
-                fbi = inf->fb[1];
-                if (fbi)
-                        end = (fbi->fix.smem_start - inf->fbmem_res->start);
-                else
+                fbi = inf->fb[HEAD_PANEL];
+                if (fbi) {
+                        par = fbi->par;
+                        end = par->screen.sm_addr;
+                } else
                         end = inf->fbmem_len;
 
                 if ((ptr + size) > end)