uvesafb: Clean up MTRR code

The old code allowed very strange memory types.  Now it works like
all the other video drivers: ioremap_wc is used unconditionally,
and MTRRs are set if PAT is unavailable (unless MTRR is disabled
by a module parameter).

UC, WB, and WT support is gone.  If there are MTRR conflicts that prevent
addition of a WC MTRR, adding a non-conflicting MTRR is pointless; it's
better to just turn off MTRR support entirely.

As an added bonus, any MTRR added is freed on unload.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 17 insertions, 53 deletions

diff --git a/drivers/video/uvesafb.c b/drivers/video/uvesafb.c
index e328a61b64ba..296279bc71d2 100644
--- a/drivers/video/uvesafb.c
+++ b/drivers/video/uvesafb.c
@@ -24,9 +24,6 @@
 #ifdef CONFIG_X86
 #include <video/vga.h>
 #endif
-#ifdef CONFIG_MTRR
-#include <asm/mtrr.h>
-#endif
 #include "edid.h"
 
 static struct cb_id uvesafb_cn_id = {
@@ -1540,67 +1537,30 @@ static void uvesafb_init_info(struct fb_info *info, struct vbe_mode_ib *mode)
 
 static void uvesafb_init_mtrr(struct fb_info *info)
 {
-#ifdef CONFIG_MTRR
+        struct uvesafb_par *par = info->par;
+
         if (mtrr && !(info->fix.smem_start & (PAGE_SIZE - 1))) {
                 int temp_size = info->fix.smem_len;
-                unsigned int type = 0;
 
-                switch (mtrr) {
-                case 1:
-                        type = MTRR_TYPE_UNCACHABLE;
-                        break;
-                case 2:
-                        type = MTRR_TYPE_WRBACK;
-                        break;
-                case 3:
-                        type = MTRR_TYPE_WRCOMB;
-                        break;
-                case 4:
-                        type = MTRR_TYPE_WRTHROUGH;
-                        break;
-                default:
-                        type = 0;
-                        break;
-                }
+                int rc;
 
-                if (type) {
-                        int rc;
+                /* Find the largest power-of-two */
+                temp_size = roundup_pow_of_two(temp_size);
 
-                        /* Find the largest power-of-two */
-                        temp_size = roundup_pow_of_two(temp_size);
+                /* Try and find a power of two to add */
+                do {
+                        rc = arch_phys_wc_add(info->fix.smem_start, temp_size);
+                        temp_size >>= 1;
+                } while (temp_size >= PAGE_SIZE && rc == -EINVAL);
 
-                        /* Try and find a power of two to add */
-                        do {
-                                rc = mtrr_add(info->fix.smem_start,
-                                              temp_size, type, 1);
-                                temp_size >>= 1;
-                        } while (temp_size >= PAGE_SIZE && rc == -EINVAL);
-                }
+                if (rc >= 0)
+                        par->mtrr_handle = rc;
         }
-#endif /* CONFIG_MTRR */
 }
 
 static void uvesafb_ioremap(struct fb_info *info)
 {
-#ifdef CONFIG_X86
-        switch (mtrr) {
-        case 1: /* uncachable */
-                info->screen_base = ioremap_nocache(info->fix.smem_start, info->fix.smem_len);
-                break;
-        case 2: /* write-back */
-                info->screen_base = ioremap_cache(info->fix.smem_start, info->fix.smem_len);
-                break;
-        case 3: /* write-combining */
-                info->screen_base = ioremap_wc(info->fix.smem_start, info->fix.smem_len);
-                break;
-        case 4: /* write-through */
-        default:
-                info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);
-                break;
-        }
-#else
-        info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);
-#endif /* CONFIG_X86 */
+        info->screen_base = ioremap_wc(info->fix.smem_start, info->fix.smem_len);
 }
 
 static ssize_t uvesafb_show_vbe_ver(struct device *dev,
@@ -1851,6 +1811,7 @@ static int uvesafb_remove(struct platform_device *dev)
                 unregister_framebuffer(info);
                 release_region(0x3c0, 32);
                 iounmap(info->screen_base);
+                arch_phys_wc_del(par->mtrr_handle);
                 release_mem_region(info->fix.smem_start, info->fix.smem_len);
                 fb_destroy_modedb(info->monspecs.modedb);
                 fb_dealloc_cmap(&info->cmap);
@@ -1930,6 +1891,9 @@ static int uvesafb_setup(char *options)
                 }
         }
 
+        if (mtrr != 3 && mtrr != 1)
+                pr_warn("uvesafb: mtrr should be set to 0 or 3; %d is unsupported", mtrr);
+
         return 0;
 }
 #endif /* !MODULE */