drm: rip out drm_core_has_MTRR checks

The new arch_phys_wc_add/del functions do the right thing both with
and without MTRR support in the kernel. So we can drop these
additional checks.

David Herrmann suggest to also kill the DRIVER_USE_MTRR flag since
it's now unused, which spurred me to do a bit a better audit of the
affected drivers. David helped a lot in that. Quoting our mail
discussion:

On Wed, Jul 10, 2013 at 5:41 PM, David Herrmann <dh.herrmann@gmail.com> wrote:
> On Wed, Jul 10, 2013 at 5:22 PM, Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
>> On Wed, Jul 10, 2013 at 3:51 PM, David Herrmann <dh.herrmann@gmail.com> wrote:
>>>> -#if __OS_HAS_MTRR
>>>> -static inline int drm_core_has_MTRR(struct drm_device *dev)
>>>> -{
>>>> -       return drm_core_check_feature(dev, DRIVER_USE_MTRR);
>>>> -}
>>>> -#else
>>>> -#define drm_core_has_MTRR(dev) (0)
>>>> -#endif
>>>> -
>>>
>>> That was the last user of DRIVER_USE_MTRR (apart from drivers setting
>>> it in .driver_features). Any reason to keep it around?
>>
>> Yeah, I guess we could rip things out. Which will also force me to
>> properly audit drivers for the eventual behaviour change this could
>> entail (in case there's an x86 driver which did not ask for an mtrr,
>> but iirc there isn't).
>
> david@david-mb ~/dev/kernel/linux $ for i in drivers/gpu/drm/* ; do if
> test -d "$i" ; then if ! grep -q USE_MTRR -r $i ; then echo $i ; fi ;
> fi ; done
> drivers/gpu/drm/exynos
> drivers/gpu/drm/gma500
> drivers/gpu/drm/i2c
> drivers/gpu/drm/nouveau
> drivers/gpu/drm/omapdrm
> drivers/gpu/drm/qxl
> drivers/gpu/drm/rcar-du
> drivers/gpu/drm/shmobile
> drivers/gpu/drm/tilcdc
> drivers/gpu/drm/ttm
> drivers/gpu/drm/udl
> drivers/gpu/drm/vmwgfx
> david@david-mb ~/dev/kernel/linux $
>
> So for x86 gma500,nouveau,qxl,udl,vmwgfx don't set DRIVER_USE_MTRR.
> But I cannot tell whether they break if we call arch_phys_wc_add/del,
> anyway. At least nouveau seemed to work here, but it doesn't use AGP
> or drm_bufs, I guess.

Cool, thanks a lot for stitching together the list of drivers to look
at. So for real KMS drivers it's the drives responsibility to add an
mtrr if it needs one. nouvea, radeon, mgag200, i915 and vmwgfx do that
already. Somehow the savage driver also ends up doing that, I have no
idea why.

Note that gma500 as a pure KMS driver doesn't need MTRR setup since
the platforms that it supports all support PAT. So no MTRRs needed to
get wc iomappings.

The mtrr support in the drm core is all for legacy mappings of garts,
framebuffers and registers. All legacy drivers set the USE_MTRR flag,
so we're good there.

All in all I think we can really just ditch this

/endquote

v2: Also kill DRIVER_USE_MTRR as suggested by David Herrmann

v3: Rebase on top of David Herrmann's agp setup/cleanup changes.

Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/ast/ast_drv.c

@@ -197,7 +197,7 @@ static const struct file_operations ast_fops = {
 };
 
 static struct drm_driver driver = {
-	.driver_features = DRIVER_USE_MTRR | DRIVER_MODESET | DRIVER_GEM,
+	.driver_features = DRIVER_MODESET | DRIVER_GEM,
 	.dev_priv_size = 0,
 
 	.load = ast_driver_load,

drivers/gpu/drm/cirrus/cirrus_drv.c

@@ -87,7 +87,7 @@ static const struct file_operations cirrus_driver_fops = {
 #endif
 };
 static struct drm_driver driver = {
-	.driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_USE_MTRR,
+	.driver_features = DRIVER_MODESET | DRIVER_GEM,
 	.load = cirrus_driver_load,
 	.unload = cirrus_driver_unload,
 	.fops = &cirrus_driver_fops,

drivers/gpu/drm/drm_bufs.c

@@ -207,12 +207,10 @@ static int drm_addmap_core(struct drm_device * dev, resource_size_t offset,
 			return 0;
 		}
 
-		if (drm_core_has_MTRR(dev)) {
-			if (map->type == _DRM_FRAME_BUFFER ||
-			    (map->flags & _DRM_WRITE_COMBINING)) {
-				map->mtrr =
-					arch_phys_wc_add(map->offset, map->size);
-			}
+		if (map->type == _DRM_FRAME_BUFFER ||
+		    (map->flags & _DRM_WRITE_COMBINING)) {
+			map->mtrr =
+				arch_phys_wc_add(map->offset, map->size);
 		}
 		if (map->type == _DRM_REGISTERS) {
 			if (map->flags & _DRM_WRITE_COMBINING)
@@ -464,8 +462,7 @@ int drm_rmmap_locked(struct drm_device *dev, struct drm_local_map *map)
 		iounmap(map->handle);
 		/* FALLTHROUGH */
 	case _DRM_FRAME_BUFFER:
-		if (drm_core_has_MTRR(dev))
-			arch_phys_wc_del(map->mtrr);
+		arch_phys_wc_del(map->mtrr);
 		break;
 	case _DRM_SHM:
 		vfree(map->handle);

drivers/gpu/drm/drm_pci.c

@@ -272,12 +272,11 @@ static int drm_pci_agp_init(struct drm_device *dev)
 			DRM_ERROR("Cannot initialize the agpgart module.\n");
 			return -EINVAL;
 		}
-		if (drm_core_has_MTRR(dev)) {
-			if (dev->agp)
-				dev->agp->agp_mtrr = arch_phys_wc_add(
-					dev->agp->agp_info.aper_base,
-					dev->agp->agp_info.aper_size *
-					1024 * 1024);
+		if (dev->agp) {
+			dev->agp->agp_mtrr = arch_phys_wc_add(
+				dev->agp->agp_info.aper_base,
+				dev->agp->agp_info.aper_size *
+				1024 * 1024);
 		}
 	}
 	return 0;
@@ -286,8 +285,7 @@ static int drm_pci_agp_init(struct drm_device *dev)
 static void drm_pci_agp_destroy(struct drm_device *dev)
 {
 	if (drm_core_has_AGP(dev) && dev->agp) {
-		if (drm_core_has_MTRR(dev))
-			arch_phys_wc_del(dev->agp->agp_mtrr);
+		arch_phys_wc_del(dev->agp->agp_mtrr);
 		drm_agp_clear(dev);
 		drm_agp_destroy(dev->agp);
 		dev->agp = NULL;

drivers/gpu/drm/drm_vm.c

@@ -251,8 +251,7 @@ static void drm_vm_shm_close(struct vm_area_struct *vma)
 			switch (map->type) {
 			case _DRM_REGISTERS:
 			case _DRM_FRAME_BUFFER:
-				if (drm_core_has_MTRR(dev))
-					arch_phys_wc_del(map->mtrr);
+				arch_phys_wc_del(map->mtrr);
 				iounmap(map->handle);
 				break;
 			case _DRM_SHM:

drivers/gpu/drm/i810/i810_drv.c

@@ -57,7 +57,7 @@ static const struct file_operations i810_driver_fops = {
 
 static struct drm_driver driver = {
 	.driver_features =
-	    DRIVER_USE_AGP | DRIVER_REQUIRE_AGP | DRIVER_USE_MTRR |
+	    DRIVER_USE_AGP | DRIVER_REQUIRE_AGP |
 	    DRIVER_HAVE_DMA,
 	.dev_priv_size = sizeof(drm_i810_buf_priv_t),
 	.load = i810_driver_load,

drivers/gpu/drm/i915/i915_drv.c

@@ -1006,7 +1006,7 @@ static struct drm_driver driver = {
 	 * deal with them for Intel hardware.
 	 */
 	.driver_features =
-	    DRIVER_USE_AGP | DRIVER_REQUIRE_AGP | /* DRIVER_USE_MTRR |*/
+	    DRIVER_USE_AGP | DRIVER_REQUIRE_AGP |
 	    DRIVER_HAVE_IRQ | DRIVER_IRQ_SHARED | DRIVER_GEM | DRIVER_PRIME,
 	.load = i915_driver_load,
 	.unload = i915_driver_unload,

drivers/gpu/drm/mga/mga_drv.c

@@ -58,7 +58,7 @@ static const struct file_operations mga_driver_fops = {
 
 static struct drm_driver driver = {
 	.driver_features =
-	    DRIVER_USE_AGP | DRIVER_USE_MTRR | DRIVER_PCI_DMA |
+	    DRIVER_USE_AGP | DRIVER_PCI_DMA |
 	    DRIVER_HAVE_DMA | DRIVER_HAVE_IRQ | DRIVER_IRQ_SHARED,
 	.dev_priv_size = sizeof(drm_mga_buf_priv_t),
 	.load = mga_driver_load,

drivers/gpu/drm/mgag200/mgag200_drv.c

@@ -88,7 +88,7 @@ static const struct file_operations mgag200_driver_fops = {
 };
 
 static struct drm_driver driver = {
-	.driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_USE_MTRR,
+	.driver_features = DRIVER_GEM | DRIVER_MODESET,
 	.load = mgag200_driver_load,
 	.unload = mgag200_driver_unload,
 	.fops = &mgag200_driver_fops,

drivers/gpu/drm/r128/r128_drv.c

@@ -56,7 +56,7 @@ static const struct file_operations r128_driver_fops = {
 
 static struct drm_driver driver = {
 	.driver_features =
-	    DRIVER_USE_AGP | DRIVER_USE_MTRR | DRIVER_PCI_DMA | DRIVER_SG |
+	    DRIVER_USE_AGP | DRIVER_PCI_DMA | DRIVER_SG |
 	    DRIVER_HAVE_DMA | DRIVER_HAVE_IRQ | DRIVER_IRQ_SHARED,
 	.dev_priv_size = sizeof(drm_r128_buf_priv_t),
 	.load = r128_driver_load,

drivers/gpu/drm/radeon/radeon_drv.c

@@ -275,7 +275,7 @@ static const struct file_operations radeon_driver_old_fops = {
 
 static struct drm_driver driver_old = {
 	.driver_features =
-	    DRIVER_USE_AGP | DRIVER_USE_MTRR | DRIVER_PCI_DMA | DRIVER_SG |
+	    DRIVER_USE_AGP | DRIVER_PCI_DMA | DRIVER_SG |
 	    DRIVER_HAVE_IRQ | DRIVER_HAVE_DMA | DRIVER_IRQ_SHARED,
 	.dev_priv_size = sizeof(drm_radeon_buf_priv_t),
 	.load = radeon_driver_load,
@@ -382,7 +382,7 @@ static const struct file_operations radeon_driver_kms_fops = {
 
 static struct drm_driver kms_driver = {
 	.driver_features =
-	    DRIVER_USE_AGP | DRIVER_USE_MTRR | 
+	    DRIVER_USE_AGP |
 	    DRIVER_HAVE_IRQ | DRIVER_IRQ_SHARED | DRIVER_GEM |
 	    DRIVER_PRIME,
 	.dev_priv_size = 0,

drivers/gpu/drm/savage/savage_drv.c

@@ -50,7 +50,7 @@ static const struct file_operations savage_driver_fops = {
 
 static struct drm_driver driver = {
 	.driver_features =
-	    DRIVER_USE_AGP | DRIVER_USE_MTRR | DRIVER_HAVE_DMA | DRIVER_PCI_DMA,
+	    DRIVER_USE_AGP | DRIVER_HAVE_DMA | DRIVER_PCI_DMA,
 	.dev_priv_size = sizeof(drm_savage_buf_priv_t),
 	.load = savage_driver_load,
 	.firstopen = savage_driver_firstopen,

drivers/gpu/drm/sis/sis_drv.c

@@ -102,7 +102,7 @@ void sis_driver_postclose(struct drm_device *dev, struct drm_file *file)
 }
 
 static struct drm_driver driver = {
-	.driver_features = DRIVER_USE_AGP | DRIVER_USE_MTRR,
+	.driver_features = DRIVER_USE_AGP,
 	.load = sis_driver_load,
 	.unload = sis_driver_unload,
 	.open = sis_driver_open,

drivers/gpu/drm/tdfx/tdfx_drv.c

@@ -55,7 +55,6 @@ static const struct file_operations tdfx_driver_fops = {
 };
 
 static struct drm_driver driver = {
-	.driver_features = DRIVER_USE_MTRR,
 	.fops = &tdfx_driver_fops,
 	.name = DRIVER_NAME,
 	.desc = DRIVER_DESC,

drivers/gpu/drm/via/via_drv.c

@@ -72,7 +72,7 @@ static const struct file_operations via_driver_fops = {
 
 static struct drm_driver driver = {
 	.driver_features =
-	    DRIVER_USE_AGP | DRIVER_USE_MTRR | DRIVER_HAVE_IRQ |
+	    DRIVER_USE_AGP | DRIVER_HAVE_IRQ |
 	    DRIVER_IRQ_SHARED,
 	.load = via_driver_load,
 	.unload = via_driver_unload,

include/drm/drmP.h

@@ -74,7 +74,6 @@
 #include <linux/idr.h>
 
 #define __OS_HAS_AGP (defined(CONFIG_AGP) || (defined(CONFIG_AGP_MODULE) && defined(MODULE)))
-#define __OS_HAS_MTRR (defined(CONFIG_MTRR))
 
 struct module;
 
@@ -139,7 +138,6 @@ int drm_err(const char *func, const char *format, ...);
 /* driver capabilities and requirements mask */
 #define DRIVER_USE_AGP     0x1
 #define DRIVER_REQUIRE_AGP 0x2
-#define DRIVER_USE_MTRR    0x4
 #define DRIVER_PCI_DMA     0x8
 #define DRIVER_SG          0x10
 #define DRIVER_HAVE_DMA    0x20
@@ -1216,15 +1214,6 @@ static inline int drm_dev_to_irq(struct drm_device *dev)
 	return dev->driver->bus->get_irq(dev);
 }
 
-#if __OS_HAS_MTRR
-static inline int drm_core_has_MTRR(struct drm_device *dev)
-{
-	return drm_core_check_feature(dev, DRIVER_USE_MTRR);
-}
-#else
-#define drm_core_has_MTRR(dev) (0)
-#endif
-
 static inline void drm_device_set_unplugged(struct drm_device *dev)
 {
 	smp_wmb();