Support AGP bridges where the AGP aperture can't be accessed directly by

    the CPU (David Mosberger, Benjamin Herrenschmidt, myself, Paul
    Mackerras, Jeff Wiedemeier)

1 files changed, 159 insertions, 6 deletions

diff --git a/linux-core/drm_memory.h b/linux-core/drm_memory.h
index ae5737f1..5f111459 100644
--- a/linux-core/drm_memory.h
+++ b/linux-core/drm_memory.h
@@ -39,6 +39,159 @@
  */
 #define DEBUG_MEMORY 0
 
+/* Need the 4-argument version of vmap().  */
+#if __REALLY_HAVE_AGP && defined(VMAP_4_ARGS)
+
+#include <linux/vmalloc.h>
+
+#ifdef HAVE_PAGE_AGP
+#include <asm/agp.h>
+#else
+# ifdef __powerpc__
+#  define PAGE_AGP	__pgprot(_PAGE_KERNEL | _PAGE_NO_CACHE)
+# else
+#  define PAGE_AGP	PAGE_KERNEL
+# endif
+#endif
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
+# include <asm/tlbflush.h>
+#else
+# define pte_offset_kernel(dir, address)	pte_offset(dir, address)
+# define pte_pfn(pte)				(pte_page(pte) - mem_map)
+# define pfn_to_page(pfn)			(mem_map + (pfn))
+# define flush_tlb_kernel_range(s,e)		flush_tlb_all()
+#endif
+
+/*
+ * Find the drm_map that covers the range [offset, offset+size).
+ */
+static inline drm_map_t *
+drm_lookup_map (unsigned long offset, unsigned long size, drm_device_t *dev)
+{
+	struct list_head *list;
+	drm_map_list_t *r_list;
+	drm_map_t *map;
+
+	list_for_each(list, &dev->maplist->head) {
+		r_list = (drm_map_list_t *) list;
+		map = r_list->map;
+		if (!map)
+			continue;
+		if (map->offset <= offset && (offset + size) <= (map->offset + map->size))
+			return map;
+	}
+	return NULL;
+}
+
+static inline void *
+agp_remap (unsigned long offset, unsigned long size, drm_device_t *dev)
+{
+	unsigned long *phys_addr_map, i, num_pages = PAGE_ALIGN(size) / PAGE_SIZE;
+	struct drm_agp_mem *agpmem;
+	struct page **page_map;
+	void *addr;
+
+	size = PAGE_ALIGN(size);
+
+#ifdef __alpha__
+	offset -= dev->hose->mem_space->start;
+#endif
+
+	for (agpmem = dev->agp->memory; agpmem; agpmem = agpmem->next)
+		if (agpmem->bound <= offset
+		    && (agpmem->bound + (agpmem->pages << PAGE_SHIFT)) >= (offset + size))
+			break;
+	if (!agpmem)
+		return NULL;
+
+	/*
+	 * OK, we're mapping AGP space on a chipset/platform on which memory accesses by
+	 * the CPU do not get remapped by the GART.  We fix this by using the kernel's
+	 * page-table instead (that's probably faster anyhow...).
+	 */
+	/* note: use vmalloc() because num_pages could be large... */
+	page_map = vmalloc(num_pages * sizeof(struct page *));
+	if (!page_map)
+		return NULL;
+
+	phys_addr_map = agpmem->memory->memory + (offset - agpmem->bound) / PAGE_SIZE;
+	for (i = 0; i < num_pages; ++i)
+		page_map[i] = pfn_to_page(phys_addr_map[i] >> PAGE_SHIFT);
+	addr = vmap(page_map, num_pages, VM_IOREMAP, PAGE_AGP);
+	vfree(page_map);
+	if (!addr)
+		return NULL;
+
+	flush_tlb_kernel_range((unsigned long) addr, (unsigned long) addr + size);
+	return addr;
+}
+
+static inline unsigned long
+drm_follow_page (void *vaddr)
+{
+	pgd_t *pgd = pgd_offset_k((unsigned long) vaddr);
+	pmd_t *pmd = pmd_offset(pgd, (unsigned long) vaddr);
+	pte_t *ptep = pte_offset_kernel(pmd, (unsigned long) vaddr);
+	return pte_pfn(*ptep) << PAGE_SHIFT;
+}
+
+#endif /* __REALLY_HAVE_AGP && defined(VMAP_4_ARGS) */
+
+static inline void *drm_ioremap(unsigned long offset, unsigned long size, drm_device_t *dev)
+{
+#if __REALLY_HAVE_AGP && defined(VMAP_4_ARGS)
+	if (dev->agp && dev->agp->cant_use_aperture) {
+		drm_map_t *map = drm_lookup_map(offset, size, dev);
+
+		if (map && map->type == _DRM_AGP)
+			return agp_remap(offset, size, dev);
+	}
+#endif
+
+	return ioremap(offset, size);
+}
+
+static inline void *drm_ioremap_nocache(unsigned long offset, unsigned long size,
+					drm_device_t *dev)
+{
+#if __REALLY_HAVE_AGP && defined(VMAP_4_ARGS)
+	if (dev->agp && dev->agp->cant_use_aperture) {
+		drm_map_t *map = drm_lookup_map(offset, size, dev);
+
+		if (map && map->type == _DRM_AGP)
+			return agp_remap(offset, size, dev);
+	}
+#endif
+
+	return ioremap_nocache(offset, size);
+}
+
+static inline void drm_ioremapfree(void *pt, unsigned long size, drm_device_t *dev)
+{
+#if __REALLY_HAVE_AGP && defined(VMAP_4_ARGS)
+	/*
+	 * This is a bit ugly.  It would be much cleaner if the DRM API would use separate
+	 * routines for handling mappings in the AGP space.  Hopefully this can be done in
+	 * a future revision of the interface...
+	 */
+	if (dev->agp && dev->agp->cant_use_aperture
+	    && ((unsigned long) pt >= VMALLOC_START && (unsigned long) pt < VMALLOC_END))
+	{
+		unsigned long offset;
+		drm_map_t *map;
+
+		offset = drm_follow_page(pt) | ((unsigned long) pt & ~PAGE_MASK);
+		map = drm_lookup_map(offset, size, dev);
+		if (map && map->type == _DRM_AGP) {
+			vunmap(pt);
+			return;
+		}
+	}
+#endif
+
+	iounmap(pt);
+}
 
 #if DEBUG_MEMORY
 #include "drm_memory_debug.h"
@@ -119,19 +272,19 @@ void DRM(free_pages)(unsigned long address, int order, int area)
 	free_pages(address, order);
 }
 
-void *DRM(ioremap)(unsigned long offset, unsigned long size)
+void *DRM(ioremap)(unsigned long offset, unsigned long size, drm_device_t *dev)
 {
-	return ioremap(offset, size);
+	return drm_ioremap(offset, size, dev);
 }
 
-void *DRM(ioremap_nocache)(unsigned long offset, unsigned long size)
+void *DRM(ioremap_nocache)(unsigned long offset, unsigned long size, drm_device_t *dev)
 {
-	return ioremap_nocache(offset, size);
+	return drm_ioremap_nocache(offset, size, dev);
 }
 
-void DRM(ioremapfree)(void *pt, unsigned long size)
+void DRM(ioremapfree)(void *pt, unsigned long size, drm_device_t *dev)
 {
-	iounmap(pt);
+	drm_ioremapfree(pt, size, dev);
 }
 
 #if __REALLY_HAVE_AGP