drm/i915/gen8: Make pdp allocation more dynamic

This transitional patch doesn't do much for the existing code. However,
it should make upcoming patches to use the full 48b address space a bit
easier.

32-bit ppgtt uses just 4 PDPs, while 48-bit ppgtt will have up-to 512;
this patch prepares the existing functions to query the right number of pdps
at run-time. This also means that used_pdpes should also be allocated during
ppgtt_init, as the bitmap size will depend on the ppgtt address range
selected.

v2: Renamed  pdp_free to be similar to  pd/pt (unmap_and_free_pdp).
v3: To facilitate testing, 48b mode will be available on Broadwell and
GEN9+, when i915.enable_ppgtt = 3.
v4: Rebase after s/page_tables/page_table/, added extra information
about 4-level page table formats and use IS_ENABLED macro.
v5: Check CONFIG_X86_64 instead of CONFIG_64BIT.
v6: Rebase after Mika's ppgtt cleanup / scratch merge patch series, and
follow
his nomenclature in pdp functions (there is no alloc_pdp yet).
v7: Rebase after merged version of Mika's ppgtt cleanup patch series.
v8: Rebase after final merged version of Mika's ppgtt/scratch patches.
v9: Introduce PML4 (and 48-bit checks) until next patch (Akash).
v10: Also use test_bit to detect when pd/pt are already allocated (Akash)

Cc: Akash Goel <akash.goel@intel.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Michel Thierry <michel.thierry@intel.com> (v2+)
Reviewed-by: Akash Goel <akash.goel@intel.com>
[danvet: Amend commit message as suggested by Michel.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 11 insertions, 6 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
index d5bf953deff9..87e389c6c9c0 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.h
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
@@ -98,6 +98,9 @@ typedef uint64_t gen8_pde_t;
 #define GEN8_LEGACY_PDPES		4
 #define GEN8_PTES			I915_PTES(sizeof(gen8_pte_t))
 
+/* FIXME: Next patch will use dev */
+#define I915_PDPES_PER_PDP(dev)		GEN8_LEGACY_PDPES
+
 #define PPAT_UNCACHED_INDEX		(_PAGE_PWT | _PAGE_PCD)
 #define PPAT_CACHED_PDE_INDEX		0 /* WB LLC */
 #define PPAT_CACHED_INDEX		_PAGE_PAT /* WB LLCeLLC */
@@ -241,9 +244,10 @@ struct i915_page_directory {
 };
 
 struct i915_page_directory_pointer {
-	/* struct page *page; */
-	DECLARE_BITMAP(used_pdpes, GEN8_LEGACY_PDPES);
-	struct i915_page_directory *page_directory[GEN8_LEGACY_PDPES];
+	struct i915_page_dma base;
+
+	unsigned long *used_pdpes;
+	struct i915_page_directory **page_directory;
 };
 
 struct i915_address_space {
@@ -436,9 +440,10 @@ static inline uint32_t gen6_pde_index(uint32_t addr)
 	     temp = min(temp, length),					\
 	     start += temp, length -= temp)
 
-#define gen8_for_each_pdpe(pd, pdp, start, length, temp, iter)		\
-	for (iter = gen8_pdpe_index(start);	\
-	     pd = (pdp)->page_directory[iter], length > 0 && iter < GEN8_LEGACY_PDPES;	\
+#define gen8_for_each_pdpe(pd, pdp, start, length, temp, iter)	\
+	for (iter = gen8_pdpe_index(start); \
+	     pd = (pdp)->page_directory[iter], \
+	     length > 0 && (iter < I915_PDPES_PER_PDP(dev)); \
 	     iter++,				\
 	     temp = ALIGN(start+1, 1 << GEN8_PDPE_SHIFT) - start,	\
 	     temp = min(temp, length),					\