[RFC 3/4] drm/nouveau: use format modifier helper funcs

[James Jones]

When parsing the parameteric NVIDIA block-linear
format modifiers to determine surface tiling
attributes, use the new helper functions to
extract values from various fields. This avoids
using magic values to extract the bitfields from
the modifier, which makes the code more readable.

Signed-off-by: James Jones <jajones at nvidia.com>
---
 drivers/gpu/drm/nouveau/nouveau_display.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_display.c b/drivers/gpu/drm/nouveau/nouveau_display.c
index add006fc8d81..1bec664a2b67 100644
--- a/drivers/gpu/drm/nouveau/nouveau_display.c
+++ b/drivers/gpu/drm/nouveau/nouveau_display.c
@@ -146,14 +146,18 @@ nouveau_decode_mod(struct nouveau_drm *drm,
 		 * Extract the block height and kind from the corresponding
 		 * modifier fields.  See drm_fourcc.h for details.
 		 */
+		uint64_t pkind = drm_fourcc_nvidia_format_mod_pkind(modifier);
 
-		if ((modifier & (0xffull << 12)) == 0ull) {
+		if (pkind == 0ull) {
 			/* Legacy modifier.  Translate to this dev's 'kind.' */
-			modifier |= disp->format_modifiers[0] & (0xffull << 12);
+			const uint64_t any_dev_mod = disp->format_modifiers[0];
+
+			pkind = drm_fourcc_nvidia_format_mod_pkind(any_dev_mod);
 		}
 
-		*tile_mode = (uint32_t)(modifier & 0xF);
-		*kind = (uint8_t)((modifier >> 12) & 0xFF);
+		*tile_mode =
+			(uint32_t)drm_fourcc_nvidia_format_mod_l2gpbh(modifier);
+		*kind = (uint8_t)pkind;
 
 		if (drm->client.device.info.chipset >= 0xc0)
 			*tile_mode <<= 4;
-- 
2.49.0