Using the uapi-safe __GENMASK_ULL(), we can stably define the layout of
64-bit packed BVNCs. These defs replace the replicated doc comment that
appears all over the place.
Signed-off-by: Matt Coster <matt.coster@imgtec.com>
---
drivers/gpu/drm/imagination/pvr_device.h | 36 ++++++++++----------------------
include/uapi/drm/pvr_drm.h | 14 ++++++-------
2 files changed, 18 insertions(+), 32 deletions(-)
diff --git a/drivers/gpu/drm/imagination/pvr_device.h b/drivers/gpu/drm/imagination/pvr_device.h
index cfda215e7428..58f0eae05ad9 100644
--- a/drivers/gpu/drm/imagination/pvr_device.h
+++ b/drivers/gpu/drm/imagination/pvr_device.h
@@ -14,7 +14,7 @@
#include <drm/drm_file.h>
#include <drm/drm_mm.h>
-#include <linux/bits.h>
+#include <linux/bitfield.h>
#include <linux/compiler_attributes.h>
#include <linux/compiler_types.h>
#include <linux/device.h>
@@ -479,39 +479,25 @@ struct pvr_file {
* @n: Number of scalable units.
* @c: Config ID.
*
- * The packed layout is as follows:
- *
- * +--------+--------+--------+-------+
- * | 63..48 | 47..32 | 31..16 | 15..0 |
- * +========+========+========+=======+
- * | B | V | N | C |
- * +--------+--------+--------+-------+
+ * The packed layout follows the bitfield defined by the DRM_PVR_BVNC_* macros.
*
* pvr_gpu_id_to_packed_bvnc() should be used instead of this macro when a
* &struct pvr_gpu_id is available in order to ensure proper type checking.
*
* Return: Packed BVNC.
*/
-/* clang-format off */
#define PVR_PACKED_BVNC(b, v, n, c) \
- ((((u64)(b) & GENMASK_ULL(15, 0)) << 48) | \
- (((u64)(v) & GENMASK_ULL(15, 0)) << 32) | \
- (((u64)(n) & GENMASK_ULL(15, 0)) << 16) | \
- (((u64)(c) & GENMASK_ULL(15, 0)) << 0))
-/* clang-format on */
+ (FIELD_PREP(DRM_PVR_BVNC_B, b) | \
+ FIELD_PREP(DRM_PVR_BVNC_V, v) | \
+ FIELD_PREP(DRM_PVR_BVNC_N, n) | \
+ FIELD_PREP(DRM_PVR_BVNC_C, c))
/**
* pvr_gpu_id_to_packed_bvnc() - Packs B, V, N and C values into a 64-bit
* unsigned integer
* @gpu_id: GPU ID.
*
- * The packed layout is as follows:
- *
- * +--------+--------+--------+-------+
- * | 63..48 | 47..32 | 31..16 | 15..0 |
- * +========+========+========+=======+
- * | B | V | N | C |
- * +--------+--------+--------+-------+
+ * The packed layout follows the bitfield defined by the DRM_PVR_BVNC_* macros.
*
* This should be used in preference to PVR_PACKED_BVNC() when a &struct
* pvr_gpu_id is available in order to ensure proper type checking.
@@ -527,10 +513,10 @@ pvr_gpu_id_to_packed_bvnc(const struct pvr_gpu_id *gpu_id)
static __always_inline void
packed_bvnc_to_pvr_gpu_id(u64 bvnc, struct pvr_gpu_id *gpu_id)
{
- gpu_id->b = (bvnc & GENMASK_ULL(63, 48)) >> 48;
- gpu_id->v = (bvnc & GENMASK_ULL(47, 32)) >> 32;
- gpu_id->n = (bvnc & GENMASK_ULL(31, 16)) >> 16;
- gpu_id->c = bvnc & GENMASK_ULL(15, 0);
+ gpu_id->b = FIELD_GET(DRM_PVR_BVNC_B, bvnc);
+ gpu_id->v = FIELD_GET(DRM_PVR_BVNC_V, bvnc);
+ gpu_id->n = FIELD_GET(DRM_PVR_BVNC_N, bvnc);
+ gpu_id->c = FIELD_GET(DRM_PVR_BVNC_C, bvnc);
}
int pvr_device_init(struct pvr_device *pvr_dev);
diff --git a/include/uapi/drm/pvr_drm.h b/include/uapi/drm/pvr_drm.h
index ccf6c2112468..72f3f90560cf 100644
--- a/include/uapi/drm/pvr_drm.h
+++ b/include/uapi/drm/pvr_drm.h
@@ -6,6 +6,7 @@
#include "drm.h"
+#include <linux/bits.h>
#include <linux/const.h>
#include <linux/types.h>
@@ -113,6 +114,11 @@ struct drm_pvr_obj_array {
* DOC: PowerVR IOCTL DEV_QUERY interface
*/
+#define DRM_PVR_BVNC_B __GENMASK_ULL(63, 48)
+#define DRM_PVR_BVNC_V __GENMASK_ULL(47, 32)
+#define DRM_PVR_BVNC_N __GENMASK_ULL(31, 16)
+#define DRM_PVR_BVNC_C __GENMASK_ULL(15, 0)
+
/**
* struct drm_pvr_dev_query_gpu_info - Container used to fetch information about
* the graphics processor.
@@ -125,13 +131,7 @@ struct drm_pvr_dev_query_gpu_info {
* @gpu_id: GPU identifier.
*
* For all currently supported GPUs this is the BVNC encoded as a 64-bit
- * value as follows:
- *
- * +--------+--------+--------+-------+
- * | 63..48 | 47..32 | 31..16 | 15..0 |
- * +========+========+========+=======+
- * | B | V | N | C |
- * +--------+--------+--------+-------+
+ * value using the DRM_PVR_BVNC_* bitmasks.
*/
__u64 gpu_id;
--
2.52.0Hi Matt,
kernel test robot noticed the following build errors:
[auto build test ERROR on 55473b60178060a4fdb4631bd0c91879cc7d18d8]
url: https://github.com/intel-lab-lkp/linux/commits/Matt-Coster/drm-imagination-Define-packed-BVNCs-in-the-uapi/20260206-175844
base: 55473b60178060a4fdb4631bd0c91879cc7d18d8
patch link: https://lore.kernel.org/r/20260206-bvnc-cleanup-v1-1-f3c818541fbe%40imgtec.com
patch subject: [PATCH 1/2] drm/imagination: Define packed BVNCs in the uapi
config: riscv-randconfig-001-20260206 (https://download.01.org/0day-ci/archive/20260207/202602070500.zo0DrH6U-lkp@intel.com/config)
compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project 9b8addffa70cee5b2acc5454712d9cf78ce45710)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260207/202602070500.zo0DrH6U-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202602070500.zo0DrH6U-lkp@intel.com/
All errors (new ones prefixed by >>):
>> drivers/gpu/drm/imagination/pvr_device.c:550:7: error: expression is not an integer constant expression
550 | case PVR_PACKED_BVNC(33, 15, 11, 3):
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/imagination/pvr_device.h:490:2: note: expanded from macro 'PVR_PACKED_BVNC'
490 | (FIELD_PREP(DRM_PVR_BVNC_B, b) | \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
491 | FIELD_PREP(DRM_PVR_BVNC_V, v) | \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
492 | FIELD_PREP(DRM_PVR_BVNC_N, n) | \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
493 | FIELD_PREP(DRM_PVR_BVNC_C, c))
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/imagination/pvr_device.c:550:7: note: this use of statement expressions is not supported in a constant expression
drivers/gpu/drm/imagination/pvr_device.h:490:3: note: expanded from macro 'PVR_PACKED_BVNC'
490 | (FIELD_PREP(DRM_PVR_BVNC_B, b) | \
| ^
include/linux/bitfield.h:137:3: note: expanded from macro 'FIELD_PREP'
137 | __FIELD_PREP(_mask, _val, "FIELD_PREP: "); \
| ^
include/linux/bitfield.h:90:3: note: expanded from macro '__FIELD_PREP'
90 | __BF_FIELD_CHECK_MASK(mask, val, pfx); \
| ^
note: (skipping 4 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
include/linux/compiler_types.h:631:2: note: expanded from macro 'compiletime_assert'
631 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^
include/linux/compiler_types.h:619:2: note: expanded from macro '_compiletime_assert'
619 | __compiletime_assert(condition, msg, prefix, suffix)
| ^
include/linux/compiler_types.h:603:2: note: expanded from macro '__compiletime_assert'
603 | do { \
| ^
drivers/gpu/drm/imagination/pvr_device.c:551:7: error: expression is not an integer constant expression
551 | case PVR_PACKED_BVNC(36, 53, 104, 796):
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/imagination/pvr_device.h:490:2: note: expanded from macro 'PVR_PACKED_BVNC'
490 | (FIELD_PREP(DRM_PVR_BVNC_B, b) | \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
491 | FIELD_PREP(DRM_PVR_BVNC_V, v) | \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
492 | FIELD_PREP(DRM_PVR_BVNC_N, n) | \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
493 | FIELD_PREP(DRM_PVR_BVNC_C, c))
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/imagination/pvr_device.c:551:7: note: this use of statement expressions is not supported in a constant expression
drivers/gpu/drm/imagination/pvr_device.h:490:3: note: expanded from macro 'PVR_PACKED_BVNC'
490 | (FIELD_PREP(DRM_PVR_BVNC_B, b) | \
| ^
include/linux/bitfield.h:137:3: note: expanded from macro 'FIELD_PREP'
137 | __FIELD_PREP(_mask, _val, "FIELD_PREP: "); \
| ^
include/linux/bitfield.h:90:3: note: expanded from macro '__FIELD_PREP'
90 | __BF_FIELD_CHECK_MASK(mask, val, pfx); \
| ^
note: (skipping 4 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
include/linux/compiler_types.h:631:2: note: expanded from macro 'compiletime_assert'
631 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^
include/linux/compiler_types.h:619:2: note: expanded from macro '_compiletime_assert'
619 | __compiletime_assert(condition, msg, prefix, suffix)
| ^
include/linux/compiler_types.h:603:2: note: expanded from macro '__compiletime_assert'
603 | do { \
| ^
drivers/gpu/drm/imagination/pvr_device.c:554:7: error: expression is not an integer constant expression
554 | case PVR_PACKED_BVNC(36, 52, 104, 182):
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/imagination/pvr_device.h:490:2: note: expanded from macro 'PVR_PACKED_BVNC'
490 | (FIELD_PREP(DRM_PVR_BVNC_B, b) | \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
491 | FIELD_PREP(DRM_PVR_BVNC_V, v) | \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
492 | FIELD_PREP(DRM_PVR_BVNC_N, n) | \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
493 | FIELD_PREP(DRM_PVR_BVNC_C, c))
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/imagination/pvr_device.c:554:7: note: this use of statement expressions is not supported in a constant expression
drivers/gpu/drm/imagination/pvr_device.h:490:3: note: expanded from macro 'PVR_PACKED_BVNC'
490 | (FIELD_PREP(DRM_PVR_BVNC_B, b) | \
| ^
include/linux/bitfield.h:137:3: note: expanded from macro 'FIELD_PREP'
137 | __FIELD_PREP(_mask, _val, "FIELD_PREP: "); \
| ^
include/linux/bitfield.h:90:3: note: expanded from macro '__FIELD_PREP'
90 | __BF_FIELD_CHECK_MASK(mask, val, pfx); \
| ^
note: (skipping 4 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
include/linux/compiler_types.h:631:2: note: expanded from macro 'compiletime_assert'
631 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^
include/linux/compiler_types.h:619:2: note: expanded from macro '_compiletime_assert'
619 | __compiletime_assert(condition, msg, prefix, suffix)
| ^
include/linux/compiler_types.h:603:2: note: expanded from macro '__compiletime_assert'
603 | do { \
| ^
3 errors generated.
vim +550 drivers/gpu/drm/imagination/pvr_device.c
1c21f240fbc1e47 Matt Coster 2026-01-13 545
1c21f240fbc1e47 Matt Coster 2026-01-13 546 static enum pvr_gpu_support_level
1c21f240fbc1e47 Matt Coster 2026-01-13 547 pvr_gpu_support_level(const struct pvr_gpu_id *gpu_id)
1c21f240fbc1e47 Matt Coster 2026-01-13 548 {
1c21f240fbc1e47 Matt Coster 2026-01-13 549 switch (pvr_gpu_id_to_packed_bvnc(gpu_id)) {
1c21f240fbc1e47 Matt Coster 2026-01-13 @550 case PVR_PACKED_BVNC(33, 15, 11, 3):
1c21f240fbc1e47 Matt Coster 2026-01-13 551 case PVR_PACKED_BVNC(36, 53, 104, 796):
1c21f240fbc1e47 Matt Coster 2026-01-13 552 return PVR_GPU_SUPPORTED;
1c21f240fbc1e47 Matt Coster 2026-01-13 553
1c21f240fbc1e47 Matt Coster 2026-01-13 554 case PVR_PACKED_BVNC(36, 52, 104, 182):
1c21f240fbc1e47 Matt Coster 2026-01-13 555 return PVR_GPU_EXPERIMENTAL;
1c21f240fbc1e47 Matt Coster 2026-01-13 556
1c21f240fbc1e47 Matt Coster 2026-01-13 557 default:
1c21f240fbc1e47 Matt Coster 2026-01-13 558 return PVR_GPU_UNKNOWN;
1c21f240fbc1e47 Matt Coster 2026-01-13 559 }
1c21f240fbc1e47 Matt Coster 2026-01-13 560 }
1c21f240fbc1e47 Matt Coster 2026-01-13 561
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Hi Matt,
kernel test robot noticed the following build errors:
[auto build test ERROR on 55473b60178060a4fdb4631bd0c91879cc7d18d8]
url: https://github.com/intel-lab-lkp/linux/commits/Matt-Coster/drm-imagination-Define-packed-BVNCs-in-the-uapi/20260206-175844
base: 55473b60178060a4fdb4631bd0c91879cc7d18d8
patch link: https://lore.kernel.org/r/20260206-bvnc-cleanup-v1-1-f3c818541fbe%40imgtec.com
patch subject: [PATCH 1/2] drm/imagination: Define packed BVNCs in the uapi
config: riscv-randconfig-r112-20260206 (https://download.01.org/0day-ci/archive/20260207/202602070204.PjaKNSpZ-lkp@intel.com/config)
compiler: riscv64-linux-gcc (GCC) 10.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260207/202602070204.PjaKNSpZ-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202602070204.PjaKNSpZ-lkp@intel.com/
All errors (new ones prefixed by >>):
drivers/gpu/drm/imagination/pvr_device.c: In function 'pvr_gpu_support_level':
>> drivers/gpu/drm/imagination/pvr_device.c:550:2: error: case label does not reduce to an integer constant
550 | case PVR_PACKED_BVNC(33, 15, 11, 3):
| ^~~~
drivers/gpu/drm/imagination/pvr_device.c:551:2: error: case label does not reduce to an integer constant
551 | case PVR_PACKED_BVNC(36, 53, 104, 796):
| ^~~~
drivers/gpu/drm/imagination/pvr_device.c:554:2: error: case label does not reduce to an integer constant
554 | case PVR_PACKED_BVNC(36, 52, 104, 182):
| ^~~~
vim +550 drivers/gpu/drm/imagination/pvr_device.c
1c21f240fbc1e4 Matt Coster 2026-01-13 545
1c21f240fbc1e4 Matt Coster 2026-01-13 546 static enum pvr_gpu_support_level
1c21f240fbc1e4 Matt Coster 2026-01-13 547 pvr_gpu_support_level(const struct pvr_gpu_id *gpu_id)
1c21f240fbc1e4 Matt Coster 2026-01-13 548 {
1c21f240fbc1e4 Matt Coster 2026-01-13 549 switch (pvr_gpu_id_to_packed_bvnc(gpu_id)) {
1c21f240fbc1e4 Matt Coster 2026-01-13 @550 case PVR_PACKED_BVNC(33, 15, 11, 3):
1c21f240fbc1e4 Matt Coster 2026-01-13 551 case PVR_PACKED_BVNC(36, 53, 104, 796):
1c21f240fbc1e4 Matt Coster 2026-01-13 552 return PVR_GPU_SUPPORTED;
1c21f240fbc1e4 Matt Coster 2026-01-13 553
1c21f240fbc1e4 Matt Coster 2026-01-13 554 case PVR_PACKED_BVNC(36, 52, 104, 182):
1c21f240fbc1e4 Matt Coster 2026-01-13 555 return PVR_GPU_EXPERIMENTAL;
1c21f240fbc1e4 Matt Coster 2026-01-13 556
1c21f240fbc1e4 Matt Coster 2026-01-13 557 default:
1c21f240fbc1e4 Matt Coster 2026-01-13 558 return PVR_GPU_UNKNOWN;
1c21f240fbc1e4 Matt Coster 2026-01-13 559 }
1c21f240fbc1e4 Matt Coster 2026-01-13 560 }
1c21f240fbc1e4 Matt Coster 2026-01-13 561
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
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