From: Thierry Reding treding@nvidia.com
The semantics of do_div() are (see include/asm-generic/div64.h):
uint32_t do_div(uint64_t *n, uint32_t base)
Using a different type will therefore cause the following warning (as seen on xtensa/allmodconfig):
CC [M] drivers/gpu/drm/nouveau/core/subdev/clock/gk20a.o In file included from arch/xtensa/include/generated/asm/div64.h:1:0, from include/linux/kernel.h:124, from include/linux/list.h:8, from include/linux/preempt.h:10, from include/linux/spinlock.h:50, from include/linux/mmzone.h:7, from include/linux/gfp.h:5, from include/linux/slab.h:14, from drivers/gpu/drm/nouveau/core/os.h:5, from drivers/gpu/drm/nouveau/core/include/core/object.h:4, from drivers/gpu/drm/nouveau/core/include/core/device.h:4, from drivers/gpu/drm/nouveau/core/include/subdev/clock.h:4, from drivers/gpu/drm/nouveau/core/subdev/clock/gk20a.c:90: drivers/gpu/drm/nouveau/core/subdev/clock/gk20a.c: In function 'gk20a_pllg_calc_rate': include/asm-generic/div64.h:43:28: warning: comparison of distinct pointer types lacks a cast (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \ ^ drivers/gpu/drm/nouveau/core/subdev/clock/gk20a.c:146:2: note: in expansion of macro 'do_div' do_div(rate, divider); ^ drivers/gpu/drm/nouveau/core/subdev/clock/gk20a.c:146:2: warning: right shift count >= width of type In file included from arch/xtensa/include/generated/asm/div64.h:1:0, from include/linux/kernel.h:124, from include/linux/list.h:8, from include/linux/preempt.h:10, from include/linux/spinlock.h:50, from include/linux/mmzone.h:7, from include/linux/gfp.h:5, from include/linux/slab.h:14, from drivers/gpu/drm/nouveau/core/os.h:5, from drivers/gpu/drm/nouveau/core/include/core/object.h:4, from drivers/gpu/drm/nouveau/core/include/core/device.h:4, from drivers/gpu/drm/nouveau/core/include/subdev/clock.h:4, from drivers/gpu/drm/nouveau/core/subdev/clock/gk20a.c:90: include/asm-generic/div64.h:48:11: warning: passing argument 1 of '__div64_32' from incompatible pointer type __rem = __div64_32(&(n), __base); \ ^ drivers/gpu/drm/nouveau/core/subdev/clock/gk20a.c:146:2: note: in expansion of macro 'do_div' do_div(rate, divider); ^ include/asm-generic/div64.h:35:17: note: expected 'uint64_t *' but argument is of type 'u32 *' extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor);
Signed-off-by: Thierry Reding treding@nvidia.com --- drivers/gpu/drm/nouveau/core/subdev/clock/gk20a.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/nouveau/core/subdev/clock/gk20a.c b/drivers/gpu/drm/nouveau/core/subdev/clock/gk20a.c index 425a8d5e9129..c571437afbd2 100644 --- a/drivers/gpu/drm/nouveau/core/subdev/clock/gk20a.c +++ b/drivers/gpu/drm/nouveau/core/subdev/clock/gk20a.c @@ -138,7 +138,7 @@ gk20a_pllg_read_mnp(struct gk20a_clock_priv *priv) static u32 gk20a_pllg_calc_rate(struct gk20a_clock_priv *priv) { - u32 rate; + u64 rate; u32 divider;
rate = priv->parent_rate * priv->n;