2015-02-06 09:21:05

by Geert Uytterhoeven

[permalink] [raw]
Subject: [PATCH v2] drm/nouveau/clk: Change rate from u32 to u64 in gk20a_pllg_calc_rate()

On 32-bit platforms using asm-generic/div64.h:

drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c: In function 'gk20a_pllg_calc_rate':
drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c:147:79: warning: comparison of distinct pointer types lacks a cast
do_div(rate, divider);
^
drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c:147:2: warning: right shift count >= width of type
do_div(rate, divider);
^
drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c:147:238: warning: passing argument 1 of '__div64_32' from incompatible pointer type
do_div(rate, divider);
^
In file included from arch/parisc/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/include/nvif/os.h:5,
from drivers/gpu/drm/nouveau/include/nvkm/core/os.h:3,
from drivers/gpu/drm/nouveau/include/nvkm/core/object.h:3,
from drivers/gpu/drm/nouveau/include/nvkm/core/subdev.h:3,
from drivers/gpu/drm/nouveau/include/nvkm/subdev/clk.h:3,
from drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c:25:
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);
^

do_div() is meant for 64-bit by 32-bit division, but both the dividend
and divisor are 32-bit here, causing the warning.

As the product of priv->parent_rate and priv->n may no longer fit in u32
soon, change rate from u32 to u64, which also fixes the warning.

Signed-off-by: Geert Uytterhoeven <[email protected]>
---
Compile-tested only.

This is v2 of "drm/nouveau/clk: Use plain "/" for 32-bit division".

v2:
- Change rate from u32 to u64 instead of changing the division.

parisc/allmodconfig:
http://kisskb.ellerman.id.au/kisskb/buildresult/12358386/
---
drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c b/drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c
index 65c532742b08d1c6..e87a964b8bea4d30 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c
@@ -139,7 +139,7 @@ gk20a_pllg_read_mnp(struct gk20a_clk_priv *priv)
static u32
gk20a_pllg_calc_rate(struct gk20a_clk_priv *priv)
{
- u32 rate;
+ u64 rate;
u32 divider;

rate = priv->parent_rate * priv->n;
--
1.9.1


2015-02-06 09:25:07

by Alexandre Courbot

[permalink] [raw]
Subject: Re: [PATCH v2] drm/nouveau/clk: Change rate from u32 to u64 in gk20a_pllg_calc_rate()

On 02/06/2015 06:20 PM, Geert Uytterhoeven wrote:
> On 32-bit platforms using asm-generic/div64.h:
>
> drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c: In function 'gk20a_pllg_calc_rate':
> drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c:147:79: warning: comparison of distinct pointer types lacks a cast
> do_div(rate, divider);
> ^
> drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c:147:2: warning: right shift count >= width of type
> do_div(rate, divider);
> ^
> drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c:147:238: warning: passing argument 1 of '__div64_32' from incompatible pointer type
> do_div(rate, divider);
> ^
> In file included from arch/parisc/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/include/nvif/os.h:5,
> from drivers/gpu/drm/nouveau/include/nvkm/core/os.h:3,
> from drivers/gpu/drm/nouveau/include/nvkm/core/object.h:3,
> from drivers/gpu/drm/nouveau/include/nvkm/core/subdev.h:3,
> from drivers/gpu/drm/nouveau/include/nvkm/subdev/clk.h:3,
> from drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c:25:
> 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);
> ^
>
> do_div() is meant for 64-bit by 32-bit division, but both the dividend
> and divisor are 32-bit here, causing the warning.
>
> As the product of priv->parent_rate and priv->n may no longer fit in u32
> soon, change rate from u32 to u64, which also fixes the warning.
>
> Signed-off-by: Geert Uytterhoeven <[email protected]>
> ---
> Compile-tested only.
>
> This is v2 of "drm/nouveau/clk: Use plain "/" for 32-bit division".
>
> v2:
> - Change rate from u32 to u64 instead of changing the division.
>
> parisc/allmodconfig:
> http://kisskb.ellerman.id.au/kisskb/buildresult/12358386/
> ---
> drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c b/drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c
> index 65c532742b08d1c6..e87a964b8bea4d30 100644
> --- a/drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c
> +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c
> @@ -139,7 +139,7 @@ gk20a_pllg_read_mnp(struct gk20a_clk_priv *priv)
> static u32
> gk20a_pllg_calc_rate(struct gk20a_clk_priv *priv)
> {
> - u32 rate;
> + u64 rate;
> u32 divider;
>
> rate = priv->parent_rate * priv->n;
>

Tested-by: Alexandre Courbot <[email protected]>

Adding Ben as he might want to take this in his tree?