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From: Arnd Bergmann <arnd@arndb.de>
To: Jammy Zhou <Jammy.Zhou@amd.com>, David Airlie <airlied@linux.ie>
Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	"Alex Deucher" <alexander.deucher@amd.com>,
	"David Zhang" <david1.zhang@amd.com>,
	"Eric Huang" <JinHuiEric.Huang@amd.com>,
	"Christian König" <christian.koenig@amd.com>
Subject: [PATCH] drm: powerplay: use div64_s64 instead of do_div
Date: Fri, 01 Jan 2016 14:07:41 +0100	[thread overview]
Message-ID: <5249276.tkZ1gbxakA@wuerfel> (raw)

The newly added code for Fiji creates a correct compiler warning
about invalid use of the do_div macro:

In file included from powerplay/hwmgr/ppatomctrl.c:31:0:
drivers/gpu/drm/amd/amdgpu/../powerplay/hwmgr/ppevvmath.h: In function 'fDivide':
drivers/gpu/drm/amd/amdgpu/../powerplay/hwmgr/ppevvmath.h:382:89: warning: comparison of distinct pointer types lacks a cast
     do_div(longlongX, longlongY); /*Q(32,32) divided by Q(16,16) = Q(16,16) Back to original format */

do_div() divides an unsigned 64-bit number by an unsigned 32-bit number.
The code instead wants to divide two signed 64-bit numbers, which is done
using the div64_s64 function.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 770911a3cfbb ("drm/amd/powerplay: add/update headers for Fiji SMU and DPM")
---
Found on ARM allmodconfig on yesterday's linux-next 

diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/ppevvmath.h b/drivers/gpu/drm/amd/powerplay/hwmgr/ppevvmath.h
index 42f2423cddea..411cb0fcdf98 100644
--- a/drivers/gpu/drm/amd/powerplay/hwmgr/ppevvmath.h
+++ b/drivers/gpu/drm/amd/powerplay/hwmgr/ppevvmath.h
@@ -379,7 +379,7 @@ fInt fDivide (fInt X, fInt Y)
 
     longlongX = longlongX << 16; /*Q(16,16) -> Q(32,32) */
 
-    do_div(longlongX, longlongY); /*Q(32,32) divided by Q(16,16) = Q(16,16) Back to original format */
+    div64_s64(longlongX, longlongY); /*Q(32,32) divided by Q(16,16) = Q(16,16) Back to original format */
 
     fQuotient.full = (int)longlongX;
     return fQuotient;

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WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: Jammy Zhou <Jammy.Zhou@amd.com>, David Airlie <airlied@linux.ie>
Cc: "Eric Huang" <JinHuiEric.Huang@amd.com>,
	"Alex Deucher" <alexander.deucher@amd.com>,
	"Christian König" <christian.koenig@amd.com>,
	"David Zhang" <david1.zhang@amd.com>,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org
Subject: [PATCH] drm: powerplay: use div64_s64 instead of do_div
Date: Fri, 01 Jan 2016 14:07:41 +0100	[thread overview]
Message-ID: <5249276.tkZ1gbxakA@wuerfel> (raw)

The newly added code for Fiji creates a correct compiler warning
about invalid use of the do_div macro:

In file included from powerplay/hwmgr/ppatomctrl.c:31:0:
drivers/gpu/drm/amd/amdgpu/../powerplay/hwmgr/ppevvmath.h: In function 'fDivide':
drivers/gpu/drm/amd/amdgpu/../powerplay/hwmgr/ppevvmath.h:382:89: warning: comparison of distinct pointer types lacks a cast
     do_div(longlongX, longlongY); /*Q(32,32) divided by Q(16,16) = Q(16,16) Back to original format */

do_div() divides an unsigned 64-bit number by an unsigned 32-bit number.
The code instead wants to divide two signed 64-bit numbers, which is done
using the div64_s64 function.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 770911a3cfbb ("drm/amd/powerplay: add/update headers for Fiji SMU and DPM")
---
Found on ARM allmodconfig on yesterday's linux-next 

diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/ppevvmath.h b/drivers/gpu/drm/amd/powerplay/hwmgr/ppevvmath.h
index 42f2423cddea..411cb0fcdf98 100644
--- a/drivers/gpu/drm/amd/powerplay/hwmgr/ppevvmath.h
+++ b/drivers/gpu/drm/amd/powerplay/hwmgr/ppevvmath.h
@@ -379,7 +379,7 @@ fInt fDivide (fInt X, fInt Y)
 
     longlongX = longlongX << 16; /*Q(16,16) -> Q(32,32) */
 
-    do_div(longlongX, longlongY); /*Q(32,32) divided by Q(16,16) = Q(16,16) Back to original format */
+    div64_s64(longlongX, longlongY); /*Q(32,32) divided by Q(16,16) = Q(16,16) Back to original format */
 
     fQuotient.full = (int)longlongX;
     return fQuotient;


             reply	other threads:[~2016-01-01 13:07 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-01 13:07 Arnd Bergmann [this message]
2016-01-01 13:07 ` [PATCH] drm: powerplay: use div64_s64 instead of do_div Arnd Bergmann
2016-01-04  8:17 ` Thierry Reding
2016-01-04  8:17   ` Thierry Reding
2016-01-04 12:48 ` Christian König
2016-01-04 12:48   ` Christian König
2016-01-04 15:42 ` Alex Deucher
2016-01-04 15:42   ` Alex Deucher

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