drm/nouveau/nvif: protect waits against GPU falling off the bus

Signed-off-by: NBen Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/dispnv04/dac.c

@@ -35,7 +35,8 @@
 
 #include <subdev/bios/gpio.h>
 #include <subdev/gpio.h>
-#include <subdev/timer.h>
+
+#include <nvif/timer.h>
 
 int nv04_dac_output_offset(struct drm_encoder *encoder)
 {

drivers/gpu/drm/nouveau/dispnv04/hw.c

@@ -26,6 +26,7 @@
 #include "hw.h"
 
 #include <subdev/bios/pll.h>
+#include <nvif/timer.h>
 
 #define CHIPSET_NFORCE 0x01a0
 #define CHIPSET_NFORCE2 0x01f0

drivers/gpu/drm/nouveau/dispnv50/base507c.c

@@ -23,6 +23,7 @@
 
 #include <nvif/cl507c.h>
 #include <nvif/event.h>
+#include <nvif/timer.h>
 
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_fourcc.h>

drivers/gpu/drm/nouveau/dispnv50/core507d.c

@@ -23,6 +23,7 @@
 #include "head.h"
 
 #include <nvif/cl507d.h>
+#include <nvif/timer.h>
 
 #include "nouveau_bo.h"
 

drivers/gpu/drm/nouveau/dispnv50/corec37d.c

@@ -24,6 +24,8 @@
 
 #include <nouveau_bo.h>
 
+#include <nvif/timer.h>
+
 void
 corec37d_wndw_owner(struct nv50_core *core)
 {

drivers/gpu/drm/nouveau/dispnv50/disp.c

@@ -45,6 +45,7 @@
 #include <nvif/cl5070.h>
 #include <nvif/cl507d.h>
 #include <nvif/event.h>
+#include <nvif/timer.h>
 
 #include "nouveau_drv.h"
 #include "nouveau_dma.h"

drivers/gpu/drm/nouveau/dispnv50/ovly827e.c

@@ -24,6 +24,8 @@
 
 #include <nouveau_bo.h>
 
+#include <nvif/timer.h>
+
 static void
 ovly827e_image_set(struct nv50_wndw *wndw, struct nv50_wndw_atom *asyw)
 {

drivers/gpu/drm/nouveau/include/nvif/device.h

@@ -23,27 +23,6 @@ int  nvif_device_init(struct nvif_object *, u32 handle, s32 oclass, void *, u32,
 void nvif_device_fini(struct nvif_device *);
 u64  nvif_device_time(struct nvif_device *);
 
-/* Delay based on GPU time (ie. PTIMER).
- *
- * Will return -ETIMEDOUT unless the loop was terminated with 'break',
- * where it will return the number of nanoseconds taken instead.
- */
-#define nvif_nsec(d,n,cond...) ({                                              \
-	struct nvif_device *_device = (d);                                     \
-	u64 _nsecs = (n), _time0 = nvif_device_time(_device);                  \
-	s64 _taken = 0;                                                        \
-                                                                               \
-	do {                                                                   \
-		cond                                                           \
-	} while (_taken = nvif_device_time(_device) - _time0, _taken < _nsecs);\
-                                                                               \
-	if (_taken >= _nsecs)                                                  \
-		_taken = -ETIMEDOUT;                                           \
-	_taken;                                                                \
-})
-#define nvif_usec(d,u,cond...) nvif_nsec((d), (u) * 1000, ##cond)
-#define nvif_msec(d,m,cond...) nvif_usec((d), (m) * 1000, ##cond)
-
 /*XXX*/
 #include <subdev/bios.h>
 #include <subdev/fb.h>

drivers/gpu/drm/nouveau/include/nvif/timer.h

+#ifndef __NVIF_TIMER_H__
+#define __NVIF_TIMER_H__
+#include <nvif/os.h>
+
+struct nvif_timer_wait {
+	struct nvif_device *device;
+	u64 limit;
+	u64 time0;
+	u64 time1;
+	int reads;
+};
+
+void nvif_timer_wait_init(struct nvif_device *, u64 nsec,
+			  struct nvif_timer_wait *);
+s64 nvif_timer_wait_test(struct nvif_timer_wait *);
+
+/* Delay based on GPU time (ie. PTIMER).
+ *
+ * Will return -ETIMEDOUT unless the loop was terminated with 'break',
+ * where it will return the number of nanoseconds taken instead.
+ */
+#define nvif_nsec(d,n,cond...) ({                                              \
+	struct nvif_timer_wait _wait;                                          \
+	s64 _taken = 0;                                                        \
+                                                                               \
+	nvif_timer_wait_init((d), (n), &_wait);                                \
+	do {                                                                   \
+		cond                                                           \
+	} while ((_taken = nvif_timer_wait_test(&_wait)) >= 0);                \
+                                                                               \
+	_taken;                                                                \
+})
+#define nvif_usec(d,u,cond...) nvif_nsec((d), (u) * 1000, ##cond)
+#define nvif_msec(d,m,cond...) nvif_usec((d), (m) * 1000, ##cond)
+#endif

drivers/gpu/drm/nouveau/nvif/Kbuild

@@ -8,6 +8,7 @@ nvif-y += nvif/fifo.o
 nvif-y += nvif/mem.o
 nvif-y += nvif/mmu.o
 nvif-y += nvif/notify.o
+nvif-y += nvif/timer.o
 nvif-y += nvif/vmm.o
 
 # Usermode classes

drivers/gpu/drm/nouveau/nvif/timer.c

+/*
+ * Copyright 2020 Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+#include <nvif/timer.h>
+#include <nvif/device.h>
+
+s64
+nvif_timer_wait_test(struct nvif_timer_wait *wait)
+{
+	u64 time = nvif_device_time(wait->device);
+
+	if (wait->reads == 0) {
+		wait->time0 = time;
+		wait->time1 = time;
+	}
+
+	if (wait->time1 == time) {
+		if (WARN_ON(wait->reads++ == 16))
+			return -ETIMEDOUT;
+	} else {
+		wait->time1 = time;
+		wait->reads = 1;
+	}
+
+	if (wait->time1 - wait->time0 > wait->limit)
+		return -ETIMEDOUT;
+
+	return wait->time1 - wait->time0;
+}
+
+void
+nvif_timer_wait_init(struct nvif_device *device, u64 nsec,
+		     struct nvif_timer_wait *wait)
+{
+	wait->device = device;
+	wait->limit = nsec;
+	wait->reads = 0;
+}