1 files changed, 156 insertions, 0 deletions
diff --git a/drivers/gpu/drm/nouveau/nvif/chan.c b/drivers/gpu/drm/nouveau/nvif/chan.c
new file mode 100644
index 000000000000..baa10227d51a
--- /dev/null
+++ b/drivers/gpu/drm/nouveau/nvif/chan.c
@@ -0,0 +1,156 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (c) 2025, NVIDIA CORPORATION. All rights reserved.
+ */
+#include <nvif/chan.h>
+
+static void
+nvif_chan_gpfifo_push_kick(struct nvif_push *push)
+{
+	struct nvif_chan *chan = container_of(push, typeof(*chan), push);
+	u32 put = push->bgn - (u32 *)chan->push.mem.object.map.ptr;
+	u32 cnt;
+
+	if (chan->func->gpfifo.post) {
+		if (push->end - push->cur < chan->func->gpfifo.post_size)
+			push->end = push->cur + chan->func->gpfifo.post_size;
+
+		WARN_ON(nvif_chan_gpfifo_post(chan));
+	}
+
+	cnt = push->cur - push->bgn;
+
+	chan->func->gpfifo.push(chan, true, chan->push.addr + (put << 2), cnt << 2, false);
+	chan->func->gpfifo.kick(chan);
+}
+
+static int
+nvif_chan_gpfifo_push_wait(struct nvif_push *push, u32 push_nr)
+{
+	struct nvif_chan *chan = container_of(push, typeof(*chan), push);
+
+	return nvif_chan_gpfifo_wait(chan, 1, push_nr);
+}
+
+int
+nvif_chan_gpfifo_post(struct nvif_chan *chan)
+{
+	const u32 *map = chan->push.mem.object.map.ptr;
+	const u32 pbptr = (chan->push.cur - map) + chan->func->gpfifo.post_size;
+	const u32 gpptr = (chan->gpfifo.cur + 1) & chan->gpfifo.max;
+
+	return chan->func->gpfifo.post(chan, gpptr, pbptr);
+}
+
+void
+nvif_chan_gpfifo_push(struct nvif_chan *chan, u64 addr, u32 size, bool no_prefetch)
+{
+	chan->func->gpfifo.push(chan, false, addr, size, no_prefetch);
+}
+
+int
+nvif_chan_gpfifo_wait(struct nvif_chan *chan, u32 gpfifo_nr, u32 push_nr)
+{
+	struct nvif_push *push = &chan->push;
+	int ret = 0, time = 1000000;
+
+	if (gpfifo_nr) {
+		/* Account for pushbuf space needed by nvif_chan_gpfifo_post(),
+		 * if used after pushing userspace GPFIFO entries.
+		 */
+		if (chan->func->gpfifo.post)
+			push_nr += chan->func->gpfifo.post_size;
+	}
+
+	/* Account for the GPFIFO entry needed to submit pushbuf. */
+	if (push_nr)
+		gpfifo_nr++;
+
+	/* Wait for space in main push buffer. */
+	if (push->cur + push_nr > push->end) {
+		ret = nvif_chan_dma_wait(chan, push_nr);
+		if (ret)
+			return ret;
+	}
+
+	/* Wait for GPFIFO space. */
+	while (chan->gpfifo.free < gpfifo_nr) {
+		chan->gpfifo.free = chan->func->gpfifo.read_get(chan) - chan->gpfifo.cur - 1;
+		if (chan->gpfifo.free < 0)
+			chan->gpfifo.free += chan->gpfifo.max + 1;
+
+		if (chan->gpfifo.free < gpfifo_nr) {
+			if (!time--)
+				return -ETIMEDOUT;
+			udelay(1);
+		}
+	}
+
+	return 0;
+}
+
+void
+nvif_chan_gpfifo_ctor(const struct nvif_chan_func *func, void *userd, void *gpfifo, u32 gpfifo_size,
+		      void *push, u64 push_addr, u32 push_size, struct nvif_chan *chan)
+{
+	chan->func = func;
+
+	chan->userd.map.ptr = userd;
+
+	chan->gpfifo.map.ptr = gpfifo;
+	chan->gpfifo.max = (gpfifo_size >> 3) - 1;
+	chan->gpfifo.free = chan->gpfifo.max;
+
+	chan->push.mem.object.map.ptr = push;
+	chan->push.wait = nvif_chan_gpfifo_push_wait;
+	chan->push.kick = nvif_chan_gpfifo_push_kick;
+	chan->push.addr = push_addr;
+	chan->push.hw.max = push_size >> 2;
+	chan->push.bgn = chan->push.cur = chan->push.end = push;
+}
+
+int
+nvif_chan_dma_wait(struct nvif_chan *chan, u32 nr)
+{
+	struct nvif_push *push = &chan->push;
+	u32 cur = push->cur - (u32 *)push->mem.object.map.ptr;
+	u32 free, time = 1000000;
+
+	nr += chan->func->gpfifo.post_size;
+
+	do {
+		u32 get = chan->func->push.read_get(chan);
+
+		if (get <= cur) {
+			free = push->hw.max - cur;
+			if (free >= nr)
+				break;
+
+			PUSH_KICK(push);
+
+			while (get == 0) {
+				get = chan->func->push.read_get(chan);
+				if (get == 0) {
+					if (!time--)
+						return -ETIMEDOUT;
+					udelay(1);
+				}
+			}
+
+			cur = 0;
+		}
+
+		free = get - cur - 1;
+
+		if (free < nr) {
+			if (!time--)
+				return -ETIMEDOUT;
+			udelay(1);
+		}
+	} while (free < nr);
+
+	push->bgn = (u32 *)push->mem.object.map.ptr + cur;
+	push->cur = push->bgn;
+	push->end = push->bgn + free - chan->func->gpfifo.post_size;
+	return 0;
+}