nvhost: Throttle low-priority tasks

Add interface for setting priority of a channel. When the priority is
low, wait for channel to become empty before submitting it.

Bug 864407

Signed-off-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-on: http://git-master/r/57237
(cherry picked from commit 75228616ee2c3073e391c529aecb3f82be3fc5a4)
Change-Id: Ife8057586bfc3be02f772034bd2c497b2c59f7aa
Reviewed-on: http://git-master/r/60391
Reviewed-by: Yu-Huan Hsu <yhsu@nvidia.com>

4 files changed, 57 insertions, 5 deletions

diff --git a/drivers/video/tegra/host/dev.c b/drivers/video/tegra/host/dev.c
index 406ca7c1814a..3d0875dcb37e 100644
--- a/drivers/video/tegra/host/dev.c
+++ b/drivers/video/tegra/host/dev.c
@@ -66,6 +66,7 @@ struct nvhost_channel_userctx {
 	struct nvhost_waitchk waitchks[NVHOST_MAX_WAIT_CHECKS];
 	struct nvhost_waitchk *cur_waitchk;
 	struct nvhost_userctx_timeout timeout;
+	u32 priority;
 };
 
 struct nvhost_ctrl_userctx {
@@ -130,6 +131,7 @@ static int nvhost_channelopen(struct inode *inode, struct file *filp)
 			goto fail;
 		priv->hwctx->timeout = &priv->timeout;
 	}
+	priv->priority = NVHOST_PRIORITY_MEDIUM;
 
 	priv->gathers = nvmap_mmap(priv->gather_mem);
 	if (!priv->gathers)
@@ -324,14 +326,14 @@ static int nvhost_ioctl_channel_flush(
 	ctx->timeout.syncpt_id = ctx->hdr.syncpt_id;
 
 	/* context switch if needed, and submit user's gathers to the channel */
-	BUG_ON(!channel_op(ctx->ch).submit);
-	err = channel_op(ctx->ch).submit(ctx->ch, ctx->hwctx, ctx->nvmap,
+	err = nvhost_channel_submit(ctx->ch, ctx->hwctx, ctx->nvmap,
 				ctx->gathers, ctx->cur_gather,
 				ctx->waitchks, ctx->cur_waitchk,
 				ctx->hdr.waitchk_mask,
 				ctx->unpinarray, num_unpin,
 				ctx->hdr.syncpt_id, ctx->hdr.syncpt_incrs,
 				&ctx->timeout,
+				ctx->priority,
 				&args->value,
 				null_kickoff);
 	if (err)
@@ -473,6 +475,10 @@ static long nvhost_channelctl(struct file *filp,
 		((struct nvhost_get_param_args *)buf)->value =
 				priv->timeout.has_timedout;
 		break;
+	case NVHOST_IOCTL_CHANNEL_SET_PRIORITY:
+		priv->timeout.timeout =
+			(u32)((struct nvhost_set_priority_args *)buf)->priority;
+		break;
 	default:
 		err = -ENOTTY;
 		break;
diff --git a/drivers/video/tegra/host/nvhost_channel.c b/drivers/video/tegra/host/nvhost_channel.c
index 48f018cca4b2..64bc59ed4b9c 100644
--- a/drivers/video/tegra/host/nvhost_channel.c
+++ b/drivers/video/tegra/host/nvhost_channel.c
@@ -24,9 +24,46 @@
 #include "dev.h"
 #include "nvhost_hwctx.h"
 #include <trace/events/nvhost.h>
+#include <linux/nvhost_ioctl.h>
 
 #include <linux/platform_device.h>
 
+int nvhost_channel_submit(
+	struct nvhost_channel *channel,
+	struct nvhost_hwctx *hwctx,
+	struct nvmap_client *user_nvmap,
+	u32 *gather,
+	u32 *gather_end,
+	struct nvhost_waitchk *waitchk,
+	struct nvhost_waitchk *waitchk_end,
+	u32 waitchk_mask,
+	struct nvmap_handle **unpins,
+	int nr_unpins,
+	u32 syncpt_id,
+	u32 syncpt_incrs,
+	struct nvhost_userctx_timeout *timeout_ctx,
+	u32 priority,
+	u32 *syncpt_value,
+	bool null_kickoff)
+{
+	BUG_ON(!channel_op(channel).submit);
+
+	/* Low priority submits wait until sync queue is empty */
+	if (priority < NVHOST_PRIORITY_MEDIUM)
+		nvhost_cdma_wait(&channel->cdma, CDMA_EVENT_SYNC_QUEUE_EMPTY);
+
+	return channel_op(channel).submit(channel,
+			hwctx,
+			user_nvmap,
+			gather, gather_end,
+			waitchk, waitchk_end, waitchk_mask,
+			unpins, nr_unpins,
+			syncpt_id, syncpt_incrs,
+			timeout_ctx,
+			syncpt_value,
+			null_kickoff);
+}
+
 struct nvhost_channel *nvhost_getchannel(struct nvhost_channel *ch)
 {
 	int err = 0;
diff --git a/drivers/video/tegra/host/nvhost_channel.h b/drivers/video/tegra/host/nvhost_channel.h
index e4dc4e2d79e8..18e27a177f66 100644
--- a/drivers/video/tegra/host/nvhost_channel.h
+++ b/drivers/video/tegra/host/nvhost_channel.h
@@ -93,8 +93,8 @@ int nvhost_channel_submit(
 	int nr_unpins,
 	u32 syncpt_id,
 	u32 syncpt_incrs,
-	u32 timeout,
-	void *timeout_ctx,
+	struct nvhost_userctx_timeout *timeout_ctx,
+	u32 priority,
 	u32 *syncpt_value,
 	bool null_kickoff);
 
diff --git a/include/linux/nvhost_ioctl.h b/include/linux/nvhost_ioctl.h
index ef6685ea418f..31ff22f45fb9 100644
--- a/include/linux/nvhost_ioctl.h
+++ b/include/linux/nvhost_ioctl.h
@@ -34,6 +34,9 @@
 #define NVHOST_NO_TIMEOUT (-1)
 #define NVHOST_NO_CONTEXT 0x0
 #define NVHOST_IOCTL_MAGIC 'H'
+#define NVHOST_PRIORITY_LOW 50
+#define NVHOST_PRIORITY_MEDIUM 100
+#define NVHOST_PRIORITY_HIGH 150
 
 /* version 0 header (used with write() submit interface) */
 struct nvhost_submit_hdr {
@@ -100,6 +103,10 @@ struct nvhost_set_timeout_args {
 	__u32 timeout;
 };
 
+struct nvhost_set_priority_args {
+	__u32 priority;
+};
+
 #define NVHOST_IOCTL_CHANNEL_FLUSH		\
 	_IOR(NVHOST_IOCTL_MAGIC, 1, struct nvhost_get_param_args)
 #define NVHOST_IOCTL_CHANNEL_GET_SYNCPOINTS	\
@@ -124,8 +131,10 @@ struct nvhost_set_timeout_args {
 	_IOW(NVHOST_IOCTL_MAGIC, 11, struct nvhost_set_timeout_args)
 #define NVHOST_IOCTL_CHANNEL_GET_TIMEDOUT	\
 	_IOR(NVHOST_IOCTL_MAGIC, 12, struct nvhost_get_param_args)
+#define NVHOST_IOCTL_CHANNEL_SET_PRIORITY	\
+	_IOW(NVHOST_IOCTL_MAGIC, 13, struct nvhost_set_priority_args)
 #define NVHOST_IOCTL_CHANNEL_LAST		\
-	_IOC_NR(NVHOST_IOCTL_CHANNEL_GET_TIMEDOUT)
+	_IOC_NR(NVHOST_IOCTL_CHANNEL_SET_PRIORITY)
 #define NVHOST_IOCTL_CHANNEL_MAX_ARG_SIZE sizeof(struct nvhost_submit_hdr_ext)
 
 struct nvhost_ctrl_syncpt_read_args {