[PATCH v2 1/6] gpu: host1x: Enable Tegra186 syncpoint protection

[Mikko Perttunen <mperttunen@nvidia.com>]

Since Tegra186 the Host1x hardware allows syncpoints to be assigned to
specific channels, preventing any other channels from incrementing
them.

Enable this feature where available and assign syncpoints to channels
when submitting a job. Syncpoints are currently never unassigned from
channels since that would require extra work and is unnecessary with
the current channel allocation model.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
---

Notes:
    v2:
    - Changed from set_protection(bool) to enable_protection
    - Added some comments
    - Added missing check for hv_regs being NULL in
      enable_protection

 drivers/gpu/host1x/dev.h           | 15 +++++++++++++
 drivers/gpu/host1x/hw/channel_hw.c |  3 +++
 drivers/gpu/host1x/hw/syncpt_hw.c  | 46 ++++++++++++++++++++++++++++++++++++++
 drivers/gpu/host1x/syncpt.c        |  8 +++++++
 4 files changed, 72 insertions(+)

diff --git a/drivers/gpu/host1x/dev.h b/drivers/gpu/host1x/dev.h
index def802c0a6bf..7497cc5ead9e 100644
--- a/drivers/gpu/host1x/dev.h
+++ b/drivers/gpu/host1x/dev.h
@@ -79,6 +79,9 @@ struct host1x_syncpt_ops {
 	u32 (*load)(struct host1x_syncpt *syncpt);
 	int (*cpu_incr)(struct host1x_syncpt *syncpt);
 	int (*patch_wait)(struct host1x_syncpt *syncpt, void *patch_addr);
+	void (*assign_channel)(struct host1x_syncpt *syncpt,
+	                       struct host1x_channel *channel);
+	void (*enable_protection)(struct host1x *host);
 };
 
 struct host1x_intr_ops {
@@ -186,6 +189,18 @@ static inline int host1x_hw_syncpt_patch_wait(struct host1x *host,
 	return host->syncpt_op->patch_wait(sp, patch_addr);
 }
 
+static inline void host1x_hw_syncpt_assign_channel(struct host1x *host,
+						   struct host1x_syncpt *sp,
+						   struct host1x_channel *ch)
+{
+	return host->syncpt_op->assign_channel(sp, ch);
+}
+
+static inline void host1x_hw_syncpt_enable_protection(struct host1x *host)
+{
+	return host->syncpt_op->enable_protection(host);
+}
+
 static inline int host1x_hw_intr_init_host_sync(struct host1x *host, u32 cpm,
 			void (*syncpt_thresh_work)(struct work_struct *))
 {
diff --git a/drivers/gpu/host1x/hw/channel_hw.c b/drivers/gpu/host1x/hw/channel_hw.c
index 8447a56c41ca..0161da331702 100644
--- a/drivers/gpu/host1x/hw/channel_hw.c
+++ b/drivers/gpu/host1x/hw/channel_hw.c
@@ -147,6 +147,9 @@ static int channel_submit(struct host1x_job *job)
 
 	syncval = host1x_syncpt_incr_max(sp, user_syncpt_incrs);
 
+	/* assign syncpoint to channel */
+	host1x_hw_syncpt_assign_channel(host, sp, ch);
+
 	job->syncpt_end = syncval;
 
 	/* add a setclass for modules that require it */
diff --git a/drivers/gpu/host1x/hw/syncpt_hw.c b/drivers/gpu/host1x/hw/syncpt_hw.c
index 7b0270d60742..dc7a44614fef 100644
--- a/drivers/gpu/host1x/hw/syncpt_hw.c
+++ b/drivers/gpu/host1x/hw/syncpt_hw.c
@@ -106,6 +106,50 @@ static int syncpt_patch_wait(struct host1x_syncpt *sp, void *patch_addr)
 	return 0;
 }
 
+/**
+ * syncpt_assign_channel() - Assign syncpoint to channel
+ * @sp: syncpoint
+ * @ch: channel
+ *
+ * On chips with the syncpoint protection feature (Tegra186+), assign @sp to
+ * @ch, preventing other channels from incrementing the syncpoints. If @ch is
+ * NULL, unassigns the syncpoint.
+ *
+ * On older chips, do nothing.
+ */
+static void syncpt_assign_channel(struct host1x_syncpt *sp,
+				  struct host1x_channel *ch)
+{
+#if HOST1X_HW >= 6
+	struct host1x *host = sp->host;
+
+	if (!host->hv_regs)
+		return;
+
+	host1x_sync_writel(host,
+			   HOST1X_SYNC_SYNCPT_CH_APP_CH(ch ? ch->id : 0xff),
+			   HOST1X_SYNC_SYNCPT_CH_APP(sp->id));
+#endif
+}
+
+/**
+ * syncpt_enable_protection() - Enable syncpoint protection
+ * @host: host1x instance
+ *
+ * On chips with the syncpoint protection feature (Tegra186+), enable this
+ * feature. On older chips, do nothing.
+ */
+static void syncpt_enable_protection(struct host1x *host)
+{
+#if HOST1X_HW >= 6
+	if (!host->hv_regs)
+		return;
+
+	host1x_hypervisor_writel(host, HOST1X_HV_SYNCPT_PROT_EN_CH_EN,
+				 HOST1X_HV_SYNCPT_PROT_EN);
+#endif
+}
+
 static const struct host1x_syncpt_ops host1x_syncpt_ops = {
 	.restore = syncpt_restore,
 	.restore_wait_base = syncpt_restore_wait_base,
@@ -113,4 +157,6 @@ static const struct host1x_syncpt_ops host1x_syncpt_ops = {
 	.load = syncpt_load,
 	.cpu_incr = syncpt_cpu_incr,
 	.patch_wait = syncpt_patch_wait,
+	.assign_channel = syncpt_assign_channel,
+	.enable_protection = syncpt_enable_protection,
 };
diff --git a/drivers/gpu/host1x/syncpt.c b/drivers/gpu/host1x/syncpt.c
index 048ac9e344ce..4c7a4c8b2ad2 100644
--- a/drivers/gpu/host1x/syncpt.c
+++ b/drivers/gpu/host1x/syncpt.c
@@ -398,6 +398,13 @@ int host1x_syncpt_init(struct host1x *host)
 	for (i = 0; i < host->info->nb_pts; i++) {
 		syncpt[i].id = i;
 		syncpt[i].host = host;
+
+		/*
+		 * Unassign syncpt from channels for purposes of Tegra186
+		 * syncpoint protection. This prevents any channel from
+		 * accessing it until it is reassigned.
+		 */
+		host1x_hw_syncpt_assign_channel(host, &syncpt[i], NULL);
 	}
 
 	for (i = 0; i < host->info->nb_bases; i++)
@@ -408,6 +415,7 @@ int host1x_syncpt_init(struct host1x *host)
 	host->bases = bases;
 
 	host1x_syncpt_restore(host);
+	host1x_hw_syncpt_enable_protection(host);
 
 	/* Allocate sync point to use for clearing waits for expired fences */
 	host->nop_sp = host1x_syncpt_alloc(host, NULL, 0);
-- 
2.14.1