gpu: host1x: Enable Tegra186 syncpoint protection

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>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

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_to_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_to_channel(
+	struct host1x *host, struct host1x_syncpt *sp,
+	struct host1x_channel *ch)
+{
+	return host->syncpt_op->assign_to_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 *))
 {

drivers/gpu/host1x/hw/channel_hw.c

@@ -147,6 +147,8 @@ static int channel_submit(struct host1x_job *job)
 
 	syncval = host1x_syncpt_incr_max(sp, user_syncpt_incrs);
 
+	host1x_hw_syncpt_assign_to_channel(host, sp, ch);
+
 	job->syncpt_end = syncval;
 
 	/* add a setclass for modules that require it */

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_to_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_to_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_to_channel = syncpt_assign_to_channel,
+	.enable_protection = syncpt_enable_protection,
 };

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_to_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);