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/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,
 };