NVIDIA: SAUCE: memory: tegra: Skip SID override on HV

BugLink: https://bugs.launchpad.net/bugs/2072591

HV has blocked access to MC registers.
SID override programming is required on L4T.
Add a function to check if HV is present and skip SID override
programming in that case.

http://nvbugs/4062998

Signed-off-by: Ashish Mhetre <amhetre@nvidia.com>
Reviewed-by: Prathamesh Shete <pshete@nvidia.com>
Tested-by: Prathamesh Shete <pshete@nvidia.com>
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Acked-by: Jacob Martin <jacob.martin@canonical.com>
Acked-by: Noah Wager <noah.wager@canonical.com>
Signed-off-by: Noah Wager <noah.wager@canonical.com>

drivers/memory/tegra/tegra186.c

@@ -12,6 +12,7 @@
 #include <linux/platform_device.h>
 
 #include <soc/tegra/mc.h>
+#include <soc/tegra/tegra-platform-helper.h>
 
 #if defined(CONFIG_ARCH_TEGRA_186_SOC)
 #include <dt-bindings/memory/tegra186-mc.h>
@@ -121,6 +122,11 @@ static int tegra186_mc_probe_device(struct tegra_mc *mc, struct device *dev)
 	if (!tegra_dev_iommu_get_stream_id(dev, &sid))
 		return 0;
 
+	if (tegra_is_hypervisor_mode() == true) {
+		pr_debug("MC register access not allowed in Guest Linux\n");
+		return 0;
+	}
+
 	while (!of_parse_phandle_with_args(dev->of_node, "interconnects", "#interconnect-cells",
 					   index, &args)) {
 		if (args.np == mc->dev->of_node && args.args_count != 0) {

drivers/soc/tegra/Kconfig

@@ -170,3 +170,10 @@ config SOC_TEGRA_CBB
 	  Support for handling error from Tegra Control Backbone(CBB).
 	  This driver handles the errors from CBB and prints debug
 	  information about the failed transactions.
+
+config SOC_TEGRA_PLATFORM_HELPER
+	def_bool y
+	help
+	  This config enables support of the platform helpers APIs which can
+	  be used by the out-tree. If this config is y then the helper APIs
+	  are available else not.

include/soc/tegra/tegra-platform-helper.h

@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2023, NVIDIA CORPORATION.  All rights reserved.
+ */
+
+#ifndef TEGRA_PLATFORM_HELPER_H
+#define TEGRA_PLATFORM_HELPER_H
+
+static inline bool tegra_is_hypervisor_mode(void)
+{
+#ifdef CONFIG_OF
+	return of_property_read_bool(of_chosen,
+		"nvidia,tegra-hypervisor-mode");
+#else
+	return false;
+#endif
+}
+
+#endif /* TEGRA_PLATFORM_HELPER_H */