Tegra: restrict non-secure PMC accesses

Platforms that do not support bpmp firmware, do not need access
to the PMC block from outside of the CPU complex. The agents
running on the CPU can always access the PMC through the EL3
exception space.

This patch restricts non-secure world access to the PMC block on
such platforms.

Change-Id: I2c4318dc07ddf6407c1700595e0f4aac377ba258
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
diff --git a/plat/nvidia/tegra/include/t210/tegra_def.h b/plat/nvidia/tegra/include/t210/tegra_def.h
index 7e3789c..bbcfdc5 100644
--- a/plat/nvidia/tegra/include/t210/tegra_def.h
+++ b/plat/nvidia/tegra/include/t210/tegra_def.h
@@ -175,6 +175,8 @@
  ******************************************************************************/
 #define TEGRA_MISC_BASE			U(0x70000000)
 #define  HARDWARE_REVISION_OFFSET	U(0x804)
+#define  APB_SLAVE_SECURITY_ENABLE	U(0xC00)
+#define  PMC_SECURITY_EN_BIT		(U(1) << 13)
 #define  PINMUX_AUX_DVFS_PWM		U(0x3184)
 #define  PINMUX_PWM_TRISTATE		(U(1) << 4)
 
diff --git a/plat/nvidia/tegra/soc/t210/plat_psci_handlers.c b/plat/nvidia/tegra/soc/t210/plat_psci_handlers.c
index 7e176e6..b7d10af 100644
--- a/plat/nvidia/tegra/soc/t210/plat_psci_handlers.c
+++ b/plat/nvidia/tegra/soc/t210/plat_psci_handlers.c
@@ -473,6 +473,11 @@
 			offset = plat_params->tzdram_base - plat_params->sc7entry_fw_base;
 			tegra_memctrl_tzdram_setup(plat_params->sc7entry_fw_base,
 				plat_params->tzdram_size + offset);
+
+			/* restrict PMC access to secure world */
+			val = mmio_read_32(TEGRA_MISC_BASE + APB_SLAVE_SECURITY_ENABLE);
+			val |= PMC_SECURITY_EN_BIT;
+			mmio_write_32(TEGRA_MISC_BASE + APB_SLAVE_SECURITY_ENABLE, val);
 		}
 	}
 
diff --git a/plat/nvidia/tegra/soc/t210/plat_setup.c b/plat/nvidia/tegra/soc/t210/plat_setup.c
index d6b0853..9fb5169 100644
--- a/plat/nvidia/tegra/soc/t210/plat_setup.c
+++ b/plat/nvidia/tegra/soc/t210/plat_setup.c
@@ -157,6 +157,7 @@
 	const plat_params_from_bl2_t *plat_params = bl31_get_plat_params();
 	uint64_t sc7entry_end, offset;
 	int ret;
+	uint32_t val;
 
 	/* memmap TZDRAM area containing the SC7 Entry Firmware */
 	if (plat_params->sc7entry_fw_base && plat_params->sc7entry_fw_size) {
@@ -193,6 +194,11 @@
 				plat_params->sc7entry_fw_size,
 				MT_SECURE | MT_RO_DATA);
 		assert(ret == 0);
+
+		/* restrict PMC access to secure world */
+		val = mmio_read_32(TEGRA_MISC_BASE + APB_SLAVE_SECURITY_ENABLE);
+		val |= PMC_SECURITY_EN_BIT;
+		mmio_write_32(TEGRA_MISC_BASE + APB_SLAVE_SECURITY_ENABLE, val);
 	}
 }