[U-Boot] [PATCH] ARM: tegra: avoid more operations in non-secure world

[Stephen Warren]

From: Stephen Warren <swarren at nvidia.com>

A secure monitor that runs before U-Boot, and hence causes U-Boot to run
in non-secure world, must implement a few operations that U-Boot
otherwise implements when running in secure world. Fix U-Boot to skip
these operations when running in non-secure world. In particular:

- The secure monitor must provide the LP0 resume code and own LP0
  configuration in order to maintain security, so must initialize all
  the PMC scratch registers used by the boot ROM during LP0 resume.
  Consequently, U-Boot should not attempt to clear those registers,
  since the register accesses will fail or cause an error.

- The secure monitor owns system security, and so is responsible for
  configuring security-related items such as the VPR.

Signed-off-by: Stephen Warren <swarren at nvidia.com>
---
 arch/arm/mach-tegra/ap.c  |  9 +++++++--
 arch/arm/mach-tegra/gpu.c | 18 ++++++++++++------
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/arch/arm/mach-tegra/ap.c b/arch/arm/mach-tegra/ap.c
index bf8001d9db09..84c20a48ad4d 100644
--- a/arch/arm/mach-tegra/ap.c
+++ b/arch/arm/mach-tegra/ap.c
@@ -155,8 +155,13 @@ static void init_pmc_scratch(void)
 	int i;
 
 	/* SCRATCH0 is initialized by the boot ROM and shouldn't be cleared */
-	for (i = 0; i < 23; i++)
-		writel(0, &pmc->pmc_scratch1+i);
+#if defined(CONFIG_TEGRA_SUPPORT_NON_SECURE)
+	if (!tegra_cpu_is_non_secure())
+#endif
+	{
+		for (i = 0; i < 23; i++)
+			writel(0, &pmc->pmc_scratch1 + i);
+	}
 
 	/* ODMDATA is for kernel use to determine RAM size, LP config, etc. */
 	odmdata = get_odmdata();
diff --git a/arch/arm/mach-tegra/gpu.c b/arch/arm/mach-tegra/gpu.c
index 2e203f735bf3..e047f678211d 100644
--- a/arch/arm/mach-tegra/gpu.c
+++ b/arch/arm/mach-tegra/gpu.c
@@ -9,6 +9,7 @@
 #include <asm/io.h>
 #include <asm/arch/tegra.h>
 #include <asm/arch/mc.h>
+#include <asm/arch-tegra/ap.h>
 
 #include <fdt_support.h>
 
@@ -18,12 +19,17 @@ void tegra_gpu_config(void)
 {
 	struct mc_ctlr *mc = (struct mc_ctlr *)NV_PA_MC_BASE;
 
-	/* Turn VPR off */
-	writel(0, &mc->mc_video_protect_size_mb);
-	writel(TEGRA_MC_VIDEO_PROTECT_REG_WRITE_ACCESS_DISABLED,
-	       &mc->mc_video_protect_reg_ctrl);
-	/* read back to ensure the write went through */
-	readl(&mc->mc_video_protect_reg_ctrl);
+#if defined(CONFIG_TEGRA_SUPPORT_NON_SECURE)
+	if (!tegra_cpu_is_non_secure())
+#endif
+	{
+		/* Turn VPR off */
+		writel(0, &mc->mc_video_protect_size_mb);
+		writel(TEGRA_MC_VIDEO_PROTECT_REG_WRITE_ACCESS_DISABLED,
+		       &mc->mc_video_protect_reg_ctrl);
+		/* read back to ensure the write went through */
+		readl(&mc->mc_video_protect_reg_ctrl);
+	}
 
 	debug("configured VPR\n");
 
-- 
2.18.0