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authorStephen Warren <swarren@nvidia.com>2015-01-19 16:25:52 -0700
committerTom Warren <twarren@nvidia.com>2015-03-04 10:08:57 -0700
commit73c38934daa10b518b20f2d21298fc8a8226843b (patch)
tree68d0f8837373d2fce809f7e38bb4ff89f14558b9 /board
parent026baff755cbab0c8bfc12d78e6966718f5325a5 (diff)
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ARM: tegra: support running in non-secure mode
When the CPU is in non-secure (NS) mode (when running U-Boot under a secure monitor), certain actions cannot be taken, since they would need to write to secure-only registers. One example is configuring the ARM architectural timer's CNTFRQ register. We could support this in one of two ways: 1) Compile twice, once for secure mode (in which case anything goes) and once for non-secure mode (in which case certain actions are disabled). This complicates things, since everyone needs to keep track of different U-Boot binaries for different situations. 2) Detect NS mode at run-time, and optionally skip any impossible actions. This has the advantage of a single U-Boot binary working in all cases. (2) is not possible on ARM in general, since there's no architectural way to detect secure-vs-non-secure. However, there is a Tegra-specific way to detect this. This patches uses that feature to detect secure vs. NS mode on Tegra, and uses that to: * Skip the ARM arch timer initialization. * Set/clear an environment variable so that boot scripts can take different action depending on which mode the CPU is in. This might be something like: if CPU is secure: load secure monitor code into RAM. boot secure monitor. secure monitor will restart (a new copy of) U-Boot in NS mode. else: execute normal boot process Signed-off-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Tom Warren <twarren@nvidia.com>
Diffstat (limited to 'board')
-rw-r--r--board/nvidia/common/board.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/board/nvidia/common/board.c b/board/nvidia/common/board.c
index 80ef8fd..018dddb 100644
--- a/board/nvidia/common/board.c
+++ b/board/nvidia/common/board.c
@@ -21,6 +21,7 @@
#include <asm/arch/pwm.h>
#endif
#include <asm/arch/tegra.h>
+#include <asm/arch-tegra/ap.h>
#include <asm/arch-tegra/board.h>
#include <asm/arch-tegra/clk_rst.h>
#include <asm/arch-tegra/pmc.h>
@@ -180,6 +181,14 @@ int board_late_init(void)
/* Make sure we finish initing the LCD */
tegra_lcd_check_next_stage(gd->fdt_blob, 1);
#endif
+#if defined(CONFIG_TEGRA_SUPPORT_NON_SECURE)
+ if (tegra_cpu_is_non_secure()) {
+ printf("CPU is in NS mode\n");
+ setenv("cpu_ns_mode", "1");
+ } else {
+ setenv("cpu_ns_mode", "");
+ }
+#endif
return 0;
}