tegra132: prepare cpu startup in psci

In order to start CPUs while in secmon/psci one needs to
set up the proper SoC state. Therefore, refactor the current
CPU startup API to allow for this by adding cpu_prepare_startup()
and start_cpu_silent().

BUG=chrome-os-partner:32136
BRANCH=None
TEST=Built and booted kernel.

Change-Id: I1424500f6c9398f7d44350949c25bb3d4832cec7
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 70f9cf67085b345b529b41dd6554e37d38a5b350
Original-Change-Id: I842a391d3e27ddbfcdef1a2d60e3c66e60f99c77
Original-Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/231936
Original-Reviewed-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: http://review.coreboot.org/9531
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/soc/nvidia/tegra132/Makefile.inc

@@ -94,6 +94,8 @@ ramstage-$(CONFIG_DRIVERS_UART) += uart.c
 ramstage-y += ../tegra/usb.c
 ramstage-$(CONFIG_ARCH_USE_SECURE_MONITOR) += secmon.c
 
+secmon-$(CONFIG_ARCH_USE_SECURE_MONITOR) += 32bit_reset.S
+secmon-$(CONFIG_ARCH_USE_SECURE_MONITOR) += cpu.c
 secmon-$(CONFIG_ARCH_USE_SECURE_MONITOR) += cpu_lib.S
 secmon-$(CONFIG_ARCH_USE_SECURE_MONITOR) += psci.c
 secmon-$(CONFIG_ARCH_USE_SECURE_MONITOR) += uart.c

src/soc/nvidia/tegra132/cpu.c

@@ -60,12 +60,8 @@ static void set_armv8_64bit_reset_vector(uintptr_t entry)
 	write32(0, &pmc->secure_scratch35);
 }
 
-
-void start_cpu(int cpu, void *entry_64)
+void cpu_prepare_startup(void *entry_64)
 {
-	printk(BIOS_DEBUG, "Starting CPU%d @ %p trampolining to %p.\n",
-		cpu, reset_entry_32bit, entry_64);
-
 	/* Warm reset vector is pulled from the PMC scratch registers. */
 	set_armv8_64bit_reset_vector((uintptr_t)entry_64);
 
@@ -75,6 +71,18 @@ void start_cpu(int cpu, void *entry_64)
 	 * to the traompoline location.
 	 */
 	set_armv8_32bit_reset_vector((uintptr_t)reset_entry_32bit);
+}
 
+void start_cpu_silent(int cpu, void *entry_64)
+{
+	cpu_prepare_startup(entry_64);
 	enable_core_clocks(cpu);
 }
+
+void start_cpu(int cpu, void *entry_64)
+{
+	printk(BIOS_DEBUG, "Starting CPU%d @ %p trampolining to %p.\n",
+		cpu, reset_entry_32bit, entry_64);
+
+	start_cpu_silent(cpu, entry_64);
+}

src/soc/nvidia/tegra132/include/soc/cpu.h

@@ -25,8 +25,11 @@
  * should be a 32-bit address.
  */
 void start_cpu(int cpu, void *entry_64);
+/* Start CPU wthout any log messages. */
+void start_cpu_silent(int cpu, void *entry_64);
+/* Prepare SoC for starting a CPU. Initialize the global state of the SoC. */
+void cpu_prepare_startup(void *entry_64);
 
 void reset_entry_32bit(void);
 
 #endif /* __SOC_NVIDIA_TEGRA132_CPU_H__ */
-

src/soc/nvidia/tegra132/psci.c

@@ -18,9 +18,21 @@
  */
 
 #include <arch/psci.h>
+#include <soc/cpu.h>
+
+static void *cpu_on_entry_point;
 
 void psci_soc_init(uintptr_t cpu_on_entry)
 {
+	/*
+	 * Stash secmon entry point for CPUs starting up. The 32-bit reset
+	 * vector register is accessible in < EL3 so one has to attempt to
+	 * plug the potential race for that register being changed out from
+	 * under us. Therefore, we set the appropriate registers here, but
+	 * it is also done on each CPU_ON request.
+	 */
+	cpu_on_entry_point = (void *)cpu_on_entry;
+	cpu_prepare_startup(cpu_on_entry_point);
 }
 
 static size_t children_at_level(int parent_level, uint64_t mpidr)