tegra132: add spin table support

Until PSCI is functional the other core still needs to be
brought up in the kernel. The kernel boots these cpus with
the spin table which is just an address in memory to monitor
a jump location.

BUG=chrome-os-partner:31545
BRANCH=None
TEST=Built and brought up secondary core in linux.

Change-Id: Iaa69110f6a647d8fd4149119d97db4fc45d7da00
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 01ca36685852bc5dd85fd4015c8a1e600e23e7ca
Original-Change-Id: Ieaf19cd70aff3e6c8de932e04b1b5aba71822a97
Original-Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/214777
Original-Reviewed-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: http://review.coreboot.org/9021
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

3 files changed, 102 insertions, 1 deletions

diff --git a/src/soc/nvidia/tegra132/Makefile.inc b/src/soc/nvidia/tegra132/Makefile.inc
index 447963970c..261e570f73 100644
--- a/src/soc/nvidia/tegra132/Makefile.inc
+++ b/src/soc/nvidia/tegra132/Makefile.inc
@@ -69,6 +69,7 @@ ramstage-y += ../tegra/gpio.c
 ramstage-y += ../tegra/i2c.c
 ramstage-y += ../tegra/pinmux.c
 ramstage-y += ramstage.c
+ramstage-y += spintable.S
 ramstage-y += mmu_operations.c
 ramstage-$(CONFIG_DRIVERS_UART) += uart.c
 ramstage-y += ../tegra/usb.c
diff --git a/src/soc/nvidia/tegra132/soc.c b/src/soc/nvidia/tegra132/soc.c
index 024fd805da..16001f9fb3 100644
--- a/src/soc/nvidia/tegra132/soc.c
+++ b/src/soc/nvidia/tegra132/soc.c
@@ -18,10 +18,13 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include <string.h>
 #include <console/console.h>
 #include <device/device.h>
 #include <arch/io.h>
 #include <arch/cpu.h>
+#include <arch/cache.h>
+#include <cbmem.h>
 #include <timer.h>
 #include <vendorcode/google/chromeos/chromeos.h>
 #include <soc/addressmap.h>
@@ -62,12 +65,69 @@ static void soc_read_resources(device_t dev)
 
 static volatile int secondary_cpu_up;
 
+static void *spintable_entry;
+static uint64_t * const spintable_magic = (void *)(uintptr_t)0x80000008;
+
+static void spintable_init(void)
+{
+	extern void __wait_for_spin_table_request(void);
+	const size_t spintable_entry_size = 4096;
+
+	spintable_entry =
+		cbmem_add(0x11111111, spintable_entry_size);
+
+	memcpy(spintable_entry, __wait_for_spin_table_request,
+		spintable_entry_size);
+
+	/* Ensure the memory location is zero'd out. */
+	*spintable_magic = 0;
+
+	dcache_clean_invalidate_by_mva(spintable_magic,
+					sizeof(*spintable_magic));
+	dcache_clean_invalidate_by_mva(&spintable_entry,
+					sizeof(spintable_entry));
+	dcache_clean_invalidate_by_mva(spintable_entry, spintable_entry_size);
+	dsb();
+}
+
+static void spintable_wait(void)
+{
+	uint32_t sctlr_el2;
+	uint32_t spsr_el3;
+	uint32_t scr_el3;
+
+	sctlr_el2 = raw_read_sctlr_el2();
+	/* Make sure EL2 is in little endian without any caching enabled. */
+	sctlr_el2 &= ~(1 << 25);
+	sctlr_el2 &= ~(1 << 19);
+	sctlr_el2 &= ~(1 << 12);
+	sctlr_el2 &= ~0xf;
+	raw_write_sctlr_el2(sctlr_el2);
+	/* Ensure enter into EL2t with interrupts disabled. */
+	spsr_el3 = (1 << 9) | (0xf << 6) | (1 << 3);
+	raw_write_spsr_el3(spsr_el3);
+	raw_write_elr_el3((uintptr_t)spintable_entry);
+	/*
+	 * Lower exception level is 64 bit. HVC and SMC allowed. EL0 and EL1
+	 * in non-secure mode. No interrupts routed to EL3.
+	 */
+	scr_el3 = raw_read_scr_el3();
+	scr_el3 |= (1 << 10) | (1 << 8) | (0x3 << 4) | (1 << 0);
+	scr_el3 &= ~((0x7 << 1) | (1 << 7) | (1 << 9) | (1 << 13) | (1 << 12));
+	raw_write_scr_el3(scr_el3);
+	isb();
+	asm volatile(
+		"mov	x0, %0\n\t"
+		"eret\n\t" : : "r" (spintable_magic) : "x0" );
+}
+
 void soc_secondary_cpu_init(void)
 {
 	printk(BIOS_INFO, "CPU%d is up!\n", smp_processor_id());
 	gic_init();
 	dmb();
 	secondary_cpu_up = 1;
+	spintable_wait();
 }
 
 static void start_secondary_cpu(void)
@@ -104,8 +164,10 @@ static void soc_init(device_t dev)
 	clock_init_arm_generic_timer();
 	gic_init();
 
-	if (config->bring_up_secondary_cpu)
+	if (config->bring_up_secondary_cpu) {
+		spintable_init();
 		start_secondary_cpu();
+	}
 }
 
 static void soc_noop(device_t dev)
diff --git a/src/soc/nvidia/tegra132/spintable.S b/src/soc/nvidia/tegra132/spintable.S
new file mode 100644
index 0000000000..3066b7e679
--- /dev/null
+++ b/src/soc/nvidia/tegra132/spintable.S
@@ -0,0 +1,38 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2014 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <arch/asm.h>
+
+ENTRY(__wait_for_spin_table_request)
+	/* Entry here is in EL2 with the magic address in x0. */
+	mov	x28, x0
+1:
+	ldr	x27, [x28]
+	cmp	x27, xzr
+	b.ne	2f
+	wfe
+	b	1b
+2:
+	/* Entry into the kernel. */
+	mov	x0, xzr
+	mov	x1, xzr
+	mov	x2, xzr
+	mov	x3, xzr
+	br	x27
+ENDPROC(__wait_for_spin_table_request)