v4.19.13 snapshot.
diff --git a/arch/arm/mach-tango/Kconfig b/arch/arm/mach-tango/Kconfig
new file mode 100644
index 0000000..25b2fd4
--- /dev/null
+++ b/arch/arm/mach-tango/Kconfig
@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: GPL-2.0
+config ARCH_TANGO
+ bool "Sigma Designs Tango4 (SMP87xx)"
+ depends on ARCH_MULTI_V7
+ # Cortex-A9 MPCore r3p0, PL310 r3p2
+ select ARCH_HAS_HOLES_MEMORYMODEL
+ select ARM_ERRATA_754322
+ select ARM_ERRATA_764369 if SMP
+ select ARM_ERRATA_775420
+ select ARM_GIC
+ select CLKSRC_TANGO_XTAL
+ select HAVE_ARM_SCU
+ select HAVE_ARM_TWD
+ select TANGO_IRQ
diff --git a/arch/arm/mach-tango/Makefile b/arch/arm/mach-tango/Makefile
new file mode 100644
index 0000000..da6c633
--- /dev/null
+++ b/arch/arm/mach-tango/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0
+plus_sec := $(call as-instr,.arch_extension sec,+sec)
+AFLAGS_smc.o := -Wa,-march=armv7-a$(plus_sec)
+
+obj-y += setup.o smc.o
+obj-$(CONFIG_SMP) += platsmp.o
+obj-$(CONFIG_SUSPEND) += pm.o
diff --git a/arch/arm/mach-tango/platsmp.c b/arch/arm/mach-tango/platsmp.c
new file mode 100644
index 0000000..65012af
--- /dev/null
+++ b/arch/arm/mach-tango/platsmp.c
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+#include "smc.h"
+
+static int tango_boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+ tango_set_aux_boot_addr(__pa_symbol(secondary_startup));
+ tango_start_aux_core(cpu);
+ return 0;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * cpu_kill() and cpu_die() run concurrently on different cores.
+ * Firmware will only "kill" a core once it has properly "died".
+ * Try a few times to kill a core before giving up, and sleep
+ * between tries to give that core enough time to die.
+ */
+static int tango_cpu_kill(unsigned int cpu)
+{
+ int i, err;
+
+ for (i = 0; i < 10; ++i) {
+ msleep(10);
+ err = tango_aux_core_kill(cpu);
+ if (!err)
+ return true;
+ }
+
+ return false;
+}
+
+static void tango_cpu_die(unsigned int cpu)
+{
+ while (tango_aux_core_die(cpu) < 0)
+ cpu_relax();
+
+ panic("cpu %d failed to die\n", cpu);
+}
+#endif
+
+static const struct smp_operations tango_smp_ops __initconst = {
+ .smp_boot_secondary = tango_boot_secondary,
+#ifdef CONFIG_HOTPLUG_CPU
+ .cpu_kill = tango_cpu_kill,
+ .cpu_die = tango_cpu_die,
+#endif
+};
+
+CPU_METHOD_OF_DECLARE(tango4_smp, "sigma,tango4-smp", &tango_smp_ops);
diff --git a/arch/arm/mach-tango/pm.c b/arch/arm/mach-tango/pm.c
new file mode 100644
index 0000000..028e50c
--- /dev/null
+++ b/arch/arm/mach-tango/pm.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/init.h>
+#include <linux/suspend.h>
+#include <asm/suspend.h>
+#include "smc.h"
+
+static int tango_pm_powerdown(unsigned long arg)
+{
+ tango_suspend(__pa_symbol(cpu_resume));
+
+ return -EIO; /* tango_suspend has failed */
+}
+
+static int tango_pm_enter(suspend_state_t state)
+{
+ if (state == PM_SUSPEND_MEM)
+ return cpu_suspend(0, tango_pm_powerdown);
+
+ return -EINVAL;
+}
+
+static const struct platform_suspend_ops tango_pm_ops = {
+ .enter = tango_pm_enter,
+ .valid = suspend_valid_only_mem,
+};
+
+static int __init tango_pm_init(void)
+{
+ suspend_set_ops(&tango_pm_ops);
+ return 0;
+}
+
+late_initcall(tango_pm_init);
diff --git a/arch/arm/mach-tango/setup.c b/arch/arm/mach-tango/setup.c
new file mode 100644
index 0000000..677dd7b
--- /dev/null
+++ b/arch/arm/mach-tango/setup.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <asm/mach/arch.h>
+#include <asm/hardware/cache-l2x0.h>
+#include "smc.h"
+
+static void tango_l2c_write(unsigned long val, unsigned int reg)
+{
+ if (reg == L2X0_CTRL)
+ tango_set_l2_control(val);
+}
+
+static const char *const tango_dt_compat[] = { "sigma,tango4", NULL };
+
+DT_MACHINE_START(TANGO_DT, "Sigma Tango DT")
+ .dt_compat = tango_dt_compat,
+ .l2c_aux_mask = ~0,
+ .l2c_write_sec = tango_l2c_write,
+MACHINE_END
diff --git a/arch/arm/mach-tango/smc.S b/arch/arm/mach-tango/smc.S
new file mode 100644
index 0000000..361a8dc
--- /dev/null
+++ b/arch/arm/mach-tango/smc.S
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/linkage.h>
+
+ENTRY(tango_smc)
+ push {lr}
+ mov ip, r1
+ dsb /* This barrier is probably unnecessary */
+ smc #0
+ pop {pc}
+ENDPROC(tango_smc)
diff --git a/arch/arm/mach-tango/smc.h b/arch/arm/mach-tango/smc.h
new file mode 100644
index 0000000..455ce3e
--- /dev/null
+++ b/arch/arm/mach-tango/smc.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+extern int tango_smc(unsigned int val, unsigned int service);
+
+#define tango_set_l2_control(val) tango_smc(val, 0x102)
+#define tango_start_aux_core(val) tango_smc(val, 0x104)
+#define tango_set_aux_boot_addr(val) tango_smc(val, 0x105)
+#define tango_suspend(val) tango_smc(val, 0x120)
+#define tango_aux_core_die(val) tango_smc(val, 0x121)
+#define tango_aux_core_kill(val) tango_smc(val, 0x122)