ARM: tango4: Initial platform support

Support Sigma Designs ARM-based (specifically, Cortex-A9 MPCore r3p0)
Tango4 "Secure Media Processor" platforms: smp8756, smp8758, smp8759
(8756 is single-core, the latter are dual-core).

Note: 8758 vs 8759: same chip, different package.

Support for older MIPS-based platforms can be found elsewhere:
https://github.com/mansr/linux-tangox

Signed-off-by: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>

MAINTAINERS

@@ -1588,6 +1588,13 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/mcoquelin/stm32.git
 N:	stm32
 F:	drivers/clocksource/armv7m_systick.c
 
+ARM/TANGO ARCHITECTURE
+M:	Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
+L:	linux-arm-kernel@lists.infradead.org
+S:	Maintained
+F:	arch/arm/mach-tango/
+F:	arch/arm/boot/dts/tango*
+
 ARM/TECHNOLOGIC SYSTEMS TS7250 MACHINE SUPPORT
 M:	Lennert Buytenhek <kernel@wantstofly.org>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)

arch/arm/Kconfig

@@ -919,6 +919,8 @@ source "arch/arm/mach-sunxi/Kconfig"
 
 source "arch/arm/mach-prima2/Kconfig"
 
+source "arch/arm/mach-tango/Kconfig"
+
 source "arch/arm/mach-tegra/Kconfig"
 
 source "arch/arm/mach-u300/Kconfig"

arch/arm/Makefile

@@ -211,6 +211,7 @@ machine-$(CONFIG_ARCH_SOCFPGA)		+= socfpga
 machine-$(CONFIG_ARCH_STI)		+= sti
 machine-$(CONFIG_ARCH_STM32)		+= stm32
 machine-$(CONFIG_ARCH_SUNXI)		+= sunxi
+machine-$(CONFIG_ARCH_TANGO)		+= tango
 machine-$(CONFIG_ARCH_TEGRA)		+= tegra
 machine-$(CONFIG_ARCH_U300)		+= u300
 machine-$(CONFIG_ARCH_U8500)		+= ux500

arch/arm/mach-tango/Kconfig

@@ -0,0 +1,12 @@
+config ARCH_TANGO
+	bool "Sigma Designs Tango4 (SMP87xx)" if 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

arch/arm/mach-tango/Makefile

@@ -0,0 +1,2 @@
+asflags-y += -mcpu=cortex-a9
+obj-y += setup.o smc.o

arch/arm/mach-tango/setup.c

@@ -0,0 +1,31 @@
+#include <linux/smp.h>
+#include <asm/mach/arch.h>
+#include <asm/hardware/cache-l2x0.h>
+#include "smc.h"
+
+static int tango4_boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+	tango_set_aux_boot_addr(virt_to_phys(secondary_startup));
+	tango_start_aux_core(cpu);
+	return 0;
+}
+
+static struct smp_operations tango4_smp_ops __initdata = {
+	.smp_boot_secondary	= tango4_boot_secondary,
+};
+
+CPU_METHOD_OF_DECLARE(tango4_smp, "sigma,tango4-smp", &tango4_smp_ops);
+
+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

arch/arm/mach-tango/smc.S

@@ -0,0 +1,9 @@
+#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)

arch/arm/mach-tango/smc.h

@@ -0,0 +1,5 @@
+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((unsigned int)val, 0x105)