Commit 5420b4b1 authored by Linus Walleij's avatar Linus Walleij
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ARM: realview: add an DT SMP boot method 



This adds an SMP boot method for the ARM RealView reference
designs. We also select HAVE_SMP by default and make it use
SMP_ON_UP so we only need to support one single kernel across
the RealView reference designs when using DT.

The RealViews need to have the SCU (Snoop Control Unit)
activated on boot, and this is now done by looking up its
address from the device tree and initializing it and counting
the available cores.

The RealViews boot by using a magic address register in the
system controller (SYS_FLAGS) to store the boot address,
the ROM will then read this register to the PC when the CPUs
are taken out of WFI. This code uses a handle to the syscon
regmap to access this register.

Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent ca5b21fa

Documentation/devicetree/bindings/arm/cpus.txt

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Original line number Diff line number Diff line
@@ -190,6 +190,7 @@ nodes to be present and contain the properties described below. 
			    "allwinner,sun6i-a31"

			    "allwinner,sun8i-a23"

			    "arm,psci"

			    "arm,realview-smp"

			    "brcm,brahma-b15"

			    "marvell,armada-375-smp"

			    "marvell,armada-380-smp"

arch/arm/mach-realview/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -5,11 +5,13 @@ config REALVIEW_DT 
	bool "Support RealView(R) Device Tree based boot"

	select ARM_GIC

	select CLK_SP810

	select HAVE_SMP

	select ICST

	select MFD_SYSCON

	select POWER_RESET

	select POWER_RESET_VERSATILE

	select POWER_SUPPLY

	select SMP_ON_UP

	select SOC_REALVIEW

	select USE_OF

	help

arch/arm/mach-realview/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -3,7 +3,7 @@ 
#



obj-y					:= core.o

obj-$(CONFIG_REALVIEW_DT)		+= realview-dt.o

obj-$(CONFIG_REALVIEW_DT)		+= realview-dt.o platsmp-dt.o

obj-$(CONFIG_MACH_REALVIEW_EB)		+= realview_eb.o

obj-$(CONFIG_MACH_REALVIEW_PB11MP)	+= realview_pb11mp.o

obj-$(CONFIG_MACH_REALVIEW_PB1176)	+= realview_pb1176.o

arch/arm/mach-realview/platsmp-dt.c

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Original line number Diff line number Diff line 
/*

 * Copyright (C) 2015 Linus Walleij

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 */

#include <linux/smp.h>

#include <linux/io.h>

#include <linux/of.h>

#include <linux/of_address.h>

#include <linux/regmap.h>

#include <linux/mfd/syscon.h>



#include <asm/cacheflush.h>

#include <asm/smp_plat.h>

#include <asm/smp_scu.h>



#include <plat/platsmp.h>



#include "core.h"



#define REALVIEW_SYS_FLAGSSET_OFFSET	0x30



static const struct of_device_id realview_scu_match[] = {

	{ .compatible = "arm,arm11mp-scu", },

	{ .compatible = "arm,cortex-a9-scu", },

	{ .compatible = "arm,cortex-a5-scu", },

	{ }

};



static const struct of_device_id realview_syscon_match[] = {

        { .compatible = "arm,core-module-integrator", },

        { .compatible = "arm,realview-eb-syscon", },

        { .compatible = "arm,realview-pb11mp-syscon", },

        { .compatible = "arm,realview-pbx-syscon", },

        { },

};



static void __init realview_smp_prepare_cpus(unsigned int max_cpus)

{

	struct device_node *np;

	void __iomem *scu_base;

	struct regmap *map;

	unsigned int ncores;

	int i;



	np = of_find_matching_node(NULL, realview_scu_match);

	if (!np) {

		pr_err("PLATSMP: No SCU base address\n");

		return;

	}

	scu_base = of_iomap(np, 0);

	of_node_put(np);

	if (!scu_base) {

		pr_err("PLATSMP: No SCU remap\n");

		return;

	}



	scu_enable(scu_base);

	ncores = scu_get_core_count(scu_base);

	pr_info("SCU: %d cores detected\n", ncores);

	for (i = 0; i < ncores; i++)

		set_cpu_possible(i, true);

	iounmap(scu_base);



	/* The syscon contains the magic SMP start address registers */

	np = of_find_matching_node(NULL, realview_syscon_match);

	if (!np) {

		pr_err("PLATSMP: No syscon match\n");

		return;

	}

	map = syscon_node_to_regmap(np);

	if (IS_ERR(map)) {

		pr_err("PLATSMP: No syscon regmap\n");

		return;

	}

	/* Put the boot address in this magic register */

	regmap_write(map, REALVIEW_SYS_FLAGSSET_OFFSET,

		     virt_to_phys(versatile_secondary_startup));

}



struct smp_operations realview_dt_smp_ops __initdata = {

	.smp_prepare_cpus	= realview_smp_prepare_cpus,

	.smp_secondary_init	= versatile_secondary_init,

	.smp_boot_secondary	= versatile_boot_secondary,

#ifdef CONFIG_HOTPLUG_CPU

	.cpu_die		= realview_cpu_die,

#endif

};

CPU_METHOD_OF_DECLARE(realview_smp, "arm,realview-smp", &realview_dt_smp_ops);

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