Commit 7b7dfdd2 authored by Antoine Ténart's avatar Antoine Ténart Committed by Sebastian Hesselbarth
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ARM: berlin: add SMP support 



Adds SMP support for Berlin SoCs. Secondary CPUs are reset, then
execute the instruction we put in the reset exception register, setting
the pc at the address contained in the software reset address register,
which is the physical address of the Berlin secondary startup.

This implementation avoid using the pen lock mechanism.

Signed-off-by: default avatarAntoine Ténart <antoine.tenart@free-electrons.com>
Reviewed-by: default avatarAndrew Lunn <andrew@lunn.ch>
Signed-off-by: default avatarSebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
parent 7171511e

arch/arm/mach-berlin/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -15,7 +15,9 @@ config MACH_BERLIN_BG2 
	bool "Marvell Armada 1500 (BG2)"

	select CACHE_L2X0

	select CPU_PJ4B

	select HAVE_ARM_SCU if SMP

	select HAVE_ARM_TWD if SMP

	select HAVE_SMP

	select PINCTRL_BERLIN_BG2



config MACH_BERLIN_BG2CD
@@ -27,6 +29,7 @@ config MACH_BERLIN_BG2CD 
config MACH_BERLIN_BG2Q

	bool "Marvell Armada 1500 Pro (BG2-Q)"

	select CACHE_L2X0

	select HAVE_ARM_SCU if SMP

	select HAVE_ARM_TWD if SMP

	select PINCTRL_BERLIN_BG2Q

arch/arm/mach-berlin/Makefile

+2 −1
Original line number Diff line number Diff line 
obj-y			+= berlin.o

obj-$(CONFIG_SMP)	+= headsmp.o platsmp.o

arch/arm/mach-berlin/headsmp.S

0 → 100644
+30 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2014 Marvell Technology Group Ltd.

 *

 * Antoine Ténart <antoine.tenart@free-electrons.com>

 *

 * 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/linkage.h>

#include <linux/init.h>

#include <asm/assembler.h>



ENTRY(berlin_secondary_startup)

 ARM_BE8(setend be)

	bl	v7_invalidate_l1

	b       secondary_startup

ENDPROC(berlin_secondary_startup)



/*

 * If the following instruction is set in the reset exception vector, CPUs

 * will fetch the value of the software reset address vector when being

 * reset.

 */

.global boot_inst

boot_inst:

	ldr	pc, [pc, #140]



	.align

arch/arm/mach-berlin/platsmp.c

0 → 100644
+99 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2014 Marvell Technology Group Ltd.

 *

 * Antoine Ténart <antoine.tenart@free-electrons.com>

 *

 * 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/io.h>

#include <linux/delay.h>

#include <linux/of.h>

#include <linux/of_address.h>



#include <asm/cacheflush.h>

#include <asm/smp_plat.h>

#include <asm/smp_scu.h>



#define CPU_RESET		0x00



#define RESET_VECT		0x00

#define SW_RESET_ADDR		0x94



extern void berlin_secondary_startup(void);

extern u32 boot_inst;



static void __iomem *cpu_ctrl;



static inline void berlin_perform_reset_cpu(unsigned int cpu)

{

	u32 val;



	val = readl(cpu_ctrl + CPU_RESET);

	val |= BIT(cpu_logical_map(cpu));

	writel(val, cpu_ctrl + CPU_RESET);

}



static int berlin_boot_secondary(unsigned int cpu, struct task_struct *idle)

{

	if (!cpu_ctrl)

		return -EFAULT;



	/*

	 * Reset the CPU, making it to execute the instruction in the reset

	 * exception vector.

	 */

	berlin_perform_reset_cpu(cpu);



	return 0;

}



static void __init berlin_smp_prepare_cpus(unsigned int max_cpus)

{

	struct device_node *np;

	void __iomem *scu_base;

	void __iomem *vectors_base;



	np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu");

	scu_base = of_iomap(np, 0);

	of_node_put(np);

	if (!scu_base)

		return;



	np = of_find_compatible_node(NULL, NULL, "marvell,berlin-cpu-ctrl");

	cpu_ctrl = of_iomap(np, 0);

	of_node_put(np);

	if (!cpu_ctrl)

		goto unmap_scu;



	vectors_base = ioremap(CONFIG_VECTORS_BASE, SZ_32K);

	if (!vectors_base)

		goto unmap_scu;



	scu_enable(scu_base);

	flush_cache_all();



	/*

	 * Write the first instruction the CPU will execute after being reset

	 * in the reset exception vector.

	 */

	writel(boot_inst, vectors_base + RESET_VECT);



	/*

	 * Write the secondary startup address into the SW reset address

	 * vector. This is used by boot_inst.

	 */

	writel(virt_to_phys(berlin_secondary_startup), vectors_base + SW_RESET_ADDR);



	iounmap(vectors_base);

unmap_scu:

	iounmap(scu_base);

}



static struct smp_operations berlin_smp_ops __initdata = {

	.smp_prepare_cpus	= berlin_smp_prepare_cpus,

	.smp_boot_secondary	= berlin_boot_secondary,

};

CPU_METHOD_OF_DECLARE(berlin_smp, "marvell,berlin-smp", &berlin_smp_ops);

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