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ARM: berlin: add SMP support

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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: Antoine Ténart <antoine.tenart@free-electrons.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
This commit is contained in:
Antoine Ténart 2014-06-04 18:03:42 +02:00 committed by Sebastian Hesselbarth
parent 7171511eae
commit 7b7dfdd2b9
4 changed files with 134 additions and 1 deletions
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3
arch/arm/mach-berlin/Kconfig
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@ -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

3
arch/arm/mach-berlin/Makefile
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@ -1 +1,2 @@
obj-y += berlin.o
obj-y += berlin.o
obj-$(CONFIG_SMP) += headsmp.o platsmp.o

30
arch/arm/mach-berlin/headsmp.S Normal file
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@ -0,0 +1,30 @@
/*
* 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

99
arch/arm/mach-berlin/platsmp.c Normal file
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@ -0,0 +1,99 @@
/*
* 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);