[PATCH 2/3] ARM: keystone: Enable SMP support on Keystone machines

[Chander Kashyap]

2013/6/11 Santosh Shilimkar <santosh.shilimkar at ti.com>:
> Add basic SMP support for Keystone machines. This does not
> include support for CPU hotplug for now.
>
> Cc: Olof Johansson <olof at lixom.net>
> Cc: Arnd Bergmann <arnd at arndb.de>
> Cc: arm at kernel.org
>
> Signed-off-by: Santosh Shilimkar <santosh.shilimkar at ti.com>
> ---
>  arch/arm/mach-keystone/Kconfig    |    1 +
>  arch/arm/mach-keystone/Makefile   |    1 +
>  arch/arm/mach-keystone/keystone.c |    4 +++
>  arch/arm/mach-keystone/keystone.h |   17 ++++++++++
>  arch/arm/mach-keystone/platsmp.c  |   67 +++++++++++++++++++++++++++++++++++++
>  5 files changed, 90 insertions(+)
>  create mode 100644 arch/arm/mach-keystone/keystone.h
>  create mode 100644 arch/arm/mach-keystone/platsmp.c
>
> diff --git a/arch/arm/mach-keystone/Kconfig b/arch/arm/mach-keystone/Kconfig
> index 39fab74..6054673 100644
> --- a/arch/arm/mach-keystone/Kconfig
> +++ b/arch/arm/mach-keystone/Kconfig
> @@ -3,6 +3,7 @@ config ARCH_KEYSTONE
>         select CPU_V7
>         select ARM_GIC
>         select HAVE_ARM_ARCH_TIMER
> +       select HAVE_SMP
>         select USE_OF
>         select MULTI_IRQ_HANDLER
>         select CLKSRC_MMIO
> diff --git a/arch/arm/mach-keystone/Makefile b/arch/arm/mach-keystone/Makefile
> index d4671d5..3f6b8ab 100644
> --- a/arch/arm/mach-keystone/Makefile
> +++ b/arch/arm/mach-keystone/Makefile
> @@ -1 +1,2 @@
>  obj-y                                  := keystone.o
> +obj-$(CONFIG_SMP)                      += platsmp.o
> diff --git a/arch/arm/mach-keystone/keystone.c b/arch/arm/mach-keystone/keystone.c
> index 6c6fc42..5dd3b32 100644
> --- a/arch/arm/mach-keystone/keystone.c
> +++ b/arch/arm/mach-keystone/keystone.c
> @@ -19,6 +19,9 @@
>  #include <asm/mach/map.h>
>  #include <asm/mach/arch.h>
>  #include <asm/mach/time.h>
> +#include <asm/smp_plat.h>
> +
> +#include "keystone.h"
>
>  #define PLL_RESET_WRITE_KEY_MASK               0xffff0000
>  #define PLL_RESET_WRITE_KEY                    0x5a69
> @@ -67,6 +70,7 @@ void keystone_restart(char mode, const char *cmd)
>  }
>
>  DT_MACHINE_START(KEYSTONE, "Keystone")
> +       .smp            = smp_ops(keystone_smp_ops),
>         .map_io         = debug_ll_io_init,
>         .init_machine   = keystone_init,
>         .dt_compat      = keystone_match,
> diff --git a/arch/arm/mach-keystone/keystone.h b/arch/arm/mach-keystone/keystone.h
> new file mode 100644
> index 0000000..43a1b47
> --- /dev/null
> +++ b/arch/arm/mach-keystone/keystone.h
> @@ -0,0 +1,17 @@
> +/*
> + * Copyright 2013 Texas Instruments, Inc.
> + *     Cyril Chemparathy <cyril at ti.com>
> + *     Santosh Shilimkar <santosh.shillimkar at ti.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + */
> +
> +#ifndef __KEYSTONE_H__
> +#define __KEYSTONE_H__
> +
> +extern struct smp_operations keystone_smp_ops;
> +extern void secondary_startup(void);
> +
> +#endif /* __KEYSTONE_H__ */
> diff --git a/arch/arm/mach-keystone/platsmp.c b/arch/arm/mach-keystone/platsmp.c
> new file mode 100644
> index 0000000..3071dda
> --- /dev/null
> +++ b/arch/arm/mach-keystone/platsmp.c
> @@ -0,0 +1,67 @@
> +/*
> + * Keystone SOC SMP platform code
> + *
> + * Copyright 2013 Texas Instruments, Inc.
> + *     Cyril Chemparathy <cyril at ti.com>
> + *     Santosh Shilimkar <santosh.shillimkar at ti.com>
> + *
> + * Based on platsmp.c, Copyright (C) 2002 ARM Ltd.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + */
> +
> +#include <linux/init.h>
> +#include <linux/smp.h>
> +#include <linux/io.h>
> +
> +#include <asm/smp_plat.h>
> +
> +#include "keystone.h"
> +
> +static void __init keystone_smp_init_cpus(void)
> +{
> +       unsigned int i, ncores;
> +
> +       ncores = 4;
This hardcoding can be done away, if cpu nodes are passed through DT.
Also set set_cpu_possible will be done by "arm_dt_init_cpu_maps" in  devtree.c

> +
> +       /* sanity check */
> +       if (ncores > NR_CPUS) {
> +               pr_warn("restricted to %d cpus\n", NR_CPUS);
> +               ncores = NR_CPUS;
> +       }
> +
> +       for (i = 0; i < ncores; i++)
> +               set_cpu_possible(i, true);
> +}
> +
> +static int __cpuinit keystone_smp_boot_secondary(unsigned int cpu,
> +                                               struct task_struct *idle)
> +{
> +       unsigned long start = virt_to_phys(&secondary_startup);
> +       int error;
> +
> +       pr_debug("keystone-smp: booting cpu %d, vector %08lx\n",
> +                cpu, start);
> +
> +       asm volatile (
> +               "mov    r0, #0\n"       /* power on cmd */
> +               "mov    r1, %1\n"       /* cpu          */
> +               "mov    r2, %2\n"       /* start        */
> +               ".inst  0xe1600070\n"   /* smc #0       */
> +               "mov    %0, r0\n"
> +               : "=r" (error)
> +               : "r"(cpu), "r"(start)
> +               : "cc", "r0", "r1", "r2", "memory"
> +       );
> +
> +       pr_debug("keystone-smp: monitor returned %d\n", error);
> +
> +       return error;
> +}
> +
> +struct smp_operations keystone_smp_ops __initdata = {
> +       .smp_init_cpus          = keystone_smp_init_cpus,
> +       .smp_boot_secondary     = keystone_smp_boot_secondary,
> +};
> --
> 1.7.9.5
>
>
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--
with warm regards,
Chander Kashyap