Re: [PATCH v2 16/20] ARM: mmp: add SMP support

From: Florian Fainelli
Date: Thu Aug 22 2019 - 12:36:49 EST


On 8/22/19 2:26 AM, Lubomir Rintel wrote:
> Used to bring up the second core on MMP3.
>
> Signed-off-by: Lubomir Rintel <lkundrak@xxxxx>
>
> ---
> Changes since v1:
> - Wrap SW_BRANCH_VIRT_ADDR with __pa_symbol()
>
> arch/arm/mach-mmp/Makefile | 3 +++
> arch/arm/mach-mmp/platsmp.c | 33 +++++++++++++++++++++++++++++++++
> 2 files changed, 36 insertions(+)
> create mode 100644 arch/arm/mach-mmp/platsmp.c
>
> diff --git a/arch/arm/mach-mmp/Makefile b/arch/arm/mach-mmp/Makefile
> index 322c1c97dc900..7b3a7f979eece 100644
> --- a/arch/arm/mach-mmp/Makefile
> +++ b/arch/arm/mach-mmp/Makefile
> @@ -22,6 +22,9 @@ ifeq ($(CONFIG_PM),y)
> obj-$(CONFIG_CPU_PXA910) += pm-pxa910.o
> obj-$(CONFIG_CPU_MMP2) += pm-mmp2.o
> endif
> +ifeq ($(CONFIG_SMP),y)
> +obj-$(CONFIG_MACH_MMP3_DT) += platsmp.o
> +endif
>
> # board support
> obj-$(CONFIG_MACH_ASPENITE) += aspenite.o
> diff --git a/arch/arm/mach-mmp/platsmp.c b/arch/arm/mach-mmp/platsmp.c
> new file mode 100644
> index 0000000000000..98d5ef23623cb
> --- /dev/null
> +++ b/arch/arm/mach-mmp/platsmp.c
> @@ -0,0 +1,33 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2019 Lubomir Rintel <lkundrak@xxxxx>
> + */
> +#include <linux/io.h>
> +#include <asm/smp_scu.h>
> +#include <asm/smp.h>
> +#include "addr-map.h"
> +
> +#define SW_BRANCH_VIRT_ADDR CIU_REG(0x24)
> +
> +static int mmp3_boot_secondary(unsigned int cpu, struct task_struct *idle)
> +{
> + /*
> + * Apparently, the boot ROM on the second core spins on this
> + * register becoming non-zero and then jumps to the address written
> + * there. No IPIs involved.
> + */
> + __raw_writel(virt_to_phys(secondary_startup),
> + __pa_symbol(SW_BRANCH_VIRT_ADDR));


That looks wrong, the __pa_symbol() is applicable to secondary_startup,
while SW_BRANCH_VIRT_ADDR does not need that.

> + return 0;
> +}
> +
> +static void mmp3_smp_prepare_cpus(unsigned int max_cpus)
> +{
> + scu_enable(SCU_VIRT_BASE);
> +}
> +
> +static const struct smp_operations mmp3_smp_ops __initconst = {
> + .smp_prepare_cpus = mmp3_smp_prepare_cpus,
> + .smp_boot_secondary = mmp3_boot_secondary,
> +};
> +CPU_METHOD_OF_DECLARE(mmp3_smp, "marvell,mmp3-smp", &mmp3_smp_ops);
>


--
Florian