linux-kernel - Re: [PATCH v2 4/5] ARM: EXYNOS: add exynos_get_boot

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Date:	Wed, 18 Mar 2015 16:21:33 +0100
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Cc:	Kukjin Kim <kgene.kim@...sung.com>, Kukjin Kim <kgene@...nel.org>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Tomasz Figa <tomasz.figa@...il.com>,
	Colin Cross <ccross@...gle.com>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	linux-samsung-soc@...r.kernel.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Russell King <rmk+kernel@....linux.org.uk>
Subject: Re: [PATCH v2 4/5] ARM: EXYNOS: add exynos_get_boot_addr() helper

On śro, 2015-03-18 at 16:18 +0100, Bartlomiej Zolnierkiewicz wrote:
> On Wednesday, March 18, 2015 02:43:49 PM Krzysztof Kozlowski wrote:
> > 2015-03-18 14:09 GMT+01:00 Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>:
> > > Add get_cpu_boot_addr() firmware operation and then
> > > exynos_get_boot_addr() helper.
> > >
> > > This is a preparation for adding coupled cpuidle support
> > > for Exynos3250 SoC.
> > >
> > > There should be no functional changes caused by this patch.
> > >
> > > Cc: Daniel Lezcano <daniel.lezcano@...aro.org>
> > > Cc: Russell King <rmk+kernel@....linux.org.uk>
> > > Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
> > > ---
> > >  arch/arm/include/asm/firmware.h |  4 ++++
> > >  arch/arm/mach-exynos/firmware.c | 17 +++++++++++++++++
> > >  arch/arm/mach-exynos/platsmp.c  | 25 +++++++++++++++++++++++++
> > >  3 files changed, 46 insertions(+)
> > >
> > > diff --git a/arch/arm/include/asm/firmware.h b/arch/arm/include/asm/firmware.h
> > > index 89aefe1..34c1d96 100644
> > > --- a/arch/arm/include/asm/firmware.h
> > > +++ b/arch/arm/include/asm/firmware.h
> > > @@ -34,6 +34,10 @@ struct firmware_ops {
> > >          */
> > >         int (*set_cpu_boot_addr)(int cpu, unsigned long boot_addr);
> > >         /*
> > > +        * Gets boot address of specified physical CPU
> > > +        */
> > > +       int (*get_cpu_boot_addr)(int cpu, unsigned long *boot_addr);
> > > +       /*
> > >          * Boots specified physical CPU
> > >          */
> > >         int (*cpu_boot)(int cpu);
> > > diff --git a/arch/arm/mach-exynos/firmware.c b/arch/arm/mach-exynos/firmware.c
> > > index f236877..c9e4481 100644
> > > --- a/arch/arm/mach-exynos/firmware.c
> > > +++ b/arch/arm/mach-exynos/firmware.c
> > > @@ -104,6 +104,22 @@ static int exynos_set_cpu_boot_addr(int cpu, unsigned long boot_addr)
> > >         return 0;
> > >  }
> > >
> > > +static int exynos_get_cpu_boot_addr(int cpu, unsigned long *boot_addr)
> > > +{
> > > +       void __iomem *boot_reg;
> > > +
> > > +       if (!sysram_ns_base_addr)
> > > +               return -ENODEV;
> > > +
> > > +       boot_reg = sysram_ns_base_addr + 0x1c;
> > > +
> > > +       if (soc_is_exynos4412())
> > > +               boot_reg += 4 * cpu;
> > > +
> > > +       *boot_addr = __raw_readl(boot_reg);
> > > +       return 0;
> > > +}
> > > +
> > >  static int exynos_cpu_suspend(unsigned long arg)
> > >  {
> > >         flush_cache_all();
> > > @@ -138,6 +154,7 @@ static int exynos_resume(void)
> > >  static const struct firmware_ops exynos_firmware_ops = {
> > >         .do_idle                = IS_ENABLED(CONFIG_EXYNOS_CPU_SUSPEND) ? exynos_do_idle : NULL,
> > >         .set_cpu_boot_addr      = exynos_set_cpu_boot_addr,
> > > +       .get_cpu_boot_addr      = exynos_get_cpu_boot_addr,
> > >         .cpu_boot               = exynos_cpu_boot,
> > >         .suspend                = IS_ENABLED(CONFIG_PM_SLEEP) ? exynos_suspend : NULL,
> > >         .resume                 = IS_ENABLED(CONFIG_EXYNOS_CPU_SUSPEND) ? exynos_resume : NULL,
> > > diff --git a/arch/arm/mach-exynos/platsmp.c b/arch/arm/mach-exynos/platsmp.c
> > > index b7cfcdc..449edd1 100644
> > > --- a/arch/arm/mach-exynos/platsmp.c
> > > +++ b/arch/arm/mach-exynos/platsmp.c
> > > @@ -272,6 +272,31 @@ fail:
> > >         return ret;
> > >  }
> > >
> > > +static int exynos_get_boot_addr(u32 core_id, unsigned long *boot_addr)
> > > +{
> > > +       int ret;
> > > +
> > > +       /*
> > > +        * Try to get boot address using firmware first
> > > +        * and fall back to boot register if it fails.
> > > +        */
> > > +       ret = call_firmware_op(get_cpu_boot_addr, core_id, boot_addr);
> > > +       if (ret && ret != -ENOSYS)
> > > +               goto fail;
> > 
> > The exynos_get_cpu_boot_addr() returns ENODEV. Do you really want to
> > check for ENOSYS here?
> 
> Yes.  When secure firmware is not present on the board the call_firmware_op()
> itself returns -ENOSYS (exynos_get_cpu_boot_addr() is not called in this
> case) and it needs to be handled in a special way.

Right, my mistake. Rest looks good:

Reviewed-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>

Best regards,
Krzysztof




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