linux-kernel - Re: [PATCH v3 2/4] ARM: EXYNOS: add code for setting/clearing boot flag

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Date:	Wed, 18 Mar 2015 15:23:59 +0100
From:	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
To:	Krzysztof Kozlowski <k.kozlowski@...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>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	linux-samsung-soc@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/4] ARM: EXYNOS: add code for setting/clearing boot flag

On Wednesday, March 18, 2015 02:33:54 PM Krzysztof Kozlowski wrote:
> 2015-03-18 13:51 GMT+01:00 Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>:
> > This code is needed for cpuidle (W-)AFTR mode support on Exynos3250.
> >
> > Cc: Daniel Lezcano <daniel.lezcano@...aro.org>
> > Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
> > Acked-by: Kyungmin Park <kyungmin.park@...sung.com>
> > ---
> >  arch/arm/mach-exynos/common.h |  6 ++++++
> >  arch/arm/mach-exynos/exynos.c | 25 +++++++++++++++++++++++++
> >  2 files changed, 31 insertions(+)
> >
> > diff --git a/arch/arm/mach-exynos/common.h b/arch/arm/mach-exynos/common.h
> > index f70eca7..87bf1f3 100644
> > --- a/arch/arm/mach-exynos/common.h
> > +++ b/arch/arm/mach-exynos/common.h
> > @@ -119,6 +119,12 @@ extern void __iomem *sysram_base_addr;
> >  extern void __iomem *pmu_base_addr;
> >  void exynos_sysram_init(void);
> >
> > +/* CPU BOOT mode flag */
> > +#define C2_STATE       (1 << 3)
> 
> Is this "C2_STATE" like ACPI C2 state? It looks specific to Exynos3250
> boot loader so maybe describe its real purpose?

According to my knowledge it is not like ACPI C2 but my knowledge is
limited since this state is not documented anywhere.  I can add a comment
about it being currently limited to Exynos3250 though.

> > +
> > +void exynos_set_boot_flag(unsigned int cpu, unsigned int mode);
> > +void exynos_clear_boot_flag(unsigned int cpu, unsigned int mode);
> > +
> >  enum {
> >         FW_DO_IDLE_SLEEP,
> >         FW_DO_IDLE_AFTR,
> > diff --git a/arch/arm/mach-exynos/exynos.c b/arch/arm/mach-exynos/exynos.c
> > index 4031a96..90ed2e5 100644
> > --- a/arch/arm/mach-exynos/exynos.c
> > +++ b/arch/arm/mach-exynos/exynos.c
> > @@ -117,6 +117,31 @@ static void __init exynos_init_late(void)
> >         exynos_pm_init();
> >  }
> >
> > +#define REG_CPU_STATE_ADDR     (sysram_ns_base_addr + 0x28)
> > +#define BOOT_MODE_MASK         0x1f
> > +
> > +void exynos_set_boot_flag(unsigned int cpu, unsigned int mode)
> > +{
> > +       unsigned int tmp;
> > +
> > +       tmp = __raw_readl(REG_CPU_STATE_ADDR + cpu * 4);
> > +
> > +       if (mode & BOOT_MODE_MASK)
> > +               tmp &= ~BOOT_MODE_MASK;
> > +
> > +       tmp |= mode;
> > +       __raw_writel(tmp, REG_CPU_STATE_ADDR + cpu * 4);
> > +}
> > +
> > +void exynos_clear_boot_flag(unsigned int cpu, unsigned int mode)
> > +{
> > +       unsigned int tmp;
> > +
> > +       tmp = __raw_readl(REG_CPU_STATE_ADDR + cpu * 4);
> > +       tmp &= ~mode;
> > +       __raw_writel(tmp, REG_CPU_STATE_ADDR + cpu * 4);
> > +}
> > +
> 
> Shouldn't these to functions be put in firmware.c? The
> exynos_set_cpu_boot_addr() is there already. It would be consistent to
> have them in one place.

I can move it to firmware.c if this is desired.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

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