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Message-ID: <20161114145459.63c23391@xhacker>
Date: Mon, 14 Nov 2016 14:54:59 +0800
From: Jisheng Zhang <jszhang@...vell.com>
To: Pankaj Dubey <pankaj.dubey@...sung.com>
CC: Andrew Lunn <andrew@...n.ch>, Heiko Stuebner <heiko@...ech.de>,
<geert+renesas@...der.be>,
Linus Walleij <linus.walleij@...aro.org>,
"Liviu Dudau" <liviu.dudau@....com>,
Patrice Chotard <patrice.chotard@...com>,
Wei Xu <xuwei5@...ilicon.com>,
Michal Simek <michal.simek@...inx.com>, <vireshk@...nel.org>,
<magnus.damm@...il.com>, Russell King <linux@...linux.org.uk>,
<krzk@...nel.org>, <thomas.ab@...sung.com>, <arnd@...db.de>,
Stephen Warren <swarren@...dotorg.org>,
Ray Jui <rjui@...adcom.com>, <rmk+kernel@...linux.org.uk>,
<horms@...ge.net.au>, Jun Nie <jun.nie@...aro.org>,
<linux-arm-kernel@...ts.infradead.org>,
<shiraz.linux.kernel@...il.com>, <linux-kernel@...r.kernel.org>,
"Dinh Nguyen" <dinguyen@...nsource.altera.com>,
Shawn Guo <shawnguo@...nel.org>
Subject: Re: [PATCH 01/16] ARM: scu: Provide support for parsing SCU device
node to enable SCU
On Mon, 14 Nov 2016 14:12:51 +0800 Jisheng Zhang wrote:
> Hi Pankaj,
>
> On Mon, 14 Nov 2016 10:31:56 +0530 Pankaj Dubey wrote:
>
> > Many platforms are duplicating code for enabling SCU, lets add
> > common code to enable SCU by parsing SCU device node so the duplication
> > in each platform can be avoided.
> >
> > CC: Krzysztof Kozlowski <krzk@...nel.org>
> > CC: Jisheng Zhang <jszhang@...vell.com>
> > CC: Russell King <linux@...linux.org.uk>
> > CC: Dinh Nguyen <dinguyen@...nsource.altera.com>
> > CC: Patrice Chotard <patrice.chotard@...com>
> > CC: Linus Walleij <linus.walleij@...aro.org>
> > CC: Liviu Dudau <liviu.dudau@....com>
> > CC: Ray Jui <rjui@...adcom.com>
> > CC: Stephen Warren <swarren@...dotorg.org>
> > CC: Heiko Stuebner <heiko@...ech.de>
> > CC: Shawn Guo <shawnguo@...nel.org>
> > CC: Michal Simek <michal.simek@...inx.com>
> > CC: Wei Xu <xuwei5@...ilicon.com>
> > CC: Andrew Lunn <andrew@...n.ch>
> > CC: Jun Nie <jun.nie@...aro.org>
> > Suggested-by: Arnd Bergmann <arnd@...db.de>
> > Signed-off-by: Pankaj Dubey <pankaj.dubey@...sung.com>
> > ---
> > arch/arm/include/asm/smp_scu.h | 4 +++
> > arch/arm/kernel/smp_scu.c | 56 ++++++++++++++++++++++++++++++++++++++++++
> > 2 files changed, 60 insertions(+)
> >
> > diff --git a/arch/arm/include/asm/smp_scu.h b/arch/arm/include/asm/smp_scu.h
> > index bfe163c..fdeec07 100644
> > --- a/arch/arm/include/asm/smp_scu.h
> > +++ b/arch/arm/include/asm/smp_scu.h
> > @@ -39,8 +39,12 @@ static inline int scu_power_mode(void __iomem *scu_base, unsigned int mode)
> >
> > #if defined(CONFIG_SMP) && defined(CONFIG_HAVE_ARM_SCU)
> > void scu_enable(void __iomem *scu_base);
> > +void __iomem *of_scu_get_base(void);
> > +int of_scu_enable(void);
> > #else
> > static inline void scu_enable(void __iomem *scu_base) {}
> > +static inline void __iomem *of_scu_get_base(void) {return NULL; }
> > +static inline int of_scu_enable(void) {return 0; }
> > #endif
> >
> > #endif
> > diff --git a/arch/arm/kernel/smp_scu.c b/arch/arm/kernel/smp_scu.c
> > index 72f9241..d0ac3ed 100644
> > --- a/arch/arm/kernel/smp_scu.c
> > +++ b/arch/arm/kernel/smp_scu.c
> > @@ -10,6 +10,7 @@
> > */
> > #include <linux/init.h>
> > #include <linux/io.h>
> > +#include <linux/of_address.h>
> >
> > #include <asm/smp_plat.h>
> > #include <asm/smp_scu.h>
> > @@ -70,6 +71,61 @@ void scu_enable(void __iomem *scu_base)
> > */
> > flush_cache_all();
> > }
> > +
> > +static const struct of_device_id scu_match[] = {
> > + { .compatible = "arm,cortex-a9-scu", },
> > + { .compatible = "arm,cortex-a5-scu", },
> > + { }
> > +};
> > +
> > +/*
> > + * Helper API to get SCU base address
> > + * In case platform DT do not have SCU node, or iomap fails
> > + * this call will fallback and will try to map via call to
> > + * scu_a9_get_base.
> > + * This will return ownership of scu_base to the caller
> > + */
> > +void __iomem *of_scu_get_base(void)
> > +{
> > + unsigned long base = 0;
> > + struct device_node *np;
> > + void __iomem *scu_base;
> > +
> > + np = of_find_matching_node(NULL, scu_match);
>
> could we check np before calling of_iomap()?
>
> > + scu_base = of_iomap(np, 0);
> > + of_node_put(np);
> > + if (!scu_base) {
> > + pr_err("%s failed to map scu_base via DT\n", __func__);
>
> For non-ca5, non-ca9 based SoCs, we'll see this error msg. We understand
> what does it mean, but it may confuse normal users. In current version,
> berlin doesn't complain like this for non-ca9 SoCs
oops, I just realized that the non-ca9 berlin arm SoC version isn't upstreamed.
Below is the draft version I planed. Basically speaking, the code tries to
find "arm,cortex-a9-scu" node from DT, if can't, we think we don't need to
worry about SCU. Is there any elegant solution for my situation?
Thanks,
Jisheng
------------8<-------------------
--- a/arch/arm/mach-berlin/platsmp.c
+++ b/arch/arm/mach-berlin/platsmp.c
@@ -56,22 +56,25 @@ static void __init berlin_smp_prepare_cpus(unsigned int max_cpus)
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;
+ if (np) {
+ scu_base = of_iomap(np, 0);
+ of_node_put(np);
+ if (!scu_base)
+ return;
+ scu_enable(scu_base);
+ iounmap(scu_base);
+ }
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;
+ return;
vectors_base = ioremap(CONFIG_VECTORS_BASE, SZ_32K);
if (!vectors_base)
- goto unmap_scu;
+ return;
- scu_enable(scu_base);
flush_cache_all();
/*
@@ -87,8 +90,6 @@ static void __init berlin_smp_prepare_cpus(unsigned int max_cpus)
writel(virt_to_phys(secondary_startup), vectors_base + SW_RESET_ADDR);
iounmap(vectors_base);
-unmap_scu:
- iounmap(scu_base);
}
static struct smp_operations berlin_smp_ops __initdata = {
>
> > + if (scu_a9_has_base()) {
> > + base = scu_a9_get_base();
> > + scu_base = ioremap(base, SZ_4K);
> > + }
> > + if (!scu_base) {
> > + pr_err("%s failed to map scu_base\n", __func__);
>
> ditto
>
> > + return IOMEM_ERR_PTR(-ENOMEM);
> > + }
> > + }
> > + return scu_base;
> > +}
> > +
> > +/*
> > + * Enable SCU via mapping scu_base DT
> > + * If scu_base mapped successfully scu will be enabled and in case of
> > + * failure if will return non-zero error code
> > + */
> > +int of_scu_enable(void)
> > +{
> > + void __iomem *scu_base;
> > +
> > + scu_base = of_scu_get_base();
> > + if (!IS_ERR(scu_base)) {
> > + scu_enable(scu_base);
> > + iounmap(scu_base);
> > + return 0;
> > + }
> > + return PTR_ERR(scu_base);
> > +}
> > +
> > #endif
> >
> > /*
>
>
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