diff mbox

[v3,1/2] ARM: EXYNOS: Remove static mapping of SCU SFR

Message ID a43af947-6002-bc65-f73b-02d57a78d6cb@samsung.com (mailing list archive)
State New, archived
Headers show

Commit Message

Pankaj Dubey Nov. 10, 2016, 12:37 p.m. UTC
Hi Arnd,

On Thursday 10 November 2016 05:24 PM, Arnd Bergmann wrote:
> On Wednesday, November 9, 2016 5:45:54 PM CET Pankaj Dubey wrote:
>> Lets remove static mapping of SCU SFR mainly used in CORTEX-A9 SoC based
>> boards. Instead use mapping from device tree node of SCU.
>>
>> NOTE: This patch has dependency on DT file of any such CORTEX-A9 SoC
>> based boards, in the absence of SCU device node in DTS file, only single
>> CPU will boot. So if you are using OUT-OF-TREE DTS file of CORTEX-A9 based
>> Exynos SoC make sure to add SCU device node to DTS file for SMP boot.
>>
>> Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
>> Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
> 
> With CONFIG_SMP disabled, I now get this build failure:
> 

Sorry, I missed this part and did not check with CONFIG_SMP disabled.

> arch/arm/mach-exynos/pm.o: In function `exynos_enter_aftr':
> pm.c:(.text.exynos_enter_aftr+0xec): undefined reference to `exynos_scu_enable'
> arch/arm/mach-exynos/suspend.o: In function `exynos_pm_resume':
> suspend.c:(.text.exynos_pm_resume+0x78): undefined reference to `exynos_scu_enable'
> 
> Please fix. I have applied a patch locally (see below), but don't know
> if that is the best solution. As we seem to duplicate that code across
> several platforms, I wonder why we don't just put it into the core scu
> implementation.
> 

When I checked scu_enable declaration it is defined in
arch/arm/include/asm/smp_scu.h as:

#if defined(CONFIG_SMP) && defined(CONFIG_HAVE_ARM_SCU)
void scu_enable(void __iomem *scu_base);
#else
static inline void scu_enable(void __iomem *scu_base) {}
#endif

So if CONFIG_SMP is disable then there is no sense of exynos_scu_enable
as well. So wow about using below patch?

--------------------------------------------------------

Subject: [PATCH] ARM: exynos: fix build fail due to exynos_scu_enable

Build failed if we disable CONFIG_SMP as shown below:

arch/arm/mach-exynos/pm.o: In function `exynos_enter_aftr':
pm.c:(.text.exynos_enter_aftr+0xec): undefined reference to
`exynos_scu_enable'
arch/arm/mach-exynos/suspend.o: In function `exynos_pm_resume':
suspend.c:(.text.exynos_pm_resume+0x78): undefined reference to
`exynos_scu_enable'

Since scu_enable is defined only in case CONFIG_SMP and CONFIG_HAVE_ARM_SCU
lets move exynos_scu_enable also under these two macros.

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
---
 arch/arm/mach-exynos/common.h | 5 +++++
 1 file changed, 5 insertions(+)

  */

Comments

Arnd Bergmann Nov. 10, 2016, 2:07 p.m. UTC | #1
On Thursday, November 10, 2016 6:07:54 PM CET pankaj.dubey wrote:
> On Thursday 10 November 2016 05:24 PM, Arnd Bergmann wrote:
> > On Wednesday, November 9, 2016 5:45:54 PM CET Pankaj Dubey wrote:
> 
> Sorry, I missed this part and did not check with CONFIG_SMP disabled.
> 
> > arch/arm/mach-exynos/pm.o: In function `exynos_enter_aftr':
> > pm.c:(.text.exynos_enter_aftr+0xec): undefined reference to `exynos_scu_enable'
> > arch/arm/mach-exynos/suspend.o: In function `exynos_pm_resume':
> > suspend.c:(.text.exynos_pm_resume+0x78): undefined reference to `exynos_scu_enable'
> > 
> > Please fix. I have applied a patch locally (see below), but don't know
> > if that is the best solution. As we seem to duplicate that code across
> > several platforms, I wonder why we don't just put it into the core scu
> > implementation.
> > 
> 
> When I checked scu_enable declaration it is defined in
> arch/arm/include/asm/smp_scu.h as:
> 
> #if defined(CONFIG_SMP) && defined(CONFIG_HAVE_ARM_SCU)
> void scu_enable(void __iomem *scu_base);
> #else
> static inline void scu_enable(void __iomem *scu_base) {}
> #endif
> 
> So if CONFIG_SMP is disable then there is no sense of exynos_scu_enable
> as well. So wow about using below patch?
> 
> --------------------------------------------------------
> 
> Subject: [PATCH] ARM: exynos: fix build fail due to exynos_scu_enable
> 
> Build failed if we disable CONFIG_SMP as shown below:
> 
> arch/arm/mach-exynos/pm.o: In function `exynos_enter_aftr':
> pm.c:(.text.exynos_enter_aftr+0xec): undefined reference to
> `exynos_scu_enable'
> arch/arm/mach-exynos/suspend.o: In function `exynos_pm_resume':
> suspend.c:(.text.exynos_pm_resume+0x78): undefined reference to
> `exynos_scu_enable'
> 
> Since scu_enable is defined only in case CONFIG_SMP and CONFIG_HAVE_ARM_SCU
> lets move exynos_scu_enable also under these two macros.
> 
> Reported-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
> ---
>  arch/arm/mach-exynos/common.h | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/arch/arm/mach-exynos/common.h b/arch/arm/mach-exynos/common.h
> index fb12d11..03fdb79 100644
> --- a/arch/arm/mach-exynos/common.h
> +++ b/arch/arm/mach-exynos/common.h
> @@ -156,7 +156,12 @@ extern void exynos_cpu_restore_register(void);
>  extern void exynos_pm_central_suspend(void);
>  extern int exynos_pm_central_resume(void);
>  extern void exynos_enter_aftr(void);
> +#if defined(CONFIG_SMP) && defined(CONFIG_HAVE_ARM_SCU)
>  extern int exynos_scu_enable(void);
> +#else
> +static inline void exynos_scu_enable(void) {}
> +#endif

Yes, I think that would work, but you can drop the CONFIG_HAVE_ARM_SCU
check because of

menuconfig ARCH_EXYNOS
        ....
        select HAVE_ARM_SCU if SMP
        ...

> Of-course your idea to move it in core SCU file is also good that we
> lots of duplication in different architecture can be avoided.
> 
> In that case I can think of following patch:
> 
> [PATCH] ARM: scu: use SCU device node to enable SCU
> 
> Many platforms are duplicating code for enabling SCU, lets add
> common code to enable SCU using SCU device node so the duplication in
> each platform can be avoided.
> 
> Suggested-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
> ---

That looks good too. I also checked the other callers of
scu_enable(), and we have only three classes here:

a) of_iomap: berlin, exynos, mvebu, realview, rockchip, socfpga, sti, ux500, vexpress
b) ioremap(scu_a9_get_base()): bcm63xx, bcm, hisi, zx
c) iotable_init, scu_a9_get_base(): imx, omap4, tegra, zynq
d) ioremap(constant): shmobile, spear13xx

I checked that none of the ones in category c) actually use the address early,
so we can easily change four into b).

I also think that we need to keep both a) and b) because the output of
scu_a9_get_base() might be incorrect in some chips, and not all dtb
files have an SCU in them.

If we make the common SCU setup check DT first and then fall back to
scu_a9_get_base(), that means we have covered almost all cases, unless
I'm missing a problem with that approach. It would be nice to
check spear13xx and the Cortex-A9 based mach-shmobile variants
(emev2, r8a7779, and sh73a0) to see if they could also share
that implementation.

	Arnd
Krzysztof Kozlowski Nov. 10, 2016, 4:46 p.m. UTC | #2
On Thu, Nov 10, 2016 at 06:07:54PM +0530, pankaj.dubey wrote:
> So if CONFIG_SMP is disable then there is no sense of exynos_scu_enable
> as well. So wow about using below patch?
> 
> --------------------------------------------------------
> 
> Subject: [PATCH] ARM: exynos: fix build fail due to exynos_scu_enable
> 
> Build failed if we disable CONFIG_SMP as shown below:

This is fine with me.

(...)

> Of-course your idea to move it in core SCU file is also good that we
> lots of duplication in different architecture can be avoided.
> 
> In that case I can think of following patch:
> 
> [PATCH] ARM: scu: use SCU device node to enable SCU
> 
> Many platforms are duplicating code for enabling SCU, lets add
> common code to enable SCU using SCU device node so the duplication in
> each platform can be avoided.
> 
> Suggested-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
> ---
>  arch/arm/include/asm/smp_scu.h |  2 ++
>  arch/arm/kernel/smp_scu.c      | 17 +++++++++++++++++
>  2 files changed, 19 insertions(+)
> 
> diff --git a/arch/arm/include/asm/smp_scu.h b/arch/arm/include/asm/smp_scu.h
> index bfe163c..e5e2492 100644
> --- a/arch/arm/include/asm/smp_scu.h
> +++ b/arch/arm/include/asm/smp_scu.h
> @@ -38,8 +38,10 @@ static inline int scu_power_mode(void __iomem
> *scu_base, unsigned int mode)
>  #endif
> 
>  #if defined(CONFIG_SMP) && defined(CONFIG_HAVE_ARM_SCU)
> +int of_scu_enable(void);
>  void scu_enable(void __iomem *scu_base);
>  #else
> +static inline int of_scu_enable(void) {return 0;}
>  static inline void scu_enable(void __iomem *scu_base) {}
>  #endif
> 
> diff --git a/arch/arm/kernel/smp_scu.c b/arch/arm/kernel/smp_scu.c
> index 72f9241..7c16d16 100644
> --- a/arch/arm/kernel/smp_scu.c
> +++ b/arch/arm/kernel/smp_scu.c
> @@ -34,6 +34,23 @@ unsigned int __init scu_get_core_count(void __iomem
> *scu_base)
>  	return (ncores & 0x03) + 1;
>  }
> 
> +int of_scu_enable(void)
> +{
> +	struct device_node *np;
> +	void __iomem *scu_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) {
> +		pr_err("%s failed to map scu_base\n", __func__);
> +		return -ENOMEM;
> +	}
> +	scu_enable(scu_base);
> +	iounmap(scu_base);
> +	return 0;
> +}
> +
>  /*
>   * Enable the SCU
>   */
> -- 
> 
> 
> Followed by cleanup in various architecture where this piece of code is
> duplicated and all of them can call directly of_scu_enable()

This looks better to me.

> 
> 
> Please let me know which one you will prefer for fixing build issue.
> 
> @Krzysztof, please let me know if I need to resubmit SCU series again
> with fix or you will accept build fix patch on top of already taken patch.

The code is already in my next/soc branch and I prefer to avoid
rebasing/dropping commits so how about:
1. Creating a generic wrapper which arm-soc will apply,
2. Provide me a tag with it (by arm-soc folks),
3. Fix the Exynos !SMP build on top of the tag (by using generic
   approach).

Arnd,
Are you fine with this?

Best regards,
Krzysztof
diff mbox

Patch

diff --git a/arch/arm/mach-exynos/common.h b/arch/arm/mach-exynos/common.h
index fb12d11..03fdb79 100644
--- a/arch/arm/mach-exynos/common.h
+++ b/arch/arm/mach-exynos/common.h
@@ -156,7 +156,12 @@  extern void exynos_cpu_restore_register(void);
 extern void exynos_pm_central_suspend(void);
 extern int exynos_pm_central_resume(void);
 extern void exynos_enter_aftr(void);
+#if defined(CONFIG_SMP) && defined(CONFIG_HAVE_ARM_SCU)
 extern int exynos_scu_enable(void);
+#else
+static inline void exynos_scu_enable(void) {}
+#endif
+

------------------------------------------------------

Of-course your idea to move it in core SCU file is also good that we
lots of duplication in different architecture can be avoided.

In that case I can think of following patch:

[PATCH] ARM: scu: use SCU device node to enable SCU

Many platforms are duplicating code for enabling SCU, lets add
common code to enable SCU using SCU device node so the duplication in
each platform can be avoided.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
---
 arch/arm/include/asm/smp_scu.h |  2 ++
 arch/arm/kernel/smp_scu.c      | 17 +++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/arch/arm/include/asm/smp_scu.h b/arch/arm/include/asm/smp_scu.h
index bfe163c..e5e2492 100644
--- a/arch/arm/include/asm/smp_scu.h
+++ b/arch/arm/include/asm/smp_scu.h
@@ -38,8 +38,10 @@  static inline int scu_power_mode(void __iomem
*scu_base, unsigned int mode)
 #endif

 #if defined(CONFIG_SMP) && defined(CONFIG_HAVE_ARM_SCU)
+int of_scu_enable(void);
 void scu_enable(void __iomem *scu_base);
 #else
+static inline int of_scu_enable(void) {return 0;}
 static inline void scu_enable(void __iomem *scu_base) {}
 #endif

diff --git a/arch/arm/kernel/smp_scu.c b/arch/arm/kernel/smp_scu.c
index 72f9241..7c16d16 100644
--- a/arch/arm/kernel/smp_scu.c
+++ b/arch/arm/kernel/smp_scu.c
@@ -34,6 +34,23 @@  unsigned int __init scu_get_core_count(void __iomem
*scu_base)
 	return (ncores & 0x03) + 1;
 }

+int of_scu_enable(void)
+{
+	struct device_node *np;
+	void __iomem *scu_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) {
+		pr_err("%s failed to map scu_base\n", __func__);
+		return -ENOMEM;
+	}
+	scu_enable(scu_base);
+	iounmap(scu_base);
+	return 0;
+}
+
 /*
  * Enable the SCU