Re: [PATCH 1/6] ARM: NUC900: Add nuc970 machine support

[Wan Zongshun]

On 2016å06æ29æ 23:19, Arnd Bergmann wrote:
> On Saturday, June 25, 2016 6:37:17 PM CEST Wan Zongshun wrote:
> > NUC970 is a new SoC of Nuvoton nuc900 series, this patch is
> > to add machine file support for it.
> >
> > Signed-off-by: Wan Zongshun <mcuos.com@xxxxxxxxx>
>
> Nice to see some activity on the port!
>
> > ---
> >   arch/arm/mach-w90x900/Kconfig                      |  25 ++++
> >   arch/arm/mach-w90x900/Makefile                     |   3 +
> >   .../mach-w90x900/include/mach/nuc970-regs-gcr.h    |  56 ++++++++
> >   arch/arm/mach-w90x900/mach-nuc970.c                | 144 +++++++++++++++++++++
> >   4 files changed, 228 insertions(+)
> >   create mode 100644 arch/arm/mach-w90x900/include/mach/nuc970-regs-gcr.h
> >   create mode 100644 arch/arm/mach-w90x900/mach-nuc970.c
> >
> > diff --git a/arch/arm/mach-w90x900/Kconfig b/arch/arm/mach-w90x900/Kconfig
> > index 69bab32..050833e 100644
> > --- a/arch/arm/mach-w90x900/Kconfig
> > +++ b/arch/arm/mach-w90x900/Kconfig
> > @@ -15,6 +15,21 @@ config CPU_NUC960
> >   	help
> >   	  Support for NUCP960 of Nuvoton NUC900 CPUs.
> >
> > +config SOC_NUC970
> > +	bool
> > +        select GENERIC_IRQ_CHIP
> > +        select SOC_BUS
> > +        select IRQ_DOMAIN
> > +        select MULTI_IRQ_HANDLER
> > +        select USE_OF
> > +        select HAVE_CLK_PREPARE
> > +        select HAVE_MACH_CLKDEV
> > +	select COMMON_CLK
> > +        select NUC900_TIMER
> > +	help
> > +	  Support for NUCP970 of Nuvoton NUC900 CPUs.
> > +
>
> [style] This looks whitespace damaged, and please sort the line alphabetically.

Sure, changed.

> I see you have done this in a way that is basically compatible with
> CONFIG_ARCH_MULTIPLATFORM, good.
>
> What is HAVE_MACH_CLKDEV for?
>
> > @@ -46,4 +61,14 @@ config MACH_W90N960EVB
> >
> >   endmenu
> >
> > +menu "NUC970 Machines"
> > +
> > +config MACH_NUC970EVB
> > +	bool "Nuvoton NUC970 Evaluation Board"
> > +	select SOC_NUC970
> > +	help
> > +	   Say Y here if you are using the Nuvoton NUC970EVB
> > +
> > +endmenu
>
> I'd leave out this entry, with the way have have structured the code (correctly),
> there is no need to separate SoC-specific code from board specific code, since
> they are the same.

Sure, removed it.

> > diff --git a/arch/arm/mach-w90x900/include/mach/nuc970-regs-gcr.h b/arch/arm/mach-w90x900/include/mach/nuc970-regs-gcr.h
> > new file mode 100644
> > index 0000000..e7eb653
> > --- /dev/null
> > +++ b/arch/arm/mach-w90x900/include/mach/nuc970-regs-gcr.h
>
> Can you move the new headers to arch/arm/mach-w90x900/ directly?
>
> > +static int __init nuc900_restart_init(void)
> > +{
> > +	struct device_node *np;
> > +
> > +	np = of_find_compatible_node(NULL, NULL, "nuvoton,gcr");
> > +	wtcr_addr = of_iomap(np, 0);
> > +	if (!wtcr_addr)
> > +		return -ENODEV;
> > +
> > +	of_node_put(np);
> > +
> > +	return 0;
> > +}
>
> Is this a watchdog node? If it is, the restart logic should just
> move into the watchdog driver.

It is not watchdog node, just be global System control register node.

> > +	if (of_machine_is_compatible("nuvoton,nuc970evb"))
> > +		nuc970_init();
>
> What is this for?

Currently, no used, remove it.

> > +	of_platform_populate(NULL, of_default_bus_match_table, NULL, parent);
>
> We have actually moved away from using the soc_device as using the parent
> for the other devices, just probe them separately. In fact the soc_device
> could be handled by a driver in drivers/soc/nuvoton/

Do you think I should add nuc900 soc driver in this folder?
If I want to add nuc900 soc driver in drivers/soc/nuvoton/, can I keep 
my current dts structure no change, or Must I add a new node name soc {}?

I went through the code:soc-realview.c for reference, but I have no idea
about how to re-structure my dts file to match this type soc driver.

> > +static const char *nuc970_dt_compat[] __initconst = {
> > +	"nuvoton,nuc970evb",
> > +	NULL,
> > +};
> > +
> > +void nuc970_restart(enum reboot_mode mode, const char *cmd)
> > +{
> > +	if (wtcr_addr) {
> > +		while (__raw_readl(wtcr_addr + REG_WRPRTR) != 1) {
> > +			__raw_writel(0x59, wtcr_addr + REG_WRPRTR);
> > +			__raw_writel(0x16, wtcr_addr + REG_WRPRTR);
> > +			__raw_writel(0x88, wtcr_addr + REG_WRPRTR);
> > +		}
> > +
> > +		__raw_writel(1, wtcr_addr + REG_AHBIPRST);
> > +	}
>
> Please use writel() instead of __raw_writel().

Does this change apply to all others drivers? or just machine file to 
use writel()?

> > +	soft_restart(0);
> > +}
> > +
> > +DT_MACHINE_START(nuc970_dt, "Nuvoton nuc970 evb")
> > +	.atag_offset	= 0x100,

Removed it, thanks!

> The .atag_offset can be removed here.
>
> 	Arnd
>
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