Re: [PATCH v3 9/9] ARM: add initial support for Marvell Berlin SoCs

[Sebastian Hesselbarth]

On 11/07/13 06:40, Jisheng Zhang wrote:
> On Tue, 5 Nov 2013 06:28:43 -0800
> Sebastian Hesselbarth <sebastian.hesselbarth@xxxxxxxxx> wrote:
>
> > This adds initial support for the Marvell Berlin SoC family with
> > Armada 1500 (88DE3100) and Armada 1500-mini (88DE3005) SoCs.
> >
> > Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@xxxxxxxxx>
> > Reviewed-by: Jason Cooper <jason@xxxxxxxxxxxxxx>
> > Reviewed-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
> > Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx>
> > ---
[...]
> > diff --git a/arch/arm/mach-berlin/Kconfig b/arch/arm/mach-berlin/Kconfig
> > new file mode 100644
> > index 0000000..c5b39b1
> > --- /dev/null
> > +++ b/arch/arm/mach-berlin/Kconfig
> > @@ -0,0 +1,30 @@
> > +config ARCH_BERLIN
> > +	bool "Marvell Berlin SoCs" if ARCH_MULTI_V7
> > +	select GENERIC_CLOCKEVENTS
> > +	select GENERIC_IRQ_CHIP
> > +	select COMMON_CLK
> > +	select DW_APB_ICTL
> > +	select DW_APB_TIMER_OF
> > +
> > +if ARCH_BERLIN
> > +
> > +menu "Marvell Berlin SoC variants"
> > +
> > +config MACH_BERLIN_BG2
> > +	bool "Marvell Armada 1500 (BG2)"
> > +	select ARM_GIC
> ARM_GIC is common on berlin SoCs. we can put it below ARCH_BERLIN?

Sure, I guess BG3 is also using GIC?

> > +	select CACHE_L2X0
> ditto

You already re-replied to that. I leave L2X0 here, BG3 will be
different, as you stated.

> > +	select CPU_PJ4B
> > +	select HAVE_ARM_TWD
> > +	select HAVE_SMP
> > +
> > +config MACH_BERLIN_BG2CD
> > +	bool "Marvell Armada 1500-mini (BG2CD)"
> > +	select ARM_GIC
> > +	select CACHE_L2X0
> > +	select CPU_V7
> > +	select HAVE_ARM_TWD
> BG2CD is single core, I'm not sure it have twd. I will check with SoC people.
> But can twd be really used in single CA9 system?

From a quick view into Cortex-A9 MPCore TRM, I cannot see why it
shouldn't be there even for single-core. If you can get more info,
that would be great.

Actually, IIRC smp_twd does not compile without SMP set, so the above
should at least be 'HAVE_ARM_TWD if SMP'. If you shrink MULTI_V7 down
to non-SMP cores, you can disable it and it will fail to compile.

> > +
> > +endmenu
> > +
> > +endif
> > diff --git a/arch/arm/mach-berlin/Makefile b/arch/arm/mach-berlin/Makefile
> > new file mode 100644
> > index 0000000..ab69fe9
> > --- /dev/null
> > +++ b/arch/arm/mach-berlin/Makefile
> > @@ -0,0 +1 @@
> > +obj-y += berlin.o
> > diff --git a/arch/arm/mach-berlin/berlin.c b/arch/arm/mach-berlin/berlin.c
> > new file mode 100644
> > index 0000000..16c2942
> > --- /dev/null
> > +++ b/arch/arm/mach-berlin/berlin.c
> > @@ -0,0 +1,39 @@
> > +/*
> > + * Device Tree support for Marvell Berlin SoCs.
> > + *
> > + * Sebastian Hesselbarth <sebastian.hesselbarth@xxxxxxxxx>
> > + *
> > + * based on GPL'ed 2.6 kernel sources
> > + *  (c) Marvell International Ltd.
> > + *
> > + * This file is licensed under the terms of the GNU General Public
> > + * License version 2.  This program is licensed "as is" without any
> > + * warranty of any kind, whether express or implied.
> > + */
> > +
> > +#include <linux/init.h>
> > +#include <linux/io.h>
> > +#include <linux/kernel.h>
> > +#include <linux/of_platform.h>
> > +#include <asm/hardware/cache-l2x0.h>
> > +#include <asm/mach/arch.h>
> > +
> > +static void __init berlin_init_machine(void)
> > +{
> > +	/*
> > +	 * with DT probing for L2CCs, berlin_init_machine can be removed.
> > +	 * Note: 88DE3005 (Armada 1500-mini) uses pl310 l2cc
> > +	 */
> > +	l2x0_of_init(0x70c00000, 0xfeffffff);
> Per my experience, put l2x0 initialization in init_machine is too late. It
> did cause some boot stability problems during our product massive bootup test.
> In our internal 3.10.y tree, we put it in init_early, I also suggest we do
> this too in mainline.

Ok.

> > +	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
> If l2 initialization is put in init_early, this is not needed any more.

Right, that's already in the comment right above l2x0_of_init ;)

> > +}
> > +
> > +static const char * const berlin_dt_compat[] = {
> > +	"marvell,berlin",
> > +	NULL,
> > +};
> > +
> > +DT_MACHINE_START(BERLIN_DT, "Marvell Berlin")
> > +	.dt_compat      = berlin_dt_compat,
> > +	.init_machine   = berlin_init_machine,
> > +MACHINE_END

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