Re: [PATCH v5 07/14] ARM: mvebu: Extend the pmsu registers

[Sebastian Hesselbarth]

On 03/26/2014 10:33 AM, Gregory CLEMENT wrote:
> On 26/03/2014 01:30, Jason Cooper wrote:
> > On Tue, Mar 25, 2014 at 11:48:18PM +0100, Gregory CLEMENT wrote:
> > > The initial binding for PMSU were wrong. It didn't take into account
> > > all the registers from the PMSU and moreover it referred to registers
> > > which are not part of PMSU.
> > >
> > > The Power Management Unit Service block also controls the Coherency
> > > Fabric subsystem. These registers are needed for the CPU idle
> > > implementation for the Armada 370/XP, it allows to enter a deep CPU
> > > idle state where the Coherency Fabric and the L2 cache are powered
> > > down.
> > >
> > > This commit add support for a new compatible for the PMSU node
> > > including the block related to the coherency fabric. It also keeps
> > > compatibility with the old binding
> > >
> > > This patch also adds warnings if one of the base registers set can't
> > > be ioremapped.
> > >
> > > Signed-off-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx>
> > > ---
> > >   arch/arm/mach-mvebu/pmsu.c | 47 +++++++++++++++++++++++++++++++++++++++++-----
> > >   1 file changed, 42 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/arch/arm/mach-mvebu/pmsu.c b/arch/arm/mach-mvebu/pmsu.c
> > > index d71ef53107c4..865bcb651e01 100644
> > > --- a/arch/arm/mach-mvebu/pmsu.c
> > > +++ b/arch/arm/mach-mvebu/pmsu.c
> > > @@ -27,11 +27,21 @@
> > >   static void __iomem *pmsu_mp_base;
> > >   static void __iomem *pmsu_reset_base;
> > >
> > > -#define PMSU_BOOT_ADDR_REDIRECT_OFFSET(cpu)	((cpu * 0x100) + 0x24)
> > > +#define PMSU_BASE_OFFSET    0x100
> > > +#define PMSU_REG_SIZE	    0x1000
> > > +
> > > +#define PMSU_BOOT_ADDR_REDIRECT_OFFSET(cpu)	((cpu * 0x100) + 0x124)
> > >   #define PMSU_RESET_CTL_OFFSET(cpu)		(cpu * 0x8)
> > >
> > >   static struct of_device_id of_pmsu_table[] = {
> > > -	{.compatible = "marvell,armada-370-xp-pmsu"},
> > > +	{
> > > +		.compatible = "marvell,armada-370-pmsu",
> > > +		.data = (void *) false,
> >
> > This looks sketchy to me.
>
> Could you elaborate it?
>
> For a boolean I didn't saw the point to use a pointer.

Isn't the different compatible boolean enough?
You can use of_device_is_compatible() below.

> > > +	},
> > > +	{
> > > +		.compatible = "marvell,armada-370-xp-pmsu",
> > > +		.data = (void *) true, /* legacy */
> >
> > Same.
> >
> > > +	},
> > >   	{ /* end of list */ },
> > >   };
> > >
> > > @@ -59,15 +69,42 @@ int armada_xp_boot_cpu(unsigned int cpu_id, void *boot_addr)
> > >   }
> > >   #endif
> > >
> > > +static void __init armada_370_xp_pmsu_legacy_init(struct device_node *np)
> > > +{
> > > +	u32 addr;
> > > +	pr_warn("*** Warning ***  Using an old binding which will be deprecated\n");
> >
> > This should be noted in the binding docs...

pr_warn(FW_{WARN,BUG} "deprecated pmsu binding\n");

[...]
> > >   	np = of_find_matching_node(NULL, of_pmsu_table);
> > >   	if (np) {
> > > +		const struct of_device_id *match =
> > > +			of_match_node(of_pmsu_table, np);
> > > +		BUG_ON(!match);
> > > +
> > >   		pr_info("Initializing Power Management Service Unit\n");
> > > -		pmsu_mp_base = of_iomap(np, 0);
> > > -		pmsu_reset_base = of_iomap(np, 1);
> > > +
> > > +		if (match->data) /* legacy */
> > > +			armada_370_xp_pmsu_legacy_init(np);

if (of_device_is_compatible(np, "marvell,armada-370-xp-pmsu"))
	armada_370_xp_pmsu_legacy_init(np);
else
	...

Sebastian

> > And if a new compatible string actually needs data passed?
>
> in this case we would have to update the of_pmsu_table, so this
> code could be also updated if needed in the same time. So I don't
> see the problem, maybe I miss something.
>
> But the plan is really to remove this legacy part later (after a
> few kernel release)
>
> > > +		else
> > > +			pmsu_mp_base = of_iomap(np, 0);
> > > +		WARN_ON(!pmsu_mp_base);
> > > +		of_node_put(np);
> > > +
> > > +		/*
> > > +		 * This temporaty hack will be removed as soon as we

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