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

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Message-ID: <53329EFE.4040705@free-electrons.com>
Date:	Wed, 26 Mar 2014 10:33:50 +0100
From:	Gregory CLEMENT <gregory.clement@...e-electrons.com>
To:	Jason Cooper <jason@...edaemon.net>
CC:	Daniel Lezcano <daniel.lezcano@...aro.org>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>, linux-pm@...r.kernel.org,
	Andrew Lunn <andrew@...n.ch>,
	Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>,
	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
	Ezequiel Garcia <ezequiel.garcia@...e-electrons.com>,
	linux-arm-kernel@...ts.infradead.org,
	Lior Amsalem <alior@...vell.com>,
	Tawfik Bayouk <tawfik@...vell.com>,
	Nadav Haklai <nadavh@...vell.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 07/14] ARM: mvebu: Extend the pmsu registers

Hi Jason,

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@...e-electrons.com>
>> ---
>>  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.

> 
>> +	},
>> +	{
>> +		.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...
> 
>> +	/* We just need the adress, we already know the size */
> 
> nit. s/adress/address/

Thanks

> 
>> +	addr = be32_to_cpu(*of_get_address(np, 0, NULL, NULL));
>> +	addr -= PMSU_BASE_OFFSET;
>> +	pmsu_mp_base = ioremap(addr, PMSU_REG_SIZE);
>> +	of_node_put(np);
>> +}
>> +
>>  static int __init armada_370_xp_pmsu_init(void)
>>  {
>>  	struct device_node *np;
>> -
> 
> Please leave this empty line.
> 

OK


>>  	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);
> 
> 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
> 
> nit. s/temporaty/temporary/

Thanks

> 
> thx,
> 
> Jason.
> 
>> +		 * get the proper reset controler support
>> +		 */
>> +		np = of_find_compatible_node(NULL, NULL, "marvell,armada-xp-cpu-reset");
>> +		pmsu_reset_base = of_iomap(np, 0);
>> +		WARN_ON(!pmsu_reset_base);
>>  		of_node_put(np);
>>  	}
>>  
>> -- 
>> 1.8.1.2
>>


-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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