Subject: [PATCHv4 06/33] CLK: omap: add autoidle support

From: [email-masked] (Tero Kristo)
Date: Wed, 31 Jul 2013 13:13:57 +0300

On 07/30/2013 09:56 PM, Nishanth Menon wrote:
> On 07/23/2013 02:20 AM, Tero Kristo wrote:
>> OMAP clk driver now routes some of the basic clocks through own
>> registration routine to allow autoidle support. This routine just
>> checks a couple of device node properties and adds autoidle support
>> if required, and just passes the registration forward to basic clocks.
>
> why not extend standard framework to support autoidle capable clocks OR
> introduce our own clk node which depends on basic clocks?

Was kind of easier this way.

>>
>> Signed-off-by: Tero Kristo <[email-masked]>
>> ---
>>   arch/arm/mach-omap2/clock.c |    6 ++
>>   drivers/clk/omap/Makefile   |    2 +-
>>   drivers/clk/omap/autoidle.c |  130
>> +++++++++++++++++++++++++++++++++++++++++++
>>   drivers/clk/omap/clk.c      |    4 +-
>>   include/linux/clk/omap.h    |    4 ++
>>   5 files changed, 143 insertions(+), 3 deletions(-)
>>   create mode 100644 drivers/clk/omap/autoidle.c
>
> I know it is getting a little stale, but anyways, device tree binding
> missing.
>
>>
>> diff --git a/arch/arm/mach-omap2/clock.c b/arch/arm/mach-omap2/clock.c
>> index 0c38ca9..669d4c4 100644
>> --- a/arch/arm/mach-omap2/clock.c
>> +++ b/arch/arm/mach-omap2/clock.c
> Not sure why, at this point in time we are going to calling drivers/clk
> code.
>
>> @@ -520,6 +520,9 @@ int omap2_clk_enable_autoidle_all(void)
>>       list_for_each_entry(c, &clk_hw_omap_clocks, node)
>>           if (c->ops && c->ops->allow_idle)
>>               c->ops->allow_idle(c);
>> +
>> +    of_omap_clk_allow_autoidle_all();
>> +
>>       return 0;
>>   }
>>
>> @@ -539,6 +542,9 @@ int omap2_clk_disable_autoidle_all(void)
>>       list_for_each_entry(c, &clk_hw_omap_clocks, node)
>>           if (c->ops && c->ops->deny_idle)
>>               c->ops->deny_idle(c);
>> +
>> +    of_omap_clk_deny_autoidle_all();
>> +
>
> these are defined for CONFIG_OF.. anyways, without dt nodes (OMAP3 is
> supposed to support non-DT boot even now), this would not work, would it?

The lists are empty so the funcs do nothing. However, dropping CONFIG_OF 
would break these of course. Will figure out a fix for this.

The calls are needed for the transition phase until we can move more clk 
stuff from mach-omap2 to drivers.

>
>
>>       return 0;
>>   }
>>
>> diff --git a/drivers/clk/omap/Makefile b/drivers/clk/omap/Makefile
>> index 4cad480..ca56700 100644
>> --- a/drivers/clk/omap/Makefile
>> +++ b/drivers/clk/omap/Makefile
>> @@ -1 +1 @@
>> -obj-y                    += clk.o dpll.o
>> +obj-y                    += clk.o dpll.o autoidle.o
>> diff --git a/drivers/clk/omap/autoidle.c b/drivers/clk/omap/autoidle.c
>> new file mode 100644
>> index 0000000..6424cb2
>> --- /dev/null
>> +++ b/drivers/clk/omap/autoidle.c
>> @@ -0,0 +1,130 @@
>> +/*
>> + * OMAP clock autoidle support
>> + *
>> + * Copyright (C) 2013 Texas Instruments, Inc.
>> + *
>> + * Tero Kristo <[email-masked]>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any
>> + * kind, whether express or implied; without even the implied warranty
>> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + */
>> +
>> +#include <linux/clk-provider.h>
>> +#include <linux/module.h>
>> +#include <linux/slab.h>
>> +#include <linux/io.h>
>> +#include <linux/err.h>
>> +#include <linux/string.h>
>> +#include <linux/log2.h>
>> +#include <linux/of.h>
>> +#include <linux/of_address.h>
> at all of these required?

I'll double check.

>
>> +
>> +#ifdef CONFIG_OF
>> +struct clk_omap_autoidle {
>> +    void __iomem        *reg;
>> +    u8            shift;
>> +    u8            flags;
>> +    const char        *name;
>> +    struct list_head    node;
>> +};
>> +
>> +#define AUTOIDLE_LOW        0x1
>> +
>> +static LIST_HEAD(autoidle_clks);
>> +
>> +static void omap_allow_autoidle(struct clk_omap_autoidle *clk)
>> +{
>> +    u32 val;
>> +
>> +    val = readl(clk->reg);
>> +
>> +    if (clk->flags & AUTOIDLE_LOW)
>> +        val &= ~(1 << clk->shift);
>> +    else
>> +        val |= (1 << clk->shift);
>> +
>> +    writel(val, clk->reg);
>> +}
>> +
>> +static void omap_deny_autoidle(struct clk_omap_autoidle *clk)
>> +{
>> +    u32 val;
>> +
>> +    val = readl(clk->reg);
>> +
>> +    if (clk->flags & AUTOIDLE_LOW)
>> +        val |= (1 << clk->shift);
>> +    else
>> +        val &= ~(1 << clk->shift);
>> +
>> +    writel(val, clk->reg);
>> +}
>> +
>> +void of_omap_clk_allow_autoidle_all(void)
>> +{
>> +    struct clk_omap_autoidle *c;
>> +
>> +    list_for_each_entry(c, &autoidle_clks, node)
>> +        omap_allow_autoidle(c);
>> +}
>> +
>> +void of_omap_clk_deny_autoidle_all(void)
>> +{
>> +    struct clk_omap_autoidle *c;
>> +
>> +    list_for_each_entry(c, &autoidle_clks, node)
>> +        omap_deny_autoidle(c);
>> +}
>> +
>> +static __init void of_omap_autoidle_setup(struct device_node *node)
>> +{
>> +    u32 shift;
>> +    void __iomem *reg;
>> +    struct clk_omap_autoidle *clk;
>> +
>> +    if (of_property_read_u32(node, "ti,autoidle-shift", &shift))
>> +        return;
>> +
>> +    reg = of_iomap(node, 0);
>> +
>> +    clk = kzalloc(sizeof(struct clk_omap_autoidle), GFP_KERNEL);
>> +
>> +    if (!clk) {
>> +        pr_err("%s: kzalloc failed\n", __func__);
>> +        return;
>> +    }
>> +
>> +    clk->shift = shift;
>> +    clk->name = node->name;
>> +    clk->reg = reg;
>> +
>> +    if (of_property_read_bool(node, "ti,autoidle-low"))
>> +        clk->flags |= AUTOIDLE_LOW;
>> +
>> +    list_add(&clk->node, &autoidle_clks);
>> +}
>> +
>> +void __init of_omap_divider_setup(struct device_node *node)
>> +{
>> +    of_divider_clk_setup(node);
>> +    of_omap_autoidle_setup(node);
>> +}
>> +EXPORT_SYMBOL_GPL(of_omap_divider_setup);
>> +CLK_OF_DECLARE(omap_autoidle_clock, "divider-clock",
>> of_omap_divider_setup);
>
> This is overriding drivers/clk/clk-divider.c ?

Yea, this declaration here should be removed.

>> +
>> +void __init of_omap_fixed_factor_setup(struct device_node *node)
>> +{
>> +    of_fixed_factor_clk_setup(node);
>> +    of_omap_autoidle_setup(node);
>> +}
>> +EXPORT_SYMBOL_GPL(of_omap_fixed_factor_setup);
>> +CLK_OF_DECLARE(omap_fixed_factor_clock, "fixed-factor-clock",
>> +    of_omap_fixed_factor_setup);
>
> This is overriding drivers/clk/clk-fixed-factor.c ?

Ditto.

>> +
>> +#endif
>> diff --git a/drivers/clk/omap/clk.c b/drivers/clk/omap/clk.c
>> index cd31a81..c149097 100644
>> --- a/drivers/clk/omap/clk.c
>> +++ b/drivers/clk/omap/clk.c
>> @@ -25,8 +25,8 @@ static const struct of_device_id clk_match[] = {
>>       {.compatible = "fixed-clock", .data = of_fixed_clk_setup, },
>>       {.compatible = "mux-clock", .data = of_mux_clk_setup, },
>>       {.compatible = "fixed-factor-clock",
>> -        .data = of_fixed_factor_clk_setup, },
>> -    {.compatible = "divider-clock", .data = of_divider_clk_setup, },
>> +        .data = of_omap_fixed_factor_setup, },
>> +    {.compatible = "divider-clock", .data = of_omap_divider_setup, },

These should be enough for registration.

>>       {.compatible = "gate-clock", .data = of_gate_clk_setup, },
>>       {.compatible = "ti,omap4-dpll-clock", .data =
>> of_omap4_dpll_setup, },
>>       {},
>> diff --git a/include/linux/clk/omap.h b/include/linux/clk/omap.h
>> index c39e775..904bdad 100644
>> --- a/include/linux/clk/omap.h
>> +++ b/include/linux/clk/omap.h
>> @@ -192,5 +192,9 @@ extern const struct clk_hw_omap_ops
>> clkhwops_omap4_dpllmx;
>>   int dt_omap_clk_init(void);
>>   extern void omap_dt_clocks_register(struct omap_dt_clk *oclks, int
>> cnt);
>>   void of_omap4_dpll_setup(struct device_node *node);
>> +void of_omap_fixed_factor_setup(struct device_node *node);
>> +void of_omap_divider_setup(struct device_node *node);
>> +void of_omap_clk_allow_autoidle_all(void);
>> +void of_omap_clk_deny_autoidle_all(void);
>>
>>   #endif
>>
>
> I personally dont prefer the fact that divider-clock and
> fixed-rate-clock now has double meaning - building a multi-arch kernel
> for example, this can wreak havoc. standard definitions should not be
> monkeyed around with thus if avoidable, and in this case, very much
> avoidable.
>
> just my 2 cents.

Yea, as described before, I'll change the code not to make a global 
override, instead, just make omap specific override which parses the 
extra params. That sound better or still see some issues with that?

-Tero