linux-kernel - Re: [PATCH v3 06/16] soc: mediatek: pm-domains: Add SMI block as bus protection block

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Date:   Fri, 30 Oct 2020 11:56:14 +0100
From:   Enric Balletbo i Serra <enric.balletbo@...labora.com>
To:     Nicolas Boichat <drinkcat@...omium.org>
Cc:     lkml <linux-kernel@...r.kernel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Hsin-Yi Wang <hsinyi@...omium.org>,
        Collabora Kernel ML <kernel@...labora.com>,
        Fabien Parent <fparent@...libre.com>,
        Weiyi Lu <weiyi.lu@...iatek.com>,
        Matthias Brugger <mbrugger@...e.com>,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>
Subject: Re: [PATCH v3 06/16] soc: mediatek: pm-domains: Add SMI block as bus
 protection block

Hi Nicolas,

Thank you for your comments.

On 27/10/20 3:44, Nicolas Boichat wrote:
> On Tue, Oct 27, 2020 at 1:55 AM Enric Balletbo i Serra
> <enric.balletbo@...labora.com> wrote:
>>
>> From: Matthias Brugger <mbrugger@...e.com>
>>
>> Apart from the infracfg block, the SMI block is used to enable the bus
>> protection for some power domains. Add support for this block.
>>
>> Signed-off-by: Matthias Brugger <mbrugger@...e.com>
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
>> ---
>>
>> Changes in v3:
>> - Do not reuse bpd for 2 different things.
>> - Disable pd->smi first and after that pd->infracfg.
>> - Rename BUT_PROT_UPDATE_MT8173 to BUS_PROT_UPDATE_TOPAXI as in all the
>>   other SoCs TOPAXI is mapped to the same address.
>>
> [snip]
>>  static int scpsys_power_on(struct generic_pm_domain *genpd)
>> @@ -266,6 +271,10 @@ generic_pm_domain *scpsys_add_one_domain(struct scpsys *scpsys, struct device_no
>>         if (IS_ERR(pd->infracfg))
>>                 pd->infracfg = NULL;
>>
>> +       pd->smi = syscon_regmap_lookup_by_phandle(node, "mediatek,smi");
>> +       if (IS_ERR(pd->smi))
>> +               pd->smi = NULL;
> 
> This is the second time I see this pattern, I think.
> 
> Do we want to create a new syscon_regmap_lookup_by_phandle_optional wrapper?
> 

I think could be useful, yes. So I sent a patch to add this wrapper, let's see
what the MFD maintainers think.

> Also, are we ok with ignoring all errors? I agree we can ignore
> -ENODEV if optional, but I'm not sure about the others.
> 

Right, we shouldn't ignore the other errors.

>> +
>>         pd->num_clks = of_clk_get_parent_count(node);
>>         if (pd->num_clks > 0) {
>>                 pd->clks = devm_kcalloc(scpsys->dev, pd->num_clks, sizeof(*pd->clks), GFP_KERNEL);
>> diff --git a/drivers/soc/mediatek/mtk-pm-domains.h b/drivers/soc/mediatek/mtk-pm-domains.h
>> index e428fe23a7e3..7b1abcfc4ba3 100644
>> --- a/drivers/soc/mediatek/mtk-pm-domains.h
>> +++ b/drivers/soc/mediatek/mtk-pm-domains.h
>> @@ -34,8 +34,31 @@
>>
>>  #define SPM_MAX_BUS_PROT_DATA          3
>>
>> +#define _BUS_PROT(_mask, _set, _clr, _sta, _update) {  \
>> +               .bus_prot_mask = (_mask),               \
>> +               .bus_prot_set = _set,                   \
>> +               .bus_prot_clr = _clr,                   \
>> +               .bus_prot_sta = _sta,                   \
>> +               .bus_prot_reg_update = _update,         \
>> +       }
>> +
>> +#define BUS_PROT_WR(_mask, _set, _clr, _sta)           \
>> +               _BUS_PROT(_mask, _set, _clr, _sta, false)
>> +
>> +#define BUS_PROT_UPDATE(_mask, _set, _clr, _sta)               \
>> +               _BUS_PROT(_mask, _set, _clr, _sta, true)
>> +
>> +#define BUS_PROT_UPDATE_TOPAXI(_mask)                          \
>> +               BUS_PROT_UPDATE(_mask,                          \
>> +                               INFRA_TOPAXI_PROTECTEN,         \
>> +                               INFRA_TOPAXI_PROTECTEN_CLR,     \
>> +                               INFRA_TOPAXI_PROTECTSTA1)
>> +
>>  struct scpsys_bus_prot_data {
>>         u32 bus_prot_mask;
>> +       u32 bus_prot_set;
>> +       u32 bus_prot_clr;
>> +       u32 bus_prot_sta;
>>         bool bus_prot_reg_update;
>>  };
>>
>> @@ -47,6 +70,7 @@ struct scpsys_bus_prot_data {
>>   * @sram_pdn_ack_bits: The mask for sram power control acked bits.
>>   * @caps: The flag for active wake-up action.
>>   * @bp_infracfg: bus protection for infracfg subsystem
>> + * @bp_smi: bus protection for smi subsystem
>>   */
>>  struct scpsys_domain_data {
>>         u32 sta_mask;
>> @@ -55,6 +79,7 @@ struct scpsys_domain_data {
>>         u32 sram_pdn_ack_bits;
>>         u8 caps;
>>         const struct scpsys_bus_prot_data bp_infracfg[SPM_MAX_BUS_PROT_DATA];
>> +       const struct scpsys_bus_prot_data bp_smi[SPM_MAX_BUS_PROT_DATA];
>>  };
>>
>>  struct scpsys_soc_data {
>> --
>> 2.28.0
>>