linux-kernel - Re: [PATCH V5 12/16] dt-bindings: reset: mediatek: Add infra

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Message-ID: <c56464d3-d33d-1797-2c98-67bec34df756@collabora.com>
Date:   Mon, 2 May 2022 10:54:57 +0200
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Rex-BC Chen <rex-bc.chen@...iatek.com>,
        mturquette@...libre.com, sboyd@...nel.org, matthias.bgg@...il.com,
        robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org
Cc:     p.zabel@...gutronix.de, chun-jie.chen@...iatek.com,
        wenst@...omium.org, runyang.chen@...iatek.com,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org,
        Project_Global_Chrome_Upstream_Group@...iatek.com
Subject: Re: [PATCH V5 12/16] dt-bindings: reset: mediatek: Add infra_ao reset
 bit for MT8195

Il 29/04/22 23:13, Krzysztof Kozlowski ha scritto:
> On 28/04/2022 13:56, Rex-BC Chen wrote:
>> To support reset of infra_ao, add the bit definitions for MT8195.
>> The infra_ao reset includes 5 banks and 32 bits for each bank.
>>
>> Signed-off-by: Rex-BC Chen <rex-bc.chen@...iatek.com>
>> ---
>>   include/dt-bindings/reset/mt8195-resets.h | 170 ++++++++++++++++++++++
>>   1 file changed, 170 insertions(+)
>>
>> diff --git a/include/dt-bindings/reset/mt8195-resets.h b/include/dt-bindings/reset/mt8195-resets.h
>> index a26bccc8b957..463114014483 100644
>> --- a/include/dt-bindings/reset/mt8195-resets.h
>> +++ b/include/dt-bindings/reset/mt8195-resets.h
>> @@ -7,6 +7,7 @@
>>   #ifndef _DT_BINDINGS_RESET_CONTROLLER_MT8195
>>   #define _DT_BINDINGS_RESET_CONTROLLER_MT8195
>>   
>> +/* TOPRGU resets */
>>   #define MT8195_TOPRGU_CONN_MCU_SW_RST          0
>>   #define MT8195_TOPRGU_INFRA_GRST_SW_RST        1
>>   #define MT8195_TOPRGU_APU_SW_RST               2
>> @@ -26,4 +27,173 @@
>>   
>>   #define MT8195_TOPRGU_SW_RST_NUM               16
>>   
>> +/* INFRA RST0 */
>> +#define MT8195_INFRA_RST0_THERM_CTRL_SWRST	0
>> +#define MT8195_INFRA_RST0_RSV0			1
>> +#define MT8195_INFRA_RST0_DISP_PWM1_SWRST	2
>> +#define MT8195_INFRA_RST0_RSV1			3
>> +#define MT8195_INFRA_RST0_MSDC3_SWRST		4
>> +#define MT8195_INFRA_RST0_MSDC2_SWRST		5
>> +#define MT8195_INFRA_RST0_MSDC1_SWRST		6
>> +#define MT8195_INFRA_RST0_MSDC0_SWRST		7
>> +#define MT8195_INFRA_RST0_RSV2			8
>> +#define MT8195_INFRA_RST0_AP_DMA_SWRST		9
>> +#define MT8195_INFRA_RST0_MIPI_D_SWRST		10
>> +#define MT8195_INFRA_RST0_RSV3			11
>> +#define MT8195_INFRA_RST0_RSV4			12
>> +#define MT8195_INFRA_RST0_SSUSB_TOP_SWRST	13
>> +#define MT8195_INFRA_RST0_DISP_PWM_SWRST	14
>> +#define MT8195_INFRA_RST0_AUXADC_SWRST		15
>> +#define MT8195_INFRA_RST0_RSV5			16
>> +#define MT8195_INFRA_RST0_RSV6			17
>> +#define MT8195_INFRA_RST0_RSV7			18
>> +#define MT8195_INFRA_RST0_RSV8			19
>> +#define MT8195_INFRA_RST0_RSV9			20
>> +#define MT8195_INFRA_RST0_RSV10			21
>> +#define MT8195_INFRA_RST0_RSV11			22
>> +#define MT8195_INFRA_RST0_RSV12			23
>> +#define MT8195_INFRA_RST0_RSV13			24
>> +#define MT8195_INFRA_RST0_RSV14			25
>> +#define MT8195_INFRA_RST0_RSV15			26
>> +#define MT8195_INFRA_RST0_RSV16			27
>> +#define MT8195_INFRA_RST0_RSV17			28
>> +#define MT8195_INFRA_RST0_RSV18			29
>> +#define MT8195_INFRA_RST0_RSV19			30
>> +#define MT8195_INFRA_RST0_RSV20			31
> 
> These are not proper IDs... don't work-around usage of bits with fake
> reserved IDs...

Hello Krzysztof,

Actually, I get that it may seem that Rex is trying to cheat with fake
reserved numbers... but it's really how the registers are laid out: there
really are reserved bits in between used reset bits.

I don't think that the reserved bits are doing anything though, so the
best way to proceed is to just remove them and map the dt-bindings IDs to
the HW register's bits in the driver instead.
Even though the current approach is very simplistic, I agree that this is
not how it's supposed to be done (and I'm sort-of sad about that).

Rex, please map these values in the reset driver so that, in this header,
you'll get something like:

#define MT8195_INFRA_RST0_THERM_CTRL_SWRST	0
#define MT8195_INFRA_RST0_DISP_PWM1_SWRST	1
#define MT8195_INFRA_RST0_MSDC3_SWRST		2
#define .... (etc)

Cheers,
Angelo

> 
> Best regards,
> Krzysztof