linux-kernel - Re: [PATCH 2/2] soc: ti: pruss: add support for AM18XX/OMAP-L138 PRUSS

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Message-ID: <2ae31c89-fe5c-bc80-f7cc-a24f55616d9a@lechnology.com>
Date:   Sat, 16 Jan 2021 14:15:38 -0600
From:   David Lechner <david@...hnology.com>
To:     Suman Anna <s-anna@...com>, linux-arm-kernel@...ts.infradead.org
Cc:     Rob Herring <robh+dt@...nel.org>,
        Santosh Shilimkar <ssantosh@...nel.org>,
        Grzegorz Jaszczyk <grzegorz.jaszczyk@...aro.org>,
        Sekhar Nori <nsekhar@...com>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] soc: ti: pruss: add support for AM18XX/OMAP-L138
 PRUSS

On 1/15/21 6:52 PM, Suman Anna wrote:
> Hi David,
> 
> On 1/4/21 12:30 PM, David Lechner wrote:
>> This adds support for the PRUSS found in AM18XX/OMAP-L138. This PRUSS
>> doesn't have a CFG register, so that is made optional as selected by
>> the device tree compatible string.
>>
>> ARCH_DAVINCI is added in the Kconfig so that the driver can be selected
>> on that platform.
>>
>> Signed-off-by: David Lechner <david@...hnology.com>
>> ---
>>   drivers/soc/ti/Kconfig |  2 +-
>>   drivers/soc/ti/pruss.c | 76 ++++++++++++++++++++++++------------------
>>   2 files changed, 45 insertions(+), 33 deletions(-)
>>
>> diff --git a/drivers/soc/ti/Kconfig b/drivers/soc/ti/Kconfig
>> index 7e2fb1c16af1..7a692a21480a 100644
>> --- a/drivers/soc/ti/Kconfig
>> +++ b/drivers/soc/ti/Kconfig
>> @@ -85,7 +85,7 @@ config TI_K3_SOCINFO
>>   
>>   config TI_PRUSS
>>   	tristate "TI PRU-ICSS Subsystem Platform drivers"
>> -	depends on SOC_AM33XX || SOC_AM43XX || SOC_DRA7XX || ARCH_KEYSTONE || ARCH_K3
>> +	depends on ARCH_DAVINCI || SOC_AM33XX || SOC_AM43XX || SOC_DRA7XX || ARCH_KEYSTONE || ARCH_K3
>>   	select MFD_SYSCON
>>   	help
>>   	  TI PRU-ICSS Subsystem platform specific support.
>> diff --git a/drivers/soc/ti/pruss.c b/drivers/soc/ti/pruss.c
>> index 5d6e7132a5c4..bfaf3ff74b01 100644
>> --- a/drivers/soc/ti/pruss.c
>> +++ b/drivers/soc/ti/pruss.c
>> @@ -24,10 +24,12 @@
>>    * struct pruss_private_data - PRUSS driver private data
>>    * @has_no_sharedram: flag to indicate the absence of PRUSS Shared Data RAM
>>    * @has_core_mux_clock: flag to indicate the presence of PRUSS core clock
>> + * @has_cfg: flag to indicate the presence of PRUSS CFG registers
> 
> I recommend to change this to a negative flag as the Davinci platforms are the
> only ones that don't have CFG (being the very first SoCs with a PRUSS IP)
> sub-module.

Negative flags hurt my brain. :-)

I was actually thinking about submitting a patch to convert
has_no_sharedram to a positive flag as well. But I understand
the sentiment of only setting the flag true for the odd case
rather than the usual case.

> 
>>    */
>>   struct pruss_private_data {
>>   	bool has_no_sharedram;
>>   	bool has_core_mux_clock;
>> +	bool has_cfg;
>>   };
>>   
>>   static void pruss_of_free_clk_provider(void *data)
>> @@ -239,42 +241,44 @@ static int pruss_probe(struct platform_device *pdev)
>>   		goto rpm_disable;
>>   	}
>>   
> 
> And use it here to skip all the cfg code parsing. All the below delta is just
> for the additional indentation for the flag. If you don't like goto's in
> non-error paths, then we can refactor the CFG parse code into a separate function.
> 

Refactoring to a separate function sounds good to me.