Re: [RFC v5.1 6/9] cache,soc: Move SiFive CCache driver & create drivers/cache

From: Conor Dooley <conor@kernel.org>
To: Ben Dooks <ben.dooks@codethink.co.uk>,
	arnd@arndb.de, palmer@dabbelt.com, prabhakar.csengg@gmail.com
Cc: Conor Dooley <conor.dooley@microchip.com>,
	ajones@ventanamicro.com, aou@eecs.berkeley.edu,
	apatel@ventanamicro.com, atishp@rivosinc.com,
	biju.das.jz@bp.renesas.com, devicetree@vger.kernel.org,
	geert@linux-m68k.org, guoren@kernel.org, hch@infradead.org,
	heiko@sntech.de, jszhang@kernel.org,
	krzysztof.kozlowski+dt@linaro.org, linux-kernel@vger.kernel.org,
	linux-renesas-soc@vger.kernel.org,
	linux-riscv@lists.infradead.org, magnus.damm@gmail.com,
	nathan@kernel.org, paul.walmsley@sifive.com,
	philipp.tomsich@vrull.eu,
	prabhakar.mahadev-lad.rj@bp.renesas.com, robh+dt@kernel.org,
	samuel@sholland.org, soc@kernel.org
Subject: Re: [RFC v5.1 6/9] cache,soc: Move SiFive CCache driver & create drivers/cache
Date: Wed, 04 Jan 2023 10:18:53 +0000	[thread overview]
Message-ID: <AA57B670-C952-47FE-9355-B4B1E4305CF6@kernel.org> (raw)
In-Reply-To: <49bd7b4a-b0e1-3213-8aed-9f39604f3935@codethink.co.uk>

On 4 January 2023 09:50:58 GMT, Ben Dooks <ben.dooks@codethink.co.uk> wrote:
>On 03/01/2023 21:03, Conor Dooley wrote:
>> From: Conor Dooley <conor.dooley@microchip.com>
>> 
>> The Zicbo* set of extensions for cache maintenance arrived too late &
>> several SoCs exist without them that require non-coherent DMA.
>> As things stand, the StarFive JH7100, Microchip PolarFire SoC & Renesas
>> RZ/Five all require cache maintenance and lack instructions for this
>> purpose.
>> Create a subsystem for cache drivers so that vendor specific behaviour
>> can be isolated from arch code, but keep the interfaces etc consistent.
>> Move the existing SiFive CCache driver to create drivers/cache.
>> 
>> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
>> ---
>>   MAINTAINERS                                   | 15 ++++++++-------
>>   drivers/Kconfig                               |  2 ++
>>   drivers/Makefile                              |  2 ++
>>   drivers/{soc/sifive => cache}/Kconfig         |  8 +++++++-
>>   drivers/{soc/sifive => cache}/Makefile        |  0
>>   drivers/{soc/sifive => cache}/sifive_ccache.c |  2 +-
>>   drivers/edac/sifive_edac.c                    |  2 +-
>>   drivers/soc/Kconfig                           |  1 -
>>   drivers/soc/Makefile                          |  1 -
>>   include/{soc/sifive => cache}/sifive_ccache.h |  0
>>   10 files changed, 21 insertions(+), 12 deletions(-)
>>   rename drivers/{soc/sifive => cache}/Kconfig (56%)
>>   rename drivers/{soc/sifive => cache}/Makefile (100%)
>>   rename drivers/{soc/sifive => cache}/sifive_ccache.c (99%)
>>   rename include/{soc/sifive => cache}/sifive_ccache.h (100%)
>> 
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index f61eb221415b..4437e96a657b 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -19054,13 +19054,6 @@ S:	Maintained
>>   F:	Documentation/devicetree/bindings/dma/sifive,fu540-c000-pdma.yaml
>>   F:	drivers/dma/sf-pdma/
>>   -SIFIVE SOC DRIVERS
>> -M:	Conor Dooley <conor@kernel.org>
>> -L:	linux-riscv@lists.infradead.org
>> -S:	Maintained
>> -T:	git https://git.kernel.org/pub/scm/linux/kernel/git/conor/linux.git/
>> -F:	drivers/soc/sifive/
>> -
>>   SILEAD TOUCHSCREEN DRIVER
>>   M:	Hans de Goede <hdegoede@redhat.com>
>>   L:	linux-input@vger.kernel.org
>> @@ -19873,6 +19866,14 @@ S:	Supported
>>   T:	git git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
>>   F:	drivers/staging/
>>   +STANDALONE CACHE CONTROLLER DRIVERS
>> +M:	Conor Dooley <conor@kernel.org>
>> +L:	linux-riscv@lists.infradead.org
>> +S:	Maintained
>> +T:	git https://git.kernel.org/pub/scm/linux/kernel/git/conor/linux.git/
>> +F:	drivers/cache
>> +F:	include/cache
>I thought the riscv list was subscribers only?

Shouldn't be. At least, I'm not one on this account and I don't get complaints!

>Maybe if we do the suggestion of other cache drivers here we should
>either use the main kernel one or find some arch non-specific list.

Yah, good point. I just moved the existing one, otherwise my script would yell at me about the maintainers pattern ;)

>
>> +
>>   STARFIRE/DURALAN NETWORK DRIVER
>>   M:	Ion Badulescu <ionut@badula.org>
>>   S:	Odd Fixes
>> diff --git a/drivers/Kconfig b/drivers/Kconfig
>> index 968bd0a6fd78..e592ba5276ae 100644
>> --- a/drivers/Kconfig
>> +++ b/drivers/Kconfig
>> @@ -241,4 +241,6 @@ source "drivers/peci/Kconfig"
>>     source "drivers/hte/Kconfig"
>>   +source "drivers/cache/Kconfig"
>> +
>>   endmenu
>> diff --git a/drivers/Makefile b/drivers/Makefile
>> index bdf1c66141c9..6ff60cf21823 100644
>> --- a/drivers/Makefile
>> +++ b/drivers/Makefile
>> @@ -38,6 +38,8 @@ obj-y				+= clk/
>>   # really early.
>>   obj-$(CONFIG_DMADEVICES)	+= dma/
>>   +obj-y				+= cache/
>> +
>>   # SOC specific infrastructure drivers.
>>   obj-y				+= soc/
>>   diff --git a/drivers/soc/sifive/Kconfig b/drivers/cache/Kconfig
>> similarity index 56%
>> rename from drivers/soc/sifive/Kconfig
>> rename to drivers/cache/Kconfig
>> index ed4c571f8771..bc852f005c10 100644
>> --- a/drivers/soc/sifive/Kconfig
>> +++ b/drivers/cache/Kconfig
>> @@ -1,9 +1,15 @@
>>   # SPDX-License-Identifier: GPL-2.0
>>   -if SOC_SIFIVE
>> +menuconfig CACHE_CONTROLLER
>> +	bool "Cache controller driver support"
>> +	default y if RISCV
>> +
>> +if CACHE_CONTROLLER
>>     config SIFIVE_CCACHE
>>   	bool "Sifive Composable Cache controller"
>> +	depends on RISCV
>> +	default y
>>   	help
>>   	  Support for the composable cache controller on SiFive platforms.
>>   
>
>Maybe we should find and move the ARM PL cache controllers and
>have them here too?

What to do there is up to Arnd et al :)
The maintainers entry would certainly have to look significantly different then.

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