Re: [PATCH v4 2/4] drivers: misc: Add Support for TMR Manager

From: Greg KH <gregkh@linuxfoundation.org>
To: Appana Durga Kedareswara rao <appana.durga.kedareswara.rao@amd.com>
Cc: appanad@amd.com, robh+dt@kernel.org,
	krzysztof.kozlowski+dt@linaro.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, michal.simek@xilinx.com,
	derek.kiernan@xilinx.com, dragan.cvetic@xilinx.com,
	arnd@arndb.de, linux-arm-kernel@lists.infradead.org, git@amd.com
Subject: Re: [PATCH v4 2/4] drivers: misc: Add Support for TMR Manager
Date: Fri, 9 Sep 2022 10:40:14 +0200	[thread overview]
Message-ID: <Yxr77l3UGbphuJkM@kroah.com> (raw)
In-Reply-To: <20220909061916.2935431-3-appana.durga.kedareswara.rao@amd.com>

On Fri, Sep 09, 2022 at 11:49:14AM +0530, Appana Durga Kedareswara rao wrote:
> Triple Modular Redundancy(TMR) subsystem contains three microblaze cores,
> subsystem is fault-tolerant and continues to operate nominally after
> encountering an error. Together with the capability to detect and recover
> from errors, the implementation ensures the reliability of the entire
> subsystem.  TMR Manager is responsible for performing recovery of the
> subsystem detects the fault via a break signal it invokes microblaze
> software break handler which calls the tmr manager driver api to
> update the error count and status, added support for fault detection
> feature via sysfs interface.
> 
> Usage:
> To know the break handler count(Error count):
> cat /sys/devices/platform/amba_pl/44a10000.tmr_manager/errcnt
> 
> Signed-off-by: Appana Durga Kedareswara rao <appana.durga.kedareswara.rao@amd.com>
> ---
> Changes for v4:
> --> None.
> Changes for v3:
> --> Corrected month in the sysfs-driver-xilinx-tmr-manager file
> --> Updated the Kconfig to compile the driver as a module
> --> Removed unneeded status sysfs attribute
> Changes for v2:
> --> Fixed Month in the sysfs description.
> --> Fixed line over 80 char in driver.
> --> Replaced kstrtol with kstrtoul as suggested by Michal.
> --> Added error check for xlnx,magic1 value.
> 
>  .../testing/sysfs-driver-xilinx-tmr-manager   |  16 ++
>  MAINTAINERS                                   |   7 +
>  drivers/misc/Kconfig                          |  10 +
>  drivers/misc/Makefile                         |   3 +-
>  drivers/misc/xilinx_tmr_manager.c             | 222 ++++++++++++++++++
>  5 files changed, 257 insertions(+), 1 deletion(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-driver-xilinx-tmr-manager
>  create mode 100644 drivers/misc/xilinx_tmr_manager.c
> 
> diff --git a/Documentation/ABI/testing/sysfs-driver-xilinx-tmr-manager b/Documentation/ABI/testing/sysfs-driver-xilinx-tmr-manager
> new file mode 100644
> index 000000000000..2a97be6ae849
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-driver-xilinx-tmr-manager
> @@ -0,0 +1,16 @@
> +What:		/sys/devices/platform/amba_pl/<dev>/errcnt
> +Date:		Sep 2022
> +Contact:	appana.durga.kedareswara.rao@amd.com
> +Description:	This control file provides the fault detection count.
> +		This file cannot be written.
> +		Example:
> +		# cat /sys/devices/platform/amba_pl/44a10000.tmr_manager/errcnt
> +		  1
> +
> +What:		/sys/devices/platform/amba_pl/<dev>/dis_block_break
> +Date:		Sep 2022
> +Contact:	appana.durga.kedareswara.rao@amd.com
> +Description:	Write any value to it, This control file enables the break signal.
> +		This file is write only.
> +		Example:
> +		# echo <any value> > /sys/devices/platform/amba_pl/44a10000.tmr_manager/dis_block_break
> diff --git a/MAINTAINERS b/MAINTAINERS
> index f1390b8270b2..5fc5ec13985e 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -13277,6 +13277,13 @@ W:	http://www.monstr.eu/fdt/
>  T:	git git://git.monstr.eu/linux-2.6-microblaze.git
>  F:	arch/microblaze/
>  
> +MICROBLAZE TMR MANAGER
> +M:	Appana Durga Kedareswara rao <appana.durga.kedareswara.rao@amd.com>
> +S:	Supported
> +F:	Documentation/ABI/testing/sysfs-driver-xilinx-tmr-manager
> +F:	Documentation/devicetree/bindings/misc/xlnx,tmr-manager.yaml
> +F:	drivers/misc/xilinx_tmr_manager.c
> +
>  MICROCHIP AT91 DMA DRIVERS
>  M:	Ludovic Desroches <ludovic.desroches@microchip.com>
>  M:	Tudor Ambarus <tudor.ambarus@microchip.com>
> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> index 94e9fb4cdd76..1508cc29b05a 100644
> --- a/drivers/misc/Kconfig
> +++ b/drivers/misc/Kconfig
> @@ -496,6 +496,16 @@ config VCPU_STALL_DETECTOR
>  
>  	  If you do not intend to run this kernel as a guest, say N.
>  
> +config TMR_MANAGER
> +	tristate "Select TMR Manager"
> +	depends on MICROBLAZE && MB_MANAGER
> +	help
> +	  This option enables the driver developed for TMR Manager. The Triple
> +	  Modular Redundancy(TMR) manager provides support for fault detection
> +	  via sysfs interface.

What is the module name?

And the fault detection api is in debugfs, not sysfs, right?

thanks,

greg k-h

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