Re: [PATCH v2 5/5] reset: Add support for resets provided by SCMI

[Sudeep Holla]

On Wed, Aug 07, 2019 at 10:04:26AM +0200, Philipp Zabel wrote:
> On Tue, 2019-08-06 at 18:02 +0100, Sudeep Holla wrote:
> > On some ARM based systems, a separate Cortex-M based System Control
> > Processor(SCP) provides the overall power, clock, reset and system
> > control. System Control and Management Interface(SCMI) Message Protocol
> > is defined for the communication between the Application Cores(AP)
> > and the SCP.
> >
> > Adds support for the resets provided using SCMI protocol for performing
> > reset management of various devices present on the SoC. Various reset
> > functionalities are achieved by the means of different ARM SCMI device
> > operations provided by the ARM SCMI framework.
> >
> > Cc: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
> > Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
> > ---
> >  MAINTAINERS                |   1 +
> >  drivers/reset/Kconfig      |  11 ++++
> >  drivers/reset/Makefile     |   1 +
> >  drivers/reset/reset-scmi.c | 126 +++++++++++++++++++++++++++++++++++++
> >  4 files changed, 139 insertions(+)
> >  create mode 100644 drivers/reset/reset-scmi.c
> >
> > v1->v2:
> > 	- Renamed RESET_ARM_SCMI to RESET_SCMI and reworded Kconfig text
> > 	- Dropped unused struct device pointer from scmi_reset_data
> > 	- Added to_scmi_handle which helped to remove some repetitive code
> > 	- Fixed some doxygen comments
> > 	- Initialised rcdev.nr_resets
> > 	- Fixed MODULE_DESCRIPTION
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 6426db5198f0..f4af5c59c116 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -15545,6 +15545,7 @@ F:	drivers/clk/clk-sc[mp]i.c
> >  F:	drivers/cpufreq/sc[mp]i-cpufreq.c
> >  F:	drivers/firmware/arm_scpi.c
> >  F:	drivers/firmware/arm_scmi/
> > +F:	drivers/reset/reset-scmi.c
> >  F:	include/linux/sc[mp]i_protocol.h
> >
> >  SYSTEM RESET/SHUTDOWN DRIVERS
> > diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
> > index 21efb7d39d62..4178ac11ba85 100644
> > --- a/drivers/reset/Kconfig
> > +++ b/drivers/reset/Kconfig
> > @@ -116,6 +116,17 @@ config RESET_QCOM_PDC
> >  	  to control reset signals provided by PDC for Modem, Compute,
> >  	  Display, GPU, Debug, AOP, Sensors, Audio, SP and APPS.
> >
> > +config RESET_SCMI
> > +	tristate "Reset driver controlled via ARM SCMI interface"
> > +	depends on ARM_SCMI_PROTOCOL || COMPILE_TEST
> > +	default ARM_SCMI_PROTOCOL
> > +	help
> > +	  This driver provides support for reset signal/domains that are
> > +	  controlled by firmware that implements the SCMI interface.
> > +
> > +	  This driver uses SCMI Message Protocol to interact with the
> > +	  firmware controlling all the reset signals.
> > +
> >  config RESET_SIMPLE
> >  	bool "Simple Reset Controller Driver" if COMPILE_TEST
> >  	default ARCH_STM32 || ARCH_STRATIX10 || ARCH_SUNXI || ARCH_ZX || ARCH_ASPEED || ARCH_BITMAIN
> > diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
> > index 61456b8f659c..cf60ce526064 100644
> > --- a/drivers/reset/Makefile
> > +++ b/drivers/reset/Makefile
> > @@ -18,6 +18,7 @@ obj-$(CONFIG_RESET_OXNAS) += reset-oxnas.o
> >  obj-$(CONFIG_RESET_PISTACHIO) += reset-pistachio.o
> >  obj-$(CONFIG_RESET_QCOM_AOSS) += reset-qcom-aoss.o
> >  obj-$(CONFIG_RESET_QCOM_PDC) += reset-qcom-pdc.o
> > +obj-$(CONFIG_RESET_SCMI) += reset-scmi.o
> >  obj-$(CONFIG_RESET_SIMPLE) += reset-simple.o
> >  obj-$(CONFIG_RESET_STM32MP157) += reset-stm32mp1.o
> >  obj-$(CONFIG_RESET_SOCFPGA) += reset-socfpga.o
> > diff --git a/drivers/reset/reset-scmi.c b/drivers/reset/reset-scmi.c
> > new file mode 100644
> > index 000000000000..5e976a02a6cc
> > --- /dev/null
> > +++ b/drivers/reset/reset-scmi.c
> > @@ -0,0 +1,126 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * ARM System Control and Management Interface (ARM SCMI) reset driver
> > + *
> > + * Copyright (C) 2019 ARM Ltd.
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/mutex.h>
>
> You can drop mutex.h, it is unused.
>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
>
> This is not a platform device driver. Better replace this with
>
> #include <linux/device.h>
>
> > +#include <linux/reset-controller.h>
> > +#include <linux/scmi_protocol.h>
> > +
> > +/**
> > + * struct scmi_reset_data - reset controller information structure
> > + * @rcdev: reset controller entity
> > + * @handle: ARM SCMI handle used for communication with system controller
> > + * @dev: reset controller device pointer
>
> Drop this line, dev has been removed from struct scmi_reset_data.
>

All the above 3 are now fixed.

> > + */
> > +struct scmi_reset_data {
> > +	struct reset_controller_dev rcdev;
> > +	const struct scmi_handle *handle;
> > +};
> > +
> > +#define to_scmi_reset_data(p)	container_of((p), struct scmi_reset_data, rcdev)
> > +#define to_scmi_handle(p)	(to_scmi_reset_data(p)->handle)
> [...]
>
> Apart from these,
> Reviewed-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
>

Thanks

--
Regards,
Sudeep