Re: [PATCH] reset: Add Tegra BPMP reset driver

[Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

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On Tue, Nov 15, 2016 at 06:11:16PM +0100, Philipp Zabel wrote:
> Hi Thierry,
> 
> Am Dienstag, den 15.11.2016, 17:17 +0100 schrieb Thierry Reding:
> > From: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> > 
> > This driver uses the services provided by the BPMP firmware driver to
> > implement a reset driver based on the MRQ_RESET request.
> > 
> > Signed-off-by: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> > ---
> > Hi Philipp,
> > 
> > I'm looking for an Acked-by on this because there are complicated
> > dependencies between this and other branches in the Tegra tree, so I
> > think it would be easiest to merge through that.
> > 
> > Thanks,
> > Thierry
> > 
> >  drivers/reset/Kconfig            |  1 +
> >  drivers/reset/Makefile           |  1 +
> >  drivers/reset/tegra/Kconfig      |  3 ++
> >  drivers/reset/tegra/Makefile     |  1 +
> >  drivers/reset/tegra/reset-bpmp.c | 71 ++++++++++++++++++++++++++++++++++++++++
> >  5 files changed, 77 insertions(+)
> >  create mode 100644 drivers/reset/tegra/Kconfig
> >  create mode 100644 drivers/reset/tegra/Makefile
> >  create mode 100644 drivers/reset/tegra/reset-bpmp.c
> > 
> > diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
> > index 06d9fa2f3bc0..172dc966a01f 100644
> > --- a/drivers/reset/Kconfig
> > +++ b/drivers/reset/Kconfig
> > @@ -94,5 +94,6 @@ config RESET_ZYNQ
> >  
> >  source "drivers/reset/sti/Kconfig"
> >  source "drivers/reset/hisilicon/Kconfig"
> > +source "drivers/reset/tegra/Kconfig"
> >  
> >  endif
> > diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
> > index bbe7026617fc..13b346e03d84 100644
> > --- a/drivers/reset/Makefile
> > +++ b/drivers/reset/Makefile
> > @@ -1,6 +1,7 @@
> >  obj-y += core.o
> >  obj-y += hisilicon/
> >  obj-$(CONFIG_ARCH_STI) += sti/
> > +obj-$(CONFIG_ARCH_TEGRA) += tegra/
> 
> Could drivers therein be compiled without ARCH_TEGRA enabled? If so,
> please use obj-y here.
> 
> >  obj-$(CONFIG_RESET_ATH79) += reset-ath79.o
> >  obj-$(CONFIG_RESET_BERLIN) += reset-berlin.o
> >  obj-$(CONFIG_RESET_LPC18XX) += reset-lpc18xx.o
> > diff --git a/drivers/reset/tegra/Kconfig b/drivers/reset/tegra/Kconfig
> > new file mode 100644
> > index 000000000000..0ec57a7016e6
> > --- /dev/null
> > +++ b/drivers/reset/tegra/Kconfig
> > @@ -0,0 +1,3 @@
> > +config RESET_TEGRA_BPMP
> > +	def_bool y
> > +	depends on TEGRA_BPMP
> 
> Or probably not, it looks like TEGRA_BPMP depends on ARCH_TEGRA and
> doesn't provide any stubs. I think this could be just
> 	def_bool TEGRA_BPMP
> though. But see below, RESET_TEGRA_BPMP doesn't seem to be used at all.

Yes, this is all really Tegra-specific, so I don't think it makes sense
to allow building this without.

> > diff --git a/drivers/reset/tegra/Makefile b/drivers/reset/tegra/Makefile
> > new file mode 100644
> > index 000000000000..fd943b1ae029
> > --- /dev/null
> > +++ b/drivers/reset/tegra/Makefile
> > @@ -0,0 +1 @@
> > +obj-$(CONFIG_ARCH_TEGRA_186_SOC)	+= reset-bpmp.o
> 
> This should probably be obj-$(CONFIG_RESET_TEGRA_BPMP).

Yes indeed. I had introduced RESET_TEGRA_BPMP is a way of resolving the
dependencies more nicely. The code structure is such that the BPMP
driver needs to call clock and reset drivers, and there are
CLOCK_TEGRA_BPMP and RESET_TEGRA_BPMP symbols to protect those bits of
the code and avoid a circular dependency.

> > diff --git a/drivers/reset/tegra/reset-bpmp.c b/drivers/reset/tegra/reset-bpmp.c
> > new file mode 100644
> > index 000000000000..5daf2ee1a396
> > --- /dev/null
> > +++ b/drivers/reset/tegra/reset-bpmp.c
> > @@ -0,0 +1,71 @@
> > +/*
> > + * Copyright (C) 2016 NVIDIA Corporation
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +
> > +#include <linux/reset-controller.h>
> > +
> > +#include <soc/tegra/bpmp.h>
> > +#include <soc/tegra/bpmp-abi.h>
> > +
> > +static struct tegra_bpmp *to_tegra_bpmp(struct reset_controller_dev *rstc)
> > +{
> > +	return container_of(rstc, struct tegra_bpmp, rstc);
> > +}
> > +
> > +static int tegra_bpmp_reset_common(struct reset_controller_dev *rstc,
> > +				   enum mrq_reset_commands command,
> > +				   unsigned int id)
> > +{
> > +	struct tegra_bpmp *bpmp = to_tegra_bpmp(rstc);
> > +	struct mrq_reset_request request;
> > +	struct tegra_bpmp_message msg;
> > +
> > +	memset(&request, 0, sizeof(request));
> > +	request.cmd = command;
> > +	request.reset_id = id;
> > +
> > +	memset(&msg, 0, sizeof(msg));
> > +	msg.mrq = MRQ_RESET;
> > +	msg.tx.data = &request;
> > +	msg.tx.size = sizeof(request);
> > +
> > +	return tegra_bpmp_transfer(bpmp, &msg);
> > +}
> > +
> > +static int tegra_bpmp_reset_module(struct reset_controller_dev *rstc,
> > +				   unsigned long id)
> > +{
> > +	return tegra_bpmp_reset_common(rstc, CMD_RESET_MODULE, id);
> > +}
> > +
> > +static int tegra_bpmp_reset_assert(struct reset_controller_dev *rstc,
> > +				   unsigned long id)
> > +{
> > +	return tegra_bpmp_reset_common(rstc, CMD_RESET_ASSERT, id);
> > +}
> > +
> > +static int tegra_bpmp_reset_deassert(struct reset_controller_dev *rstc,
> > +				     unsigned long id)
> > +{
> > +	return tegra_bpmp_reset_common(rstc, CMD_RESET_DEASSERT, id);
> > +}
> > +
> > +static const struct reset_control_ops tegra_bpmp_reset_ops = {
> > +	.reset = tegra_bpmp_reset_module,
> > +	.assert = tegra_bpmp_reset_assert,
> > +	.deassert = tegra_bpmp_reset_deassert,
> > +};
> > +
> > +int tegra_bpmp_init_resets(struct tegra_bpmp *bpmp)
> > +{
> > +	bpmp->rstc.ops = &tegra_bpmp_reset_ops;
> > +	bpmp->rstc.owner = THIS_MODULE;
> > +	bpmp->rstc.of_node = bpmp->dev->of_node;
> > +	bpmp->rstc.nr_resets = bpmp->soc->num_resets;
> > +
> > +	return devm_reset_controller_register(bpmp->dev, &bpmp->rstc);
> > +}
> 
> With the Kconfig symbol confusion resolved,
> 
> Acked-by: Philipp Zabel <p.zabel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> 
> to merge this via the Tegra trees.

Great, I'll make that change and merge through the Tegra tree.

Thanks!
Thierry

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