Re: [PATCH 3/7] reset: add BCM6345 reset controller driver

Philipp Zabel
2020-06-09T16:32:12Z

Hi Álvaro,

On Tue, 2020-06-09 at 17:14 +0200, Álvaro Fernández Rojas wrote:
> Hi Philipp,
>
> > El 9 jun 2020, a las 17:06, Philipp Zabel <p.zabel@pengutronix.de> escribió:
> >
> > Hi Álvaro,
> >
> > On Tue, 2020-06-09 at 15:42 +0200, Álvaro Fernández Rojas wrote:
> > > Add support for resetting blocks through the Linux reset controller
> > > subsystem for BCM63xx SoCs.
> > >
> > > Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
> > > ---
> > > drivers/reset/Kconfig | 7 ++
> > > drivers/reset/Makefile | 1 +
> > > drivers/reset/reset-bcm6345.c | 149 ++++++++++++++++++++++++++++++++++
> > > 3 files changed, 157 insertions(+)
> > > create mode 100644 drivers/reset/reset-bcm6345.c
> > >
> > > diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
> > > index d9efbfd29646..9f1da978cef6 100644
> > > --- a/drivers/reset/Kconfig
> > > +++ b/drivers/reset/Kconfig
> > > @@ -41,6 +41,13 @@ config RESET_BERLIN
> > > help
> > > This enables the reset controller driver for Marvell Berlin SoCs.
> > >
> > > +config RESET_BCM6345
> > > + bool "BCM6345 Reset Controller"
> > > + depends on BMIPS_GENERIC || COMPILE_TEST
> > > + default BMIPS_GENERIC
> > > + help
> > > + This enables the reset controller driver for BCM6345 SoCs.
> > > +
> > > config RESET_BRCMSTB
> > > tristate "Broadcom STB reset controller"
> > > depends on ARCH_BRCMSTB || COMPILE_TEST
> > > diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
> > > index 249ed357c997..e642aae42f0f 100644
> > > --- a/drivers/reset/Makefile
> > > +++ b/drivers/reset/Makefile
> > > @@ -6,6 +6,7 @@ obj-$(CONFIG_ARCH_TEGRA) += tegra/
> > > obj-$(CONFIG_RESET_A10SR) += reset-a10sr.o
> > > obj-$(CONFIG_RESET_ATH79) += reset-ath79.o
> > > obj-$(CONFIG_RESET_AXS10X) += reset-axs10x.o
> > > +obj-$(CONFIG_RESET_BCM6345) += reset-bcm6345.o
> > > obj-$(CONFIG_RESET_BERLIN) += reset-berlin.o
> > > obj-$(CONFIG_RESET_BRCMSTB) += reset-brcmstb.o
> > > obj-$(CONFIG_RESET_BRCMSTB_RESCAL) += reset-brcmstb-rescal.o
> > > diff --git a/drivers/reset/reset-bcm6345.c b/drivers/reset/reset-bcm6345.c
> > > new file mode 100644
> > > index 000000000000..088b7fdb896b
> > > --- /dev/null
> > > +++ b/drivers/reset/reset-bcm6345.c
> > > @@ -0,0 +1,149 @@
> > > +// SPDX-License-Identifier: GPL-2.0-or-later
> > > +/*
> > > + * BCM6345 Reset Controller Driver
> > > + *
> > > + * Copyright (C) 2020 Álvaro Fernández Rojas <noltari@gmail.com>
> > > + */
> > > +
> > > +#include <linux/delay.h>
> > > +#include <linux/init.h>
> > > +#include <linux/io.h>
> > > +#include <linux/mod_devicetable.h>
> > > +#include <linux/platform_device.h>
> > > +#include <linux/reset-controller.h>
> > > +
> > > +#define BCM6345_RESET_NUM 32
> > > +#define BCM6345_RESET_SLEEP_MIN_US 10000
> > > +#define BCM6345_RESET_SLEEP_MAX_US 20000
> > > +
> > > +struct bcm6345_reset {
> > > + struct reset_controller_dev rcdev;
> > > + void __iomem *base;
> > > + spinlock_t lock;
> > > +};
> > > +
> > > +static int bcm6345_reset_update(struct bcm6345_reset *bcm6345_reset,
> > > + unsigned long id, bool assert)
> > > +{
> > > + uint32_t val;
> > > +
> > > + val = __raw_readl(bcm6345_reset->base);
> > > + if (assert)
> > > + val &= ~BIT(id);
> > > + else
> > > + val |= BIT(id);
> > > + __raw_writel(val, bcm6345_reset->base);
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static int bcm6345_reset_assert(struct reset_controller_dev *rcdev,
> > > + unsigned long id)
> > > +{
> > > + struct bcm6345_reset *bcm6345_reset =
> > > + container_of(rcdev, struct bcm6345_reset, rcdev);
> > > + unsigned long flags;
> > > +
> > > + spin_lock_irqsave(&bcm6345_reset->lock, flags);
> > > + bcm6345_reset_update(bcm6345_reset, id, true);
> > > + spin_unlock_irqrestore(&bcm6345_reset->lock, flags);
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static int bcm6345_reset_deassert(struct reset_controller_dev *rcdev,
> > > + unsigned long id)
> > > +{
> > > + struct bcm6345_reset *bcm6345_reset =
> > > + container_of(rcdev, struct bcm6345_reset, rcdev);
> > > + unsigned long flags;
> > > +
> > > + spin_lock_irqsave(&bcm6345_reset->lock, flags);
> > > + bcm6345_reset_update(bcm6345_reset, id, false);
> > > + spin_unlock_irqrestore(&bcm6345_reset->lock, flags);
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static int bcm6345_reset_reset(struct reset_controller_dev *rcdev,
> > > + unsigned long id)
> > > +{
> > > + struct bcm6345_reset *bcm6345_reset =
> > > + container_of(rcdev, struct bcm6345_reset, rcdev);
> > > + unsigned long flags;
> > > +
> > > + spin_lock_irqsave(&bcm6345_reset->lock, flags);
> > > + usleep_range(BCM6345_RESET_SLEEP_MIN_US,
> > > + BCM6345_RESET_SLEEP_MAX_US);
> >
> > What is the purpose of sleeping before reset assertion?
>
> None, I must have introduced that for testing something and then I forgot to remove it. Sorry for that...
>
> > If you can do without this, with I think this driver could be made to
> > use reset-simple.
>
> Yes, but only if I can add reset support with a configurable sleep range to reset-simple. Is this possible?

I should have mentioned, support for this is on the reset/next branch:

git://git.pengutronix.de/pza/linux.git reset/next

regards
Philipp