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

Philipp Zabel
2020-06-09T15:06:52Z

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?

If you can do without this, with I think this driver could be made to
use reset-simple.

regards
Philipp