Re: [RFC PATCH v4 2/5] irqchip: Add RZ/G2L IA55 Interrupt Controller driver

Marc Zyngier
2022-03-17T16:13:59Z

On Thu, 17 Mar 2022 01:24:01 +0000,
Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> wrote:
>
> Add a driver for the Renesas RZ/G2L Interrupt Controller.
>
> This supports external pins being used as interrupts. It supports
> one line for NMI, 8 external pins and 32 GPIO pins (out of 123)
> to be used as IRQ lines.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> ---
> drivers/irqchip/Kconfig | 8 +
> drivers/irqchip/Makefile | 1 +
> drivers/irqchip/irq-renesas-rzg2l.c | 462 ++++++++++++++++++++++++++++
> 3 files changed, 471 insertions(+)
> create mode 100644 drivers/irqchip/irq-renesas-rzg2l.c
>
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index 7038957f4a77..afc5999f4955 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -242,6 +242,14 @@ config RENESAS_RZA1_IRQC
> Enable support for the Renesas RZ/A1 Interrupt Controller, to use up
> to 8 external interrupts with configurable sense select.
>
> +config RENESAS_RZG2L_IRQC
> + bool "Renesas RZ/G2L (and alike SoC) IRQC support" if COMPILE_TEST
> + select GENERIC_IRQ_CHIP
> + select IRQ_DOMAIN_HIERARCHY
> + help
> + Enable support for the Renesas RZ/G2L (and alike SoC) Interrupt Controller
> + for external devices.
> +
> config SL28CPLD_INTC
> bool "Kontron sl28cpld IRQ controller"
> depends on MFD_SL28CPLD=y || COMPILE_TEST
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> index c1f611cbfbf8..b536e514a7c9 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -51,6 +51,7 @@ obj-$(CONFIG_RDA_INTC) += irq-rda-intc.o
> obj-$(CONFIG_RENESAS_INTC_IRQPIN) += irq-renesas-intc-irqpin.o
> obj-$(CONFIG_RENESAS_IRQC) += irq-renesas-irqc.o
> obj-$(CONFIG_RENESAS_RZA1_IRQC) += irq-renesas-rza1.o
> +obj-$(CONFIG_RENESAS_RZG2L_IRQC) += irq-renesas-rzg2l.o
> obj-$(CONFIG_VERSATILE_FPGA_IRQ) += irq-versatile-fpga.o
> obj-$(CONFIG_ARCH_NSPIRE) += irq-zevio.o
> obj-$(CONFIG_ARCH_VT8500) += irq-vt8500.o
> diff --git a/drivers/irqchip/irq-renesas-rzg2l.c b/drivers/irqchip/irq-renesas-rzg2l.c
> new file mode 100644
> index 000000000000..be9741e88bd7
> --- /dev/null
> +++ b/drivers/irqchip/irq-renesas-rzg2l.c
> @@ -0,0 +1,462 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Renesas RZ/G2L IRQC Driver
> + *
> + * Copyright (C) 2022 Renesas Electronics Corporation.
> + *
> + * Author: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/irqchip.h>
> +#include <linux/irqdomain.h>
> +#include <linux/of_address.h>
> +#include <linux/reset.h>
> +#include <linux/spinlock.h>
> +
> +#define IRQC_IRQ_START 1
> +#define IRQC_IRQ_COUNT 8
> +#define IRQC_TINT_START 9
> +#define IRQC_TINT_COUNT 32
> +#define IRQC_NUM_IRQ 41
> +
> +#define ISCR 0x10
> +#define IITSR 0x14
> +#define TSCR 0x20
> +#define TITSR0 0x24
> +#define TITSR1 0x28
> +#define TITSR0_MAX_INT 16
> +#define TITSEL_WIDTH 0x2
> +#define TSSR(n) (0x30 + ((n) * 4))
> +#define TIEN BIT(7)
> +#define TSSEL_SHIFT(n) (8 * (n))
> +#define TSSEL_MASK GENMASK(7, 0)
> +#define IRQ_MASK 0x3
> +
> +#define TSSR_OFFSET(n) ((n) % 4)
> +#define TSSR_INDEX(n) ((n) / 4)
> +
> +#define TITSR_TITSEL_EDGE_RISING 0
> +#define TITSR_TITSEL_EDGE_FALLING 1
> +#define TITSR_TITSEL_LEVEL_HIGH 2
> +#define TITSR_TITSEL_LEVEL_LOW 3
> +
> +#define IITSR_IITSEL(n, sense) ((sense) << ((n) * 2))
> +#define IITSR_IITSEL_LEVEL_LOW 0
> +#define IITSR_IITSEL_EDGE_FALLING 1
> +#define IITSR_IITSEL_EDGE_RISING 2
> +#define IITSR_IITSEL_EDGE_BOTH 3
> +#define IITSR_IITSEL_MASK(n) IITSR_IITSEL((n), 3)
> +
> +#define TINT_EXTRACT_HWIRQ(x) ((x) & ~GENMASK(31, 16))
> +#define TINT_EXTRACT_GPIOINT(x) ((x) >> 16)
> +
> +struct rzg2l_irqc_priv {
> + void __iomem *base;
> + struct of_phandle_args map[IRQC_NUM_IRQ];
> + raw_spinlock_t lock;
> +};
> +
> +struct rzg2l_irqc_chip_data {
> + int tint;
> +};
> +
> +static struct rzg2l_irqc_priv *irq_data_to_priv(struct irq_data *data)
> +{
> + return data->domain->host_data;
> +}
> +
> +static void rzg2l_irq_eoi(struct irq_data *d)
> +{
> + struct rzg2l_irqc_priv *priv = irq_data_to_priv(d);
> + unsigned int hw_irq = irqd_to_hwirq(d) - IRQC_IRQ_START;
> + u16 bit = BIT(hw_irq);
> + unsigned long flags;
> + u32 reg;
> +
> + raw_spin_lock_irqsave(&priv->lock, flags);

Why the irqsave flavour? Is there any case where EOI isn't performed
in a context that has interrupts already disabled?

> + reg = readl_relaxed(priv->base + ISCR);
> + if (reg & bit)
> + writel_relaxed(GENMASK(IRQC_IRQ_COUNT - 1, 0) & ~bit,
> + priv->base + ISCR);
> + raw_spin_unlock_irqrestore(&priv->lock, flags);
> + irq_chip_eoi_parent(d);
> +}
> +
> +static void rzg2l_tint_eoi(struct irq_data *d)
> +{
> + struct rzg2l_irqc_priv *priv = irq_data_to_priv(d);
> + unsigned int hw_irq = irqd_to_hwirq(d);
> + u32 bit = BIT(hw_irq - IRQC_TINT_START);
> + unsigned long flags;
> + u32 reg;
> +
> + raw_spin_lock_irqsave(&priv->lock, flags);
> + reg = readl_relaxed(priv->base + TSCR);
> + if (reg & bit)
> + writel_relaxed(GENMASK(IRQC_TINT_COUNT - 1, 0) & ~bit,
> + priv->base + TSCR);
> + raw_spin_unlock_irqrestore(&priv->lock, flags);
> + irq_chip_eoi_parent(d);
> +}
> +
> +static void rzg2l_irqc_eoi(struct irq_data *d)
> +{
> + unsigned int hw_irq = irqd_to_hwirq(d);
> +
> + if (hw_irq >= IRQC_IRQ_START && hw_irq <= IRQC_IRQ_COUNT)
> + return rzg2l_irq_eoi(d);

return function_returning_void()? No, please.

> + else if (hw_irq >= IRQC_TINT_START && hw_irq <= IRQC_TINT_COUNT)
> + return rzg2l_tint_eoi(d);

Move the locking and the call to irq_chip_eoi_parent() here, as there
is no need to duplicate any of this.

> +}
> +
> +static void rzg2l_irqc_irq_disable(struct irq_data *d)
> +{
> + unsigned int hw_irq = irqd_to_hwirq(d);
> +
> + if (hw_irq >= IRQC_TINT_START && hw_irq <= IRQC_TINT_COUNT) {
> + struct rzg2l_irqc_priv *priv = irq_data_to_priv(d);
> + u32 offset = hw_irq - IRQC_TINT_START;
> + u32 tssr_offset = TSSR_OFFSET(offset);
> + u8 tssr_index = TSSR_INDEX(offset);
> + unsigned long flags;
> + u32 reg;
> +
> + raw_spin_lock_irqsave(&priv->lock, flags);
> + reg = readl_relaxed(priv->base + TSSR(tssr_index));
> + reg &= ~(TSSEL_MASK << tssr_offset);
> + writel_relaxed(reg, priv->base + TSSR(tssr_index));
> + raw_spin_unlock_irqrestore(&priv->lock, flags);
> + }
> + irq_chip_disable_parent(d);
> +}
> +
> +static void rzg2l_irqc_irq_enable(struct irq_data *d)
> +{
> + unsigned int hw_irq = irqd_to_hwirq(d);
> +
> + if (hw_irq >= IRQC_TINT_START && hw_irq <= IRQC_TINT_COUNT) {
> + struct rzg2l_irqc_priv *priv = irq_data_to_priv(d);
> + struct rzg2l_irqc_chip_data *chip_data = d->chip_data;
> + u32 offset = hw_irq - IRQC_TINT_START;
> + u32 tssr_offset = TSSR_OFFSET(offset);
> + u8 tssr_index = TSSR_INDEX(offset);
> + unsigned long flags;
> + u32 reg;
> +
> + raw_spin_lock_irqsave(&priv->lock, flags);
> + reg = readl_relaxed(priv->base + TSSR(tssr_index));
> + reg |= (TIEN | chip_data->tint) << TSSEL_SHIFT(tssr_offset);
> + writel_relaxed(reg, priv->base + TSSR(tssr_index));
> + raw_spin_unlock_irqrestore(&priv->lock, flags);
> + }
> + irq_chip_enable_parent(d);
> +}
> +
> +static int rzg2l_irq_set_type(struct irq_data *d, unsigned int type)
> +{
> + unsigned int hw_irq = irqd_to_hwirq(d) - IRQC_IRQ_START;
> + struct rzg2l_irqc_priv *priv = irq_data_to_priv(d);
> + unsigned long flags;
> + u16 sense, tmp;
> +
> + switch (type & IRQ_TYPE_SENSE_MASK) {
> + case IRQ_TYPE_LEVEL_LOW:
> + sense = IITSR_IITSEL_LEVEL_LOW;
> + break;
> +
> + case IRQ_TYPE_EDGE_FALLING:
> + sense = IITSR_IITSEL_EDGE_FALLING;
> + break;
> +
> + case IRQ_TYPE_EDGE_RISING:
> + sense = IITSR_IITSEL_EDGE_RISING;
> + break;
> +
> + case IRQ_TYPE_EDGE_BOTH:
> + sense = IITSR_IITSEL_EDGE_BOTH;
> + break;
> +
> + default:
> + return -EINVAL;
> + }
> +
> + raw_spin_lock_irqsave(&priv->lock, flags);

This already happens in an irq disabled context.

> + tmp = readl_relaxed(priv->base + IITSR);
> + tmp &= ~IITSR_IITSEL_MASK(hw_irq);
> + tmp |= IITSR_IITSEL(hw_irq, sense);
> + writel_relaxed(tmp, priv->base + IITSR);
> + raw_spin_unlock_irqrestore(&priv->lock, flags);

What about the parent irqchip? If this is a hierarchical setup, it
definitely should be told.

> +
> + return 0;
> +}
> +
> +static int rzg2l_tint_set_edge(struct irq_data *d, unsigned int type)
> +{
> + struct rzg2l_irqc_priv *priv = irq_data_to_priv(d);
> + unsigned int hwirq = irqd_to_hwirq(d);
> + u32 titseln = hwirq - IRQC_TINT_START;
> + unsigned long flags;
> + u32 offset;
> + u8 sense;
> + u32 reg;
> +
> + switch (type & IRQ_TYPE_SENSE_MASK) {
> + case IRQ_TYPE_EDGE_RISING:
> + sense = TITSR_TITSEL_EDGE_RISING;
> + break;
> +
> + case IRQ_TYPE_EDGE_FALLING:
> + sense = TITSR_TITSEL_EDGE_FALLING;
> + break;
> +
> + default:
> + return -EINVAL;
> + }
> +
> + if (titseln < TITSR0_MAX_INT) {
> + offset = TITSR0;
> + } else {
> + titseln /= TITSEL_WIDTH;
> + offset = TITSR1;
> + }
> +
> + raw_spin_lock_irqsave(&priv->lock, flags);
> + reg = readl_relaxed(priv->base + offset);
> + reg &= ~(IRQ_MASK << (titseln * TITSEL_WIDTH));
> + reg |= sense << (titseln * TITSEL_WIDTH);
> + writel_relaxed(reg, priv->base + offset);
> + raw_spin_unlock_irqrestore(&priv->lock, flags);
> +
> + return 0;
> +}
> +
> +static int rzg2l_irqc_set_type(struct irq_data *d, unsigned int type)
> +{
> + unsigned int hw_irq = irqd_to_hwirq(d);
> +
> + if (hw_irq >= IRQC_IRQ_START && hw_irq <= IRQC_IRQ_COUNT)
> + return rzg2l_irq_set_type(d, type);
> + else if (hw_irq >= IRQC_TINT_START && hw_irq <= IRQC_TINT_COUNT)
> + return rzg2l_tint_set_edge(d, type);
> +
> + return -EINVAL;
> +}
> +
> +static struct irq_chip irqc_chip = {
> + .name = "rzg2l-irqc",
> + .irq_eoi = rzg2l_irqc_eoi,
> + .irq_mask = irq_chip_mask_parent,
> + .irq_unmask = irq_chip_unmask_parent,
> + .irq_disable = rzg2l_irqc_irq_disable,
> + .irq_enable = rzg2l_irqc_irq_enable,

So this looks a bit odd. irq_mask only calls the parent and does nothing
locally, while irq_disable does something locally and calls into the
parent. If the parent is a GIC, this is turned into a mask (GIC has no
notion of disabled).

If that's the flow you expect, good. But please check this is the case.

> + .irq_get_irqchip_state = irq_chip_get_parent_state,
> + .irq_set_irqchip_state = irq_chip_set_parent_state,
> + .irq_retrigger = irq_chip_retrigger_hierarchy,
> + .irq_set_type = rzg2l_irqc_set_type,
> + .flags = IRQCHIP_MASK_ON_SUSPEND |
> + IRQCHIP_SET_TYPE_MASKED |
> + IRQCHIP_SKIP_SET_WAKE,
> +};
> +
> +static int rzg2l_irqc_alloc(struct irq_domain *domain, unsigned int virq,
> + unsigned int nr_irqs, void *arg)
> +{
> + struct rzg2l_irqc_priv *priv = domain->host_data;
> + struct rzg2l_irqc_chip_data *chip_data = NULL;
> + struct irq_fwspec spec;
> + irq_hw_number_t hwirq;
> + int tint = -EINVAL;
> + unsigned int type;
> + unsigned int i;
> + int ret;
> +
> + ret = irq_domain_translate_twocell(domain, arg, &hwirq, &type);
> + if (ret)
> + return ret;
> +
> + /*
> + * For TINIT interrupts ie where pinctrl driver is child of irqc domain
> + * the hwirq and TINT are encoded in fwspec->param[0].
> + * hwirq for TINIT range from 9-40, hwirq is embedded 0-15 bits and TINT
> + * from 16-31 bits. TINIT from the pinctrl driver needs to be programmed
> + * in IRQC registers to enable a given gpio pin as interrupt.
> + */
> + if (hwirq > IRQC_IRQ_COUNT) {
> + tint = TINT_EXTRACT_GPIOINT(hwirq);
> + hwirq = TINT_EXTRACT_HWIRQ(hwirq);
> + }
> +
> + if (hwirq > (IRQC_NUM_IRQ - 1))
> + return -EINVAL;
> +
> + if (tint != -EINVAL && (hwirq < IRQC_TINT_START || hwirq > (IRQC_NUM_IRQ - 1)))
> + return -EINVAL;
> +
> + chip_data = kzalloc(sizeof(*chip_data), GFP_KERNEL);
> + if (!chip_data)
> + return -ENOMEM;
> + chip_data->tint = tint;
> +
> + ret = irq_domain_set_hwirq_and_chip(domain, virq, hwirq, &irqc_chip,
> + chip_data);
> + if (ret) {
> + kfree(chip_data);
> + return ret;
> + }
> +
> + spec.fwnode = domain->parent->fwnode;
> + spec.param_count = priv->map[hwirq].args_count;
> + for (i = 0; i < spec.param_count; i++)
> + spec.param[i] = priv->map[hwirq].args[i];
> +
> + ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, &spec);
> + if (ret)
> + kfree(chip_data);
> +
> + return ret;
> +}
> +
> +static void rzg2l_irqc_domain_free(struct irq_domain *domain, unsigned int virq,
> + unsigned int nr_irqs)
> +{
> + struct irq_data *d;
> +
> + d = irq_domain_get_irq_data(domain, virq);
> + if (d) {
> + struct rzg2l_irqc_chip_data *chip_data = d->chip_data;
> +
> + kfree(chip_data);
> + }
> + irq_domain_free_irqs_common(domain, virq, nr_irqs);
> +}
> +
> +static const struct irq_domain_ops rzg2l_irqc_domain_ops = {
> + .alloc = rzg2l_irqc_alloc,
> + .free = rzg2l_irqc_domain_free,
> + .translate = irq_domain_translate_twocell,
> +};
> +
> +static int rzg2l_irqc_parse_map(struct rzg2l_irqc_priv *priv,
> + struct device_node *np,
> + struct device_node *parent)
> +{
> + unsigned int len, j;
> + const __be32 *range;
> +
> + range = of_get_property(np, "interrupts", &len);
> + if (!range)
> + return -EINVAL;
> +
> + for (len /= sizeof(*range), j = 0; len >= 3; len -= 3) {
> + if (j >= IRQC_NUM_IRQ)
> + return -EINVAL;
> +
> + priv->map[j].args[0] = be32_to_cpu(*range++);
> + priv->map[j].args[1] = be32_to_cpu(*range++);
> + priv->map[j].args[2] = be32_to_cpu(*range++);
> + priv->map[j].args_count = 3;
> + j++;
> + }

I'm confused. Why do you have to invent a new interrupt parser? What
is wrong with of_irq_parse_one() populating the of_phandle_args array?
I expected to see something like:

static void rzg2l_irqc_parse_map(struct rzg2l_irqc_priv *priv,
struct device_node *np)
{
int i;

for (i = 0; i < IRQC_NUM_IRQ; i++)
of_irq_parse_one(np, i, &priv->map[i]);
}

and that's it.

Thanks,

M.

--
Without deviation from the norm, progress is not possible.