diff mbox series

[v5,5/5] pinctrl: renesas: pinctrl-rzg2l: Add IRQ domain to handle GPIO interrupt

Message ID 20220523174238.28942-6-prabhakar.mahadev-lad.rj@bp.renesas.com
State New
Headers show
Series Renesas RZ/G2L IRQC support | expand

Commit Message

Lad Prabhakar May 23, 2022, 5:42 p.m. UTC 
Add IRQ domain to RZ/G2L pinctrl driver to handle GPIO interrupt.

GPIO0-GPIO122 pins can be used as IRQ lines but only 32 pins can be
used as IRQ lines at a given time. Selection of pins as IRQ lines
is handled by IA55 (which is the IRQC block) which sits in between the
GPIO and GIC.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
 drivers/pinctrl/renesas/pinctrl-rzg2l.c | 236 ++++++++++++++++++++++++
 1 file changed, 236 insertions(+)

Comments

Linus Walleij May 24, 2022, 8:57 a.m. UTC | #1 
On Mon, May 23, 2022 at 7:43 PM Lad Prabhakar
<prabhakar.mahadev-lad.rj@bp.renesas.com> wrote:

> Add IRQ domain to RZ/G2L pinctrl driver to handle GPIO interrupt.
>
> GPIO0-GPIO122 pins can be used as IRQ lines but only 32 pins can be
> used as IRQ lines at a given time. Selection of pins as IRQ lines
> is handled by IA55 (which is the IRQC block) which sits in between the
> GPIO and GIC.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

I don't know if I'm too tired or reading it wrong, but it seems you
went through the trouble of making it possible to override .free() in
the irqdomain in patch 3/5 and yet not using it in this patch 5/5?

Yours,
Linus Walleij
Lad, Prabhakar May 24, 2022, 9:01 a.m. UTC | #2 
Hi Linus,

Thank you for the review.

On Tue, May 24, 2022 at 9:57 AM Linus Walleij <linus.walleij@linaro.org> wrote:
>
> On Mon, May 23, 2022 at 7:43 PM Lad Prabhakar
> <prabhakar.mahadev-lad.rj@bp.renesas.com> wrote:
>
> > Add IRQ domain to RZ/G2L pinctrl driver to handle GPIO interrupt.
> >
> > GPIO0-GPIO122 pins can be used as IRQ lines but only 32 pins can be
> > used as IRQ lines at a given time. Selection of pins as IRQ lines
> > is handled by IA55 (which is the IRQC block) which sits in between the
> > GPIO and GIC.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
>
> I don't know if I'm too tired or reading it wrong, but it seems you
> went through the trouble of making it possible to override .free() in
> the irqdomain in patch 3/5 and yet not using it in this patch 5/5?
>
I think you missed it, free callback is overridden with
rzg2l_gpio_irq_domain_free().

[0] https://patchwork.kernel.org/project/linux-renesas-soc/patch/20220523174238.28942-6-prabhakar.mahadev-lad.rj@bp.renesas.com/

Cheers,
Prabhakar
Linus Walleij May 24, 2022, 9:26 a.m. UTC | #3 
On Tue, May 24, 2022 at 11:01 AM Lad, Prabhakar
<prabhakar.csengg@gmail.com> wrote:
> On Tue, May 24, 2022 at 9:57 AM Linus Walleij <linus.walleij@linaro.org> wrote:> >
> > On Mon, May 23, 2022 at 7:43 PM Lad Prabhakar
> > <prabhakar.mahadev-lad.rj@bp.renesas.com> wrote:
> >
> > > Add IRQ domain to RZ/G2L pinctrl driver to handle GPIO interrupt.
> > >
> > > GPIO0-GPIO122 pins can be used as IRQ lines but only 32 pins can be
> > > used as IRQ lines at a given time. Selection of pins as IRQ lines
> > > is handled by IA55 (which is the IRQC block) which sits in between the
> > > GPIO and GIC.
> > >
> > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >
> > I don't know if I'm too tired or reading it wrong, but it seems you
> > went through the trouble of making it possible to override .free() in
> > the irqdomain in patch 3/5 and yet not using it in this patch 5/5?
> >
> I think you missed it, free callback is overridden with
> rzg2l_gpio_irq_domain_free().
>
> [0] https://patchwork.kernel.org/project/linux-renesas-soc/patch/20220523174238.28942-6-prabhakar.mahadev-lad.rj@bp.renesas.com/

Yeah my bad, can't read properly today :/

Why is it necessary to do this stuff in the irqdomain rather than
in the irqchip? Especially this:

+ bitmap_release_region(pctrl->tint_slot, i, get_order(1));

Since the idea with irq_domain is to translate physical (hardware) IRQs
to Linux IRQ numbers, I don't see how this is related to that.

To me it seems you have taken the usecase that is normally
in irqchip and moved it to irqdomain.

To me this seems much more like a job that needs to happen in
the irqchip .irq_enable()/.irq_disable() pair, and which we have
done before in Hans Verkuils patch series:

461c1a7d4733 gpiolib: override irq_enable/disable
4e9439ddacea gpiolib: add flag to indicate if the irq is disabled
ca620f2de153 gliolib: set hooks in gpiochip_set_irq_hooks()

This gets used by drivers such as:
drivers/media/cec/platform/cec-gpio/cec-gpio.c

Where you can see these dynamic calls:

static bool cec_gpio_enable_irq(struct cec_adapter *adap)
{
        struct cec_gpio *cec = cec_get_drvdata(adap);

        enable_irq(cec->cec_irq);
        return true;
}

static void cec_gpio_disable_irq(struct cec_adapter *adap)
{
        struct cec_gpio *cec = cec_get_drvdata(adap);

        disable_irq(cec->cec_irq);
}

Which end up calling .irq_enable()/.irq_disable() on the irq_chip
dynamically enabling/disabling the irq.

If you prefer to have this done in process context up front when
the irq is requested/released then irq_chip also have these
callbacks:

        int             (*irq_request_resources)(struct irq_data *data);
        void            (*irq_release_resources)(struct irq_data *data);

So I would think over the usecase here a bit. Why does this have
to be in the irqdomain?

Yours,
Linus Walleij
Linus Walleij May 24, 2022, 11:58 a.m. UTC | #4 
On Tue, May 24, 2022 at 12:21 PM Lad, Prabhakar
<prabhakar.csengg@gmail.com> wrote:

> Since currently there is no other way to release the resources which are allocated in
> child_to_parent_hwirq()/populate_parent_alloc_arg() callbacks the free callback is
> overridden and the bitmap is released there.
>
> Let me know if there is any other better approach on handling the above and if it
> can be moved into irqchip instead of irqdomain.

I have no idea, as long as Marc Z ACKs the patch, it is good for me, the irqchip
intrinsics has burnt me more than once. (Says the guy who constructed
pin control,
yeah I know my code isn't better!)

Yours,
Linus Walleij
diff mbox series

Patch

diff --git a/drivers/pinctrl/renesas/pinctrl-rzg2l.c b/drivers/pinctrl/renesas/pinctrl-rzg2l.c
index a48cac55152c..0793b5718f68 100644
--- a/drivers/pinctrl/renesas/pinctrl-rzg2l.c
+++ b/drivers/pinctrl/renesas/pinctrl-rzg2l.c
@@ -9,8 +9,10 @@ 
 #include <linux/clk.h>
 #include <linux/gpio/driver.h>
 #include <linux/io.h>
+#include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
+#include <linux/of_irq.h>
 #include <linux/pinctrl/pinconf-generic.h>
 #include <linux/pinctrl/pinconf.h>
 #include <linux/pinctrl/pinctrl.h>
@@ -89,6 +91,7 @@ 
 #define PIN(n)			(0x0800 + 0x10 + (n))
 #define IOLH(n)			(0x1000 + (n) * 8)
 #define IEN(n)			(0x1800 + (n) * 8)
+#define ISEL(n)			(0x2c80 + (n) * 8)
 #define PWPR			(0x3014)
 #define SD_CH(n)		(0x3000 + (n) * 4)
 #define QSPI			(0x3008)
@@ -112,6 +115,10 @@ 
 #define RZG2L_PIN_ID_TO_PORT_OFFSET(id)	(RZG2L_PIN_ID_TO_PORT(id) + 0x10)
 #define RZG2L_PIN_ID_TO_PIN(id)		((id) % RZG2L_PINS_PER_PORT)
 
+#define RZG2L_TINT_MAX_INTERRUPT	32
+#define RZG2L_TINT_IRQ_START_INDEX	9
+#define RZG2L_PACK_HWIRQ(t, i)		(((t) << 16) | (i))
+
 struct rzg2l_dedicated_configs {
 	const char *name;
 	u32 config;
@@ -137,6 +144,9 @@  struct rzg2l_pinctrl {
 
 	struct gpio_chip		gpio_chip;
 	struct pinctrl_gpio_range	gpio_range;
+	DECLARE_BITMAP(tint_slot, RZG2L_TINT_MAX_INTERRUPT);
+	spinlock_t			bitmap_lock;
+	unsigned int			hwirq[RZG2L_TINT_MAX_INTERRUPT];
 
 	spinlock_t			lock;
 };
@@ -883,8 +893,14 @@  static int rzg2l_gpio_get(struct gpio_chip *chip, unsigned int offset)
 
 static void rzg2l_gpio_free(struct gpio_chip *chip, unsigned int offset)
 {
+	unsigned int virq;
+
 	pinctrl_gpio_free(chip->base + offset);
 
+	virq = irq_find_mapping(chip->irq.domain, offset);
+	if (virq)
+		irq_dispose_mapping(virq);
+
 	/*
 	 * Set the GPIO as an input to ensure that the next GPIO request won't
 	 * drive the GPIO pin as an output.
@@ -1104,14 +1120,224 @@  static struct {
 	}
 };
 
+static int rzg2l_gpio_get_gpioint(unsigned int virq)
+{
+	unsigned int gpioint;
+	unsigned int i;
+	u32 port, bit;
+
+	port = virq / 8;
+	bit = virq % 8;
+
+	if (port >= ARRAY_SIZE(rzg2l_gpio_configs) ||
+	    bit >= RZG2L_GPIO_PORT_GET_PINCNT(rzg2l_gpio_configs[port]))
+		return -EINVAL;
+
+	gpioint = bit;
+	for (i = 0; i < port; i++)
+		gpioint += RZG2L_GPIO_PORT_GET_PINCNT(rzg2l_gpio_configs[i]);
+
+	return gpioint;
+}
+
+static void rzg2l_gpio_irq_disable(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct rzg2l_pinctrl *pctrl = container_of(gc, struct rzg2l_pinctrl, gpio_chip);
+	unsigned int hwirq = irqd_to_hwirq(d);
+	unsigned long flags;
+	void __iomem *addr;
+	u32 port;
+	u8 bit;
+
+	port = RZG2L_PIN_ID_TO_PORT(hwirq);
+	bit = RZG2L_PIN_ID_TO_PIN(hwirq);
+
+	addr = pctrl->base + ISEL(port);
+	if (bit >= 4) {
+		bit -= 4;
+		addr += 4;
+	}
+
+	spin_lock_irqsave(&pctrl->lock, flags);
+	writel(readl(addr) & ~BIT(bit * 8), addr);
+	spin_unlock_irqrestore(&pctrl->lock, flags);
+
+	gpiochip_disable_irq(gc, hwirq);
+	irq_chip_disable_parent(d);
+}
+
+static void rzg2l_gpio_irq_enable(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct rzg2l_pinctrl *pctrl = container_of(gc, struct rzg2l_pinctrl, gpio_chip);
+	unsigned int hwirq = irqd_to_hwirq(d);
+	unsigned long flags;
+	void __iomem *addr;
+	u32 port;
+	u8 bit;
+
+	gpiochip_enable_irq(gc, hwirq);
+
+	port = RZG2L_PIN_ID_TO_PORT(hwirq);
+	bit = RZG2L_PIN_ID_TO_PIN(hwirq);
+
+	addr = pctrl->base + ISEL(port);
+	if (bit >= 4) {
+		bit -= 4;
+		addr += 4;
+	}
+
+	spin_lock_irqsave(&pctrl->lock, flags);
+	writel(readl(addr) | BIT(bit * 8), addr);
+	spin_unlock_irqrestore(&pctrl->lock, flags);
+
+	irq_chip_enable_parent(d);
+}
+
+static int rzg2l_gpio_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	return irq_chip_set_type_parent(d, type);
+}
+
+static void rzg2l_gpio_irqc_eoi(struct irq_data *d)
+{
+	irq_chip_eoi_parent(d);
+}
+
+static void rzg2l_gpio_irq_print_chip(struct irq_data *data, struct seq_file *p)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+
+	seq_printf(p, dev_name(gc->parent));
+}
+
+static const struct irq_chip rzg2l_gpio_irqchip = {
+	.name = "rzg2l-gpio",
+	.irq_disable = rzg2l_gpio_irq_disable,
+	.irq_enable = rzg2l_gpio_irq_enable,
+	.irq_mask = irq_chip_mask_parent,
+	.irq_unmask = irq_chip_unmask_parent,
+	.irq_set_type = rzg2l_gpio_irq_set_type,
+	.irq_eoi = rzg2l_gpio_irqc_eoi,
+	.irq_print_chip = rzg2l_gpio_irq_print_chip,
+	.flags = IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
+static int rzg2l_gpio_child_to_parent_hwirq(struct gpio_chip *gc,
+					    unsigned int child,
+					    unsigned int child_type,
+					    unsigned int *parent,
+					    unsigned int *parent_type)
+{
+	struct rzg2l_pinctrl *pctrl = gpiochip_get_data(gc);
+	unsigned long flags;
+	int gpioint, irq;
+
+	gpioint = rzg2l_gpio_get_gpioint(child);
+	if (gpioint < 0)
+		return gpioint;
+
+	spin_lock_irqsave(&pctrl->bitmap_lock, flags);
+	irq = bitmap_find_free_region(pctrl->tint_slot, RZG2L_TINT_MAX_INTERRUPT, get_order(1));
+	spin_unlock_irqrestore(&pctrl->bitmap_lock, flags);
+	if (irq < 0)
+		return -ENOSPC;
+	pctrl->hwirq[irq] = child;
+	irq += RZG2L_TINT_IRQ_START_INDEX;
+
+	/* All these interrupts are level high in the CPU */
+	*parent_type = IRQ_TYPE_LEVEL_HIGH;
+	*parent = RZG2L_PACK_HWIRQ(gpioint, irq);
+	return 0;
+}
+
+static void *rzg2l_gpio_populate_parent_fwspec(struct gpio_chip *chip,
+					       unsigned int parent_hwirq,
+					       unsigned int parent_type)
+{
+	struct irq_fwspec *fwspec;
+
+	fwspec = kzalloc(sizeof(*fwspec), GFP_KERNEL);
+	if (!fwspec)
+		return NULL;
+
+	fwspec->fwnode = chip->irq.parent_domain->fwnode;
+	fwspec->param_count = 2;
+	fwspec->param[0] = parent_hwirq;
+	fwspec->param[1] = parent_type;
+
+	return fwspec;
+}
+
+static void rzg2l_gpio_irq_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 gpio_chip *gc = irq_data_get_irq_chip_data(d);
+		struct rzg2l_pinctrl *pctrl = container_of(gc, struct rzg2l_pinctrl, gpio_chip);
+		irq_hw_number_t hwirq = irqd_to_hwirq(d);
+		unsigned long flags;
+		unsigned int i;
+
+		for (i = 0; i < RZG2L_TINT_MAX_INTERRUPT; i++) {
+			if (pctrl->hwirq[i] == hwirq) {
+				spin_lock_irqsave(&pctrl->bitmap_lock, flags);
+				bitmap_release_region(pctrl->tint_slot, i, get_order(1));
+				spin_unlock_irqrestore(&pctrl->bitmap_lock, flags);
+				pctrl->hwirq[i] = 0;
+				break;
+			}
+		}
+	}
+	irq_domain_free_irqs_common(domain, virq, nr_irqs);
+}
+
+static void rzg2l_init_irq_valid_mask(struct gpio_chip *gc,
+				      unsigned long *valid_mask,
+				      unsigned int ngpios)
+{
+	struct rzg2l_pinctrl *pctrl = gpiochip_get_data(gc);
+	struct gpio_chip *chip = &pctrl->gpio_chip;
+	unsigned int offset;
+
+	/* Forbid unused lines to be mapped as IRQs */
+	for (offset = 0; offset < chip->ngpio; offset++) {
+		u32 port, bit;
+
+		port = offset / 8;
+		bit = offset % 8;
+
+		if (port >= ARRAY_SIZE(rzg2l_gpio_configs) ||
+		    bit >= RZG2L_GPIO_PORT_GET_PINCNT(rzg2l_gpio_configs[port]))
+			clear_bit(offset, valid_mask);
+	}
+}
+
 static int rzg2l_gpio_register(struct rzg2l_pinctrl *pctrl)
 {
 	struct device_node *np = pctrl->dev->of_node;
 	struct gpio_chip *chip = &pctrl->gpio_chip;
 	const char *name = dev_name(pctrl->dev);
+	struct irq_domain *parent_domain;
 	struct of_phandle_args of_args;
+	struct device_node *parent_np;
+	struct gpio_irq_chip *girq;
 	int ret;
 
+	parent_np = of_irq_find_parent(np);
+	if (!parent_np)
+		return -ENXIO;
+
+	parent_domain = irq_find_host(parent_np);
+	of_node_put(parent_np);
+	if (!parent_domain)
+		return -EPROBE_DEFER;
+
 	ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 0, &of_args);
 	if (ret) {
 		dev_err(pctrl->dev, "Unable to parse gpio-ranges\n");
@@ -1138,6 +1364,15 @@  static int rzg2l_gpio_register(struct rzg2l_pinctrl *pctrl)
 	chip->base = -1;
 	chip->ngpio = of_args.args[2];
 
+	girq = &chip->irq;
+	gpio_irq_chip_set_chip(girq, &rzg2l_gpio_irqchip);
+	girq->fwnode = of_node_to_fwnode(np);
+	girq->parent_domain = parent_domain;
+	girq->child_to_parent_hwirq = rzg2l_gpio_child_to_parent_hwirq;
+	girq->populate_parent_alloc_arg = rzg2l_gpio_populate_parent_fwspec;
+	girq->child_irq_domain_ops.free = rzg2l_gpio_irq_domain_free;
+	girq->init_valid_mask = rzg2l_init_irq_valid_mask;
+
 	pctrl->gpio_range.id = 0;
 	pctrl->gpio_range.pin_base = 0;
 	pctrl->gpio_range.base = 0;
@@ -1253,6 +1488,7 @@  static int rzg2l_pinctrl_probe(struct platform_device *pdev)
 	}
 
 	spin_lock_init(&pctrl->lock);
+	spin_lock_init(&pctrl->bitmap_lock);
 
 	platform_set_drvdata(pdev, pctrl);