Re: [PATCH 3/3] use linear irq domain in gpio-dwapb

From: Sebastian Hesselbarth
Date: Tue Nov 05 2013 - 16:32:23 EST

On 11/05/2013 05:55 PM, Alan Tull wrote:
From: Alan Tull <atull@xxxxxxxxxx>

* Changes to get gpio-dwapb (originally v3.2-rc7) driver building and
working on current kernel.
* Use linear irq domain.
* Fix setting irq edge type for 'rising' and 'both'.
* Support as a loadable module.
* Use bgpio_chip's spinlock during register access.

As this patch is basically messing what I have commented before,
I really lost interest in reviewing this again. Please just squash
them into one.

BTW, I do have a driver for dw-apb-gpio that almost looks feature
equivalent to this one. I am not ready for testing on Berlin SoCs,
so I haven't posted it. After the review, I somehow think I should
post it, especially because I see no point in port child nodes.

Anyway, some remarks below.

Signed-off-by: Alan Tull <atull@xxxxxxxxxx>
---
drivers/gpio/Kconfig | 2 +-
drivers/gpio/gpio-dwapb.c | 235 ++++++++++++++++++++++++++++++---------------
2 files changed, 160 insertions(+), 77 deletions(-)

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 4cc26ed..5fc674a 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -122,7 +122,7 @@ config GPIO_GENERIC_PLATFORM
Say yes here to support basic platform_device memory-mapped GPIO controllers.

config GPIO_DWAPB
- bool "Synopsys DesignWare APB GPIO driver"
+ tristate "Synopsys DesignWare APB GPIO driver"
select GPIO_GENERIC
select GENERIC_IRQ_CHIP
depends on OF_GPIO && IRQ_DOMAIN
diff --git a/drivers/gpio/gpio-dwapb.c b/drivers/gpio/gpio-dwapb.c
index 64c7183..cca97e3 100644
--- a/drivers/gpio/gpio-dwapb.c
+++ b/drivers/gpio/gpio-dwapb.c
@@ -18,6 +18,7 @@
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
+#include <linux/spinlock.h>

#define INT_EN_REG_OFFS 0x30
#define INT_MASK_REG_OFFS 0x34
@@ -30,7 +31,6 @@ struct dwapb_gpio;

struct dwapb_gpio_bank {
struct bgpio_chip bgc;
- unsigned int bank_idx;
bool is_registered;
struct dwapb_gpio *gpio;
};
@@ -41,8 +41,9 @@ struct dwapb_gpio {
void __iomem *regs;
struct dwapb_gpio_bank *banks;
unsigned int nr_banks;
- struct irq_chip_generic *irq_gc;
unsigned long toggle_edge;
+ struct irq_domain *domain;
+ int hwirq;
};

static unsigned int dwapb_gpio_nr_banks(struct device_node *of_node)
@@ -63,29 +64,30 @@ static int dwapb_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
dwapb_gpio_bank, bgc);
struct dwapb_gpio *gpio = bank->gpio;

- return irq_domain_to_irq(&gpio->irq_gc->domain, offset);
+ return irq_create_mapping(gpio->domain, offset);
}

static void dwapb_toggle_trigger(struct dwapb_gpio *gpio, unsigned int offs)
{
- u32 v = readl(gpio->regs + INT_TYPE_REG_OFFS);
+ u32 v = readl(gpio->regs + INT_POLARITY_REG_OFFS);

if (gpio_get_value(gpio->banks[0].bgc.gc.base + offs))
v &= ~BIT(offs);
else
v |= BIT(offs);

- writel(v, gpio->regs + INT_TYPE_REG_OFFS);
+ writel(v, gpio->regs + INT_POLARITY_REG_OFFS);
}

static void dwapb_irq_handler(u32 irq, struct irq_desc *desc)
{
struct dwapb_gpio *gpio = irq_get_handler_data(irq);
+ struct irq_chip *chip = irq_desc_get_chip(desc);
u32 irq_status = readl(gpio->regs + INT_STATUS_REG_OFFS);

while (irq_status) {
int irqoffset = fls(irq_status) - 1;
- int irq = irq_domain_to_irq(&gpio->irq_gc->domain, irqoffset);
+ int irq = irq_linear_revmap(gpio->domain, irqoffset);

generic_handle_irq(irq);
irq_status &= ~(1 << irqoffset);
@@ -93,44 +95,56 @@ static void dwapb_irq_handler(u32 irq, struct irq_desc *desc)
if (gpio->toggle_edge & BIT(irqoffset))
dwapb_toggle_trigger(gpio, irqoffset);
}
+
+ if (chip->irq_eoi)
+ chip->irq_eoi(irq_desc_get_irq_data(desc));
}

static void dwapb_irq_enable(struct irq_data *d)
{
- struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
- struct dwapb_gpio *gpio = gc->private;
+ struct dwapb_gpio *gpio = irq_data_get_irq_chip_data(d);
+ struct bgpio_chip *bgc = &gpio->banks[0].bgc;
+ unsigned long flags;
+ u32 val;

- u32 val = readl(gpio->regs + INT_EN_REG_OFFS);
+ spin_lock_irqsave(&bgc->lock, flags);
+ val = readl(gpio->regs + INT_EN_REG_OFFS);
val |= 1 << d->hwirq;
writel(val, gpio->regs + INT_EN_REG_OFFS);
+ spin_unlock_irqrestore(&bgc->lock, flags);
}

static void dwapb_irq_disable(struct irq_data *d)
{
- struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
- struct dwapb_gpio *gpio = gc->private;
+ struct dwapb_gpio *gpio = irq_data_get_irq_chip_data(d);
+ struct bgpio_chip *bgc = &gpio->banks[0].bgc;
+ unsigned long flags;
+ u32 val;

- u32 val = readl(gpio->regs + INT_EN_REG_OFFS);
+ spin_lock_irqsave(&bgc->lock, flags);
+ val = readl(gpio->regs + INT_EN_REG_OFFS);
val &= ~(1 << d->hwirq);
writel(val, gpio->regs + INT_EN_REG_OFFS);
+ spin_unlock_irqrestore(&bgc->lock, flags);
}

static int dwapb_irq_set_type(struct irq_data *d, u32 type)
{
- struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
- struct dwapb_gpio *gpio = gc->private;
+ struct dwapb_gpio *gpio = irq_data_get_irq_chip_data(d);
+ struct bgpio_chip *bgc = &gpio->banks[0].bgc;
int bit = d->hwirq;
- unsigned long level, polarity;
+ unsigned long level, polarity, flags;

if (type & ~(IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING |
IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW))
return -EINVAL;

+ spin_lock_irqsave(&bgc->lock, flags);
level = readl(gpio->regs + INT_TYPE_REG_OFFS);
polarity = readl(gpio->regs + INT_POLARITY_REG_OFFS);

gpio->toggle_edge &= ~BIT(bit);
- if (type & IRQ_TYPE_EDGE_BOTH) {
+ if (type == IRQ_TYPE_EDGE_BOTH) {
gpio->toggle_edge |= BIT(bit);
level |= (1 << bit);
dwapb_toggle_trigger(gpio, bit);
@@ -150,72 +164,102 @@ static int dwapb_irq_set_type(struct irq_data *d, u32 type)

writel(level, gpio->regs + INT_TYPE_REG_OFFS);
writel(polarity, gpio->regs + INT_POLARITY_REG_OFFS);
+ spin_unlock_irqrestore(&bgc->lock, flags);

return 0;
}

-static int dwapb_create_irqchip(struct dwapb_gpio *gpio,
- struct dwapb_gpio_bank *bank,
- unsigned int irq_base)
+static void dwapb_irq_ack(struct irq_data *d)
{
- struct irq_chip_type *ct;
-
- gpio->irq_gc = irq_alloc_generic_chip("gpio-dwapb", 1, irq_base,
- gpio->regs, handle_level_irq);
- if (!gpio->irq_gc)
- return -EIO;
-
- gpio->irq_gc->domain.of_node = of_node_get(bank->bgc.gc.of_node);
- gpio->irq_gc->private = gpio;
- ct = gpio->irq_gc->chip_types;
- ct->chip.irq_ack = irq_gc_ack_set_bit;
- ct->chip.irq_mask = irq_gc_mask_set_bit;
- ct->chip.irq_unmask = irq_gc_mask_clr_bit;
- ct->chip.irq_set_type = dwapb_irq_set_type;
- ct->chip.irq_enable = dwapb_irq_enable;
- ct->chip.irq_disable = dwapb_irq_disable;
- ct->regs.ack = EOI_REG_OFFS;
- ct->regs.mask = INT_MASK_REG_OFFS;
- irq_setup_generic_chip(gpio->irq_gc, IRQ_MSK(bank->bgc.gc.ngpio),
- IRQ_GC_INIT_NESTED_LOCK, IRQ_NOREQUEST, 0);
+ struct dwapb_gpio *gpio = irq_data_get_irq_chip_data(d);
+ struct bgpio_chip *bgc = &gpio->banks[0].bgc;
+ unsigned long flags;

- return 0;
+ spin_lock_irqsave(&bgc->lock, flags);
+ writel(1 << d->hwirq, gpio->regs + EOI_REG_OFFS);
+ spin_unlock_irqrestore(&bgc->lock, flags);
}

-static int dwapb_configure_irqs(struct dwapb_gpio *gpio,
- struct dwapb_gpio_bank *bank)
+static void dwapb_irq_mask(struct irq_data *d)
{
- unsigned int m, irq, ngpio = bank->bgc.gc.ngpio;
- int irq_base;
-
- for (m = 0; m < ngpio; ++m) {
- irq = irq_of_parse_and_map(bank->bgc.gc.of_node, m);
- if (!irq && m == 0) {
- dev_warn(gpio->dev, "no irq for bank %s\n",
- bank->bgc.gc.of_node->full_name);
- return -ENXIO;
- } else if (!irq) {
- break;
- }
-
- irq_set_chained_handler(irq, dwapb_irq_handler);
- irq_set_handler_data(irq, gpio);
- }
- bank->bgc.gc.to_irq = dwapb_gpio_to_irq;
+ struct dwapb_gpio *gpio = irq_data_get_irq_chip_data(d);
+ struct bgpio_chip *bgc = &gpio->banks[0].bgc;
+ unsigned long value, flags;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+ value = readl(gpio->regs + INT_MASK_REG_OFFS);
+ value |= 1 << d->hwirq;
+ writel(value, gpio->regs + INT_MASK_REG_OFFS);
+ spin_unlock_irqrestore(&bgc->lock, flags);
+}

- irq_base = irq_alloc_descs(-1, 0, ngpio, NUMA_NO_NODE);
- if (irq_base < 0)
- return irq_base;
+static void dwapb_irq_unmask(struct irq_data *d)
+{
+ struct dwapb_gpio *gpio = irq_data_get_irq_chip_data(d);
+ struct bgpio_chip *bgc = &gpio->banks[0].bgc;
+ unsigned long value, flags;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+ value = readl(gpio->regs + INT_MASK_REG_OFFS);
+ value &= ~(1 << d->hwirq);
+ writel(value, gpio->regs + INT_MASK_REG_OFFS);
+ spin_unlock_irqrestore(&bgc->lock, flags);
+}

- if (dwapb_create_irqchip(gpio, bank, irq_base))
- goto out_free_descs;
+static struct irq_chip dwapb_irq_chip = {
+ .name = "gpio-dwapb",
+ .irq_ack = dwapb_irq_ack,
+ .irq_mask = dwapb_irq_mask,
+ .irq_unmask = dwapb_irq_unmask,
+ .irq_set_type = dwapb_irq_set_type,
+ .irq_enable = dwapb_irq_enable,
+ .irq_disable = dwapb_irq_disable,
+};
+
+static int dwapb_gpio_irq_map(struct irq_domain *domain,
+ unsigned int irq,
+ irq_hw_number_t hwirq)
+{
+ struct dwapb_gpio *gpio = domain->host_data;
+
+ irq_set_chip_data(irq, gpio);
+ irq_set_chip_and_handler(irq, &dwapb_irq_chip, handle_level_irq);
+ irq_set_irq_type(irq, IRQ_TYPE_NONE);
+ irq_set_handler_data(irq, gpio);

return 0;
+}

-out_free_descs:
- irq_free_descs(irq_base, ngpio);
+static struct irq_domain_ops dwapb_gpio_irq_ops = {
+ .map = dwapb_gpio_irq_map,
+ .xlate = irq_domain_xlate_twocell,
+};

- return -EIO;
+static void dwapb_configure_irqs(struct dwapb_gpio *gpio,
+ struct dwapb_gpio_bank *bank)
+{
+ struct gpio_chip *gc = &bank->bgc.gc;
+ struct device_node *node = gc->of_node;
+ unsigned int ngpio = gc->ngpio;
+ int reg;
+
+ if (of_get_property(node, "interrupts", &reg) == NULL)
+ return;
+
+ gpio->hwirq = irq_of_parse_and_map(node, 0);
+ if (gpio->hwirq == NO_IRQ)
+ return;
+
+ gpio->domain = irq_domain_add_linear(node, ngpio, &dwapb_gpio_irq_ops,
+ gpio);
+ if (!gpio->domain) {
+ irq_dispose_mapping(gpio->hwirq);
+ return;
+ }
+
+ irq_set_handler_data(gpio->hwirq, gpio);
+ irq_set_chained_handler(gpio->hwirq, dwapb_irq_handler);
+ bank->bgc.gc.to_irq = dwapb_gpio_to_irq;
}

static int dwapb_gpio_add_bank(struct dwapb_gpio *gpio,
@@ -240,7 +284,6 @@ static int dwapb_gpio_add_bank(struct dwapb_gpio *gpio,
return -EINVAL;
}

- bank->bank_idx = bank_idx;
err = bgpio_init(&bank->bgc, gpio->dev, 4,
gpio->regs + 0x50 + (bank_idx * 0x4),
gpio->regs + 0x00 + (bank_idx * 0xc),
@@ -282,7 +325,7 @@ static void dwapb_gpio_unregister(struct dwapb_gpio *gpio)
of_node_put(gpio->of_node);
}

-static int __devinit dwapb_gpio_probe(struct platform_device *pdev)
+static int dwapb_gpio_probe(struct platform_device *pdev)
{
struct resource *res;
struct dwapb_gpio *gpio;
@@ -296,21 +339,29 @@ static int __devinit dwapb_gpio_probe(struct platform_device *pdev)
gpio->dev = &pdev->dev;

gpio->nr_banks = dwapb_gpio_nr_banks(pdev->dev.of_node);
- if (!gpio->nr_banks)
- return -EINVAL;
+ if (!gpio->nr_banks) {
+ err = -EINVAL;
+ goto out_err;
+ }
gpio->banks = devm_kzalloc(&pdev->dev, gpio->nr_banks *
sizeof(*gpio->banks), GFP_KERNEL);
- if (!gpio->banks)
- return -ENOMEM;
+ if (!gpio->banks) {
+ err = -ENOMEM;
+ goto out_err;
+ }

res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(&pdev->dev, "failed to get iomem\n");
- return -ENXIO;
+ err = -ENXIO;
+ goto out_free_banks;
}
+
gpio->regs = devm_ioremap(&pdev->dev, res->start, resource_size(res));
- if (!gpio->regs)
- return -ENOMEM;
+ if (!gpio->regs) {
+ err = -ENOMEM;
+ goto out_free_banks;
+ }

gpio->of_node = of_node_get(pdev->dev.of_node);
for_each_child_of_node(pdev->dev.of_node, np) {
@@ -325,9 +376,34 @@ static int __devinit dwapb_gpio_probe(struct platform_device *pdev)
out_unregister:
dwapb_gpio_unregister(gpio);

+ if (gpio->domain) {
+ irq_dispose_mapping(gpio->hwirq);
+ irq_domain_remove(gpio->domain);
+ }
+
+out_free_banks:
+ devm_kfree(&pdev->dev, gpio->banks);
+
+out_err:
+ devm_kfree(&pdev->dev, gpio);

devm_ will take care of kfree for you.

return err;
}

+static int dwapb_gpio_remove(struct platform_device *pdev)
+{
+ struct dwapb_gpio *gpio = platform_get_drvdata(pdev);
+
+ dwapb_gpio_unregister(gpio);
+ if (gpio->domain) {
+ irq_dispose_mapping(gpio->hwirq);
+ irq_domain_remove(gpio->domain);
+ }
+ devm_kfree(&pdev->dev, gpio->banks);
+ devm_kfree(&pdev->dev, gpio);

ditto.

+
+ return 0;
+}
+
static const struct of_device_id dwapb_of_match_table[] = {
{ .compatible = "snps,dw-apb-gpio" },
{ /* Sentinel */ }
@@ -340,6 +416,7 @@ static struct platform_driver dwapb_gpio_driver = {
.of_match_table = dwapb_of_match_table,
},
.probe = dwapb_gpio_probe,
+ .remove = dwapb_gpio_remove,
};

static int __init dwapb_gpio_init(void)
@@ -348,6 +425,12 @@ static int __init dwapb_gpio_init(void)
}
postcore_initcall(dwapb_gpio_init);

+static void __exit dwapb_gpio_exit(void)
+{
+ platform_driver_unregister(&dwapb_gpio_driver);
+}
+module_exit(dwapb_gpio_exit);

module_platform_driver() for _init and _exit above and get rid
of postcore_initcall?

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jamie Iles");
MODULE_DESCRIPTION("Synopsys DesignWare APB GPIO driver");


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