RE: [PATCH v1 5/6] TODO: gpio: mlxbf2: Introduce IRQ support
From: Asmaa Mnebhi
Date: Mon Aug 16 2021 - 17:34:58 EST
Hi Andy,
Thanks for your help!
Please see my comments/questions below.
-----Original Message-----
From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Sent: Monday, August 16, 2021 8:00 AM
To: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>; David Thompson <davthompson@xxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx; linux-gpio@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx
Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>; Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>; David S. Miller <davem@xxxxxxxxxxxxx>; Jakub Kicinski <kuba@xxxxxxxxxx>; Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>; Asmaa Mnebhi <asmaa@xxxxxxxxxx>; Liming Sun <limings@xxxxxxxxxx>
Subject: [PATCH v1 5/6] TODO: gpio: mlxbf2: Introduce IRQ support
Importance: High
TBD
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
drivers/gpio/gpio-mlxbf2.c | 106 +++++++++++++++++++++++++++++++++++++
1 file changed, 106 insertions(+)
diff --git a/drivers/gpio/gpio-mlxbf2.c b/drivers/gpio/gpio-mlxbf2.c index 3ed95e958c17..bd4c29120b62 100644
--- a/drivers/gpio/gpio-mlxbf2.c
+++ b/drivers/gpio/gpio-mlxbf2.c
@@ -43,9 +43,13 @@
#define YU_GPIO_MODE0 0x0c
#define YU_GPIO_DATASET 0x14
#define YU_GPIO_DATACLEAR 0x18
+#define YU_GPIO_CAUSE_FALL_EN 0x48
#define YU_GPIO_MODE1_CLEAR 0x50
#define YU_GPIO_MODE0_SET 0x54
#define YU_GPIO_MODE0_CLEAR 0x58
+#define YU_GPIO_CAUSE_OR_CAUSE_EVTEN0 0x80
+#define YU_GPIO_CAUSE_OR_EVTEN0 0x94
+#define YU_GPIO_CAUSE_OR_CLRCAUSE 0x98
struct mlxbf2_gpio_context_save_regs {
u32 gpio_mode0;
@@ -218,6 +222,108 @@ static int mlxbf2_gpio_direction_output(struct gpio_chip *chip,
return ret;
}
+static void mlxbf2_gpio_irq_enable(struct mlxbf2_gpio_context *gs, int
+offset) {
+ unsigned long flags;
+ u32 val;
+
+ spin_lock_irqsave(&gs->gc.bgpio_lock, flags);
+ val = readl(gs->gpio_io + YU_GPIO_CAUSE_OR_CLRCAUSE);
+ val |= BIT(offset);
+ writel(val, gs->gpio_io + YU_GPIO_CAUSE_OR_CLRCAUSE);
+
+ /* The INT_N interrupt level is active low.
+ * So enable cause fall bit to detect when GPIO
+ * state goes low.
+ */
+ val = readl(gs->gpio_io + YU_GPIO_CAUSE_FALL_EN);
+ val |= BIT(offset);
+ writel(val, gs->gpio_io + YU_GPIO_CAUSE_FALL_EN);
+
+ /* Enable PHY interrupt by setting the priority level */
+ val = readl(gs->gpio_io + YU_GPIO_CAUSE_OR_EVTEN0);
+ val |= BIT(offset);
+ writel(val, gs->gpio_io + YU_GPIO_CAUSE_OR_EVTEN0);
+ spin_unlock_irqrestore(&gs->gc.bgpio_lock, flags); }
+
+static void mlxbf2_gpio_irq_disable(struct mlxbf2_gpio_context *gs, int
+offset) {
+ unsigned long flags;
+ u32 val;
+
+ spin_lock_irqsave(&gs->gc.bgpio_lock, flags);
+ val = readl(gs->gpio_io + YU_GPIO_CAUSE_OR_EVTEN0);
+ val &= ~BIT(offset);
+ writel(val, gs->gpio_io + YU_GPIO_CAUSE_OR_EVTEN0);
+ spin_unlock_irqrestore(&gs->gc.bgpio_lock, flags); }
+
+static void mlxbf2_gpio_irq_ack(struct mlxbf2_gpio_context *gs, int
+offset) {
+ unsigned long flags;
+ u32 val;
+
+ spin_lock_irqsave(&gs->gc.bgpio_lock, flags);
+ val = readl(gs->gpio_io + YU_GPIO_CAUSE_OR_CLRCAUSE);
+ val |= BIT(offset);
+ writel(val, gs->gpio_io + YU_GPIO_CAUSE_OR_CLRCAUSE);
+ spin_unlock_irqrestore(&gs->gc.bgpio_lock, flags); }
+
+static irqreturn_t mlxbf2_gpio_irq_handler(int irq, void *ptr) {
So how do you suggest registering this handler?
1) should I still use BF_RSH0_DEVICE_YU_INT shared interrupt signal?
2) or does Linux kernel know (based on parsing GpioInt) how trigger the handler based on the GPIO datain changing (active low/high)? In this case, the kernel will call this handler whenever the GPIO pin (9 or 12) value changes. I need to check whether GPIO is active low/high but lets assume for now it is open drain active low. We will use acpi_dev_gpio_irq_get to translate GpioInt to a Linux IRQ number:
irq = acpi_dev_gpio_irq_get_by(ACPI_COMPANION(dev), " phy-gpios ", 0);
ret = devm_request_irq(dev, irq, mlxbf2_gpio_irq_handler, IRQF_ONESHOT | IRQF_SHARED, dev_name(dev), gs);
And I will need to add GpioInt to the GPI0 ACPI table as follows:
// GPIO Controller
Device(GPI0) {
Name(_HID, "MLNXBF22")
Name(_UID, Zero)
Name(_CCA, 1)
Name(_CRS, ResourceTemplate() {
// for gpio[0] yu block
Memory32Fixed(ReadWrite, 0x0280c000, 0x00000100)
GpioInt (Level, ActiveLow, Exclusive, PullDefault, , " \\_SB.GPI0") {9}
})
Name(_DSD, Package() {
ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
Package() {
Package () { "phy-gpios", Package() {^GPI0, 0, 0, 0 }},
Package () { "rst-pin", 32 }, // GPIO pin triggering soft reset on BlueSphere and PRIS
}
})
}
+ struct mlxbf2_gpio_context *gs = ptr;
+ struct gpio_chip *gc = &gs->gc;
+ unsigned long pending;
+ u32 level;
+
+ pending = readl(gs->gpio_io + YU_GPIO_CAUSE_OR_CAUSE_EVTEN0);
+ for_each_set_bit(level, &pending, gc->ngpio) {
+ int nested_irq = irq_find_mapping(gc->irq.domain, level);
+
+ handle_nested_irq(nested_irq);
Now how can the mlxbf_gige_main.c driver also retrieve this nested_irq to register its interrupt handler as well? This irq.domain is only visible to the gpio-mlxbf2.c driver isn't it?
phydev->irq (below) should be populated with nested_irq at init time because it is used to register the phy interrupt in this generic function:
void phy_request_interrupt(struct phy_device *phydev)
{
int err;
err = request_threaded_irq(phydev->irq, NULL, phy_interrupt,
IRQF_ONESHOT | IRQF_SHARED,
phydev_name(phydev), phydev);
if (err) {
phydev_warn(phydev, "Error %d requesting IRQ %d, falling back to polling\n",
err, phydev->irq);
phydev->irq = PHY_POLL;
} else {
if (phy_enable_interrupts(phydev)) {
phydev_warn(phydev, "Can't enable interrupt, falling back to polling\n");
phy_free_interrupt(phydev);
phydev->irq = PHY_POLL;
}
}
}
EXPORT_SYMBOL(phy_request_interrupt);
+ }
+
+ return IRQ_RETVAL(pending);
+}
+
+static void mlxbf2_gpio_irq_mask(struct irq_data *irqd) {
+ struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+ struct mlxbf2_gpio_context *gs = gpiochip_get_data(gc);
+ int offset = irqd_to_hwirq(irqd) % MLXBF2_GPIO_MAX_PINS_PER_BLOCK;
Why is the modulo needed? Isn't the hwirq returned a number between 0 and MLXBF2_GPIO_MAX_PINS_PER_BLOCK-1 ?
+
+ mlxbf2_gpio_irq_disable(gs, offset);
+}
+
+static void mlxbf2_gpio_irq_unmask(struct irq_data *irqd) {
+ struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+ struct mlxbf2_gpio_context *gs = gpiochip_get_data(gc);
+ int offset = irqd_to_hwirq(irqd) % MLXBF2_GPIO_MAX_PINS_PER_BLOCK;
+
+ mlxbf2_gpio_irq_enable(gs, offset);
+}
+
+static void mlxbf2_gpio_irq_bus_lock(struct irq_data *irqd) {
+ mutex_lock(yu_arm_gpio_lock_param.lock);
+}
+
+static void mlxbf2_gpio_irq_bus_sync_unlock(struct irq_data *irqd) {
+ mutex_unlock(yu_arm_gpio_lock_param.lock);
+}
+
+static struct irq_chip mlxbf2_gpio_irq_chip = {
+ .name = "mlxbf2_gpio",
+ .irq_mask = mlxbf2_gpio_irq_mask,
+ .irq_unmask = mlxbf2_gpio_irq_unmask,
+ .irq_bus_lock = mlxbf2_gpio_irq_bus_lock,
+ .irq_bus_sync_unlock = mlxbf2_gpio_irq_bus_sync_unlock,
+};
+
We also need to make sure that the gpio driver is loaded before the mlxbf-gige driver. Otherwise, the mlxbf-gige 1G interface fails to come up. I have implemented this dependency on the gpio driver before, something like this at the end of the mlxbf-gige driver:
MODULE_SOFTDEP("pre: gpio_mlxbf2");
/* BlueField-2 GPIO driver initialization routine. */ static int mlxbf2_gpio_probe(struct platform_device *pdev)
--
2.30.2