net: dsa: b53: Make SRAB driver manage port interrupts

Update the SRAB driver to manage per-port interrupts. Since we cannot
sleep during b53_io_ops, schedule a workqueue whenever we get a port
specific interrupt. We will later make use of this to call back into
PHYLINK when there is e.g: a link state change.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/b53/b53_srab.c

@@ -19,6 +19,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/delay.h>
+#include <linux/interrupt.h>
 #include <linux/platform_device.h>
 #include <linux/platform_data/b53.h>
 #include <linux/of.h>
@@ -47,6 +48,7 @@
 
 /* command and status register of the SRAB */
 #define B53_SRAB_CTRLS			0x40
+#define  B53_SRAB_CTRLS_HOST_INTR	BIT(1)
 #define  B53_SRAB_CTRLS_RCAREQ		BIT(3)
 #define  B53_SRAB_CTRLS_RCAGNT		BIT(4)
 #define  B53_SRAB_CTRLS_SW_INIT_DONE	BIT(6)
@@ -60,8 +62,16 @@
 #define  B53_SRAB_P7_SLEEP_TIMER	BIT(11)
 #define  B53_SRAB_IMP0_SLEEP_TIMER	BIT(12)
 
+struct b53_srab_port_priv {
+	int irq;
+	bool irq_enabled;
+	struct b53_device *dev;
+	unsigned int num;
+};
+
 struct b53_srab_priv {
 	void __iomem *regs;
+	struct b53_srab_port_priv port_intrs[B53_N_PORTS];
 };
 
 static int b53_srab_request_grant(struct b53_device *dev)
@@ -344,6 +354,49 @@ static int b53_srab_write64(struct b53_device *dev, u8 page, u8 reg,
 	return ret;
 }
 
+static irqreturn_t b53_srab_port_thread(int irq, void *dev_id)
+{
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t b53_srab_port_isr(int irq, void *dev_id)
+{
+	struct b53_srab_port_priv *port = dev_id;
+	struct b53_device *dev = port->dev;
+	struct b53_srab_priv *priv = dev->priv;
+
+	/* Acknowledge the interrupt */
+	writel(BIT(port->num), priv->regs + B53_SRAB_INTR);
+
+	return IRQ_WAKE_THREAD;
+}
+
+static int b53_srab_irq_enable(struct b53_device *dev, int port)
+{
+	struct b53_srab_priv *priv = dev->priv;
+	struct b53_srab_port_priv *p = &priv->port_intrs[port];
+	int ret;
+
+	ret = request_threaded_irq(p->irq, b53_srab_port_isr,
+				   b53_srab_port_thread, 0,
+				   dev_name(dev->dev), p);
+	if (!ret)
+		p->irq_enabled = true;
+
+	return ret;
+}
+
+static void b53_srab_irq_disable(struct b53_device *dev, int port)
+{
+	struct b53_srab_priv *priv = dev->priv;
+	struct b53_srab_port_priv *p = &priv->port_intrs[port];
+
+	if (p->irq_enabled) {
+		free_irq(p->irq, p);
+		p->irq_enabled = false;
+	}
+}
+
 static const struct b53_io_ops b53_srab_ops = {
 	.read8 = b53_srab_read8,
 	.read16 = b53_srab_read16,
@@ -355,6 +408,8 @@ static const struct b53_io_ops b53_srab_ops = {
 	.write32 = b53_srab_write32,
 	.write48 = b53_srab_write48,
 	.write64 = b53_srab_write64,
+	.irq_enable = b53_srab_irq_enable,
+	.irq_disable = b53_srab_irq_disable,
 };
 
 static const struct of_device_id b53_srab_of_match[] = {
@@ -379,6 +434,52 @@ static const struct of_device_id b53_srab_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, b53_srab_of_match);
 
+static void b53_srab_intr_set(struct b53_srab_priv *priv, bool set)
+{
+	u32 reg;
+
+	reg = readl(priv->regs + B53_SRAB_CTRLS);
+	if (set)
+		reg |= B53_SRAB_CTRLS_HOST_INTR;
+	else
+		reg &= ~B53_SRAB_CTRLS_HOST_INTR;
+	writel(reg, priv->regs + B53_SRAB_CTRLS);
+}
+
+static void b53_srab_prepare_irq(struct platform_device *pdev)
+{
+	struct b53_device *dev = platform_get_drvdata(pdev);
+	struct b53_srab_priv *priv = dev->priv;
+	struct b53_srab_port_priv *port;
+	unsigned int i;
+	char *name;
+
+	/* Clear all pending interrupts */
+	writel(0xffffffff, priv->regs + B53_SRAB_INTR);
+
+	if (dev->pdata && dev->pdata->chip_id != BCM58XX_DEVICE_ID)
+		return;
+
+	for (i = 0; i < B53_N_PORTS; i++) {
+		port = &priv->port_intrs[i];
+
+		/* There is no port 6 */
+		if (i == 6)
+			continue;
+
+		name = kasprintf(GFP_KERNEL, "link_state_p%d", i);
+		if (!name)
+			return;
+
+		port->num = i;
+		port->dev = dev;
+		port->irq = platform_get_irq_byname(pdev, name);
+		kfree(name);
+	}
+
+	b53_srab_intr_set(priv, true);
+}
+
 static int b53_srab_probe(struct platform_device *pdev)
 {
 	struct b53_platform_data *pdata = pdev->dev.platform_data;
@@ -417,13 +518,17 @@ static int b53_srab_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, dev);
 
+	b53_srab_prepare_irq(pdev);
+
 	return b53_switch_register(dev);
 }
 
 static int b53_srab_remove(struct platform_device *pdev)
 {
 	struct b53_device *dev = platform_get_drvdata(pdev);
+	struct b53_srab_priv *priv = dev->priv;
 
+	b53_srab_intr_set(priv, false);
 	if (dev)
 		b53_switch_remove(dev);