1 files changed, 344 insertions, 0 deletions

diff --git a/drivers/net/ipa/ipa_interrupt.c b/drivers/net/ipa/ipa_interrupt.c
new file mode 100644
index 000000000000..8336596b1247
--- /dev/null
+++ b/drivers/net/ipa/ipa_interrupt.c
@@ -0,0 +1,344 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/* Copyright (c) 2014-2018, The Linux Foundation. All rights reserved.
+ * Copyright (C) 2018-2024 Linaro Ltd.
+ */
+
+/* DOC: IPA Interrupts
+ *
+ * The IPA has an interrupt line distinct from the interrupt used by the GSI
+ * code.  Whereas GSI interrupts are generally related to channel events (like
+ * transfer completions), IPA interrupts are related to other events related
+ * to the IPA.  Some of the IPA interrupts come from a microcontroller
+ * embedded in the IPA.  Each IPA interrupt type can be both masked and
+ * acknowledged independent of the others.
+ *
+ * Two of the IPA interrupts are initiated by the microcontroller.  A third
+ * can be generated to signal the need for a wakeup/resume when an IPA
+ * endpoint has been suspended.  There are other IPA events, but at this
+ * time only these three are supported.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/pm_wakeirq.h>
+#include <linux/types.h>
+
+#include "ipa.h"
+#include "ipa_endpoint.h"
+#include "ipa_interrupt.h"
+#include "ipa_power.h"
+#include "ipa_reg.h"
+#include "ipa_uc.h"
+
+/**
+ * struct ipa_interrupt - IPA interrupt information
+ * @ipa:		IPA pointer
+ * @irq:		Linux IRQ number used for IPA interrupts
+ * @enabled:		Mask indicating which interrupts are enabled
+ * @suspend_enabled:	Bitmap of endpoints with the SUSPEND interrupt enabled
+ */
+struct ipa_interrupt {
+	struct ipa *ipa;
+	u32 irq;
+	u32 enabled;
+	unsigned long *suspend_enabled;
+};
+
+/* Clear the suspend interrupt for all endpoints that signaled it */
+static void ipa_interrupt_suspend_clear_all(struct ipa_interrupt *interrupt)
+{
+	struct ipa *ipa = interrupt->ipa;
+	u32 unit_count;
+	u32 unit;
+
+	unit_count = DIV_ROUND_UP(ipa->endpoint_count, 32);
+	for (unit = 0; unit < unit_count; unit++) {
+		const struct reg *reg;
+		u32 val;
+
+		reg = ipa_reg(ipa, IRQ_SUSPEND_INFO);
+		val = ioread32(ipa->reg_virt + reg_n_offset(reg, unit));
+
+		/* SUSPEND interrupt status isn't cleared on IPA version 3.0 */
+		if (!val || ipa->version == IPA_VERSION_3_0)
+			continue;
+
+		reg = ipa_reg(ipa, IRQ_SUSPEND_CLR);
+		iowrite32(val, ipa->reg_virt + reg_n_offset(reg, unit));
+	}
+}
+
+/* Process a particular interrupt type that has been received */
+static void ipa_interrupt_process(struct ipa_interrupt *interrupt, u32 irq_id)
+{
+	struct ipa *ipa = interrupt->ipa;
+	const struct reg *reg;
+	u32 mask = BIT(irq_id);
+	u32 offset;
+
+	reg = ipa_reg(ipa, IPA_IRQ_CLR);
+	offset = reg_offset(reg);
+
+	switch (irq_id) {
+	case IPA_IRQ_UC_0:
+	case IPA_IRQ_UC_1:
+		/* For microcontroller interrupts, clear the interrupt right
+		 * away, "to avoid clearing unhandled interrupts."
+		 */
+		iowrite32(mask, ipa->reg_virt + offset);
+		ipa_uc_interrupt_handler(ipa, irq_id);
+		break;
+
+	case IPA_IRQ_TX_SUSPEND:
+		/* Clearing the SUSPEND_TX interrupt also clears the
+		 * register that tells us which suspended endpoint(s)
+		 * caused the interrupt, so defer clearing until after
+		 * the handler has been called.
+		 */
+		ipa_interrupt_suspend_clear_all(interrupt);
+		fallthrough;
+
+	default:	/* Silently ignore (and clear) any other condition */
+		iowrite32(mask, ipa->reg_virt + offset);
+		break;
+	}
+}
+
+/* IPA IRQ handler is threaded */
+static irqreturn_t ipa_isr_thread(int irq, void *dev_id)
+{
+	struct ipa_interrupt *interrupt = dev_id;
+	struct ipa *ipa = interrupt->ipa;
+	u32 enabled = interrupt->enabled;
+	struct device *dev = ipa->dev;
+	const struct reg *reg;
+	u32 pending;
+	u32 offset;
+	u32 mask;
+	int ret;
+
+	ret = pm_runtime_get_sync(dev);
+	if (WARN_ON(ret < 0))
+		goto out_power_put;
+
+	/* The status register indicates which conditions are present,
+	 * including conditions whose interrupt is not enabled.  Handle
+	 * only the enabled ones.
+	 */
+	reg = ipa_reg(ipa, IPA_IRQ_STTS);
+	offset = reg_offset(reg);
+	pending = ioread32(ipa->reg_virt + offset);
+	while ((mask = pending & enabled)) {
+		do {
+			u32 irq_id = __ffs(mask);
+
+			mask ^= BIT(irq_id);
+
+			ipa_interrupt_process(interrupt, irq_id);
+		} while (mask);
+		pending = ioread32(ipa->reg_virt + offset);
+	}
+
+	/* If any disabled interrupts are pending, clear them */
+	if (pending) {
+		dev_dbg(dev, "clearing disabled IPA interrupts 0x%08x\n",
+			pending);
+		reg = ipa_reg(ipa, IPA_IRQ_CLR);
+		iowrite32(pending, ipa->reg_virt + reg_offset(reg));
+	}
+out_power_put:
+	(void)pm_runtime_put_autosuspend(dev);
+
+	return IRQ_HANDLED;
+}
+
+static void ipa_interrupt_enabled_update(struct ipa *ipa)
+{
+	const struct reg *reg = ipa_reg(ipa, IPA_IRQ_EN);
+
+	iowrite32(ipa->interrupt->enabled, ipa->reg_virt + reg_offset(reg));
+}
+
+/* Enable an IPA interrupt type */
+void ipa_interrupt_enable(struct ipa *ipa, enum ipa_irq_id ipa_irq)
+{
+	/* Update the IPA interrupt mask to enable it */
+	ipa->interrupt->enabled |= BIT(ipa_irq);
+	ipa_interrupt_enabled_update(ipa);
+}
+
+/* Disable an IPA interrupt type */
+void ipa_interrupt_disable(struct ipa *ipa, enum ipa_irq_id ipa_irq)
+{
+	/* Update the IPA interrupt mask to disable it */
+	ipa->interrupt->enabled &= ~BIT(ipa_irq);
+	ipa_interrupt_enabled_update(ipa);
+}
+
+void ipa_interrupt_irq_disable(struct ipa *ipa)
+{
+	disable_irq(ipa->interrupt->irq);
+}
+
+void ipa_interrupt_irq_enable(struct ipa *ipa)
+{
+	enable_irq(ipa->interrupt->irq);
+}
+
+/* Common function used to enable/disable TX_SUSPEND for an endpoint */
+static void ipa_interrupt_suspend_control(struct ipa_interrupt *interrupt,
+					  u32 endpoint_id, bool enable)
+{
+	struct ipa *ipa = interrupt->ipa;
+	u32 mask = BIT(endpoint_id % 32);
+	u32 unit = endpoint_id / 32;
+	const struct reg *reg;
+	unsigned long weight;
+	u32 offset;
+	u32 val;
+
+	WARN_ON(!test_bit(endpoint_id, ipa->available));
+
+	/* IPA version 3.0 does not support TX_SUSPEND interrupt control */
+	if (ipa->version == IPA_VERSION_3_0)
+		return;
+
+	weight = bitmap_weight(interrupt->suspend_enabled, ipa->endpoint_count);
+	if (weight == 1 && !enable)
+		ipa_interrupt_disable(ipa, IPA_IRQ_TX_SUSPEND);
+
+	reg = ipa_reg(ipa, IRQ_SUSPEND_EN);
+	offset = reg_n_offset(reg, unit);
+	val = ioread32(ipa->reg_virt + offset);
+
+	if (enable)
+		val |= mask;
+	else
+		val &= ~mask;
+	__change_bit(endpoint_id, interrupt->suspend_enabled);
+
+	iowrite32(val, ipa->reg_virt + offset);
+
+	if (!weight && enable)
+		ipa_interrupt_enable(ipa, IPA_IRQ_TX_SUSPEND);
+}
+
+/* Enable TX_SUSPEND for an endpoint */
+void
+ipa_interrupt_suspend_enable(struct ipa_interrupt *interrupt, u32 endpoint_id)
+{
+	ipa_interrupt_suspend_control(interrupt, endpoint_id, true);
+}
+
+/* Disable TX_SUSPEND for an endpoint */
+void
+ipa_interrupt_suspend_disable(struct ipa_interrupt *interrupt, u32 endpoint_id)
+{
+	ipa_interrupt_suspend_control(interrupt, endpoint_id, false);
+}
+
+/* Simulate arrival of an IPA TX_SUSPEND interrupt */
+void ipa_interrupt_simulate_suspend(struct ipa_interrupt *interrupt)
+{
+	ipa_interrupt_process(interrupt, IPA_IRQ_TX_SUSPEND);
+}
+
+/* Configure the IPA interrupt framework */
+int ipa_interrupt_config(struct ipa *ipa)
+{
+	struct ipa_interrupt *interrupt = ipa->interrupt;
+	unsigned int irq = interrupt->irq;
+	struct device *dev = ipa->dev;
+	const struct reg *reg;
+	int ret;
+
+	interrupt->ipa = ipa;
+
+	/* Initially all IPA interrupt types are disabled */
+	interrupt->enabled = 0;
+	interrupt->suspend_enabled = bitmap_zalloc(ipa->endpoint_count,
+						   GFP_KERNEL);
+	if (!interrupt->suspend_enabled) {
+		ret = -ENOMEM;
+		goto err_kfree;
+	}
+
+	/* Disable IPA interrupt types */
+	reg = ipa_reg(ipa, IPA_IRQ_EN);
+	iowrite32(0, ipa->reg_virt + reg_offset(reg));
+
+	ret = request_threaded_irq(irq, NULL, ipa_isr_thread, IRQF_ONESHOT,
+				   "ipa", interrupt);
+	if (ret) {
+		dev_err(dev, "error %d requesting \"ipa\" IRQ\n", ret);
+		goto err_free_bitmap;
+	}
+
+	ret = device_init_wakeup(dev, true);
+	if (ret) {
+		dev_err(dev, "error %d enabling wakeup\n", ret);
+		goto err_free_irq;
+	}
+
+	ret = dev_pm_set_wake_irq(dev, irq);
+	if (ret) {
+		dev_err(dev, "error %d registering \"ipa\" IRQ as wakeirq\n",
+			ret);
+		goto err_disable_wakeup;
+	}
+
+	ipa->interrupt = interrupt;
+
+	return 0;
+
+err_disable_wakeup:
+	(void)device_init_wakeup(dev, false);
+err_free_irq:
+	free_irq(interrupt->irq, interrupt);
+err_free_bitmap:
+	bitmap_free(interrupt->suspend_enabled);
+err_kfree:
+	kfree(interrupt);
+
+	return ret;
+}
+
+/* Inverse of ipa_interrupt_config() */
+void ipa_interrupt_deconfig(struct ipa *ipa)
+{
+	struct ipa_interrupt *interrupt = ipa->interrupt;
+	struct device *dev = ipa->dev;
+
+	ipa->interrupt = NULL;
+
+	dev_pm_clear_wake_irq(dev);
+	(void)device_init_wakeup(dev, false);
+	free_irq(interrupt->irq, interrupt);
+	bitmap_free(interrupt->suspend_enabled);
+}
+
+/* Initialize the IPA interrupt structure */
+struct ipa_interrupt *ipa_interrupt_init(struct platform_device *pdev)
+{
+	struct ipa_interrupt *interrupt;
+	int irq;
+
+	irq = platform_get_irq_byname(pdev, "ipa");
+	if (irq <= 0)
+		return ERR_PTR(irq ? : -EINVAL);
+
+	interrupt = kzalloc(sizeof(*interrupt), GFP_KERNEL);
+	if (!interrupt)
+		return ERR_PTR(-ENOMEM);
+	interrupt->irq = irq;
+
+	return interrupt;
+}
+
+/* Inverse of ipa_interrupt_init() */
+void ipa_interrupt_exit(struct ipa_interrupt *interrupt)
+{
+	kfree(interrupt);
+}