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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2014-2018, The Linux Foundation. All rights reserved.
* Copyright (C) 2018-2020 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/types.h>
#include <linux/interrupt.h>
#include "ipa.h"
#include "ipa_clock.h"
#include "ipa_reg.h"
#include "ipa_endpoint.h"
#include "ipa_interrupt.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
* @handler: Array of handlers indexed by IPA interrupt ID
*/
struct ipa_interrupt {
struct ipa *ipa;
u32 irq;
u32 enabled;
ipa_irq_handler_t handler[IPA_IRQ_COUNT];
};
/* Returns true if the interrupt type is associated with the microcontroller */
static bool ipa_interrupt_uc(struct ipa_interrupt *interrupt, u32 irq_id)
{
return irq_id == IPA_IRQ_UC_0 || irq_id == IPA_IRQ_UC_1;
}
/* Process a particular interrupt type that has been received */
static void ipa_interrupt_process(struct ipa_interrupt *interrupt, u32 irq_id)
{
bool uc_irq = ipa_interrupt_uc(interrupt, irq_id);
struct ipa *ipa = interrupt->ipa;
u32 mask = BIT(irq_id);
/* For microcontroller interrupts, clear the interrupt right away,
* "to avoid clearing unhandled interrupts."
*/
if (uc_irq)
iowrite32(mask, ipa->reg_virt + IPA_REG_IRQ_CLR_OFFSET);
if (irq_id < IPA_IRQ_COUNT && interrupt->handler[irq_id])
interrupt->handler[irq_id](interrupt->ipa, irq_id);
/* 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.
*/
if (!uc_irq)
iowrite32(mask, ipa->reg_virt + IPA_REG_IRQ_CLR_OFFSET);
}
/* Process all IPA interrupt types that have been signaled */
static void ipa_interrupt_process_all(struct ipa_interrupt *interrupt)
{
struct ipa *ipa = interrupt->ipa;
u32 enabled = interrupt->enabled;
u32 mask;
/* The status register indicates which conditions are present,
* including conditions whose interrupt is not enabled. Handle
* only the enabled ones.
*/
mask = ioread32(ipa->reg_virt + IPA_REG_IRQ_STTS_OFFSET);
while ((mask &= enabled)) {
do {
u32 irq_id = __ffs(mask);
mask ^= BIT(irq_id);
ipa_interrupt_process(interrupt, irq_id);
} while (mask);
mask = ioread32(ipa->reg_virt + IPA_REG_IRQ_STTS_OFFSET);
}
}
/* Threaded part of the IPA IRQ handler */
static irqreturn_t ipa_isr_thread(int irq, void *dev_id)
{
struct ipa_interrupt *interrupt = dev_id;
ipa_clock_get(interrupt->ipa);
ipa_interrupt_process_all(interrupt);
ipa_clock_put(interrupt->ipa);
return IRQ_HANDLED;
}
/* Hard part (i.e., "real" IRQ handler) of the IRQ handler */
static irqreturn_t ipa_isr(int irq, void *dev_id)
{
struct ipa_interrupt *interrupt = dev_id;
struct ipa *ipa = interrupt->ipa;
u32 mask;
mask = ioread32(ipa->reg_virt + IPA_REG_IRQ_STTS_OFFSET);
if (mask & interrupt->enabled)
return IRQ_WAKE_THREAD;
/* Nothing in the mask was supposed to cause an interrupt */
iowrite32(mask, ipa->reg_virt + IPA_REG_IRQ_CLR_OFFSET);
dev_err(&ipa->pdev->dev, "%s: unexpected interrupt, mask 0x%08x\n",
__func__, mask);
return IRQ_HANDLED;
}
/* 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);
u32 val;
/* assert(mask & ipa->available); */
val = ioread32(ipa->reg_virt + IPA_REG_SUSPEND_IRQ_EN_OFFSET);
if (enable)
val |= mask;
else
val &= ~mask;
iowrite32(val, ipa->reg_virt + IPA_REG_SUSPEND_IRQ_EN_OFFSET);
}
/* 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);
}
/* Clear the suspend interrupt for all endpoints that signaled it */
void ipa_interrupt_suspend_clear_all(struct ipa_interrupt *interrupt)
{
struct ipa *ipa = interrupt->ipa;
u32 val;
val = ioread32(ipa->reg_virt + IPA_REG_IRQ_SUSPEND_INFO_OFFSET);
iowrite32(val, ipa->reg_virt + IPA_REG_SUSPEND_IRQ_CLR_OFFSET);
}
/* 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);
}
/* Add a handler for an IPA interrupt */
void ipa_interrupt_add(struct ipa_interrupt *interrupt,
enum ipa_irq_id ipa_irq, ipa_irq_handler_t handler)
{
struct ipa *ipa = interrupt->ipa;
/* assert(ipa_irq < IPA_IRQ_COUNT); */
interrupt->handler[ipa_irq] = handler;
/* Update the IPA interrupt mask to enable it */
interrupt->enabled |= BIT(ipa_irq);
iowrite32(interrupt->enabled, ipa->reg_virt + IPA_REG_IRQ_EN_OFFSET);
}
/* Remove the handler for an IPA interrupt type */
void
ipa_interrupt_remove(struct ipa_interrupt *interrupt, enum ipa_irq_id ipa_irq)
{
struct ipa *ipa = interrupt->ipa;
/* assert(ipa_irq < IPA_IRQ_COUNT); */
/* Update the IPA interrupt mask to disable it */
interrupt->enabled &= ~BIT(ipa_irq);
iowrite32(interrupt->enabled, ipa->reg_virt + IPA_REG_IRQ_EN_OFFSET);
interrupt->handler[ipa_irq] = NULL;
}
/* Set up the IPA interrupt framework */
struct ipa_interrupt *ipa_interrupt_setup(struct ipa *ipa)
{
struct device *dev = &ipa->pdev->dev;
struct ipa_interrupt *interrupt;
unsigned int irq;
int ret;
ret = platform_get_irq_byname(ipa->pdev, "ipa");
if (ret <= 0) {
dev_err(dev, "DT error %d getting \"ipa\" IRQ property\n",
ret);
return ERR_PTR(ret ? : -EINVAL);
}
irq = ret;
interrupt = kzalloc(sizeof(*interrupt), GFP_KERNEL);
if (!interrupt)
return ERR_PTR(-ENOMEM);
interrupt->ipa = ipa;
interrupt->irq = irq;
/* Start with all IPA interrupts disabled */
iowrite32(0, ipa->reg_virt + IPA_REG_IRQ_EN_OFFSET);
ret = request_threaded_irq(irq, ipa_isr, ipa_isr_thread, IRQF_ONESHOT,
"ipa", interrupt);
if (ret) {
dev_err(dev, "error %d requesting \"ipa\" IRQ\n", ret);
goto err_kfree;
}
return interrupt;
err_kfree:
kfree(interrupt);
return ERR_PTR(ret);
}
/* Tear down the IPA interrupt framework */
void ipa_interrupt_teardown(struct ipa_interrupt *interrupt)
{
free_irq(interrupt->irq, interrupt);
kfree(interrupt);
}
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