alistair23-linux/drivers/net/ipa/ipa_interrupt.c
Alex Elder ba764c4dad soc: qcom: ipa: clocking, interrupts, and memory
This patch incorporates three source files (and their headers).  They're
grouped into one patch mainly for the purpose of making the number and
size of patches in this series somewhat reasonable.

  - "ipa_clock.c" and "ipa_clock.h" implement clocking for the IPA device.
    The IPA has a single core clock managed by the common clock framework.
    In addition, the IPA has three buses whose bandwidth is managed by the
    Linux interconnect framework.  At this time the core clock and all
    three buses are either on or off; we don't yet do any more fine-grained
    management than that.  The core clock and interconnects are enabled
    and disabled as a unit, using a unified clock-like abstraction,
    ipa_clock_get()/ipa_clock_put().

  - "ipa_interrupt.c" and "ipa_interrupt.h" implement IPA interrupts.
    There are two hardware IRQs used by the IPA driver (the other is
    the GSI interrupt, described in a separate patch).  Several types
    of interrupt are handled by the IPA IRQ handler; these are not part
    of data/fast path.

  - The IPA has a region of local memory that is accessible by the AP
    (and modem).  Within that region are areas with certain defined
    purposes.  "ipa_mem.c" and "ipa_mem.h" define those regions, and
    implement their initialization.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-08 22:07:09 -07:00

254 lines
7.1 KiB
C

// 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);
}