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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Gasket common interrupt module. Defines functions for enabling
* eventfd-triggered interrupts between a Gasket device and a host process.
*
* Copyright (C) 2018 Google, Inc.
*/
#ifndef __GASKET_INTERRUPT_H__
#define __GASKET_INTERRUPT_H__
#include <linux/eventfd.h>
#include <linux/pci.h>
#include "gasket_core.h"
/* Note that this currently assumes that device interrupts are a dense set,
* numbered from 0 - (num_interrupts - 1). Should this have to change, these
* APIs will have to be updated.
*/
/* Opaque type used to hold interrupt subsystem data. */
struct gasket_interrupt_data;
/*
* Initialize the interrupt module.
* @gasket_dev: The Gasket device structure for the device to be initted.
* @type: Type of the interrupt. (See gasket_interrupt_type).
* @name: The name to associate with these interrupts.
* @interrupts: An array of all interrupt descriptions for this device.
* @num_interrupts: The length of the @interrupts array.
* @pack_width: The width, in bits, of a single field in a packed interrupt reg.
* @bar_index: The bar containing all interrupt registers.
*
* Allocates and initializes data to track interrupt state for a device.
* After this call, no interrupts will be configured/delivered; call
* gasket_interrupt_set_vector[_packed] to associate each interrupt with an
* __iomem location, then gasket_interrupt_set_eventfd to associate an eventfd
* with an interrupt.
*
* If num_interrupts interrupts are not available, this call will return a
* negative error code. In that case, gasket_interrupt_cleanup should still be
* called. Returns 0 on success (which can include a device where interrupts
* are not possible to set up, but is otherwise OK; that device will report
* status LAMED.)
*/
int gasket_interrupt_init(
struct gasket_dev *gasket_dev, const char *name, int type,
const struct gasket_interrupt_desc *interrupts,
int num_interrupts, int pack_width, int bar_index,
const struct gasket_wire_interrupt_offsets *wire_int_offsets);
/*
* Clean up a device's interrupt structure.
* @gasket_dev: The Gasket information structure for this device.
*
* Cleans up the device's interrupts and deallocates data.
*/
void gasket_interrupt_cleanup(struct gasket_dev *gasket_dev);
/*
* Clean up and re-initialize the MSI-x subsystem.
* @gasket_dev: The Gasket information structure for this device.
*
* Performs a teardown of the MSI-x subsystem and re-initializes it. Does not
* free the underlying data structures. Returns 0 on success and an error code
* on error.
*/
int gasket_interrupt_reinit(struct gasket_dev *gasket_dev);
/*
* Reset the counts stored in the interrupt subsystem.
* @gasket_dev: The Gasket information structure for this device.
*
* Sets the counts of all interrupts in the subsystem to 0.
*/
int gasket_interrupt_reset_counts(struct gasket_dev *gasket_dev);
/*
* Associates an eventfd with a device interrupt.
* @data: Pointer to device interrupt data.
* @interrupt: The device interrupt to configure.
* @event_fd: The eventfd to associate with the interrupt.
*
* Prepares the host to receive notification of device interrupts by associating
* event_fd with interrupt. Upon receipt of a device interrupt, event_fd will be
* signaled, after successful configuration.
*
* Returns 0 on success, a negative error code otherwise.
*/
int gasket_interrupt_set_eventfd(
struct gasket_interrupt_data *interrupt_data, int interrupt,
int event_fd);
/*
* Removes an interrupt-eventfd association.
* @data: Pointer to device interrupt data.
* @interrupt: The device interrupt to de-associate.
*
* Removes any eventfd associated with the specified interrupt, if any.
*/
int gasket_interrupt_clear_eventfd(
struct gasket_interrupt_data *interrupt_data, int interrupt);
/*
* Signals the eventfd associated with interrupt.
* @data: Pointer to device interrupt data.
* @interrupt: The device interrupt to signal for.
*
* Simulates a device interrupt by signaling the eventfd associated with
* interrupt, if any.
* Returns 0 if the eventfd was successfully triggered, a negative error code
* otherwise (if, for example, no eventfd was associated with interrupt).
*/
int gasket_interrupt_trigger_eventfd(
struct gasket_interrupt_data *interrupt_data, int interrupt);
/*
* The below functions exist for backwards compatibility.
* No new uses should be written.
*/
/*
* Retrieve a pointer to data's MSI-X
* entries.
* @data: The interrupt data from which to extract.
*
* Returns the internal pointer to data's MSI-X entries.
*/
struct msix_entry *gasket_interrupt_get_msix_entries(
struct gasket_interrupt_data *interrupt_data);
/*
* Get the health of the interrupt subsystem.
* @gasket_dev: The Gasket device struct.
*
* Returns DEAD if not set up, LAMED if initialization failed, and ALIVE
* otherwise.
*/
int gasket_interrupt_system_status(struct gasket_dev *gasket_dev);
#endif
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