include/linux/msi.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef LINUX_MSI_H
#define LINUX_MSI_H

/*
 * This header file contains MSI data structures and functions which are
 * only relevant for:
 *	- Interrupt core code
 *	- PCI/MSI core code
 *	- MSI interrupt domain implementations
 *	- IOMMU, low level VFIO, NTB and other justified exceptions
 *	  dealing with low level MSI details.
 *
 * Regular device drivers have no business with any of these functions and
 * especially storing MSI descriptor pointers in random code is considered
 * abuse. The only function which is relevant for drivers is msi_get_virq().
 */

#include <linux/cpumask.h>
#include <linux/xarray.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <asm/msi.h>

/* Dummy shadow structures if an architecture does not define them */
#ifndef arch_msi_msg_addr_lo
typedef struct arch_msi_msg_addr_lo {
	u32	address_lo;
} __attribute__ ((packed)) arch_msi_msg_addr_lo_t;
#endif

#ifndef arch_msi_msg_addr_hi
typedef struct arch_msi_msg_addr_hi {
	u32	address_hi;
} __attribute__ ((packed)) arch_msi_msg_addr_hi_t;
#endif

#ifndef arch_msi_msg_data
typedef struct arch_msi_msg_data {
	u32	data;
} __attribute__ ((packed)) arch_msi_msg_data_t;
#endif

/**
 * msi_msg - Representation of a MSI message
 * @address_lo:		Low 32 bits of msi message address
 * @arch_addrlo:	Architecture specific shadow of @address_lo
 * @address_hi:		High 32 bits of msi message address
 *			(only used when device supports it)
 * @arch_addrhi:	Architecture specific shadow of @address_hi
 * @data:		MSI message data (usually 16 bits)
 * @arch_data:		Architecture specific shadow of @data
 */
struct msi_msg {
	union {
		u32			address_lo;
		arch_msi_msg_addr_lo_t	arch_addr_lo;
	};
	union {
		u32			address_hi;
		arch_msi_msg_addr_hi_t	arch_addr_hi;
	};
	union {
		u32			data;
		arch_msi_msg_data_t	arch_data;
	};
};

extern int pci_msi_ignore_mask;
/* Helper functions */
struct irq_data;
struct msi_desc;
struct pci_dev;
struct platform_msi_priv_data;
struct device_attribute;

void __get_cached_msi_msg(struct msi_desc *entry, struct msi_msg *msg);
#ifdef CONFIG_GENERIC_MSI_IRQ
void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg);
#else
static inline void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg)
{
}
#endif

typedef void (*irq_write_msi_msg_t)(struct msi_desc *desc,
				    struct msi_msg *msg);

/**
 * pci_msi_desc - PCI/MSI specific MSI descriptor data
 *
 * @msi_mask:	[PCI MSI]   MSI cached mask bits
 * @msix_ctrl:	[PCI MSI-X] MSI-X cached per vector control bits
 * @is_msix:	[PCI MSI/X] True if MSI-X
 * @multiple:	[PCI MSI/X] log2 num of messages allocated
 * @multi_cap:	[PCI MSI/X] log2 num of messages supported
 * @can_mask:	[PCI MSI/X] Masking supported?
 * @is_64:	[PCI MSI/X] Address size: 0=32bit 1=64bit
 * @default_irq:[PCI MSI/X] The default pre-assigned non-MSI irq
 * @mask_pos:	[PCI MSI]   Mask register position
 * @mask_base:	[PCI MSI-X] Mask register base address
 */
struct pci_msi_desc {
	union {
		u32 msi_mask;
		u32 msix_ctrl;
	};
	struct {
		u8	is_msix		: 1;
		u8	multiple	: 3;
		u8	multi_cap	: 3;
		u8	can_mask	: 1;
		u8	is_64		: 1;
		u8	is_virtual	: 1;
		unsigned default_irq;
	} msi_attrib;
	union {
		u8	mask_pos;
		void __iomem *mask_base;
	};
};

#define MSI_MAX_INDEX		((unsigned int)USHRT_MAX)

/**
 * struct msi_desc - Descriptor structure for MSI based interrupts
 * @irq:	The base interrupt number
 * @nvec_used:	The number of vectors used
 * @dev:	Pointer to the device which uses this descriptor
 * @msg:	The last set MSI message cached for reuse
 * @affinity:	Optional pointer to a cpu affinity mask for this descriptor
 * @iommu_msi_iova: Optional shifted IOVA from the IOMMU to override the msi_addr.
 *                  Only used if iommu_msi_shift != 0
 * @iommu_msi_shift: Indicates how many bits of the original address should be
 *                   preserved when using iommu_msi_iova.
 * @sysfs_attr:	Pointer to sysfs device attribute
 *
 * @write_msi_msg:	Callback that may be called when the MSI message
 *			address or data changes
 * @write_msi_msg_data:	Data parameter for the callback.
 *
 * @msi_index:	Index of the msi descriptor
 * @pci:	PCI specific msi descriptor data
 */
struct msi_desc {
	/* Shared device/bus type independent data */
	unsigned int			irq;
	unsigned int			nvec_used;
	struct device			*dev;
	struct msi_msg			msg;
	struct irq_affinity_desc	*affinity;
#ifdef CONFIG_IRQ_MSI_IOMMU
	u64				iommu_msi_iova : 58;
	u64				iommu_msi_shift : 6;
#endif
#ifdef CONFIG_SYSFS
	struct device_attribute		*sysfs_attrs;
#endif

	void (*write_msi_msg)(struct msi_desc *entry, void *data);
	void *write_msi_msg_data;

	u16				msi_index;
	struct pci_msi_desc		pci;
};

/*
 * Filter values for the MSI descriptor iterators and accessor functions.
 */
enum msi_desc_filter {
	/* All descriptors */
	MSI_DESC_ALL,
	/* Descriptors which have no interrupt associated */
	MSI_DESC_NOTASSOCIATED,
	/* Descriptors which have an interrupt associated */
	MSI_DESC_ASSOCIATED,
};

/**
 * msi_device_data - MSI per device data
 * @properties:		MSI properties which are interesting to drivers
 * @platform_data:	Platform-MSI specific data
 * @mutex:		Mutex protecting the MSI descriptor store
 * @__store:		Xarray for storing MSI descriptor pointers
 * @__iter_idx:		Index to search the next entry for iterators
 */
struct msi_device_data {
	unsigned long			properties;
	struct platform_msi_priv_data	*platform_data;
	struct mutex			mutex;
	struct xarray			__store;
	unsigned long			__iter_idx;
};

int msi_setup_device_data(struct device *dev);

unsigned int msi_get_virq(struct device *dev, unsigned int index);
void msi_lock_descs(struct device *dev);
void msi_unlock_descs(struct device *dev);

struct msi_desc *msi_first_desc(struct device *dev, enum msi_desc_filter filter);
struct msi_desc *msi_next_desc(struct device *dev, enum msi_desc_filter filter);

/**
 * msi_for_each_desc - Iterate the MSI descriptors
 *
 * @desc:	struct msi_desc pointer used as iterator
 * @dev:	struct device pointer - device to iterate
 * @filter:	Filter for descriptor selection
 *
 * Notes:
 *  - The loop must be protected with a msi_lock_descs()/msi_unlock_descs()
 *    pair.
 *  - It is safe to remove a retrieved MSI descriptor in the loop.
 */
#define msi_for_each_desc(desc, dev, filter)			\
	for ((desc) = msi_first_desc((dev), (filter)); (desc);	\
	     (desc) = msi_next_desc((dev), (filter)))

#define msi_desc_to_dev(desc)		((desc)->dev)

static inline void msi_desc_set_iommu_msi_iova(struct msi_desc *desc, u64 msi_iova,
					       unsigned int msi_shift)
{
#ifdef CONFIG_IRQ_MSI_IOMMU
	desc->iommu_msi_iova = msi_iova >> msi_shift;
	desc->iommu_msi_shift = msi_shift;
#endif
}

#ifdef CONFIG_PCI_MSI
struct pci_dev *msi_desc_to_pci_dev(struct msi_desc *desc);
void pci_write_msi_msg(unsigned int irq, struct msi_msg *msg);
#else /* CONFIG_PCI_MSI */
static inline void pci_write_msi_msg(unsigned int irq, struct msi_msg *msg)
{
}
#endif /* CONFIG_PCI_MSI */

int msi_add_msi_desc(struct device *dev, struct msi_desc *init_desc);
void msi_free_msi_descs_range(struct device *dev, enum msi_desc_filter filter,
			      unsigned int first_index, unsigned int last_index);

/**
 * msi_free_msi_descs - Free MSI descriptors of a device
 * @dev:	Device to free the descriptors
 */
static inline void msi_free_msi_descs(struct device *dev)
{
	msi_free_msi_descs_range(dev, MSI_DESC_ALL, 0, MSI_MAX_INDEX);
}

void __pci_read_msi_msg(struct msi_desc *entry, struct msi_msg *msg);
void __pci_write_msi_msg(struct msi_desc *entry, struct msi_msg *msg);

void pci_msi_mask_irq(struct irq_data *data);
void pci_msi_unmask_irq(struct irq_data *data);

/*
 * The arch hooks to setup up msi irqs. Default functions are implemented
 * as weak symbols so that they /can/ be overriden by architecture specific
 * code if needed. These hooks can only be enabled by the architecture.
 *
 * If CONFIG_PCI_MSI_ARCH_FALLBACKS is not selected they are replaced by
 * stubs with warnings.
 */
#ifdef CONFIG_PCI_MSI_ARCH_FALLBACKS
int arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc);
void arch_teardown_msi_irq(unsigned int irq);
int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type);
void arch_teardown_msi_irqs(struct pci_dev *dev);
#endif /* CONFIG_PCI_MSI_ARCH_FALLBACKS */

/*
 * Xen uses non-default msi_domain_ops and hence needs a way to populate sysfs
 * entries of MSI IRQs.
 */
#if defined(CONFIG_PCI_XEN) || defined(CONFIG_PCI_MSI_ARCH_FALLBACKS)
#ifdef CONFIG_SYSFS
int msi_device_populate_sysfs(struct device *dev);
void msi_device_destroy_sysfs(struct device *dev);
#else /* CONFIG_SYSFS */
static inline int msi_device_populate_sysfs(struct device *dev) { return 0; }
static inline void msi_device_destroy_sysfs(struct device *dev) { }
#endif /* !CONFIG_SYSFS */
#endif /* CONFIG_PCI_XEN || CONFIG_PCI_MSI_ARCH_FALLBACKS */

/*
 * The restore hook is still available even for fully irq domain based
 * setups. Courtesy to XEN/X86.
 */
bool arch_restore_msi_irqs(struct pci_dev *dev);

#ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN

#include <linux/irqhandler.h>

struct irq_domain;
struct irq_domain_ops;
struct irq_chip;
struct device_node;
struct fwnode_handle;
struct msi_domain_info;

/**
 * struct msi_domain_ops - MSI interrupt domain callbacks
 * @get_hwirq:		Retrieve the resulting hw irq number
 * @msi_init:		Domain specific init function for MSI interrupts
 * @msi_free:		Domain specific function to free a MSI interrupts
 * @msi_check:		Callback for verification of the domain/info/dev data
 * @msi_prepare:	Prepare the allocation of the interrupts in the domain
 * @set_desc:		Set the msi descriptor for an interrupt
 * @domain_alloc_irqs:	Optional function to override the default allocation
 *			function.
 * @domain_free_irqs:	Optional function to override the default free
 *			function.
 *
 * @get_hwirq, @msi_init and @msi_free are callbacks used by the underlying
 * irqdomain.
 *
 * @msi_check, @msi_prepare and @set_desc are callbacks used by
 * msi_domain_alloc/free_irqs().
 *
 * @domain_alloc_irqs, @domain_free_irqs can be used to override the
 * default allocation/free functions (__msi_domain_alloc/free_irqs). This
 * is initially for a wrapper around XENs seperate MSI universe which can't
 * be wrapped into the regular irq domains concepts by mere mortals.  This
 * allows to universally use msi_domain_alloc/free_irqs without having to
 * special case XEN all over the place.
 *
 * Contrary to other operations @domain_alloc_irqs and @domain_free_irqs
 * are set to the default implementation if NULL and even when
 * MSI_FLAG_USE_DEF_DOM_OPS is not set to avoid breaking existing users and
 * because these callbacks are obviously mandatory.
 *
 * This is NOT meant to be abused, but it can be useful to build wrappers
 * for specialized MSI irq domains which need extra work before and after
 * calling __msi_domain_alloc_irqs()/__msi_domain_free_irqs().
 */
struct msi_domain_ops {
	irq_hw_number_t	(*get_hwirq)(struct msi_domain_info *info,
				     msi_alloc_info_t *arg);
	int		(*msi_init)(struct irq_domain *domain,
				    struct msi_domain_info *info,
				    unsigned int virq, irq_hw_number_t hwirq,
				    msi_alloc_info_t *arg);
	void		(*msi_free)(struct irq_domain *domain,
				    struct msi_domain_info *info,
				    unsigned int virq);
	int		(*msi_check)(struct irq_domain *domain,
				     struct msi_domain_info *info,
				     struct device *dev);
	int		(*msi_prepare)(struct irq_domain *domain,
				       struct device *dev, int nvec,
				       msi_alloc_info_t *arg);
	void		(*set_desc)(msi_alloc_info_t *arg,
				    struct msi_desc *desc);
	int		(*domain_alloc_irqs)(struct irq_domain *domain,
					     struct device *dev, int nvec);
	void		(*domain_free_irqs)(struct irq_domain *domain,
					    struct device *dev);
};

/**
 * struct msi_domain_info - MSI interrupt domain data
 * @flags:		Flags to decribe features and capabilities
 * @ops:		The callback data structure
 * @chip:		Optional: associated interrupt chip
 * @chip_data:		Optional: associated interrupt chip data
 * @handler:		Optional: associated interrupt flow handler
 * @handler_data:	Optional: associated interrupt flow handler data
 * @handler_name:	Optional: associated interrupt flow handler name
 * @data:		Optional: domain specific data
 */
struct msi_domain_info {
	u32			flags;
	struct msi_domain_ops	*ops;
	struct irq_chip		*chip;
	void			*chip_data;
	irq_flow_handler_t	handler;
	void			*handler_data;
	const char		*handler_name;
	void			*data;
};

/* Flags for msi_domain_info */
enum {
	/*
	 * Init non implemented ops callbacks with default MSI domain
	 * callbacks.
	 */
	MSI_FLAG_USE_DEF_DOM_OPS	= (1 << 0),
	/*
	 * Init non implemented chip callbacks with default MSI chip
	 * callbacks.
	 */
	MSI_FLAG_USE_DEF_CHIP_OPS	= (1 << 1),
	/* Support multiple PCI MSI interrupts */
	MSI_FLAG_MULTI_PCI_MSI		= (1 << 2),
	/* Support PCI MSIX interrupts */
	MSI_FLAG_PCI_MSIX		= (1 << 3),
	/* Needs early activate, required for PCI */
	MSI_FLAG_ACTIVATE_EARLY		= (1 << 4),
	/*
	 * Must reactivate when irq is started even when
	 * MSI_FLAG_ACTIVATE_EARLY has been set.
	 */
	MSI_FLAG_MUST_REACTIVATE	= (1 << 5),
	/* Is level-triggered capable, using two messages */
	MSI_FLAG_LEVEL_CAPABLE		= (1 << 6),
	/* Populate sysfs on alloc() and destroy it on free() */
	MSI_FLAG_DEV_SYSFS		= (1 << 7),
	/* MSI-X entries must be contiguous */
	MSI_FLAG_MSIX_CONTIGUOUS	= (1 << 8),
	/* Allocate simple MSI descriptors */
	MSI_FLAG_ALLOC_SIMPLE_MSI_DESCS	= (1 << 9),
	/* Free MSI descriptors */
	MSI_FLAG_FREE_MSI_DESCS		= (1 << 10),
};

int msi_domain_set_affinity(struct irq_data *data, const struct cpumask *mask,
			    bool force);

struct irq_domain *msi_create_irq_domain(struct fwnode_handle *fwnode,
					 struct msi_domain_info *info,
					 struct irq_domain *parent);
int __msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
			    int nvec);
int msi_domain_alloc_irqs_descs_locked(struct irq_domain *domain, struct device *dev,
				       int nvec);
int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
			  int nvec);
void __msi_domain_free_irqs(struct irq_domain *domain, struct device *dev);
void msi_domain_free_irqs_descs_locked(struct irq_domain *domain, struct device *dev);
void msi_domain_free_irqs(struct irq_domain *domain, struct device *dev);
struct msi_domain_info *msi_get_domain_info(struct irq_domain *domain);

struct irq_domain *platform_msi_create_irq_domain(struct fwnode_handle *fwnode,
						  struct msi_domain_info *info,
						  struct irq_domain *parent);
int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec,
				   irq_write_msi_msg_t write_msi_msg);
void platform_msi_domain_free_irqs(struct device *dev);

/* When an MSI domain is used as an intermediate domain */
int msi_domain_prepare_irqs(struct irq_domain *domain, struct device *dev,
			    int nvec, msi_alloc_info_t *args);
int msi_domain_populate_irqs(struct irq_domain *domain, struct device *dev,
			     int virq, int nvec, msi_alloc_info_t *args);
struct irq_domain *
__platform_msi_create_device_domain(struct device *dev,
				    unsigned int nvec,
				    bool is_tree,
				    irq_write_msi_msg_t write_msi_msg,
				    const struct irq_domain_ops *ops,
				    void *host_data);

#define platform_msi_create_device_domain(dev, nvec, write, ops, data)	\
	__platform_msi_create_device_domain(dev, nvec, false, write, ops, data)
#define platform_msi_create_device_tree_domain(dev, nvec, write, ops, data) \
	__platform_msi_create_device_domain(dev, nvec, true, write, ops, data)

int platform_msi_device_domain_alloc(struct irq_domain *domain, unsigned int virq,
				     unsigned int nr_irqs);
void platform_msi_device_domain_free(struct irq_domain *domain, unsigned int virq,
				     unsigned int nvec);
void *platform_msi_get_host_data(struct irq_domain *domain);
#endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */

#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
struct irq_domain *pci_msi_create_irq_domain(struct fwnode_handle *fwnode,
					     struct msi_domain_info *info,
					     struct irq_domain *parent);
u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev);
struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev);
bool pci_dev_has_special_msi_domain(struct pci_dev *pdev);
#else
static inline struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev)
{
	return NULL;
}
#endif /* CONFIG_PCI_MSI_IRQ_DOMAIN */

#endif /* LINUX_MSI_H */