linux/include/misc/cxl.h

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright 2015 IBM Corp.
*/
#ifndef _MISC_CXL_H
#define _MISC_CXL_H
#include <linux/pci.h>
#include <linux/poll.h>
#include <linux/interrupt.h>
#include <uapi/misc/cxl.h>
/*
* This documents the in kernel API for driver to use CXL. It allows kernel
* drivers to bind to AFUs using an AFU configuration record exposed as a PCI
* configuration record.
*
* This API enables control over AFU and contexts which can't be part of the
* generic PCI API. This API is agnostic to the actual AFU.
*/
/* Get the AFU associated with a pci_dev */
struct cxl_afu *cxl_pci_to_afu(struct pci_dev *dev);
/* Get the AFU conf record number associated with a pci_dev */
unsigned int cxl_pci_to_cfg_record(struct pci_dev *dev);
/*
* Context lifetime overview:
*
* An AFU context may be inited and then started and stoppped multiple times
* before it's released. ie.
* - cxl_dev_context_init()
* - cxl_start_context()
* - cxl_stop_context()
* - cxl_start_context()
* - cxl_stop_context()
* ...repeat...
* - cxl_release_context()
* Once released, a context can't be started again.
*
* One context is inited by the cxl driver for every pci_dev. This is to be
* used as a default kernel context. cxl_get_context() will get this
* context. This context will be released by PCI hot unplug, so doesn't need to
* be released explicitly by drivers.
*
* Additional kernel contexts may be inited using cxl_dev_context_init().
* These must be released using cxl_context_detach().
*
* Once a context has been inited, IRQs may be configured. Firstly these IRQs
* must be allocated (cxl_allocate_afu_irqs()), then individually mapped to
* specific handlers (cxl_map_afu_irq()).
*
* These IRQs can be unmapped (cxl_unmap_afu_irq()) and finally released
* (cxl_free_afu_irqs()).
*
* The AFU can be reset (cxl_afu_reset()). This will cause the PSL/AFU
* hardware to lose track of all contexts. It's upto the caller of
* cxl_afu_reset() to restart these contexts.
*/
/*
* On pci_enabled_device(), the cxl driver will init a single cxl context for
* use by the driver. It doesn't start this context (as that will likely
* generate DMA traffic for most AFUs).
*
* This gets the default context associated with this pci_dev. This context
* doesn't need to be released as this will be done by the PCI subsystem on hot
* unplug.
*/
struct cxl_context *cxl_get_context(struct pci_dev *dev);
/*
* Allocate and initalise a context associated with a AFU PCI device. This
* doesn't start the context in the AFU.
*/
struct cxl_context *cxl_dev_context_init(struct pci_dev *dev);
/*
* Release and free a context. Context should be stopped before calling.
*/
int cxl_release_context(struct cxl_context *ctx);
/*
* Set and get private data associated with a context. Allows drivers to have a
* back pointer to some useful structure.
*/
int cxl_set_priv(struct cxl_context *ctx, void *priv);
void *cxl_get_priv(struct cxl_context *ctx);
/*
* Allocate AFU interrupts for this context. num=0 will allocate the default
* for this AFU as given in the AFU descriptor. This number doesn't include the
* interrupt 0 (CAIA defines AFU IRQ 0 for page faults). Each interrupt to be
* used must map a handler with cxl_map_afu_irq.
*/
int cxl_allocate_afu_irqs(struct cxl_context *cxl, int num);
/* Free allocated interrupts */
void cxl_free_afu_irqs(struct cxl_context *cxl);
/*
* Map a handler for an AFU interrupt associated with a particular context. AFU
* IRQS numbers start from 1 (CAIA defines AFU IRQ 0 for page faults). cookie
* is private data is that will be provided to the interrupt handler.
*/
int cxl_map_afu_irq(struct cxl_context *cxl, int num,
irq_handler_t handler, void *cookie, char *name);
/* unmap mapped IRQ handlers */
void cxl_unmap_afu_irq(struct cxl_context *cxl, int num, void *cookie);
/*
* Start work on the AFU. This starts an cxl context and associates it with a
* task. task == NULL will make it a kernel context.
*/
int cxl_start_context(struct cxl_context *ctx, u64 wed,
struct task_struct *task);
/*
* Stop a context and remove it from the PSL
*/
int cxl_stop_context(struct cxl_context *ctx);
/* Reset the AFU */
int cxl_afu_reset(struct cxl_context *ctx);
/*
* Set a context as a master context.
* This sets the default problem space area mapped as the full space, rather
* than just the per context area (for slaves).
*/
void cxl_set_master(struct cxl_context *ctx);
/*
* Map and unmap the AFU Problem Space area. The amount and location mapped
* depends on if this context is a master or slave.
*/
void __iomem *cxl_psa_map(struct cxl_context *ctx);
void cxl_psa_unmap(void __iomem *addr);
/* Get the process element for this context */
int cxl_process_element(struct cxl_context *ctx);
/*
* These calls allow drivers to create their own file descriptors and make them
* identical to the cxl file descriptor user API. An example use case:
*
* struct file_operations cxl_my_fops = {};
* ......
* // Init the context
* ctx = cxl_dev_context_init(dev);
* if (IS_ERR(ctx))
* return PTR_ERR(ctx);
* // Create and attach a new file descriptor to my file ops
* file = cxl_get_fd(ctx, &cxl_my_fops, &fd);
* // Start context
* rc = cxl_start_work(ctx, &work.work);
* if (rc) {
* fput(file);
* put_unused_fd(fd);
* return -ENODEV;
* }
* // No error paths after installing the fd
* fd_install(fd, file);
* return fd;
*
* This inits a context, and gets a file descriptor and associates some file
* ops to that file descriptor. If the file ops are blank, the cxl driver will
* fill them in with the default ones that mimic the standard user API. Once
* completed, the file descriptor can be installed. Once the file descriptor is
* installed, it's visible to the user so no errors must occur past this point.
*
* If cxl_fd_release() file op call is installed, the context will be stopped
* and released when the fd is released. Hence the driver won't need to manage
* this itself.
*/
/*
* Take a context and associate it with my file ops. Returns the associated
* file and file descriptor. Any file ops which are blank are filled in by the
* cxl driver with the default ops to mimic the standard API.
*/
struct file *cxl_get_fd(struct cxl_context *ctx, struct file_operations *fops,
int *fd);
/* Get the context associated with this file */
struct cxl_context *cxl_fops_get_context(struct file *file);
/*
* Start a context associated a struct cxl_ioctl_start_work used by the
* standard cxl user API.
*/
int cxl_start_work(struct cxl_context *ctx,
struct cxl_ioctl_start_work *work);
/*
* Export all the existing fops so drivers can use them
*/
int cxl_fd_open(struct inode *inode, struct file *file);
int cxl_fd_release(struct inode *inode, struct file *file);
long cxl_fd_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
int cxl_fd_mmap(struct file *file, struct vm_area_struct *vm);
__poll_t cxl_fd_poll(struct file *file, struct poll_table_struct *poll);
ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count,
loff_t *off);
/*
* For EEH, a driver may want to assert a PERST will reload the same image
* from flash into the FPGA.
*
* This is a property of the entire adapter, not a single AFU, so drivers
* should set this property with care!
*/
void cxl_perst_reloads_same_image(struct cxl_afu *afu,
bool perst_reloads_same_image);
/*
* Read the VPD for the card where the AFU resides
*/
ssize_t cxl_read_adapter_vpd(struct pci_dev *dev, void *buf, size_t count);
cxl: Add mechanism for delivering AFU driver specific events This adds an afu_driver_ops structure with fetch_event() and event_delivered() callbacks. An AFU driver such as cxlflash can fill this out and associate it with a context to enable passing custom AFU specific events to userspace. This also adds a new kernel API function cxl_context_pending_events(), that the AFU driver can use to notify the cxl driver that new specific events are ready to be delivered, and wake up anyone waiting on the context wait queue. The current count of AFU driver specific events is stored in the field afu_driver_events of the context structure. The cxl driver checks the afu_driver_events count during poll, select, read, etc. calls to check if an AFU driver specific event is pending, and calls fetch_event() to obtain and deliver that event. This way, the cxl driver takes care of all the usual locking semantics around these calls and handles all the generic cxl events, so that the AFU driver only needs to worry about it's own events. fetch_event() return a struct cxl_event_afu_driver_reserved, allocated by the AFU driver, and filled in with the specific event information and size. Total event size (header + data) should not be greater than CXL_READ_MIN_SIZE (4K). Th cxl driver prepends an appropriate cxl event header, copies the event to userspace, and finally calls event_delivered() to return the status of the operation to the AFU driver. The event is identified by the context and cxl_event_afu_driver_reserved pointers. Since AFU drivers provide their own means for userspace to obtain the AFU file descriptor (i.e. cxlflash uses an ioctl on their scsi file descriptor to obtain the AFU file descriptor) and the generic cxl driver will never use this event, the ABI of the event is up to each individual AFU driver. Signed-off-by: Philippe Bergheaud <felix@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-06-23 21:03:53 +08:00
/*
* AFU driver ops allow an AFU driver to create their own events to pass to
* userspace through the file descriptor as a simpler alternative to overriding
* the read() and poll() calls that works with the generic cxl events. These
* events are given priority over the generic cxl events, so they will be
* delivered first if multiple types of events are pending.
*
* The AFU driver must call cxl_context_events_pending() to notify the cxl
* driver that new events are ready to be delivered for a specific context.
* cxl_context_events_pending() will adjust the current count of AFU driver
* events for this context, and wake up anyone waiting on the context wait
* queue.
*
* The cxl driver will then call fetch_event() to get a structure defining
* the size and address of the driver specific event data. The cxl driver
* will build a cxl header with type and process_element fields filled in,
* and header.size set to sizeof(struct cxl_event_header) + data_size.
* The total size of the event is limited to CXL_READ_MIN_SIZE (4K).
*
* fetch_event() is called with a spin lock held, so it must not sleep.
*
* The cxl driver will then deliver the event to userspace, and finally
* call event_delivered() to return the status of the operation, identified
* by cxl context and AFU driver event data pointers.
* 0 Success
* -EFAULT copy_to_user() has failed
* -EINVAL Event data pointer is NULL, or event size is greater than
* CXL_READ_MIN_SIZE.
*/
struct cxl_afu_driver_ops {
struct cxl_event_afu_driver_reserved *(*fetch_event) (
struct cxl_context *ctx);
void (*event_delivered) (struct cxl_context *ctx,
struct cxl_event_afu_driver_reserved *event,
int rc);
};
/*
* Associate the above driver ops with a specific context.
* Reset the current count of AFU driver events.
*/
void cxl_set_driver_ops(struct cxl_context *ctx,
struct cxl_afu_driver_ops *ops);
/* Notify cxl driver that new events are ready to be delivered for context */
void cxl_context_events_pending(struct cxl_context *ctx,
unsigned int new_events);
#endif /* _MISC_CXL_H */