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-rw-r--r--include/misc/cxl.h203
1 files changed, 203 insertions, 0 deletions
diff --git a/include/misc/cxl.h b/include/misc/cxl.h
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+/*
+ * Copyright 2015 IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#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);
+
+/* Get the physical device (ie. the PCIe card) which the AFU is attached */
+struct device *cxl_get_phys_dev(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);
+
+/*
+ * 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);
+unsigned int 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);
+
+#endif /* _MISC_CXL_H */

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