cxl: Add AFU virtual PHB and kernel API

This patch does two things.

Firstly it presents the Accelerator Function Unit (AFUs) behind the POWER
Service Layer (PSL) as PCI devices on a virtual PCI Host Bridge (vPHB).  This
in in addition to the PSL being a PCI device itself.

As part of the Coherent Accelerator Interface Architecture (CAIA) AFUs can
provide an AFU configuration.  This AFU configuration recored is architected to
be the same as a PCI config space.

This patch sets discovers the AFU configuration records, provides AFU config
space read/write functions to these configuration records.  It then enumerates
the PCI bus.  It also hooks in PCI ops where appropriate.  It also destroys the
vPHB when the physical card is removed.

Secondly, it add an in kernel API for AFU to use CXL.  AFUs must present a
driver that firstly binds as a PCI device.  This PCI device can then be using
to do CXL specific operations (that can't sit in the PCI ops) using this API.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

drivers/misc/cxl/Makefile

@@ -1,5 +1,6 @@
 cxl-y				+= main.o file.o irq.o fault.o native.o
 cxl-y				+= context.o sysfs.o debugfs.o pci.o trace.o
+cxl-y				+= vphb.o api.o
 obj-$(CONFIG_CXL)		+= cxl.o
 obj-$(CONFIG_CXL_BASE)		+= base.o
 

drivers/misc/cxl/api.c

@@ -0,0 +1,331 @@
+/*
+ * Copyright 2014 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.
+ */
+
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/anon_inodes.h>
+#include <linux/file.h>
+#include <misc/cxl.h>
+
+#include "cxl.h"
+
+struct cxl_context *cxl_dev_context_init(struct pci_dev *dev)
+{
+	struct cxl_afu *afu;
+	struct cxl_context  *ctx;
+	int rc;
+
+	afu = cxl_pci_to_afu(dev);
+
+	ctx = cxl_context_alloc();
+	if (IS_ERR(ctx))
+		return ctx;
+
+	/* Make it a slave context.  We can promote it later? */
+	rc = cxl_context_init(ctx, afu, false, NULL);
+	if (rc) {
+		kfree(ctx);
+		return ERR_PTR(-ENOMEM);
+	}
+	cxl_assign_psn_space(ctx);
+
+	return ctx;
+}
+EXPORT_SYMBOL_GPL(cxl_dev_context_init);
+
+struct cxl_context *cxl_get_context(struct pci_dev *dev)
+{
+	return dev->dev.archdata.cxl_ctx;
+}
+EXPORT_SYMBOL_GPL(cxl_get_context);
+
+struct device *cxl_get_phys_dev(struct pci_dev *dev)
+{
+	struct cxl_afu *afu;
+
+	afu = cxl_pci_to_afu(dev);
+
+	return afu->adapter->dev.parent;
+}
+EXPORT_SYMBOL_GPL(cxl_get_phys_dev);
+
+int cxl_release_context(struct cxl_context *ctx)
+{
+	if (ctx->status != CLOSED)
+		return -EBUSY;
+
+	cxl_context_free(ctx);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cxl_release_context);
+
+int cxl_allocate_afu_irqs(struct cxl_context *ctx, int num)
+{
+	if (num == 0)
+		num = ctx->afu->pp_irqs;
+	return afu_allocate_irqs(ctx, num);
+}
+EXPORT_SYMBOL_GPL(cxl_allocate_afu_irqs);
+
+void cxl_free_afu_irqs(struct cxl_context *ctx)
+{
+	cxl_release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
+}
+EXPORT_SYMBOL_GPL(cxl_free_afu_irqs);
+
+static irq_hw_number_t cxl_find_afu_irq(struct cxl_context *ctx, int num)
+{
+	__u16 range;
+	int r;
+
+	WARN_ON(num == 0);
+
+	for (r = 0; r < CXL_IRQ_RANGES; r++) {
+		range = ctx->irqs.range[r];
+		if (num < range) {
+			return ctx->irqs.offset[r] + num;
+		}
+		num -= range;
+	}
+	return 0;
+}
+
+int cxl_map_afu_irq(struct cxl_context *ctx, int num,
+		    irq_handler_t handler, void *cookie, char *name)
+{
+	irq_hw_number_t hwirq;
+
+	/*
+	 * Find interrupt we are to register.
+	 */
+	hwirq = cxl_find_afu_irq(ctx, num);
+	if (!hwirq)
+		return -ENOENT;
+
+	return cxl_map_irq(ctx->afu->adapter, hwirq, handler, cookie, name);
+}
+EXPORT_SYMBOL_GPL(cxl_map_afu_irq);
+
+void cxl_unmap_afu_irq(struct cxl_context *ctx, int num, void *cookie)
+{
+	irq_hw_number_t hwirq;
+	unsigned int virq;
+
+	hwirq = cxl_find_afu_irq(ctx, num);
+	if (!hwirq)
+		return;
+
+	virq = irq_find_mapping(NULL, hwirq);
+	if (virq)
+		cxl_unmap_irq(virq, cookie);
+}
+EXPORT_SYMBOL_GPL(cxl_unmap_afu_irq);
+
+/*
+ * Start a context
+ * Code here similar to afu_ioctl_start_work().
+ */
+int cxl_start_context(struct cxl_context *ctx, u64 wed,
+		      struct task_struct *task)
+{
+	int rc = 0;
+	bool kernel = true;
+
+	pr_devel("%s: pe: %i\n", __func__, ctx->pe);
+
+	mutex_lock(&ctx->status_mutex);
+	if (ctx->status == STARTED)
+		goto out; /* already started */
+
+	if (task) {
+		ctx->pid = get_task_pid(task, PIDTYPE_PID);
+		get_pid(ctx->pid);
+		kernel = false;
+	}
+
+	cxl_ctx_get();
+
+	if ((rc = cxl_attach_process(ctx, kernel, wed , 0))) {
+		put_pid(ctx->pid);
+		cxl_ctx_put();
+		goto out;
+	}
+
+	ctx->status = STARTED;
+	get_device(&ctx->afu->dev);
+out:
+	mutex_unlock(&ctx->status_mutex);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(cxl_start_context);
+
+int cxl_process_element(struct cxl_context *ctx)
+{
+	return ctx->pe;
+}
+EXPORT_SYMBOL_GPL(cxl_process_element);
+
+/* Stop a context.  Returns 0 on success, otherwise -Errno */
+int cxl_stop_context(struct cxl_context *ctx)
+{
+	int rc;
+
+	rc = __detach_context(ctx);
+	if (!rc)
+		put_device(&ctx->afu->dev);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(cxl_stop_context);
+
+void cxl_set_master(struct cxl_context *ctx)
+{
+	ctx->master = true;
+	cxl_assign_psn_space(ctx);
+}
+EXPORT_SYMBOL_GPL(cxl_set_master);
+
+/* wrappers around afu_* file ops which are EXPORTED */
+int cxl_fd_open(struct inode *inode, struct file *file)
+{
+	return afu_open(inode, file);
+}
+EXPORT_SYMBOL_GPL(cxl_fd_open);
+int cxl_fd_release(struct inode *inode, struct file *file)
+{
+	return afu_release(inode, file);
+}
+EXPORT_SYMBOL_GPL(cxl_fd_release);
+long cxl_fd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	return afu_ioctl(file, cmd, arg);
+}
+EXPORT_SYMBOL_GPL(cxl_fd_ioctl);
+int cxl_fd_mmap(struct file *file, struct vm_area_struct *vm)
+{
+	return afu_mmap(file, vm);
+}
+EXPORT_SYMBOL_GPL(cxl_fd_mmap);
+unsigned int cxl_fd_poll(struct file *file, struct poll_table_struct *poll)
+{
+	return afu_poll(file, poll);
+}
+EXPORT_SYMBOL_GPL(cxl_fd_poll);
+ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count,
+			loff_t *off)
+{
+	return afu_read(file, buf, count, off);
+}
+EXPORT_SYMBOL_GPL(cxl_fd_read);
+
+#define PATCH_FOPS(NAME) if (!fops->NAME) fops->NAME = afu_fops.NAME
+
+/* Get a struct file and fd for a context and attach the ops */
+struct file *cxl_get_fd(struct cxl_context *ctx, struct file_operations *fops,
+			int *fd)
+{
+	struct file *file;
+	int rc, flags, fdtmp;
+
+	flags = O_RDWR | O_CLOEXEC;
+
+	/* This code is similar to anon_inode_getfd() */
+	rc = get_unused_fd_flags(flags);
+	if (rc < 0)
+		return ERR_PTR(rc);
+	fdtmp = rc;
+
+	/*
+	 * Patch the file ops.  Needs to be careful that this is rentrant safe.
+	 */
+	if (fops) {
+		PATCH_FOPS(open);
+		PATCH_FOPS(poll);
+		PATCH_FOPS(read);
+		PATCH_FOPS(release);
+		PATCH_FOPS(unlocked_ioctl);
+		PATCH_FOPS(compat_ioctl);
+		PATCH_FOPS(mmap);
+	} else /* use default ops */
+		fops = (struct file_operations *)&afu_fops;
+
+	file = anon_inode_getfile("cxl", fops, ctx, flags);
+	if (IS_ERR(file))
+		put_unused_fd(fdtmp);
+	*fd = fdtmp;
+	return file;
+}
+EXPORT_SYMBOL_GPL(cxl_get_fd);
+
+struct cxl_context *cxl_fops_get_context(struct file *file)
+{
+	return file->private_data;
+}
+EXPORT_SYMBOL_GPL(cxl_fops_get_context);
+
+int cxl_start_work(struct cxl_context *ctx,
+		   struct cxl_ioctl_start_work *work)
+{
+	int rc;
+
+	/* code taken from afu_ioctl_start_work */
+	if (!(work->flags & CXL_START_WORK_NUM_IRQS))
+		work->num_interrupts = ctx->afu->pp_irqs;
+	else if ((work->num_interrupts < ctx->afu->pp_irqs) ||
+		 (work->num_interrupts > ctx->afu->irqs_max)) {
+		return -EINVAL;
+	}
+
+	rc = afu_register_irqs(ctx, work->num_interrupts);
+	if (rc)
+		return rc;
+
+	rc = cxl_start_context(ctx, work->work_element_descriptor, current);
+	if (rc < 0) {
+		afu_release_irqs(ctx, ctx);
+		return rc;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cxl_start_work);
+
+void __iomem *cxl_psa_map(struct cxl_context *ctx)
+{
+	struct cxl_afu *afu = ctx->afu;
+	int rc;
+
+	rc = cxl_afu_check_and_enable(afu);
+	if (rc)
+		return NULL;
+
+	pr_devel("%s: psn_phys%llx size:%llx\n",
+		 __func__, afu->psn_phys, afu->adapter->ps_size);
+	return ioremap(ctx->psn_phys, ctx->psn_size);
+}
+EXPORT_SYMBOL_GPL(cxl_psa_map);
+
+void cxl_psa_unmap(void __iomem *addr)
+{
+	iounmap(addr);
+}
+EXPORT_SYMBOL_GPL(cxl_psa_unmap);
+
+int cxl_afu_reset(struct cxl_context *ctx)
+{
+	struct cxl_afu *afu = ctx->afu;
+	int rc;
+
+	rc = __cxl_afu_reset(afu);
+	if (rc)
+		return rc;
+
+	return cxl_afu_check_and_enable(afu);
+}
+EXPORT_SYMBOL_GPL(cxl_afu_reset);

drivers/misc/cxl/cxl.h

@@ -378,6 +378,9 @@ struct cxl_afu {
 	int spa_max_procs;
 	unsigned int psl_virq;
 
+	/* pointer to the vphb */
+	struct pci_controller *phb;
+
 	int pp_irqs;
 	int irqs_max;
 	int num_procs;
@@ -671,6 +674,8 @@ int cxl_afu_check_and_enable(struct cxl_afu *afu);
 int cxl_psl_purge(struct cxl_afu *afu);
 
 void cxl_stop_trace(struct cxl *cxl);
+int cxl_pci_vphb_add(struct cxl_afu *afu);
+void cxl_pci_vphb_remove(struct cxl_afu *afu);
 
 extern struct pci_driver cxl_pci_driver;
 int afu_allocate_irqs(struct cxl_context *ctx, u32 count);