[linux-2.6-block.git] / drivers / misc / ocxl / file.c

// SPDX-License-Identifier: GPL-2.0+
// Copyright 2017 IBM Corp.
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/sched/signal.h>
#include <linux/uaccess.h>
#include <uapi/misc/ocxl.h>
#include "ocxl_internal.h"


#define OCXL_NUM_MINORS 256 /* Total to reserve */

static dev_t ocxl_dev;
static struct class *ocxl_class;
static struct mutex minors_idr_lock;
static struct idr minors_idr;

static struct ocxl_afu *find_and_get_afu(dev_t devno)
{
	struct ocxl_afu *afu;
	int afu_minor;

	afu_minor = MINOR(devno);
	/*
	 * We don't declare an RCU critical section here, as our AFU
	 * is protected by a reference counter on the device. By the time the
	 * minor number of a device is removed from the idr, the ref count of
	 * the device is already at 0, so no user API will access that AFU and
	 * this function can't return it.
	 */
	afu = idr_find(&minors_idr, afu_minor);
	if (afu)
		ocxl_afu_get(afu);
	return afu;
}

static int allocate_afu_minor(struct ocxl_afu *afu)
{
	int minor;

	mutex_lock(&minors_idr_lock);
	minor = idr_alloc(&minors_idr, afu, 0, OCXL_NUM_MINORS, GFP_KERNEL);
	mutex_unlock(&minors_idr_lock);
	return minor;
}

static void free_afu_minor(struct ocxl_afu *afu)
{
	mutex_lock(&minors_idr_lock);
	idr_remove(&minors_idr, MINOR(afu->dev.devt));
	mutex_unlock(&minors_idr_lock);
}

static int afu_open(struct inode *inode, struct file *file)
{
	struct ocxl_afu *afu;
	struct ocxl_context *ctx;
	int rc;

	pr_debug("%s for device %x\n", __func__, inode->i_rdev);

	afu = find_and_get_afu(inode->i_rdev);
	if (!afu)
		return -ENODEV;

	ctx = ocxl_context_alloc();
	if (!ctx) {
		rc = -ENOMEM;
		goto put_afu;
	}

	rc = ocxl_context_init(ctx, afu, inode->i_mapping);
	if (rc)
		goto put_afu;
	file->private_data = ctx;
	ocxl_afu_put(afu);
	return 0;

put_afu:
	ocxl_afu_put(afu);
	return rc;
}

static long afu_ioctl_attach(struct ocxl_context *ctx,
			struct ocxl_ioctl_attach __user *uarg)
{
	struct ocxl_ioctl_attach arg;
	u64 amr = 0;
	int rc;

	pr_debug("%s for context %d\n", __func__, ctx->pasid);

	if (copy_from_user(&arg, uarg, sizeof(arg)))
		return -EFAULT;

	/* Make sure reserved fields are not set for forward compatibility */
	if (arg.reserved1 || arg.reserved2 || arg.reserved3)
		return -EINVAL;

	amr = arg.amr & mfspr(SPRN_UAMOR);
	rc = ocxl_context_attach(ctx, amr);
	return rc;
}

static long afu_ioctl_get_metadata(struct ocxl_context *ctx,
		struct ocxl_ioctl_metadata __user *uarg)
{
	struct ocxl_ioctl_metadata arg;

	memset(&arg, 0, sizeof(arg));

	arg.version = 0;

	arg.afu_version_major = ctx->afu->config.version_major;
	arg.afu_version_minor = ctx->afu->config.version_minor;
	arg.pasid = ctx->pasid;
	arg.pp_mmio_size = ctx->afu->config.pp_mmio_stride;
	arg.global_mmio_size = ctx->afu->config.global_mmio_size;

	if (copy_to_user(uarg, &arg, sizeof(arg)))
		return -EFAULT;

	return 0;
}

#define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :			\
			x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :	\
			x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" :		\
			x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" :	\
			x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" :	\
			"UNKNOWN")

static long afu_ioctl(struct file *file, unsigned int cmd,
		unsigned long args)
{
	struct ocxl_context *ctx = file->private_data;
	struct ocxl_ioctl_irq_fd irq_fd;
	u64 irq_offset;
	long rc;

	pr_debug("%s for context %d, command %s\n", __func__, ctx->pasid,
		CMD_STR(cmd));

	if (ctx->status == CLOSED)
		return -EIO;

	switch (cmd) {
	case OCXL_IOCTL_ATTACH:
		rc = afu_ioctl_attach(ctx,
				(struct ocxl_ioctl_attach __user *) args);
		break;

	case OCXL_IOCTL_IRQ_ALLOC:
		rc = ocxl_afu_irq_alloc(ctx, &irq_offset);
		if (!rc) {
			rc = copy_to_user((u64 __user *) args, &irq_offset,
					sizeof(irq_offset));
			if (rc) {
				ocxl_afu_irq_free(ctx, irq_offset);
				return -EFAULT;
			}
		}
		break;

	case OCXL_IOCTL_IRQ_FREE:
		rc = copy_from_user(&irq_offset, (u64 __user *) args,
				sizeof(irq_offset));
		if (rc)
			return -EFAULT;
		rc = ocxl_afu_irq_free(ctx, irq_offset);
		break;

	case OCXL_IOCTL_IRQ_SET_FD:
		rc = copy_from_user(&irq_fd, (u64 __user *) args,
				sizeof(irq_fd));
		if (rc)
			return -EFAULT;
		if (irq_fd.reserved)
			return -EINVAL;
		rc = ocxl_afu_irq_set_fd(ctx, irq_fd.irq_offset,
					irq_fd.eventfd);
		break;

	case OCXL_IOCTL_GET_METADATA:
		rc = afu_ioctl_get_metadata(ctx,
				(struct ocxl_ioctl_metadata __user *) args);
		break;

	default:
		rc = -EINVAL;
	}
	return rc;
}

static long afu_compat_ioctl(struct file *file, unsigned int cmd,
			unsigned long args)
{
	return afu_ioctl(file, cmd, args);
}

static int afu_mmap(struct file *file, struct vm_area_struct *vma)
{
	struct ocxl_context *ctx = file->private_data;

	pr_debug("%s for context %d\n", __func__, ctx->pasid);
	return ocxl_context_mmap(ctx, vma);
}

static bool has_xsl_error(struct ocxl_context *ctx)
{
	bool ret;

	mutex_lock(&ctx->xsl_error_lock);
	ret = !!ctx->xsl_error.addr;
	mutex_unlock(&ctx->xsl_error_lock);

	return ret;
}

/*
 * Are there any events pending on the AFU
 * ctx: The AFU context
 * Returns: true if there are events pending
 */
static bool afu_events_pending(struct ocxl_context *ctx)
{
	if (has_xsl_error(ctx))
		return true;
	return false;
}

static unsigned int afu_poll(struct file *file, struct poll_table_struct *wait)
{
	struct ocxl_context *ctx = file->private_data;
	unsigned int mask = 0;
	bool closed;

	pr_debug("%s for context %d\n", __func__, ctx->pasid);

	poll_wait(file, &ctx->events_wq, wait);

	mutex_lock(&ctx->status_mutex);
	closed = (ctx->status == CLOSED);
	mutex_unlock(&ctx->status_mutex);

	if (afu_events_pending(ctx))
		mask = EPOLLIN | EPOLLRDNORM;
	else if (closed)
		mask = EPOLLERR;

	return mask;
}

/*
 * Populate the supplied buffer with a single XSL error
 * ctx:	The AFU context to report the error from
 * header: the event header to populate
 * buf: The buffer to write the body into (should be at least
 *      AFU_EVENT_BODY_XSL_ERROR_SIZE)
 * Return: the amount of buffer that was populated
 */
static ssize_t append_xsl_error(struct ocxl_context *ctx,
				struct ocxl_kernel_event_header *header,
				char __user *buf)
{
	struct ocxl_kernel_event_xsl_fault_error body;

	memset(&body, 0, sizeof(body));

	mutex_lock(&ctx->xsl_error_lock);
	if (!ctx->xsl_error.addr) {
		mutex_unlock(&ctx->xsl_error_lock);
		return 0;
	}

	body.addr = ctx->xsl_error.addr;
	body.dsisr = ctx->xsl_error.dsisr;
	body.count = ctx->xsl_error.count;

	ctx->xsl_error.addr = 0;
	ctx->xsl_error.dsisr = 0;
	ctx->xsl_error.count = 0;

	mutex_unlock(&ctx->xsl_error_lock);

	header->type = OCXL_AFU_EVENT_XSL_FAULT_ERROR;

	if (copy_to_user(buf, &body, sizeof(body)))
		return -EFAULT;

	return sizeof(body);
}

#define AFU_EVENT_BODY_MAX_SIZE sizeof(struct ocxl_kernel_event_xsl_fault_error)

/*
 * Reports events on the AFU
 * Format:
 *	Header (struct ocxl_kernel_event_header)
 *	Body (struct ocxl_kernel_event_*)
 *	Header...
 */
static ssize_t afu_read(struct file *file, char __user *buf, size_t count,
			loff_t *off)
{
	struct ocxl_context *ctx = file->private_data;
	struct ocxl_kernel_event_header header;
	ssize_t rc;
	ssize_t used = 0;
	DEFINE_WAIT(event_wait);

	memset(&header, 0, sizeof(header));

	/* Require offset to be 0 */
	if (*off != 0)
		return -EINVAL;

	if (count < (sizeof(struct ocxl_kernel_event_header) +
			AFU_EVENT_BODY_MAX_SIZE))
		return -EINVAL;

	for (;;) {
		prepare_to_wait(&ctx->events_wq, &event_wait,
				TASK_INTERRUPTIBLE);

		if (afu_events_pending(ctx))
			break;

		if (ctx->status == CLOSED)
			break;

		if (file->f_flags & O_NONBLOCK) {
			finish_wait(&ctx->events_wq, &event_wait);
			return -EAGAIN;
		}

		if (signal_pending(current)) {
			finish_wait(&ctx->events_wq, &event_wait);
			return -ERESTARTSYS;
		}

		schedule();
	}

	finish_wait(&ctx->events_wq, &event_wait);

	if (has_xsl_error(ctx)) {
		used = append_xsl_error(ctx, &header, buf + sizeof(header));
		if (used < 0)
			return used;
	}

	if (!afu_events_pending(ctx))
		header.flags |= OCXL_KERNEL_EVENT_FLAG_LAST;

	if (copy_to_user(buf, &header, sizeof(header)))
		return -EFAULT;

	used += sizeof(header);

	rc = used;
	return rc;
}

static int afu_release(struct inode *inode, struct file *file)
{
	struct ocxl_context *ctx = file->private_data;
	int rc;

	pr_debug("%s for device %x\n", __func__, inode->i_rdev);
	rc = ocxl_context_detach(ctx);
	mutex_lock(&ctx->mapping_lock);
	ctx->mapping = NULL;
	mutex_unlock(&ctx->mapping_lock);
	wake_up_all(&ctx->events_wq);
	if (rc != -EBUSY)
		ocxl_context_free(ctx);
	return 0;
}

static const struct file_operations ocxl_afu_fops = {
	.owner		= THIS_MODULE,
	.open           = afu_open,
	.unlocked_ioctl = afu_ioctl,
	.compat_ioctl   = afu_compat_ioctl,
	.mmap           = afu_mmap,
	.poll           = afu_poll,
	.read           = afu_read,
	.release        = afu_release,
};

int ocxl_create_cdev(struct ocxl_afu *afu)
{
	int rc;

	cdev_init(&afu->cdev, &ocxl_afu_fops);
	rc = cdev_add(&afu->cdev, afu->dev.devt, 1);
	if (rc) {
		dev_err(&afu->dev, "Unable to add afu char device: %d\n", rc);
		return rc;
	}
	return 0;
}

void ocxl_destroy_cdev(struct ocxl_afu *afu)
{
	cdev_del(&afu->cdev);
}

int ocxl_register_afu(struct ocxl_afu *afu)
{
	int minor;

	minor = allocate_afu_minor(afu);
	if (minor < 0)
		return minor;
	afu->dev.devt = MKDEV(MAJOR(ocxl_dev), minor);
	afu->dev.class = ocxl_class;
	return device_register(&afu->dev);
}

void ocxl_unregister_afu(struct ocxl_afu *afu)
{
	free_afu_minor(afu);
}

static char *ocxl_devnode(struct device *dev, umode_t *mode)
{
	return kasprintf(GFP_KERNEL, "ocxl/%s", dev_name(dev));
}

int ocxl_file_init(void)
{
	int rc;

	mutex_init(&minors_idr_lock);
	idr_init(&minors_idr);

	rc = alloc_chrdev_region(&ocxl_dev, 0, OCXL_NUM_MINORS, "ocxl");
	if (rc) {
		pr_err("Unable to allocate ocxl major number: %d\n", rc);
		return rc;
	}

	ocxl_class = class_create(THIS_MODULE, "ocxl");
	if (IS_ERR(ocxl_class)) {
		pr_err("Unable to create ocxl class\n");
		unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
		return PTR_ERR(ocxl_class);
	}

	ocxl_class->devnode = ocxl_devnode;
	return 0;
}

void ocxl_file_exit(void)
{
	class_destroy(ocxl_class);
	unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
	idr_destroy(&minors_idr);
}
Commit	Line	Data
5ef3166e FB	1	// SPDX-License-Identifier: GPL-2.0+
	2	// Copyright 2017 IBM Corp.
	3	#include <linux/fs.h>
	4	#include <linux/poll.h>
	5	#include <linux/sched/signal.h>
	6	#include <linux/uaccess.h>
	7	#include <uapi/misc/ocxl.h>
	8	#include "ocxl_internal.h"
	9
	10
	11	#define OCXL_NUM_MINORS 256 /* Total to reserve */
	12
	13	static dev_t ocxl_dev;
	14	static struct class *ocxl_class;
	15	static struct mutex minors_idr_lock;
	16	static struct idr minors_idr;
	17
	18	static struct ocxl_afu *find_and_get_afu(dev_t devno)
	19	{
	20	struct ocxl_afu *afu;
	21	int afu_minor;
	22
	23	afu_minor = MINOR(devno);
	24	/*
	25	* We don't declare an RCU critical section here, as our AFU
	26	* is protected by a reference counter on the device. By the time the
	27	* minor number of a device is removed from the idr, the ref count of
	28	* the device is already at 0, so no user API will access that AFU and
	29	* this function can't return it.
	30	*/
	31	afu = idr_find(&minors_idr, afu_minor);
	32	if (afu)
	33	ocxl_afu_get(afu);
	34	return afu;
	35	}
	36
	37	static int allocate_afu_minor(struct ocxl_afu *afu)
	38	{
	39	int minor;
	40
	41	mutex_lock(&minors_idr_lock);
	42	minor = idr_alloc(&minors_idr, afu, 0, OCXL_NUM_MINORS, GFP_KERNEL);
	43	mutex_unlock(&minors_idr_lock);
	44	return minor;
	45	}
	46
	47	static void free_afu_minor(struct ocxl_afu *afu)
	48	{
	49	mutex_lock(&minors_idr_lock);
	50	idr_remove(&minors_idr, MINOR(afu->dev.devt));
	51	mutex_unlock(&minors_idr_lock);
	52	}
	53
	54	static int afu_open(struct inode inode, struct file file)
	55	{
	56	struct ocxl_afu *afu;
	57	struct ocxl_context *ctx;
	58	int rc;
	59
	60	pr_debug("%s for device %x\n", __func__, inode->i_rdev);
	61
	62	afu = find_and_get_afu(inode->i_rdev);
	63	if (!afu)
	64	return -ENODEV;
65
66	ctx = ocxl_context_alloc();
67	if (!ctx) {
68	rc = -ENOMEM;
69	goto put_afu;
70	}
71
72	rc = ocxl_context_init(ctx, afu, inode->i_mapping);
73	if (rc)
74	goto put_afu;
75	file->private_data = ctx;
76	ocxl_afu_put(afu);
77	return 0;
78
79	put_afu:
80	ocxl_afu_put(afu);
81	return rc;
82	}
83
84	static long afu_ioctl_attach(struct ocxl_context *ctx,
85	struct ocxl_ioctl_attach __user *uarg)
86	{
87	struct ocxl_ioctl_attach arg;
88	u64 amr = 0;
89	int rc;
90
91	pr_debug("%s for context %d\n", __func__, ctx->pasid);
92
93	if (copy_from_user(&arg, uarg, sizeof(arg)))
94	return -EFAULT;
95
96	/* Make sure reserved fields are not set for forward compatibility */
97	if (arg.reserved1 \|\| arg.reserved2 \|\| arg.reserved3)
98	return -EINVAL;
99
100	amr = arg.amr & mfspr(SPRN_UAMOR);
101	rc = ocxl_context_attach(ctx, amr);
102	return rc;
103	}
104
07c5ccd7 AS	105	static long afu_ioctl_get_metadata(struct ocxl_context *ctx,
	106	struct ocxl_ioctl_metadata __user *uarg)
	107	{
	108	struct ocxl_ioctl_metadata arg;
	109
	110	memset(&arg, 0, sizeof(arg));
	111
	112	arg.version = 0;
	113
	114	arg.afu_version_major = ctx->afu->config.version_major;
	115	arg.afu_version_minor = ctx->afu->config.version_minor;
	116	arg.pasid = ctx->pasid;
	117	arg.pp_mmio_size = ctx->afu->config.pp_mmio_stride;
	118	arg.global_mmio_size = ctx->afu->config.global_mmio_size;
	119
	120	if (copy_to_user(uarg, &arg, sizeof(arg)))
	121	return -EFAULT;
	122
	123	return 0;
	124	}
	125
5ef3166e	126	#define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" : \
aeddad17 FB	127	x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" : \
	128	x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" : \
	129	x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" : \
07c5ccd7	130	x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" : \
5ef3166e FB	131	"UNKNOWN")
	132
	133	static long afu_ioctl(struct file *file, unsigned int cmd,
	134	unsigned long args)
	135	{
	136	struct ocxl_context *ctx = file->private_data;
aeddad17 FB	137	struct ocxl_ioctl_irq_fd irq_fd;
aeddad17 FB	138	u64 irq_offset;
5ef3166e FB	139	long rc;
	140
	141	pr_debug("%s for context %d, command %s\n", __func__, ctx->pasid,
	142	CMD_STR(cmd));
	143
	144	if (ctx->status == CLOSED)
	145	return -EIO;
	146
	147	switch (cmd) {
	148	case OCXL_IOCTL_ATTACH:
	149	rc = afu_ioctl_attach(ctx,
	150	(struct ocxl_ioctl_attach __user *) args);
	151	break;
	152
aeddad17 FB	153	case OCXL_IOCTL_IRQ_ALLOC:
	154	rc = ocxl_afu_irq_alloc(ctx, &irq_offset);
	155	if (!rc) {
	156	rc = copy_to_user((u64 __user *) args, &irq_offset,
	157	sizeof(irq_offset));
423688ab	158	if (rc) {
aeddad17	159	ocxl_afu_irq_free(ctx, irq_offset);
423688ab FB	160	return -EFAULT;
423688ab FB	161	}
aeddad17 FB	162	}
	163	break;
	164
	165	case OCXL_IOCTL_IRQ_FREE:
	166	rc = copy_from_user(&irq_offset, (u64 __user *) args,
	167	sizeof(irq_offset));
	168	if (rc)
	169	return -EFAULT;
	170	rc = ocxl_afu_irq_free(ctx, irq_offset);
	171	break;
	172
	173	case OCXL_IOCTL_IRQ_SET_FD:
	174	rc = copy_from_user(&irq_fd, (u64 __user *) args,
	175	sizeof(irq_fd));
	176	if (rc)
	177	return -EFAULT;
	178	if (irq_fd.reserved)
	179	return -EINVAL;
	180	rc = ocxl_afu_irq_set_fd(ctx, irq_fd.irq_offset,
	181	irq_fd.eventfd);
	182	break;
	183
07c5ccd7 AS	184	case OCXL_IOCTL_GET_METADATA:
	185	rc = afu_ioctl_get_metadata(ctx,
	186	(struct ocxl_ioctl_metadata __user *) args);
	187	break;
	188
5ef3166e FB	189	default:
	190	rc = -EINVAL;
	191	}
	192	return rc;
	193	}
	194
	195	static long afu_compat_ioctl(struct file *file, unsigned int cmd,
	196	unsigned long args)
	197	{
	198	return afu_ioctl(file, cmd, args);
	199	}
	200
	201	static int afu_mmap(struct file file, struct vm_area_struct vma)
	202	{
	203	struct ocxl_context *ctx = file->private_data;
	204
	205	pr_debug("%s for context %d\n", __func__, ctx->pasid);
	206	return ocxl_context_mmap(ctx, vma);
	207	}
	208
	209	static bool has_xsl_error(struct ocxl_context *ctx)
	210	{
	211	bool ret;
	212
	213	mutex_lock(&ctx->xsl_error_lock);
	214	ret = !!ctx->xsl_error.addr;
	215	mutex_unlock(&ctx->xsl_error_lock);
	216
	217	return ret;
	218	}
	219
	220	/*
	221	* Are there any events pending on the AFU
	222	* ctx: The AFU context
	223	* Returns: true if there are events pending
	224	*/
	225	static bool afu_events_pending(struct ocxl_context *ctx)
	226	{
	227	if (has_xsl_error(ctx))
	228	return true;
	229	return false;
	230	}
	231
	232	static unsigned int afu_poll(struct file file, struct poll_table_struct wait)
	233	{
	234	struct ocxl_context *ctx = file->private_data;
	235	unsigned int mask = 0;
	236	bool closed;
	237
	238	pr_debug("%s for context %d\n", __func__, ctx->pasid);
	239
	240	poll_wait(file, &ctx->events_wq, wait);
	241
	242	mutex_lock(&ctx->status_mutex);
	243	closed = (ctx->status == CLOSED);
	244	mutex_unlock(&ctx->status_mutex);
	245
	246	if (afu_events_pending(ctx))
a9a08845	247	mask = EPOLLIN \| EPOLLRDNORM;
5ef3166e	248	else if (closed)
a9a08845	249	mask = EPOLLERR;
5ef3166e FB	250
	251	return mask;
	252	}
	253
	254	/*
	255	* Populate the supplied buffer with a single XSL error
	256	* ctx: The AFU context to report the error from
	257	* header: the event header to populate
	258	* buf: The buffer to write the body into (should be at least
	259	* AFU_EVENT_BODY_XSL_ERROR_SIZE)
	260	* Return: the amount of buffer that was populated
	261	*/
	262	static ssize_t append_xsl_error(struct ocxl_context *ctx,
	263	struct ocxl_kernel_event_header *header,
	264	char __user *buf)
	265	{
	266	struct ocxl_kernel_event_xsl_fault_error body;
	267
	268	memset(&body, 0, sizeof(body));
	269
	270	mutex_lock(&ctx->xsl_error_lock);
	271	if (!ctx->xsl_error.addr) {
	272	mutex_unlock(&ctx->xsl_error_lock);
	273	return 0;
	274	}
	275
	276	body.addr = ctx->xsl_error.addr;
	277	body.dsisr = ctx->xsl_error.dsisr;
	278	body.count = ctx->xsl_error.count;
	279
	280	ctx->xsl_error.addr = 0;
	281	ctx->xsl_error.dsisr = 0;
	282	ctx->xsl_error.count = 0;
	283
	284	mutex_unlock(&ctx->xsl_error_lock);
	285
	286	header->type = OCXL_AFU_EVENT_XSL_FAULT_ERROR;
	287
	288	if (copy_to_user(buf, &body, sizeof(body)))
	289	return -EFAULT;
	290
	291	return sizeof(body);
	292	}
	293
	294	#define AFU_EVENT_BODY_MAX_SIZE sizeof(struct ocxl_kernel_event_xsl_fault_error)
	295
	296	/*
	297	* Reports events on the AFU
	298	* Format:
	299	* Header (struct ocxl_kernel_event_header)
	300	* Body (struct ocxl_kernel_event_*)
	301	* Header...
	302	*/
	303	static ssize_t afu_read(struct file file, char __user buf, size_t count,
	304	loff_t *off)
	305	{
	306	struct ocxl_context *ctx = file->private_data;
	307	struct ocxl_kernel_event_header header;
	308	ssize_t rc;
dedab7f0	309	ssize_t used = 0;
5ef3166e FB	310	DEFINE_WAIT(event_wait);
	311
	312	memset(&header, 0, sizeof(header));
	313
	314	/* Require offset to be 0 */
	315	if (*off != 0)
	316	return -EINVAL;
	317
	318	if (count < (sizeof(struct ocxl_kernel_event_header) +
	319	AFU_EVENT_BODY_MAX_SIZE))
	320	return -EINVAL;
	321
	322	for (;;) {
	323	prepare_to_wait(&ctx->events_wq, &event_wait,
	324	TASK_INTERRUPTIBLE);
	325
	326	if (afu_events_pending(ctx))
	327	break;
	328
	329	if (ctx->status == CLOSED)
	330	break;
	331
	332	if (file->f_flags & O_NONBLOCK) {
	333	finish_wait(&ctx->events_wq, &event_wait);
	334	return -EAGAIN;
	335	}
	336
	337	if (signal_pending(current)) {
	338	finish_wait(&ctx->events_wq, &event_wait);
	339	return -ERESTARTSYS;
	340	}
	341
	342	schedule();
	343	}
	344
	345	finish_wait(&ctx->events_wq, &event_wait);
	346
	347	if (has_xsl_error(ctx)) {
	348	used = append_xsl_error(ctx, &header, buf + sizeof(header));
	349	if (used < 0)
	350	return used;
	351	}
	352
	353	if (!afu_events_pending(ctx))
	354	header.flags \|= OCXL_KERNEL_EVENT_FLAG_LAST;
	355
	356	if (copy_to_user(buf, &header, sizeof(header)))
	357	return -EFAULT;
	358
	359	used += sizeof(header);
	360
423688ab	361	rc = used;
5ef3166e FB	362	return rc;
	363	}
	364
	365	static int afu_release(struct inode inode, struct file file)
	366	{
	367	struct ocxl_context *ctx = file->private_data;
	368	int rc;
	369
	370	pr_debug("%s for device %x\n", __func__, inode->i_rdev);
	371	rc = ocxl_context_detach(ctx);
	372	mutex_lock(&ctx->mapping_lock);
	373	ctx->mapping = NULL;
	374	mutex_unlock(&ctx->mapping_lock);
	375	wake_up_all(&ctx->events_wq);
	376	if (rc != -EBUSY)
	377	ocxl_context_free(ctx);
	378	return 0;
	379	}
	380
	381	static const struct file_operations ocxl_afu_fops = {
	382	.owner = THIS_MODULE,
	383	.open = afu_open,
	384	.unlocked_ioctl = afu_ioctl,
	385	.compat_ioctl = afu_compat_ioctl,
	386	.mmap = afu_mmap,
	387	.poll = afu_poll,
	388	.read = afu_read,
	389	.release = afu_release,
	390	};
	391
	392	int ocxl_create_cdev(struct ocxl_afu *afu)
	393	{
	394	int rc;
	395
	396	cdev_init(&afu->cdev, &ocxl_afu_fops);
	397	rc = cdev_add(&afu->cdev, afu->dev.devt, 1);
	398	if (rc) {
	399	dev_err(&afu->dev, "Unable to add afu char device: %d\n", rc);
	400	return rc;
	401	}
	402	return 0;
	403	}
	404
	405	void ocxl_destroy_cdev(struct ocxl_afu *afu)
	406	{
	407	cdev_del(&afu->cdev);
	408	}
	409
	410	int ocxl_register_afu(struct ocxl_afu *afu)
	411	{
	412	int minor;
	413
	414	minor = allocate_afu_minor(afu);
	415	if (minor < 0)
	416	return minor;
	417	afu->dev.devt = MKDEV(MAJOR(ocxl_dev), minor);
	418	afu->dev.class = ocxl_class;
	419	return device_register(&afu->dev);
	420	}
	421
	422	void ocxl_unregister_afu(struct ocxl_afu *afu)
	423	{
	424	free_afu_minor(afu);
	425	}
426
427	static char ocxl_devnode(struct device dev, umode_t *mode)
428	{
429	return kasprintf(GFP_KERNEL, "ocxl/%s", dev_name(dev));
430	}
431
432	int ocxl_file_init(void)
433	{
434	int rc;
435
436	mutex_init(&minors_idr_lock);
437	idr_init(&minors_idr);
438
439	rc = alloc_chrdev_region(&ocxl_dev, 0, OCXL_NUM_MINORS, "ocxl");
440	if (rc) {
441	pr_err("Unable to allocate ocxl major number: %d\n", rc);
442	return rc;
443	}
444
445	ocxl_class = class_create(THIS_MODULE, "ocxl");
446	if (IS_ERR(ocxl_class)) {
447	pr_err("Unable to create ocxl class\n");
448	unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
449	return PTR_ERR(ocxl_class);
450	}
451
452	ocxl_class->devnode = ocxl_devnode;
453	return 0;
454	}
455
456	void ocxl_file_exit(void)
457	{
458	class_destroy(ocxl_class);
459	unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
460	idr_destroy(&minors_idr);
461	}