@@ -17,9 +17,12 @@
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/poll.h>
+#include <linux/sched/signal.h>
#include <misc/ocxl.h>
+#include <uapi/misc/cxl.h>
+
#include "backend.h"
#include "ocxl_hw.h"
@@ -929,9 +932,99 @@ static unsigned int afu_poll(struct file *file, struct poll_table_struct *poll)
return mask;
}
+/**
+ * afu_read() - perform a read on the context for any event
+ * @file: File associated with the adapter context.
+ * @buf: Buffer to receive the data.
+ * @count: Size of buffer (maximum bytes that can be read).
+ * @off: Offset.
+ *
+ * Return: size of the data read on success, -errno on failure
+ */
+static ssize_t afu_read(struct file *file, char __user *buf, size_t count,
+ loff_t *off)
+{
+ struct ocxlflash_context *ctx = file->private_data;
+ struct device *dev = ctx->hw_afu->dev;
+ struct cxl_event event;
+ ulong lock_flags;
+ ssize_t esize;
+ ssize_t rc;
+ int bit;
+ DEFINE_WAIT(event_wait);
+
+ if (*off != 0) {
+ dev_err(dev, "%s: Non-zero offset not supported, off=%lld\n",
+ __func__, *off);
+ rc = -EINVAL;
+ goto out;
+ }
+
+ spin_lock_irqsave(&ctx->slock, lock_flags);
+
+ for (;;) {
+ prepare_to_wait(&ctx->wq, &event_wait, TASK_INTERRUPTIBLE);
+
+ if (ctx_event_pending(ctx))
+ break;
+
+ if (file->f_flags & O_NONBLOCK) {
+ dev_err(dev, "%s: File cannot be blocked on I/O\n",
+ __func__);
+ rc = -EAGAIN;
+ goto err;
+ }
+
+ if (signal_pending(current)) {
+ dev_err(dev, "%s: Signal pending on the process\n",
+ __func__);
+ rc = -ERESTARTSYS;
+ goto err;
+ }
+
+ spin_unlock_irqrestore(&ctx->slock, lock_flags);
+ schedule();
+ spin_lock_irqsave(&ctx->slock, lock_flags);
+ }
+
+ finish_wait(&ctx->wq, &event_wait);
+
+ memset(&event, 0, sizeof(event));
+ event.header.process_element = ctx->pe;
+ event.header.size = sizeof(struct cxl_event_header);
+ if (ctx->pending_irq) {
+ esize = sizeof(struct cxl_event_afu_interrupt);
+ event.header.size += esize;
+ event.header.type = CXL_EVENT_AFU_INTERRUPT;
+
+ bit = find_first_bit(&ctx->irq_bitmap, ctx->num_irqs);
+ clear_bit(bit, &ctx->irq_bitmap);
+ event.irq.irq = bit + 1;
+ if (bitmap_empty(&ctx->irq_bitmap, ctx->num_irqs))
+ ctx->pending_irq = false;
+ }
+
+ spin_unlock_irqrestore(&ctx->slock, lock_flags);
+
+ if (copy_to_user(buf, &event, event.header.size)) {
+ dev_err(dev, "%s: copy_to_user failed\n", __func__);
+ rc = -EFAULT;
+ goto out;
+ }
+
+ rc = event.header.size;
+out:
+ return rc;
+err:
+ finish_wait(&ctx->wq, &event_wait);
+ spin_unlock_irqrestore(&ctx->slock, lock_flags);
+ goto out;
+}
+
static const struct file_operations ocxl_afu_fops = {
.owner = THIS_MODULE,
.poll = afu_poll,
+ .read = afu_read,
};
#define PATCH_FOPS(NAME) \
@@ -977,6 +1070,7 @@ static struct file *ocxlflash_get_fd(void *ctx_cookie,
/* Patch the file ops that are not defined */
if (fops) {
PATCH_FOPS(poll);
+ PATCH_FOPS(read);
} else /* Use default ops */
fops = (struct file_operations *)&ocxl_afu_fops;