1 files changed, 37 insertions, 89 deletions

diff --git a/kernel/ethosu_buffer.c b/kernel/ethosu_buffer.c
index 07c8033..bf7d745 100644
--- a/kernel/ethosu_buffer.c
+++ b/kernel/ethosu_buffer.c
@@ -15,7 +15,6 @@
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, you can access it online at
  * http://www.gnu.org/licenses/gpl-2.0.html.
- *
  */
 
 /****************************************************************************
@@ -45,17 +44,14 @@ static int ethosu_buffer_release(struct inode *inode,
 static int ethosu_buffer_mmap(struct file *file,
 			      struct vm_area_struct *vma);
 
-static long ethosu_buffer_ioctl(struct file *file,
-				unsigned int cmd,
-				unsigned long arg);
+static loff_t ethosu_buffer_llseek(struct file *file,
+				   loff_t offset,
+				   int whence);
 
 static const struct file_operations ethosu_buffer_fops = {
-	.release        = &ethosu_buffer_release,
-	.mmap           = &ethosu_buffer_mmap,
-	.unlocked_ioctl = &ethosu_buffer_ioctl,
-#ifdef CONFIG_COMPAT
-	.compat_ioctl   = &ethosu_buffer_ioctl,
-#endif
+	.release = &ethosu_buffer_release,
+	.mmap    = &ethosu_buffer_mmap,
+	.llseek  = &ethosu_buffer_llseek,
 };
 
 /****************************************************************************
@@ -75,8 +71,8 @@ static void ethosu_buffer_destroy(struct kref *kref)
 
 	dev_dbg(dev, "Buffer destroy. buf=0x%pK", buf);
 
-	memset(buf->cpu_addr, 0, buf->capacity);
-	dma_free_coherent(dev, buf->capacity, buf->cpu_addr,
+	memset(buf->cpu_addr, 0, buf->size);
+	dma_free_coherent(dev, buf->size, buf->cpu_addr,
 			  buf->dma_addr);
 
 	memset(buf, 0, sizeof(*buf));
@@ -108,78 +104,43 @@ static int ethosu_buffer_mmap(struct file *file,
 		file, buf);
 
 	ret = dma_mmap_coherent(dev, vma, buf->cpu_addr,
-				buf->dma_addr, buf->capacity);
+				buf->dma_addr, buf->size);
 
 	return ret;
 }
 
-static long ethosu_buffer_ioctl(struct file *file,
-				unsigned int cmd,
-				unsigned long arg)
+static loff_t ethosu_buffer_llseek(struct file *file,
+				   loff_t offset,
+				   int whence)
 {
 	struct ethosu_buffer *buf = file->private_data;
-	struct device *dev = buf->dev;
-	void __user *udata = (void __user *)arg;
-	int ret;
-
-	ret = device_lock_interruptible(dev);
-	if (ret)
-		return ret;
-
-	switch (cmd) {
-	case ETHOSU_IOCTL_BUFFER_SET: {
-		struct ethosu_uapi_buffer uapi;
-
-		if (copy_from_user(&uapi, udata, sizeof(uapi))) {
-			ret = -EFAULT;
-			break;
-		}
-
-		dev_dbg(dev,
-			"Buffer ioctl: Buffer set. size=%u, offset=%u\n",
-			uapi.size, uapi.offset);
 
-		ret = ethosu_buffer_resize(buf, uapi.size, uapi.offset);
-		break;
-	}
-	case ETHOSU_IOCTL_BUFFER_GET: {
-		struct ethosu_uapi_buffer uapi = { 0 };
-
-		uapi.size = buf->size;
-		uapi.offset = buf->offset;
-
-		dev_dbg(dev,
-			"Buffer ioctl: Buffer get. size=%u, offset=%u\n",
-			uapi.size, uapi.offset);
-
-		if (copy_to_user(udata, &uapi, sizeof(uapi))) {
-			ret = -EFAULT;
-			break;
-		}
+	if (offset != 0)
+		return -EINVAL;
 
-		ret = 0;
-		break;
-	}
-	default: {
-		dev_err(dev, "Invalid ioctl. cmd=%u, arg=%lu",
-			cmd, arg);
-		ret = -ENOIOCTLCMD;
-		break;
-	}
+	/*
+	 * SEEK_END and SEEK_SET is supported with a zero offset to allow buffer
+	 * size discovery using seek functions e.g.
+	 * size = lseek(buf_fd, 0, SEEK_END);
+	 * lseek(buf_fd, 0, SEEK_SET);
+	 */
+	switch (whence) {
+	case SEEK_END:
+		return buf->size;
+	case SEEK_SET:
+		return 0;
+	default:
+		return -EINVAL;
 	}
-
-	device_unlock(dev);
-
-	return ret;
 }
 
 int ethosu_buffer_create(struct device *dev,
-			 size_t capacity)
+			 size_t size)
 {
 	struct ethosu_buffer *buf;
 	int ret = -ENOMEM;
 
-	if (!capacity)
+	if (!size)
 		return -EINVAL;
 
 	buf = devm_kzalloc(dev, sizeof(*buf), GFP_KERNEL);
@@ -187,13 +148,11 @@ int ethosu_buffer_create(struct device *dev,
 		return -ENOMEM;
 
 	buf->dev = dev;
-	buf->capacity = capacity;
-	buf->offset = 0;
-	buf->size = 0;
+	buf->size = size;
 	kref_init(&buf->kref);
 
-	buf->cpu_addr = dma_alloc_coherent(dev, capacity,
-					   &buf->dma_addr, GFP_KERNEL);
+	buf->cpu_addr = dma_alloc_coherent(dev, size, &buf->dma_addr,
+					   GFP_KERNEL);
 	if (!buf->cpu_addr)
 		goto free_buf;
 
@@ -203,17 +162,19 @@ int ethosu_buffer_create(struct device *dev,
 		goto free_dma;
 
 	buf->file = fget(ret);
+	buf->file->f_mode |= FMODE_LSEEK;
+
 	fput(buf->file);
 
 	dev_dbg(dev,
-		"Buffer create. file=0x%pK, fd=%d, buf=0x%pK, capacity=%zu, cpu_addr=0x%pK, dma_addr=0x%llx, phys_addr=0x%llx\n",
-		buf->file, ret, buf, capacity, buf->cpu_addr, buf->dma_addr,
+		"Buffer create. file=0x%pK, fd=%d, buf=0x%pK, size=%zu, cpu_addr=0x%pK, dma_addr=0x%llx, phys_addr=0x%llx\n",
+		buf->file, ret, buf, size, buf->cpu_addr, buf->dma_addr,
 		virt_to_phys(buf->cpu_addr));
 
 	return ret;
 
 free_dma:
-	dma_free_coherent(dev, buf->capacity, buf->cpu_addr,
+	dma_free_coherent(dev, buf->size, buf->cpu_addr,
 			  buf->dma_addr);
 
 free_buf:
@@ -254,16 +215,3 @@ void ethosu_buffer_put(struct ethosu_buffer *buf)
 {
 	kref_put(&buf->kref, ethosu_buffer_destroy);
 }
-
-int ethosu_buffer_resize(struct ethosu_buffer *buf,
-			 size_t size,
-			 size_t offset)
-{
-	if ((size + offset) > buf->capacity)
-		return -EINVAL;
-
-	buf->size = size;
-	buf->offset = offset;
-
-	return 0;
-}