Remove buffer capacity, offset and resize in UAPI

The UAPI no longer supports the buffer capacity, offset and resize
functionality. Instead, the UAPI now only accepts a fixed size given at
the creation of the buffer. This change was made because the features
were not used and made the buffer handling more complicated. The user
knows how big buffers they need for their networks so they don't need
resize support or partial buffer usage support by having separate size
and capacity with an offset.

Without these features, the buffer instance no longer needs any IOCTL
call support so it has been removed. However, to still be able to check
the size of a buffer from its file descriptor, seek support has been
implemented so lseek and similar functions can be used to get the size.

The driver library's clear function that previously only reset the size
and offset values of the buffer will now clear the buffer content
instead.

These are breaking changes so the Linux kernel NPU driver version and
the driver library version have been given major version bumps. All the
tests and other applications affected by these changes have been updated
accordingly.

Change-Id: Ifc34cf04724a95853ad23fd7398dd286f73bcdab
Signed-off-by: Mikael Olsson <mikael.olsson@arm.com>

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;
-}