[PATCH v11 5/8] misc: fw_loader: implement request_firmware_size() OP

[Christian Marangi <ansuelsmth@gmail.com>]

It might be useful to get the firmware size before reading it to allocate
the correct size. This is needed for case where the firmware size change
across different firmware version and is not always the same. In such case
the only way to handle this scenario is to allocate a big-enough buffer to
read the firmware.

To better handle this, introduce the request_firmware_size() OP to get the
firmware size before reading it. This way proper buffer can be allocated
and dynamic firmware size can be better supported.

FS loader is updated to handle the new .get_size() handler.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/misc/fw_loader/fs_loader.c        | 28 +++++++++++++++++++++++
 drivers/misc/fw_loader/fw_loader-uclass.c | 19 +++++++++++++++
 drivers/misc/fw_loader/internal.h         |  7 ++++++
 include/fw_loader.h                       |  9 ++++++++
 4 files changed, 63 insertions(+)

diff --git a/drivers/misc/fw_loader/fs_loader.c b/drivers/misc/fw_loader/fs_loader.c
index cc1bbd2f0db9..b7ba57ce6778 100644
--- a/drivers/misc/fw_loader/fs_loader.c
+++ b/drivers/misc/fw_loader/fs_loader.c
@@ -190,8 +190,36 @@ out:
 	return ret;
 }
 
+/**
+ * fw_get_filesystem_firmware_size - get firmware size.
+ * @dev: An instance of a driver.
+ *
+ * Return: Size of firmware, negative value when error.
+ */
+static int fw_get_filesystem_firmware_size(struct udevice *dev)
+{
+	struct firmware *upriv = dev_get_uclass_priv(dev);
+	loff_t size;
+	int ret;
+
+	ret = fw_get_filesystem_mount(dev);
+	if (ret)
+		goto out;
+
+	ret = __fw_get_filesystem_firmware_size(dev, upriv->name, &size);
+	if (ret)
+		goto out;
+
+	ret = size;
+
+out:
+	fw_get_filesystem_release(dev);
+	return ret;
+}
+
 static const struct fw_loader_ops fs_loader_ops = {
 	.get_firmware = fw_get_filesystem_firmware,
+	.get_size = fw_get_filesystem_firmware_size,
 };
 
 static const struct udevice_id fs_loader_ids[] = {
diff --git a/drivers/misc/fw_loader/fw_loader-uclass.c b/drivers/misc/fw_loader/fw_loader-uclass.c
index 7f19d6c4af4c..4e67f2559fa2 100644
--- a/drivers/misc/fw_loader/fw_loader-uclass.c
+++ b/drivers/misc/fw_loader/fw_loader-uclass.c
@@ -210,3 +210,22 @@ int request_firmware_into_buf(struct udevice *dev,
 
 	return ops->get_firmware(dev);
 }
+
+int request_firmware_size(struct udevice *dev, const char *name)
+{
+	const struct fw_loader_ops *ops;
+	int ret;
+
+	if (!dev)
+		return -EINVAL;
+
+	ret = _request_firmware_prepare(dev, name, NULL, 0, 0);
+	if (ret < 0) /* error */
+		return ret;
+
+	ops = fw_loader_get_ops(dev);
+	if (!ops->get_size)
+		return -EOPNOTSUPP;
+
+	return ops->get_size(dev);
+}
diff --git a/drivers/misc/fw_loader/internal.h b/drivers/misc/fw_loader/internal.h
index 9ff43e872554..1abe7504a81e 100644
--- a/drivers/misc/fw_loader/internal.h
+++ b/drivers/misc/fw_loader/internal.h
@@ -32,6 +32,13 @@ struct fw_loader_ops {
 	 * @dev:	Firmware Loader device to read firmware from
 	 */
 	int (*get_firmware)(struct udevice *dev);
+
+	/**
+	 * get_size() - get firmware size from Firmware Loader driver
+	 *
+	 * @dev:	Firmware Loader device to get firmware size from
+	 */
+	int (*get_size)(struct udevice *dev);
 };
 
 #define fw_loader_get_ops(dev)	((const struct fw_loader_ops *)(dev)->driver->ops)
diff --git a/include/fw_loader.h b/include/fw_loader.h
index 99c47380a172..01f242dcbefd 100644
--- a/include/fw_loader.h
+++ b/include/fw_loader.h
@@ -38,6 +38,15 @@ int request_firmware_into_buf(struct udevice *dev,
 			      const char *name,
 			      void *buf, size_t size, u32 offset);
 
+/**
+ * request_firmware_size - Get firmware size.
+ * @dev: An instance of a driver.
+ * @name: Name of firmware file.
+ *
+ * Return: Size of firmware, negative value when error.
+ */
+int request_firmware_size(struct udevice *dev, const char *name);
+
 /**
  * request_firmware_into_buf_via_script() -
  * Load firmware using a U-Boot script and copy to buffer
-- 
2.55.0