firmware_loader: formalize built-in firmware API

Formalize the built-in firmware with a proper API. This can later
be used by other callers where all they need is built-in firmware.

We export the firmware_request_builtin() call for now only
under the TEST_FIRMWARE symbol namespace as there are no
direct modular users for it. If they pop up they are free
to export it generally. Built-in code always gets access to
the callers and we'll demonstrate a hidden user which has been
lurking in the kernel for a while and the reason why using a
proper API was better long term.

Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20211021155843.1969401-2-mcgrof@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/base/firmware_loader/firmware.h b/drivers/base/firmware_loader/firmware.h
index a3014e9e2c85..2889f446ad41 100644
--- a/drivers/base/firmware_loader/firmware.h
+++ b/drivers/base/firmware_loader/firmware.h
@@ -151,6 +151,23 @@ static inline void fw_state_done(struct fw_priv *fw_priv)
 
 int assign_fw(struct firmware *fw, struct device *device);
 
+#ifdef CONFIG_FW_LOADER
+bool firmware_is_builtin(const struct firmware *fw);
+bool firmware_request_builtin_buf(struct firmware *fw, const char *name,
+				  void *buf, size_t size);
+#else /* module case */
+static inline bool firmware_is_builtin(const struct firmware *fw)
+{
+	return false;
+}
+static inline bool firmware_request_builtin_buf(struct firmware *fw,
+						const char *name,
+						void *buf, size_t size)
+{
+	return false;
+}
+#endif
+
 #ifdef CONFIG_FW_LOADER_PAGED_BUF
 void fw_free_paged_buf(struct fw_priv *fw_priv);
 int fw_grow_paged_buf(struct fw_priv *fw_priv, int pages_needed);