firmware_loader: Add firmware-upload support

Extend the firmware subsystem to support a persistent sysfs interface that
userspace may use to initiate a firmware update. For example, FPGA based
PCIe cards load firmware and FPGA images from local FLASH when the card
boots. The images in FLASH may be updated with new images provided by the
user at his/her convenience.

A device driver may call firmware_upload_register() to expose persistent
"loading" and "data" sysfs files. These files are used in the same way as
the fallback sysfs "loading" and "data" files. When 0 is written to
"loading" to complete the write of firmware data, the data is transferred
to the lower-level driver using pre-registered call-back functions. The
data transfer is done in the context of a kernel worker thread.

Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Tianfei zhang <tianfei.zhang@intel.com>
Tested-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Signed-off-by: Russ Weight <russell.h.weight@intel.com>
Link: https://lore.kernel.org/r/20220421212204.36052-5-russell.h.weight@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 6 insertions, 10 deletions

diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index 6ac6c7753acc..9a8579e56c26 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -92,9 +92,9 @@ static inline struct fw_priv *to_fw_priv(struct kref *ref)
  * guarding for corner cases a global lock should be OK */
 DEFINE_MUTEX(fw_lock);
 
-static struct firmware_cache fw_cache;
+struct firmware_cache fw_cache;
 
-static void fw_state_init(struct fw_priv *fw_priv)
+void fw_state_init(struct fw_priv *fw_priv)
 {
 	struct fw_state *fw_st = &fw_priv->fw_st;
 
@@ -164,13 +164,9 @@ static struct fw_priv *__lookup_fw_priv(const char *fw_name)
 }
 
 /* Returns 1 for batching firmware requests with the same name */
-static int alloc_lookup_fw_priv(const char *fw_name,
-				struct firmware_cache *fwc,
-				struct fw_priv **fw_priv,
-				void *dbuf,
-				size_t size,
-				size_t offset,
-				u32 opt_flags)
+int alloc_lookup_fw_priv(const char *fw_name, struct firmware_cache *fwc,
+			 struct fw_priv **fw_priv, void *dbuf, size_t size,
+			 size_t offset, u32 opt_flags)
 {
 	struct fw_priv *tmp;
 
@@ -225,7 +221,7 @@ static void __free_fw_priv(struct kref *ref)
 	kfree(fw_priv);
 }
 
-static void free_fw_priv(struct fw_priv *fw_priv)
+void free_fw_priv(struct fw_priv *fw_priv)
 {
 	struct firmware_cache *fwc = fw_priv->fwc;
 	spin_lock(&fwc->lock);