This function works pretty much like request_firmware(), but it prefer
usermode helper. If usermode helper fails then it fallback to direct
access. Useful for dynamic or model specific firmware data.

Signed-off-by: Pali Rohár <pali.ro...@gmail.com>
---
 drivers/base/firmware_class.c |   45 +++++++++++++++++++++++++++++++++++++++--
 include/linux/firmware.h      |    9 +++++++++
 2 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index 4b57cf5..c3a9fe5 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -195,6 +195,11 @@ static int __fw_state_check(struct fw_state *fw_st, enum 
fw_status status)
 #endif
 #define FW_OPT_NO_WARN (1U << 3)
 #define FW_OPT_NOCACHE (1U << 4)
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+#define FW_OPT_PREFER_USER     (1U << 5)
+#else
+#define FW_OPT_PREFER_USER     0
+#endif
 
 struct firmware_cache {
        /* firmware_buf instance will be added into the below list */
@@ -1214,13 +1219,26 @@ static void fw_abort_batch_reqs(struct firmware *fw)
        if (ret <= 0) /* error or already assigned */
                goto out;
 
-       ret = fw_get_filesystem_firmware(device, fw->priv);
+       if (opt_flags & FW_OPT_PREFER_USER) {
+               ret = fw_load_from_user_helper(fw, name, device, opt_flags, 
timeout);
+               if (ret && !(opt_flags & FW_OPT_NO_WARN)) {
+                       dev_warn(device,
+                                "User helper firmware load for %s failed with 
error %d\n",
+                                name, ret);
+                       dev_warn(device, "Falling back to direct firmware 
load\n");
+               }
+       } else {
+               ret = -EINVAL;
+       }
+
+       if (ret)
+               ret = fw_get_filesystem_firmware(device, fw->priv);
        if (ret) {
                if (!(opt_flags & FW_OPT_NO_WARN))
                        dev_warn(device,
                                 "Direct firmware load for %s failed with error 
%d\n",
                                 name, ret);
-               if (opt_flags & FW_OPT_USERHELPER) {
+               if ((opt_flags & FW_OPT_USERHELPER) && !(opt_flags & 
FW_OPT_PREFER_USER)) {
                        dev_warn(device, "Falling back to user helper\n");
                        ret = fw_load_from_user_helper(fw, name, device,
                                                       opt_flags);
@@ -1329,6 +1347,29 @@ int request_firmware_direct(const struct firmware 
**firmware_p,
 EXPORT_SYMBOL(request_firmware_into_buf);
 
 /**
+ * request_firmware_prefer_user: - prefer usermode helper for loading firmware
+ * @firmware_p: pointer to firmware image
+ * @name: name of firmware file
+ * @device: device for which firmware is being loaded
+ *
+ * This function works pretty much like request_firmware(), but it prefer
+ * usermode helper. If usermode helper fails then it fallback to direct access.
+ * Useful for dynamic or model specific firmware data.
+ **/
+int request_firmware_prefer_user(const struct firmware **firmware_p,
+                           const char *name, struct device *device)
+{
+       int ret;
+
+       __module_get(THIS_MODULE);
+       ret = _request_firmware(firmware_p, name, device, NULL, 0,
+                               FW_OPT_UEVENT | FW_OPT_PREFER_USER);
+       module_put(THIS_MODULE);
+       return ret;
+}
+EXPORT_SYMBOL_GPL(request_firmware_prefer_user);
+
+/**
  * release_firmware: - release the resource associated with a firmware image
  * @fw: firmware resource to release
  **/
diff --git a/include/linux/firmware.h b/include/linux/firmware.h
index d450808..8584528 100644
--- a/include/linux/firmware.h
+++ b/include/linux/firmware.h
@@ -48,6 +48,8 @@ int request_firmware_nowait(
        void (*cont)(const struct firmware *fw, void *context));
 int request_firmware_direct(const struct firmware **fw, const char *name,
                            struct device *device);
+int request_firmware_prefer_user(const struct firmware **fw, const char *name,
+                                struct device *device);
 int request_firmware_into_buf(const struct firmware **firmware_p,
        const char *name, struct device *device, void *buf, size_t size);
 
@@ -78,6 +80,13 @@ static inline int request_firmware_direct(const struct 
firmware **fw,
        return -EINVAL;
 }
 
+static inline int request_firmware_prefer_user(const struct firmware **fw,
+                                              const char *name,
+                                              struct device *device)
+{
+       return -EINVAL;
+}
+
 static inline int request_firmware_into_buf(const struct firmware **firmware_p,
        const char *name, struct device *device, void *buf, size_t size)
 {
-- 
1.7.9.5

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