[PATCH v2 5/6] firmware: Add request_firmware_prefer_user() function

Pali Rohár
2017-11-09T23:38:57Z

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.rohar@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