Merge tag 'driver-core-4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the driver core patchset for 4.18-rc1.

  The large chunk of these are firmware core documentation and api
  updates. Nothing major there, just better descriptions for others to
  be able to understand the firmware code better. There's also a user
  for a new firmware api call.

  Other than that, there are some minor updates for debugfs, kernfs, and
  the driver core itself.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'driver-core-4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (23 commits)
  driver core: hold dev's parent lock when needed
  driver-core: return EINVAL error instead of BUG_ON()
  driver core: add __printf verification to device_create_groups_vargs
  mm: memory_hotplug: use put_device() if device_register fail
  base: core: fix typo 'can by' to 'can be'
  debugfs: inode: debugfs_create_dir uses mode permission from parent
  debugfs: Re-use kstrtobool_from_user()
  Documentation: clarify firmware_class provenance and why we can't rename the module
  Documentation: remove stale firmware API reference
  Documentation: fix few typos and clarifications for the firmware loader
  ath10k: re-enable the firmware fallback mechanism for testmode
  ath10k: use firmware_request_nowarn() to load firmware
  firmware: add firmware_request_nowarn() - load firmware without warnings
  firmware_loader: make firmware_fallback_sysfs() print more useful
  firmware_loader: move kconfig FW_LOADER entries to its own file
  firmware_loader: replace ---help--- with help
  firmware_loader: enhance Kconfig documentation over FW_LOADER
  firmware_loader: document firmware_sysfs_fallback()
  firmware: rename fw_sysfs_fallback to firmware_fallback_sysfs()
  firmware: use () to terminate kernel-doc function names
  ...

1 files changed, 39 insertions, 14 deletions

diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c
index 358354148dec..b676a99c469c 100644
--- a/drivers/base/firmware_loader/fallback.c
+++ b/drivers/base/firmware_loader/fallback.c
@@ -125,7 +125,7 @@ static ssize_t timeout_show(struct class *class, struct class_attribute *attr,
 }
 
 /**
- * firmware_timeout_store - set number of seconds to wait for firmware
+ * firmware_timeout_store() - set number of seconds to wait for firmware
  * @class: device class pointer
  * @attr: device attribute pointer
  * @buf: buffer to scan for timeout value
@@ -239,7 +239,7 @@ static int map_fw_priv_pages(struct fw_priv *fw_priv)
 }
 
 /**
- * firmware_loading_store - set value in the 'loading' control file
+ * firmware_loading_store() - set value in the 'loading' control file
  * @dev: device pointer
  * @attr: device attribute pointer
  * @buf: buffer to scan for loading control value
@@ -431,7 +431,7 @@ static int fw_realloc_pages(struct fw_sysfs *fw_sysfs, int min_size)
 }
 
 /**
- * firmware_data_write - write method for firmware
+ * firmware_data_write() - write method for firmware
  * @filp: open sysfs file
  * @kobj: kobject for the device
  * @bin_attr: bin_attr structure
@@ -512,7 +512,7 @@ static const struct attribute_group *fw_dev_attr_groups[] = {
 
 static struct fw_sysfs *
 fw_create_instance(struct firmware *firmware, const char *fw_name,
-		   struct device *device, unsigned int opt_flags)
+		   struct device *device, enum fw_opt opt_flags)
 {
 	struct fw_sysfs *fw_sysfs;
 	struct device *f_dev;
@@ -537,7 +537,7 @@ exit:
 }
 
 /**
- * fw_load_sysfs_fallback - load a firmware via the sysfs fallback mechanism
+ * fw_load_sysfs_fallback() - load a firmware via the sysfs fallback mechanism
  * @fw_sysfs: firmware sysfs information for the firmware to load
  * @opt_flags: flags of options, FW_OPT_*
  * @timeout: timeout to wait for the load
@@ -545,7 +545,7 @@ exit:
  * In charge of constructing a sysfs fallback interface for firmware loading.
  **/
 static int fw_load_sysfs_fallback(struct fw_sysfs *fw_sysfs,
-				  unsigned int opt_flags, long timeout)
+				  enum fw_opt opt_flags, long timeout)
 {
 	int retval = 0;
 	struct device *f_dev = &fw_sysfs->dev;
@@ -599,7 +599,7 @@ err_put_dev:
 
 static int fw_load_from_user_helper(struct firmware *firmware,
 				    const char *name, struct device *device,
-				    unsigned int opt_flags)
+				    enum fw_opt opt_flags)
 {
 	struct fw_sysfs *fw_sysfs;
 	long timeout;
@@ -640,7 +640,7 @@ out_unlock:
 	return ret;
 }
 
-static bool fw_force_sysfs_fallback(unsigned int opt_flags)
+static bool fw_force_sysfs_fallback(enum fw_opt opt_flags)
 {
 	if (fw_fallback_config.force_sysfs_fallback)
 		return true;
@@ -649,7 +649,7 @@ static bool fw_force_sysfs_fallback(unsigned int opt_flags)
 	return true;
 }
 
-static bool fw_run_sysfs_fallback(unsigned int opt_flags)
+static bool fw_run_sysfs_fallback(enum fw_opt opt_flags)
 {
 	if (fw_fallback_config.ignore_sysfs_fallback) {
 		pr_info_once("Ignoring firmware sysfs fallback due to sysctl knob\n");
@@ -662,14 +662,39 @@ static bool fw_run_sysfs_fallback(unsigned int opt_flags)
 	return fw_force_sysfs_fallback(opt_flags);
 }
 
-int fw_sysfs_fallback(struct firmware *fw, const char *name,
-		      struct device *device,
-		      unsigned int opt_flags,
-		      int ret)
+/**
+ * firmware_fallback_sysfs() - use the fallback mechanism to find firmware
+ * @fw: pointer to firmware image
+ * @name: name of firmware file to look for
+ * @device: device for which firmware is being loaded
+ * @opt_flags: options to control firmware loading behaviour
+ * @ret: return value from direct lookup which triggered the fallback mechanism
+ *
+ * This function is called if direct lookup for the firmware failed, it enables
+ * a fallback mechanism through userspace by exposing a sysfs loading
+ * interface. Userspace is in charge of loading the firmware through the syfs
+ * loading interface. This syfs fallback mechanism may be disabled completely
+ * on a system by setting the proc sysctl value ignore_sysfs_fallback to true.
+ * If this false we check if the internal API caller set the @FW_OPT_NOFALLBACK
+ * flag, if so it would also disable the fallback mechanism. A system may want
+ * to enfoce the sysfs fallback mechanism at all times, it can do this by
+ * setting ignore_sysfs_fallback to false and force_sysfs_fallback to true.
+ * Enabling force_sysfs_fallback is functionally equivalent to build a kernel
+ * with CONFIG_FW_LOADER_USER_HELPER_FALLBACK.
+ **/
+int firmware_fallback_sysfs(struct firmware *fw, const char *name,
+			    struct device *device,
+			    enum fw_opt opt_flags,
+			    int ret)
 {
 	if (!fw_run_sysfs_fallback(opt_flags))
 		return ret;
 
-	dev_warn(device, "Falling back to user helper\n");
+	if (!(opt_flags & FW_OPT_NO_WARN))
+		dev_warn(device, "Falling back to syfs fallback for: %s\n",
+				 name);
+	else
+		dev_dbg(device, "Falling back to sysfs fallback for: %s\n",
+				name);
 	return fw_load_from_user_helper(fw, name, device, opt_flags);
 }