summaryrefslogtreecommitdiffstats
path: root/Documentation/driver-api/firmware/introduction.rst
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/driver-api/firmware/introduction.rst')
-rw-r--r--Documentation/driver-api/firmware/introduction.rst27
1 files changed, 27 insertions, 0 deletions
diff --git a/Documentation/driver-api/firmware/introduction.rst b/Documentation/driver-api/firmware/introduction.rst
new file mode 100644
index 000000000..211cb44eb
--- /dev/null
+++ b/Documentation/driver-api/firmware/introduction.rst
@@ -0,0 +1,27 @@
+============
+Introduction
+============
+
+The firmware API enables kernel code to request files required
+for functionality from userspace, the uses vary:
+
+* Microcode for CPU errata
+* Device driver firmware, required to be loaded onto device
+ microcontrollers
+* Device driver information data (calibration data, EEPROM overrides),
+ some of which can be completely optional.
+
+Types of firmware requests
+==========================
+
+There are two types of calls:
+
+* Synchronous
+* Asynchronous
+
+Which one you use vary depending on your requirements, the rule of thumb
+however is you should strive to use the asynchronous APIs unless you also
+are already using asynchronous initialization mechanisms which will not
+stall or delay boot. Even if loading firmware does not take a lot of time
+processing firmware might, and this can still delay boot or initialization,
+as such mechanisms such as asynchronous probe can help supplement drivers.