1 ============ 2 Introduction 3 ============ 4 5 The firmware API enables kernel code to request files required 6 for functionality from userspace, the uses vary: 7 8 * Microcode for CPU errata 9 * Device driver firmware, required to be loaded onto device 10 microcontrollers 11 * Device driver information data (calibration data, EEPROM overrides), 12 some of which can be completely optional. 13 14 Types of firmware requests 15 ========================== 16 17 There are two types of calls: 18 19 * Synchronous 20 * Asynchronous 21 22 Which one you use vary depending on your requirements, the rule of thumb 23 however is you should strive to use the asynchronous APIs unless you also 24 are already using asynchronous initialization mechanisms which will not 25 stall or delay boot. Even if loading firmware does not take a lot of time 26 processing firmware might, and this can still delay boot or initialization, 27 as such mechanisms such as asynchronous probe can help supplement drivers.
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.