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-rw-r--r--Documentation/firmware_class/README26
1 files changed, 17 insertions, 9 deletions
diff --git a/Documentation/firmware_class/README b/Documentation/firmware_class/README
index 7eceaff63f5f..815b711bcd85 100644
--- a/Documentation/firmware_class/README
+++ b/Documentation/firmware_class/README
@@ -18,32 +18,40 @@
18 High level behavior (mixed): 18 High level behavior (mixed):
19 ============================ 19 ============================
20 20
21 kernel(driver): calls request_firmware(&fw_entry, $FIRMWARE, device) 21 1), kernel(driver):
22 22 - calls request_firmware(&fw_entry, $FIRMWARE, device)
23 userspace: 23 - kernel searchs the fimware image with name $FIRMWARE directly
24 in the below search path of root filesystem:
25 "/lib/firmware/updates/" UTS_RELEASE,
26 "/lib/firmware/updates",
27 "/lib/firmware/" UTS_RELEASE,
28 "/lib/firmware"
29 - If found, goto 7), else goto 2)
30
31 2), userspace:
24 - /sys/class/firmware/xxx/{loading,data} appear. 32 - /sys/class/firmware/xxx/{loading,data} appear.
25 - hotplug gets called with a firmware identifier in $FIRMWARE 33 - hotplug gets called with a firmware identifier in $FIRMWARE
26 and the usual hotplug environment. 34 and the usual hotplug environment.
27 - hotplug: echo 1 > /sys/class/firmware/xxx/loading 35 - hotplug: echo 1 > /sys/class/firmware/xxx/loading
28 36
29 kernel: Discard any previous partial load. 37 3), kernel: Discard any previous partial load.
30 38
31 userspace: 39 4), userspace:
32 - hotplug: cat appropriate_firmware_image > \ 40 - hotplug: cat appropriate_firmware_image > \
33 /sys/class/firmware/xxx/data 41 /sys/class/firmware/xxx/data
34 42
35 kernel: grows a buffer in PAGE_SIZE increments to hold the image as it 43 5), kernel: grows a buffer in PAGE_SIZE increments to hold the image as it
36 comes in. 44 comes in.
37 45
38 userspace: 46 6), userspace:
39 - hotplug: echo 0 > /sys/class/firmware/xxx/loading 47 - hotplug: echo 0 > /sys/class/firmware/xxx/loading
40 48
41 kernel: request_firmware() returns and the driver has the firmware 49 7), kernel: request_firmware() returns and the driver has the firmware
42 image in fw_entry->{data,size}. If something went wrong 50 image in fw_entry->{data,size}. If something went wrong
43 request_firmware() returns non-zero and fw_entry is set to 51 request_firmware() returns non-zero and fw_entry is set to
44 NULL. 52 NULL.
45 53
46 kernel(driver): Driver code calls release_firmware(fw_entry) releasing 54 8), kernel(driver): Driver code calls release_firmware(fw_entry) releasing
47 the firmware image and any related resource. 55 the firmware image and any related resource.
48 56
49 High level behavior (driver code): 57 High level behavior (driver code):