summaryrefslogtreecommitdiff
path: root/payloads/libpayload/drivers/usb/TODO
diff options
context:
space:
mode:
authorPatrick Georgi <patrick.georgi@coresystems.de>2008-09-02 16:06:22 +0000
committerPatrick Georgi <patrick.georgi@coresystems.de>2008-09-02 16:06:22 +0000
commitd21f68bbd588f46c23066eb8d227b51e4823de41 (patch)
tree1c9c724d292b8de59599d98e8549177329953a12 /payloads/libpayload/drivers/usb/TODO
parent5ccfa1ac7994888f57c60b80fff80e350ab3f16c (diff)
downloadcoreboot-d21f68bbd588f46c23066eb8d227b51e4823de41.tar.xz
This patch adds USB capabilities to libpayload. It requires some
memalign implementation (eg. the one I sent yesterday). Features: - UHCI controller driver - UHCI root hub driver - USB MSC (Mass Storage Class) driver - skeleton of a USB HID driver (requires better interrupt transfer handling, which is TODO) - skeleton of a USB hub driver (needs several blank spots filled in, eg. power management. Again: TODO) OHCI and EHCI are not supported, though OHCI support should be rather easy as the stack provides reasonable abstractions (or so I hope). EHCI will probably be more complicated. Isochronous transfers (eg. webcams, audio stuff, ...) are not supported. They can be, but I doubt we'll have a reason for that in the boot environment. The MSC driver was tested against a couple of USB flash drives, and should be reasonably tolerant by now. But I probably underestimate the amount of bugs present in USB flash drives, so feedback is welcome. Signed-off-by: Patrick Georgi <patrick.georgi@coresystems.de> Acked-by: Jordan Crouse <jordan.crouse@amd.com> git-svn-id: svn://svn.coreboot.org/coreboot/trunk@3560 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
Diffstat (limited to 'payloads/libpayload/drivers/usb/TODO')
-rw-r--r--payloads/libpayload/drivers/usb/TODO22
1 files changed, 22 insertions, 0 deletions
diff --git a/payloads/libpayload/drivers/usb/TODO b/payloads/libpayload/drivers/usb/TODO
new file mode 100644
index 0000000000..1dfc9d40ab
--- /dev/null
+++ b/payloads/libpayload/drivers/usb/TODO
@@ -0,0 +1,22 @@
+- handle error conditions
+- handle disconnect more gracefully (ie. make calling layer aware that the device doesn't exist somehow)
+- usbhub:
+ - proper client enumeration (esp. detach)
+ - change detection
+ - power management
+- handle interrupts more cleverly:
+ create a new queue for the interrupt with a couple of TD sequences,
+ - each ending with "breadth first" flag
+ - linked as a chain
+ add that queue at the appropriate times in front of the default structure so the max latency is honored
+ - only one intr chain per framelist item, so it must be arranged appropriately
+ reads from usb device just look at "invalidated" tds and the results they got
+ handled tds get reactivated as a ring structure
+ - added as child of the oldest td
+ - queue header already dropped the td, so no issue there
+
+ this setup ensures that:
+ - the max latency of the device is honored
+ - the client knows the right order of the data
+ - there is no need for an interrupt handler
+ - but must be polled at least max latency * num tds times -> more tds = less time pressure