as proposed on tech-kern@.
While all DMA memory used in the USB framework is mapped BUS_DMAMAP_COHERENT
(including data memory, which is memcpy'd from/to USB-private buffers),
the CPU can reorder loads or stores from/to main memory, causing the
controller to have an incoherent view of the DMA descriptors lists for a
short time. bus_dmamap_sync() should contain memory barriers that prevents
the CPU from reordering load/store. Note that BUS_DMAMAP_COHERENT is
still required for the DMA descriptor lists - these can't work properly
with software cache coherency.
This fixes "host controller process error/host controller halted" errors
I'm occasionally seeing with a umodem device on uhci on x86.
Thanks to Michael Lorenz for testing it on his O2, and Izumi Tsutsui on
his Cobalt Qube 2700.
- for structure fields that are conditionally present,
make those fields always present.
- for functions which are conditionally inline, make them never inline.
- remove some other functions which are conditionally defined but
don't actually do anything anymore.
- make a lock-debugging function conditional on only LOCKDEBUG.
as discussed on tech-kern some time back.
in the wanted bus_dma space. If an allocation fails during operation
(i.e. when hotplugging an umass device), fall back to using the reserve.
The amount can be configured as USB_MEM_RESERVE. The default value is
256k.
Ideally, there would be a way to steal pages in the desired area from
UVM, but that's far more complicated, and this is not intrusive, plus
it works.
It means that we continously poll USB devices that have a pending transfer
instead of polling just once every ms. This speeds up some transfers
at the expense of using more PCI bandwidth.
Make each xfer have its own intr_info. This is necessary if we want
to queue multiple xfers on an endpoint. This should get rid of the
(mostly harmless) DIAGNOSTICs about intr_infos (not) being done.
Change (again!) how xfers are aborted. Aborting a TD is a nightmare
on the braindead UHCI controller. (Unless you stop the HC, thereby
losing isoc traffic.) Hopefully I got it right this time.
timeout()/untimeout() API:
- Clients supply callout handle storage, thus eliminating problems of
resource allocation.
- Insertion and removal of callouts is constant time, important as
this facility is used quite a lot in the kernel.
The old timeout()/untimeout() API has been removed from the kernel.
by Nick Hibma):
use NULL not 0
declare all local definitions static
rename s/usbd_request/usbd_xfer/ s/reqh/xfer/
rename s/r/err/
use implicit test for no err
KNF
