[coreboot] xHCI support for x86
jpi at sysgo.com
Fri Dec 2 14:29:47 CET 2016
Sorry for delay, but i have to understand a lot things before answering (:
On 23/11/2016 14:25, Nico Huber wrote:
> On 23.11.2016 11:09, Pitrolle Jean-Jacques wrote:
>> Hello *,
>> I try to integrate coreboot *libpayload usb stack* in a custom binary
>> for x86.
>> I already succeed integration of *ehci* for *qemu* and *core 2 duo*
>> But things seems to be not so easy for *xhci*.
>> When I try to run coreboot master branch (with hash 8bf3f7a) on qemu
>> (version 2.7.0)
>> with following line :
>> % qemu-system-x86_64 -bios build/coreboot.rom -serial stdio -drive
>> if=none,id=usbstick,file=/tmp/qemu_usb.disk -usb -device
>> nec-usb-xhci,id=xhci -device usb-storage,bus=xhci.0,drive=usbstick
>> I get these output lines concerning xHCI controller (nec-usb-xhci) :
>> 00:04.0 0194:1033.0 xHCI controller
>> xhci_init: regbase: 0xfe070000
>> xhci_init: caplen: 0x40
>> xhci_init: rtsoff: 0x1000
>> xhci_init: dboff: 0x2000
>> xhci_init: hciversion: 0.0
>> xhci_init: Unsupported xHCI version
>> The same result is reached with qemu-system-i386...
>> Is it the expected result on qemu?
> it looks odd to me. We wrote the ancestor of this xHCI driver against
> qemu but stopped testing it when we switched to real hardware. I would
> have expected an hciversion around 0.9*. The libpayload driver currently
> checks for hciversion > 0.96. The values above hciversion look sane, so
> I suspect qemu to tell a bad version.
The functions that access virtual xHCI only works for 4 bytes access.
For example, if i read capability register
- access to offset 0, size access 4 bytes : 1000040
- access to offset 2, size access 2 bytes : 00 *wrong value*
- access to offset 2 and 3, size access 1 bytes: 0 - 0 *wrong value*
The 8bit/16bit reads are not properly honored.
Moreover, the previous *used* qemu (2.7.0) compiled by my own with
seems to be broken (i don't go too deep in investigation right now)..
Everything is ok with *upstream* qemu (hash : 00227f - version : 2.7.91
>> I don't have any motherboard supported by coreboot, so I try a custom
>> binary on
> How is this custom binary build? In which environment does it run? It's
> hard to make assumptions about the driver without knowing the details.
>> a *Xeon* processor (processor D-1500).
> So you are using the xHCI controller built into the SoC? or an extension
I use xHCI controller built into SoC.
>> The xHCI version is supported (hciversion: 1.0) but things turn bad when
>> xHCI controller i.e xhci->opreg->usbcmd |= USBCMD_RS in *xhci_start* :
>> the program hangs...
>> The registers usbcmd and usbsts before this command seems to have proper
>> values (a usb key
>> is connected.)
>> xhci_start - usbcmd:0 - usbsts:11
>> This seems to be related to interrupter configuration. When I comment
>> out the two lines
>> in *xhci_reinit*
>> xhci->hcrreg->intrrs.erstba_lo = virt_to_phys(xhci->ev_ring_table);
> I'd suspect that the address returned by virt_to_phys() is wrong or not
> accessible by the controller.
Hmm, seems not as it work properly with rigth qemu version.
>> xhci->hcrreg->intrrs.erstba_hi = 0;
> Are you sure it's a 32-bit address?
I used a 32 bits compiler, so i expect it..
Do i need to setup something else (in bios for example)?
>> xhci_start works as expected i.e not hangs.
>> But the sequence following with *NOOP* to test command ring and event
>> ring mechanism fails.
>> NOOP run #0
>> Transfer TRB (@0x8051700):
>> PTR_L 0x00000000
>> PTR_H 0x00000000
>> STATUS 0x00000000
>> CNTRL 0x00005c00
>> TL 0x0000
>> TDS 0x0000
>> C 0x0000
>> ISP 0x0000
>> CH 0x0000
>> IOC 0x0000
>> IDT 0x0000
>> TT 0x0017
>> DIR 0x0000
>> Command 23 (@0x8051700)
>> Warning: Timed out waiting for TRB_EV_CMD_CMPL.
>> Command ring is running
>> As I understand it is mandatory to have the first interrupter configure
>> to manage
>> at least one event ring (4.9.4 Event Ring Management - eXtensible Host
>> Controller Interface
>> Revision 1.1).
>> Does someone succeed with xHCI support for x86 board?
>> Did I miss something concerning xHCI configuration?
> It's working in coreboot payloads in many production systems.
With values read from registers dboff (0x3000) and rtsoff (0x2000) and
not values provided in
datasheet (*wrong values*) write to USBCMD register to start controller
works as expected : there
is no weird hanging.
The problem came from *extended capability register* xCAP. In my case it
is mandatory to release xHCI
controller from BIOS. "HC BIOS Owned Semaphore" must be set to 0 and "HC
OS Owned Semaphore" must
be set to 1.
So things go ahead :
- enumeration of a usb-key on *qemu* works properly.
- *but* i still have a problem on Xeon (Broadwell-DE SoC).
The problem concerns event ring during enable slot command :
Command 9 (@0x8052240)
Transfer TRB (@0x8052240):
_____address:8052240 phys:d79240 low:0 high:0 s:0 c:8052240
The dump of TRB is located in *xhci_post_command* just after xhci_debug
and before TRB_SET.
The line "_____address:8052240 phys:d79240 low:0 high:0 s:0 c:8052240"
in *xhci_wait_for_command_done* just before while
(xhci_wait_for_event_type(xhci, TRB_EV_CMD_CMPL, &timeout_us))
Do i need to flush cache if event and command rings are located in
I use a custom allocator and for now it is not possible to allocate
memory as "uncachable"
Is is possible to check proper initialization of event and command rings?
I see nothing relevant in xHCI standard concerning this.
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