[RFC] PCI: skip pci host bridge as early as possible
Antony Pavlov
antonynpavlov at gmail.com
Tue Jun 16 12:45:34 PDT 2015
On Tue, 16 Jun 2015 21:21:36 +0200
Lucas Stach <dev at lynxeye.de> wrote:
> Am Dienstag, den 16.06.2015, 22:22 +0300 schrieb Antony Pavlov:
> > On Tue, 16 Jun 2015 21:04:47 +0200
> > Lucas Stach <dev at lynxeye.de> wrote:
> >
> > > Hi Antony,
> > >
> > > I don't think ignoring the host bridge is the right thing to do in the
> > > first place and unfortunately I'm unable to reproduce your problem.
> >
> > What is your qemu version?
> >
> QEMU emulator version 2.1.3 (qemu-2.1.3-7.fc21)
Hmm, 2.1.3 is from "old and stable" branch.
I use latest qemu release from debian:
$ qemu-system-mips --version
QEMU emulator version 2.3.0 (Debian 1:2.3+dfsg-6a), Copyright (c) 2003-2008 Fabrice Bellard
AFAIR qemu-2.2.x has the same qemu malta PCI problem.
>
> >
> > Anyway linux PCI initialization code differ from barebox PCI initialization code:
> > linux code tries to revert PBAR contents after determening PBAR sizes.
> >
> > Here is the patch that adds linux PCI setup behaviour to barebox:
> >
> Does this fix your problem?
no.
>
> Linux puts back the previous content as it tries to keep as much as
> possible from a potentially existing firmware configuration. It doesn't
> make too much sense in a bootloader that is essentially the firmware
> itself. But if it fixes the problem you are seeing we might still
> include something like that.
>
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index 7953c55..b60bd5b 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -141,9 +141,12 @@ static void setup_device(struct pci_dev *dev, int max_bar)
> >
> > for (bar = 0; bar < max_bar; bar++) {
> > resource_size_t last_addr;
> > + u32 l;
> >
> > + pci_read_config_dword(dev, PCI_BASE_ADDRESS_0 + bar * 4, &l);
> > pci_write_config_dword(dev, PCI_BASE_ADDRESS_0 + bar * 4, 0xfffffffe);
> > pci_read_config_dword(dev, PCI_BASE_ADDRESS_0 + bar * 4, &mask);
> > + pci_write_config_dword(dev, PCI_BASE_ADDRESS_0 + bar * 4, l);
> >
> > if (mask == 0 || mask == 0xffffffff) {
> > pr_debug("pbar%d set bad mask\n", bar);
> >
> >
> >
> > > Am Dienstag, den 09.06.2015, 22:51 +0300 schrieb Antony Pavlov:
> > > > The barebox' pci_scan_bus() function first tries to setup GT64120
> > > > host bridge BARs but fails:
> > > >
> > > > barebox:/ dmesg
> > > > pci: pci_scan_bus for bus 0
> > > > pci: last_io = 0x18000000, last_mem = 0x10000000, last_mem_pref = 0x00000000
> > > > pci: class = 00000600, hdr_type = 00000000
> > > > pci: 00:00 [11ab:4620]
> > > > pci: pbar0: mask=00000008 NP memory 0 bytes
> > > > pci: pbar1: mask=01000008 NP memory -16777216 bytes
> > > > pci: pbar2: mask=1c000000 NP memory -469762048 bytes
> > > > pci: BAR does not fit within bus np-mem res
> > > > pci: skip pci host bridge
> > > >
> > > I can reproduce up until here. But the messages suggest that barebox is
> > > in fact skipping the BAR configuration, so this isn't really a problem.
> > >
> > > This might be improved by checking for invalid BAR sizes before trying
> > > to fit them.
> > >
> > > > so PCI host bridge and all discovered devices are misconfigured, e.g.
> > > > miitool can't find rtl8139 emulated NIC tranceiver:
> > > >
> > > > rtl8139_eth pci-10ec:8139.0: rtl8139 (rev 20) at 90: 0200 (base=8f000000)
> > > > rtl8139_eth pci-10ec:8139.0: enabling bus mastering
> > > > ...
> > > > barebox:/ miitool
> > > > miibus0: registered phy as /dev/phy0
> > > > phy0: eth0: No MII transceiver present!.
> > > >
> > >
> > > Works for me:
> > >
> > > barebox:/ miitool
> > > miibus0: registered phy as /dev/phy0
> > > phy0: eth0: no autonegotiation, 100baseTx-FD flow-control, link ok
> > >
> > > > Here is linux-3.19 GT64120 host bridge discovery log:
> > > >
> > > > PCI host bridge to bus 0000:00
> > > > pci_bus 0000:00: root bus resource [mem 0x10000000-0x17ffffff]
> > > > pci_bus 0000:00: root bus resource [io 0x1000-0x1fffff]
> > > > pci_bus 0000:00: No busn resource found for root bus, will use [bus 00-ff]
> > > > pci 0000:00:00.0: [Firmware Bug]: reg 0x14: invalid BAR (can't size)
> > > > pci 0000:00:00.0: [Firmware Bug]: reg 0x18: invalid BAR (can't size)
> > > > pci 0000:00:00.0: [Firmware Bug]: reg 0x1c: invalid BAR (can't size)
> > > > pci 0000:00:00.0: [Firmware Bug]: reg 0x20: invalid BAR (can't size)
> > > > pci 0000:00:00.0: [Firmware Bug]: reg 0x24: invalid BAR (can't size)
> > > >
> > > > The appropriate lspci -v log:
> > > >
> > > > 00:00.0 Host bridge: Marvell Technology Group Ltd. GT-64120/64120A/64121A System Controller (rev 10)
> > > > Subsystem: Red Hat, Inc Device 1100
> > > > Control: I/O- Mem- BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
> > > > Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
> > > > Interrupt: pin A routed to IRQ 0
> > > > Subsystem: Red Hat, Inc Device 1100
> > > > Flags: medium devsel
> > > > Memory at <unassigned> (32-bit, prefetchable) [disabled]
> > > > Memory at <ignored> (32-bit, prefetchable) [disabled]
> > > > Memory at <ignored> (32-bit, non-prefetchable) [disabled]
> > > > Memory at <ignored> (32-bit, non-prefetchable) [disabled]
> > > > Memory at <ignored> (32-bit, non-prefetchable) [disabled]
> > > > I/O ports at <ignored> [disabled]
> > > >
> > > > It looks like qemu-system-mips does not fully emulates GT64120 host
> > > > bridge BARs so skipping host bridge BAR's setup fixes qemu-malta
> > > > problem. But can we skip host bridge BAR's setup for other targets?
> > > >
> > > > Signed-off-by: Antony Pavlov <antonynpavlov at gmail.com>
> > > > ---
> > > > drivers/pci/pci.c | 10 +++++-----
> > > > 1 file changed, 5 insertions(+), 5 deletions(-)
> > > >
> > > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > > > index 3a0e7a5..7953c55 100644
> > > > --- a/drivers/pci/pci.c
> > > > +++ b/drivers/pci/pci.c
> > > > @@ -331,6 +331,11 @@ unsigned int pci_scan_bus(struct pci_bus *bus)
> > > > pr_debug("%02x:%02x [%04x:%04x]\n", bus->number, dev->devfn,
> > > > dev->vendor, dev->device);
> > > >
> > > > + if (class == PCI_CLASS_BRIDGE_HOST) {
> > > > + pr_debug("skip pci host bridge\n");
> > > > + continue;
> > > > + }
> > > > +
> > > > switch (hdr_type & 0x7f) {
> > > > case PCI_HEADER_TYPE_NORMAL:
> > > > if (class == PCI_CLASS_BRIDGE_PCI)
> > > > @@ -391,11 +396,6 @@ unsigned int pci_scan_bus(struct pci_bus *bus)
> > > > bus->number, dev->devfn, dev->vendor, dev->device, class, hdr_type);
> > > > continue;
> > > > }
> > > > -
> > > > - if (class == PCI_CLASS_BRIDGE_HOST) {
> > > > - pr_debug("skip pci host bridge\n");
> > > > - continue;
> > > > - }
> > > > }
> > > >
> > > > /*
> > >
> > >
> >
> >
>
>
--
--
Best regards,
Antony Pavlov
More information about the barebox
mailing list