RPi4B: emmc2bus dma-range handling does not track the boot-time-FDT (u-boot based booting)

Mark Millard marklmi at yahoo.com
Fri Oct 9 03:06:14 UTC 2020


On 2020-Oct-8, at 06:27, Klaus Cucinauomo <maciphone2 at googlemail.com> wrote:

>> Am 08.10.2020 um 11:01 schrieb Mark Millard via freebsd-arm <freebsd-arm at freebsd.org>:
>> 
>> 
>> The old u-boot/DTB combination in use does not have emmc2bus.
>> And, even if it did, FreeBSD would not use ……….
> 
> … and the new 2020.10- combinations will even be more annoying…
> While I meanwhile e.g. could boot the 4GB off of xhci, it hangs in DeviceTree,
> Depending on GUESSED ;-) combinations and DeviceTree-patches in src .
> There have to be necessary  adjustments which are even not yet upstreamed in u-boot 
> (depending on hw-revisions)…and so on ...
> I doubt that anyone really will take explicitly time consuming care of all that annoying RPI4-crap.
> I don't see any other way than targeting minimum 1 developer(better more) ONLY to the RPI-platform 
> for a  time period… other than leaving it crappy as is and to be happy that it nevertheless 
> is a working fbsd-gadget :-)


Summary of probable-cause finding: u-boot 2020.10 is
expecting:

compatible = "brcm,generic-xhci"

instead of what seems to be in files that are in use
by FreeBSD:

compatible = "generic-xhci"

(I've no clue what all the other differences in the .dtb
file contents might be.)



The details of what I learned that reached that status . . .

I updated my ports environment on a RPi4 to build the final 2020.10 u-boot
for the RPi4. I then built it and replaced the u-boot.bin on the microsd
card that I boot with via the FreeBSD kernel being from that microsd card
but later stages being from the USB3 SSD. I did not update anything else.
So: still an older .dtb file.

That 8 GiByte RPi4B context booted just fine.

I then rebooted and had it stop in u-boot and looked around just a little
bit.

U-Boot 2020.10 (Oct 09 2020 - 00:51:29 +0000)

DRAM:  7.9 GiB
RPI 4 Model B (0xd03114)
MMC:   mmc at 7e300000: 1, emmc2 at 7e340000: 0
Loading Environment from FAT... In:    serial
Out:   vidconsole
Err:   vidconsole
Net:   eth0: ethernet at 7d580000
PCIe BRCM: link up, 5.0 Gbps x1 (SSC)
starting USB...
Bus xhci_pci: probe failed, error -110
No working controllers found
Hit any key to stop autoboot:  0 

So it reproted the problem above. Yet . . .

U-Boot> pci 0
Scanning PCI devices on bus 0
BusDevFun  VendorId   DeviceId   Device Class       Sub-Class
_____________________________________________________________
00.00.00   0x14e4     0x2711     Bridge device           0x04

U-Boot> pci 1   
Scanning PCI devices on bus 1
BusDevFun  VendorId   DeviceId   Device Class       Sub-Class
_____________________________________________________________
01.00.00   0x1106     0x3483     Serial bus controller   0x03

So it does see the xHCI on the pci bus despite the
"Bus xhci_pci: probe failed, error -110". -110 looks
to be -ETIMEDOUT .

Looking at the v2020.10/drivers/usb/host/xhci-pci.c source
code shows that the xhci_pci driver has:

. . .
static const struct udevice_id xhci_pci_ids[] = {
	{ .compatible = "xhci-pci" },
	{ }
};

U_BOOT_DRIVER(xhci_pci) = {
	.name	= "xhci_pci",
	.id	= UCLASS_USB,
	.probe = xhci_pci_probe,
	.remove = xhci_deregister,
	.of_match = xhci_pci_ids,
	.ops	= &xhci_usb_ops,
	.platdata_auto_alloc_size = sizeof(struct usb_platdata),
	.priv_auto_alloc_size = sizeof(struct xhci_ctrl),
	.flags	= DM_FLAG_ALLOC_PRIV_DMA,
};

static struct pci_device_id xhci_pci_supported[] = {
	{ PCI_DEVICE_CLASS(PCI_CLASS_SERIAL_USB_XHCI, ~0) },
	{},
};

U_BOOT_PCI_DEVICE(xhci_pci, xhci_pci_supported);

(It looks like the above driver is used as the default
driver if no explicit match is found. It has been around
for years.)


But, in the past when I showed the likes of fdt print /
or translation to a .dts file, it did not have "xhci-pci"
in compatible but had "generic-xhci" instead, such as:

                xhci at 7e9c0000 {
                        compatible = "generic-xhci";
                        status = "disabled";
                        reg = <0x00000000 0x7e9c0000 0x00000000 0x00100000>;
                        interrupts = <0x00000000 0x000000b0 0x00000004>;
                        phandle = <0x000000d3>;
                };

For reference, for FreeBSD there is:

# grep -ri "xhci-pci" /usr/src/sys/ | more
# grep -ri "generic-xhci" /usr/src/sys/ | more
/usr/src/sys/dev/usb/controller/generic_xhci_fdt.c:     {"generic-xhci",                true},
/usr/src/sys/gnu/dts/arm/bcm-nsp.dtsi:                  compatible = "generic-xhci";
/usr/src/sys/gnu/dts/arm/bcm5301x.dtsi:                         compatible = "generic-xhci";
/usr/src/sys/gnu/dts/arm64/broadcom/stingray/stingray-usb.dtsi:                 compatible = "generic-xhci";
/usr/src/sys/gnu/dts/arm64/broadcom/stingray/stingray-usb.dtsi:                 compatible = "generic-xhci";
/usr/src/sys/gnu/dts/arm64/marvell/armada-37xx.dtsi:                            "generic-xhci";
/usr/src/sys/gnu/dts/arm64/marvell/armada-cp11x.dtsi:                   "generic-xhci";
/usr/src/sys/gnu/dts/arm64/marvell/armada-cp11x.dtsi:                   "generic-xhci";

That FreeBSD generic_xhci_fdt.c match is from:

static struct ofw_compat_data compat_data[] = {
        {"marvell,armada-380-xhci",     true},
        {"marvell,armada3700-xhci",     true},
        {"marvell,armada-8k-xhci",      true},
        {"generic-xhci",                true},
        {NULL,                          false}
};

(End for-reference.)

There is another driver in u-boot 2020.10, one that
does mention "generic-" for xhci in
drivers/usb/host/xhci-brcm.c :

static const struct udevice_id xhci_brcm_ids[] = {
        { .compatible = "brcm,generic-xhci" },
        { }
};

U_BOOT_DRIVER(usb_xhci) = {
        .name                           = "xhci_brcm",
        .id                             = UCLASS_USB,
        .probe                          = xhci_brcm_probe,
        .remove                         = xhci_brcm_deregister,
        .ops                            = &xhci_usb_ops,
        .of_match                       = xhci_brcm_ids,
        .platdata_auto_alloc_size       = sizeof(struct brcm_xhci_platdata),
        .priv_auto_alloc_size           = sizeof(struct xhci_ctrl),
        .flags                          = DM_FLAG_ALLOC_PRIV_DMA,
};

It is a new driver as of around 6 months ago and so is likely
the one created for the RPi4B context.

(Note the usb_xhci vs. xhci_brcm distinct namings of
the driver.)


The .dtb files that I use for uefi/ACPI booting of FreeBSD
and for u-boot based booting of ubuntu 2010.04.1 also use
"generic-xhci", no "brcm," invovled.

It seems that .dtb files that the u-boot folks expect for
the RPi4B are vintages/variations that have compatible
listing: "brcm,generic-xhci" .

If one finds a .dtb with such, it might be close to what
they were testing. With such a file, finding other
differences with the .dtb files currently in use with
FreeBSD could be done.

I hope that the above helps.

===
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)



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