| Message ID | 20250405140002.3537411-1-linux@roeck-us.net (mailing list archive) |
|---|---|
| Headers | show |
| Series | Add property to support writing ERSTBA in high-low order | expand |
Hi Guenter, On 5/4/25 16:00, Guenter Roeck wrote: > This series is needed to support the USB interface on imx8mp-evk when > booting the Linux kernel. > > According to the XHCI specification, ERSTBA should be written in Low-High > order. The Linux kernel writes the high word first. This results in an > initialization failure. > > The following information is found in the Linux kernel commit log. > > [Synopsys]- The host controller was design to support ERST setting > during the RUN state. But since there is a limitation in controller > in supporting separate ERSTBA_HI and ERSTBA_LO programming, > It is supported when the ERSTBA is programmed in 64bit, > or in 32 bit mode ERSTBA_HI before ERSTBA_LO > > [Synopsys]- The internal initialization of event ring fetches > the "Event Ring Segment Table Entry" based on the indication of > ERSTBA_LO written. > > Add property to support writing the high word first. Enable it > for dwc3. > > ---------------------------------------------------------------- > Guenter Roeck (2): > hw: usb: xhci: Add property to support writing ERSTBA in high-low order > hw/usb/hcd-dwc3: Set erstba-hi-lo property What about using .impl.min_access_size = 8 instead? Could you try this patch, or provide me with a reproducer? -- >8 -- diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c index 64c3a23b9b7..bce61a287bf 100644 --- a/hw/usb/hcd-xhci.c +++ b/hw/usb/hcd-xhci.c @@ -3043,7 +3043,4 @@ static uint64_t xhci_runtime_read(void *ptr, hwaddr reg, switch (reg & 0x1f) { - case 0x00: /* IMAN */ - ret = intr->iman; - break; - case 0x04: /* IMOD */ - ret = intr->imod; + case 0x00: /* IMAN & IMOD */ + ret = deposit64(intr->iman, 32, 32, intr->imod); break; @@ -3052,13 +3049,7 @@ static uint64_t xhci_runtime_read(void *ptr, hwaddr reg, break; - case 0x10: /* ERSTBA low */ - ret = intr->erstba_low; + case 0x10: /* ERSTBA */ + ret = deposit64(intr->erstba_low, 32, 32, intr->erstba_high); break; - case 0x14: /* ERSTBA high */ - ret = intr->erstba_high; - break; - case 0x18: /* ERDP low */ - ret = intr->erdp_low; - break; - case 0x1c: /* ERDP high */ - ret = intr->erdp_high; + case 0x18: /* ERDP */ + ret = deposit64(intr->erdp_low, 32, 32, intr->erdp_high); break; @@ -3088,3 +3079,3 @@ static void xhci_runtime_write(void *ptr, hwaddr reg, switch (reg & 0x1f) { - case 0x00: /* IMAN */ + case 0x00: /* IMAN & IMOD */ if (val & IMAN_IP) { @@ -3094,23 +3085,19 @@ static void xhci_runtime_write(void *ptr, hwaddr reg, intr->iman |= val & IMAN_IE; + intr->imod = extract64(val, 32, 32); xhci_intr_update(xhci, v); break; - case 0x04: /* IMOD */ - intr->imod = val; - break; case 0x08: /* ERSTSZ */ - intr->erstsz = val & 0xffff; + intr->erstsz = extract64(val, 0, 16); break; - case 0x10: /* ERSTBA low */ + case 0x10: /* ERSTBA */ if (xhci->nec_quirks) { /* NEC driver bug: it doesn't align this to 64 bytes */ - intr->erstba_low = val & 0xfffffff0; + intr->erstba_low = extract64(val, 4, 28); } else { - intr->erstba_low = val & 0xffffffc0; + intr->erstba_low = extract64(val, 6, 26); } - break; - case 0x14: /* ERSTBA high */ - intr->erstba_high = val; + intr->erstba_high = extract64(val, 32, 32); xhci_er_reset(xhci, v); break; - case 0x18: /* ERDP low */ + case 0x18: /* ERDP */ if (val & ERDP_EHB) { @@ -3128,5 +3115,3 @@ static void xhci_runtime_write(void *ptr, hwaddr reg, } - break; - case 0x1c: /* ERDP high */ - intr->erdp_high = val; + intr->erdp_high = extract64(val, 32, 32); break; @@ -3216,2 +3201,3 @@ static const MemoryRegionOps xhci_runtime_ops = { .write = xhci_runtime_write, + .impl.min_access_size = 8, .valid.min_access_size = 4, --- Regards, Phil.
On 4/5/25 07:25, Philippe Mathieu-Daudé wrote: > Hi Guenter, > > On 5/4/25 16:00, Guenter Roeck wrote: >> This series is needed to support the USB interface on imx8mp-evk when >> booting the Linux kernel. >> >> According to the XHCI specification, ERSTBA should be written in Low-High >> order. The Linux kernel writes the high word first. This results in an >> initialization failure. >> >> The following information is found in the Linux kernel commit log. >> >> [Synopsys]- The host controller was design to support ERST setting >> during the RUN state. But since there is a limitation in controller >> in supporting separate ERSTBA_HI and ERSTBA_LO programming, >> It is supported when the ERSTBA is programmed in 64bit, >> or in 32 bit mode ERSTBA_HI before ERSTBA_LO >> >> [Synopsys]- The internal initialization of event ring fetches >> the "Event Ring Segment Table Entry" based on the indication of >> ERSTBA_LO written. >> >> Add property to support writing the high word first. Enable it >> for dwc3. >> >> ---------------------------------------------------------------- >> Guenter Roeck (2): >> hw: usb: xhci: Add property to support writing ERSTBA in high-low order >> hw/usb/hcd-dwc3: Set erstba-hi-lo property > > What about using .impl.min_access_size = 8 instead? > That would seem to be a bit excessive. The problem only affects the ERSTBA register. I don't see an indication that other registers are affected, or that all accesses would have to be 64 bit wide. The information above also suggests that the controller can operate in both 32-bit and 64-bit mode. > Could you try this patch, or provide me with a reproducer? > That is a bit too invasive for my liking, and it would affect all users, not just dwc3. I'll leave such changes to you. I'll cook up a minimal reproducer and point you to it. Thanks, Guenter
On 4/5/25 07:25, Philippe Mathieu-Daudé wrote: > Hi Guenter, > > On 5/4/25 16:00, Guenter Roeck wrote: >> This series is needed to support the USB interface on imx8mp-evk when >> booting the Linux kernel. >> >> According to the XHCI specification, ERSTBA should be written in Low-High >> order. The Linux kernel writes the high word first. This results in an >> initialization failure. >> >> The following information is found in the Linux kernel commit log. >> >> [Synopsys]- The host controller was design to support ERST setting >> during the RUN state. But since there is a limitation in controller >> in supporting separate ERSTBA_HI and ERSTBA_LO programming, >> It is supported when the ERSTBA is programmed in 64bit, >> or in 32 bit mode ERSTBA_HI before ERSTBA_LO >> >> [Synopsys]- The internal initialization of event ring fetches >> the "Event Ring Segment Table Entry" based on the indication of >> ERSTBA_LO written. >> >> Add property to support writing the high word first. Enable it >> for dwc3. >> >> ---------------------------------------------------------------- >> Guenter Roeck (2): >> hw: usb: xhci: Add property to support writing ERSTBA in high-low order >> hw/usb/hcd-dwc3: Set erstba-hi-lo property > > What about using .impl.min_access_size = 8 instead? > > Could you try this patch, or provide me with a reproducer? > You should find everything you need to reproduce the problem at http://server.roeck-us.net/qemu/xhci/ Please let me know if you need anything else. Thanks, Guenter
Am 5. April 2025 17:26:14 UTC schrieb Guenter Roeck <linux@roeck-us.net>: >On 4/5/25 07:25, Philippe Mathieu-Daudé wrote: >> Hi Guenter, >> >> On 5/4/25 16:00, Guenter Roeck wrote: >>> This series is needed to support the USB interface on imx8mp-evk when >>> booting the Linux kernel. >>> >>> According to the XHCI specification, ERSTBA should be written in Low-High >>> order. The Linux kernel writes the high word first. This results in an >>> initialization failure. >>> >>> The following information is found in the Linux kernel commit log. >>> >>> [Synopsys]- The host controller was design to support ERST setting >>> during the RUN state. But since there is a limitation in controller >>> in supporting separate ERSTBA_HI and ERSTBA_LO programming, >>> It is supported when the ERSTBA is programmed in 64bit, >>> or in 32 bit mode ERSTBA_HI before ERSTBA_LO >>> >>> [Synopsys]- The internal initialization of event ring fetches >>> the "Event Ring Segment Table Entry" based on the indication of >>> ERSTBA_LO written. >>> >>> Add property to support writing the high word first. Enable it >>> for dwc3. >>> >>> ---------------------------------------------------------------- >>> Guenter Roeck (2): >>> hw: usb: xhci: Add property to support writing ERSTBA in high-low order >>> hw/usb/hcd-dwc3: Set erstba-hi-lo property >> >> What about using .impl.min_access_size = 8 instead? >> >> Could you try this patch, or provide me with a reproducer? >> > >You should find everything you need to reproduce the problem at Hi Guenter, thanks for testing the new board, much appreciated. > >http://server.roeck-us.net/qemu/xhci/ I like your approach of pruning the device tree automatically: <http://server.roeck-us.net/qemu/xhci/patches/0002-imx8mp-evk-Remove-unimplemented-properties-and-nodes.patch> Would you mind if I upstream it with a few modifications like in <https://github.com/shentok/qemu/commits/upstream/imx8mp-test/> ? If yes, please let me know if I attribute your work there correctly. Best regards, Bernhard > >Please let me know if you need anything else. > >Thanks, >Guenter >
Hi Bernhard, On 4/5/25 12:28, Bernhard Beschow wrote: > > > Am 5. April 2025 17:26:14 UTC schrieb Guenter Roeck <linux@roeck-us.net>: >> On 4/5/25 07:25, Philippe Mathieu-Daudé wrote: >>> Hi Guenter, >>> >>> On 5/4/25 16:00, Guenter Roeck wrote: >>>> This series is needed to support the USB interface on imx8mp-evk when >>>> booting the Linux kernel. >>>> >>>> According to the XHCI specification, ERSTBA should be written in Low-High >>>> order. The Linux kernel writes the high word first. This results in an >>>> initialization failure. >>>> >>>> The following information is found in the Linux kernel commit log. >>>> >>>> [Synopsys]- The host controller was design to support ERST setting >>>> during the RUN state. But since there is a limitation in controller >>>> in supporting separate ERSTBA_HI and ERSTBA_LO programming, >>>> It is supported when the ERSTBA is programmed in 64bit, >>>> or in 32 bit mode ERSTBA_HI before ERSTBA_LO >>>> >>>> [Synopsys]- The internal initialization of event ring fetches >>>> the "Event Ring Segment Table Entry" based on the indication of >>>> ERSTBA_LO written. >>>> >>>> Add property to support writing the high word first. Enable it >>>> for dwc3. >>>> >>>> ---------------------------------------------------------------- >>>> Guenter Roeck (2): >>>> hw: usb: xhci: Add property to support writing ERSTBA in high-low order >>>> hw/usb/hcd-dwc3: Set erstba-hi-lo property >>> >>> What about using .impl.min_access_size = 8 instead? >>> >>> Could you try this patch, or provide me with a reproducer? >>> >> >> You should find everything you need to reproduce the problem at > > Hi Guenter, > > thanks for testing the new board, much appreciated. > >> >> http://server.roeck-us.net/qemu/xhci/ > > I like your approach of pruning the device tree automatically: <http://server.roeck-us.net/qemu/xhci/patches/0002-imx8mp-evk-Remove-unimplemented-properties-and-nodes.patch> Would you mind if I upstream it with a few modifications like in <https://github.com/shentok/qemu/commits/upstream/imx8mp-test/> ? If yes, please let me know if I attribute your work there correctly. > Please feel free to go ahead. Attribution is fine. Note that I had submitted a similar patch a couple of years ago; that was rejected with the argument that I should not use the dts file from the Linux kernel in the first place. That is why I did not bother to submit the patch myself. Anyway, just for reference: the inspiration for this change is from commit bf1da4b308 ("hw/arm/raspi4b: Temporarily disable unimplemented rpi4b devices"). Thanks, Guenter
On 4/5/25 12:28, Bernhard Beschow wrote: > > > Am 5. April 2025 17:26:14 UTC schrieb Guenter Roeck <linux@roeck-us.net>: >> On 4/5/25 07:25, Philippe Mathieu-Daudé wrote: >>> Hi Guenter, >>> >>> On 5/4/25 16:00, Guenter Roeck wrote: >>>> This series is needed to support the USB interface on imx8mp-evk when >>>> booting the Linux kernel. >>>> >>>> According to the XHCI specification, ERSTBA should be written in Low-High >>>> order. The Linux kernel writes the high word first. This results in an >>>> initialization failure. >>>> >>>> The following information is found in the Linux kernel commit log. >>>> >>>> [Synopsys]- The host controller was design to support ERST setting >>>> during the RUN state. But since there is a limitation in controller >>>> in supporting separate ERSTBA_HI and ERSTBA_LO programming, >>>> It is supported when the ERSTBA is programmed in 64bit, >>>> or in 32 bit mode ERSTBA_HI before ERSTBA_LO >>>> >>>> [Synopsys]- The internal initialization of event ring fetches >>>> the "Event Ring Segment Table Entry" based on the indication of >>>> ERSTBA_LO written. >>>> >>>> Add property to support writing the high word first. Enable it >>>> for dwc3. >>>> >>>> ---------------------------------------------------------------- >>>> Guenter Roeck (2): >>>> hw: usb: xhci: Add property to support writing ERSTBA in high-low order >>>> hw/usb/hcd-dwc3: Set erstba-hi-lo property >>> >>> What about using .impl.min_access_size = 8 instead? >>> >>> Could you try this patch, or provide me with a reproducer? >>> >> >> You should find everything you need to reproduce the problem at > > Hi Guenter, > > thanks for testing the new board, much appreciated. > In this context: Did you get the PCIe interface to work ? It instantiates for me, but interrupts don't get through. This is with the latest Linux kernel. Thanks, Guenter
Am 6. April 2025 01:31:49 UTC schrieb Guenter Roeck <linux@roeck-us.net>: >On 4/5/25 12:28, Bernhard Beschow wrote: >> >> >> Am 5. April 2025 17:26:14 UTC schrieb Guenter Roeck <linux@roeck-us.net>: >>> On 4/5/25 07:25, Philippe Mathieu-Daudé wrote: >>>> Hi Guenter, >>>> >>>> On 5/4/25 16:00, Guenter Roeck wrote: >>>>> This series is needed to support the USB interface on imx8mp-evk when >>>>> booting the Linux kernel. >>>>> >>>>> According to the XHCI specification, ERSTBA should be written in Low-High >>>>> order. The Linux kernel writes the high word first. This results in an >>>>> initialization failure. >>>>> >>>>> The following information is found in the Linux kernel commit log. >>>>> >>>>> [Synopsys]- The host controller was design to support ERST setting >>>>> during the RUN state. But since there is a limitation in controller >>>>> in supporting separate ERSTBA_HI and ERSTBA_LO programming, >>>>> It is supported when the ERSTBA is programmed in 64bit, >>>>> or in 32 bit mode ERSTBA_HI before ERSTBA_LO >>>>> >>>>> [Synopsys]- The internal initialization of event ring fetches >>>>> the "Event Ring Segment Table Entry" based on the indication of >>>>> ERSTBA_LO written. >>>>> >>>>> Add property to support writing the high word first. Enable it >>>>> for dwc3. >>>>> >>>>> ---------------------------------------------------------------- >>>>> Guenter Roeck (2): >>>>> hw: usb: xhci: Add property to support writing ERSTBA in high-low order >>>>> hw/usb/hcd-dwc3: Set erstba-hi-lo property >>>> >>>> What about using .impl.min_access_size = 8 instead? >>>> >>>> Could you try this patch, or provide me with a reproducer? >>>> >>> >>> You should find everything you need to reproduce the problem at >> >> Hi Guenter, >> >> thanks for testing the new board, much appreciated. >> > >In this context: Did you get the PCIe interface to work ? >It instantiates for me, but interrupts don't get through. >This is with the latest Linux kernel. Yeah, it works with Buildroot as described in the handbook. When I append `-netdev user,id=net0 -device virtio-net-pci,netdev=net0` on the cli I can `wget http://www.google.com` successfully. When I omit it there is no network connectivity. This is with a 6.6.23 vendor kernel. However, even with your USB patches applied, PCIe and USB are non-functional on the latest aarch64 Arch Linux kernel (v6.14 [1]): [ 21.102444] platform 32f10108.usb: deferred probe pending: platform: supplier 32f10000.blk-ctrl not ready [ 21.102914] platform 32f00000.pcie-phy: deferred probe pending: platform: supplier 32f10000.blk-ctrl not ready I suspect that some bits need to indicate stable PLLs or similar, but that needs further investigation. Best regards, Bernhard [1] <https://archlinuxarm.org/packages/aarch64/linux-aarch64> > >Thanks, >Guenter >
On 4/6/25 04:03, Bernhard Beschow wrote: > > > Am 6. April 2025 01:31:49 UTC schrieb Guenter Roeck <linux@roeck-us.net>: >> On 4/5/25 12:28, Bernhard Beschow wrote: >>> >>> >>> Am 5. April 2025 17:26:14 UTC schrieb Guenter Roeck <linux@roeck-us.net>: >>>> On 4/5/25 07:25, Philippe Mathieu-Daudé wrote: >>>>> Hi Guenter, >>>>> >>>>> On 5/4/25 16:00, Guenter Roeck wrote: >>>>>> This series is needed to support the USB interface on imx8mp-evk when >>>>>> booting the Linux kernel. >>>>>> >>>>>> According to the XHCI specification, ERSTBA should be written in Low-High >>>>>> order. The Linux kernel writes the high word first. This results in an >>>>>> initialization failure. >>>>>> >>>>>> The following information is found in the Linux kernel commit log. >>>>>> >>>>>> [Synopsys]- The host controller was design to support ERST setting >>>>>> during the RUN state. But since there is a limitation in controller >>>>>> in supporting separate ERSTBA_HI and ERSTBA_LO programming, >>>>>> It is supported when the ERSTBA is programmed in 64bit, >>>>>> or in 32 bit mode ERSTBA_HI before ERSTBA_LO >>>>>> >>>>>> [Synopsys]- The internal initialization of event ring fetches >>>>>> the "Event Ring Segment Table Entry" based on the indication of >>>>>> ERSTBA_LO written. >>>>>> >>>>>> Add property to support writing the high word first. Enable it >>>>>> for dwc3. >>>>>> >>>>>> ---------------------------------------------------------------- >>>>>> Guenter Roeck (2): >>>>>> hw: usb: xhci: Add property to support writing ERSTBA in high-low order >>>>>> hw/usb/hcd-dwc3: Set erstba-hi-lo property >>>>> >>>>> What about using .impl.min_access_size = 8 instead? >>>>> >>>>> Could you try this patch, or provide me with a reproducer? >>>>> >>>> >>>> You should find everything you need to reproduce the problem at >>> >>> Hi Guenter, >>> >>> thanks for testing the new board, much appreciated. >>> >> >> In this context: Did you get the PCIe interface to work ? >> It instantiates for me, but interrupts don't get through. >> This is with the latest Linux kernel. > > Yeah, it works with Buildroot as described in the handbook. When I append `-netdev user,id=net0 -device virtio-net-pci,netdev=net0` on the cli I can `wget http://www.google.com` successfully. When I omit it there is no network connectivity. This is with a 6.6.23 vendor kernel. > I had no luck with virtio-net-pci. virtio-pci works for me, but I can not get real PCI devices (such as nvme or scsi adapters) to work. > However, even with your USB patches applied, PCIe and USB are non-functional on the latest aarch64 Arch Linux kernel (v6.14 [1]): > > [ 21.102444] platform 32f10108.usb: deferred probe pending: platform: supplier 32f10000.blk-ctrl not ready > [ 21.102914] platform 32f00000.pcie-phy: deferred probe pending: platform: supplier 32f10000.blk-ctrl not ready > > I suspect that some bits need to indicate stable PLLs or similar, but that needs further investigation. > Hmm, I had that too, but then I found that it works for me with the latest upstream kernel. Try the patches at http://server.roeck-us.net/qemu/xhci/patches-pca/ to see if it helps. The PMIC (PCA9450) may have to be present. You might also need to check the configuration. I just tried with 6.14 again, and it works for me even without above patches. I played around with the configuration to get to that point, but I don't remember what exactly what I did to make it work (sorry). Guenter
Am 6. April 2025 15:30:42 UTC schrieb Guenter Roeck <linux@roeck-us.net>: >On 4/6/25 04:03, Bernhard Beschow wrote: >> >> >> Am 6. April 2025 01:31:49 UTC schrieb Guenter Roeck <linux@roeck-us.net>: >>> On 4/5/25 12:28, Bernhard Beschow wrote: >>>> >>>> >>>> Am 5. April 2025 17:26:14 UTC schrieb Guenter Roeck <linux@roeck-us.net>: >>>>> On 4/5/25 07:25, Philippe Mathieu-Daudé wrote: >>>>>> Hi Guenter, >>>>>> >>>>>> On 5/4/25 16:00, Guenter Roeck wrote: >>>>>>> This series is needed to support the USB interface on imx8mp-evk when >>>>>>> booting the Linux kernel. >>>>>>> >>>>>>> According to the XHCI specification, ERSTBA should be written in Low-High >>>>>>> order. The Linux kernel writes the high word first. This results in an >>>>>>> initialization failure. >>>>>>> >>>>>>> The following information is found in the Linux kernel commit log. >>>>>>> >>>>>>> [Synopsys]- The host controller was design to support ERST setting >>>>>>> during the RUN state. But since there is a limitation in controller >>>>>>> in supporting separate ERSTBA_HI and ERSTBA_LO programming, >>>>>>> It is supported when the ERSTBA is programmed in 64bit, >>>>>>> or in 32 bit mode ERSTBA_HI before ERSTBA_LO >>>>>>> >>>>>>> [Synopsys]- The internal initialization of event ring fetches >>>>>>> the "Event Ring Segment Table Entry" based on the indication of >>>>>>> ERSTBA_LO written. >>>>>>> >>>>>>> Add property to support writing the high word first. Enable it >>>>>>> for dwc3. >>>>>>> >>>>>>> ---------------------------------------------------------------- >>>>>>> Guenter Roeck (2): >>>>>>> hw: usb: xhci: Add property to support writing ERSTBA in high-low order >>>>>>> hw/usb/hcd-dwc3: Set erstba-hi-lo property >>>>>> >>>>>> What about using .impl.min_access_size = 8 instead? >>>>>> >>>>>> Could you try this patch, or provide me with a reproducer? >>>>>> >>>>> >>>>> You should find everything you need to reproduce the problem at >>>> >>>> Hi Guenter, >>>> >>>> thanks for testing the new board, much appreciated. >>>> >>> >>> In this context: Did you get the PCIe interface to work ? >>> It instantiates for me, but interrupts don't get through. >>> This is with the latest Linux kernel. >> >> Yeah, it works with Buildroot as described in the handbook. When I append `-netdev user,id=net0 -device virtio-net-pci,netdev=net0` on the cli I can `wget http://www.google.com` successfully. When I omit it there is no network connectivity. This is with a 6.6.23 vendor kernel. >> > >I had no luck with virtio-net-pci. virtio-pci works for me, but I can not get real PCI devices >(such as nvme or scsi adapters) to work. I now tested with the latest Buildroot recipe, changing to upstream kernel version 6.14 and using the defconfig. The `wget` command still works for me with virtio-net-pci. However, I can confirm that I need your xhci patches for the usb storage device to be detected. > >> However, even with your USB patches applied, PCIe and USB are non-functional on the latest aarch64 Arch Linux kernel (v6.14 [1]): >> >> [ 21.102444] platform 32f10108.usb: deferred probe pending: platform: supplier 32f10000.blk-ctrl not ready >> [ 21.102914] platform 32f00000.pcie-phy: deferred probe pending: platform: supplier 32f10000.blk-ctrl not ready >> >> I suspect that some bits need to indicate stable PLLs or similar, but that needs further investigation. >> > >Hmm, I had that too, but then I found that it works for me with the latest upstream >kernel. I have this issue with Arch Linux but not with Buildroot. Strange. Best regards, Bernhard >Try the patches at http://server.roeck-us.net/qemu/xhci/patches-pca/ >to see if it helps. The PMIC (PCA9450) may have to be present. > >You might also need to check the configuration. I just tried with 6.14 again, and >it works for me even without above patches. I played around with the configuration >to get to that point, but I don't remember what exactly what I did to make it work >(sorry). > >Guenter >
This series is needed to support the USB interface on imx8mp-evk when booting the Linux kernel. According to the XHCI specification, ERSTBA should be written in Low-High order. The Linux kernel writes the high word first. This results in an initialization failure. The following information is found in the Linux kernel commit log. [Synopsys]- The host controller was design to support ERST setting during the RUN state. But since there is a limitation in controller in supporting separate ERSTBA_HI and ERSTBA_LO programming, It is supported when the ERSTBA is programmed in 64bit, or in 32 bit mode ERSTBA_HI before ERSTBA_LO [Synopsys]- The internal initialization of event ring fetches the "Event Ring Segment Table Entry" based on the indication of ERSTBA_LO written. Add property to support writing the high word first. Enable it for dwc3. ---------------------------------------------------------------- Guenter Roeck (2): hw: usb: xhci: Add property to support writing ERSTBA in high-low order hw/usb/hcd-dwc3: Set erstba-hi-lo property hw/usb/hcd-dwc3.c | 1 + hw/usb/hcd-xhci.c | 8 +++++++- hw/usb/hcd-xhci.h | 1 + 3 files changed, 9 insertions(+), 1 deletion(-)