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SubjectRe: [PATCH v6 0/2] PCI: dwc: Add support for 64-bit MSI target addresses
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On 2023-01-31 12:29, Evgenii Shatokhin wrote:
> Hi,
>
> On 26.08.2022 02:54, Will McVicker wrote:
>> Hi All,
>>
>> I've update patch 2/2 to address Robin's suggestions. This includes:
>>
>>   * Dropping the while-loop for retrying with a 64-bit mask in favor of
>>     retrying within the error if-statement.
>>   * Using an int for the DMA mask instead of a bool and ternary
>> operation.
>>
>> Thanks again for the reviews and sorry for the extra revision today!
>> Hopefully this is the last one :) If not, I'd be fine to submit patch 1/2
>> without 2/2 to avoid resending patch 1/2 for future revisions of patch
>> 2/2
>> (unless I don't need to do that anyway).
>
> The first patch of the series made it into the mainline kernel, but, it
> seems, the second one ("PCI: dwc: Add support for 64-bit MSI target
> address") did not. As of 6.2-rc6, it is still missing.
>
> Was it intentionally dropped because of some issues or, perhaps, just by
> accident? If it was by accident, could you please queue it for inclusion
> into mainline again?

Yes, it was dropped due to the PCI_MSI_FLAGS_64BIT usage apparently
being incorrect, and some other open debate (which all happened on the
v5 thread):

https://lore.kernel.org/linux-pci/YzVTmy9MWh+AjshC@lpieralisi/

The DMA mask issues have now been sorted out, so you, or Will, or anyone
else interested should be free to rework this on top of linux-next
(although at this point, more realistically on top of 6.3-rc1 in a few
weeks).

Thanks,
Robin.

> Support for 64-bit MSI target addresses is needed for some of our SoCs.
> I ran into a situation when there was no available RAM in ZONE_DMA32
> during initialization of PCIe host. Hence, dmam_alloc_coherent() failed
> in dw_pcie_msi_host_init() and initialization failed with -ENOMEM:
>
> [    0.374834] dw-pcie 4000000.pcie0: host bridge /soc/pcie0@4000000
> ranges:
> [    0.375813] dw-pcie 4000000.pcie0:      MEM
> 0x0041000000..0x004fffffff -> 0x0041000000
> [    0.376171] dw-pcie 4000000.pcie0:   IB MEM
> 0x0400000000..0x07ffffffff -> 0x0400000000
> [    0.377914] dw-pcie 4000000.pcie0: Failed to alloc and map MSI data
> [    0.378191] dw-pcie 4000000.pcie0: Failed to initialize host
> [    0.378255] dw-pcie: probe of 4000000.pcie0 failed with error -12
>
> Mainline kernel 6.2-rc6 was used in that test.
>
> The hardware supports 64-bit target addresses, so the patch "PCI: dwc:
> Add support for 64-bit MSI target address" should help with this
> particular failure.
>
>
>>
>> Thanks,
>> Will
>>
>> Will McVicker (2):
>>    PCI: dwc: Drop dependency on ZONE_DMA32
>>
>> v6:
>>   * Retrying DMA allocation with 64-bit mask within the error
>> if-statement.
>>   * Use an int for the DMA mask instead of a bool and ternary operation.
>>
>> v5:
>>   * Updated patch 2/2 to first try with a 32-bit DMA mask. On failure,
>>     retry with a 64-bit mask if supported.
>>
>> v4:
>>   * Updated commit descriptions.
>>   * Renamed msi_64b -> msi_64bit.
>>   * Dropped msi_64bit ternary use.
>>   * Dropped export of dw_pcie_msi_capabilities.
>>
>> v3:
>>    * Switched to a managed DMA allocation.
>>    * Simplified the DMA allocation cleanup.
>>    * Dropped msi_page from struct dw_pcie_rp.
>>    * Allocating a u64 instead of a full page.
>>
>> v2:
>>    * Fixed build error caught by kernel test robot
>>    * Fixed error handling reported by Isaac Manjarres
>>   PCI: dwc: Add support for 64-bit MSI target address
>>
>>   .../pci/controller/dwc/pcie-designware-host.c | 43 +++++++++----------
>>   drivers/pci/controller/dwc/pcie-designware.c  |  8 ++++
>>   drivers/pci/controller/dwc/pcie-designware.h  |  2 +-
>>   3 files changed, 30 insertions(+), 23 deletions(-)
>>
>>
>> base-commit: 568035b01cfb107af8d2e4bd2fb9aea22cf5b868
>
> Thank you in advance.
>
> Regards,
> Evgenii
>
>
>

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