On Wed, 30 Oct 2024 21:00:43 +0000, Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > On Thu, Oct 24, 2024 at 06:34:44PM -0400, Frank Li wrote: > > Some PCIe host bridges require special handling when enabling or disabling > > PCIe Endpoints. For example, the i.MX95 platform has a lookup table to map > > Requester IDs to StreamIDs, which are used by the SMMU and MSI controller > > to identify the source of DMA accesses. > > > > Without this mapping, DMA accesses may target unintended memory, which > > would corrupt memory or read the wrong data. > > > > Add a host bridge .enable_device() hook the imx6 driver can use to > > configure the Requester ID to StreamID mapping. The hardware table isn't > > big enough to map all possible Requester IDs, so this hook may fail if no > > table space is available. In that case, return failure from > > pci_enable_device(). > > > > It might make more sense to make pci_set_master() decline to enable bus > > mastering and return failure, but it currently doesn't have a way to return > > failure. > > > > Signed-off-by: Frank Li <Frank.Li@xxxxxxx> > > Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > > Merge along with the imx6 change. It'd be good to have this on a stable branch somewhere so that I can refer to it when posting the conversion for the Apple driver to that infrastructure, removing the need for a bus notifier. Otherwise, I'll just cherry-pick that patch and post the whole thing. Thanks, M. -- Without deviation from the norm, progress is not possible.
