On Tue, 14 Sep 2021 10:56:05 +0100, Mark Kettenis <mark.kettenis@xxxxxxxxx> wrote: > > > Date: Tue, 14 Sep 2021 10:35:32 +0100 > > From: Marc Zyngier <maz@xxxxxxxxxx> > > > > On Mon, 13 Sep 2021 21:45:13 +0100, > > "Sven Peter" <sven@xxxxxxxxxxxxx> wrote: > > > > > > On Mon, Sep 13, 2021, at 20:25, Marc Zyngier wrote: > > > > The Apple PCIe controller doesn't directly feed the endpoint's > > > > Requester ID to the IOMMU (DART), but instead maps RIDs onto > > > > Stream IDs (SIDs). The DART and the PCIe controller must thus > > > > agree on the SIDs that are used for translation (by using > > > > the 'iommu-map' property). > > > > > > > > For this purpose, parse the 'iommu-map' property each time a > > > > device gets added, and use the resulting translation to configure > > > > the PCIe RID-to-SID mapper. Similarily, remove the translation > > > > if/when the device gets removed. > > > > > > > > This is all driven from a bus notifier which gets registered at > > > > probe time. Hopefully this is the only PCI controller driver > > > > in the whole system. > > > > > > > > Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx> > > > > --- > > > > drivers/pci/controller/pcie-apple.c | 158 +++++++++++++++++++++++++++- > > > > 1 file changed, 156 insertions(+), 2 deletions(-) > > > > > > > > diff --git a/drivers/pci/controller/pcie-apple.c > > > > b/drivers/pci/controller/pcie-apple.c > > > > index 76344223245d..68d71eabe708 100644 > > > > --- a/drivers/pci/controller/pcie-apple.c > > > > +++ b/drivers/pci/controller/pcie-apple.c > > > > @@ -23,8 +23,10 @@ > > > > #include <linux/iopoll.h> > > > > #include <linux/irqchip/chained_irq.h> > > > > #include <linux/irqdomain.h> > > > > +#include <linux/list.h> > > > > #include <linux/module.h> > > > > #include <linux/msi.h> > > > > +#include <linux/notifier.h> > > > > #include <linux/of_irq.h> > > > > #include <linux/pci-ecam.h> > > > > > > > > @@ -116,6 +118,8 @@ > > > > #define PORT_TUNSTAT_PERST_ACK_PEND BIT(1) > > > > #define PORT_PREFMEM_ENABLE 0x00994 > > > > > > > > +#define MAX_RID2SID 64 > > > > > > Do these actually have 64 slots? I thought that was only for > > > the Thunderbolt controllers and that these only had 16. > > > > You are indeed right, and I blindly used the limit used in the > > Correlium driver. Using entries from 16 onward result in a non booting > > system. The registers do not fault though, and simply ignore writes. I > > came up with an simple fix for this, see below. > > Or should be add a property to the DT binding to indicate the number > of entries (using a default of 16)? We don't have to add that > property right away; we can delay that until we actually try to > support the Thunderbolt ports. I'd rather only add a property for things we cannot discover ourselves. And indeed, we don't have to decide on this right now. > In case you didn't know already, RIDs that have no mapping in the > RID2SID table map to SID 0. That's why I picked 1 as the SID in the > iommu-map property for the port. I sort-off guessed, as using 0 made everything work by 'magic', while using your DT prevented the machine from booting. I tend to dislike magic, hence this patch. > > > > I never checked it myself though and it doesn't make much > > > of a difference for now since only four different RIDs will > > > ever be connected anyway. > > > > Four? I guess the radios expose more than a single RID? > > At this point, on the M1 mini there is the Broadcom BCM4378 WiFi/BT > device (which has two functions), the Fresco Logic FL1100 xHCI > controller (single function) and the Broadcom BCM57765 Ethernet > controller. So yes, there are for RIDs. But as far as I can see, the RID-to-SID mapping is per port. So at most, we have two RIDs per port/DART, not four. Or am I missing something altogether? M. -- Without deviation from the norm, progress is not possible.
