From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lorenzo Pieralisi Subject: Re: [PATCH 3/3] PCI: generic: Add support for Cavium ThunderX PCIe root complexes. Date: Tue, 22 Sep 2015 17:40:12 +0100 Message-ID: <20150922164012.GA3692@red-moon> References: <1442529694-1792-1-git-send-email-ddaney.cavm@gmail.com> <1442529694-1792-4-git-send-email-ddaney.cavm@gmail.com> <20150922160549.GE17444@red-moon> <56017E39.8060606@caviumnetworks.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <56017E39.8060606@caviumnetworks.com> Sender: linux-pci-owner@vger.kernel.org To: David Daney Cc: David Daney , "linux-kernel@vger.kernel.org" , Bjorn Helgaas , "linux-pci@vger.kernel.org" , Will Deacon , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , "linux-arm-kernel@lists.infradead.org" , "devicetree@vger.kernel.org" , Marc Zyngier , David Daney List-Id: devicetree@vger.kernel.org On Tue, Sep 22, 2015 at 05:13:45PM +0100, David Daney wrote: > On 09/22/2015 09:05 AM, Lorenzo Pieralisi wrote: > > On Thu, Sep 17, 2015 at 11:41:34PM +0100, David Daney wrote: [...] > >> Properties of the host controller node: > >> > >> -- compatible : Must be "pci-host-cam-generic" or "pci-host-ecam-generic" > >> - depending on the layout of configuration space (CAM vs > >> - ECAM respectively). > >> +- compatible : One of the following with bus:devfn:reg mapped to the > >> + PCI config space address window in the bit positions shown: > >> + "pci-host-cam-generic" -- 'CAM' bits 16:8:0 > >> + "pci-host-ecam-generic" -- 'ECAM' bits 20:12:0 > >> + "cavium,pci-host-thunder-pem" -- bits 24:16:0 > > > > To me that's ECAM left shifted by 4. Is not it just a matter of defining > > config space base address (ie reg property) differently ? > > No. > > That's like saying ECAM is just CAM shifted by 4, can't we just specify > the "reg" differently. Ok, sorry I was not clear, apologies. I meant to ask if it is something that can be configured in your platform and apparently it is not, I worded it wrongly. > The "reg" property describes the base of the config space access window. > CAM/ECAM/cavium,pci-host-thunder-pem describe how to generate offsets > from that base, The offset calculation requires information that is not > present in the "reg" property, it is enumerated in the various > "compatible" values listed above. Agreed, this also forces you to map in more virtual address space for a given bus, right ? I am also a bit worried about how we can make this work with ACPI, where MCFG accessors take the bus and devfn shifts for granted (ie ECAM specs), so I asked. Thanks, Lorenzo > > David Daney > > > > > Lorenzo > > > >> > >> - device_type : Must be "pci". > >> > >> diff --git a/drivers/pci/host/pci-host-generic.c b/drivers/pci/host/pci-host-generic.c > >> index e364232..e1d8d5b 100644 > >> --- a/drivers/pci/host/pci-host-generic.c > >> +++ b/drivers/pci/host/pci-host-generic.c > >> @@ -91,6 +91,32 @@ static struct gen_pci_cfg_bus_ops gen_pci_cfg_ecam_bus_ops = { > >> } > >> }; > >> > >> +static void __iomem *gen_pci_map_cfg_bus_thunder_pem(struct pci_bus *bus, > >> + unsigned int devfn, > >> + int where) > >> +{ > >> + struct gen_pci *pci = bus->sysdata; > >> + resource_size_t idx = bus->number - pci->cfg.bus_range->start; > >> + > >> + /* > >> + * Thunder PEM is a PCIe RC, but without a root bridge. On > >> + * the primary bus, ignore accesses for devices other than > >> + * the first device. > >> + */ > >> + if (idx == 0 && (devfn & ~7u)) > >> + return NULL; > >> + return pci->cfg.win[idx] + ((devfn << 16) | where); > >> +} > >> + > >> +static struct gen_pci_cfg_bus_ops gen_pci_cfg_thunder_pem_bus_ops = { > >> + .bus_shift = 24, > >> + .ops = { > >> + .map_bus = gen_pci_map_cfg_bus_thunder_pem, > >> + .read = pci_generic_config_read, > >> + .write = pci_generic_config_write, > >> + } > >> +}; > >> + > >> static const struct of_device_id gen_pci_of_match[] = { > >> { .compatible = "pci-host-cam-generic", > >> .data = &gen_pci_cfg_cam_bus_ops }, > >> @@ -98,6 +124,9 @@ static const struct of_device_id gen_pci_of_match[] = { > >> { .compatible = "pci-host-ecam-generic", > >> .data = &gen_pci_cfg_ecam_bus_ops }, > >> > >> + { .compatible = "cavium,pci-host-thunder-pem", > >> + .data = &gen_pci_cfg_thunder_pem_bus_ops }, > >> + > >> { }, > >> }; > >> MODULE_DEVICE_TABLE(of, gen_pci_of_match); > >> -- > >> 1.9.1 > >> > >> -- > >> To unsubscribe from this list: send the line "unsubscribe linux-pci" in > >> the body of a message to majordomo@vger.kernel.org > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > >> >