| Message ID | 20210805211200.491275-3-jeremy.linton@arm.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | CM4 ACPI PCIe quirk | expand |
On Thu, Aug 05, 2021 at 04:11:59PM -0500, Jeremy Linton wrote: > The PFTF CM4 is an ACPI platform that is following the PCIe SMCCC > standard because its PCIe config space isn't ECAM compliant and is > split into two parts. One part for the root port registers and a > moveable window which points at a given device's 4K config space. > Thus it doesn't have a MCFG (and really any MCFG provided would be > nonsense anyway). As Linux doesn't support the PCIe SMCCC standard > we key off a Linux specific host bridge _DSD to add custom ECAM > ops and cfgres. The cfg op selects between those two regions, as > well as disallowing problematic accesses, particularly if the link > is down because there isn't an attached device. I'm not sure SMCCC is *really* relevant here. If it is, an expansion of the acronym and a link to a spec would be helpful. But AFAICT the only important thing here is that it doesn't have standard ECAM, and we're going to work around that. I don't see anything about _DSD in this series. > Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> > --- > drivers/pci/controller/Makefile | 1 + > drivers/pci/controller/pcie-brcmstb-acpi.c | 77 ++++++++++++++++++++++ > include/linux/pci-ecam.h | 1 + > 3 files changed, 79 insertions(+) > create mode 100644 drivers/pci/controller/pcie-brcmstb-acpi.c > > diff --git a/drivers/pci/controller/Makefile b/drivers/pci/controller/Makefile > index aaf30b3dcc14..65aa6fd3ed89 100644 > --- a/drivers/pci/controller/Makefile > +++ b/drivers/pci/controller/Makefile > @@ -57,5 +57,6 @@ ifdef CONFIG_PCI_QUIRKS > obj-$(CONFIG_ARM64) += pci-thunder-ecam.o > obj-$(CONFIG_ARM64) += pci-thunder-pem.o > obj-$(CONFIG_ARM64) += pci-xgene.o > +obj-$(CONFIG_ARM64) += pcie-brcmstb-acpi.o > endif > endif > diff --git a/drivers/pci/controller/pcie-brcmstb-acpi.c b/drivers/pci/controller/pcie-brcmstb-acpi.c > new file mode 100644 > index 000000000000..76944876155f > --- /dev/null > +++ b/drivers/pci/controller/pcie-brcmstb-acpi.c > @@ -0,0 +1,77 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * ACPI quirks for Brcm2711 PCIe host controller > + * As used on the Raspberry Pi Compute Module 4 > + * > + * Copyright (C) 2021 Arm Ltd. > + */ > + > +#include <linux/io.h> > +#include <linux/pci.h> > +#include <linux/pci-acpi.h> Do we use something from pci-acpi.h? > +#include <linux/pci-ecam.h> > +#include "../pci.h" > +#include "pcie-brcmstb.h" > + > +static int brcm_acpi_init(struct pci_config_window *cfg) > +{ > + /* > + * This platform doesn't technically have anything that could be called > + * ECAM. Its config region has root port specific registers between > + * standard PCIe defined config registers. Thus the region setup by the > + * generic ECAM code needs to be adjusted. The HW can access bus 0-ff > + * but the footprint isn't a nice power of 2 (40k). For purposes of > + * mapping the config region we are just going to squash the standard > + * and nonstandard registers together rather than mapping them > + * separately. This code simply honors the quirk provided base+size > + * instead. > + */ > + iounmap(cfg->win); > + cfg->win = pci_remap_cfgspace(cfg->res.start, resource_size(&cfg->res)); > + if (!cfg->win) > + goto err_exit; > + > + /* MSI is nonstandard as well */ > + pci_no_msi(); > + > + return 0; > +err_exit: > + dev_err(cfg->parent, "PCI: Failed to remap config\n"); > + return -ENOMEM; > +} > + > +static void __iomem *brcm_pcie_map_conf2(struct pci_bus *bus, unsigned int devfn, > + int where) Rewrap to fit in 80 columns. 81 is just ... weird :) > +{ > + struct pci_config_window *cfg = bus->sysdata; > + void __iomem *base = cfg->win; > + int idx; > + u32 up; > + > + /* Accesses to the RC go right to the RC registers if slot==0 */ > + if (pci_is_root_bus(bus)) > + return PCI_SLOT(devfn) ? NULL : base + where; > + > + /* Assure link up before sending request */ > + up = readl(base + PCIE_MISC_PCIE_STATUS); > + if (!(up & PCIE_MISC_PCIE_STATUS_PCIE_DL_ACTIVE_MASK)) > + return NULL; > + > + if (!(up & PCIE_MISC_PCIE_STATUS_PCIE_PHYLINKUP_MASK)) > + return NULL; What happens if the link goes down here? Hopefully that's a recoverable error? > + /* For devices, write to the config space index register */ > + idx = PCIE_ECAM_OFFSET(bus->number, devfn, 0); > + writel(idx, base + PCIE_EXT_CFG_INDEX); > + return base + PCIE_EXT_CFG_DATA + where; > +} > + > +const struct pci_ecam_ops bcm2711_pcie_ops = { > + .init = brcm_acpi_init, > + .bus_shift = 1, > + .pci_ops = { > + .map_bus = brcm_pcie_map_conf2, > + .read = pci_generic_config_read, > + .write = pci_generic_config_write, > + } > +}; > diff --git a/include/linux/pci-ecam.h b/include/linux/pci-ecam.h > index adea5a4771cf..a5de0285bb7f 100644 > --- a/include/linux/pci-ecam.h > +++ b/include/linux/pci-ecam.h > @@ -87,6 +87,7 @@ extern const struct pci_ecam_ops xgene_v1_pcie_ecam_ops; /* APM X-Gene PCIe v1 * > extern const struct pci_ecam_ops xgene_v2_pcie_ecam_ops; /* APM X-Gene PCIe v2.x */ > extern const struct pci_ecam_ops al_pcie_ops; /* Amazon Annapurna Labs PCIe */ > extern const struct pci_ecam_ops tegra194_pcie_ops; /* Tegra194 PCIe */ > +extern const struct pci_ecam_ops bcm2711_pcie_ops; /* Bcm2711 PCIe */ > #endif > > #if IS_ENABLED(CONFIG_PCI_HOST_COMMON) > -- > 2.31.1 >
Hi, On 8/6/21 5:21 PM, Bjorn Helgaas wrote: > On Thu, Aug 05, 2021 at 04:11:59PM -0500, Jeremy Linton wrote: >> The PFTF CM4 is an ACPI platform that is following the PCIe SMCCC >> standard because its PCIe config space isn't ECAM compliant and is >> split into two parts. One part for the root port registers and a >> moveable window which points at a given device's 4K config space. >> Thus it doesn't have a MCFG (and really any MCFG provided would be >> nonsense anyway). As Linux doesn't support the PCIe SMCCC standard >> we key off a Linux specific host bridge _DSD to add custom ECAM >> ops and cfgres. The cfg op selects between those two regions, as >> well as disallowing problematic accesses, particularly if the link >> is down because there isn't an attached device. > > I'm not sure SMCCC is *really* relevant here. If it is, an expansion > of the acronym and a link to a spec would be helpful. > > But AFAICT the only important thing here is that it doesn't have > standard ECAM, and we're going to work around that. I will reword it a bit. > > I don't see anything about _DSD in this series. That is the "linux,pci-quirk" in the next patch. > >> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> >> --- >> drivers/pci/controller/Makefile | 1 + >> drivers/pci/controller/pcie-brcmstb-acpi.c | 77 ++++++++++++++++++++++ >> include/linux/pci-ecam.h | 1 + >> 3 files changed, 79 insertions(+) >> create mode 100644 drivers/pci/controller/pcie-brcmstb-acpi.c >> >> diff --git a/drivers/pci/controller/Makefile b/drivers/pci/controller/Makefile >> index aaf30b3dcc14..65aa6fd3ed89 100644 >> --- a/drivers/pci/controller/Makefile >> +++ b/drivers/pci/controller/Makefile >> @@ -57,5 +57,6 @@ ifdef CONFIG_PCI_QUIRKS >> obj-$(CONFIG_ARM64) += pci-thunder-ecam.o >> obj-$(CONFIG_ARM64) += pci-thunder-pem.o >> obj-$(CONFIG_ARM64) += pci-xgene.o >> +obj-$(CONFIG_ARM64) += pcie-brcmstb-acpi.o >> endif >> endif >> diff --git a/drivers/pci/controller/pcie-brcmstb-acpi.c b/drivers/pci/controller/pcie-brcmstb-acpi.c >> new file mode 100644 >> index 000000000000..76944876155f >> --- /dev/null >> +++ b/drivers/pci/controller/pcie-brcmstb-acpi.c >> @@ -0,0 +1,77 @@ >> +// SPDX-License-Identifier: GPL-2.0+ >> +/* >> + * ACPI quirks for Brcm2711 PCIe host controller >> + * As used on the Raspberry Pi Compute Module 4 >> + * >> + * Copyright (C) 2021 Arm Ltd. >> + */ >> + >> +#include <linux/io.h> >> +#include <linux/pci.h> >> +#include <linux/pci-acpi.h> > > Do we use something from pci-acpi.h? Good catch. > >> +#include <linux/pci-ecam.h> >> +#include "../pci.h" >> +#include "pcie-brcmstb.h" >> + >> +static int brcm_acpi_init(struct pci_config_window *cfg) >> +{ >> + /* >> + * This platform doesn't technically have anything that could be called >> + * ECAM. Its config region has root port specific registers between >> + * standard PCIe defined config registers. Thus the region setup by the >> + * generic ECAM code needs to be adjusted. The HW can access bus 0-ff >> + * but the footprint isn't a nice power of 2 (40k). For purposes of >> + * mapping the config region we are just going to squash the standard >> + * and nonstandard registers together rather than mapping them >> + * separately. This code simply honors the quirk provided base+size >> + * instead. >> + */ >> + iounmap(cfg->win); >> + cfg->win = pci_remap_cfgspace(cfg->res.start, resource_size(&cfg->res)); >> + if (!cfg->win) >> + goto err_exit; >> + >> + /* MSI is nonstandard as well */ >> + pci_no_msi(); >> + >> + return 0; >> +err_exit: >> + dev_err(cfg->parent, "PCI: Failed to remap config\n"); >> + return -ENOMEM; >> +} >> + >> +static void __iomem *brcm_pcie_map_conf2(struct pci_bus *bus, unsigned int devfn, >> + int where) > > Rewrap to fit in 80 columns. 81 is just ... weird :) Sure, > >> +{ >> + struct pci_config_window *cfg = bus->sysdata; >> + void __iomem *base = cfg->win; >> + int idx; >> + u32 up; >> + >> + /* Accesses to the RC go right to the RC registers if slot==0 */ >> + if (pci_is_root_bus(bus)) >> + return PCI_SLOT(devfn) ? NULL : base + where; >> + >> + /* Assure link up before sending request */ >> + up = readl(base + PCIE_MISC_PCIE_STATUS); >> + if (!(up & PCIE_MISC_PCIE_STATUS_PCIE_DL_ACTIVE_MASK)) >> + return NULL; >> + >> + if (!(up & PCIE_MISC_PCIE_STATUS_PCIE_PHYLINKUP_MASK)) >> + return NULL; > > What happens if the link goes down here? Hopefully that's a > recoverable error? This check is intended to verify that something is plugged into the first bus/slot before attempting to probe it. If nothing is plugged in bad things (TM) happen without this check. But, you sparked my curiosity. I've had some reasonable luck with error recovery with a number of those cheap pcie->pcie switches that passively route PCIe over USB3 cables when plugged into this thing. So, I tried hotpluging the first one to see what happens. Game over! :) Linux was nice enough to tell me it couldn't change the power state back to active, but it looks like the link state actually recovered. OTOH, the downstream switch appeared to need reconfiguration even though it was on a separate power domain. Given, I booted the machine off a NVMe drive plugged into that switch, I got another nice screen full of blk_mq errors before it officially passed on. So, the link appears to recover, but that doesn't appear to be enough to make the downstream devices recoverable. Thanks, > >> + /* For devices, write to the config space index register */ >> + idx = PCIE_ECAM_OFFSET(bus->number, devfn, 0); >> + writel(idx, base + PCIE_EXT_CFG_INDEX); >> + return base + PCIE_EXT_CFG_DATA + where; >> +} >> + >> +const struct pci_ecam_ops bcm2711_pcie_ops = { >> + .init = brcm_acpi_init, >> + .bus_shift = 1, >> + .pci_ops = { >> + .map_bus = brcm_pcie_map_conf2, >> + .read = pci_generic_config_read, >> + .write = pci_generic_config_write, >> + } >> +}; >> diff --git a/include/linux/pci-ecam.h b/include/linux/pci-ecam.h >> index adea5a4771cf..a5de0285bb7f 100644 >> --- a/include/linux/pci-ecam.h >> +++ b/include/linux/pci-ecam.h >> @@ -87,6 +87,7 @@ extern const struct pci_ecam_ops xgene_v1_pcie_ecam_ops; /* APM X-Gene PCIe v1 * >> extern const struct pci_ecam_ops xgene_v2_pcie_ecam_ops; /* APM X-Gene PCIe v2.x */ >> extern const struct pci_ecam_ops al_pcie_ops; /* Amazon Annapurna Labs PCIe */ >> extern const struct pci_ecam_ops tegra194_pcie_ops; /* Tegra194 PCIe */ >> +extern const struct pci_ecam_ops bcm2711_pcie_ops; /* Bcm2711 PCIe */ >> #endif >> >> #if IS_ENABLED(CONFIG_PCI_HOST_COMMON) >> -- >> 2.31.1 >>
On Fri, Aug 06, 2021 at 09:55:27PM -0500, Jeremy Linton wrote: > Hi, > > On 8/6/21 5:21 PM, Bjorn Helgaas wrote: > > On Thu, Aug 05, 2021 at 04:11:59PM -0500, Jeremy Linton wrote: > > > The PFTF CM4 is an ACPI platform that is following the PCIe SMCCC > > > standard because its PCIe config space isn't ECAM compliant and is > > > split into two parts. One part for the root port registers and a > > > moveable window which points at a given device's 4K config space. > > > Thus it doesn't have a MCFG (and really any MCFG provided would be > > > nonsense anyway). As Linux doesn't support the PCIe SMCCC standard > > > we key off a Linux specific host bridge _DSD to add custom ECAM > > > ops and cfgres. The cfg op selects between those two regions, as > > > well as disallowing problematic accesses, particularly if the link > > > is down because there isn't an attached device. > > > > I'm not sure SMCCC is *really* relevant here. If it is, an expansion > > of the acronym and a link to a spec would be helpful. > > > > But AFAICT the only important thing here is that it doesn't have > > standard ECAM, and we're going to work around that. > > I will reword it a bit. > > > I don't see anything about _DSD in this series. > > That is the "linux,pci-quirk" in the next patch. The next patch doesn't mention _DSD either. Is it obfuscated by being inside fwnode_property_read_string()? If so, it's well and truly hidden; I gave up trying to connect that with ACPI. Bjorn
Hi, On 8/9/21 12:42 PM, Bjorn Helgaas wrote: > On Fri, Aug 06, 2021 at 09:55:27PM -0500, Jeremy Linton wrote: >> Hi, >> >> On 8/6/21 5:21 PM, Bjorn Helgaas wrote: >>> On Thu, Aug 05, 2021 at 04:11:59PM -0500, Jeremy Linton wrote: >>>> The PFTF CM4 is an ACPI platform that is following the PCIe SMCCC >>>> standard because its PCIe config space isn't ECAM compliant and is >>>> split into two parts. One part for the root port registers and a >>>> moveable window which points at a given device's 4K config space. >>>> Thus it doesn't have a MCFG (and really any MCFG provided would be >>>> nonsense anyway). As Linux doesn't support the PCIe SMCCC standard >>>> we key off a Linux specific host bridge _DSD to add custom ECAM >>>> ops and cfgres. The cfg op selects between those two regions, as >>>> well as disallowing problematic accesses, particularly if the link >>>> is down because there isn't an attached device. >>> >>> I'm not sure SMCCC is *really* relevant here. If it is, an expansion >>> of the acronym and a link to a spec would be helpful. >>> >>> But AFAICT the only important thing here is that it doesn't have >>> standard ECAM, and we're going to work around that. >> >> I will reword it a bit. >> >>> I don't see anything about _DSD in this series. >> >> That is the "linux,pci-quirk" in the next patch. > > The next patch doesn't mention _DSD either. Is it obfuscated by > being inside fwnode_property_read_string()? If so, it's well and > truly hidden; I gave up trying to connect that with ACPI. Right, the fwnode stuff works as a DT/ACPI abstraction for reading values from firmware tables. In this case the ACPI definition looks something like: Device(PCI0) { ... Name (_DSD, Package () { ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package () { Package () { "linux-pcie-quirk", "bcm2711" }, } }) ... } Which explains a bit of why the underlying code is a bit uh... complicated.
On Mon, Aug 09, 2021 at 02:48:17PM -0500, Jeremy Linton wrote: > Hi, > > On 8/9/21 12:42 PM, Bjorn Helgaas wrote: > > On Fri, Aug 06, 2021 at 09:55:27PM -0500, Jeremy Linton wrote: > > > Hi, > > > > > > On 8/6/21 5:21 PM, Bjorn Helgaas wrote: > > > > On Thu, Aug 05, 2021 at 04:11:59PM -0500, Jeremy Linton wrote: > > > > > The PFTF CM4 is an ACPI platform that is following the PCIe SMCCC > > > > > standard because its PCIe config space isn't ECAM compliant and is > > > > > split into two parts. One part for the root port registers and a > > > > > moveable window which points at a given device's 4K config space. > > > > > Thus it doesn't have a MCFG (and really any MCFG provided would be > > > > > nonsense anyway). As Linux doesn't support the PCIe SMCCC standard > > > > > we key off a Linux specific host bridge _DSD to add custom ECAM > > > > > ops and cfgres. The cfg op selects between those two regions, as > > > > > well as disallowing problematic accesses, particularly if the link > > > > > is down because there isn't an attached device. > > > > > > > > I'm not sure SMCCC is *really* relevant here. If it is, an expansion > > > > of the acronym and a link to a spec would be helpful. > > > > > > > > But AFAICT the only important thing here is that it doesn't have > > > > standard ECAM, and we're going to work around that. > > > > > > I will reword it a bit. > > > > > > > I don't see anything about _DSD in this series. > > > > > > That is the "linux,pci-quirk" in the next patch. > > > > The next patch doesn't mention _DSD either. Is it obfuscated by > > being inside fwnode_property_read_string()? If so, it's well and > > truly hidden; I gave up trying to connect that with ACPI. > > Right, the fwnode stuff works as a DT/ACPI abstraction for reading values > from firmware tables. In this case the ACPI definition looks something like: > > Device(PCI0) { > ... > Name (_DSD, Package () { > ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), > Package () { > Package () { "linux-pcie-quirk", "bcm2711" }, > } > }) > > ... > } > > Which explains a bit of why the underlying code is a bit uh... complicated. Wow, that's ... special. I think I would include "ecam" or something in the name. There might be a variety of quirks, e.g., "P2PDMA allowed between root ports", that could reasonably fit under "linux-pcie-quirk".
Hi, On 8/9/21 3:33 PM, Bjorn Helgaas wrote: > On Mon, Aug 09, 2021 at 02:48:17PM -0500, Jeremy Linton wrote: >> Hi, >> >> On 8/9/21 12:42 PM, Bjorn Helgaas wrote: >>> On Fri, Aug 06, 2021 at 09:55:27PM -0500, Jeremy Linton wrote: >>>> Hi, >>>> >>>> On 8/6/21 5:21 PM, Bjorn Helgaas wrote: >>>>> On Thu, Aug 05, 2021 at 04:11:59PM -0500, Jeremy Linton wrote: >>>>>> The PFTF CM4 is an ACPI platform that is following the PCIe SMCCC >>>>>> standard because its PCIe config space isn't ECAM compliant and is >>>>>> split into two parts. One part for the root port registers and a >>>>>> moveable window which points at a given device's 4K config space. >>>>>> Thus it doesn't have a MCFG (and really any MCFG provided would be >>>>>> nonsense anyway). As Linux doesn't support the PCIe SMCCC standard >>>>>> we key off a Linux specific host bridge _DSD to add custom ECAM >>>>>> ops and cfgres. The cfg op selects between those two regions, as >>>>>> well as disallowing problematic accesses, particularly if the link >>>>>> is down because there isn't an attached device. >>>>> >>>>> I'm not sure SMCCC is *really* relevant here. If it is, an expansion >>>>> of the acronym and a link to a spec would be helpful. >>>>> >>>>> But AFAICT the only important thing here is that it doesn't have >>>>> standard ECAM, and we're going to work around that. >>>> >>>> I will reword it a bit. >>>> >>>>> I don't see anything about _DSD in this series. >>>> >>>> That is the "linux,pci-quirk" in the next patch. >>> >>> The next patch doesn't mention _DSD either. Is it obfuscated by >>> being inside fwnode_property_read_string()? If so, it's well and >>> truly hidden; I gave up trying to connect that with ACPI. >> >> Right, the fwnode stuff works as a DT/ACPI abstraction for reading values >> from firmware tables. In this case the ACPI definition looks something like: >> >> Device(PCI0) { >> ... >> Name (_DSD, Package () { >> ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), >> Package () { >> Package () { "linux-pcie-quirk", "bcm2711" }, >> } >> }) >> >> ... >> } >> >> Which explains a bit of why the underlying code is a bit uh... complicated. > > Wow, that's ... special. > > I think I would include "ecam" or something in the name. There might > be a variety of quirks, e.g., "P2PDMA allowed between root ports", > that could reasonably fit under "linux-pcie-quirk". > I think I mentioned "linux-ecam-quirk-id" in the bit with Rob. How is that? I think the description would be something roughly: MCFG oem id override string which selects a platform specific ECAM accessor quirk. Thanks,
diff --git a/drivers/pci/controller/Makefile b/drivers/pci/controller/Makefile index aaf30b3dcc14..65aa6fd3ed89 100644 --- a/drivers/pci/controller/Makefile +++ b/drivers/pci/controller/Makefile @@ -57,5 +57,6 @@ ifdef CONFIG_PCI_QUIRKS obj-$(CONFIG_ARM64) += pci-thunder-ecam.o obj-$(CONFIG_ARM64) += pci-thunder-pem.o obj-$(CONFIG_ARM64) += pci-xgene.o +obj-$(CONFIG_ARM64) += pcie-brcmstb-acpi.o endif endif diff --git a/drivers/pci/controller/pcie-brcmstb-acpi.c b/drivers/pci/controller/pcie-brcmstb-acpi.c new file mode 100644 index 000000000000..76944876155f --- /dev/null +++ b/drivers/pci/controller/pcie-brcmstb-acpi.c @@ -0,0 +1,77 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * ACPI quirks for Brcm2711 PCIe host controller + * As used on the Raspberry Pi Compute Module 4 + * + * Copyright (C) 2021 Arm Ltd. + */ + +#include <linux/io.h> +#include <linux/pci.h> +#include <linux/pci-acpi.h> +#include <linux/pci-ecam.h> +#include "../pci.h" +#include "pcie-brcmstb.h" + +static int brcm_acpi_init(struct pci_config_window *cfg) +{ + /* + * This platform doesn't technically have anything that could be called + * ECAM. Its config region has root port specific registers between + * standard PCIe defined config registers. Thus the region setup by the + * generic ECAM code needs to be adjusted. The HW can access bus 0-ff + * but the footprint isn't a nice power of 2 (40k). For purposes of + * mapping the config region we are just going to squash the standard + * and nonstandard registers together rather than mapping them + * separately. This code simply honors the quirk provided base+size + * instead. + */ + iounmap(cfg->win); + cfg->win = pci_remap_cfgspace(cfg->res.start, resource_size(&cfg->res)); + if (!cfg->win) + goto err_exit; + + /* MSI is nonstandard as well */ + pci_no_msi(); + + return 0; +err_exit: + dev_err(cfg->parent, "PCI: Failed to remap config\n"); + return -ENOMEM; +} + +static void __iomem *brcm_pcie_map_conf2(struct pci_bus *bus, unsigned int devfn, + int where) +{ + struct pci_config_window *cfg = bus->sysdata; + void __iomem *base = cfg->win; + int idx; + u32 up; + + /* Accesses to the RC go right to the RC registers if slot==0 */ + if (pci_is_root_bus(bus)) + return PCI_SLOT(devfn) ? NULL : base + where; + + /* Assure link up before sending request */ + up = readl(base + PCIE_MISC_PCIE_STATUS); + if (!(up & PCIE_MISC_PCIE_STATUS_PCIE_DL_ACTIVE_MASK)) + return NULL; + + if (!(up & PCIE_MISC_PCIE_STATUS_PCIE_PHYLINKUP_MASK)) + return NULL; + + /* For devices, write to the config space index register */ + idx = PCIE_ECAM_OFFSET(bus->number, devfn, 0); + writel(idx, base + PCIE_EXT_CFG_INDEX); + return base + PCIE_EXT_CFG_DATA + where; +} + +const struct pci_ecam_ops bcm2711_pcie_ops = { + .init = brcm_acpi_init, + .bus_shift = 1, + .pci_ops = { + .map_bus = brcm_pcie_map_conf2, + .read = pci_generic_config_read, + .write = pci_generic_config_write, + } +}; diff --git a/include/linux/pci-ecam.h b/include/linux/pci-ecam.h index adea5a4771cf..a5de0285bb7f 100644 --- a/include/linux/pci-ecam.h +++ b/include/linux/pci-ecam.h @@ -87,6 +87,7 @@ extern const struct pci_ecam_ops xgene_v1_pcie_ecam_ops; /* APM X-Gene PCIe v1 * extern const struct pci_ecam_ops xgene_v2_pcie_ecam_ops; /* APM X-Gene PCIe v2.x */ extern const struct pci_ecam_ops al_pcie_ops; /* Amazon Annapurna Labs PCIe */ extern const struct pci_ecam_ops tegra194_pcie_ops; /* Tegra194 PCIe */ +extern const struct pci_ecam_ops bcm2711_pcie_ops; /* Bcm2711 PCIe */ #endif #if IS_ENABLED(CONFIG_PCI_HOST_COMMON)
The PFTF CM4 is an ACPI platform that is following the PCIe SMCCC standard because its PCIe config space isn't ECAM compliant and is split into two parts. One part for the root port registers and a moveable window which points at a given device's 4K config space. Thus it doesn't have a MCFG (and really any MCFG provided would be nonsense anyway). As Linux doesn't support the PCIe SMCCC standard we key off a Linux specific host bridge _DSD to add custom ECAM ops and cfgres. The cfg op selects between those two regions, as well as disallowing problematic accesses, particularly if the link is down because there isn't an attached device. Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> --- drivers/pci/controller/Makefile | 1 + drivers/pci/controller/pcie-brcmstb-acpi.c | 77 ++++++++++++++++++++++ include/linux/pci-ecam.h | 1 + 3 files changed, 79 insertions(+) create mode 100644 drivers/pci/controller/pcie-brcmstb-acpi.c -- 2.31.1