* [PATCH v3 0/1] arm64: PCI SMC config conduit
@ 2021-01-21 4:17 ` Jeremy Linton
0 siblings, 0 replies; 4+ messages in thread
From: Jeremy Linton @ 2021-01-21 4:17 UTC (permalink / raw)
To: linux-arm-kernel
Cc: catalin.marinas, will, mark.rutland, lorenzo.pieralisi,
sudeep.holla, bhelgaas, robh, vidyas, linux-kernel,
Jeremy Linton
This set provides a platform standardized way to access PCI
config space. It does that via an Arm specific interface
exported by the firmware. The Arm specification this is
based on can be found here:
The Arm PCI Configuration Space Access Firmware Interface
https://developer.arm.com/documentation/den0115/latest
v2->v3:
Convert from SMC only calls to arm_smccc_1_1_invoke() for better
conformance with the specification.
v1->v2:
Add SMC_PCI_FEATURES calls to verify _READ, _WRITE and _SEG_INFO
functions exist.
Add a _SEG_INFO bus start, end validation against the ACPI table.
Adjust some function naming, and log messages.
Jeremy Linton (1):
arm64: PCI: Enable SMC conduit
arch/arm64/kernel/pci.c | 111 ++++++++++++++++++++++++++++++++++++++
include/linux/arm-smccc.h | 29 ++++++++++
2 files changed, 140 insertions(+)
--
2.26.2
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH v3 0/1] arm64: PCI SMC config conduit @ 2021-01-21 4:17 ` Jeremy Linton 0 siblings, 0 replies; 4+ messages in thread From: Jeremy Linton @ 2021-01-21 4:17 UTC (permalink / raw) To: linux-arm-kernel Cc: mark.rutland, lorenzo.pieralisi, catalin.marinas, linux-kernel, Jeremy Linton, vidyas, sudeep.holla, bhelgaas, will This set provides a platform standardized way to access PCI config space. It does that via an Arm specific interface exported by the firmware. The Arm specification this is based on can be found here: The Arm PCI Configuration Space Access Firmware Interface https://developer.arm.com/documentation/den0115/latest v2->v3: Convert from SMC only calls to arm_smccc_1_1_invoke() for better conformance with the specification. v1->v2: Add SMC_PCI_FEATURES calls to verify _READ, _WRITE and _SEG_INFO functions exist. Add a _SEG_INFO bus start, end validation against the ACPI table. Adjust some function naming, and log messages. Jeremy Linton (1): arm64: PCI: Enable SMC conduit arch/arm64/kernel/pci.c | 111 ++++++++++++++++++++++++++++++++++++++ include/linux/arm-smccc.h | 29 ++++++++++ 2 files changed, 140 insertions(+) -- 2.26.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v3 1/1] arm64: PCI: Enable SMC conduit 2021-01-21 4:17 ` Jeremy Linton @ 2021-01-21 4:17 ` Jeremy Linton -1 siblings, 0 replies; 4+ messages in thread From: Jeremy Linton @ 2021-01-21 4:17 UTC (permalink / raw) To: linux-arm-kernel Cc: catalin.marinas, will, mark.rutland, lorenzo.pieralisi, sudeep.holla, bhelgaas, robh, vidyas, linux-kernel, Jeremy Linton Given that most arm64 platforms' PCI implementations need quirks to deal with problematic config accesses, this is a good place to apply a firmware abstraction. The ARM PCI Configuration Space Access Firmware Interface specification details a standard SMC conduit designed to provide a simple PCI config accessor. This specification enhances the existing ACPI/PCI abstraction and expects power, config, etc., is handled by the platform. It also is very explicit that the resulting config space registers must behave as is specified by the PCI specification. Hook the ACPI/PCI config path, and when missing MCFG data is detected, attempt to probe the SMC conduit. If the conduit exists and responds to the requested segment, provided by the ACPI namespace, attach a custom pci_ecam_ops which redirects all config read/write requests to the firmware. The Arm PCI Configuration Space Access Firmware Interface: https://developer.arm.com/documentation/den0115/latest Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> --- arch/arm64/kernel/pci.c | 111 ++++++++++++++++++++++++++++++++++++++ include/linux/arm-smccc.h | 29 ++++++++++ 2 files changed, 140 insertions(+) diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c index 1006ed2d7c60..80c60cc0137a 100644 --- a/arch/arm64/kernel/pci.c +++ b/arch/arm64/kernel/pci.c @@ -7,6 +7,7 @@ */ #include <linux/acpi.h> +#include <linux/arm-smccc.h> #include <linux/init.h> #include <linux/io.h> #include <linux/kernel.h> @@ -107,6 +108,114 @@ static int pci_acpi_root_prepare_resources(struct acpi_pci_root_info *ci) return status; } +static int smccc_pcie_has_conduit(void) +{ + struct arm_smccc_res res; + + if (arm_smccc_1_1_get_conduit() == SMCCC_CONDUIT_NONE) + return -EOPNOTSUPP; + + arm_smccc_1_1_invoke(SMCCC_PCI_VERSION, 0, 0, 0, 0, 0, 0, 0, &res); + if ((int)res.a0 < 0) + return -EOPNOTSUPP; + + arm_smccc_1_1_invoke(SMCCC_PCI_FEATURES, + SMCCC_PCI_WRITE, 0, 0, 0, 0, 0, 0, &res); + if ((int)res.a0 < 0) + return -EOPNOTSUPP; + + arm_smccc_1_1_invoke(SMCCC_PCI_FEATURES, + SMCCC_PCI_READ, 0, 0, 0, 0, 0, 0, &res); + if ((int)res.a0 < 0) + return -EOPNOTSUPP; + + arm_smccc_1_1_invoke(SMCCC_PCI_FEATURES, + SMCCC_PCI_SEG_INFO, 0, 0, 0, 0, 0, 0, &res); + if ((int)res.a0 < 0) + return -EOPNOTSUPP; + + return 0; +} + +static int smccc_pcie_config_read(struct pci_bus *bus, unsigned int devfn, + int where, int size, u32 *val) +{ + struct arm_smccc_res res; + + devfn |= bus->number << 8; + devfn |= bus->domain_nr << 16; + + arm_smccc_1_1_invoke(SMCCC_PCI_READ, devfn, where, size, + 0, 0, 0, 0, &res); + if (res.a0) { + *val = ~0; + return -PCIBIOS_BAD_REGISTER_NUMBER; + } + + *val = res.a1; + return PCIBIOS_SUCCESSFUL; +} + +static int smccc_pcie_config_write(struct pci_bus *bus, unsigned int devfn, + int where, int size, u32 val) +{ + struct arm_smccc_res res; + + devfn |= bus->number << 8; + devfn |= bus->domain_nr << 16; + + arm_smccc_1_1_invoke(SMCCC_PCI_WRITE, devfn, where, size, val, + 0, 0, 0, &res); + if (res.a0) + return -PCIBIOS_BAD_REGISTER_NUMBER; + + return PCIBIOS_SUCCESSFUL; +} + +static const struct pci_ecam_ops smccc_pcie_ops = { + .pci_ops = { + .read = smccc_pcie_config_read, + .write = smccc_pcie_config_write, + } +}; + +static struct pci_config_window * +pci_acpi_setup_smccc_mapping(struct acpi_pci_root *root) +{ + struct device *dev = &root->device->dev; + struct arm_smccc_res res; + struct resource *bus_res = &root->secondary; + struct pci_config_window *cfg; + u16 seg = root->segment; + + arm_smccc_1_1_invoke(SMCCC_PCI_SEG_INFO, seg, 0, 0, 0, 0, 0, 0, &res); + if ((int)res.a0 < 0) { + pr_warn("PCI: SMC segment %d doesn't exist\n", seg); + return NULL; + } + + if (FIELD_GET(SMCCC_PCI_SEG_INFO_START_BUS, res.a1) != bus_res->start || + FIELD_GET(SMCCC_PCI_SEG_INFO_END_BUS, res.a1) != bus_res->end) { + pr_warn("PCI: SMC segment %d doesn't match ACPI description\n", seg); + return NULL; + } + + cfg = kzalloc(sizeof(*cfg), GFP_KERNEL); + if (!cfg) + return NULL; + + cfg->parent = dev; + cfg->ops = &smccc_pcie_ops; + cfg->busr.start = bus_res->start; + cfg->busr.end = bus_res->end; + cfg->busr.flags = IORESOURCE_BUS; + cfg->res.name = "PCI SMCCC"; + + pr_info("PCI: SMC conduit attached to segment %d\n", seg); + + return cfg; +} + /* * Lookup the bus range for the domain in MCFG, and set up config space * mapping. @@ -125,6 +234,8 @@ pci_acpi_setup_ecam_mapping(struct acpi_pci_root *root) ret = pci_mcfg_lookup(root, &cfgres, &ecam_ops); if (ret) { + if (!smccc_pcie_has_conduit()) + return pci_acpi_setup_smccc_mapping(root); dev_err(dev, "%04x:%pR ECAM region not found\n", seg, bus_res); return NULL; } diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h index f860645f6512..a1a8fe0ea5aa 100644 --- a/include/linux/arm-smccc.h +++ b/include/linux/arm-smccc.h @@ -89,6 +89,35 @@ #define SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED 1 +/* PCI ECAM conduit (defined by ARM DEN0115A) */ +#define SMCCC_PCI_VERSION \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_STANDARD, 0x0130) + +#define SMCCC_PCI_FEATURES \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_STANDARD, 0x0131) + +#define SMCCC_PCI_READ \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_STANDARD, 0x0132) + +#define SMCCC_PCI_WRITE \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_STANDARD, 0x0133) + +#define SMCCC_PCI_SEG_INFO \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_STANDARD, 0x0134) + +#define SMCCC_PCI_SEG_INFO_START_BUS GENMASK(7, 0) +#define SMCCC_PCI_SEG_INFO_END_BUS GENMASK(15, 8) + /* Paravirtualised time calls (defined by ARM DEN0057A) */ #define ARM_SMCCC_HV_PV_TIME_FEATURES \ ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ -- 2.26.2 ^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v3 1/1] arm64: PCI: Enable SMC conduit @ 2021-01-21 4:17 ` Jeremy Linton 0 siblings, 0 replies; 4+ messages in thread From: Jeremy Linton @ 2021-01-21 4:17 UTC (permalink / raw) To: linux-arm-kernel Cc: mark.rutland, lorenzo.pieralisi, catalin.marinas, linux-kernel, Jeremy Linton, vidyas, sudeep.holla, bhelgaas, will Given that most arm64 platforms' PCI implementations need quirks to deal with problematic config accesses, this is a good place to apply a firmware abstraction. The ARM PCI Configuration Space Access Firmware Interface specification details a standard SMC conduit designed to provide a simple PCI config accessor. This specification enhances the existing ACPI/PCI abstraction and expects power, config, etc., is handled by the platform. It also is very explicit that the resulting config space registers must behave as is specified by the PCI specification. Hook the ACPI/PCI config path, and when missing MCFG data is detected, attempt to probe the SMC conduit. If the conduit exists and responds to the requested segment, provided by the ACPI namespace, attach a custom pci_ecam_ops which redirects all config read/write requests to the firmware. The Arm PCI Configuration Space Access Firmware Interface: https://developer.arm.com/documentation/den0115/latest Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> --- arch/arm64/kernel/pci.c | 111 ++++++++++++++++++++++++++++++++++++++ include/linux/arm-smccc.h | 29 ++++++++++ 2 files changed, 140 insertions(+) diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c index 1006ed2d7c60..80c60cc0137a 100644 --- a/arch/arm64/kernel/pci.c +++ b/arch/arm64/kernel/pci.c @@ -7,6 +7,7 @@ */ #include <linux/acpi.h> +#include <linux/arm-smccc.h> #include <linux/init.h> #include <linux/io.h> #include <linux/kernel.h> @@ -107,6 +108,114 @@ static int pci_acpi_root_prepare_resources(struct acpi_pci_root_info *ci) return status; } +static int smccc_pcie_has_conduit(void) +{ + struct arm_smccc_res res; + + if (arm_smccc_1_1_get_conduit() == SMCCC_CONDUIT_NONE) + return -EOPNOTSUPP; + + arm_smccc_1_1_invoke(SMCCC_PCI_VERSION, 0, 0, 0, 0, 0, 0, 0, &res); + if ((int)res.a0 < 0) + return -EOPNOTSUPP; + + arm_smccc_1_1_invoke(SMCCC_PCI_FEATURES, + SMCCC_PCI_WRITE, 0, 0, 0, 0, 0, 0, &res); + if ((int)res.a0 < 0) + return -EOPNOTSUPP; + + arm_smccc_1_1_invoke(SMCCC_PCI_FEATURES, + SMCCC_PCI_READ, 0, 0, 0, 0, 0, 0, &res); + if ((int)res.a0 < 0) + return -EOPNOTSUPP; + + arm_smccc_1_1_invoke(SMCCC_PCI_FEATURES, + SMCCC_PCI_SEG_INFO, 0, 0, 0, 0, 0, 0, &res); + if ((int)res.a0 < 0) + return -EOPNOTSUPP; + + return 0; +} + +static int smccc_pcie_config_read(struct pci_bus *bus, unsigned int devfn, + int where, int size, u32 *val) +{ + struct arm_smccc_res res; + + devfn |= bus->number << 8; + devfn |= bus->domain_nr << 16; + + arm_smccc_1_1_invoke(SMCCC_PCI_READ, devfn, where, size, + 0, 0, 0, 0, &res); + if (res.a0) { + *val = ~0; + return -PCIBIOS_BAD_REGISTER_NUMBER; + } + + *val = res.a1; + return PCIBIOS_SUCCESSFUL; +} + +static int smccc_pcie_config_write(struct pci_bus *bus, unsigned int devfn, + int where, int size, u32 val) +{ + struct arm_smccc_res res; + + devfn |= bus->number << 8; + devfn |= bus->domain_nr << 16; + + arm_smccc_1_1_invoke(SMCCC_PCI_WRITE, devfn, where, size, val, + 0, 0, 0, &res); + if (res.a0) + return -PCIBIOS_BAD_REGISTER_NUMBER; + + return PCIBIOS_SUCCESSFUL; +} + +static const struct pci_ecam_ops smccc_pcie_ops = { + .pci_ops = { + .read = smccc_pcie_config_read, + .write = smccc_pcie_config_write, + } +}; + +static struct pci_config_window * +pci_acpi_setup_smccc_mapping(struct acpi_pci_root *root) +{ + struct device *dev = &root->device->dev; + struct arm_smccc_res res; + struct resource *bus_res = &root->secondary; + struct pci_config_window *cfg; + u16 seg = root->segment; + + arm_smccc_1_1_invoke(SMCCC_PCI_SEG_INFO, seg, 0, 0, 0, 0, 0, 0, &res); + if ((int)res.a0 < 0) { + pr_warn("PCI: SMC segment %d doesn't exist\n", seg); + return NULL; + } + + if (FIELD_GET(SMCCC_PCI_SEG_INFO_START_BUS, res.a1) != bus_res->start || + FIELD_GET(SMCCC_PCI_SEG_INFO_END_BUS, res.a1) != bus_res->end) { + pr_warn("PCI: SMC segment %d doesn't match ACPI description\n", seg); + return NULL; + } + + cfg = kzalloc(sizeof(*cfg), GFP_KERNEL); + if (!cfg) + return NULL; + + cfg->parent = dev; + cfg->ops = &smccc_pcie_ops; + cfg->busr.start = bus_res->start; + cfg->busr.end = bus_res->end; + cfg->busr.flags = IORESOURCE_BUS; + cfg->res.name = "PCI SMCCC"; + + pr_info("PCI: SMC conduit attached to segment %d\n", seg); + + return cfg; +} + /* * Lookup the bus range for the domain in MCFG, and set up config space * mapping. @@ -125,6 +234,8 @@ pci_acpi_setup_ecam_mapping(struct acpi_pci_root *root) ret = pci_mcfg_lookup(root, &cfgres, &ecam_ops); if (ret) { + if (!smccc_pcie_has_conduit()) + return pci_acpi_setup_smccc_mapping(root); dev_err(dev, "%04x:%pR ECAM region not found\n", seg, bus_res); return NULL; } diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h index f860645f6512..a1a8fe0ea5aa 100644 --- a/include/linux/arm-smccc.h +++ b/include/linux/arm-smccc.h @@ -89,6 +89,35 @@ #define SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED 1 +/* PCI ECAM conduit (defined by ARM DEN0115A) */ +#define SMCCC_PCI_VERSION \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_STANDARD, 0x0130) + +#define SMCCC_PCI_FEATURES \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_STANDARD, 0x0131) + +#define SMCCC_PCI_READ \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_STANDARD, 0x0132) + +#define SMCCC_PCI_WRITE \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_STANDARD, 0x0133) + +#define SMCCC_PCI_SEG_INFO \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_STANDARD, 0x0134) + +#define SMCCC_PCI_SEG_INFO_START_BUS GENMASK(7, 0) +#define SMCCC_PCI_SEG_INFO_END_BUS GENMASK(15, 8) + /* Paravirtualised time calls (defined by ARM DEN0057A) */ #define ARM_SMCCC_HV_PV_TIME_FEATURES \ ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ -- 2.26.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-01-21 4:24 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-01-21 4:17 [PATCH v3 0/1] arm64: PCI SMC config conduit Jeremy Linton 2021-01-21 4:17 ` Jeremy Linton 2021-01-21 4:17 ` [PATCH v3 1/1] arm64: PCI: Enable SMC conduit Jeremy Linton 2021-01-21 4:17 ` Jeremy Linton
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