| Message ID | 20210111225121.820014-3-ben.widawsky@intel.com |
|---|---|
| State | New |
| Headers | show |
| Series | [RFC,v3,01/16] docs: cxl: Add basic documentation | expand |
On 1/11/21 2:51 PM, Ben Widawsky wrote: > diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig > new file mode 100644 > index 000000000000..68da926ba5b1 > --- /dev/null > +++ b/drivers/cxl/Kconfig > @@ -0,0 +1,36 @@ > +# SPDX-License-Identifier: GPL-2.0-only > +menuconfig CXL_BUS > + tristate "CXL (Compute Express Link) Devices Support" > + help > + CXL is a bus that is electrically compatible with PCI-E, but layers > + three protocols on that signalling (CXL.io, CXL.cache, and CXL.mem). > + The CXL.cache protocol allows devices to hold cachelines locally, the > + CXL.mem protocol allows devices to be fully coherent memory targets, > + the CXL.io protocol is equivalent to PCI-E. Say 'y' to enable support > + for the configuration and management of devices supporting these > + protocols. > + > +if CXL_BUS > + > +config CXL_BUS_PROVIDER > + tristate > + > +config CXL_ACPI > + tristate "CXL ACPI: Platform Support" > + depends on ACPI > + default CXL_BUS > + select CXL_BUS_PROVIDER > + help > + Say 'y/m' to enable a driver (named "cxl_acpi.ko" when built > + as a module) that will enable support for CXL.mem endpoint > + devices. In general, CXL Platform Support is a prerequisite > + for any CXL device driver that wants to claim ownership of a > + component register space. By default platform firmware assumes > + Linux is unaware of CXL capabilities and requires explicit > + opt-in. This platform component also mediates resources > + described by the CEDT (CXL Early Discovery Table). See > + Chapter 9.14.1 CXL Early Discovery Table (CEDT) in the CXL 2.0 > + specification. > + > + If unsure say 'm' End above sentence with a '.', please. > +endif
On Mon, 11 Jan 2021 14:51:06 -0800 Ben Widawsky <ben.widawsky@intel.com> wrote: > From: Vishal Verma <vishal.l.verma@intel.com> > > Add an acpi_cxl module to coordinate the ACPI portions of the CXL > (Compute eXpress Link) interconnect. This driver binds to ACPI0017 > objects in the ACPI tree, and coordinates access to the resources > provided by the ACPI CEDT (CXL Early Discovery Table). > > It also coordinates operations of the root port _OSC object to notify > platform firmware that the OS has native support for the CXL > capabilities of endpoints. > > Note: the actbl1.h changes are speculative. The expectation is that they > will arrive through the ACPICA tree in due time. I would pull the ACPICA changes out into a precursor patch. > > Cc: Ben Widawsky <ben.widawsky@intel.com> > Cc: Dan Williams <dan.j.williams@intel.com> > Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Hi, I think it would be good to also add CEDT to the list in drivers/acpi/tables.c so that we can dump it from /sys/firmware/acpi/tables/ and potentially override it from an initrd. https://elixir.bootlin.com/linux/v5.11-rc3/source/drivers/acpi/tables.c#L482 Can be very helpful whilst debugging. Related to that, anyone know if anyone has acpica patches so we can have iasl -d work on the table? Would probably be useful but I'd rather not duplicate work if it's already done. A few minor things inline Jonathan > --- > drivers/Kconfig | 1 + > drivers/Makefile | 1 + > drivers/cxl/Kconfig | 36 ++++++++++++++++ > drivers/cxl/Makefile | 5 +++ > drivers/cxl/acpi.c | 97 +++++++++++++++++++++++++++++++++++++++++++ > drivers/cxl/acpi.h | 15 +++++++ > include/acpi/actbl1.h | 50 ++++++++++++++++++++++ > 7 files changed, 205 insertions(+) > create mode 100644 drivers/cxl/Kconfig > create mode 100644 drivers/cxl/Makefile > create mode 100644 drivers/cxl/acpi.c > create mode 100644 drivers/cxl/acpi.h > > diff --git a/drivers/Kconfig b/drivers/Kconfig > index dcecc9f6e33f..62c753a73651 100644 > --- a/drivers/Kconfig > +++ b/drivers/Kconfig > @@ -6,6 +6,7 @@ menu "Device Drivers" > source "drivers/amba/Kconfig" > source "drivers/eisa/Kconfig" > source "drivers/pci/Kconfig" > +source "drivers/cxl/Kconfig" > source "drivers/pcmcia/Kconfig" > source "drivers/rapidio/Kconfig" > > diff --git a/drivers/Makefile b/drivers/Makefile > index fd11b9ac4cc3..678ea810410f 100644 > --- a/drivers/Makefile > +++ b/drivers/Makefile > @@ -73,6 +73,7 @@ obj-$(CONFIG_NVM) += lightnvm/ > obj-y += base/ block/ misc/ mfd/ nfc/ > obj-$(CONFIG_LIBNVDIMM) += nvdimm/ > obj-$(CONFIG_DAX) += dax/ > +obj-$(CONFIG_CXL_BUS) += cxl/ > obj-$(CONFIG_DMA_SHARED_BUFFER) += dma-buf/ > obj-$(CONFIG_NUBUS) += nubus/ > obj-y += macintosh/ > diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig > new file mode 100644 > index 000000000000..68da926ba5b1 > --- /dev/null > +++ b/drivers/cxl/Kconfig > @@ -0,0 +1,36 @@ > +# SPDX-License-Identifier: GPL-2.0-only > +menuconfig CXL_BUS > + tristate "CXL (Compute Express Link) Devices Support" > + help > + CXL is a bus that is electrically compatible with PCI-E, but layers For consistency with Kconfig in driver/pci probably better to spell PCI Express throughout. > + three protocols on that signalling (CXL.io, CXL.cache, and CXL.mem). > + The CXL.cache protocol allows devices to hold cachelines locally, the > + CXL.mem protocol allows devices to be fully coherent memory targets, > + the CXL.io protocol is equivalent to PCI-E. Say 'y' to enable support > + for the configuration and management of devices supporting these > + protocols. > + > +if CXL_BUS > + > +config CXL_BUS_PROVIDER > + tristate > + > +config CXL_ACPI > + tristate "CXL ACPI: Platform Support" > + depends on ACPI > + default CXL_BUS > + select CXL_BUS_PROVIDER > + help > + Say 'y/m' to enable a driver (named "cxl_acpi.ko" when built > + as a module) that will enable support for CXL.mem endpoint > + devices. In general, CXL Platform Support is a prerequisite > + for any CXL device driver that wants to claim ownership of a > + component register space. By default platform firmware assumes > + Linux is unaware of CXL capabilities and requires explicit > + opt-in. This platform component also mediates resources > + described by the CEDT (CXL Early Discovery Table). See > + Chapter 9.14.1 CXL Early Discovery Table (CEDT) in the CXL 2.0 > + specification. > + > + If unsure say 'm' > +endif > diff --git a/drivers/cxl/Makefile b/drivers/cxl/Makefile > new file mode 100644 > index 000000000000..d38cd34a2582 > --- /dev/null > +++ b/drivers/cxl/Makefile > @@ -0,0 +1,5 @@ > +# SPDX-License-Identifier: GPL-2.0 > +obj-$(CONFIG_CXL_ACPI) += cxl_acpi.o > + > +ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=CXL > +cxl_acpi-y := acpi.o > diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c > new file mode 100644 > index 000000000000..0f1ba9b3f1ed > --- /dev/null > +++ b/drivers/cxl/acpi.c > @@ -0,0 +1,97 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* Copyright(c) 2020 Intel Corporation. All rights reserved. */ > +#include <linux/platform_device.h> > +#include <linux/list_sort.h> > +#include <linux/module.h> > +#include <linux/mutex.h> > +#include <linux/sysfs.h> > +#include <linux/list.h> > +#include <linux/acpi.h> > +#include <linux/sort.h> > +#include <linux/pci.h> Trivial: For includes I'm fairly sure general convention (as much as there is one is to do alphabetical order, not reverse xmas tree). > +#include "acpi.h" > + > +/* > + * If/when CXL support is defined by other platform firmware the kernel > + * will need a mechanism to select between the platform specific version > + * of this routine, until then, hard-code ACPI assumptions > + */ > +int cxl_bus_acquire(struct pci_dev *pdev) > +{ > + struct acpi_device *adev; > + struct pci_dev *root_port; > + struct device *root; > + > + root_port = pcie_find_root_port(pdev); > + if (!root_port) > + return -ENXIO; > + > + root = root_port->dev.parent; > + if (!root) > + return -ENXIO; > + > + adev = ACPI_COMPANION(root); > + if (!adev) > + return -ENXIO; > + > + /* TODO: OSC enabling */ > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(cxl_bus_acquire); > + > +static void acpi_cedt_put_table(void *table) > +{ > + acpi_put_table(table); > +} > + > +static int cxl_acpi_probe(struct platform_device *pdev) > +{ > + struct acpi_device *adev = ACPI_COMPANION(&pdev->dev); > + struct cxl_acpi_desc *acpi_desc; > + struct device *dev = &adev->dev; > + struct acpi_table_header *tbl; > + acpi_status status; > + acpi_size sz; > + int rc; > + > + status = acpi_get_table(ACPI_SIG_CEDT, 0, &tbl); > + if (ACPI_FAILURE(status)) { > + dev_err(dev, "failed to find CEDT at startup\n"); > + return 0; > + } > + > + rc = devm_add_action_or_reset(dev, acpi_cedt_put_table, tbl); > + if (rc) > + return rc; > + > + sz = tbl->length; > + dev_info(dev, "found CEDT at startup: %lld bytes\n", sz); Is this useful? At least for my normal acpi boot I'll see CEDT in the list of detected ACPI tables early in boot. This provides less info than that print already has. > + > + acpi_desc = devm_kzalloc(dev, sizeof(*acpi_desc), GFP_KERNEL); > + if (!acpi_desc) > + return -ENOMEM; > + > + dev_set_drvdata(&adev->dev, acpi_desc); > + acpi_desc->dev = &adev->dev; > + acpi_desc->acpi_header = *tbl; > + > + return 0; > +} > + > +static const struct acpi_device_id cxl_acpi_ids[] = { > + { "ACPI0017", 0 }, > + { "", 0 }, > +}; > +MODULE_DEVICE_TABLE(acpi, cxl_acpi_ids); > + > +static struct platform_driver cxl_acpi_driver = { > + .probe = cxl_acpi_probe, > + .driver = { > + .name = KBUILD_MODNAME, > + .acpi_match_table = cxl_acpi_ids, > + }, > +}; > + > +module_platform_driver(cxl_acpi_driver); > +MODULE_LICENSE("GPL v2"); > diff --git a/drivers/cxl/acpi.h b/drivers/cxl/acpi.h > new file mode 100644 > index 000000000000..d638f8886ab7 > --- /dev/null > +++ b/drivers/cxl/acpi.h > @@ -0,0 +1,15 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* Copyright(c) 2020 Intel Corporation. All rights reserved. */ > + > +#ifndef __CXL_ACPI_H__ > +#define __CXL_ACPI_H__ > +#include <linux/acpi.h> > + > +struct cxl_acpi_desc { > + struct acpi_table_header acpi_header; > + struct device *dev; > +}; > + > +int cxl_bus_acquire(struct pci_dev *pci_dev); > + > +#endif /* __CXL_ACPI_H__ */ > diff --git a/include/acpi/actbl1.h b/include/acpi/actbl1.h > index 43549547ed3e..f3a0303984c8 100644 > --- a/include/acpi/actbl1.h > +++ b/include/acpi/actbl1.h > @@ -28,6 +28,7 @@ > #define ACPI_SIG_BERT "BERT" /* Boot Error Record Table */ > #define ACPI_SIG_BGRT "BGRT" /* Boot Graphics Resource Table */ > #define ACPI_SIG_BOOT "BOOT" /* Simple Boot Flag Table */ > +#define ACPI_SIG_CEDT "CEDT" /* CXL Early Discovery Table */ > #define ACPI_SIG_CPEP "CPEP" /* Corrected Platform Error Polling table */ > #define ACPI_SIG_CSRT "CSRT" /* Core System Resource Table */ > #define ACPI_SIG_DBG2 "DBG2" /* Debug Port table type 2 */ > @@ -1624,6 +1625,55 @@ struct acpi_ibft_target { > u16 reverse_chap_secret_offset; > }; > > +/******************************************************************************* > + * > + * CEDT - CXL Early Discovery Table (ACPI 6.4) > + * Version 1 > + * > + ******************************************************************************/ > + > +struct acpi_table_cedt { > + struct acpi_table_header header; /* Common ACPI table header */ > + u32 reserved; > +}; > + > +/* Values for CEDT structure types */ > + > +enum acpi_cedt_type { > + ACPI_CEDT_TYPE_HOST_BRIDGE = 0, /* CHBS - CXL Host Bridge Structure */ > +}; > + > +struct acpi_cedt_structure { > + u8 type; > + u8 reserved; > + u16 length; > +}; > + > +/* > + * CEDT Structures, correspond to Type in struct acpi_cedt_structure > + */ > + > +/* 0: CXL Host Bridge Structure */ > + > +struct acpi_cedt_chbs { > + struct acpi_cedt_structure header; > + u32 uid; > + u32 version; > + u32 reserved1; > + u64 base; > + u64 length; > +}; > + > +/* Values for version field above */ > + > +#define ACPI_CEDT_CHBS_VERSION_CXL11 (0) > +#define ACPI_CEDT_CHBS_VERSION_CXL20 (1) > + > +/* Values for length field above */ > + > +#define ACPI_CEDT_CHBS_LENGTH_CXL11 (0x2000) > +#define ACPI_CEDT_CHBS_LENGTH_CXL20 (0x10000) > + > /* Reset to default packing */ > > #pragma pack()
On Tue, Jan 12, 2021 at 10:44 AM Jonathan Cameron <Jonathan.Cameron@huawei.com> wrote: > > On Mon, 11 Jan 2021 14:51:06 -0800 > Ben Widawsky <ben.widawsky@intel.com> wrote: > > > From: Vishal Verma <vishal.l.verma@intel.com> > > > > Add an acpi_cxl module to coordinate the ACPI portions of the CXL > > (Compute eXpress Link) interconnect. This driver binds to ACPI0017 > > objects in the ACPI tree, and coordinates access to the resources > > provided by the ACPI CEDT (CXL Early Discovery Table). > > > > It also coordinates operations of the root port _OSC object to notify > > platform firmware that the OS has native support for the CXL > > capabilities of endpoints. > > > > Note: the actbl1.h changes are speculative. The expectation is that they > > will arrive through the ACPICA tree in due time. > > I would pull the ACPICA changes out into a precursor patch. > > > > > Cc: Ben Widawsky <ben.widawsky@intel.com> > > Cc: Dan Williams <dan.j.williams@intel.com> > > Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> > > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> > > Hi, > > I think it would be good to also add CEDT to the list in drivers/acpi/tables.c > so that we can dump it from /sys/firmware/acpi/tables/ and potentially > override it from an initrd. ACPICA changes will eventually come through the ACPI tree not this patch set. > > https://elixir.bootlin.com/linux/v5.11-rc3/source/drivers/acpi/tables.c#L482 > Can be very helpful whilst debugging. Related to that, anyone know if anyone > has acpica patches so we can have iasl -d work on the table? Would probably > be useful but I'd rather not duplicate work if it's already done. > The supplemental tables described here: https://www.uefi.org/acpi ...do eventually make there way into ACPICA. Added Bob and Erik in case they can comment on when CEDT and CDAT support will be picked up. > A few minor things inline > > Jonathan > > > --- > > drivers/Kconfig | 1 + > > drivers/Makefile | 1 + > > drivers/cxl/Kconfig | 36 ++++++++++++++++ > > drivers/cxl/Makefile | 5 +++ > > drivers/cxl/acpi.c | 97 +++++++++++++++++++++++++++++++++++++++++++ > > drivers/cxl/acpi.h | 15 +++++++ > > include/acpi/actbl1.h | 50 ++++++++++++++++++++++ > > 7 files changed, 205 insertions(+) > > create mode 100644 drivers/cxl/Kconfig > > create mode 100644 drivers/cxl/Makefile > > create mode 100644 drivers/cxl/acpi.c > > create mode 100644 drivers/cxl/acpi.h > > > > diff --git a/drivers/Kconfig b/drivers/Kconfig > > index dcecc9f6e33f..62c753a73651 100644 > > --- a/drivers/Kconfig > > +++ b/drivers/Kconfig > > @@ -6,6 +6,7 @@ menu "Device Drivers" > > source "drivers/amba/Kconfig" > > source "drivers/eisa/Kconfig" > > source "drivers/pci/Kconfig" > > +source "drivers/cxl/Kconfig" > > source "drivers/pcmcia/Kconfig" > > source "drivers/rapidio/Kconfig" > > > > diff --git a/drivers/Makefile b/drivers/Makefile > > index fd11b9ac4cc3..678ea810410f 100644 > > --- a/drivers/Makefile > > +++ b/drivers/Makefile > > @@ -73,6 +73,7 @@ obj-$(CONFIG_NVM) += lightnvm/ > > obj-y += base/ block/ misc/ mfd/ nfc/ > > obj-$(CONFIG_LIBNVDIMM) += nvdimm/ > > obj-$(CONFIG_DAX) += dax/ > > +obj-$(CONFIG_CXL_BUS) += cxl/ > > obj-$(CONFIG_DMA_SHARED_BUFFER) += dma-buf/ > > obj-$(CONFIG_NUBUS) += nubus/ > > obj-y += macintosh/ > > diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig > > new file mode 100644 > > index 000000000000..68da926ba5b1 > > --- /dev/null > > +++ b/drivers/cxl/Kconfig > > @@ -0,0 +1,36 @@ > > +# SPDX-License-Identifier: GPL-2.0-only > > +menuconfig CXL_BUS > > + tristate "CXL (Compute Express Link) Devices Support" > > + help > > + CXL is a bus that is electrically compatible with PCI-E, but layers > > For consistency with Kconfig in driver/pci probably better to spell PCI Express > throughout. Sure. > > > + three protocols on that signalling (CXL.io, CXL.cache, and CXL.mem). > > + The CXL.cache protocol allows devices to hold cachelines locally, the > > + CXL.mem protocol allows devices to be fully coherent memory targets, > > + the CXL.io protocol is equivalent to PCI-E. Say 'y' to enable support > > + for the configuration and management of devices supporting these > > + protocols. > > + > > +if CXL_BUS > > + > > +config CXL_BUS_PROVIDER > > + tristate > > + > > +config CXL_ACPI > > + tristate "CXL ACPI: Platform Support" > > + depends on ACPI > > + default CXL_BUS > > + select CXL_BUS_PROVIDER > > + help > > + Say 'y/m' to enable a driver (named "cxl_acpi.ko" when built > > + as a module) that will enable support for CXL.mem endpoint > > + devices. In general, CXL Platform Support is a prerequisite > > + for any CXL device driver that wants to claim ownership of a > > + component register space. By default platform firmware assumes > > + Linux is unaware of CXL capabilities and requires explicit > > + opt-in. This platform component also mediates resources > > + described by the CEDT (CXL Early Discovery Table). See > > + Chapter 9.14.1 CXL Early Discovery Table (CEDT) in the CXL 2.0 > > + specification. > > + > > + If unsure say 'm' > > +endif > > diff --git a/drivers/cxl/Makefile b/drivers/cxl/Makefile > > new file mode 100644 > > index 000000000000..d38cd34a2582 > > --- /dev/null > > +++ b/drivers/cxl/Makefile > > @@ -0,0 +1,5 @@ > > +# SPDX-License-Identifier: GPL-2.0 > > +obj-$(CONFIG_CXL_ACPI) += cxl_acpi.o > > + > > +ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=CXL > > +cxl_acpi-y := acpi.o > > diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c > > new file mode 100644 > > index 000000000000..0f1ba9b3f1ed > > --- /dev/null > > +++ b/drivers/cxl/acpi.c > > @@ -0,0 +1,97 @@ > > +// SPDX-License-Identifier: GPL-2.0-only > > +/* Copyright(c) 2020 Intel Corporation. All rights reserved. */ > > +#include <linux/platform_device.h> > > +#include <linux/list_sort.h> > > +#include <linux/module.h> > > +#include <linux/mutex.h> > > +#include <linux/sysfs.h> > > +#include <linux/list.h> > > +#include <linux/acpi.h> > > +#include <linux/sort.h> > > +#include <linux/pci.h> > > Trivial: For includes I'm fairly sure general convention (as much as there > is one is to do alphabetical order, not reverse xmas tree). No, there's no guidance for this in coding-style so it's one of those maintainer preference items. > > > +#include "acpi.h" > > + > > +/* > > + * If/when CXL support is defined by other platform firmware the kernel > > + * will need a mechanism to select between the platform specific version > > + * of this routine, until then, hard-code ACPI assumptions > > + */ > > +int cxl_bus_acquire(struct pci_dev *pdev) > > +{ > > + struct acpi_device *adev; > > + struct pci_dev *root_port; > > + struct device *root; > > + > > + root_port = pcie_find_root_port(pdev); > > + if (!root_port) > > + return -ENXIO; > > + > > + root = root_port->dev.parent; > > + if (!root) > > + return -ENXIO; > > + > > + adev = ACPI_COMPANION(root); > > + if (!adev) > > + return -ENXIO; > > + > > + /* TODO: OSC enabling */ > > + > > + return 0; > > +} > > +EXPORT_SYMBOL_GPL(cxl_bus_acquire); > > + > > +static void acpi_cedt_put_table(void *table) > > +{ > > + acpi_put_table(table); > > +} > > + > > +static int cxl_acpi_probe(struct platform_device *pdev) > > +{ > > + struct acpi_device *adev = ACPI_COMPANION(&pdev->dev); > > + struct cxl_acpi_desc *acpi_desc; > > + struct device *dev = &adev->dev; > > + struct acpi_table_header *tbl; > > + acpi_status status; > > + acpi_size sz; > > + int rc; > > + > > + status = acpi_get_table(ACPI_SIG_CEDT, 0, &tbl); > > + if (ACPI_FAILURE(status)) { > > + dev_err(dev, "failed to find CEDT at startup\n"); > > + return 0; > > + } > > + > > + rc = devm_add_action_or_reset(dev, acpi_cedt_put_table, tbl); > > + if (rc) > > + return rc; > > + > > + sz = tbl->length; > > + dev_info(dev, "found CEDT at startup: %lld bytes\n", sz); > > Is this useful? At least for my normal acpi boot I'll see CEDT in the list of > detected ACPI tables early in boot. This provides less info than that > print already has. Agree.
On Tue, 12 Jan 2021 11:43:31 -0800 Dan Williams <dan.j.williams@intel.com> wrote: > On Tue, Jan 12, 2021 at 10:44 AM Jonathan Cameron > <Jonathan.Cameron@huawei.com> wrote: > > > > On Mon, 11 Jan 2021 14:51:06 -0800 > > Ben Widawsky <ben.widawsky@intel.com> wrote: > > > > > From: Vishal Verma <vishal.l.verma@intel.com> > > > > > > Add an acpi_cxl module to coordinate the ACPI portions of the CXL > > > (Compute eXpress Link) interconnect. This driver binds to ACPI0017 > > > objects in the ACPI tree, and coordinates access to the resources > > > provided by the ACPI CEDT (CXL Early Discovery Table). > > > > > > It also coordinates operations of the root port _OSC object to notify > > > platform firmware that the OS has native support for the CXL > > > capabilities of endpoints. > > > > > > Note: the actbl1.h changes are speculative. The expectation is that they > > > will arrive through the ACPICA tree in due time. > > > > I would pull the ACPICA changes out into a precursor patch. > > > > > > > > > > Cc: Ben Widawsky <ben.widawsky@intel.com> > > > Cc: Dan Williams <dan.j.williams@intel.com> > > > Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> > > > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> > > > > Hi, > > > > I think it would be good to also add CEDT to the list in drivers/acpi/tables.c > > so that we can dump it from /sys/firmware/acpi/tables/ and potentially > > override it from an initrd. > > ACPICA changes will eventually come through the ACPI tree not this patch set. That particular file isn't from ACPICA though I value in the entry will be. > > > > > > https://elixir.bootlin.com/linux/v5.11-rc3/source/drivers/acpi/tables.c#L482 > > Can be very helpful whilst debugging. Related to that, anyone know if anyone > > has acpica patches so we can have iasl -d work on the table? Would probably > > be useful but I'd rather not duplicate work if it's already done. > > > > The supplemental tables described here: > > https://www.uefi.org/acpi > > ...do eventually make there way into ACPICA. Added Bob and Erik in > case they can comment on when CEDT and CDAT support will be picked up. ...
On Tue, Jan 12, 2021 at 1:29 AM Ben Widawsky <ben.widawsky@intel.com> wrote: > > From: Vishal Verma <vishal.l.verma@intel.com> > > Add an acpi_cxl module to coordinate the ACPI portions of the CXL > (Compute eXpress Link) interconnect. This driver binds to ACPI0017 > objects in the ACPI tree, and coordinates access to the resources > provided by the ACPI CEDT (CXL Early Discovery Table). > > It also coordinates operations of the root port _OSC object to notify > platform firmware that the OS has native support for the CXL > capabilities of endpoints. This doesn't happen here, but in the next patch. > Note: the actbl1.h changes are speculative. The expectation is that they > will arrive through the ACPICA tree in due time. So why don't you put them into a separate patch and drop it from the series when not necessary any more? > Cc: Ben Widawsky <ben.widawsky@intel.com> > Cc: Dan Williams <dan.j.williams@intel.com> > Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> > --- > drivers/Kconfig | 1 + > drivers/Makefile | 1 + > drivers/cxl/Kconfig | 36 ++++++++++++++++ > drivers/cxl/Makefile | 5 +++ > drivers/cxl/acpi.c | 97 +++++++++++++++++++++++++++++++++++++++++++ > drivers/cxl/acpi.h | 15 +++++++ > include/acpi/actbl1.h | 50 ++++++++++++++++++++++ > 7 files changed, 205 insertions(+) > create mode 100644 drivers/cxl/Kconfig > create mode 100644 drivers/cxl/Makefile > create mode 100644 drivers/cxl/acpi.c > create mode 100644 drivers/cxl/acpi.h > > diff --git a/drivers/Kconfig b/drivers/Kconfig > index dcecc9f6e33f..62c753a73651 100644 > --- a/drivers/Kconfig > +++ b/drivers/Kconfig > @@ -6,6 +6,7 @@ menu "Device Drivers" > source "drivers/amba/Kconfig" > source "drivers/eisa/Kconfig" > source "drivers/pci/Kconfig" > +source "drivers/cxl/Kconfig" > source "drivers/pcmcia/Kconfig" > source "drivers/rapidio/Kconfig" > > diff --git a/drivers/Makefile b/drivers/Makefile > index fd11b9ac4cc3..678ea810410f 100644 > --- a/drivers/Makefile > +++ b/drivers/Makefile > @@ -73,6 +73,7 @@ obj-$(CONFIG_NVM) += lightnvm/ > obj-y += base/ block/ misc/ mfd/ nfc/ > obj-$(CONFIG_LIBNVDIMM) += nvdimm/ > obj-$(CONFIG_DAX) += dax/ > +obj-$(CONFIG_CXL_BUS) += cxl/ > obj-$(CONFIG_DMA_SHARED_BUFFER) += dma-buf/ > obj-$(CONFIG_NUBUS) += nubus/ > obj-y += macintosh/ > diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig > new file mode 100644 > index 000000000000..68da926ba5b1 > --- /dev/null > +++ b/drivers/cxl/Kconfig > @@ -0,0 +1,36 @@ > +# SPDX-License-Identifier: GPL-2.0-only > +menuconfig CXL_BUS > + tristate "CXL (Compute Express Link) Devices Support" > + help > + CXL is a bus that is electrically compatible with PCI-E, but layers > + three protocols on that signalling (CXL.io, CXL.cache, and CXL.mem). > + The CXL.cache protocol allows devices to hold cachelines locally, the > + CXL.mem protocol allows devices to be fully coherent memory targets, > + the CXL.io protocol is equivalent to PCI-E. Say 'y' to enable support > + for the configuration and management of devices supporting these > + protocols. > + > +if CXL_BUS > + > +config CXL_BUS_PROVIDER > + tristate > + > +config CXL_ACPI > + tristate "CXL ACPI: Platform Support" > + depends on ACPI > + default CXL_BUS > + select CXL_BUS_PROVIDER > + help > + Say 'y/m' to enable a driver (named "cxl_acpi.ko" when built > + as a module) that will enable support for CXL.mem endpoint > + devices. In general, CXL Platform Support is a prerequisite > + for any CXL device driver that wants to claim ownership of a > + component register space. By default platform firmware assumes > + Linux is unaware of CXL capabilities and requires explicit > + opt-in. This platform component also mediates resources > + described by the CEDT (CXL Early Discovery Table). See > + Chapter 9.14.1 CXL Early Discovery Table (CEDT) in the CXL 2.0 > + specification. > + > + If unsure say 'm' Missing full stop. > +endif > diff --git a/drivers/cxl/Makefile b/drivers/cxl/Makefile > new file mode 100644 > index 000000000000..d38cd34a2582 > --- /dev/null > +++ b/drivers/cxl/Makefile > @@ -0,0 +1,5 @@ > +# SPDX-License-Identifier: GPL-2.0 > +obj-$(CONFIG_CXL_ACPI) += cxl_acpi.o > + > +ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=CXL > +cxl_acpi-y := acpi.o > diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c > new file mode 100644 > index 000000000000..0f1ba9b3f1ed > --- /dev/null > +++ b/drivers/cxl/acpi.c > @@ -0,0 +1,97 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* Copyright(c) 2020 Intel Corporation. All rights reserved. */ > +#include <linux/platform_device.h> > +#include <linux/list_sort.h> > +#include <linux/module.h> > +#include <linux/mutex.h> > +#include <linux/sysfs.h> > +#include <linux/list.h> > +#include <linux/acpi.h> > +#include <linux/sort.h> > +#include <linux/pci.h> > +#include "acpi.h" > + > +/* > + * If/when CXL support is defined by other platform firmware the kernel > + * will need a mechanism to select between the platform specific version > + * of this routine, until then, hard-code ACPI assumptions > + */ > +int cxl_bus_acquire(struct pci_dev *pdev) > +{ > + struct acpi_device *adev; > + struct pci_dev *root_port; > + struct device *root; > + > + root_port = pcie_find_root_port(pdev); > + if (!root_port) > + return -ENXIO; > + > + root = root_port->dev.parent; > + if (!root) > + return -ENXIO; > + > + adev = ACPI_COMPANION(root); > + if (!adev) > + return -ENXIO; > + > + /* TODO: OSC enabling */ > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(cxl_bus_acquire); I would move the addition of cxl_bus_acquire() entirely to the next patch, it looks quite confusing to me as is. > + > +static void acpi_cedt_put_table(void *table) > +{ > + acpi_put_table(table); > +} > + > +static int cxl_acpi_probe(struct platform_device *pdev) > +{ > + struct acpi_device *adev = ACPI_COMPANION(&pdev->dev); > + struct cxl_acpi_desc *acpi_desc; > + struct device *dev = &adev->dev; > + struct acpi_table_header *tbl; > + acpi_status status; > + acpi_size sz; > + int rc; > + > + status = acpi_get_table(ACPI_SIG_CEDT, 0, &tbl); > + if (ACPI_FAILURE(status)) { > + dev_err(dev, "failed to find CEDT at startup\n"); > + return 0; > + } > + > + rc = devm_add_action_or_reset(dev, acpi_cedt_put_table, tbl); > + if (rc) > + return rc; > + > + sz = tbl->length; > + dev_info(dev, "found CEDT at startup: %lld bytes\n", sz); > + > + acpi_desc = devm_kzalloc(dev, sizeof(*acpi_desc), GFP_KERNEL); > + if (!acpi_desc) > + return -ENOMEM; > + > + dev_set_drvdata(&adev->dev, acpi_desc); > + acpi_desc->dev = &adev->dev; > + acpi_desc->acpi_header = *tbl; > + > + return 0; > +} > + > +static const struct acpi_device_id cxl_acpi_ids[] = { > + { "ACPI0017", 0 }, > + { "", 0 }, > +}; > +MODULE_DEVICE_TABLE(acpi, cxl_acpi_ids); > + > +static struct platform_driver cxl_acpi_driver = { > + .probe = cxl_acpi_probe, > + .driver = { > + .name = KBUILD_MODNAME, > + .acpi_match_table = cxl_acpi_ids, > + }, > +}; > + > +module_platform_driver(cxl_acpi_driver); > +MODULE_LICENSE("GPL v2"); > diff --git a/drivers/cxl/acpi.h b/drivers/cxl/acpi.h > new file mode 100644 > index 000000000000..d638f8886ab7 > --- /dev/null > +++ b/drivers/cxl/acpi.h > @@ -0,0 +1,15 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* Copyright(c) 2020 Intel Corporation. All rights reserved. */ > + > +#ifndef __CXL_ACPI_H__ > +#define __CXL_ACPI_H__ > +#include <linux/acpi.h> > + > +struct cxl_acpi_desc { > + struct acpi_table_header acpi_header; > + struct device *dev; > +}; > + > +int cxl_bus_acquire(struct pci_dev *pci_dev); And so this should go to the next patch too IMV. > + > +#endif /* __CXL_ACPI_H__ */ > diff --git a/include/acpi/actbl1.h b/include/acpi/actbl1.h > index 43549547ed3e..f3a0303984c8 100644 > --- a/include/acpi/actbl1.h > +++ b/include/acpi/actbl1.h > @@ -28,6 +28,7 @@ > #define ACPI_SIG_BERT "BERT" /* Boot Error Record Table */ > #define ACPI_SIG_BGRT "BGRT" /* Boot Graphics Resource Table */ > #define ACPI_SIG_BOOT "BOOT" /* Simple Boot Flag Table */ > +#define ACPI_SIG_CEDT "CEDT" /* CXL Early Discovery Table */ > #define ACPI_SIG_CPEP "CPEP" /* Corrected Platform Error Polling table */ > #define ACPI_SIG_CSRT "CSRT" /* Core System Resource Table */ > #define ACPI_SIG_DBG2 "DBG2" /* Debug Port table type 2 */ > @@ -1624,6 +1625,55 @@ struct acpi_ibft_target { > u16 reverse_chap_secret_offset; > }; > > +/******************************************************************************* > + * > + * CEDT - CXL Early Discovery Table (ACPI 6.4) > + * Version 1 > + * > + ******************************************************************************/ > + > +struct acpi_table_cedt { > + struct acpi_table_header header; /* Common ACPI table header */ > + u32 reserved; > +}; > + > +/* Values for CEDT structure types */ > + > +enum acpi_cedt_type { > + ACPI_CEDT_TYPE_HOST_BRIDGE = 0, /* CHBS - CXL Host Bridge Structure */ > +}; > + > +struct acpi_cedt_structure { > + u8 type; > + u8 reserved; > + u16 length; > +}; > + > +/* > + * CEDT Structures, correspond to Type in struct acpi_cedt_structure > + */ > + > +/* 0: CXL Host Bridge Structure */ > + > +struct acpi_cedt_chbs { > + struct acpi_cedt_structure header; > + u32 uid; > + u32 version; > + u32 reserved1; > + u64 base; > + u64 length; > +}; > + > +/* Values for version field above */ > + > +#define ACPI_CEDT_CHBS_VERSION_CXL11 (0) > +#define ACPI_CEDT_CHBS_VERSION_CXL20 (1) > + > +/* Values for length field above */ > + > +#define ACPI_CEDT_CHBS_LENGTH_CXL11 (0x2000) > +#define ACPI_CEDT_CHBS_LENGTH_CXL20 (0x10000) > + > /* Reset to default packing */ > > #pragma pack() > -- > 2.30.0 >
> -----Original Message----- > From: Dan Williams <dan.j.williams@intel.com> > Sent: Tuesday, January 12, 2021 11:44 AM > To: Jonathan Cameron <Jonathan.Cameron@huawei.com> > Cc: Widawsky, Ben <ben.widawsky@intel.com>; linux-cxl@vger.kernel.org; > Verma, Vishal L <vishal.l.verma@intel.com>; Linux Kernel Mailing List <linux- > kernel@vger.kernel.org>; Linux PCI <linux-pci@vger.kernel.org>; Weiny, Ira > <ira.weiny@intel.com>; Kelley, Sean V <sean.v.kelley@intel.com>; Wysocki, > Rafael J <rafael.j.wysocki@intel.com>; Bjorn Helgaas <helgaas@kernel.org>; > Jon Masters <jcm@jonmasters.org>; Chris Browy <cbrowy@avery- > design.com>; Randy Dunlap <rdunlap@infradead.org>; Christoph Hellwig > <hch@infradead.org>; daniel.lll@alibaba-inc.com; Moore, Robert > <robert.moore@intel.com>; Kaneda, Erik <erik.kaneda@intel.com> > Subject: Re: [RFC PATCH v3 02/16] cxl/acpi: Add an acpi_cxl module for the > CXL interconnect > > On Tue, Jan 12, 2021 at 10:44 AM Jonathan Cameron > <Jonathan.Cameron@huawei.com> wrote: > > > > On Mon, 11 Jan 2021 14:51:06 -0800 > > Ben Widawsky <ben.widawsky@intel.com> wrote: > > > > > From: Vishal Verma <vishal.l.verma@intel.com> > > > > > > Add an acpi_cxl module to coordinate the ACPI portions of the CXL > > > (Compute eXpress Link) interconnect. This driver binds to ACPI0017 > > > objects in the ACPI tree, and coordinates access to the resources > > > provided by the ACPI CEDT (CXL Early Discovery Table). > > > > > > It also coordinates operations of the root port _OSC object to notify > > > platform firmware that the OS has native support for the CXL > > > capabilities of endpoints. > > > > > > Note: the actbl1.h changes are speculative. The expectation is that they > > > will arrive through the ACPICA tree in due time. > > > > I would pull the ACPICA changes out into a precursor patch. > > > > > > > > > > Cc: Ben Widawsky <ben.widawsky@intel.com> > > > Cc: Dan Williams <dan.j.williams@intel.com> > > > Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> > > > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> > > > > Hi, > > > > I think it would be good to also add CEDT to the list in drivers/acpi/tables.c > > so that we can dump it from /sys/firmware/acpi/tables/ and potentially > > override it from an initrd. > > ACPICA changes will eventually come through the ACPI tree not this patch > set. > > > > > > https://elixir.bootlin.com/linux/v5.11- > rc3/source/drivers/acpi/tables.c#L482 > > Can be very helpful whilst debugging. Related to that, anyone know if > anyone > > has acpica patches so we can have iasl -d work on the table? Would > probably > > be useful but I'd rather not duplicate work if it's already done. > > > > The supplemental tables described here: > > https://www.uefi.org/acpi > > ...do eventually make there way into ACPICA. Added Bob and Erik in > case they can comment on when CEDT and CDAT support will be picked up. We would be happy to add support. I think Ben has reached out to me earlier about something like this but I haven’t had a chance to implement... Sorry about the delay.. How soon is the iASL/ACPICA support needed for CDAT and CDET? Erik
On Tue, 2021-01-12 at 18:43 +0000, Jonathan Cameron wrote: > On Mon, 11 Jan 2021 14:51:06 -0800 > Ben Widawsky <ben.widawsky@intel.com> wrote: > > > From: Vishal Verma <vishal.l.verma@intel.com> > > > > Add an acpi_cxl module to coordinate the ACPI portions of the CXL > > (Compute eXpress Link) interconnect. This driver binds to ACPI0017 > > objects in the ACPI tree, and coordinates access to the resources > > provided by the ACPI CEDT (CXL Early Discovery Table). > > > > It also coordinates operations of the root port _OSC object to notify > > platform firmware that the OS has native support for the CXL > > capabilities of endpoints. > > > > Note: the actbl1.h changes are speculative. The expectation is that they > > will arrive through the ACPICA tree in due time. > > I would pull the ACPICA changes out into a precursor patch. Done. > > > > > Cc: Ben Widawsky <ben.widawsky@intel.com> > > Cc: Dan Williams <dan.j.williams@intel.com> > > Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> > > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> > > Hi, > > I think it would be good to also add CEDT to the list in drivers/acpi/tables.c > so that we can dump it from /sys/firmware/acpi/tables/ and potentially > override it from an initrd. Dumping it from /sys/firmware/acpi/tables already works, but I did add it to tables.c so it can also be overridden. I did this in a separate patch, in case ACPI folks want to do this differently. > > https://elixir.bootlin.com/linux/v5.11-rc3/source/drivers/acpi/tables.c#L482 > Can be very helpful whilst debugging. Related to that, anyone know if anyone > has acpica patches so we can have iasl -d work on the table? Would probably > be useful but I'd rather not duplicate work if it's already done. > > A few minor things inline Agreed with all of your other comments below, and I've addresed them for the next revision. Thanks for the review Jonathan! > > Jonathan > >
On Wed, 2021-01-13 at 13:40 +0100, Rafael J. Wysocki wrote: > On Tue, Jan 12, 2021 at 1:29 AM Ben Widawsky <ben.widawsky@intel.com> wrote: > > > > From: Vishal Verma <vishal.l.verma@intel.com> > > > > Add an acpi_cxl module to coordinate the ACPI portions of the CXL > > (Compute eXpress Link) interconnect. This driver binds to ACPI0017 > > objects in the ACPI tree, and coordinates access to the resources > > provided by the ACPI CEDT (CXL Early Discovery Table). > > > > It also coordinates operations of the root port _OSC object to notify > > platform firmware that the OS has native support for the CXL > > capabilities of endpoints. > > This doesn't happen here, but in the next patch. > > > Note: the actbl1.h changes are speculative. The expectation is that they > > will arrive through the ACPICA tree in due time. > > So why don't you put them into a separate patch and drop it from the > series when not necessary any more? [snip] > > +/* > > + * If/when CXL support is defined by other platform firmware the kernel > > + * will need a mechanism to select between the platform specific version > > + * of this routine, until then, hard-code ACPI assumptions > > + */ > > +int cxl_bus_acquire(struct pci_dev *pdev) > > +{ > > + struct acpi_device *adev; > > + struct pci_dev *root_port; > > + struct device *root; > > + > > + root_port = pcie_find_root_port(pdev); > > + if (!root_port) > > + return -ENXIO; > > + > > + root = root_port->dev.parent; > > + if (!root) > > + return -ENXIO; > > + > > + adev = ACPI_COMPANION(root); > > + if (!adev) > > + return -ENXIO; > > + > > + /* TODO: OSC enabling */ > > + > > + return 0; > > +} > > +EXPORT_SYMBOL_GPL(cxl_bus_acquire); > > I would move the addition of cxl_bus_acquire() entirely to the next > patch, it looks quite confusing to me as is. Makes sense - and also agreed with all of your other comments. I've cleaned this up for the next revision. Thanks Rafael! >
On Wed, Jan 13, 2021 at 9:55 AM Kaneda, Erik <erik.kaneda@intel.com> wrote: [..] > > The supplemental tables described here: > > > > https://www.uefi.org/acpi > > > > ...do eventually make there way into ACPICA. Added Bob and Erik in > > case they can comment on when CEDT and CDAT support will be picked up. > > We would be happy to add support. I think Ben has reached out to me earlier about something like this but I haven’t had a chance to implement... Sorry about the delay.. How soon is the iASL/ACPICA support needed for CDAT and CDET? CDAT and CEDT definitions in include/acpi/actbl* would be useful as soon as v5.12. If that's too soon I don't think we're blocked, but the driver is fast approaching the point where it needs to consult these tables to enable higher order functionality.
diff --git a/drivers/Kconfig b/drivers/Kconfig index dcecc9f6e33f..62c753a73651 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -6,6 +6,7 @@ menu "Device Drivers" source "drivers/amba/Kconfig" source "drivers/eisa/Kconfig" source "drivers/pci/Kconfig" +source "drivers/cxl/Kconfig" source "drivers/pcmcia/Kconfig" source "drivers/rapidio/Kconfig" diff --git a/drivers/Makefile b/drivers/Makefile index fd11b9ac4cc3..678ea810410f 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -73,6 +73,7 @@ obj-$(CONFIG_NVM) += lightnvm/ obj-y += base/ block/ misc/ mfd/ nfc/ obj-$(CONFIG_LIBNVDIMM) += nvdimm/ obj-$(CONFIG_DAX) += dax/ +obj-$(CONFIG_CXL_BUS) += cxl/ obj-$(CONFIG_DMA_SHARED_BUFFER) += dma-buf/ obj-$(CONFIG_NUBUS) += nubus/ obj-y += macintosh/ diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig new file mode 100644 index 000000000000..68da926ba5b1 --- /dev/null +++ b/drivers/cxl/Kconfig @@ -0,0 +1,36 @@ +# SPDX-License-Identifier: GPL-2.0-only +menuconfig CXL_BUS + tristate "CXL (Compute Express Link) Devices Support" + help + CXL is a bus that is electrically compatible with PCI-E, but layers + three protocols on that signalling (CXL.io, CXL.cache, and CXL.mem). + The CXL.cache protocol allows devices to hold cachelines locally, the + CXL.mem protocol allows devices to be fully coherent memory targets, + the CXL.io protocol is equivalent to PCI-E. Say 'y' to enable support + for the configuration and management of devices supporting these + protocols. + +if CXL_BUS + +config CXL_BUS_PROVIDER + tristate + +config CXL_ACPI + tristate "CXL ACPI: Platform Support" + depends on ACPI + default CXL_BUS + select CXL_BUS_PROVIDER + help + Say 'y/m' to enable a driver (named "cxl_acpi.ko" when built + as a module) that will enable support for CXL.mem endpoint + devices. In general, CXL Platform Support is a prerequisite + for any CXL device driver that wants to claim ownership of a + component register space. By default platform firmware assumes + Linux is unaware of CXL capabilities and requires explicit + opt-in. This platform component also mediates resources + described by the CEDT (CXL Early Discovery Table). See + Chapter 9.14.1 CXL Early Discovery Table (CEDT) in the CXL 2.0 + specification. + + If unsure say 'm' +endif diff --git a/drivers/cxl/Makefile b/drivers/cxl/Makefile new file mode 100644 index 000000000000..d38cd34a2582 --- /dev/null +++ b/drivers/cxl/Makefile @@ -0,0 +1,5 @@ +# SPDX-License-Identifier: GPL-2.0 +obj-$(CONFIG_CXL_ACPI) += cxl_acpi.o + +ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=CXL +cxl_acpi-y := acpi.o diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c new file mode 100644 index 000000000000..0f1ba9b3f1ed --- /dev/null +++ b/drivers/cxl/acpi.c @@ -0,0 +1,97 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright(c) 2020 Intel Corporation. All rights reserved. */ +#include <linux/platform_device.h> +#include <linux/list_sort.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/sysfs.h> +#include <linux/list.h> +#include <linux/acpi.h> +#include <linux/sort.h> +#include <linux/pci.h> +#include "acpi.h" + +/* + * If/when CXL support is defined by other platform firmware the kernel + * will need a mechanism to select between the platform specific version + * of this routine, until then, hard-code ACPI assumptions + */ +int cxl_bus_acquire(struct pci_dev *pdev) +{ + struct acpi_device *adev; + struct pci_dev *root_port; + struct device *root; + + root_port = pcie_find_root_port(pdev); + if (!root_port) + return -ENXIO; + + root = root_port->dev.parent; + if (!root) + return -ENXIO; + + adev = ACPI_COMPANION(root); + if (!adev) + return -ENXIO; + + /* TODO: OSC enabling */ + + return 0; +} +EXPORT_SYMBOL_GPL(cxl_bus_acquire); + +static void acpi_cedt_put_table(void *table) +{ + acpi_put_table(table); +} + +static int cxl_acpi_probe(struct platform_device *pdev) +{ + struct acpi_device *adev = ACPI_COMPANION(&pdev->dev); + struct cxl_acpi_desc *acpi_desc; + struct device *dev = &adev->dev; + struct acpi_table_header *tbl; + acpi_status status; + acpi_size sz; + int rc; + + status = acpi_get_table(ACPI_SIG_CEDT, 0, &tbl); + if (ACPI_FAILURE(status)) { + dev_err(dev, "failed to find CEDT at startup\n"); + return 0; + } + + rc = devm_add_action_or_reset(dev, acpi_cedt_put_table, tbl); + if (rc) + return rc; + + sz = tbl->length; + dev_info(dev, "found CEDT at startup: %lld bytes\n", sz); + + acpi_desc = devm_kzalloc(dev, sizeof(*acpi_desc), GFP_KERNEL); + if (!acpi_desc) + return -ENOMEM; + + dev_set_drvdata(&adev->dev, acpi_desc); + acpi_desc->dev = &adev->dev; + acpi_desc->acpi_header = *tbl; + + return 0; +} + +static const struct acpi_device_id cxl_acpi_ids[] = { + { "ACPI0017", 0 }, + { "", 0 }, +}; +MODULE_DEVICE_TABLE(acpi, cxl_acpi_ids); + +static struct platform_driver cxl_acpi_driver = { + .probe = cxl_acpi_probe, + .driver = { + .name = KBUILD_MODNAME, + .acpi_match_table = cxl_acpi_ids, + }, +}; + +module_platform_driver(cxl_acpi_driver); +MODULE_LICENSE("GPL v2"); diff --git a/drivers/cxl/acpi.h b/drivers/cxl/acpi.h new file mode 100644 index 000000000000..d638f8886ab7 --- /dev/null +++ b/drivers/cxl/acpi.h @@ -0,0 +1,15 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* Copyright(c) 2020 Intel Corporation. All rights reserved. */ + +#ifndef __CXL_ACPI_H__ +#define __CXL_ACPI_H__ +#include <linux/acpi.h> + +struct cxl_acpi_desc { + struct acpi_table_header acpi_header; + struct device *dev; +}; + +int cxl_bus_acquire(struct pci_dev *pci_dev); + +#endif /* __CXL_ACPI_H__ */ diff --git a/include/acpi/actbl1.h b/include/acpi/actbl1.h index 43549547ed3e..f3a0303984c8 100644 --- a/include/acpi/actbl1.h +++ b/include/acpi/actbl1.h @@ -28,6 +28,7 @@ #define ACPI_SIG_BERT "BERT" /* Boot Error Record Table */ #define ACPI_SIG_BGRT "BGRT" /* Boot Graphics Resource Table */ #define ACPI_SIG_BOOT "BOOT" /* Simple Boot Flag Table */ +#define ACPI_SIG_CEDT "CEDT" /* CXL Early Discovery Table */ #define ACPI_SIG_CPEP "CPEP" /* Corrected Platform Error Polling table */ #define ACPI_SIG_CSRT "CSRT" /* Core System Resource Table */ #define ACPI_SIG_DBG2 "DBG2" /* Debug Port table type 2 */ @@ -1624,6 +1625,55 @@ struct acpi_ibft_target { u16 reverse_chap_secret_offset; }; +/******************************************************************************* + * + * CEDT - CXL Early Discovery Table (ACPI 6.4) + * Version 1 + * + ******************************************************************************/ + +struct acpi_table_cedt { + struct acpi_table_header header; /* Common ACPI table header */ + u32 reserved; +}; + +/* Values for CEDT structure types */ + +enum acpi_cedt_type { + ACPI_CEDT_TYPE_HOST_BRIDGE = 0, /* CHBS - CXL Host Bridge Structure */ +}; + +struct acpi_cedt_structure { + u8 type; + u8 reserved; + u16 length; +}; + +/* + * CEDT Structures, correspond to Type in struct acpi_cedt_structure + */ + +/* 0: CXL Host Bridge Structure */ + +struct acpi_cedt_chbs { + struct acpi_cedt_structure header; + u32 uid; + u32 version; + u32 reserved1; + u64 base; + u64 length; +}; + +/* Values for version field above */ + +#define ACPI_CEDT_CHBS_VERSION_CXL11 (0) +#define ACPI_CEDT_CHBS_VERSION_CXL20 (1) + +/* Values for length field above */ + +#define ACPI_CEDT_CHBS_LENGTH_CXL11 (0x2000) +#define ACPI_CEDT_CHBS_LENGTH_CXL20 (0x10000) + /* Reset to default packing */ #pragma pack()