On Tue, Jan 12, 2021 at 10:44 AM Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> wrote: > > On Mon, 11 Jan 2021 14:51:06 -0800 > Ben Widawsky <ben.widawsky@xxxxxxxxx> wrote: > > > From: Vishal Verma <vishal.l.verma@xxxxxxxxx> > > > > 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@xxxxxxxxx> > > Cc: Dan Williams <dan.j.williams@xxxxxxxxx> > > Signed-off-by: Vishal Verma <vishal.l.verma@xxxxxxxxx> > > Signed-off-by: Ben Widawsky <ben.widawsky@xxxxxxxxx> > > 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.
