diff options
| -rw-r--r-- | Documentation/driver-api/cxl/index.rst | 12 | ||||
| -rw-r--r-- | Documentation/driver-api/cxl/memory-devices.rst | 15 | ||||
| -rw-r--r-- | Documentation/driver-api/index.rst | 1 | ||||
| -rw-r--r-- | drivers/Kconfig | 1 | ||||
| -rw-r--r-- | drivers/Makefile | 1 | ||||
| -rw-r--r-- | drivers/cxl/Kconfig | 35 | ||||
| -rw-r--r-- | drivers/cxl/Makefile | 4 | ||||
| -rw-r--r-- | drivers/cxl/mem.c | 62 | ||||
| -rw-r--r-- | drivers/cxl/pci.h | 17 | ||||
| -rw-r--r-- | include/linux/pci_ids.h | 1 |
10 files changed, 149 insertions, 0 deletions
diff --git a/Documentation/driver-api/cxl/index.rst b/Documentation/driver-api/cxl/index.rst new file mode 100644 index 000000000000..036e49553542 --- /dev/null +++ b/Documentation/driver-api/cxl/index.rst @@ -0,0 +1,12 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==================== +Compute Express Link +==================== + +.. toctree:: + :maxdepth: 1 + + memory-devices + +.. only:: subproject and html diff --git a/Documentation/driver-api/cxl/memory-devices.rst b/Documentation/driver-api/cxl/memory-devices.rst new file mode 100644 index 000000000000..71617e9002f1 --- /dev/null +++ b/Documentation/driver-api/cxl/memory-devices.rst @@ -0,0 +1,15 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +=================================== +Compute Express Link Memory Devices +=================================== + +A Compute Express Link Memory Device is a CXL component that implements the +CXL.mem protocol. It contains some amount of volatile memory, persistent memory, +or both. It is enumerated as a PCI device for configuration and passing +messages over an MMIO mailbox. Its contribution to the System Physical +Address space is handled via HDM (Host Managed Device Memory) decoders +that optionally define a device's contribution to an interleaved address +range across multiple devices underneath a host-bridge or interleaved +across host-bridges. diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst index 2456d0a97ed8..d246a18fd78f 100644 --- a/Documentation/driver-api/index.rst +++ b/Documentation/driver-api/index.rst @@ -35,6 +35,7 @@ available subsections can be seen below. usb/index firewire pci/index + cxl/index spi i2c ipmb 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..9e80b311e928 --- /dev/null +++ b/drivers/cxl/Kconfig @@ -0,0 +1,35 @@ +# SPDX-License-Identifier: GPL-2.0-only +menuconfig CXL_BUS + tristate "CXL (Compute Express Link) Devices Support" + depends on PCI + help + CXL is a bus that is electrically compatible with PCI Express, 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 Express. + Say 'y' to enable support for the configuration and management of + devices supporting these protocols. + +if CXL_BUS + +config CXL_MEM + tristate "CXL.mem: Memory Devices" + help + The CXL.mem protocol allows a device to act as a provider of + "System RAM" and/or "Persistent Memory" that is fully coherent + as if the memory was attached to the typical CPU memory + controller. + + Say 'y/m' to enable a driver (named "cxl_mem.ko" when built as + a module) that will attach to CXL.mem devices for + configuration, provisioning, and health monitoring. This + driver is required for dynamic provisioning of CXL.mem + attached memory which is a prerequisite for persistent memory + support. Typically volatile memory is mapped by platform + firmware and included in the platform memory map, but in some + cases the OS is responsible for mapping that memory. See + Chapter 2.3 Type 3 CXL Device 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..4a30f7c3fc4a --- /dev/null +++ b/drivers/cxl/Makefile @@ -0,0 +1,4 @@ +# SPDX-License-Identifier: GPL-2.0 +obj-$(CONFIG_CXL_MEM) += cxl_mem.o + +cxl_mem-y := mem.o diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c new file mode 100644 index 000000000000..ce33c5ee77c9 --- /dev/null +++ b/drivers/cxl/mem.c @@ -0,0 +1,62 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright(c) 2020 Intel Corporation. All rights reserved. */ +#include <linux/module.h> +#include <linux/pci.h> +#include <linux/io.h> +#include "pci.h" + +static int cxl_mem_dvsec(struct pci_dev *pdev, int dvsec) +{ + int pos; + + pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DVSEC); + if (!pos) + return 0; + + while (pos) { + u16 vendor, id; + + pci_read_config_word(pdev, pos + PCI_DVSEC_HEADER1, &vendor); + pci_read_config_word(pdev, pos + PCI_DVSEC_HEADER2, &id); + if (vendor == PCI_DVSEC_VENDOR_ID_CXL && dvsec == id) + return pos; + + pos = pci_find_next_ext_capability(pdev, pos, + PCI_EXT_CAP_ID_DVSEC); + } + + return 0; +} + +static int cxl_mem_probe(struct pci_dev *pdev, const struct pci_device_id *id) +{ + struct device *dev = &pdev->dev; + int regloc; + + regloc = cxl_mem_dvsec(pdev, PCI_DVSEC_ID_CXL_REGLOC_OFFSET); + if (!regloc) { + dev_err(dev, "register location dvsec not found\n"); + return -ENXIO; + } + + return 0; +} + +static const struct pci_device_id cxl_mem_pci_tbl[] = { + /* PCI class code for CXL.mem Type-3 Devices */ + { PCI_DEVICE_CLASS((PCI_CLASS_MEMORY_CXL << 8 | CXL_MEMORY_PROGIF), ~0)}, + { /* terminate list */ }, +}; +MODULE_DEVICE_TABLE(pci, cxl_mem_pci_tbl); + +static struct pci_driver cxl_mem_driver = { + .name = KBUILD_MODNAME, + .id_table = cxl_mem_pci_tbl, + .probe = cxl_mem_probe, + .driver = { + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + }, +}; + +MODULE_LICENSE("GPL v2"); +module_pci_driver(cxl_mem_driver); diff --git a/drivers/cxl/pci.h b/drivers/cxl/pci.h new file mode 100644 index 000000000000..e464bea3f4d3 --- /dev/null +++ b/drivers/cxl/pci.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* Copyright(c) 2020 Intel Corporation. All rights reserved. */ +#ifndef __CXL_PCI_H__ +#define __CXL_PCI_H__ + +#define CXL_MEMORY_PROGIF 0x10 + +/* + * See section 8.1 Configuration Space Registers in the CXL 2.0 + * Specification + */ +#define PCI_DVSEC_VENDOR_ID_CXL 0x1E98 +#define PCI_DVSEC_ID_CXL 0x0 + +#define PCI_DVSEC_ID_CXL_REGLOC_OFFSET 0x8 + +#endif /* __CXL_PCI_H__ */ diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h index d8156a5dbee8..766260a9b247 100644 --- a/include/linux/pci_ids.h +++ b/include/linux/pci_ids.h @@ -51,6 +51,7 @@ #define PCI_BASE_CLASS_MEMORY 0x05 #define PCI_CLASS_MEMORY_RAM 0x0500 #define PCI_CLASS_MEMORY_FLASH 0x0501 +#define PCI_CLASS_MEMORY_CXL 0x0502 #define PCI_CLASS_MEMORY_OTHER 0x0580 #define PCI_BASE_CLASS_BRIDGE 0x06 |