From f6b8ab32e3ec48ecc02d1b4a42ee03576040ddd2 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 14 Jun 2023 18:30:07 -0700 Subject: cxl/memdev: Make mailbox functionality optional In support of the Linux CXL core scaling for a wider set of CXL devices, allow for the creation of memdevs with some memory device capabilities disabled. Specifically, allow for CXL devices outside of those claiming to be compliant with the generic CXL memory device class code, like vendor specific Type-2/3 devices that host CXL.mem. This implies, allow for the creation of memdevs that only support component-registers, not necessarily memory-device-registers (like mailbox registers). A memdev derived from a CXL endpoint that does not support generic class code expectations is tagged "CXL_DEVTYPE_DEVMEM", while a memdev derived from a class-code compliant endpoint is tagged "CXL_DEVTYPE_CLASSMEM". The primary assumption of a CXL_DEVTYPE_DEVMEM memdev is that it optionally may not host a mailbox. Disable the command passthrough ioctl for memdevs that are not CXL_DEVTYPE_CLASSMEM, and return empty strings from memdev attributes associated with data retrieved via the class-device-standard IDENTIFY command. Note that empty strings were chosen over attribute visibility to maintain compatibility with shipping versions of cxl-cli that expect those attributes to always be present. Once cxl-cli has dropped that requirement this workaround can be deprecated. Reviewed-by: Jonathan Cameron Reviewed-by: Dave Jiang Link: https://lore.kernel.org/r/168679260782.3436160.7587293613945445365.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams --- drivers/cxl/cxlmem.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'drivers/cxl/cxlmem.h') diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h index b1a72e01e4de..1b39afeb369e 100644 --- a/drivers/cxl/cxlmem.h +++ b/drivers/cxl/cxlmem.h @@ -254,6 +254,20 @@ struct cxl_poison_state { struct mutex lock; /* Protect reads of poison list */ }; +/* + * enum cxl_devtype - delineate type-2 from a generic type-3 device + * @CXL_DEVTYPE_DEVMEM - Vendor specific CXL Type-2 device implementing HDM-D or + * HDM-DB, no requirement that this device implements a + * mailbox, or other memory-device-standard manageability + * flows. + * @CXL_DEVTYPE_CLASSMEM - Common class definition of a CXL Type-3 device with + * HDM-H and class-mandatory memory device registers + */ +enum cxl_devtype { + CXL_DEVTYPE_DEVMEM, + CXL_DEVTYPE_CLASSMEM, +}; + /** * struct cxl_dev_state - The driver device state * @@ -272,6 +286,7 @@ struct cxl_poison_state { * @ram_res: Active Volatile memory capacity configuration * @component_reg_phys: register base of component registers * @serial: PCIe Device Serial Number + * @type: Generic Memory Class device or Vendor Specific Memory device */ struct cxl_dev_state { struct device *dev; @@ -285,6 +300,7 @@ struct cxl_dev_state { struct resource ram_res; resource_size_t component_reg_phys; u64 serial; + enum cxl_devtype type; }; /** @@ -343,6 +359,8 @@ struct cxl_memdev_state { static inline struct cxl_memdev_state * to_cxl_memdev_state(struct cxl_dev_state *cxlds) { + if (cxlds->type != CXL_DEVTYPE_CLASSMEM) + return NULL; return container_of(cxlds, struct cxl_memdev_state, cxlds); } -- cgit v1.2.3