From patchwork Fri Jan 28 00:26:57 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ben Widawsky X-Patchwork-Id: 12727585 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F0E1E2CAF; Fri, 28 Jan 2022 00:27:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1643329645; x=1674865645; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=UqDJZYM/MW5ZrhJFplO1Gfi5Eh6cWZzYP26iw4Mzfx4=; b=lWQOH2YKo9CHxsjQ6hYnAcjCSKt3YlFiylw+vJ7UVwHBL57wGTUZOmfY kiBq6Lhqx9paCe27uZR9qMU04ZFS5Lm7987Jzb4baE1t5hiGj0TtqzBeO qcDDHFhU8I51gPC4fn0x3iNxSptGYyk8ictNHazXBTI5g/Z9kAVtMlwyv w/0E+v77vPoBfjnCwaEUuzOS4l1It9NEfkd2wqDHEkF+HclvJfdgSRUjY GlIXqWB7H8hF2nCXG3bP0IPGACiCxCMfLNcv50wZeK5xsBO41cYyeBb3f OhyoGR2YgSwww/Ld25eyIfVdOPpxU514plSXIw+LtBI4Ta0BLIpR6nMWt Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10239"; a="226982069" X-IronPort-AV: E=Sophos;i="5.88,322,1635231600"; d="scan'208";a="226982069" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jan 2022 16:27:24 -0800 X-IronPort-AV: E=Sophos;i="5.88,322,1635231600"; d="scan'208";a="674909616" Received: from vrao2-mobl1.gar.corp.intel.com (HELO localhost.localdomain) ([10.252.129.6]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jan 2022 16:27:24 -0800 From: Ben Widawsky To: linux-cxl@vger.kernel.org Cc: patches@lists.linux.dev, Ben Widawsky , kernel test robot , Alison Schofield , Dan Williams , Ira Weiny , Jonathan Cameron , Vishal Verma , Bjorn Helgaas , nvdimm@lists.linux.dev, linux-pci@vger.kernel.org Subject: [PATCH v3 04/14] cxl/region: Introduce a cxl_region driver Date: Thu, 27 Jan 2022 16:26:57 -0800 Message-Id: <20220128002707.391076-5-ben.widawsky@intel.com> X-Mailer: git-send-email 2.35.0 In-Reply-To: <20220128002707.391076-1-ben.widawsky@intel.com> References: <20220128002707.391076-1-ben.widawsky@intel.com> Precedence: bulk X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The cxl_region driver is responsible for managing the HDM decoder programming in the CXL topology. Once a region is created it must be configured and bound to the driver in order to activate it. The following is a sample of how such controls might work: region=$(cat /sys/bus/cxl/devices/decoder0.0/create_region) echo $region > /sys/bus/cxl/devices/decoder0.0/create_region echo 2 > /sys/bus/cxl/devices/decoder0.0/region0.0:0/interleave echo $((256<<20)) > /sys/bus/cxl/devices/decoder0.0/region0.0:0/size echo mem0 > /sys/bus/cxl/devices/decoder0.0/region0.0:0/target0 echo mem1 > /sys/bus/cxl/devices/decoder0.0/region0.0:0/target1 echo region0.0:0 > /sys/bus/cxl/drivers/cxl_region/bind In order to handle the eventual rise in failure modes of binding a region, a new trace event is created to help track these failures for debug and reconfiguration paths in userspace. Reported-by: kernel test robot (v2) Signed-off-by: Ben Widawsky --- Changes since v2: - Add CONFIG_CXL_REGION - Check ways/granularity in sanitize --- .../driver-api/cxl/memory-devices.rst | 3 + drivers/cxl/Kconfig | 4 + drivers/cxl/Makefile | 2 + drivers/cxl/core/core.h | 1 + drivers/cxl/core/port.c | 17 +- drivers/cxl/core/region.c | 25 +- drivers/cxl/cxl.h | 31 ++ drivers/cxl/region.c | 349 ++++++++++++++++++ drivers/cxl/region.h | 4 + 9 files changed, 431 insertions(+), 5 deletions(-) create mode 100644 drivers/cxl/region.c diff --git a/Documentation/driver-api/cxl/memory-devices.rst b/Documentation/driver-api/cxl/memory-devices.rst index 66ddc58a21b1..8cb4dece5b17 100644 --- a/Documentation/driver-api/cxl/memory-devices.rst +++ b/Documentation/driver-api/cxl/memory-devices.rst @@ -364,6 +364,9 @@ CXL Core CXL Regions ----------- +.. kernel-doc:: drivers/cxl/region.c + :doc: cxl region + .. kernel-doc:: drivers/cxl/region.h :identifiers: diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig index b88ab956bb7c..742847503c16 100644 --- a/drivers/cxl/Kconfig +++ b/drivers/cxl/Kconfig @@ -98,4 +98,8 @@ config CXL_PORT default CXL_BUS tristate +config CXL_REGION + default CXL_PORT + tristate + endif diff --git a/drivers/cxl/Makefile b/drivers/cxl/Makefile index ce267ef11d93..02a4776e7ab9 100644 --- a/drivers/cxl/Makefile +++ b/drivers/cxl/Makefile @@ -5,9 +5,11 @@ obj-$(CONFIG_CXL_MEM) += cxl_mem.o obj-$(CONFIG_CXL_ACPI) += cxl_acpi.o obj-$(CONFIG_CXL_PMEM) += cxl_pmem.o obj-$(CONFIG_CXL_PORT) += cxl_port.o +obj-$(CONFIG_CXL_REGION) += cxl_region.o cxl_mem-y := mem.o cxl_pci-y := pci.o cxl_acpi-y := acpi.o cxl_pmem-y := pmem.o cxl_port-y := port.o +cxl_region-y := region.o diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h index 35fd08d560e2..b8a154da34df 100644 --- a/drivers/cxl/core/core.h +++ b/drivers/cxl/core/core.h @@ -7,6 +7,7 @@ extern const struct device_type cxl_nvdimm_bridge_type; extern const struct device_type cxl_nvdimm_type; extern const struct device_type cxl_memdev_type; +extern const struct device_type cxl_region_type; extern struct attribute_group cxl_base_attribute_group; diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c index 0826208b2bdf..0847e6ce19ef 100644 --- a/drivers/cxl/core/port.c +++ b/drivers/cxl/core/port.c @@ -9,6 +9,7 @@ #include #include #include +#include #include #include "core.h" @@ -49,6 +50,8 @@ static int cxl_device_id(struct device *dev) } if (dev->type == &cxl_memdev_type) return CXL_DEVICE_MEMORY_EXPANDER; + if (dev->type == &cxl_region_type) + return CXL_DEVICE_REGION; return 0; } @@ -1425,13 +1428,23 @@ static int cxl_bus_match(struct device *dev, struct device_driver *drv) static int cxl_bus_probe(struct device *dev) { - int rc; + int id = cxl_device_id(dev); + int rc = -ENODEV; cxl_nested_lock(dev); - rc = to_cxl_drv(dev->driver)->probe(dev); + if (id == CXL_DEVICE_REGION) { + /* Regions cannot bind until parameters are set */ + struct cxl_region *cxlr = to_cxl_region(dev); + + if (is_cxl_region_configured(cxlr)) + rc = to_cxl_drv(dev->driver)->probe(dev); + } else { + rc = to_cxl_drv(dev->driver)->probe(dev); + } cxl_nested_unlock(dev); dev_dbg(dev, "probe: %d\n", rc); + return rc; } diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index 3b48e0469fc7..784e4ba25128 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -12,6 +12,8 @@ #include #include "core.h" +#include "core.h" + /** * DOC: cxl core region * @@ -26,10 +28,27 @@ static const struct attribute_group region_interleave_group; static bool is_region_active(struct cxl_region *cxlr) { - /* TODO: Regions can't be activated yet. */ - return false; + return cxlr->active; } +/* + * Most sanity checking is left up to region binding. This does the most basic + * check to determine whether or not the core should try probing the driver. + */ +bool is_cxl_region_configured(const struct cxl_region *cxlr) +{ + /* zero sized regions aren't a thing. */ + if (cxlr->config.size <= 0) + return false; + + /* all regions have at least 1 target */ + if (!cxlr->config.targets[0]) + return false; + + return true; +} +EXPORT_SYMBOL_GPL(is_cxl_region_configured); + static void remove_target(struct cxl_region *cxlr, int target) { struct cxl_memdev *cxlmd; @@ -316,7 +335,7 @@ static const struct attribute_group *region_groups[] = { static void cxl_region_release(struct device *dev); -static const struct device_type cxl_region_type = { +const struct device_type cxl_region_type = { .name = "cxl_region", .release = cxl_region_release, .groups = region_groups diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index b9f0099c1f39..d1a8ca19c9ea 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -81,6 +81,31 @@ static inline int cxl_to_interleave_ways(u8 eniw) } } +static inline bool cxl_is_interleave_ways_valid(int iw) +{ + switch (iw) { + case 0 ... 4: + case 6: + case 8: + case 12: + case 16: + return true; + default: + return false; + } + + unreachable(); +} + +static inline bool cxl_is_interleave_granularity_valid(int ig) +{ + if (!is_power_of_2(ig)) + return false; + + /* 16K is the max */ + return ((ig >> 15) == 0); +} + /* CXL 2.0 8.2.8.1 Device Capabilities Array Register */ #define CXLDEV_CAP_ARRAY_OFFSET 0x0 #define CXLDEV_CAP_ARRAY_CAP_ID 0 @@ -199,6 +224,10 @@ void __iomem *devm_cxl_iomap_block(struct device *dev, resource_size_t addr, #define CXL_DECODER_F_ENABLE BIT(5) #define CXL_DECODER_F_MASK GENMASK(5, 0) +#define cxl_is_pmem_t3(flags) \ + (((flags) & (CXL_DECODER_F_TYPE3 | CXL_DECODER_F_PMEM)) == \ + (CXL_DECODER_F_TYPE3 | CXL_DECODER_F_PMEM)) + enum cxl_decoder_type { CXL_DECODER_ACCELERATOR = 2, CXL_DECODER_EXPANDER = 3, @@ -357,6 +386,7 @@ struct cxl_dport *devm_cxl_add_dport(struct cxl_port *port, resource_size_t component_reg_phys); struct cxl_dport *cxl_find_dport_by_dev(struct cxl_port *port, const struct device *dev); +struct cxl_port *ep_find_cxl_port(struct cxl_memdev *cxlmd, unsigned int depth); struct cxl_decoder *to_cxl_decoder(struct device *dev); bool is_root_decoder(struct device *dev); @@ -404,6 +434,7 @@ void cxl_driver_unregister(struct cxl_driver *cxl_drv); #define CXL_DEVICE_PORT 3 #define CXL_DEVICE_ROOT 4 #define CXL_DEVICE_MEMORY_EXPANDER 5 +#define CXL_DEVICE_REGION 6 #define MODULE_ALIAS_CXL(type) MODULE_ALIAS("cxl:t" __stringify(type) "*") #define CXL_MODALIAS_FMT "cxl:t%d" diff --git a/drivers/cxl/region.c b/drivers/cxl/region.c new file mode 100644 index 000000000000..cc41939a2f0a --- /dev/null +++ b/drivers/cxl/region.c @@ -0,0 +1,349 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright(c) 2021 Intel Corporation. All rights reserved. */ +#include +#include +#include +#include +#include "cxlmem.h" +#include "region.h" +#include "cxl.h" + +/** + * DOC: cxl region + * + * This module implements a region driver that is capable of programming CXL + * hardware to setup regions. + * + * A CXL region encompasses a chunk of host physical address space that may be + * consumed by a single device (x1 interleave aka linear) or across multiple + * devices (xN interleaved). The region driver has the following + * responsibilities: + * + * * Walk topology to obtain decoder resources for region configuration. + * * Program decoder resources based on region configuration. + * * Bridge CXL regions to LIBNVDIMM + * * Initiates reading and configuring LSA regions + * * Enumerates regions created by BIOS (typically volatile) + */ + +#define region_ways(region) ((region)->config.interleave_ways) +#define region_granularity(region) ((region)->config.interleave_granularity) + +static struct cxl_decoder *rootd_from_region(struct cxl_region *cxlr) +{ + struct device *d = cxlr->dev.parent; + + if (WARN_ONCE(!is_root_decoder(d), + "Corrupt topology for root region\n")) + return NULL; + + return to_cxl_decoder(d); +} + +static struct cxl_port *get_hostbridge(const struct cxl_memdev *ep) +{ + struct cxl_port *port = ep->port; + + while (!is_cxl_root(port)) { + port = to_cxl_port(port->dev.parent); + if (port->depth == 1) + return port; + } + + BUG(); + return NULL; +} + +static struct cxl_port *get_root_decoder(const struct cxl_memdev *endpoint) +{ + struct cxl_port *hostbridge = get_hostbridge(endpoint); + + if (hostbridge) + return to_cxl_port(hostbridge->dev.parent); + + return NULL; +} + +/** + * sanitize_region() - Check is region is reasonably configured + * @cxlr: The region to check + * + * Determination as to whether or not a region can possibly be configured is + * described in CXL Memory Device SW Guide. In order to implement the algorithms + * described there, certain more basic configuration parameters must first need + * to be validated. That is accomplished by this function. + * + * Returns 0 if the region is reasonably configured, else returns a negative + * error code. + */ +static int sanitize_region(const struct cxl_region *cxlr) +{ + const int ig = region_granularity(cxlr); + const int iw = region_ways(cxlr); + int i; + + if (dev_WARN_ONCE(&cxlr->dev, !is_cxl_region_configured(cxlr), + "unconfigured regions can't be probed (race?)\n")) { + return -ENXIO; + } + + /* + * Interleave attributes should be caught by later math, but it's + * easiest to find those issues here, now. + */ + if (!cxl_is_interleave_ways_valid(iw)) { + dev_dbg(&cxlr->dev, "Invalid number of ways\n"); + return -ENXIO; + } + + if (!cxl_is_interleave_granularity_valid(ig)) { + dev_dbg(&cxlr->dev, "Invalid interleave granularity\n"); + return -ENXIO; + } + + if (cxlr->config.size % (SZ_256M * iw)) { + dev_dbg(&cxlr->dev, "Invalid size. Must be multiple of %uM\n", + 256 * iw); + return -ENXIO; + } + + for (i = 0; i < iw; i++) { + if (!cxlr->config.targets[i]) { + dev_dbg(&cxlr->dev, "Missing memory device target%u", + i); + return -ENXIO; + } + if (!cxlr->config.targets[i]->dev.driver) { + dev_dbg(&cxlr->dev, "%s isn't CXL.mem capable\n", + dev_name(&cxlr->config.targets[i]->dev)); + return -ENODEV; + } + } + + return 0; +} + +/** + * allocate_address_space() - Gets address space for the region. + * @cxlr: The region that will consume the address space + */ +static int allocate_address_space(struct cxl_region *cxlr) +{ + /* TODO */ + return 0; +} + +/** + * find_cdat_dsmas() - Find a valid DSMAS for the region + * @cxlr: The region + */ +static bool find_cdat_dsmas(const struct cxl_region *cxlr) +{ + return true; +} + +/** + * qtg_match() - Does this root decoder have desirable QTG for the endpoint + * @rootd: The root decoder for the region + * @endpoint: Endpoint whose QTG is being compared + * + * Prior to calling this function, the caller should verify that all endpoints + * in the region have the same QTG ID. + * + * Returns true if the QTG ID of the root decoder matches the endpoint + */ +static bool qtg_match(const struct cxl_decoder *rootd, + const struct cxl_memdev *endpoint) +{ + /* TODO: */ + return true; +} + +/** + * region_xhb_config_valid() - determine cross host bridge validity + * @cxlr: The region being programmed + * @rootd: The root decoder to check against + * + * The algorithm is outlined in 2.13.14 "Verify XHB configuration sequence" of + * the CXL Memory Device SW Guide (Rev1p0). + * + * Returns true if the configuration is valid. + */ +static bool region_xhb_config_valid(const struct cxl_region *cxlr, + const struct cxl_decoder *rootd) +{ + /* TODO: */ + return true; +} + +/** + * region_hb_rp_config_valid() - determine root port ordering is correct + * @cxlr: Region to validate + * @rootd: root decoder for this @cxlr + * + * The algorithm is outlined in 2.13.15 "Verify HB root port configuration + * sequence" of the CXL Memory Device SW Guide (Rev1p0). + * + * Returns true if the configuration is valid. + */ +static bool region_hb_rp_config_valid(const struct cxl_region *cxlr, + const struct cxl_decoder *rootd) +{ + /* TODO: */ + return true; +} + +/** + * rootd_contains() - determine if this region can exist in the root decoder + * @rootd: root decoder that potentially decodes to this region + * @cxlr: region to be routed by the @rootd + */ +static bool rootd_contains(const struct cxl_region *cxlr, + const struct cxl_decoder *rootd) +{ + /* TODO: */ + return true; +} + +static bool rootd_valid(const struct cxl_region *cxlr, + const struct cxl_decoder *rootd) +{ + const struct cxl_memdev *endpoint = cxlr->config.targets[0]; + + if (!qtg_match(rootd, endpoint)) + return false; + + if (!cxl_is_pmem_t3(rootd->flags)) + return false; + + if (!region_xhb_config_valid(cxlr, rootd)) + return false; + + if (!region_hb_rp_config_valid(cxlr, rootd)) + return false; + + if (!rootd_contains(cxlr, rootd)) + return false; + + return true; +} + +struct rootd_context { + const struct cxl_region *cxlr; + struct cxl_port *hbs[CXL_DECODER_MAX_INTERLEAVE]; + int count; +}; + +static int rootd_match(struct device *dev, void *data) +{ + struct rootd_context *ctx = (struct rootd_context *)data; + const struct cxl_region *cxlr = ctx->cxlr; + + if (!is_root_decoder(dev)) + return 0; + + return !!rootd_valid(cxlr, to_cxl_decoder(dev)); +} + +/* + * This is a roughly equivalent implementation to "Figure 45 - High-level + * sequence: Finding CFMWS for region" from the CXL Memory Device SW Guide + * Rev1p0. + */ +static struct cxl_decoder *find_rootd(const struct cxl_region *cxlr, + const struct cxl_port *root) +{ + struct rootd_context ctx; + struct device *ret; + + ctx.cxlr = cxlr; + + ret = device_find_child((struct device *)&root->dev, &ctx, rootd_match); + if (ret) + return to_cxl_decoder(ret); + + return NULL; +} + +static int collect_ep_decoders(const struct cxl_region *cxlr) +{ + /* TODO: */ + return 0; +} + +static int bind_region(const struct cxl_region *cxlr) +{ + /* TODO: */ + return 0; +} + +static int cxl_region_probe(struct device *dev) +{ + struct cxl_region *cxlr = to_cxl_region(dev); + struct cxl_port *root_port; + struct cxl_decoder *rootd, *ours; + int ret; + + device_lock_assert(&cxlr->dev); + + if (cxlr->active) + return 0; + + if (uuid_is_null(&cxlr->config.uuid)) + uuid_gen(&cxlr->config.uuid); + + /* TODO: What about volatile, and LSA generated regions? */ + + ret = sanitize_region(cxlr); + if (ret) + return ret; + + ret = allocate_address_space(cxlr); + if (ret) + return ret; + + if (!find_cdat_dsmas(cxlr)) + return -ENXIO; + + rootd = rootd_from_region(cxlr); + if (!rootd) { + dev_err(dev, "Couldn't find root decoder\n"); + return -ENXIO; + } + + if (!rootd_valid(cxlr, rootd)) { + dev_err(dev, "Picked invalid rootd\n"); + return -ENXIO; + } + + root_port = get_root_decoder(cxlr->config.targets[0]); + ours = find_rootd(cxlr, root_port); + if (ours != rootd) + dev_dbg(dev, "Picked different rootd %s %s\n", + dev_name(&rootd->dev), dev_name(&ours->dev)); + if (ours) + put_device(&ours->dev); + + ret = collect_ep_decoders(cxlr); + if (ret) + return ret; + + ret = bind_region(cxlr); + if (!ret) { + cxlr->active = true; + dev_info(dev, "Bound"); + } + + return ret; +} + +static struct cxl_driver cxl_region_driver = { + .name = "cxl_region", + .probe = cxl_region_probe, + .id = CXL_DEVICE_REGION, +}; +module_cxl_driver(cxl_region_driver); + +MODULE_LICENSE("GPL v2"); +MODULE_IMPORT_NS(CXL); +MODULE_ALIAS_CXL(CXL_DEVICE_REGION); diff --git a/drivers/cxl/region.h b/drivers/cxl/region.h index eb1249e3c1d4..00a6dc729c26 100644 --- a/drivers/cxl/region.h +++ b/drivers/cxl/region.h @@ -13,6 +13,7 @@ * @id: This regions id. Id is globally unique across all regions. * @list: Node in decoder's region list. * @res: Resource this region carves out of the platform decode range. + * @active: If the region has been activated. * @config: HDM decoder program config * @config.size: Size of the region determined from LSA or userspace. * @config.uuid: The UUID for this region. @@ -25,6 +26,7 @@ struct cxl_region { int id; struct list_head list; struct resource *res; + bool active; struct { u64 size; @@ -35,4 +37,6 @@ struct cxl_region { } config; }; +bool is_cxl_region_configured(const struct cxl_region *cxlr); + #endif