From patchwork Fri Jan 28 00:27:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ben Widawsky X-Patchwork-Id: 12727591 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 5E1063FF9; Fri, 28 Jan 2022 00:27:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1643329649; x=1674865649; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=8bZ/y5CvmAUZBLyNdbWRgpD9oM1QXHWBY0H6dpPm7No=; b=g1JccmLAAaOh7vfK9nwTIC03B9cqj+4qaCtSIKqUunUUmYqprdkGslxK 9yMiCmuoNpumfw2cxSSN9eQkiTIA8ilBd1LpXe+VC/5aK5ob8napfzqXa 7wPW9gZwbk3texEnk9/zvq7g1dr5ZOWeQA2ABSrNDtyIT4LEWjwk9c7pW bXK0IUevcxsjNcr60daZw8Q0CIyfGW7lsPyR568f72EaVdBwEKS9+01VW OEjmUqFHy/YJHiD4Vs2tRHr5wWFG7KayQVZZTEarHakkjXyc6J54k6Y5n 30rCrcsifEWFCociAwIdrkeq3+rj53/84EFZ3aaiHFWDKTAFnWvzzjnBg g==; X-IronPort-AV: E=McAfee;i="6200,9189,10239"; a="226982083" X-IronPort-AV: E=Sophos;i="5.88,322,1635231600"; d="scan'208";a="226982083" 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 16:27:28 -0800 X-IronPort-AV: E=Sophos;i="5.88,322,1635231600"; d="scan'208";a="674909654" 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 16:27:28 -0800 From: Ben Widawsky To: linux-cxl@vger.kernel.org Cc: patches@lists.linux.dev, Ben Widawsky , Alison Schofield , Dan Williams , Ira Weiny , Jonathan Cameron , Vishal Verma , Bjorn Helgaas , nvdimm@lists.linux.dev, linux-pci@vger.kernel.org Subject: [PATCH v3 11/14] cxl/region: Add support for single switch level Date: Thu, 27 Jan 2022 16:27:04 -0800 Message-Id: <20220128002707.391076-12-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 CXL switches have HDM decoders just like host bridges and endpoints. Their programming works in a similar fashion. The spec does not prohibit multiple levels of switches, however, those are not implemented at this time. Signed-off-by: Ben Widawsky --- drivers/cxl/cxl.h | 5 ++++ drivers/cxl/region.c | 61 ++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 64 insertions(+), 2 deletions(-) diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index 8ace6cca0776..d70d8c85d05f 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -96,6 +96,11 @@ static inline u8 cxl_to_ig(u16 g) return ilog2(g) - 8; } +static inline int cxl_to_ways(u8 ways) +{ + return 1 << ways; +} + static inline bool cxl_is_interleave_ways_valid(int iw) { switch (iw) { diff --git a/drivers/cxl/region.c b/drivers/cxl/region.c index b8982be13bfe..f748060733dd 100644 --- a/drivers/cxl/region.c +++ b/drivers/cxl/region.c @@ -359,6 +359,23 @@ static bool has_switch(const struct cxl_region *cxlr) return false; } +static bool has_multi_switch(const struct cxl_region *cxlr) +{ + struct cxl_memdev *ep; + int i; + + for_each_cxl_endpoint(ep, cxlr, i) + if (ep->port->depth > 3) + return true; + + return false; +} + +static struct cxl_port *get_switch(struct cxl_memdev *ep) +{ + return to_cxl_port(ep->port->dev.parent); +} + static struct cxl_decoder *get_decoder(struct cxl_region *cxlr, struct cxl_port *p) { @@ -409,6 +426,8 @@ static bool region_hb_rp_config_valid(struct cxl_region *cxlr, const struct cxl_decoder *rootd, bool state_update) { + const int region_ig = cxl_to_ig(cxlr->config.interleave_granularity); + const int region_eniw = cxl_to_eniw(cxlr->config.interleave_ways); const int num_root_ports = get_num_root_ports(cxlr); struct cxl_port *hbs[CXL_DECODER_MAX_INTERLEAVE]; struct cxl_decoder *cxld, *c; @@ -416,8 +435,12 @@ static bool region_hb_rp_config_valid(struct cxl_region *cxlr, hb_count = get_unique_hostbridges(cxlr, hbs); - /* TODO: Switch support */ - if (has_switch(cxlr)) + /* TODO: support multiple levels of switches */ + if (has_multi_switch(cxlr)) + return false; + + /* TODO: x3 interleave for switches is hard. */ + if (has_switch(cxlr) && !is_power_of_2(region_ways(cxlr))) return false; /* @@ -470,8 +493,14 @@ static bool region_hb_rp_config_valid(struct cxl_region *cxlr, list_for_each_entry(rp, &hb->dports, list) { struct cxl_memdev *ep; int port_grouping = -1; + int target_ndx; for_each_cxl_endpoint_hb(ep, cxlr, hb, idx) { + struct cxl_decoder *switch_cxld; + struct cxl_dport *target; + struct cxl_port *switch_port; + bool found = false; + if (get_rp(ep) != rp) continue; @@ -499,6 +528,34 @@ static bool region_hb_rp_config_valid(struct cxl_region *cxlr, cxld->interleave_ways++; cxld->target[port_grouping] = get_rp(ep); + + /* + * At least one switch is connected here if the endpoint + * has a depth > 2 + */ + if (ep->port->depth == 2) + continue; + + /* Check the staged list to see if this + * port has already been added + */ + switch_port = get_switch(ep); + list_for_each_entry(switch_cxld, &cxlr->staged_list, region_link) { + if (to_cxl_port(switch_cxld->dev.parent) == switch_port) + found = true; + } + + if (found) { + target = cxl_find_dport_by_dev(switch_port, ep->dev.parent->parent); + switch_cxld->target[target_ndx++] = target; + continue; + } + + target_ndx = 0; + + switch_cxld = get_decoder(cxlr, switch_port); + switch_cxld->interleave_ways++; + switch_cxld->interleave_granularity = cxl_to_ways(region_ig + region_eniw); } } }