From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from slateblue.cherry.relay.mailchannels.net (slateblue.cherry.relay.mailchannels.net [23.83.223.168]) (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 F2A2E405C4B for ; Mon, 15 Jun 2026 15:33:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=23.83.223.168 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781537614; cv=none; b=terRbsvkEpAs4etGCIuVyXKD23JPYLRAO78kOIxebcSK+rQh+ybm8nJ3g7O7gytlsqPPVEHTxVjecI8CMV5clVzerkEVwyt0Mdujx4UrizQKOW+AlAqWN12F5sZ4qXRlk1wEKAXffEBFI0uSrmuU6pPDyx+gcIcjp4uI24k1GCg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781537614; c=relaxed/simple; bh=zWCtVT1aFY3kt21xztgdp7lhnqr7XDTu2QVM8NdRqdg=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=ZNo652kh4P8PUScLDtoXHK/q8c02a0JUlnqS8gucaThr2XWwYIgDU4Exd8N+R9hOYsWiyCFaRtoDiQWLcjB8kIbv6jhNntUO7JEh077fFQalli7LdH4auqfLY/Yz8fI5r0sNw/+qIdXhDn4ZkDwGjE7ciFSTPc74YEAJ2vzEKY4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=stgolabs.net; spf=fail smtp.mailfrom=stgolabs.net; dkim=pass (2048-bit key) header.d=stgolabs.net header.i=@stgolabs.net header.b=pDajPlcQ; arc=none smtp.client-ip=23.83.223.168 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=stgolabs.net Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=stgolabs.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=stgolabs.net header.i=@stgolabs.net header.b="pDajPlcQ" X-Sender-Id: dreamhost|x-authsender|dave@stgolabs.net Received: from relay.mailchannels.net (localhost [127.0.0.1]) by relay.mailchannels.net (Postfix) with ESMTP id 2DD2494010B; Mon, 15 Jun 2026 14:55:59 +0000 (UTC) Received: from pdx1-sub0-mail-a208.dreamhost.com (100-96-8-48.trex-nlb.outbound.svc.cluster.local [100.96.8.48]) (Authenticated sender: dreamhost) by relay.mailchannels.net (Postfix) with ESMTPA id C2D1D941CF4; Mon, 15 Jun 2026 14:55:58 +0000 (UTC) X-Sender-Id: dreamhost|x-authsender|dave@stgolabs.net X-MC-Relay: Neutral X-MailChannels-SenderId: dreamhost|x-authsender|dave@stgolabs.net X-MailChannels-Auth-Id: dreamhost X-Shelf-Cooperative: 10c0921004bf34cb_1781535359104_2230568148 X-MC-Loop-Signature: 1781535359104:1887655733 X-MC-Ingress-Time: 1781535359104 Received: from pdx1-sub0-mail-a208.dreamhost.com (pop.dreamhost.com [64.90.62.162]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384) by 100.96.8.48 (trex/7.1.5); Mon, 15 Jun 2026 14:55:59 +0000 Received: from offworld.lan (unknown [138.84.34.95]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: dave@stgolabs.net) by pdx1-sub0-mail-a208.dreamhost.com (Postfix) with ESMTPSA id 4gfCqH367wz1NY; Mon, 15 Jun 2026 07:55:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=stgolabs.net; s=dreamhost; t=1781535358; bh=OhxO9FPQPpfaQewoF9XRwVD0B640IPWbiJlXt1q0aNA=; h=From:To:Cc:Subject:Date:Content-Transfer-Encoding; b=pDajPlcQ7AyWJTL/MlUShuDzUm4AgfHcWWnRe7TNZDRbDh78DSDke/Dvtdt9FE4li zm22SNqYU+ojYWcz4ozavdnVfHXOsnH8VkJ3atpggjMgmp1/Hr9Y+yaHOYt7N3W/M7 hIWFtUKo+XlLyMP97GuRc7atOrJ7HqSRpBJSYp+qlSiWAc0fBk+rVqz6CQijE1tzuo K0QKsojGDMk91IkIhf+WmGbvO9pmbcNCYiaXu4DzaaoJG6ve5p1ySV4LJ4/PXDZ7Jq tjuB2YV1i3e30Xb0kza8fGIwxlZ6XkI9HhG5x+P4NwdOFZbV/IuIjx51Hzv1QzctrB DM+NstXqAbzgQ== From: Davidlohr Bueso To: dave.jiang@intel.com, djbw@kernel.org Cc: jic23@kernel.org, benjamin.cheatham@amd.com, icheng@nvidia.com, alucerop@amd.com, alison.schofield@intel.com, gourry@gourry.net, dongjoo.seo1@samsung.com, dave@stgolabs.net, linux-cxl@vger.kernel.org Subject: [PATCH v5 1/5] cxl: Add BI register probing and port initialization Date: Mon, 15 Jun 2026 07:55:25 -0700 Message-Id: <20260615145529.13848-2-dave@stgolabs.net> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20260615145529.13848-1-dave@stgolabs.net> References: <20260615145529.13848-1-dave@stgolabs.net> Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add register probing for BI Route Table and BI Decoder capability structures in cxl_probe_component_regs(), and helpers to map them. cxl_dport_map_bi() maps the BI Decoder of a downstream port (root port or switch DSP) at dport-creation time via cxl_port_add_dport(); cxl_port_map_bi() maps a port's own BI capability during port probe when the upstream link is in 256B Flit operation -- BI Decoder for an endpoint, BI RT for a switch USP. Signed-off-by: Davidlohr Bueso --- drivers/cxl/core/regs.c | 14 ++++++++ drivers/cxl/cxl.h | 6 ++++ drivers/cxl/port.c | 71 +++++++++++++++++++++++++++++++++++++++++ include/cxl/cxl.h | 6 ++++ 4 files changed, 97 insertions(+) diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c index 93710cf4f0a6..a6caa793e7a4 100644 --- a/drivers/cxl/core/regs.c +++ b/drivers/cxl/core/regs.c @@ -92,6 +92,18 @@ void cxl_probe_component_regs(struct device *dev, void __iomem *base, length = CXL_RAS_CAPABILITY_LENGTH; rmap = &map->ras; break; + case CXL_CM_CAP_CAP_ID_BI_RT: + dev_dbg(dev, "found BI RT capability (0x%x)\n", + offset); + length = CXL_BI_RT_CAPABILITY_LENGTH; + rmap = &map->bi_rt; + break; + case CXL_CM_CAP_CAP_ID_BI_DECODER: + dev_dbg(dev, "found BI Decoder capability (0x%x)\n", + offset); + length = CXL_BI_DECODER_CAPABILITY_LENGTH; + rmap = &map->bi_decoder; + break; default: dev_dbg(dev, "Unknown CM cap ID: %d (0x%x)\n", cap_id, offset); @@ -211,6 +223,8 @@ int cxl_map_component_regs(const struct cxl_register_map *map, } mapinfo[] = { { &map->component_map.hdm_decoder, ®s->hdm_decoder }, { &map->component_map.ras, ®s->ras }, + { &map->component_map.bi_rt, ®s->bi_rt }, + { &map->component_map.bi_decoder, ®s->bi_decoder }, }; int i; diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index 1297594beaec..760f51b43891 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -42,6 +42,12 @@ extern const struct nvdimm_security_ops *cxl_security_ops; #define CXL_CM_CAP_CAP_ID_RAS 0x2 #define CXL_CM_CAP_CAP_ID_HDM 0x5 #define CXL_CM_CAP_CAP_HDM_VERSION 1 +#define CXL_CM_CAP_CAP_ID_BI_RT 0xB +#define CXL_CM_CAP_CAP_ID_BI_DECODER 0xC + +/* CXL 4.0 8.2.4.26 / 8.2.4.27 BI Capability Structures */ +#define CXL_BI_RT_CAPABILITY_LENGTH 0xC +#define CXL_BI_DECODER_CAPABILITY_LENGTH 0xC /* HDM decoders CXL 2.0 8.2.5.12 CXL HDM Decoder Capability Structure */ #define CXL_HDM_DECODER_CAP_OFFSET 0x0 diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c index ada51948d52f..ca8d8c14b787 100644 --- a/drivers/cxl/port.c +++ b/drivers/cxl/port.c @@ -58,6 +58,62 @@ static int discover_region(struct device *dev, void *unused) return 0; } +static void cxl_dport_map_bi(struct cxl_dport *dport) +{ + struct cxl_register_map *map = &dport->reg_map; + struct device *dev = dport->dport_dev; + + if (!map->component_map.bi_decoder.valid) { + dev_dbg(dev, "BI Decoder registers not found\n"); + return; + } + + if (cxl_map_component_regs(map, &dport->regs.component, + BIT(CXL_CM_CAP_CAP_ID_BI_DECODER))) + dev_dbg(dev, "Failed to map BI Decoder capability\n"); +} + +static void cxl_port_map_bi(struct cxl_port *port) +{ + struct cxl_register_map *map = &port->reg_map; + struct cxl_dport *parent_dport = port->parent_dport; + struct device *udev; + int cap_id; + + /* no upstream BI registers above host bridges or the cxl_root */ + if (!parent_dport || is_cxl_root(parent_dport->port)) + return; + + udev = is_cxl_endpoint(port) ? + port->uport_dev->parent : port->uport_dev; + if (!dev_is_pci(udev)) + return; + + /* BI requires 256B Flit on the upstream link */ + if (!cxl_pci_flit_256(to_pci_dev(udev))) + return; + + /* map this port's own BI capability */ + if (is_cxl_endpoint(port)) { + if (!map->component_map.bi_decoder.valid) { + dev_dbg(&port->dev, "BI Decoder registers not found\n"); + return; + } + cap_id = CXL_CM_CAP_CAP_ID_BI_DECODER; + } else { + if (!map->component_map.bi_rt.valid) { + dev_dbg(&port->dev, "BI RT registers not found\n"); + return; + } + cap_id = CXL_CM_CAP_CAP_ID_BI_RT; + } + + map->host = &port->dev; + if (cxl_map_component_regs(map, &port->regs, BIT(cap_id))) + dev_dbg(&port->dev, "Failed to map BI capability 0x%x\n", + cap_id); +} + static int cxl_switch_port_probe(struct cxl_port *port) { /* Reset nr_dports for rebind of driver */ @@ -128,6 +184,8 @@ static int cxl_endpoint_port_probe(struct cxl_port *port) read_cdat_data(port); cxl_endpoint_parse_cdat(port); + cxl_port_map_bi(port); + get_device(&cxlmd->dev); rc = devm_add_action_or_reset(&port->dev, schedule_detach, cxlmd); if (rc) @@ -252,6 +310,8 @@ static struct cxl_dport *cxl_port_add_dport(struct cxl_port *port, * on failure, or the device does not implement RAS registers. */ devm_cxl_port_ras_setup(port); + + cxl_port_map_bi(port); } dport = devm_cxl_add_dport_by_dev(port, dport_dev); @@ -261,6 +321,17 @@ static struct cxl_dport *cxl_port_add_dport(struct cxl_port *port, /* This group was only needed for early exit above */ devres_remove_group(&port->dev, no_free_ptr(port_dr_group)); + if (dev_is_pci(dport_dev)) { + switch (pci_pcie_type(to_pci_dev(dport_dev))) { + case PCI_EXP_TYPE_ROOT_PORT: + case PCI_EXP_TYPE_DOWNSTREAM: + cxl_dport_map_bi(dport); + break; + default: + break; + } + } + cxl_switch_parse_cdat(dport); /* New dport added, update the decoder targets */ diff --git a/include/cxl/cxl.h b/include/cxl/cxl.h index fa7269154620..8ce9b4e9ca73 100644 --- a/include/cxl/cxl.h +++ b/include/cxl/cxl.h @@ -34,10 +34,14 @@ struct cxl_regs { * Common set of CXL Component register block base pointers * @hdm_decoder: CXL 2.0 8.2.5.12 CXL HDM Decoder Capability Structure * @ras: CXL 2.0 8.2.5.9 CXL RAS Capability Structure + * @bi_rt: CXL 4.0 8.2.4.26 CXL BI Route Table Capability Structure + * @bi_decoder: CXL 4.0 8.2.4.27 CXL BI Decoder Capability Structure */ struct_group_tagged(cxl_component_regs, component, void __iomem *hdm_decoder; void __iomem *ras; + void __iomem *bi_rt; + void __iomem *bi_decoder; ); /* * Common set of CXL Device register block base pointers @@ -80,6 +84,8 @@ struct cxl_reg_map { struct cxl_component_reg_map { struct cxl_reg_map hdm_decoder; struct cxl_reg_map ras; + struct cxl_reg_map bi_rt; + struct cxl_reg_map bi_decoder; }; struct cxl_device_reg_map { -- 2.39.5