From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 829E4C63699 for ; Fri, 13 Nov 2020 18:17:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 43D8B206F9 for ; Fri, 13 Nov 2020 18:17:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="uuOXqaI5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726348AbgKMSRf (ORCPT ); Fri, 13 Nov 2020 13:17:35 -0500 Received: from mail.kernel.org ([198.145.29.99]:57984 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726081AbgKMSRf (ORCPT ); Fri, 13 Nov 2020 13:17:35 -0500 Received: from localhost (230.sub-72-107-127.myvzw.com [72.107.127.230]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C539B2074B; Fri, 13 Nov 2020 18:17:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605291454; bh=FwNxJBVYLmY0I7UT2gwMeGvnRBxnjf3Vj6esUleM+bE=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=uuOXqaI5HlGmp9yRBHllON2jZ2TxrmP0ubmXp7A8iJCuQeYBofMwtXDBz/TeAi4WX FDYMLLQaenDuEVLjGYoK55MMKKZ/EoSHDpNYsdtUQnXBrkhiFphK3XXn4Ycp3QGUTj a+NlQl2PSILp/e0v6nq82qhLq2V9SGqFiQI5gz+U= Date: Fri, 13 Nov 2020 12:17:32 -0600 From: Bjorn Helgaas To: Ben Widawsky Cc: linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, Dan Williams , Ira Weiny , Vishal Verma , "Kelley, Sean V" , Bjorn Helgaas , "Rafael J . Wysocki" Subject: Re: [RFC PATCH 4/9] cxl/mem: Map memory device registers Message-ID: <20201113181732.GA1121121@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201111054356.793390-5-ben.widawsky@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Tue, Nov 10, 2020 at 09:43:51PM -0800, Ben Widawsky wrote: > All the necessary bits are initialized in order to find and map the > register space for CXL Memory Devices. This is accomplished by using the > Register Locator DVSEC (CXL 2.0 - 8.1.9.1) to determine which PCI BAR to > use, and how much of an offset from that BAR should be added. "Initialize the necessary bits ..." to use the usual imperative sentence structure, as you did in the subject. > If the memory device registers are found and mapped a new internal data > structure tracking device state is allocated. "Allocate device state if we find device registers" or similar. > Signed-off-by: Ben Widawsky > --- > drivers/cxl/mem.c | 68 +++++++++++++++++++++++++++++++++++++++++++---- > drivers/cxl/pci.h | 6 +++++ > 2 files changed, 69 insertions(+), 5 deletions(-) > > diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c > index aa7d881fa47b..8d9b9ab6c5ea 100644 > --- a/drivers/cxl/mem.c > +++ b/drivers/cxl/mem.c > @@ -7,9 +7,49 @@ > #include "pci.h" > > struct cxl_mem { > + struct pci_dev *pdev; > void __iomem *regs; > }; > > +static struct cxl_mem *cxl_mem_create(struct pci_dev *pdev, u32 reg_lo, u32 reg_hi) > +{ > + struct device *dev = &pdev->dev; > + struct cxl_mem *cxlm; > + void __iomem *regs; > + u64 offset; > + u8 bar; > + int rc; > + > + offset = ((u64)reg_hi << 32) | (reg_lo & 0xffff0000); > + bar = reg_lo & 0x7; > + > + /* Basic sanity check that BAR is big enough */ > + if (pci_resource_len(pdev, bar) < offset) { > + dev_err(dev, "bar%d: %pr: too small (offset: %#llx)\n", > + bar, &pdev->resource[bar], (unsigned long long) offset); s/bar/BAR/ > + return ERR_PTR(-ENXIO); > + } > + > + rc = pcim_iomap_regions(pdev, 1 << bar, pci_name(pdev)); > + if (rc != 0) { > + dev_err(dev, "failed to map registers\n"); > + return ERR_PTR(-ENXIO); > + } > + > + cxlm = devm_kzalloc(&pdev->dev, sizeof(*cxlm), GFP_KERNEL); > + if (!cxlm) { > + dev_err(dev, "No memory available\n"); > + return ERR_PTR(-ENOMEM); > + } > + > + regs = pcim_iomap_table(pdev)[bar]; > + cxlm->pdev = pdev; > + cxlm->regs = regs + offset; > + > + dev_dbg(dev, "Mapped CXL Memory Device resource\n"); > + return cxlm; > +} > + > static int cxl_mem_dvsec(struct pci_dev *pdev, int dvsec) > { > int pos; > @@ -34,9 +74,9 @@ static int cxl_mem_dvsec(struct pci_dev *pdev, int dvsec) > > static int cxl_mem_probe(struct pci_dev *pdev, const struct pci_device_id *id) > { > + struct cxl_mem *cxlm = ERR_PTR(-ENXIO); > struct device *dev = &pdev->dev; > - struct cxl_mem *cxlm; The order was better before ("dev", then "clxm"). Oh, I suppose this is a "reverse Christmas tree" thing. > - int rc, regloc; > + int rc, regloc, i; > > rc = cxl_bus_prepared(pdev); > if (rc != 0) { > @@ -44,15 +84,33 @@ static int cxl_mem_probe(struct pci_dev *pdev, const struct pci_device_id *id) > return rc; > } > > + rc = pcim_enable_device(pdev); > + if (rc) > + return rc; > + > regloc = cxl_mem_dvsec(pdev, PCI_DVSEC_ID_CXL_REGLOC); > if (!regloc) { > dev_err(dev, "register location dvsec not found\n"); > return -ENXIO; > } > + regloc += 0xc; /* Skip DVSEC + reserved fields */ > + > + for (i = regloc; i < regloc + 0x24; i += 8) { > + u32 reg_lo, reg_hi; > + > + pci_read_config_dword(pdev, i, ®_lo); > + pci_read_config_dword(pdev, i + 4, ®_hi); > + > + if (CXL_REGLOG_IS_MEMDEV(reg_lo)) { > + cxlm = cxl_mem_create(pdev, reg_lo, reg_hi); > + break; > + } > + } > + > + if (IS_ERR(cxlm)) > + return -ENXIO; I think this would be easier to read if cxl_mem_create() returned NULL on failure (it prints error messages and we throw away -ENXIO/-ENOMEM distinction here anyway) so you could do: struct cxl_mem *cxlm = NULL; for (...) { if (...) { cxlm = cxl_mem_create(pdev, reg_lo, reg_hi); break; } } if (!cxlm) return -ENXIO; /* -ENODEV might be more natural? */ > - cxlm = devm_kzalloc(dev, sizeof(*cxlm), GFP_KERNEL); > - if (!cxlm) > - return -ENOMEM; > + pci_set_drvdata(pdev, cxlm); > > return 0; > } > diff --git a/drivers/cxl/pci.h b/drivers/cxl/pci.h > index beb03921e6da..be87f62e9132 100644 > --- a/drivers/cxl/pci.h > +++ b/drivers/cxl/pci.h > @@ -12,4 +12,10 @@ > #define PCI_DVSEC_ID_CXL 0x0 > #define PCI_DVSEC_ID_CXL_REGLOC 0x8 > > +#define CXL_REGLOG_RBI_EMPTY 0 > +#define CXL_REGLOG_RBI_COMPONENT 1 > +#define CXL_REGLOG_RBI_VIRT 2 > +#define CXL_REGLOG_RBI_MEMDEV 3 Maybe line these values up. > +#define CXL_REGLOG_IS_MEMDEV(x) ((((x) >> 8) & 0xff) == CXL_REGLOG_RBI_MEMDEV) If these are only needed in cxl/mem.c, they could go there. Do you expect code outside of drivers/cxl to need these? > #endif /* __CXL_PCI_H__ */ > -- > 2.29.2 >