From patchwork Thu Sep 19 08:13:44 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shivasharan Srikanteshwara X-Patchwork-Id: 13807495 X-Patchwork-Delegate: bhelgaas@google.com Received: from mail-pl1-f176.google.com (mail-pl1-f176.google.com [209.85.214.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5F1D1198A30 for ; Thu, 19 Sep 2024 08:25:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.176 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726734343; cv=none; b=OZbQJCUpO1kzuXeiLGrulWrcHO023NChsFxRmL+8ZV5vLM9faqySr7FyMadTYGv0ZnQ1qKMHShjNH9YXAXL/NjYJS/a5iEw6jFk8QsQf/t9Kth7mzCdsae1tOalb0r+wsAqapvR567tkFcI8EnwNgX8oVgfkhBk40y+kdKj9PFw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726734343; c=relaxed/simple; bh=8NqLkMy3Zx6bnWeNPtd3QcNpt2w1EU41lxesU7fl/oE=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References; b=BtHUtKjODqS395tLa7A7dDVpUYpTDgGEAWWck6WMj67F8HZztDG7q2Ql6yTZI1g+qcU+jv7Oqpla1xhF7z1jJprCAw2F7EESx1zRwfmj53Ev+4p5Ug4PrCGMuPV2O6kFQftW61PZFBROum/ZID26XI5Zj8BdBvKigYc4BCFJPSk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=broadcom.com; spf=fail smtp.mailfrom=broadcom.com; dkim=pass (1024-bit key) header.d=broadcom.com header.i=@broadcom.com header.b=CmHtYYP6; arc=none smtp.client-ip=209.85.214.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=broadcom.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=broadcom.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=broadcom.com header.i=@broadcom.com header.b="CmHtYYP6" Received: by mail-pl1-f176.google.com with SMTP id d9443c01a7336-20573eb852aso11427955ad.1 for ; Thu, 19 Sep 2024 01:25:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; t=1726734341; x=1727339141; darn=vger.kernel.org; h=references:in-reply-to:message-id:date:subject:cc:to:from:from:to :cc:subject:date:message-id:reply-to; bh=HmqZt8e3zro76L+L3lI/fpw4YEZYvty94868lL6i/x0=; b=CmHtYYP6D1Pc0srB4ZVKie96F6yiKRnAOdibKwZAZFSt3v+AiW4EbuVH3UpfO40xyc jE7fqiXfRwp4RUEYNXDIQ5dh26d80e4zKf5p2j+Hj/udHtrA6zglre+0l0L0B6vLw6fb ozjhngH1773zjME1YyuX/NVOa+4aXkQVvtuGI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1726734341; x=1727339141; h=references:in-reply-to:message-id:date:subject:cc:to:from :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=HmqZt8e3zro76L+L3lI/fpw4YEZYvty94868lL6i/x0=; b=f8GymW6mf35v2Izr18LUVxYdRjKgnb40t/nrFI6pwTF3elhCXfCpoM4vPUhC+cRyuS yTw7Ii3dkFQkwV9uUTUl3pJ7DM4WQSfX+t7WgaVi9kiGLoycLoQ/JYm/8H4+MgElsEAG BqyyJXd1lMvFZprMSzQxDhHOB3qX5eJkFyR96zs1iPbn6wug9n6RBiJkSIfYexZjBmvN y3YpvsCzifUYlfdlVLsl60sWKRcTIIz4CplC/h3oLVM+Hg3W7T8m30//BC+2i2CkAxw9 umLvdR01Uy088XHmeck8uztwen5UTQUm60PtwBKP5TIAinuFCVWSjxRKmDQk5y3rEXW/ ExYg== X-Gm-Message-State: AOJu0Yw/78+n9oLHXUAYyVsjpnz7zfeLYavdsJVZ5JMJX3DwbaIE4K8F Bsf50/2tmY9zFuSLEqq0tkSsBV9XdNn1vA1c8+zGuetN5TWnRtKr5KR/UP8LKUlHgIT2KFSNnnb tdBJ8ghC7trV5f+Rvbk2pFDMy2s24bpBiEztvxiBwoENQKCQY1BkCfTf0cyrJ6tlDsmVj3MVUQ4 6UZyuh22labbgt1IRGa8hOCb4AkOWuOUg7ylO1gAPh1jR48Vq8046q4Gh3vbthi3I= X-Google-Smtp-Source: AGHT+IGIoR7DQTByHj/l4Zf/Tfkw0Ev3y9F9w0HlqKuds5yDKg55HUfdksZ5EucrAa8WOWGaXEVCsw== X-Received: by 2002:a17:902:f706:b0:205:8763:6c2d with SMTP id d9443c01a7336-208cb8b392emr43227385ad.9.1726734341144; Thu, 19 Sep 2024 01:25:41 -0700 (PDT) Received: from dhcp-135-24-192-142.dhcp.broadcom.net ([192.19.234.250]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-20794735810sm75228425ad.278.2024.09.19.01.25.38 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 19 Sep 2024 01:25:40 -0700 (PDT) From: Shivasharan S To: linux-pci@vger.kernel.org, bhelgaas@google.com, manivannan.sadhasivam@linaro.org, logang@deltatee.com Cc: linux-kernel@vger.kernel.org, sumanesh.samanta@broadcom.com, sathya.prakash@broadcom.com, sjeaugey@nvidia.com, Shivasharan S Subject: [PATCH 2/2 v2] PCI/P2PDMA: Modify p2p_dma_distance to detect P2P links Date: Thu, 19 Sep 2024 01:13:44 -0700 Message-Id: <1726733624-2142-3-git-send-email-shivasharan.srikanteshwara@broadcom.com> X-Mailer: git-send-email 2.4.3 In-Reply-To: <1726733624-2142-1-git-send-email-shivasharan.srikanteshwara@broadcom.com> References: <1726733624-2142-1-git-send-email-shivasharan.srikanteshwara@broadcom.com> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Update the p2p_dma_distance() to determine inter-switch P2P links existing between two switches and use this to calculate the DMA distance between two devices. Signed-off-by: Shivasharan S --- drivers/pci/p2pdma.c | 17 ++++++++++++++++- drivers/pci/pcie/portdrv.c | 34 ++++++++++++++++++++++++++++++++++ drivers/pci/pcie/portdrv.h | 2 ++ 3 files changed, 52 insertions(+), 1 deletion(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 4f47a13cb500..eed3b69e7293 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -21,6 +21,8 @@ #include #include +extern bool pcie_port_is_p2p_link_available(struct pci_dev *a, struct pci_dev *b); + struct pci_p2pdma { struct gen_pool *pool; bool p2pmem_published; @@ -576,7 +578,7 @@ calc_map_type_and_dist(struct pci_dev *provider, struct pci_dev *client, int *dist, bool verbose) { enum pci_p2pdma_map_type map_type = PCI_P2PDMA_MAP_THRU_HOST_BRIDGE; - struct pci_dev *a = provider, *b = client, *bb; + struct pci_dev *a = provider, *b = client, *bb, *b_p2p_link = NULL; bool acs_redirects = false; struct pci_p2pdma *p2pdma; struct seq_buf acs_list; @@ -606,6 +608,16 @@ calc_map_type_and_dist(struct pci_dev *provider, struct pci_dev *client, if (a == bb) goto check_b_path_acs; + /* + * If both upstream bridges have Inter switch P2P link + * available, P2P DMA distance can account for optimized + * path. + */ + if (pcie_port_is_p2p_link_available(a, bb)) { + b_p2p_link = bb; + goto check_b_path_acs; + } + bb = pci_upstream_bridge(bb); dist_b++; } @@ -629,6 +641,9 @@ calc_map_type_and_dist(struct pci_dev *provider, struct pci_dev *client, acs_cnt++; } + if (bb == b_p2p_link) + break; + bb = pci_upstream_bridge(bb); } diff --git a/drivers/pci/pcie/portdrv.c b/drivers/pci/pcie/portdrv.c index c940b4b242fd..2fe1598fc684 100644 --- a/drivers/pci/pcie/portdrv.c +++ b/drivers/pci/pcie/portdrv.c @@ -104,6 +104,40 @@ static bool pcie_port_is_p2p_supported(struct pci_dev *dev) return false; } +/** + * pcie_port_is_p2p_link_available: Determine if a P2P link is available + * between the two upstream bridges. The serial number of the two devices + * will be compared and if they are same then it is considered that the P2P + * link is available. + * + * Return value: true if inter switch P2P is available, return false otherwise. + */ +bool pcie_port_is_p2p_link_available(struct pci_dev *a, struct pci_dev *b) +{ + u64 dsn_a, dsn_b; + + /* + * Check if the devices support Inter switch P2P. + */ + if (!pcie_port_is_p2p_supported(a) || + !pcie_port_is_p2p_supported(b)) + return false; + + dsn_a = pci_get_dsn(a); + if (!dsn_a) + return false; + + dsn_b = pci_get_dsn(b); + if (!dsn_b) + return false; + + if (dsn_a == dsn_b) + return true; + + return false; +} +EXPORT_SYMBOL_GPL(pcie_port_is_p2p_link_available); + /* * Traverse list of all PCI bridges and find devices that support Inter switch P2P * and have the same serial number to create report the BDF over sysfs. diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h index 1be06cb45665..b341aad6eb49 100644 --- a/drivers/pci/pcie/portdrv.h +++ b/drivers/pci/pcie/portdrv.h @@ -130,5 +130,7 @@ static inline bool pcie_pme_no_msi(void) { return false; } static inline void pcie_pme_interrupt_enable(struct pci_dev *dev, bool en) {} #endif /* !CONFIG_PCIE_PME */ +bool pcie_port_is_p2p_link_available(struct pci_dev *a, struct pci_dev *b); + struct device *pcie_port_find_device(struct pci_dev *dev, u32 service); #endif /* _PORTDRV_H_ */