lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Thu, 24 Feb 2022 18:08:00 -0600 From: Bjorn Helgaas <helgaas@...nel.org> To: Pali Rohár <pali@...nel.org> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@....com>, Bjorn Helgaas <bhelgaas@...gle.com>, Rob Herring <robh+dt@...nel.org>, Thomas Petazzoni <thomas.petazzoni@...tlin.com>, Krzysztof Wilczyński <kw@...ux.com>, Marek Behún <kabel@...nel.org>, Russell King <rmk+kernel@...linux.org.uk>, linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org Subject: Re: [PATCH v4 05/12] PCI: mvebu: Correctly configure x1/x4 mode On Tue, Feb 22, 2022 at 04:50:23PM +0100, Pali Rohár wrote: > If x1/x4 mode is not set correctly then link with endpoint card is not > established. > > Use DTS property 'num-lanes' to deteriminate x1/x4 mode. I know this is already merged, but if tweaking for any other reason, s/deteriminate/determine/ > + * Set Maximum Link Width to X1 or X4 in Root Port's PCIe Link > + * Capability register. This register is defined by PCIe specification > + * as read-only but this mvebu controller has it as read-write and must > + * be set to number of SerDes PCIe lanes (1 or 4). If this register is > + * not set correctly then link with endpoint card is not established. True, everything in Link Capability is RO or HwInit, but that's for the architected access via config space. I think a device-specific mechanism like this is fair game as long as you do it before anybody can read it via config space. > + */ > + lnkcap = mvebu_readl(port, PCIE_CAP_PCIEXP + PCI_EXP_LNKCAP); > + lnkcap &= ~PCI_EXP_LNKCAP_MLW; > + lnkcap |= (port->is_x4 ? 4 : 1) << 4; > + mvebu_writel(port, lnkcap, PCIE_CAP_PCIEXP + PCI_EXP_LNKCAP);
Powered by blists - more mailing lists