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
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <20250325071832.21229-1-mike.looijmans@topic.nl>
Date: Tue, 25 Mar 2025 08:18:25 +0100
From: Mike Looijmans <mike.looijmans@...ic.nl>
To: linux-pci@...r.kernel.org,
	devicetree@...r.kernel.org
CC: Mike Looijmans <mike.looijmans@...ic.nl>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Krzysztof WilczyƄski <kw@...ux.com>,
	Lorenzo Pieralisi <lpieralisi@...nel.org>,
	Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
	Michal Simek <michal.simek@....com>,
	Rob Herring <robh@...nel.org>,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2 1/3] pcie-xilinx: Wait for link-up status during initialization

When the driver loads, the transceiver may still be in the state of
setting up a link. Wait for that to complete before continuing. This
fixes that the PCIe core does not work when loading the PL bitstream
from userspace. There's only milliseconds between the FPGA boot and the
core initializing in that case, and the link won't be up yet. The design
only worked when the FPGA was programmed in the bootloader, as that will
give the system hundreds of milliseconds to boot.

As the PCIe spec allows up to 100 ms time to establish a link, we'll
allow up to 200ms before giving up.

Signed-off-by: Mike Looijmans <mike.looijmans@...ic.nl>
---

Changes in v2:
Split into "reset GPIO" and "wait for link" patches
Add timeout explanation

 drivers/pci/controller/pcie-xilinx.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pcie-xilinx.c b/drivers/pci/controller/pcie-xilinx.c
index 0b534f73a942..2e59b91f43e0 100644
--- a/drivers/pci/controller/pcie-xilinx.c
+++ b/drivers/pci/controller/pcie-xilinx.c
@@ -15,6 +15,7 @@
 #include <linux/irqdomain.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
+#include <linux/iopoll.h>
 #include <linux/msi.h>
 #include <linux/of_address.h>
 #include <linux/of_pci.h>
@@ -126,6 +127,19 @@ static inline bool xilinx_pcie_link_up(struct xilinx_pcie *pcie)
 		XILINX_PCIE_REG_PSCR_LNKUP) ? 1 : 0;
 }
 
+static int xilinx_pci_wait_link_up(struct xilinx_pcie *pcie)
+{
+	u32 val;
+
+	/*
+	 * PCIe r6.0, sec 6.6.1 provides 100ms timeout. Since this is FPGA
+	 * fabric, we're more lenient and allow 200 ms for link training.
+	 */
+	return readl_poll_timeout(pcie->reg_base + XILINX_PCIE_REG_PSCR, val,
+			(val & XILINX_PCIE_REG_PSCR_LNKUP), 2 * USEC_PER_MSEC,
+			200 * USEC_PER_MSEC);
+}
+
 /**
  * xilinx_pcie_clear_err_interrupts - Clear Error Interrupts
  * @pcie: PCIe port information
@@ -493,7 +507,7 @@ static void xilinx_pcie_init_port(struct xilinx_pcie *pcie)
 {
 	struct device *dev = pcie->dev;
 
-	if (xilinx_pcie_link_up(pcie))
+	if (!xilinx_pci_wait_link_up(pcie))
 		dev_info(dev, "PCIe Link is UP\n");
 	else
 		dev_info(dev, "PCIe Link is DOWN\n");
-- 
2.43.0


Met vriendelijke groet / kind regards,

Mike Looijmans
System Expert


TOPIC Embedded Products B.V.
Materiaalweg 4, 5681 RJ Best
The Netherlands

T: +31 (0) 499 33 69 69
E: mike.looijmans@...ic.nl
W: www.topic.nl

Please consider the environment before printing this e-mail

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ