From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To: "Bjorn Andersson" <andersson@kernel.org>,
"Konrad Dybcio" <konrad.dybcio@linaro.org>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Rob Herring" <robh@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-kernel@vger.kernel.org,
Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Subject: [PATCH] PCI: qcom: Implement shutdown() callback to properly reset the endpoint devices
Date: Wed, 13 Mar 2024 17:39:22 +0530 [thread overview]
Message-ID: <20240313-pci-qcom-shutdown-v1-1-fb1515334bfa@linaro.org> (raw)
PCIe host controller drivers are supposed to properly reset the endpoint
devices during host shutdown/reboot. Currently, Qcom driver doesn't do
anything during host shutdown/reboot, resulting in both PERST# and refclk
getting disabled at the same time. This prevents the endpoint device
firmware to properly reset the state machine. Because, if the refclk is
cutoff immediately along with PERST#, access to device specific registers
within the endpoint will result in a firmware crash.
To address this issue, let's call qcom_pcie_host_deinit() inside the
shutdown callback, that asserts PERST# and then cuts off the refclk with a
delay of 1ms, thus allowing the endpoint device firmware to properly
cleanup the state machine.
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
drivers/pci/controller/dwc/pcie-qcom.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 2ce2a3bd932b..41434bc4761a 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -1618,6 +1618,13 @@ static int qcom_pcie_resume_noirq(struct device *dev)
return 0;
}
+static void qcom_pcie_shutdown(struct platform_device *pdev)
+{
+ struct qcom_pcie *pcie = platform_get_drvdata(pdev);
+
+ qcom_pcie_host_deinit(&pcie->pci->pp);
+}
+
static const struct of_device_id qcom_pcie_match[] = {
{ .compatible = "qcom,pcie-apq8064", .data = &cfg_2_1_0 },
{ .compatible = "qcom,pcie-apq8084", .data = &cfg_1_0_0 },
@@ -1670,5 +1677,6 @@ static struct platform_driver qcom_pcie_driver = {
.pm = &qcom_pcie_pm_ops,
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
},
+ .shutdown = qcom_pcie_shutdown,
};
builtin_platform_driver(qcom_pcie_driver);
---
base-commit: 51459eb30f88651d3688b9e95fed0f97767ececb
change-id: 20240313-pci-qcom-shutdown-d86298186560
Best regards,
--
Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
next reply other threads:[~2024-03-13 12:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-13 12:09 Manivannan Sadhasivam [this message]
2024-03-13 14:36 ` [PATCH] PCI: qcom: Implement shutdown() callback to properly reset the endpoint devices Bjorn Helgaas
2024-03-13 15:02 ` Manivannan Sadhasivam
2024-03-13 19:16 ` Bjorn Helgaas
2024-03-14 5:35 ` Manivannan Sadhasivam
2024-03-14 6:25 ` Manivannan Sadhasivam
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