6.11-stable review patch. If anyone has any objections, please let me know.
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From: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org
[ Upstream commit d3745e3ae6c0eec517d431be926742b6e8b9b64a ]
qcom_pcie_enable_resources() is called by qcom_pcie_ep_probe() and it enables the controller resources like clocks, regulator, PHY. On one of the new unreleased Qcom SoC, PHY enablement depends on the active refclk. And on all of the supported Qcom endpoint SoCs, refclk comes from the host (RC). So calling qcom_pcie_enable_resources() without refclk causes the NoC (Network On Chip) error in the endpoint SoC and in turn results in a whole SoC crash and rebooting into EDL (Emergency Download) mode which is an unrecoverable state.
But qcom_pcie_enable_resources() is already called by qcom_pcie_perst_deassert() when PERST# is deasserted, and refclk is available at that time.
Hence, remove the unnecessary call to qcom_pcie_enable_resources() from qcom_pcie_ep_probe() to prevent the above mentioned crash.
It should be noted that this commit prevents the crash only under normal working condition (booting endpoint before host), but the crash may also occur if PERST# assert happens at the wrong time. For avoiding the crash completely, it is recommended to use SRIS mode which allows the endpoint SoC to generate its own refclk. The driver is not supporting SRIS mode currently, but will be added in the future.
Fixes: 869bc5253406 ("PCI: dwc: ep: Fix DBI access failure for drivers requiring refclk from host") Link: https://lore.kernel.org/linux-pci/20240830082319.51387-1-manivannan.sadhasiv... Tested-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Signed-off-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org Signed-off-by: Krzysztof Wilczyński kwilczynski@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/controller/dwc/pcie-qcom-ep.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c index a9b263f749b6a..c8bb7cd89678f 100644 --- a/drivers/pci/controller/dwc/pcie-qcom-ep.c +++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c @@ -858,21 +858,15 @@ static int qcom_pcie_ep_probe(struct platform_device *pdev) if (ret) return ret;
- ret = qcom_pcie_enable_resources(pcie_ep); - if (ret) { - dev_err(dev, "Failed to enable resources: %d\n", ret); - return ret; - } - ret = dw_pcie_ep_init(&pcie_ep->pci.ep); if (ret) { dev_err(dev, "Failed to initialize endpoint: %d\n", ret); - goto err_disable_resources; + return ret; }
ret = qcom_pcie_ep_enable_irq_resources(pdev, pcie_ep); if (ret) - goto err_disable_resources; + goto err_ep_deinit;
name = devm_kasprintf(dev, GFP_KERNEL, "%pOFP", dev->of_node); if (!name) { @@ -889,8 +883,8 @@ static int qcom_pcie_ep_probe(struct platform_device *pdev) disable_irq(pcie_ep->global_irq); disable_irq(pcie_ep->perst_irq);
-err_disable_resources: - qcom_pcie_disable_resources(pcie_ep); +err_ep_deinit: + dw_pcie_ep_deinit(&pcie_ep->pci.ep);
return ret; }