Linux Tegra architecture development
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From: Manikanta Maddireddy <mmaddireddy@nvidia.com>
To: Jingoo Han <jingoohan1@gmail.com>,
	Manivannan Sadhasivam <mani@kernel.org>,
	Lorenzo Pieralisi <lpieralisi@kernel.org>,
	"Krzysztof Wilczynski" <kwilczynski@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>, <linux-pci@vger.kernel.org>
Cc: Rob Herring <robh@kernel.org>,
	Thierry Reding <thierry.reding@kernel.org>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Vidya Sagar <vidyas@nvidia.com>,
	Niklas Cassel <cassel@kernel.org>, <linux-kernel@vger.kernel.org>,
	<linux-tegra@vger.kernel.org>,
	Manikanta Maddireddy <mmaddireddy@nvidia.com>
Subject: [PATCH 2/3] PCI: tegra194: Avoid full Endpoint reinit on PERST#
Date: Wed, 23 Sep 2026 12:55:53 +0530	[thread overview]
Message-ID: <20260923072554.1141864-3-mmaddireddy@nvidia.com> (raw)
In-Reply-To: <20260923072554.1141864-1-mmaddireddy@nvidia.com>

Tegra194 and Tegra234 Endpoint mode receive PERST# as a fundamental
reset. Controller registers are lost across that reset, but DWC
Endpoint resources live for the controller lifetime.

Use the DWC init-or-reinit helper for Tegra PERST# deassertions so only
reset-lost registers are restored after the first initialization. Keep
the EPF deinit notification in the deassert path where refclk and core
reset are available.

Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
---
 drivers/pci/controller/dwc/pcie-tegra194.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index 513299541f18..dd3f4c30ba52 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -1914,7 +1914,6 @@ static void pex_ep_event_pex_rst_deassert(struct tegra_pcie_dw *pcie)
 
 	/* Perform cleanup that requires refclk and core reset deasserted */
 	pci_epc_deinit_notify(pcie->pci.ep.epc);
-	dw_pcie_ep_cleanup(&pcie->pci.ep);
 
 	val = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
 	val &= ~PORT_LOGIC_SPEED_CHANGE;
@@ -1958,7 +1957,7 @@ static void pex_ep_event_pex_rst_deassert(struct tegra_pcie_dw *pcie)
 	val = (upper_32_bits(ep->msi_mem_phys) & MSIX_ADDR_MATCH_HIGH_OFF_MASK);
 	dw_pcie_writel_dbi(pci, MSIX_ADDR_MATCH_HIGH_OFF, val);
 
-	ret = dw_pcie_ep_init_registers(ep);
+	ret = dw_pcie_ep_init_or_reinit_registers(ep);
 	if (ret) {
 		dev_err(dev, "Failed to complete initialization: %d\n", ret);
 		goto fail_init_complete;
-- 
2.34.1


  parent reply	other threads:[~2026-09-23  7:26 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-23  7:25 [PATCH 0/3] PCI: dwc: Avoid full EP cleanup on PERST# Manikanta Maddireddy
2026-09-23  7:25 ` [PATCH 1/3] PCI: dwc: Add Endpoint reinit helper Manikanta Maddireddy
2026-09-23  7:25 ` Manikanta Maddireddy [this message]
2026-09-23  7:25 ` [PATCH 3/3] PCI: tegra194: Notify Endpoint functions on PERST# assert Manikanta Maddireddy

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