From: Manikanta Maddireddy <mmaddireddy@nvidia.com>
To: <jingoohan1@gmail.com>, <mani@kernel.org>,
<lpieralisi@kernel.org>, <kwilczynski@kernel.org>,
<bhelgaas@google.com>, <linux-pci@vger.kernel.org>
Cc: <robh@kernel.org>, <thierry.reding@kernel.org>,
<jonathanh@nvidia.com>, <vidyas@nvidia.com>, <cassel@kernel.org>,
<linux-kernel@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
<mmaddireddy@nvidia.com>
Subject: [PATCH v2 2/3] PCI: tegra194: Avoid full Endpoint reinit on PERST#
Date: Wed, 21 Oct 2026 11:49:02 +0530 [thread overview]
Message-ID: <20261021061903.1269605-3-mmaddireddy@nvidia.com> (raw)
In-Reply-To: <20261021061903.1269605-1-mmaddireddy@nvidia.com>
Tegra194 and Tegra234 lose controller register state across PERST#, but
the driver remains bound. The common DWC initialization path now
restores those registers while preserving its software resources. Tegra
therefore no longer needs to call dw_pcie_ep_cleanup() on each PERST#
cycle.
Remove the per-reset dw_pcie_ep_cleanup() call. The existing
dw_pcie_ep_init_registers() entry point now restores reset-lost
registers after the first initialization while retaining software
resources until final driver teardown. The allocation guards already
reuse the bitmaps, address array and per-function descriptors; this
change also avoids repeating the full debugfs/eDMA teardown and setup.
Keep the EPF deinit notification in the PERST# deassert path after
REFCLK is available and core reset has been deasserted, because EPF
deinit callbacks can clear BARs and need register access. The final
dw_pcie_ep_deinit() during driver removal still performs full cleanup.
Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
---
Changes V1 -> V2:
- Keep the existing dw_pcie_ep_init_registers() call now that it handles
both initial setup and reset recovery; only remove per-reset cleanup.
- Clarify the retained resource lifetimes and shorten the opening
paragraph to focus on the Tegra change.
drivers/pci/controller/dwc/pcie-tegra194.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index 0f49ea6df8bc..47a83a69533d 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, LINK_WIDTH_SPEED_CTRL);
val &= ~SPEED_CHANGE;
--
2.34.1
next prev parent reply other threads:[~2026-10-21 6:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-21 6:19 [PATCH v2 0/3] PCI: dwc: Avoid full EP cleanup " Manikanta Maddireddy
2026-10-21 6:19 ` [PATCH v2 1/3] PCI: dwc: Reuse Endpoint resources after fundamental reset Manikanta Maddireddy
2026-10-21 6:19 ` Manikanta Maddireddy [this message]
2026-10-21 6:19 ` [PATCH v2 3/3] PCI: tegra194: Notify Endpoint functions on PERST# assert Manikanta Maddireddy
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