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From: Manikanta Maddireddy <mmaddireddy@nvidia.com>
To: <bhelgaas@google.com>, <lpieralisi@kernel.org>,
	<kwilczynski@kernel.org>, <mani@kernel.org>, <robh@kernel.org>,
	<krzk+dt@kernel.org>, <conor+dt@kernel.org>,
	<thierry.reding@gmail.com>, <jonathanh@nvidia.com>,
	<kishon@kernel.org>, <arnd@arndb.de>,
	<gregkh@linuxfoundation.org>, <Frank.Li@nxp.com>,
	<den@valinux.co.jp>, <hongxing.zhu@nxp.com>,
	<jingoohan1@gmail.com>, <vidyas@nvidia.com>, <cassel@kernel.org>,
	<18255117159@163.com>
Cc: <linux-pci@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>,
	Manikanta Maddireddy <mmaddireddy@nvidia.com>
Subject: [PATCH v7 07/13] PCI: tegra194: Set LTR message request before PCIe link up
Date: Tue, 3 Mar 2026 12:24:42 +0530	[thread overview]
Message-ID: <20260303065448.2361488-8-mmaddireddy@nvidia.com> (raw)
In-Reply-To: <20260303065448.2361488-1-mmaddireddy@nvidia.com>

From: Vidya Sagar <vidyas@nvidia.com>

LTR message should be sent as soon as the Root Port enables LTR in the
Endpoint. Set snoop & no snoop LTR timing and LTR message request before
PCIe links up. This ensures that LTR message is sent upstream as soon as
LTR is enabled.

Fixes: c57247f940e8 ("PCI: tegra: Add support for PCIe endpoint mode in Tegra194")
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
---
Changes V6 -> V7: Retain FIELD_PREP() usage
Changes V1 -> V6: None

 drivers/pci/controller/dwc/pcie-tegra194.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index 2da3478f0b5f..b50229df890e 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -485,15 +485,6 @@ static irqreturn_t tegra_pcie_ep_irq_thread(int irq, void *arg)
 	if (val & PCI_COMMAND_MASTER) {
 		ktime_t timeout;
 
-		/* 110us for both snoop and no-snoop */
-		val = FIELD_PREP(PCI_LTR_VALUE_MASK, 110) |
-		      FIELD_PREP(PCI_LTR_SCALE_MASK, 2) |
-		      LTR_MSG_REQ |
-		      FIELD_PREP(PCI_LTR_NOSNOOP_VALUE, 110) |
-		      FIELD_PREP(PCI_LTR_NOSNOOP_SCALE, 2) |
-		      LTR_NOSNOOP_MSG_REQ;
-		appl_writel(pcie, val, APPL_LTR_MSG_1);
-
 		/* Send LTR upstream */
 		val = appl_readl(pcie, APPL_LTR_MSG_2);
 		val |= APPL_LTR_MSG_2_LTR_MSG_REQ_STATE;
@@ -1803,6 +1794,15 @@ static void pex_ep_event_pex_rst_deassert(struct tegra_pcie_dw *pcie)
 	val |= APPL_INTR_EN_L1_0_0_RDLH_LINK_UP_INT_EN;
 	appl_writel(pcie, val, APPL_INTR_EN_L1_0_0);
 
+	/* 110us for both snoop and no-snoop */
+	val = FIELD_PREP(PCI_LTR_VALUE_MASK, 110) |
+	      FIELD_PREP(PCI_LTR_SCALE_MASK, 2) |
+	      LTR_MSG_REQ |
+	      FIELD_PREP(PCI_LTR_NOSNOOP_VALUE, 110) |
+	      FIELD_PREP(PCI_LTR_NOSNOOP_SCALE, 2) |
+	      LTR_NOSNOOP_MSG_REQ;
+	appl_writel(pcie, val, APPL_LTR_MSG_1);
+
 	reset_control_deassert(pcie->core_rst);
 
 	val = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
-- 
2.34.1


  parent reply	other threads:[~2026-03-03  6:56 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-03  6:54 [PATCH v7 00/13] Fixes to pcie-tegra194 driver Manikanta Maddireddy
2026-03-03  6:54 ` [PATCH v7 01/13] PCI: tegra194: Fix polling delay for L2 state Manikanta Maddireddy
2026-03-03  6:54 ` [PATCH v7 02/13] PCI: tegra194: Refactor LTSSM state polling on surprise down Manikanta Maddireddy
2026-03-05  9:31   ` Manivannan Sadhasivam
2026-03-03  6:54 ` [PATCH v7 03/13] PCI: tegra194: Don't force the device into the D0 state before L2 Manikanta Maddireddy
2026-03-05  9:40   ` Manivannan Sadhasivam
2026-03-15 13:21     ` Manikanta Maddireddy
2026-03-16  1:25       ` Manivannan Sadhasivam
2026-03-03  6:54 ` [PATCH v7 04/13] PCI: tegra194: Disable PERST IRQ only in Endpoint mode Manikanta Maddireddy
2026-03-03  6:54 ` [PATCH v7 05/13] PCI: tegra194: Use devm_gpiod_get_optional() to parse "nvidia,refclk-select" Manikanta Maddireddy
2026-03-03  6:54 ` [PATCH v7 06/13] PCI: tegra194: Disable direct speed change for EP Manikanta Maddireddy
2026-03-05  9:43   ` Manivannan Sadhasivam
2026-03-15 13:44     ` Manikanta Maddireddy
2026-03-16  1:27       ` Manivannan Sadhasivam
2026-03-03  6:54 ` Manikanta Maddireddy [this message]
2026-03-05 10:18   ` [PATCH v7 07/13] PCI: tegra194: Set LTR message request before PCIe link up Manivannan Sadhasivam
2026-03-15 13:49     ` Manikanta Maddireddy
2026-03-16  1:28       ` Manivannan Sadhasivam
2026-03-03  6:54 ` [PATCH v7 08/13] PCI: tegra194: Apply pinctrl settings for both PCIe RP and EP Manikanta Maddireddy
2026-03-05 10:19   ` Manivannan Sadhasivam
2026-03-15 13:54     ` Manikanta Maddireddy
2026-03-16  1:31       ` Manivannan Sadhasivam
2026-03-16  3:41         ` Manikanta Maddireddy
2026-03-16  4:26           ` Manivannan Sadhasivam
2026-03-03  6:54 ` [PATCH v7 09/13] PCI: tegra194: Allow system suspend when the Endpoint link is not up Manikanta Maddireddy
2026-03-05 10:29   ` Manivannan Sadhasivam
2026-03-15 14:10     ` Manikanta Maddireddy
2026-03-16  1:34       ` Manivannan Sadhasivam
2026-03-03  6:54 ` [PATCH v7 10/13] PCI: tegra194: Free up EP resources during remove() Manikanta Maddireddy
2026-03-03  6:54 ` [PATCH v7 11/13] PCI: tegra194: Use HW version number Manikanta Maddireddy
2026-03-05 10:34   ` Manivannan Sadhasivam
2026-03-03  6:54 ` [PATCH v7 12/13] PCI: tegra194: Fix CBB timeout caused by DBI access before core power-on Manikanta Maddireddy
2026-03-03  6:54 ` [PATCH v7 13/13] PCI: tegra194: Free resources during controller deinitialization Manikanta Maddireddy
2026-03-05 10:43   ` Manivannan Sadhasivam
2026-03-15 14:16     ` Manikanta Maddireddy
2026-03-16  1:35       ` Manivannan Sadhasivam

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