From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1156A23392B; Sat, 30 May 2026 18:02:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780164163; cv=none; b=HuFMtDzfHj7RjQHaPAkWph49Op5JPRrAxEYKGuwtvWHcYOPcUlSTPidSrJDX5qh2qzwjXDAihARFBjPY7q9+r0A/9nFmLUs9mkGeeo+ILVqZfQNqOKLTjVjgGFDiQF7LeMplreuv9A1r5OV9oDpipiqyyYLbhN2mbym/7yAAcAw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780164163; c=relaxed/simple; bh=tJJVLUPIPTVnziNlZdMZMrWpYPs9dk4hDkvNd7X7PTo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MRqpFNSP5hAC9N3WRS6h+CqOfOXSnZIpCUku+r2Kdr5KhrAACnjdP70WgD6kKfrPglofiY4Qy+L8Af7wZFN6CpEw1qCDy9whu3Bbg/CutULc96ffg3qe5eqGlCXeqSVuzTqWJ2+a7OpoKkpRYvWIOx8BAn2cw4nn6QkrA9YcaIU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=CosHtZmV; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="CosHtZmV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 554691F00893; Sat, 30 May 2026 18:02:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780164162; bh=R8tttKc25KHhvWlnTyBupQxMX8JLSVAwagiDRQdBYlk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=CosHtZmVBTr5NV/a2PhrKY7nZocVi3mWEDKrv0f50Vn3hmBr/8nPGyByapRIzuijk ZVtC3orikr6M10WmJ3bhoNK6Xb49yxuZlXUO9bxvFLEyFIr3YqaUUKM7pywiaRWljj iXgmdh/ByUOuBzkiAHjrUy4JYLrrlhV3JC1UJSTo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Vidya Sagar , Manikanta Maddireddy , Manivannan Sadhasivam , Bjorn Helgaas , Jon Hunter , Sasha Levin Subject: [PATCH 5.15 473/776] PCI: tegra194: Disable LTSSM after transition to Detect on surprise link down Date: Sat, 30 May 2026 18:03:07 +0200 Message-ID: <20260530160252.568811696@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160240.228940103@linuxfoundation.org> References: <20260530160240.228940103@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Manikanta Maddireddy [ Upstream commit 9fa0c242f8d7acf1b124d4462d18f4023573ac1c ] After the link reaches a Detect-related LTSSM state, disable LTSSM so it does not keep toggling between Polling and Detect. Do this by polling for the Detect state first, then clearing APPL_CTRL_LTSSM_EN in both tegra_pcie_dw_pme_turnoff() and pex_ep_event_pex_rst_assert(). Fixes: 56e15a238d92 ("PCI: tegra: Add Tegra194 PCIe support") Signed-off-by: Vidya Sagar Signed-off-by: Manikanta Maddireddy Signed-off-by: Manivannan Sadhasivam Signed-off-by: Bjorn Helgaas Tested-by: Jon Hunter Reviewed-by: Jon Hunter Link: https://patch.msgid.link/20260324190755.1094879-4-mmaddireddy@nvidia.com Signed-off-by: Sasha Levin --- drivers/pci/controller/dwc/pcie-tegra194.c | 29 ++++++++++++---------- 1 file changed, 16 insertions(+), 13 deletions(-) diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c index a7ab82067d538..c32184e8e5636 100644 --- a/drivers/pci/controller/dwc/pcie-tegra194.c +++ b/drivers/pci/controller/dwc/pcie-tegra194.c @@ -1539,14 +1539,6 @@ static void tegra_pcie_dw_pme_turnoff(struct tegra_pcie_dw *pcie) data &= ~APPL_PINMUX_PEX_RST; appl_writel(pcie, data, APPL_PINMUX); - /* - * Some cards do not go to detect state even after de-asserting - * PERST#. So, de-assert LTSSM to bring link to detect state. - */ - data = readl(pcie->appl_base + APPL_CTRL); - data &= ~APPL_CTRL_LTSSM_EN; - writel(data, pcie->appl_base + APPL_CTRL); - err = readl_poll_timeout(pcie->appl_base + APPL_DEBUG, data, ((data & APPL_DEBUG_LTSSM_STATE_MASK) == LTSSM_STATE_DETECT_QUIET) || ((data & APPL_DEBUG_LTSSM_STATE_MASK) == LTSSM_STATE_DETECT_ACT) || @@ -1555,6 +1547,14 @@ static void tegra_pcie_dw_pme_turnoff(struct tegra_pcie_dw *pcie) LTSSM_DELAY_US, LTSSM_TIMEOUT_US); if (err) dev_info(pcie->dev, "LTSSM state: 0x%x detect timeout: %d\n", data, err); + + /* + * Deassert LTSSM state to stop the state toggling between + * Polling and Detect. + */ + data = readl(pcie->appl_base + APPL_CTRL); + data &= ~APPL_CTRL_LTSSM_EN; + writel(data, pcie->appl_base + APPL_CTRL); } /* * DBI registers may not be accessible after this as PLL-E would be @@ -1636,11 +1636,6 @@ static void pex_ep_event_pex_rst_assert(struct tegra_pcie_dw *pcie) if (pcie->ep_state == EP_STATE_DISABLED) return; - /* Disable LTSSM */ - val = appl_readl(pcie, APPL_CTRL); - val &= ~APPL_CTRL_LTSSM_EN; - appl_writel(pcie, val, APPL_CTRL); - ret = readl_poll_timeout(pcie->appl_base + APPL_DEBUG, val, ((val & APPL_DEBUG_LTSSM_STATE_MASK) == LTSSM_STATE_DETECT_QUIET) || ((val & APPL_DEBUG_LTSSM_STATE_MASK) == LTSSM_STATE_DETECT_ACT) || @@ -1651,6 +1646,14 @@ static void pex_ep_event_pex_rst_assert(struct tegra_pcie_dw *pcie) if (ret) dev_info(pcie->dev, "LTSSM state: 0x%x detect timeout: %d\n", val, ret); + /* + * Deassert LTSSM state to stop the state toggling between + * Polling and Detect. + */ + val = appl_readl(pcie, APPL_CTRL); + val &= ~APPL_CTRL_LTSSM_EN; + appl_writel(pcie, val, APPL_CTRL); + reset_control_assert(pcie->core_rst); tegra_pcie_disable_phy(pcie); -- 2.53.0