From patchwork Fri Apr 4 08:22:24 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Manivannan Sadhasivam X-Patchwork-Id: 14038202 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 BFFBB194C86; Fri, 4 Apr 2025 08:22:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743754950; cv=none; b=Kv87iJ6mc0vpJkdY8MUmP5OAWzfQreTBe9eaYt+TzSb1Hgh9PgEtaOk7dkQk0NaKWCCavXpnVOnTEFG+DuqEQFwTWJtcInvwVDntZXUepdIkrlZfpPmVR8QgtnOWMVEwYzjfjE140LHQBa7ddb8Ec5I4+4/x2flID5jrf5xP1AY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743754950; c=relaxed/simple; bh=ffTrhsY9FJRcfVww9i0y0yxQfrwIq4gqaddUeXhlv5A=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=DU1SpfmG/06pgEITeOhkXHRV99GKV1Ga32zhYCHjWgIHn/blvunfDc1OCp9qzHGiuADmg51h6LXEsXyULAUWon20zxU8N0GilF9tdO7349iz+IswMQDNM2kq2TEyd8FG2dUH9I7lar7h1/HGZZIwH/uXH8K2N6qaqamjxX7/XtQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=D9ShQ6FP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="D9ShQ6FP" Received: by smtp.kernel.org (Postfix) with ESMTPS id 4899FC4CEF0; Fri, 4 Apr 2025 08:22:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743754950; bh=ffTrhsY9FJRcfVww9i0y0yxQfrwIq4gqaddUeXhlv5A=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=D9ShQ6FPlAhquV1oMV5an//O1orxi1OZg9wU398rNbW2M3N9VvAJgEOKL2J3utjoH LtND4CqPvQ3uY4FNuCwLUJo7wJlvomk/Dy8ruh00M5PEqIFeIx/tGcJe9KqQRf8XDB lwms0QcAXMnVI+t+i5NDq/jIvN03Iyy96ISpJPwU6qQGOe5pXbcZF/Xhbf9U7b7OJS ZKjfd/HgTk2XtpRw6cDnYYnjwyeNRFHxG9niMvhL2UZbuX1oA3bgnHd1wM3gwXUVPy NFPk2jVH9uJEfNEPyNmWYlDJNvrLUiG3l4NA0Nz7VnjG6eaPb29poVgL8z+U+vJVja XjS6YeDuMn3dA== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39BA7C3601E; Fri, 4 Apr 2025 08:22:30 +0000 (UTC) Date: Fri, 04 Apr 2025 13:52:24 +0530 Subject: [PATCH 4/4] PCI: qcom: Add support for resetting the slot due to link down event Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250404-pcie-reset-slot-v1-4-98952918bf90@linaro.org> References: <20250404-pcie-reset-slot-v1-0-98952918bf90@linaro.org> In-Reply-To: <20250404-pcie-reset-slot-v1-0-98952918bf90@linaro.org> To: Mahesh J Salgaonkar , Oliver O'Halloran , Bjorn Helgaas , Lorenzo Pieralisi , =?utf-8?q?Krzysztof_Wilczy?= =?utf-8?q?=C5=84ski?= , Rob Herring Cc: dingwei@marvell.com, cassel@kernel.org, Krishna Chaitanya Chundru , linuxppc-dev@lists.ozlabs.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, Manivannan Sadhasivam X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=6144; i=manivannan.sadhasivam@linaro.org; h=from:subject:message-id; bh=HLmverztHMHdlf6iHpfj2weCoSC+ZBfRtve4NgX9dNk=; b=owEBbQGS/pANAwAKAVWfEeb+kc71AcsmYgBn75bD4IKYNbv//nyxjS6fn8rRAv9TJ+ustu03A 5oBDvZ7iXWJATMEAAEKAB0WIQRnpUMqgUjL2KRYJ5dVnxHm/pHO9QUCZ++WwwAKCRBVnxHm/pHO 9QvcCACSocfRLEqKZDYj0W0aZt8ZpVhJGCB/hNr+d8Ytjf5Ygef2P6wt+710HTaKJwNdwjtJemr sZhT4x/YDMcUM0TpJvi5dksSBcntnglOMlNNMKN0HSfyXiDbFWK1TgO/nuvZFpvL9KeJiy4JAlm 1Ys94fK8eXXd7o/qsuIWTKIUSZT5fPgWCz11VNDSjieNKw2cZRxYiD41XxKpCwijWv+HZ95zd5X zFpKu6rnQibq6H+JASDtpXk8xg51Wd46Lb2O+7cDy7PGv8l7wBnTfyM9WTLTFA5VTmFo/kGIMID gzXXMn5zeJScJVqWdvgORCdygUDJhliN4Qi1EUQozbWJPIZu X-Developer-Key: i=manivannan.sadhasivam@linaro.org; a=openpgp; fpr=C668AEC3C3188E4C611465E7488550E901166008 X-Endpoint-Received: by B4 Relay for manivannan.sadhasivam@linaro.org/default with auth_id=185 X-Original-From: Manivannan Sadhasivam Reply-To: manivannan.sadhasivam@linaro.org From: Manivannan Sadhasivam From: Manivannan Sadhasivam The PCIe link can go down under circumstances such as the device firmware crash, link instability, etc... When that happens, the PCIe slot needs to be reset to make it operational again. Currently, the driver is not handling the link down event, due to which the users have to restart the machine to make PCIe link operational again. So fix it by detecting the link down event and adding support to resetting the slot. Since the Qcom PCIe controllers report the link down event through the 'global' IRQ, enable the link down event by setting PARF_INT_ALL_LINK_DOWN bit in PARF_INT_ALL_MASK register. Then in the case of the event, call pci_host_handle_link_down() API in the handler to let the PCI core handle the link down condition. The API will internally call, 'pci_host_bridge::reset_slot()' callback to reset the slot in a platform specific way. So implement the callback to reset the slot by first resetting the PCIe core, followed by reinitializing the resources and then finally starting the link again. Signed-off-by: Manivannan Sadhasivam --- drivers/pci/controller/dwc/pcie-qcom.c | 89 +++++++++++++++++++++++++++++++++- 1 file changed, 87 insertions(+), 2 deletions(-) diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c index dc98ae63362db0422384b1879a2b9a7dc564d091..b0df108fb4f3c6a8b8290062ecb3e1c5c34ddd4c 100644 --- a/drivers/pci/controller/dwc/pcie-qcom.c +++ b/drivers/pci/controller/dwc/pcie-qcom.c @@ -55,6 +55,7 @@ #define PARF_INT_ALL_STATUS 0x224 #define PARF_INT_ALL_CLEAR 0x228 #define PARF_INT_ALL_MASK 0x22c +#define PARF_STATUS 0x230 #define PARF_SID_OFFSET 0x234 #define PARF_BDF_TRANSLATE_CFG 0x24c #define PARF_DBI_BASE_ADDR_V2 0x350 @@ -130,8 +131,11 @@ /* PARF_LTSSM register fields */ #define LTSSM_EN BIT(8) +#define SW_CLEAR_FLUSH_MODE BIT(10) +#define FLUSH_MODE BIT(11) /* PARF_INT_ALL_{STATUS/CLEAR/MASK} register fields */ +#define PARF_INT_ALL_LINK_DOWN BIT(1) #define PARF_INT_ALL_LINK_UP BIT(13) #define PARF_INT_MSI_DEV_0_7 GENMASK(30, 23) @@ -145,6 +149,9 @@ /* PARF_BDF_TO_SID_CFG fields */ #define BDF_TO_SID_BYPASS BIT(0) +/* PARF_STATUS fields */ +#define FLUSH_COMPLETED BIT(8) + /* ELBI_SYS_CTRL register fields */ #define ELBI_SYS_CTRL_LT_ENABLE BIT(0) @@ -169,6 +176,7 @@ PCIE_CAP_SLOT_POWER_LIMIT_SCALE) #define PERST_DELAY_US 1000 +#define FLUSH_TIMEOUT_US 100 #define QCOM_PCIE_CRC8_POLYNOMIAL (BIT(2) | BIT(1) | BIT(0)) @@ -274,11 +282,14 @@ struct qcom_pcie { struct icc_path *icc_cpu; const struct qcom_pcie_cfg *cfg; struct dentry *debugfs; + int global_irq; bool suspended; bool use_pm_opp; }; #define to_qcom_pcie(x) dev_get_drvdata((x)->dev) +static int qcom_pcie_reset_slot(struct pci_host_bridge *bridge, + struct pci_dev *pdev); static void qcom_ep_reset_assert(struct qcom_pcie *pcie) { @@ -1263,6 +1274,8 @@ static int qcom_pcie_host_init(struct dw_pcie_rp *pp) goto err_assert_reset; } + pp->bridge->reset_slot = qcom_pcie_reset_slot; + return 0; err_assert_reset: @@ -1300,6 +1313,73 @@ static const struct dw_pcie_host_ops qcom_pcie_dw_ops = { .post_init = qcom_pcie_host_post_init, }; +static int qcom_pcie_reset_slot(struct pci_host_bridge *bridge, + struct pci_dev *pdev) +{ + struct pci_bus *bus = bridge->bus; + struct dw_pcie_rp *pp = bus->sysdata; + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); + struct qcom_pcie *pcie = to_qcom_pcie(pci); + struct device *dev = pcie->pci->dev; + u32 val; + int ret; + + /* Wait for the pending transactions to be completed */ + ret = readl_relaxed_poll_timeout(pcie->parf + PARF_STATUS, val, + val & FLUSH_COMPLETED, 10, + FLUSH_TIMEOUT_US); + if (ret) { + dev_err(dev, "Flush completion failed: %d\n", ret); + goto err_host_deinit; + } + + /* Clear the FLUSH_MODE to allow the core to be reset */ + val = readl(pcie->parf + PARF_LTSSM); + val |= SW_CLEAR_FLUSH_MODE; + writel(val, pcie->parf + PARF_LTSSM); + + /* Wait for the FLUSH_MODE to clear */ + ret = readl_relaxed_poll_timeout(pcie->parf + PARF_LTSSM, val, + !(val & FLUSH_MODE), 10, + FLUSH_TIMEOUT_US); + if (ret) { + dev_err(dev, "Flush mode clear failed: %d\n", ret); + goto err_host_deinit; + } + + qcom_pcie_host_deinit(pp); + + ret = qcom_pcie_host_init(pp); + if (ret) { + dev_err(dev, "Host init failed\n"); + return ret; + } + + ret = dw_pcie_setup_rc(pp); + if (ret) + goto err_host_deinit; + + /* + * Re-enable global IRQ events as the PARF_INT_ALL_MASK register is + * non-sticky. + */ + if (pcie->global_irq) + writel_relaxed(PARF_INT_ALL_LINK_UP | PARF_INT_ALL_LINK_DOWN | + PARF_INT_MSI_DEV_0_7, pcie->parf + PARF_INT_ALL_MASK); + + qcom_pcie_start_link(pci); + dw_pcie_wait_for_link(pci); + + dev_dbg(dev, "Slot reset completed\n"); + + return 0; + +err_host_deinit: + qcom_pcie_host_deinit(pp); + + return ret; +} + /* Qcom IP rev.: 2.1.0 Synopsys IP rev.: 4.01a */ static const struct qcom_pcie_ops ops_2_1_0 = { .get_resources = qcom_pcie_get_resources_2_1_0, @@ -1571,6 +1651,9 @@ static irqreturn_t qcom_pcie_global_irq_thread(int irq, void *data) pci_unlock_rescan_remove(); qcom_pcie_icc_opp_update(pcie); + } else if (FIELD_GET(PARF_INT_ALL_LINK_DOWN, status)) { + dev_dbg(dev, "Received Link down event\n"); + pci_host_handle_link_down(pp->bridge); } else { dev_WARN_ONCE(dev, 1, "Received unknown event. INT_STATUS: 0x%08x\n", status); @@ -1732,8 +1815,10 @@ static int qcom_pcie_probe(struct platform_device *pdev) goto err_host_deinit; } - writel_relaxed(PARF_INT_ALL_LINK_UP | PARF_INT_MSI_DEV_0_7, - pcie->parf + PARF_INT_ALL_MASK); + writel_relaxed(PARF_INT_ALL_LINK_UP | PARF_INT_ALL_LINK_DOWN | + PARF_INT_MSI_DEV_0_7, pcie->parf + PARF_INT_ALL_MASK); + + pcie->global_irq = irq; } qcom_pcie_icc_opp_update(pcie);