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From:   Richard Zhu <hongxing.zhu@nxp.com>
To:     l.stach@pengutronix.de, bhelgaas@google.com, broonie@kernel.org,
        lorenzo.pieralisi@arm.com, jingoohan1@gmail.com,
        festevam@gmail.com, francesco.dolcini@toradex.com
Cc:     hongxing.zhu@nxp.com, linux-pci@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        kernel@pengutronix.de, linux-imx@nxp.com
Subject: [PATCH v8 7/8] PCI: imx6: Disable clocks and regulators after link is down
Date:   Fri, 25 Feb 2022 11:44:26 +0800
Message-Id: <1645760667-10510-8-git-send-email-hongxing.zhu@nxp.com>
In-Reply-To: <1645760667-10510-1-git-send-email-hongxing.zhu@nxp.com>
References: <1645760667-10510-1-git-send-email-hongxing.zhu@nxp.com>
Precedence: bulk

Since i.MX PCIe doesn't support hot-plug, reduce power consumption
as much as possible by disabling clocks and regulators and returning
error when the link is down.

Add a new host_exit() callback for i.MX PCIe driver to disable the clocks,
regulators and so on in the error handling after host_init is finished.

Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 34 +++++++++++++++++++++++----
 1 file changed, 29 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 160a0bd02098..f8b15f0bc9ce 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -849,7 +849,9 @@ static int imx6_pcie_start_link(struct dw_pcie *pci)
 	/* Start LTSSM. */
 	imx6_pcie_ltssm_enable(dev);
 
-	dw_pcie_wait_for_link(pci);
+	ret = dw_pcie_wait_for_link(pci);
+	if (ret)
+		goto err_out;
 
 	if (pci->link_gen == 2) {
 		/* Allow Gen2 mode after the link is up. */
@@ -880,12 +882,14 @@ static int imx6_pcie_start_link(struct dw_pcie *pci)
 			ret = imx6_pcie_wait_for_speed_change(imx6_pcie);
 			if (ret) {
 				dev_err(dev, "Failed to bring link up!\n");
-				goto err_reset_phy;
+				goto err_out;
 			}
 		}
 
 		/* Make sure link training is finished as well! */
-		dw_pcie_wait_for_link(pci);
+		ret = dw_pcie_wait_for_link(pci);
+		if (ret)
+			goto err_out;
 	} else {
 		dev_info(dev, "Link: Gen2 disabled\n");
 	}
@@ -894,11 +898,10 @@ static int imx6_pcie_start_link(struct dw_pcie *pci)
 	dev_info(dev, "Link up, Gen%i\n", tmp & PCI_EXP_LNKSTA_CLS);
 	return 0;
 
-err_reset_phy:
+err_out:
 	dev_dbg(dev, "PHY DEBUG_R0=0x%08x DEBUG_R1=0x%08x\n",
 		dw_pcie_readl_dbi(pci, PCIE_PORT_DEBUG0),
 		dw_pcie_readl_dbi(pci, PCIE_PORT_DEBUG1));
-	imx6_pcie_reset_phy(imx6_pcie);
 	return ret;
 }
 
@@ -922,8 +925,29 @@ static int imx6_pcie_host_init(struct pcie_port *pp)
 	return 0;
 }
 
+static void imx6_pcie_host_exit(struct pcie_port *pp)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct device *dev = pci->dev;
+	struct imx6_pcie *imx6_pcie = to_imx6_pcie(pci);
+
+	imx6_pcie_reset_phy(imx6_pcie);
+	imx6_pcie_clk_disable(imx6_pcie);
+	switch (imx6_pcie->drvdata->variant) {
+	case IMX8MM:
+		if (phy_power_off(imx6_pcie->phy))
+			dev_err(dev, "unable to power off phy\n");
+		break;
+	default:
+		break;
+	}
+	if (imx6_pcie->vpcie)
+		regulator_disable(imx6_pcie->vpcie);
+}
+
 static const struct dw_pcie_host_ops imx6_pcie_host_ops = {
 	.host_init = imx6_pcie_host_init,
+	.host_exit = imx6_pcie_host_exit,
 };
 
 static const struct dw_pcie_ops dw_pcie_ops = {
-- 
2.25.1