[PATCH v8 7/8] PCI: imx6: Disable clocks and regulators after link is down

Richard Zhu
2022-02-25T03:53:18Z

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