[PATCH v3 03/16] PCI: dwc: imx6: Use cached PCIe capability offset

Thus, the cached offset is available when these functions are called, and
DBI access occurs only after hardware is enabled.

Signed-off-by: Hans Zhang <[email protected]>
---
In pci-imx6, dw_pcie_find_capability() is called in the following
call chain:

  static const struct dw_pcie_ops dw_pcie_ops = {
    .start_link = imx_pcie_start_link,
  };
  imx_pcie_start_link()
    -> dw_pcie_find_capability()
    -> imx_pcie_ltssm_enable()
      -> dw_pcie_find_capability()

Replace these calls with the cached pci->pcie_cap. The call chain after
modification becomes:

  dw_pcie_host_init()
    -> pp->ops->init() [imx6_pcie_host_init]
    -> dw_pcie_get_pcie_cap()  (caches offset)
    -> pci->ops->start_link = imx_pcie_start_link
      -> uses pci->pcie_cap
      -> imx_pcie_ltssm_enable()
        -> uses pci->pcie_cap
---
 drivers/pci/controller/dwc/pci-imx6.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 98e1db751132..74b28b4df484 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -966,10 +966,10 @@ static void imx_pcie_ltssm_enable(struct device *dev)
 {
 	struct imx_pcie *imx_pcie = dev_get_drvdata(dev);
 	const struct imx_pcie_drvdata *drvdata = imx_pcie->drvdata;
-	u8 offset = dw_pcie_find_capability(imx_pcie->pci, PCI_CAP_ID_EXP);
+	struct dw_pcie *pci = imx_pcie->pci;
 	u32 tmp;
 
-	tmp = dw_pcie_readl_dbi(imx_pcie->pci, offset + PCI_EXP_LNKCAP);
+	tmp = dw_pcie_readl_dbi(pci, pci->pcie_cap + PCI_EXP_LNKCAP);
 	phy_set_speed(imx_pcie->phy, FIELD_GET(PCI_EXP_LNKCAP_SLS, tmp));
 	if (drvdata->ltssm_mask)
 		regmap_update_bits(imx_pcie->iomuxc_gpr, drvdata->ltssm_off, drvdata->ltssm_mask,
@@ -995,7 +995,7 @@ static int imx_pcie_start_link(struct dw_pcie *pci)
 {
 	struct imx_pcie *imx_pcie = to_imx_pcie(pci);
 	struct device *dev = pci->dev;
-	u8 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
+	u8 offset = pci->pcie_cap;
 	u32 tmp;
 	int ret;
 
-- 
2.34.1