[PATCH v3 03/16] PCI: dwc: imx6: Use cached PCIe capability offset
From: Hans Zhang <18255117159@163.com>
Date: 2026-07-20 15:08:23
Also in:
imx, linux-amlogic, linux-arm-msm, linux-pci, linux-riscv, linux-rockchip, linux-tegra, lkml, spacemit
Subsystem:
pci driver for imx6, pci native host bridge and endpoint drivers, pci subsystem, the rest · Maintainers:
Richard Zhu, Lucas Stach, Lorenzo Pieralisi, Krzysztof Wilczyński, Manivannan Sadhasivam, Bjorn Helgaas, Linus Torvalds
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 <18255117159@163.com>
---
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