[PATCH v3 05/16] PCI: dwc: meson: Use cached PCIe capability offset
From: Hans Zhang <18255117159@163.com>
Date: 2026-07-20 15:08:15
Also in:
imx, linux-amlogic, linux-arm-msm, linux-pci, linux-riscv, linux-rockchip, linux-tegra, lkml, spacemit
Subsystem:
pci native host bridge and endpoint drivers, pci subsystem, pcie driver for amlogic meson, the rest · Maintainers:
Lorenzo Pieralisi, Krzysztof Wilczyński, Manivannan Sadhasivam, Bjorn Helgaas, Yue Wang, Linus Torvalds
dw_pcie_host_init() calls pp->ops->init (meson_pcie_host_init) before
caching the offset. Therefore, inside .init we must call
dw_pcie_get_pcie_cap() to obtain the offset (the helper will perform the
DBI read and cache the result). This is safe because the hardware is
already enabled by the driver's own initialization.
Signed-off-by: Hans Zhang <18255117159@163.com>
---
In pci-meson, the call chain is:
static const struct dw_pcie_host_ops meson_pcie_host_ops = {
.init = meson_pcie_host_init,
};
meson_pcie_host_init()
-> meson_set_max_payload()
-> dw_pcie_find_capability()
-> meson_set_max_rd_req_size()
-> dw_pcie_find_capability()
---
drivers/pci/controller/dwc/pci-meson.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/controller/dwc/pci-meson.c b/drivers/pci/controller/dwc/pci-meson.c
index 7a4da9fae1ea..c9d0388d262b 100644
--- a/drivers/pci/controller/dwc/pci-meson.c
+++ b/drivers/pci/controller/dwc/pci-meson.c@@ -277,7 +277,7 @@ static void meson_set_max_payload(struct meson_pcie *mp, int size) { struct dw_pcie *pci = &mp->pci; u32 val; - u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); + u8 offset = dw_pcie_get_pcie_cap(pci); int max_payload_size = meson_size_to_payload(mp, size); val = dw_pcie_readl_dbi(pci, offset + PCI_EXP_DEVCTL);
@@ -293,7 +293,7 @@ static void meson_set_max_rd_req_size(struct meson_pcie *mp, int size) { struct dw_pcie *pci = &mp->pci; u32 val; - u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); + u8 offset = dw_pcie_get_pcie_cap(pci); int max_rd_req_size = meson_size_to_payload(mp, size); val = dw_pcie_readl_dbi(pci, offset + PCI_EXP_DEVCTL);
--
2.34.1