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PCI: dwc: Update pci->num_lanes to maximum supported link width

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If the num-lanes property is not present in the devicetree, update
pci->num_lanes with the hardware supported maximum link width using
the newly introduced dw_pcie_link_get_max_link_width() API.

The API is used to get the Maximum Link Width (MLW) of the controller.

Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
[mani: reworded commit message a bit]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://patch.msgid.link/20250328-preset_v6-v9-3-22cfa0490518@oss.qualcomm.com
This commit is contained in:
Krishna Chaitanya Chundru 2025-03-28 15:58:31 +05:30 committed by Manivannan Sadhasivam
parent 57a4591df7
commit f9eb654fb1
3 changed files with 12 additions and 0 deletions
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3
drivers/pci/controller/dwc/pcie-designware-host.c
View File

@ -523,6 +523,9 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
dw_pcie_iatu_detect(pci);
if (pci->num_lanes < 1)
pci->num_lanes = dw_pcie_link_get_max_link_width(pci);
/*
* Allocate the resource for MSG TLP before programming the iATU
* outbound window in dw_pcie_setup_rc(). Since the allocation depends

8
drivers/pci/controller/dwc/pcie-designware.c
View File

@ -781,6 +781,14 @@ static void dw_pcie_link_set_max_speed(struct dw_pcie *pci)
}
int dw_pcie_link_get_max_link_width(struct dw_pcie *pci)
{
u8 cap = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
u32 lnkcap = dw_pcie_readl_dbi(pci, cap + PCI_EXP_LNKCAP);
return FIELD_GET(PCI_EXP_LNKCAP_MLW, lnkcap);
}
static void dw_pcie_link_set_max_link_width(struct dw_pcie *pci, u32 num_lanes)
{
u32 lnkcap, lwsc, plc;

1
drivers/pci/controller/dwc/pcie-designware.h
View File

@ -540,6 +540,7 @@ void dw_pcie_write_dbi2(struct dw_pcie *pci, u32 reg, size_t size, u32 val);
int dw_pcie_link_up(struct dw_pcie *pci);
void dw_pcie_upconfig_setup(struct dw_pcie *pci);
int dw_pcie_wait_for_link(struct dw_pcie *pci);
int dw_pcie_link_get_max_link_width(struct dw_pcie *pci);
int dw_pcie_prog_outbound_atu(struct dw_pcie *pci,
const struct dw_pcie_ob_atu_cfg *atu);
int dw_pcie_prog_inbound_atu(struct dw_pcie *pci, int index, int type,