Commit f9eb654f authored by Krishna Chaitanya Chundru's avatar Krishna Chaitanya Chundru Committed by Manivannan Sadhasivam
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PCI: dwc: Update pci->num_lanes to maximum supported link width 



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: default avatarKrishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
[mani: reworded commit message a bit]
Signed-off-by: default avatarManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: default avatarManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://patch.msgid.link/20250328-preset_v6-v9-3-22cfa0490518@oss.qualcomm.com
parent 57a4591d

drivers/pci/controller/dwc/pcie-designware-host.c

+3 −0
Original line number Diff line number Diff line
@@ -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

drivers/pci/controller/dwc/pcie-designware.c

+8 −0
Original line number Diff line number Diff line
@@ -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;

drivers/pci/controller/dwc/pcie-designware.h

+1 −0
Original line number Diff line number Diff line
@@ -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,