Commit da56a1bf authored by Ajay Agarwal's avatar Ajay Agarwal Committed by Lorenzo Pieralisi
Browse files

PCI: dwc: Wait for link up only if link is started 

In dw_pcie_host_init() regardless of whether the link has been
started or not, the code waits for the link to come up. Even in
cases where start_link() is not defined the code ends up spinning
in a loop for 1 second. Since in some systems dw_pcie_host_init()
gets called during probe, this one second loop for each pcie
interface instance ends up extending the boot time.

Wait for the link up in only if the start_link() is defined.

Link: https://lore.kernel.org/r/20230412093425.3659088-1-ajayagarwal@google.com


Tested-by: default avatarWill McVicker <willmcvicker@google.com>
Signed-off-by: default avatarSajid Dalvi <sdalvi@google.com>
Signed-off-by: default avatarAjay Agarwal <ajayagarwal@google.com>
Signed-off-by: default avatarLorenzo Pieralisi <lpieralisi@kernel.org>
parent ac9a7868

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

+9 −4
Original line number Diff line number Diff line
@@ -485,14 +485,19 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp) 
	if (ret)

		goto err_remove_edma;



	if (!dw_pcie_link_up(pci)) {

	if (dw_pcie_link_up(pci)) {

		dw_pcie_print_link_status(pci);

	} else {

		ret = dw_pcie_start_link(pci);

		if (ret)

			goto err_remove_edma;

	}



	/* Ignore errors, the link may come up later */

	dw_pcie_wait_for_link(pci);

		if (pci->ops && pci->ops->start_link) {

			ret = dw_pcie_wait_for_link(pci);

			if (ret)

				goto err_stop_link;

		}

	}



	bridge->sysdata = pp;

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

+13 −7
Original line number Diff line number Diff line
@@ -644,9 +644,20 @@ void dw_pcie_disable_atu(struct dw_pcie *pci, u32 dir, int index) 
	dw_pcie_writel_atu(pci, dir, index, PCIE_ATU_REGION_CTRL2, 0);

}



int dw_pcie_wait_for_link(struct dw_pcie *pci)

void dw_pcie_print_link_status(struct dw_pcie *pci)

{

	u32 offset, val;



	offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);

	val = dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKSTA);



	dev_info(pci->dev, "PCIe Gen.%u x%u link up\n",

		 FIELD_GET(PCI_EXP_LNKSTA_CLS, val),

		 FIELD_GET(PCI_EXP_LNKSTA_NLW, val));

}



int dw_pcie_wait_for_link(struct dw_pcie *pci)

{

	int retries;



	/* Check if the link is up or not */
@@ -662,12 +673,7 @@ int dw_pcie_wait_for_link(struct dw_pcie *pci) 
		return -ETIMEDOUT;

	}



	offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);

	val = dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKSTA);



	dev_info(pci->dev, "PCIe Gen.%u x%u link up\n",

		 FIELD_GET(PCI_EXP_LNKSTA_CLS, val),

		 FIELD_GET(PCI_EXP_LNKSTA_NLW, val));

	dw_pcie_print_link_status(pci);



	return 0;

}

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

+1 −0
Original line number Diff line number Diff line
@@ -429,6 +429,7 @@ void dw_pcie_setup(struct dw_pcie *pci); 
void dw_pcie_iatu_detect(struct dw_pcie *pci);

int dw_pcie_edma_detect(struct dw_pcie *pci);

void dw_pcie_edma_remove(struct dw_pcie *pci);

void dw_pcie_print_link_status(struct dw_pcie *pci);



static inline void dw_pcie_writel_dbi(struct dw_pcie *pci, u32 reg, u32 val)

{