On Fri, Jan 19, 2024 at 11:29:22PM +0530, Ajay Agarwal wrote:
> On Fri, Jan 19, 2024 at 01:22:19PM +0530, Manivannan Sadhasivam wrote:
> > On Fri, Jan 12, 2024 at 03:00:06PM +0530, Ajay Agarwal wrote:
> > > 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.
> > >
> >
> > Which platform you are working on? Is that upstreamed? You should mention the
> > specific platform where you are observing the issue.
> >
> This is for the Pixel phone platform. The platform driver for the same
> is not upstreamed yet. It is in the process.
>
Then you should submit this patch at the time of the driver submission. Right
now, you are trying to fix a problem which is not present in upstream. One can
argue that it is a problem for designware-plat driver, but honestly I do not
know how it works.
- Mani
> > Right now, intel-gw and designware-plat are the only drivers not defining that
> > callback. First one definitely needs a fixup and I do not know how the latter
> > works.
> >
> > - Mani
> >
> > > Wait for the link up in only if the start_link() is defined.
> > >
> > > Signed-off-by: Ajay Agarwal <ajayagarwal@xxxxxxxxxx>
> > > ---
> > > v4 was applied, but then reverted. The reason being v4 added a
> > > regression on some products which expect the link to not come up as a
> > > part of the probe. Since v4 returned error from dw_pcie_wait_for_link
> > > check, the probe function of these products started to fail.
> > >
> > > Changelog since v4:
> > > - Do not return error from dw_pcie_wait_for_link check
> > >
> > > .../pci/controller/dwc/pcie-designware-host.c | 12 +++++++----
> > > drivers/pci/controller/dwc/pcie-designware.c | 20 ++++++++++++-------
> > > drivers/pci/controller/dwc/pcie-designware.h | 1 +
> > > 3 files changed, 22 insertions(+), 11 deletions(-)
> > >
> > > diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> > > index 7991f0e179b2..e53132663d1d 100644
> > > --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> > > +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> > > @@ -487,14 +487,18 @@ 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) {
> > > + /* Ignore errors, the link may come up later */
> > > + dw_pcie_wait_for_link(pci);
> > > + }
> > > + }
> > >
> > > bridge->sysdata = pp;
> > >
> > > diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
> > > index 250cf7f40b85..c067d2e960cf 100644
> > > --- a/drivers/pci/controller/dwc/pcie-designware.c
> > > +++ b/drivers/pci/controller/dwc/pcie-designware.c
> > > @@ -645,9 +645,20 @@ 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 */
> > > @@ -663,12 +674,7 @@ 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;
> > > }
> > > diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> > > index 55ff76e3d384..164214a7219a 100644
> > > --- a/drivers/pci/controller/dwc/pcie-designware.h
> > > +++ b/drivers/pci/controller/dwc/pcie-designware.h
> > > @@ -447,6 +447,7 @@ 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);
> > >
> > > int dw_pcie_suspend_noirq(struct dw_pcie *pci);
> > > int dw_pcie_resume_noirq(struct dw_pcie *pci);
> > > --
> > > 2.43.0.381.gb435a96ce8-goog
> > >
> >
> > --
> > மணிவண்ணன் சதாசிவம்
--
மணிவண்ணன் சதாசிவம்
