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Date: Sat, 9 Jul 2022 11:34:39 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To: Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
Cc: kishon@...com, bhelgaas@...gle.com, robh@...nel.org,
lorenzo.pieralisi@....com, kw@...ux.com, linux-pci@...r.kernel.org,
linux-kernel@...r.kernel.org, Om Prakash Singh <omp@...dia.com>,
Vidya Sagar <vidyas@...dia.com>
Subject: Re: [PATCH] PCI: designware-ep: Move DBI access to init_complete if
notifier is used
On Sat, Jul 09, 2022 at 10:42:32AM +0900, Kunihiko Hayashi wrote:
> Hi Manivannan,
>
> On 2022/07/08 1:57, Manivannan Sadhasivam wrote:
> > On Wed, Apr 27, 2022 at 03:48:26PM +0530, Manivannan Sadhasivam wrote:
> > > On Wed, Mar 30, 2022 at 11:35:15AM +0530, Manivannan Sadhasivam wrote:
> > > > For controllers supporting the CORE_INIT notifier, the resources are
> > > > supposed to be enabled in the init_complete function. Currently,
> > > > these controllers are enabling the resources during probe time due to
> > > > the DBI access happens in dw_pcie_ep_init().
> > > >
> > > > This creates the dependency with the host PCIe controller since the
> > > > resource enablement like PHY depends on host PCIe to be up. For the
> > > > standalone endpoint usecase, this would never work. So let's move all
> > > > DBI
> > > > access to init_complete function if CORE_INIT notifier is used. For the
> > > > controllers those doesn't support this notifier, this change is a NO-OP.
> > > >
> > > > Cc: Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
> > > > Cc: Om Prakash Singh <omp@...dia.com>
> > > > Cc: Vidya Sagar <vidyas@...dia.com>
> > > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
> > >
> > > A gentle ping on this patch!
> > >
>
> Sorry I couldn't check it.
> I think the original source seems to have changed in the latest, so please
> rebase and fix some conflicts.
>
Sure, will do.
> > Ping again!
> >
> > Thanks,
> > Mani
> >
> > > Thanks,
> > > Mani
> > >
> > > > ---
> > > > .../pci/controller/dwc/pcie-designware-ep.c | 138 ++++++++++++------
> > > > drivers/pci/controller/dwc/pcie-designware.h | 1 +
> > > > 2 files changed, 94 insertions(+), 45 deletions(-)
> > > >
> > > > diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c
> > > > b/drivers/pci/controller/dwc/pcie-designware-ep.c
> > > > index 0eda8236c125..fb2bf4bf5ba0 100644
> > > > --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> > > > +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
> > > > @@ -636,6 +636,63 @@ static unsigned int
> > > > dw_pcie_ep_find_ext_capability(struct dw_pcie *pci, int cap)
> > > > return 0;
> > > > }
> > > >
> > > > +static int dw_pcie_iatu_config(struct dw_pcie_ep *ep)
> > > > +{
> > > > + struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > > > + struct device *dev = pci->dev;
> > > > + void *addr;
> > > > +
> > > > + dw_pcie_iatu_detect(pci);
> > > > +
> > > > + ep->ib_window_map = devm_kcalloc(dev,
> > > > + BITS_TO_LONGS(pci->num_ib_windows),
> > > > + sizeof(long),
> > > > + GFP_KERNEL);
> > > > + if (!ep->ib_window_map)
> > > > + return -ENOMEM;
> > > > +
> > > > + ep->ob_window_map = devm_kcalloc(dev,
> > > > + BITS_TO_LONGS(pci->num_ob_windows),
> > > > + sizeof(long),
> > > > + GFP_KERNEL);
> > > > + if (!ep->ob_window_map)
> > > > + return -ENOMEM;
> > > > +
> > > > + addr = devm_kcalloc(dev, pci->num_ob_windows, sizeof(phys_addr_t),
> > > > + GFP_KERNEL);
> > > > + if (!addr)
> > > > + return -ENOMEM;
> > > > +
> > > > + ep->outbound_addr = addr;
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +static int dw_pcie_ep_func_init(struct dw_pcie_ep *ep)
> > > > +{
> > > > + struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > > > + struct dw_pcie_ep_func *ep_func;
> > > > + struct pci_epc *epc = ep->epc;
> > > > + struct device *dev = pci->dev;
> > > > + u8 func_no;
> > > > +
> > > > + for (func_no = 0; func_no < epc->max_functions; func_no++) {
> > > > + ep_func = devm_kzalloc(dev, sizeof(*ep_func), GFP_KERNEL);
> > > > + if (!ep_func)
> > > > + return -ENOMEM;
> > > > +
> > > > + ep_func->func_no = func_no;
> > > > + ep_func->msi_cap = dw_pcie_ep_find_capability(ep, func_no,
> > > > + PCI_CAP_ID_MSI);
> > > > + ep_func->msix_cap = dw_pcie_ep_find_capability(ep, func_no,
> > > > + PCI_CAP_ID_MSIX);
> > > > +
> > > > + list_add_tail(&ep_func->list, &ep->func_list);
> > > > + }
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep)
> > > > {
> > > > struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > > > @@ -643,7 +700,22 @@ int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep)
> > > > unsigned int nbars;
> > > > u8 hdr_type;
> > > > u32 reg;
> > > > - int i;
> > > > + int ret, i;
> > > > +
> > > > + if (ep->core_init_notifier) {
> > > > + ret = dw_pcie_iatu_config(ep);
> > > > + if (ret)
> > > > + return ret;
> > > > + }
> > > > +
> > > > + if (ep->core_init_notifier) {
> > > > + ret = dw_pcie_ep_func_init(ep);
> > > > + if (ret)
> > > > + return ret;
> > > > +
> > > > + if (ep->ops->ep_init)
> > > > + ep->ops->ep_init(ep);
> > > > + }
>
> It isn't necessary to divide function calls under same condition
> (ep->core_init_notifier).
>
Right. I think one of the part came from previous patch, so I forgot to merge
them.
> > > >
> > > > hdr_type = dw_pcie_readb_dbi(pci, PCI_HEADER_TYPE) &
> > > > PCI_HEADER_TYPE_MASK;
> > > > @@ -677,8 +749,6 @@ EXPORT_SYMBOL_GPL(dw_pcie_ep_init_complete);
> > > > int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> > > > {
> > > > int ret;
> > > > - void *addr;
> > > > - u8 func_no;
> > > > struct resource *res;
> > > > struct pci_epc *epc;
> > > > struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > > > @@ -686,7 +756,12 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> > > > struct platform_device *pdev = to_platform_device(dev);
> > > > struct device_node *np = dev->of_node;
> > > > const struct pci_epc_features *epc_features;
> > > > - struct dw_pcie_ep_func *ep_func;
> > > > +
> > > > + if (ep->ops->get_features) {
> > > > + epc_features = ep->ops->get_features(ep);
> > > > + if (epc_features->core_init_notifier)
> > > > + ep->core_init_notifier = true;
> > > > + }
> > > >
> > > > INIT_LIST_HEAD(&ep->func_list);
> > > >
> > > > @@ -708,7 +783,11 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> > > > }
> > > > }
> > > >
> > > > - dw_pcie_iatu_detect(pci);
> > > > + if (!ep->core_init_notifier) {
> > > > + ret = dw_pcie_iatu_config(ep);
> > > > + if (ret)
> > > > + return ret;
> > > > + }
> > > >
> > > > res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > > > "addr_space");
> > > > if (!res)
> > > > @@ -717,26 +796,6 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> > > > ep->phys_base = res->start;
> > > > ep->addr_size = resource_size(res);
> > > >
> > > > - ep->ib_window_map = devm_kcalloc(dev,
> > > > - BITS_TO_LONGS(pci->num_ib_windows),
> > > > - sizeof(long),
> > > > - GFP_KERNEL);
> > > > - if (!ep->ib_window_map)
> > > > - return -ENOMEM;
> > > > -
> > > > - ep->ob_window_map = devm_kcalloc(dev,
> > > > - BITS_TO_LONGS(pci->num_ob_windows),
> > > > - sizeof(long),
> > > > - GFP_KERNEL);
> > > > - if (!ep->ob_window_map)
> > > > - return -ENOMEM;
> > > > -
> > > > - addr = devm_kcalloc(dev, pci->num_ob_windows, sizeof(phys_addr_t),
> > > > - GFP_KERNEL);
> > > > - if (!addr)
> > > > - return -ENOMEM;
> > > > - ep->outbound_addr = addr;
> > > > -
> > > > if (pci->link_gen < 1)
> > > > pci->link_gen = of_pci_get_max_link_speed(np);
> > > >
> > > > @@ -753,23 +812,15 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> > > > if (ret < 0)
> > > > epc->max_functions = 1;
> > > >
> > > > - for (func_no = 0; func_no < epc->max_functions; func_no++) {
> > > > - ep_func = devm_kzalloc(dev, sizeof(*ep_func), GFP_KERNEL);
> > > > - if (!ep_func)
> > > > - return -ENOMEM;
> > > > -
> > > > - ep_func->func_no = func_no;
> > > > - ep_func->msi_cap = dw_pcie_ep_find_capability(ep, func_no,
> > > > - PCI_CAP_ID_MSI);
> > > > - ep_func->msix_cap = dw_pcie_ep_find_capability(ep, func_no,
> > > > - PCI_CAP_ID_MSIX);
> > > > + if (!ep->core_init_notifier) {
> > > > + ret = dw_pcie_ep_func_init(ep);
> > > > + if (ret)
> > > > + return ret;
> > > >
> > > > - list_add_tail(&ep_func->list, &ep->func_list);
> > > > + if (ep->ops->ep_init)
> > > > + ep->ops->ep_init(ep);
> > > > }
> > > >
> > > > - if (ep->ops->ep_init)
> > > > - ep->ops->ep_init(ep);
> > > > -
> > > > ret = pci_epc_mem_init(epc, ep->phys_base, ep->addr_size,
> > > > ep->page_size);
> > > > if (ret < 0) {
> > > > @@ -784,12 +835,9 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> > > > return -ENOMEM;
> > > > }
> > > >
> > > > - if (ep->ops->get_features) {
> > > > - epc_features = ep->ops->get_features(ep);
> > > > - if (epc_features->core_init_notifier)
> > > > - return 0;
> > > > - }
> > > > + if (!ep->core_init_notifier)
> > > > + return dw_pcie_ep_init_complete(ep);
> > > >
> > > > - return dw_pcie_ep_init_complete(ep);
> > > > + return 0;
> > > > }
> > > > EXPORT_SYMBOL_GPL(dw_pcie_ep_init);
>
> Since devm_pci_epc_create() is called in dw_pcie_ep_init(), EPC functions
> are available at this time, however, the driver can't access any controller
> registers until PERST# signal interrupt occurs.
>
> I think that EPC functions aren't called until PERST# signal, but
> I'm worried about whether controller access will occur.
>
Most of the EPC accesses are carried out by EPF and that won't be available
until dw_pcie_ep_init_complete() gets completed for core_init_notifier case.
This is one of the concerns Kishon raised but I think here we are safe.
Thanks,
Mani
> > > > diff --git a/drivers/pci/controller/dwc/pcie-designware.h
> > > > b/drivers/pci/controller/dwc/pcie-designware.h
> > > > index 7d6e9b7576be..aadb14159df7 100644
> > > > --- a/drivers/pci/controller/dwc/pcie-designware.h
> > > > +++ b/drivers/pci/controller/dwc/pcie-designware.h
> > > > @@ -242,6 +242,7 @@ struct dw_pcie_ep {
> > > > void __iomem *msi_mem;
> > > > phys_addr_t msi_mem_phys;
> > > > struct pci_epf_bar *epf_bar[PCI_STD_NUM_BARS];
> > > > + bool core_init_notifier;
> > > > };
> > > >
> > > > struct dw_pcie_ops {
> > > > --
> > > > 2.25.1
> > > >
>
> Thank you,
>
> ---
> Best Regards
> Kunihiko Hayashi
--
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