On Fri, Dec 03, 2021 at 10:36:00AM +0530, Kishon Vijay Abraham I wrote:
> Hi Kunihiko,
>
> On 01/09/21 10:46 am, Kunihiko Hayashi wrote:
> > The driver using core_init_notifier, e.g. pcie-tegra194.c, runs according
> > to the following sequence:
> >
> > probe()
> > dw_pcie_ep_init()
> >
> > bind()
> > dw_pcie_ep_start()
> > enable_irq()
> >
> > (interrupt occurred)
> > handler()
> > [enable controller]
> > dw_pcie_ep_init_complete()
> > dw_pcie_ep_init_notify()
> >
> > After receiving an interrupt from RC, the handler enables the controller
> > and the controller registers can be accessed.
> > So accessing the registers should do in dw_pcie_ep_init_complete().
> >
> > Currently dw_pcie_ep_init() has functions dw_iatu_detect() and
> > dw_pcie_ep_find_capability() that include accesses to DWC registers.
> > As a result, accessing the registers before enabling the controller,
> > the access will fail.
> >
> > The function dw_pcie_ep_init() shouldn't have any access to DWC registers
> > if the controller is enabled after calling bind(). This moves access codes
> > to DBI/iATU registers and depending variables from dw_pcie_ep_init() to
> > dw_pcie_ep_init_complete().
>
> Ideally pci_epc_create() should be the last step by the controller
> driver before handing the control to the core EPC framework. Since
> after this step the EPC framework can start invoking the epc_ops.
>
> Here more stuff is being added to dw_pcie_ep_init_complete() which is
> required for epc_ops and this could result in aborts for platforms
> which does not add core_init_notifier.
This patch needs rework, I will mark the series as "Changes requested".
Lorenzo
>
> Thanks,
> Kishon
>
> >
> > Cc: Xiaowei Bao <xiaowei.bao@xxxxxxx>
> > Cc: Vidya Sagar <vidyas@xxxxxxxxxx>
> > Fixes: 6bfc9c3a2c70 ("PCI: designware-ep: Move the function of getting MSI capability forward")
> > Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx>
> > Acked-by: Om Prakash Singh <omp@xxxxxxxxxx>
> > Reviewed-by: Vidya Sagar <vidyas@xxxxxxxxxx>
> > ---
> > drivers/pci/controller/dwc/pcie-designware-ep.c | 81 +++++++++++++------------
> > 1 file changed, 41 insertions(+), 40 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> > index 998b698..00ce83c 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> > +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
> > @@ -636,16 +636,56 @@ static unsigned int dw_pcie_ep_find_ext_capability(struct dw_pcie *pci, int cap)
> > int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep)
> > {
> > struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > + struct dw_pcie_ep_func *ep_func;
> > + struct device *dev = pci->dev;
> > unsigned int offset;
> > unsigned int nbars;
> > u8 hdr_type;
> > + u8 func_no;
> > + void *addr;
> > u32 reg;
> > int i;
> >
> > + 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;
> > +
> > + for (func_no = 0; func_no < ep->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);
> > + }
> > +
> > hdr_type = dw_pcie_readb_dbi(pci, PCI_HEADER_TYPE) &
> > PCI_HEADER_TYPE_MASK;
> > if (hdr_type != PCI_HEADER_TYPE_NORMAL) {
> > - dev_err(pci->dev,
> > + dev_err(dev,
> > "PCIe controller is not set to EP mode (hdr_type:0x%x)!\n",
> > hdr_type);
> > return -EIO;
> > @@ -674,8 +714,6 @@ 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);
> > @@ -683,7 +721,6 @@ 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;
> >
> > INIT_LIST_HEAD(&ep->func_list);
> >
> > @@ -705,8 +742,6 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> > }
> > }
> >
> > - dw_pcie_iatu_detect(pci);
> > -
> > res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "addr_space");
> > if (!res)
> > return -EINVAL;
> > @@ -714,26 +749,6 @@ 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);
> >
> > @@ -750,20 +765,6 @@ 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);
> > -
> > - list_add_tail(&ep_func->list, &ep->func_list);
> > - }
> > -
> > if (ep->ops->ep_init)
> > ep->ops->ep_init(ep);
> >
> >
