Hello Serge,
> From: Serge Semin, Sent: Monday, June 5, 2023 5:06 PM
>
> On Wed, May 10, 2023 at 03:22:20PM +0900, Yoshihiro Shimoda wrote:
> > Add support for triggering INTx IRQs by using outbound iATU.
> > Outbound iATU is utilized to send assert and de-assert INTx TLPs.
> > The message is generated based on the payloadless Msg TLP with type
> > 0x14, where 0x4 is the routing code implying the Terminate at
> > Receiver message. The message code is specified as b1000xx for
> > the INTx assertion and b1001xx for the INTx de-assertion.
> >
> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> > ---
> > .../pci/controller/dwc/pcie-designware-ep.c | 66 +++++++++++++++++--
> > drivers/pci/controller/dwc/pcie-designware.h | 2 +
> > 2 files changed, 64 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> > index fe2e0d765be9..0abc0073b1cf 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> > +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
> > @@ -6,9 +6,11 @@
> > * Author: Kishon Vijay Abraham I <kishon@xxxxxx>
> > */
> >
> > +#include <linux/delay.h>
> > #include <linux/of.h>
> > #include <linux/platform_device.h>
> >
> > +#include "../../pci.h"
> > #include "pcie-designware.h"
> > #include <linux/pci-epc.h>
> > #include <linux/pci-epf.h>
> > @@ -484,14 +486,57 @@ static const struct pci_epc_ops epc_ops = {
> > .get_features = dw_pcie_ep_get_features,
> > };
> >
> > +static int dw_pcie_ep_send_msg(struct dw_pcie_ep *ep, u8 func_no, u8 code,
> > + u8 routing)
> > +{
> > + struct dw_pcie_ob_atu_cfg atu = { 0 };
> > + struct pci_epc *epc = ep->epc;
> > + int ret;
> > +
> > + atu.func_no = func_no;
> > + atu.code = code;
> > + atu.routing = routing;
> > + atu.type = PCIE_ATU_TYPE_MSG;
> > + atu.cpu_addr = ep->intx_mem_phys;
> > + atu.size = epc->mem->window.page_size;
> > +
> > + ret = dw_pcie_ep_outbound_atu(ep, &atu);
> > + if (ret)
> > + return ret;
> > +
> > + writel(0, ep->intx_mem);
> > +
> > + dw_pcie_ep_unmap_addr(epc, func_no, 0, ep->intx_mem_phys);
> > +
> > + return 0;
> > +}
> > +
> > int dw_pcie_ep_raise_intx_irq(struct dw_pcie_ep *ep, u8 func_no)
> > {
> > struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > struct device *dev = pci->dev;
> > + int ret;
> >
> > - dev_err(dev, "EP cannot trigger INTx IRQs\n");
> > + if (!ep->intx_mem) {
> > + dev_err(dev, "INTx not supported\n");
> > + return -EOPNOTSUPP;
> > + }
> >
> > - return -EINVAL;
> > + /*
>
> > + * According to the document of PCIe, the INTx emulation should be
> > + * level-triggered. However, the Linux PCIe Endpoint framework only
> > + * supports edge-triggered for now. So, this function asserts INTx for
> > + * 50 usec, and then deasserts it.
>
> "Document of PCIe"?)
> What about the next message:
> Even though the PCI bus specification implies the level-triggered INTx
> interrupts the kernel PCIe endpoint framework has a single
> PCI_EPC_IRQ_INTx flag defined for the legacy IRQs simulation. Thus
> this function sends the Deassert_INTx PCIe TLP after the Assert_INTx
> message with the 50 usec duration basically implementing the
> rising-edge triggering IRQ. Hopefully the interrupt controller will
> still be able to register the incoming IRQ event...
Thank you for your suggestion! I'll use your comment on v17.
> Other than that the change looks good.
Thanks!
Best regards,
Yoshihiro Shimoda
> -Serge(y)
>
> > + */
> > + ret = dw_pcie_ep_send_msg(ep, func_no, PCI_CODE_ASSERT_INTA,
> > + PCI_MSG_ROUTING_LOCAL);
> > + if (ret)
> > + return ret;
> > +
> > + usleep_range(50, 100);
> > +
> > + return dw_pcie_ep_send_msg(ep, func_no, PCI_CODE_DEASSERT_INTA,
> > + PCI_MSG_ROUTING_LOCAL);
> > }
> > EXPORT_SYMBOL_GPL(dw_pcie_ep_raise_intx_irq);
> >
> > @@ -622,6 +667,10 @@ void dw_pcie_ep_exit(struct dw_pcie_ep *ep)
> >
> > dw_pcie_edma_remove(pci);
> >
> > + if (ep->intx_mem)
> > + pci_epc_mem_free_addr(epc, ep->intx_mem_phys, ep->intx_mem,
> > + epc->mem->window.page_size);
> > +
> > pci_epc_mem_free_addr(epc, ep->msi_mem_phys, ep->msi_mem,
> > epc->mem->window.page_size);
> >
> > @@ -793,9 +842,14 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> > goto err_exit_epc_mem;
> > }
> >
> > + ep->intx_mem = pci_epc_mem_alloc_addr(epc, &ep->intx_mem_phys,
> > + epc->mem->window.page_size);
> > + if (!ep->intx_mem)
> > + dev_warn(dev, "Failed to reserve memory for INTx\n");
> > +
> > ret = dw_pcie_edma_detect(pci);
> > if (ret)
> > - goto err_free_epc_mem;
> > + goto err_free_epc_mem_intx;
> >
> > if (ep->ops->get_features) {
> > epc_features = ep->ops->get_features(ep);
> > @@ -812,7 +866,11 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> > err_remove_edma:
> > dw_pcie_edma_remove(pci);
> >
> > -err_free_epc_mem:
> > +err_free_epc_mem_intx:
> > + if (ep->intx_mem)
> > + pci_epc_mem_free_addr(epc, ep->intx_mem_phys, ep->intx_mem,
> > + epc->mem->window.page_size);
> > +
> > pci_epc_mem_free_addr(epc, ep->msi_mem_phys, ep->msi_mem,
> > epc->mem->window.page_size);
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> > index c83d1d176e62..06e044e2163a 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware.h
> > +++ b/drivers/pci/controller/dwc/pcie-designware.h
> > @@ -369,6 +369,8 @@ struct dw_pcie_ep {
> > unsigned long *ob_window_map;
> > void __iomem *msi_mem;
> > phys_addr_t msi_mem_phys;
> > + void __iomem *intx_mem;
> > + phys_addr_t intx_mem_phys;
> > struct pci_epf_bar *epf_bar[PCI_STD_NUM_BARS];
> > };
> >
> > --
> > 2.25.1
> >
