Messages in this thread | | | Date | Mon, 17 Oct 2022 11:06:48 +0100 | From | Jonathan Cameron <> | Subject | Re: [PATCH 1/2] cxl/pci: Add generic MSI/MSI-X interrupt support |
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On Sun, 16 Oct 2022 17:37:07 -0700 Davidlohr Bueso <dave@stgolabs.net> wrote:
> On Sun, 16 Oct 2022, Ira Weiny wrote: > > >> +enum { > >> + CXL_IRQ_NONE, > >> + CXL_IRQ_MSI, > >> +}; > > > >I don't recall this being in v1? > > No, it wasn't. I added it because it was a clean way of doing the irq setup > for each interested party in it's own setup call (such as I do in patch 2). > Jonathan preferred it this way... but per all the below, it seems actually > better to stick with the original plan and do the request_irq for all > interested parties at once, after a succesful call to cxl_pci_alloc_irq_vectors(). > > > > >Right now do we have any users who will register irq's without having MSI > >support? > > We don't, and as you know, the fw interrupts thing is only for events; so > actually if we were to have any kind of flags, I guess a cxlds->has_msi > boolean would do, instead of the enum. But the below voids this I guess.
I still want that bool for the PMUs. Might not apply everywhere but IRQ setup for the PMU at least is a job for the cpmu driver, not the pci driver.
Just call it has_int though to avoid the msi/msix naming confusion. Also, might just be local to function initializing the various other devices, so passed in as a parameter to those calls so they can do what they like with it.
> > > > >> + > >> /* CXL 2.0 8.2.8.1 Device Capabilities Array Register */ > >> #define CXLDEV_CAP_ARRAY_OFFSET 0x0 > >> #define CXLDEV_CAP_ARRAY_CAP_ID 0 > >> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h > >> index 88e3a8e54b6a..ca020767f7fc 100644 > >> --- a/drivers/cxl/cxlmem.h > >> +++ b/drivers/cxl/cxlmem.h > >> @@ -247,6 +247,8 @@ struct cxl_dev_state { > >> > >> struct xarray doe_mbs; > >> > >> + int irq_type; > >> + > >> int (*mbox_send)(struct cxl_dev_state *cxlds, struct cxl_mbox_cmd *cmd); > >> }; > >> > >> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c > >> index faeb5d9d7a7a..942c4449d30f 100644 > >> --- a/drivers/cxl/pci.c > >> +++ b/drivers/cxl/pci.c > >> @@ -428,6 +428,67 @@ static void devm_cxl_pci_create_doe(struct cxl_dev_state *cxlds) > >> } > >> } > >> > >> +/** > >> + * struct cxl_irq_cap - CXL feature that is capable of receiving MSI/MSI-X irqs. > >> + * > >> + * @name: Name of the device generating this interrupt. > >> + * @get_max_msgnum: Get the feature's largest interrupt message number. If the > >> + * feature does not have the Interrupt Supported bit set, then > >> + * return -1. > >> + */ > >> +struct cxl_irq_cap { > >> + const char *name; > >> + int (*get_max_msgnum)(struct cxl_dev_state *cxlds); > >> +}; > >> + > >> +static const struct cxl_irq_cap cxl_irq_cap_table[] = { NULL }; > >> + > >> +static void cxl_pci_free_irq_vectors(void *data) > >> +{ > >> + pci_free_irq_vectors(data); > >> +} > >> + > >> +/* > >> + * Attempt to allocate the largest amount of necessary vectors. > >> + * > >> + * Returns 0 upon a successful allocation of *all* vectors, or a > >> + * negative value otherwise. > >> + */ > >> +static int cxl_pci_alloc_irq_vectors(struct cxl_dev_state *cxlds) > >> +{ > >> + struct device *dev = cxlds->dev; > >> + struct pci_dev *pdev = to_pci_dev(dev); > >> + int rc, i, vectors = -1; > >> + > >> + for (i = 0; i < ARRAY_SIZE(cxl_irq_cap_table); i++) { > >> + int irq; > >> + > >> + if (!cxl_irq_cap_table[i].get_max_msgnum) > >> + continue; > >> + > >> + irq = cxl_irq_cap_table[i].get_max_msgnum(cxlds); > >> + vectors = max_t(int, irq, vectors); > >> + } > >> + > >> + if (vectors == -1) > >> + return -1; > >> + > >> + vectors++; > >> + rc = pci_alloc_irq_vectors(pdev, vectors, vectors, > >> + PCI_IRQ_MSIX | PCI_IRQ_MSI); > > > >Yea without PCI_IRQ_LEGACY I don't think we need any communication about which > >type of vectors were allocated. > > > >Basically if cxl_pci_alloc_irq_vectors() is successful all users can assume > >that at least MSI is available... > > Agreed, and that's why I added the flag to indicate to the users if the previous > cxl_pci_alloc_irq_vectors() call had been successful or not, basically to avoid > having them unnecessarily attempt to install their isr. But again all this was > because the request_irq() calls were now going to be in each component setup. > > > > >For the mailboxes they could key off of the message number being set in cxlds. > > > >> + if (rc < 0) > >> + return rc; > >> + > >> + if (rc != vectors) { > >> + dev_err(dev, "Not enough interrupts; use polling instead.\n"); > >> + /* some got allocated, clean them up */ > >> + cxl_pci_free_irq_vectors(pdev); > >> + return -ENOSPC; > >> + } > >> + > >> + return devm_add_action_or_reset(dev, cxl_pci_free_irq_vectors, pdev); > >> +} > >> + > >> static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > >> { > >> struct cxl_register_map map; > >> @@ -478,6 +539,11 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > >> > >> devm_cxl_pci_create_doe(cxlds); > >> > >> + if (!cxl_pci_alloc_irq_vectors(cxlds)) > > > >This can't be here for the event stuff because I need the mailboxes set up to > >find out the message numbers for those events. I had a hell of a time by > >accident putting it here. :-( > > I'm fine with putting this back down, right before the devm_cxl_add_memdev().
Ah. I'd missed that subtlety.
> > > > >> + cxlds->irq_type = CXL_IRQ_MSI; > >> + else > >> + cxlds->irq_type = CXL_IRQ_NONE; > >> + > >> rc = cxl_pci_setup_mailbox(cxlds); > >> if (rc) > >> return rc; > > > >Can't the mailbox irq's be set up after this call? Mailbox access during set > >up is probably fine using polling, right? > > Again, fine by me. So we'd end up in the original: > > if (!cxl_pci_alloc_irq_vectors(cxlds)) { > cxl_mbox_setup_irq(); > cxl_events_setup_irq(); > cxl_pmu_setup_irq(); > }
For the pmu just pass a flag into the existing setup call, I don't want to see separate setup of irqs from the rest of the setup. Not sure how this works out for the other cases.
Jonathan
> > Thanks, > Davidlohr
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