Re: change MSI/MSI-X APIs

[christos%zoulas.com@localhost (Christos Zoulas)]

On May 14,  7:40pm, k-nakahara%iij.ad.jp@localhost (Kengo NAKAHARA) wrote:
-- Subject: Re: change MSI/MSI-X APIs

Thanks!

Here's a slightly modified version that gets rid of the flags and simplifies
the more common case.

The following could be an enum:

typedef int pci_intr_type_t;

#define PCI_INTR_TYPE_INTX 0
#define PCI_INTR_TYPE_MSI  1
#define PCI_INTR_TYPE_MSIX 2
#define PCI_INTR_TYPE_MAX  3

int
pci_intr_alloc(const struct pci_attach_args *, pci_intr_handle_t **ihps,
    int *counts, size_t ncounts);

If the counts[i] == 0, then you don't allocate, if it is -1, you allocate max,
otherwise you allocate up to count.

NULL in the counts means do whatever you think is best.
(I am passing the "ncounts" so that the API does not need to be versioned
if there are more interrupt flavors added)

pci_intr_type_t pci_intr_type(pci_intr_handle_t *ihp);

xxxx_attach()
{

We return a negative errno and a positive nintrs, so the common case where
the driver does not care:

	if  ((nintrs = pci_intr_alloc(*pa, &sc->sc_intrs, NULL, 0)) < 0) {
		error("foo %d\n", -nintrs);
		return;
	}

	for (i = 0; i < nintrs; i++)
		sc->sc_ihs[i] = pci_intr_establish(pc, sc->sc_intrs[i], level,
		    func, arg);

Otherwise if we want to be selective:

	int counts[PCI_INTR_TYPE_MAX];
	memset(counts, 0, sizeof(counts);

	// Don't want msi, leave it 0
	counts[PCI_INTR_TYPE_MSIX] = -1;
	counts[PCI_INTR_TYPE_INTX] = -1;

	if  ((nintrs = pci_intr_alloc(*pa, &sc->sc_intrs, counts,
	    PCI_INTR_TYPE_MAX)) < 0)
	    ....

What do you think?

christos