Hello, Robert. (cc'ing Alexander for ahci msi)
On Mon, May 04, 2015 at 09:45:37AM +0200, Robert Richter wrote:
> From: Robert Richter <rrichter@xxxxxxxxxx>
>
> This patch adds generic support for MSI-X interrupts to the SATA PCI
> driver. Only single interrupt support is implemented. Thus, per-port
> interrupts can not yet be enabled.
>
> The driver now checks the device for the existence of MSI-X and tries
> to enable the interrupt. Otherwise, if a device is not MSI-X capable,
> the initialization is skipped and MSI or intx interrupts are
> configured.
>
> This patch also enables AHCI for Cavium Thunder SoCs that uses MSI-X.
Please don't mix these two changes in the same patch.
> @@ -1202,11 +1207,41 @@ static inline void ahci_gtf_filter_workaround(struct ata_host *host)
> {}
> #endif
>
> -static int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
> - struct ahci_host_priv *hpriv)
> +static int ahci_init_msix(struct pci_dev *pdev, unsigned int n_ports,
> + struct ahci_host_priv *hpriv)
> +{
> + int rc, nvec;
> + struct msix_entry entry = {};
> +
> + /* check if msix is supported */
> + nvec = pci_msix_vec_count(pdev);
> + if (nvec <= 0)
> + return 0;
> +
> + /* per-port msix interrupts are not supported */
> + if (n_ports > 1 && nvec >= n_ports)
> + return -ENOSYS;
Hmm... can you please elaborate why the condition isn't nvec > 1?
Also, shouldn't we be printing a warning message here explaining why
probing is failing?
> +
> + /* only enable the first entry (entry.entry = 0) */
> + rc = pci_enable_msix_exact(pdev, &entry, 1);
So, enabling the first msix works if nvec > 1 && nvec < n_ports but
not if nvec >= n_ports?
> + if (rc < 0)
> + return rc;
> +
> + return 1;
> +}
> +
> +static int __ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
> + struct ahci_host_priv *hpriv)
> {
> int rc, nvec;
>
> + nvec = ahci_init_msix(pdev, n_ports, hpriv);
> + if (nvec > 0)
> + return nvec;
> +
> + if (nvec && nvec != -ENOSYS)
> + dev_err(&pdev->dev, "failed to enable MSI-X: %d", nvec);
> +
> if (hpriv->flags & AHCI_HFLAG_NO_MSI)
> goto intx;
>
> @@ -1250,6 +1285,35 @@ static int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
> return 0;
> }
>
> +static struct msi_desc *msix_get_desc(struct pci_dev *dev, u16 entry)
> +{
> + struct msi_desc *desc;
> +
> + list_for_each_entry(desc, &dev->msi_list, list) {
> + if (desc->msi_attrib.entry_nr == entry)
> + return desc;
> + }
> +
> + return NULL;
> +}
> +
> +static int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
> + struct ahci_host_priv *hpriv)
> +{
> + struct msi_desc *desc;
> +
> + __ahci_init_interrupts(pdev, n_ports, hpriv);
> +
> + if (!pdev->msix_enabled)
> + return pdev->irq;
> +
> + desc = msix_get_desc(pdev, 0); /* first entry */
> + if (!desc)
> + return -ENODEV;
> +
> + return desc->irq;
> +}
Can we please do this properly? We should be able to move port priv
allocation to host allocaotion time and add and use pp->irq instead,
right?
Thanks.
--
tejun
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