From d684a90d38e24dcaf95fdb32c83efe05f80d152a Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 11 Nov 2015 16:27:33 -0800 Subject: ahci: per-port msix support Some AHCI controllers support per-port MSI-X vectors. At the same time the Linux AHCI driver needs to support one-off architectures that implement a single MSI-X vector for all ports. The heuristic for enabling AHCI ports becomes, in order of preference: 1/ per-port multi-MSI-X 2/ per-port multi-MSI 3/ single MSI 4/ single MSI-X 5/ legacy INTX This all depends on AHCI implementations with potentially broken MSI-X requesting less vectors than the number of ports. If this assumption is violated we will need to start explicitly white-listing AHCI-MSIX implementations. Reported-by: Ricardo Neri [ricardo: fix struct msix_entry handling] Reported-by: kernel test robot Signed-off-by: Dan Williams Signed-off-by: Tejun Heo --- drivers/ata/ahci.c | 67 ++++++++++++++++++++++++++++++++++++------------------ 1 file changed, 45 insertions(+), 22 deletions(-) (limited to 'drivers/ata/ahci.c') diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c index cdfbcc54821f..594fcabd22cd 100644 --- a/drivers/ata/ahci.c +++ b/drivers/ata/ahci.c @@ -1306,15 +1306,13 @@ static inline void ahci_gtf_filter_workaround(struct ata_host *host) #endif /* - * ahci_init_msix() only implements single MSI-X support, not multiple - * MSI-X per-port interrupts. This is needed for host controllers that only - * have MSI-X support implemented, but no MSI or intx. + * ahci_init_msix() - optionally enable per-port MSI-X otherwise defer + * to single msi. */ static int ahci_init_msix(struct pci_dev *pdev, unsigned int n_ports, - struct ahci_host_priv *hpriv) + struct ahci_host_priv *hpriv, unsigned long flags) { - int rc, nvec; - struct msix_entry entry = {}; + int nvec, i, rc; /* Do not init MSI-X if MSI is disabled for the device */ if (hpriv->flags & AHCI_HFLAG_NO_MSI) @@ -1324,22 +1322,39 @@ static int ahci_init_msix(struct pci_dev *pdev, unsigned int n_ports, if (nvec < 0) return nvec; - if (!nvec) { + /* + * Proper MSI-X implementations will have a vector per-port. + * Barring that, we prefer single-MSI over single-MSIX. If this + * check fails (not enough MSI-X vectors for all ports) we will + * be called again with the flag clear iff ahci_init_msi() + * fails. + */ + if (flags & AHCI_HFLAG_MULTI_MSIX) { + if (nvec < n_ports) + return -ENODEV; + nvec = n_ports; + } else if (nvec) { + nvec = 1; + } else { + /* + * Emit dev_err() since this was the non-legacy irq + * method of last resort. + */ rc = -ENODEV; goto fail; } - /* - * There can be more than one vector (e.g. for error detection or - * hdd hotplug). Only the first vector (entry.entry = 0) is used. - */ - rc = pci_enable_msix_exact(pdev, &entry, 1); + for (i = 0; i < nvec; i++) + hpriv->msix[i].entry = i; + rc = pci_enable_msix_exact(pdev, hpriv->msix, nvec); if (rc < 0) goto fail; - hpriv->irq = entry.vector; + if (nvec > 1) + hpriv->flags |= AHCI_HFLAG_MULTI_MSIX; + hpriv->irq = hpriv->msix[0].vector; /* for single msi-x */ - return 1; + return nvec; fail: dev_err(&pdev->dev, "failed to enable MSI-X with error %d, # of vectors: %d\n", @@ -1403,20 +1418,25 @@ static int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports, { int nvec; + /* + * Try to enable per-port MSI-X. If the host is not capable + * fall back to single MSI before finally attempting single + * MSI-X. + */ + nvec = ahci_init_msix(pdev, n_ports, hpriv, AHCI_HFLAG_MULTI_MSIX); + if (nvec >= 0) + return nvec; + nvec = ahci_init_msi(pdev, n_ports, hpriv); if (nvec >= 0) return nvec; - /* - * Currently, MSI-X support only implements single IRQ mode and - * exists for controllers which can't do other types of IRQ. Only - * set it up if MSI fails. - */ - nvec = ahci_init_msix(pdev, n_ports, hpriv); + /* try single-msix */ + nvec = ahci_init_msix(pdev, n_ports, hpriv, 0); if (nvec >= 0) return nvec; - /* lagacy intx interrupts */ + /* legacy intx interrupts */ pci_intx(pdev, 1); hpriv->irq = pdev->irq; @@ -1578,7 +1598,10 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent) if (!host) return -ENOMEM; host->private_data = hpriv; - + hpriv->msix = devm_kzalloc(&pdev->dev, + sizeof(struct msix_entry) * n_ports, GFP_KERNEL); + if (!hpriv->msix) + return -ENOMEM; ahci_init_interrupts(pdev, n_ports, hpriv); if (!(hpriv->cap & HOST_CAP_SSS) || ahci_ignore_sss) -- cgit