[PATCH v2] AHCI: Add generic MSI-X interrupt support to SATA PCI driver
From: tj@kernel.org (Tejun Heo)
Date: 2015-05-04 16:07:12
Also in:
linux-ide, lkml
Hello, Robert. (cc'ing Alexander for ahci msi) On Mon, May 04, 2015 at 09:45:37AM +0200, Robert Richter wrote:
From: Robert Richter <redacted> 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.
quoted hunk ↗ jump to hunk
@@ -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?
quoted hunk ↗ jump to hunk
+ 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