diff options
Diffstat (limited to 'kernel/irq/msi.c')
-rw-r--r-- | kernel/irq/msi.c | 86 |
1 files changed, 78 insertions, 8 deletions
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c index 3fa4bd59f569..2f3c4f5382cc 100644 --- a/kernel/irq/msi.c +++ b/kernel/irq/msi.c @@ -16,6 +16,8 @@ #include <linux/msi.h> #include <linux/slab.h> +#include "internals.h" + /** * alloc_msi_entry - Allocate an initialize msi_entry * @dev: Pointer to the device for which this is allocated @@ -100,13 +102,14 @@ int msi_domain_set_affinity(struct irq_data *irq_data, return ret; } -static void msi_domain_activate(struct irq_domain *domain, - struct irq_data *irq_data) +static int msi_domain_activate(struct irq_domain *domain, + struct irq_data *irq_data, bool early) { struct msi_msg msg; BUG_ON(irq_chip_compose_msi_msg(irq_data, &msg)); irq_chip_write_msi_msg(irq_data, &msg); + return 0; } static void msi_domain_deactivate(struct irq_domain *domain, @@ -336,6 +339,40 @@ int msi_domain_populate_irqs(struct irq_domain *domain, struct device *dev, return ret; } +/* + * Carefully check whether the device can use reservation mode. If + * reservation mode is enabled then the early activation will assign a + * dummy vector to the device. If the PCI/MSI device does not support + * masking of the entry then this can result in spurious interrupts when + * the device driver is not absolutely careful. But even then a malfunction + * of the hardware could result in a spurious interrupt on the dummy vector + * and render the device unusable. If the entry can be masked then the core + * logic will prevent the spurious interrupt and reservation mode can be + * used. For now reservation mode is restricted to PCI/MSI. + */ +static bool msi_check_reservation_mode(struct irq_domain *domain, + struct msi_domain_info *info, + struct device *dev) +{ + struct msi_desc *desc; + + if (domain->bus_token != DOMAIN_BUS_PCI_MSI) + return false; + + if (!(info->flags & MSI_FLAG_MUST_REACTIVATE)) + return false; + + if (IS_ENABLED(CONFIG_PCI_MSI) && pci_msi_ignore_mask) + return false; + + /* + * Checking the first MSI descriptor is sufficient. MSIX supports + * masking and MSI does so when the maskbit is set. + */ + desc = first_msi_entry(dev); + return desc->msi_attrib.is_msix || desc->msi_attrib.maskbit; +} + /** * msi_domain_alloc_irqs - Allocate interrupts from a MSI interrupt domain * @domain: The domain to allocate from @@ -350,9 +387,11 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev, { struct msi_domain_info *info = domain->host_data; struct msi_domain_ops *ops = info->ops; - msi_alloc_info_t arg; + struct irq_data *irq_data; struct msi_desc *desc; + msi_alloc_info_t arg; int i, ret, virq; + bool can_reserve; ret = msi_domain_prepare_irqs(domain, dev, nvec, &arg); if (ret) @@ -373,13 +412,17 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev, return ret; } - for (i = 0; i < desc->nvec_used; i++) + for (i = 0; i < desc->nvec_used; i++) { irq_set_msi_desc_off(virq, i, desc); + irq_debugfs_copy_devname(virq + i, dev); + } } if (ops->msi_finish) ops->msi_finish(&arg, 0); + can_reserve = msi_check_reservation_mode(domain, info, dev); + for_each_msi_entry(desc, dev) { virq = desc->irq; if (desc->nvec_used == 1) @@ -392,15 +435,42 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev, * the MSI entries before the PCI layer enables MSI in the * card. Otherwise the card latches a random msi message. */ - if (info->flags & MSI_FLAG_ACTIVATE_EARLY) { - struct irq_data *irq_data; + if (!(info->flags & MSI_FLAG_ACTIVATE_EARLY)) + continue; + irq_data = irq_domain_get_irq_data(domain, desc->irq); + if (!can_reserve) + irqd_clr_can_reserve(irq_data); + ret = irq_domain_activate_irq(irq_data, can_reserve); + if (ret) + goto cleanup; + } + + /* + * If these interrupts use reservation mode, clear the activated bit + * so request_irq() will assign the final vector. + */ + if (can_reserve) { + for_each_msi_entry(desc, dev) { irq_data = irq_domain_get_irq_data(domain, desc->irq); - irq_domain_activate_irq(irq_data); + irqd_clr_activated(irq_data); } } - return 0; + +cleanup: + for_each_msi_entry(desc, dev) { + struct irq_data *irqd; + + if (desc->irq == virq) + break; + + irqd = irq_domain_get_irq_data(domain, desc->irq); + if (irqd_is_activated(irqd)) + irq_domain_deactivate_irq(irqd); + } + msi_domain_free_irqs(domain, dev); + return ret; } /** |