65f6ae66a6
Because of the encoding of the "Multiple Message Capable" and "Multiple Message Enable" fields, a device can only advertise that it's capable of a power-of-two number of vectors, and the OS can only enable a power-of-two number. For example, a device that's limited internally to using 18 vectors would have to advertise that it's capable of 32. The 14 extra vectors consume vector numbers and IRQ descriptors even though the device can't actually use them. This fix introduces a 'msi_desc::nvec_used' field to address this issue. When non-zero, it is the actual number of MSIs the device will send, as requested by the device driver. This value should be used by architectures to set up and tear down only as many interrupt resources as the device will actually use. Note, although the existing 'msi_desc::multiple' field might seem redundant, in fact it is not. The number of MSIs advertised need not be the smallest power-of-two larger than the number of MSIs the device will send. Thus, it is not always possible to derive the former from the latter, so we need to keep them both to handle this case. [bhelgaas: changelog, rename to "nvec_used"] Signed-off-by: Alexander Gordeev <agordeev@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
63 lines
1.8 KiB
C
63 lines
1.8 KiB
C
#ifndef LINUX_MSI_H
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#define LINUX_MSI_H
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#include <linux/kobject.h>
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#include <linux/list.h>
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struct msi_msg {
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u32 address_lo; /* low 32 bits of msi message address */
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u32 address_hi; /* high 32 bits of msi message address */
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u32 data; /* 16 bits of msi message data */
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};
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/* Helper functions */
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struct irq_data;
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struct msi_desc;
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void mask_msi_irq(struct irq_data *data);
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void unmask_msi_irq(struct irq_data *data);
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void __read_msi_msg(struct msi_desc *entry, struct msi_msg *msg);
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void __get_cached_msi_msg(struct msi_desc *entry, struct msi_msg *msg);
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void __write_msi_msg(struct msi_desc *entry, struct msi_msg *msg);
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void read_msi_msg(unsigned int irq, struct msi_msg *msg);
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void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg);
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void write_msi_msg(unsigned int irq, struct msi_msg *msg);
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struct msi_desc {
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struct {
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__u8 is_msix : 1;
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__u8 multiple: 3; /* log2 number of messages */
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__u8 maskbit : 1; /* mask-pending bit supported ? */
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__u8 is_64 : 1; /* Address size: 0=32bit 1=64bit */
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__u8 pos; /* Location of the msi capability */
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__u16 entry_nr; /* specific enabled entry */
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unsigned default_irq; /* default pre-assigned irq */
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} msi_attrib;
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u32 masked; /* mask bits */
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unsigned int irq;
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unsigned int nvec_used; /* number of messages */
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struct list_head list;
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union {
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void __iomem *mask_base;
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u8 mask_pos;
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};
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struct pci_dev *dev;
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/* Last set MSI message */
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struct msi_msg msg;
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struct kobject kobj;
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};
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/*
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* The arch hook for setup up msi irqs
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*/
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int arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc);
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void arch_teardown_msi_irq(unsigned int irq);
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int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type);
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void arch_teardown_msi_irqs(struct pci_dev *dev);
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int arch_msi_check_device(struct pci_dev* dev, int nvec, int type);
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#endif /* LINUX_MSI_H */
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