392ee1e6dd
There are two ways pci_save_state and pci_restore_state are used. As helper functions during suspend/resume, and as helper functions around a hardware reset event. When used as helper functions around a hardware reset event there is no reason to believe the calls will be paired, nor is there a good reason to believe that if we restore the msi state from before the reset that it will match the current msi state. Since arch code may change the msi message without going through the driver, drivers currently do not have enough information to even know when to call pci_save_state to ensure they will have msi state in sync with the other kernel irq reception data structures. It turns out the solution is straight forward, cache the state in the existing msi data structures (not the magic pci saved things) and have the msi code update the cached state each time we write to the hardware. This means we never need to read the hardware to figure out what the hardware state should be. By modifying the caching in this manner we get to remove our save_state routines and only need to provide restore_state routines. The only fields that were at all tricky to regenerate were the msi and msi-x control registers and the way we regenerate them currently is a bit dependent upon assumptions on how we use the allow msi registers to be configured and used making the code a little bit brittle. If we ever change what cases we allow or how we configure the msi bits we can address the fragility then. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Acked-by: Auke Kok <auke-jan.h.kok@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
46 lines
1.2 KiB
C
46 lines
1.2 KiB
C
#ifndef LINUX_MSI_H
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#define LINUX_MSI_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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extern void mask_msi_irq(unsigned int irq);
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extern void unmask_msi_irq(unsigned int irq);
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extern void read_msi_msg(unsigned int irq, struct msi_msg *msg);
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extern 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 type : 5; /* {0: unused, 5h:MSI, 11h:MSI-X} */
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__u8 maskbit : 1; /* mask-pending bit supported ? */
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__u8 masked : 1;
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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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struct {
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__u16 head;
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__u16 tail;
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}link;
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void __iomem *mask_base;
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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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};
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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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#endif /* LINUX_MSI_H */
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