7589670f37
Direct Cache Access (DCA) is a method for warming the CPU cache before data
is used, with the intent of lessening the impact of cache misses. This
patch adds a manager and interface for matching up client requests for DCA
services with devices that offer DCA services.
In order to use DCA, a module must do bus writes with the appropriate tag
bits set to trigger a cache read for a specific CPU. However, different
CPUs and chipsets can require different sets of tag bits, and the methods
for determining the correct bits may be simple hardcoding or may be a
hardware specific magic incantation. This interface is a way for DCA
clients to find the correct tag bits for the targeted CPU without needing
to know the specifics.
[Dave Miller] use DEFINE_SPINLOCK()
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
47 lines
1.4 KiB
C
47 lines
1.4 KiB
C
#ifndef DCA_H
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#define DCA_H
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/* DCA Provider API */
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/* DCA Notifier Interface */
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void dca_register_notify(struct notifier_block *nb);
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void dca_unregister_notify(struct notifier_block *nb);
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#define DCA_PROVIDER_ADD 0x0001
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#define DCA_PROVIDER_REMOVE 0x0002
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struct dca_provider {
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struct dca_ops *ops;
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struct class_device *cd;
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int id;
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};
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struct dca_ops {
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int (*add_requester) (struct dca_provider *, struct device *);
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int (*remove_requester) (struct dca_provider *, struct device *);
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u8 (*get_tag) (struct dca_provider *, int cpu);
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};
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struct dca_provider *alloc_dca_provider(struct dca_ops *ops, int priv_size);
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void free_dca_provider(struct dca_provider *dca);
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int register_dca_provider(struct dca_provider *dca, struct device *dev);
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void unregister_dca_provider(struct dca_provider *dca);
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static inline void *dca_priv(struct dca_provider *dca)
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{
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return (void *)dca + sizeof(struct dca_provider);
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}
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/* Requester API */
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int dca_add_requester(struct device *dev);
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int dca_remove_requester(struct device *dev);
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u8 dca_get_tag(int cpu);
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/* internal stuff */
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int __init dca_sysfs_init(void);
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void __exit dca_sysfs_exit(void);
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int dca_sysfs_add_provider(struct dca_provider *dca, struct device *dev);
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void dca_sysfs_remove_provider(struct dca_provider *dca);
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int dca_sysfs_add_req(struct dca_provider *dca, struct device *dev, int slot);
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void dca_sysfs_remove_req(struct dca_provider *dca, int slot);
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#endif /* DCA_H */
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