kernel-ark/include/linux/dca.h
Shannon Nelson 7589670f37 DCA: Add Direct Cache Access driver
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>
2007-10-16 09:43:09 -07:00

48 lines
1.4 KiB
C

#ifndef DCA_H
#define DCA_H
/* DCA Provider API */
/* DCA Notifier Interface */
void dca_register_notify(struct notifier_block *nb);
void dca_unregister_notify(struct notifier_block *nb);
#define DCA_PROVIDER_ADD 0x0001
#define DCA_PROVIDER_REMOVE 0x0002
struct dca_provider {
struct dca_ops *ops;
struct class_device *cd;
int id;
};
struct dca_ops {
int (*add_requester) (struct dca_provider *, struct device *);
int (*remove_requester) (struct dca_provider *, struct device *);
u8 (*get_tag) (struct dca_provider *, int cpu);
};
struct dca_provider *alloc_dca_provider(struct dca_ops *ops, int priv_size);
void free_dca_provider(struct dca_provider *dca);
int register_dca_provider(struct dca_provider *dca, struct device *dev);
void unregister_dca_provider(struct dca_provider *dca);
static inline void *dca_priv(struct dca_provider *dca)
{
return (void *)dca + sizeof(struct dca_provider);
}
/* Requester API */
int dca_add_requester(struct device *dev);
int dca_remove_requester(struct device *dev);
u8 dca_get_tag(int cpu);
/* internal stuff */
int __init dca_sysfs_init(void);
void __exit dca_sysfs_exit(void);
int dca_sysfs_add_provider(struct dca_provider *dca, struct device *dev);
void dca_sysfs_remove_provider(struct dca_provider *dca);
int dca_sysfs_add_req(struct dca_provider *dca, struct device *dev, int slot);
void dca_sysfs_remove_req(struct dca_provider *dca, int slot);
#endif /* DCA_H */