diff options
| author | Shannon Nelson <shannon.nelson@intel.com> | 2007-10-16 12:27:41 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-16 20:43:09 +0400 |
| commit | 7589670f37736bcc119ebfbd69aafea6d585d1d4 (patch) | |
| tree | 471f90dda6bcbcd59cc857b4f0130922bba88fc4 /include/linux | |
| parent | 3e037454bcfa4b187e8293d2121bd8c0f5a5c31c (diff) | |
| download | linux-7589670f37736bcc119ebfbd69aafea6d585d1d4.tar.xz | |
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>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/dca.h | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/include/linux/dca.h b/include/linux/dca.h new file mode 100644 index 000000000000..83eaecc6f8ab --- /dev/null +++ b/include/linux/dca.h @@ -0,0 +1,47 @@ +#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 */ |