drivers/gpu/drm/i915/i915_memcpy.h

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/i915/i915_memcpy.h

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/i915/i915_memcpy.h
Extension
.h
Size
1194 bytes
Lines
35
Domain
Driver Families
Bucket
drivers/gpu
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef __I915_MEMCPY_H__
#define __I915_MEMCPY_H__

#include <linux/types.h>

struct drm_i915_private;

void i915_memcpy_init_early(struct drm_i915_private *i915);

bool i915_memcpy_from_wc(void *dst, const void *src, unsigned long len);
void i915_unaligned_memcpy_from_wc(void *dst, const void *src, unsigned long len);

/* The movntdqa instructions used for memcpy-from-wc require 16-byte alignment,
 * as well as SSE4.1 support. i915_memcpy_from_wc() will report if it cannot
 * perform the operation. To check beforehand, pass in the parameters to
 * to i915_can_memcpy_from_wc() - since we only care about the low 4 bits,
 * you only need to pass in the minor offsets, page-aligned pointers are
 * always valid.
 *
 * For just checking for SSE4.1, in the foreknowledge that the future use
 * will be correctly aligned, just use i915_has_memcpy_from_wc().
 */
#define i915_can_memcpy_from_wc(dst, src, len) \
	i915_memcpy_from_wc((void *)((unsigned long)(dst) | (unsigned long)(src) | (len)), NULL, 0)

#define i915_has_memcpy_from_wc() \
	i915_memcpy_from_wc(NULL, NULL, 0)

#endif /* __I915_MEMCPY_H__ */

Annotation

Implementation Notes