Fast copy using non-temporal instructions for x86 currently exists at two locations. One is implemented in i915 driver at i915/i915_memcpy.c and another copy at drm_cache.c. The plan is to remove the duplicate implementation in i915 driver and use the functions from drm_cache.c.
A variant of drm_memcpy_from_wc() is added in drm_cache.c which accepts address as argument instead of iosys_map for destination. It is a very common scenario in i915 to copy from a WC memory type, which may be an io memory or a system memory to a destination address pointing to system memory. To avoid the overhead of creating iosys_map type for the destination, new variant is created to accept the address directly.
Also a new function is exported in drm_cache.c to find if the fast copy is supported by the platform or not. It is required for i915.
Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com Cc: Maxime Ripard mripard@kernel.org Cc: Thomas Zimmermann tzimmermann@suse.de Cc: David Airlie airlied@linux.ie Cc: Daniel Vetter daniel@ffwll.ch Cc: Thomas Hellstr_m thomas.hellstrom@linux.intel.com
Signed-off-by: Balasubramani Vivekanandan balasubramani.vivekanandan@intel.com --- drivers/gpu/drm/drm_cache.c | 54 +++++++++++++++++++++++++++++++++++++ include/drm/drm_cache.h | 3 +++ 2 files changed, 57 insertions(+)
diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c index a21c1350eb09..eb0bcd33665e 100644 --- a/drivers/gpu/drm/drm_cache.c +++ b/drivers/gpu/drm/drm_cache.c @@ -358,6 +358,54 @@ void drm_memcpy_from_wc(struct iosys_map *dst, } EXPORT_SYMBOL(drm_memcpy_from_wc);
+/** + * drm_memcpy_from_wc_vaddr - Perform the fastest available memcpy from a source + * that may be WC. + * @dst: The destination pointer + * @src: The source pointer + * @len: The size of the area to transfer in bytes + * + * Same as drm_memcpy_from_wc except destination is accepted as system memory + * address. Useful in situations where passing destination address as iosys_map + * is simply an overhead and can be avoided. + */ +void drm_memcpy_from_wc_vaddr(void *dst, const struct iosys_map *src, + unsigned long len) +{ + if (WARN_ON(in_interrupt())) { + iosys_map_memcpy_from(dst, src, 0, len); + return; + } + + if (static_branch_likely(&has_movntdqa)) { + __drm_memcpy_from_wc(dst, + src->is_iomem ? + (void const __force *)src->vaddr_iomem : + src->vaddr, + len); + return; + } + + iosys_map_memcpy_from(dst, src, 0, len); +} +EXPORT_SYMBOL(drm_memcpy_from_wc_vaddr); + +/* + * drm_memcpy_fastcopy_supported - Returns if fast copy using non-temporal + * instructions is supported + * + * Returns true if platform has support for fast copying from wc memory type + * using non-temporal instructions. Else false. + */ +bool drm_memcpy_fastcopy_supported(void) +{ + if (static_branch_likely(&has_movntdqa)) + return true; + + return false; +} +EXPORT_SYMBOL(drm_memcpy_fastcopy_supported); + /* * drm_memcpy_init_early - One time initialization of the WC memcpy code */ @@ -382,6 +430,12 @@ void drm_memcpy_from_wc(struct iosys_map *dst, } EXPORT_SYMBOL(drm_memcpy_from_wc);
+bool drm_memcpy_fastcopy_supported(void) +{ + return false; +} +EXPORT_SYMBOL(drm_memcpy_fastcopy_supported); + void drm_memcpy_init_early(void) { } diff --git a/include/drm/drm_cache.h b/include/drm/drm_cache.h index 22deb216b59c..8f48e4dcd7dc 100644 --- a/include/drm/drm_cache.h +++ b/include/drm/drm_cache.h @@ -77,4 +77,7 @@ void drm_memcpy_init_early(void); void drm_memcpy_from_wc(struct iosys_map *dst, const struct iosys_map *src, unsigned long len); +bool drm_memcpy_fastcopy_supported(void); +void drm_memcpy_from_wc_vaddr(void *dst, const struct iosys_map *src, + unsigned long len); #endif