drm_memcpy_from_wc() performs fast copy from WC memory type using non-temporal instructions. Now there are two similar implementations of this function. One exists in drm_cache.c as drm_memcpy_from_wc() and another implementation in i915/i915_memcpy.c as i915_memcpy_from_wc(). drm_memcpy_from_wc() was the recent addition through the series https://patchwork.freedesktop.org/patch/436276/?series=90681&rev=6 The goal of this patch series is to change all users of i915_memcpy_from_wc() to drm_memcpy_from_wc() and a have common implementation in drm and eventually remove the copy from i915. Another benefit of using memcpy functions from drm is that drm_memcpy_from_wc() is available for non-x86 architectures. i915_memcpy_from_wc() is implemented only for x86 and prevents building i915 for ARM64. drm_memcpy_from_wc() does fast copy using non-temporal instructions for x86 and for other architectures makes use of memcpy() family of functions as fallback. Another major difference is unlike i915_memcpy_from_wc(), drm_memcpy_from_wc() will not fail if the passed address argument is not alignment to be used with non-temporal load instructions or if the platform lacks support for those instructions (non-temporal load instructions are provided through SSE4.1 instruction set extension). Instead drm_memcpy_from_wc() continues with fallback functions to complete the copy. This relieves the caller from checking the return value of i915_memcpy_from_wc() and explicitly using a fallback. Follow up series will be created to remove the memcpy_from_wc functions from i915 once the dependency is completely removed. v2: Fixed missing check to find if the address is from system memory or io memory and use the right initialization function to construct the iosys_map structure (Review feedback from Lucas) Cc: Jani Nikula <jani.nikula@xxxxxxxxx> Cc: Lucas De Marchi <lucas.demarchi@xxxxxxxxx> Cc: David Airlie <airlied@xxxxxxxx> Cc: Daniel Vetter <daniel@xxxxxxxx> Cc: Chris Wilson <chris.p.wilson@xxxxxxxxx> Cc: Thomas Hellstr_m <thomas.hellstrom@xxxxxxxxxxxxxxx> Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx> Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx> Cc: Nirmoy Das <nirmoy.das@xxxxxxxxx> Balasubramani Vivekanandan (7): drm: Relax alignment constraint for destination address drm: Add drm_memcpy_from_wc() variant which accepts destination address drm/i915: use the memcpy_from_wc call from the drm drm/i915/guc: use the memcpy_from_wc call from the drm drm/i915/selftests: use the memcpy_from_wc call from the drm drm/i915/gt: Avoid direct dereferencing of io memory drm/i915: Avoid dereferencing io mapped memory drivers/gpu/drm/drm_cache.c | 98 +++++++++++++++++-- drivers/gpu/drm/i915/gem/i915_gem_object.c | 6 +- drivers/gpu/drm/i915/gt/selftest_reset.c | 21 ++-- drivers/gpu/drm/i915/gt/uc/intel_guc_log.c | 15 ++- drivers/gpu/drm/i915/i915_gpu_error.c | 45 +++++---- .../drm/i915/selftests/intel_memory_region.c | 41 +++++--- include/drm/drm_cache.h | 3 + 7 files changed, 174 insertions(+), 55 deletions(-) -- 2.25.1
