[igt-dev] [PATCH i-g-t 2/6] lib/ioctl_wrapper: Implement __gem_mmap

[Lukasz Kalamarz <lukasz.kalamarz@intel.com>]

Previous implementation of __gem_mmap__cpu and __gem_mmap_wc  only
differ with setting proper flag for caching. This patch implement __gem_mmap
which merge those two functions into one wrapper.
Small documentation modification are add to be in par with new implementation.

Signed-off-by: Lukasz Kalamarz <lukasz.kalamarz@intel.com>
Cc: Michal Winiarski <michal.winiarski@intel.com>
Cc: Katarzyna Dec <katarzyna.dec@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
---
 lib/ioctl_wrappers.c | 96 +++++++++++++++++++++++++++++++-------------
 lib/ioctl_wrappers.h |  1 +
 2 files changed, 68 insertions(+), 29 deletions(-)

diff --git a/lib/ioctl_wrappers.c b/lib/ioctl_wrappers.c
index f71f0e32..87744edc 100644
--- a/lib/ioctl_wrappers.c
+++ b/lib/ioctl_wrappers.c
@@ -736,6 +736,45 @@ bool gem_mmap__has_wc(int fd)
 	return has_wc > 0;
 }
 
+/**
+ * __gem_mmap:
+ * @fd: open i915 drm file descriptor
+ * @handle: gem buffer object handle
+ * @offset: offset in the gem buffer of the mmap arena
+ * @size: size of the mmap arena
+ * @prot: memory protection bits as used by mmap()
+ * @wc: flag marking if we want to set up MMAP_WC flag
+ *
+ * This functions wraps up procedure to establish a memory mapping through
+ * direct cpu access, bypassing the gpu (valid for wc == false). For wc == true
+ * it also bypass cpu caches completely and GTT system agent (i.e. there is no
+ * automatic tiling of the mmapping through the fence registers).
+ *
+ * Returns: A pointer to the created memory mapping, NULL on failure.
+ */
+void *__gem_mmap(int fd, uint32_t handle, uint64_t offset, uint64_t size, unsigned prot, bool wc)
+{
+	struct drm_i915_gem_mmap arg;
+
+	if (wc & !gem_mmap__has_wc(fd)) {
+		errno = ENOSYS;
+		return NULL;
+	}
+
+	memset(&arg, 0, sizeof(arg));
+	arg.handle = handle;
+	arg.offset = offset;
+	arg.size = size;
+	arg.flags = wc ? I915_MMAP_WC : 0;
+	if (igt_ioctl(fd, DRM_IOCTL_I915_GEM_MMAP, &arg))
+		return NULL;
+
+	VG(VALGRIND_MAKE_MEM_DEFINED(from_user_pointer(arg.addr_ptr), arg.size));
+
+	errno = 0;
+	return from_user_pointer(arg.addr_ptr);
+}
+
 /**
  * __gem_mmap__wc:
  * @fd: open i915 drm file descriptor
@@ -753,25 +792,20 @@ bool gem_mmap__has_wc(int fd)
  */
 void *__gem_mmap__wc(int fd, uint32_t handle, uint64_t offset, uint64_t size, unsigned prot)
 {
-	struct drm_i915_gem_mmap arg;
+       struct drm_i915_gem_mmap mmap_arg;
 
-	if (!gem_mmap__has_wc(fd)) {
-		errno = ENOSYS;
-		return NULL;
-	}
+       memset(&mmap_arg, 0, sizeof(mmap_arg));
+       mmap_arg.handle = handle;
+       mmap_arg.offset = offset;
+       mmap_arg.size = size;
+       mmap_arg.flags = I915_MMAP_WC;
+       if (igt_ioctl(fd, DRM_IOCTL_I915_GEM_MMAP, &mmap_arg))
+               return NULL;
 
-	memset(&arg, 0, sizeof(arg));
-	arg.handle = handle;
-	arg.offset = offset;
-	arg.size = size;
-	arg.flags = I915_MMAP_WC;
-	if (igt_ioctl(fd, DRM_IOCTL_I915_GEM_MMAP, &arg))
-		return NULL;
+       VG(VALGRIND_MAKE_MEM_DEFINED(from_user_pointer(mmap_arg.addr_ptr), mmap_arg.size));
 
-	VG(VALGRIND_MAKE_MEM_DEFINED(from_user_pointer(arg.addr_ptr), arg.size));
-
-	errno = 0;
-	return from_user_pointer(arg.addr_ptr);
+       errno = 0;
+       return from_user_pointer(mmap_arg.addr_ptr);
 }
 
 /**
@@ -782,13 +816,16 @@ void *__gem_mmap__wc(int fd, uint32_t handle, uint64_t offset, uint64_t size, un
  * @size: size of the mmap arena
  * @prot: memory protection bits as used by mmap()
  *
- * Like __gem_mmap__wc() except we assert on failure.
+ * This functions wraps up procedure to establish a memory mapping through
+ * direct cpu access, bypassing the gpu and cpu caches completely and also
+ * bypassing the GTT system agent (i.e. there is no automatic tiling of
+ * the mmapping through the fence registers).We assert on failure.
  *
  * Returns: A pointer to the created memory mapping
  */
 void *gem_mmap__wc(int fd, uint32_t handle, uint64_t offset, uint64_t size, unsigned prot)
 {
-	void *ptr = __gem_mmap__wc(fd, handle, offset, size, prot);
+	void *ptr = __gem_mmap(fd, handle, offset, size, prot, true);
 	igt_assert(ptr);
 	return ptr;
 }
@@ -810,17 +847,17 @@ void *__gem_mmap__cpu(int fd, uint32_t handle, uint64_t offset, uint64_t size, u
 {
 	struct drm_i915_gem_mmap mmap_arg;
 
-	memset(&mmap_arg, 0, sizeof(mmap_arg));
-	mmap_arg.handle = handle;
-	mmap_arg.offset = offset;
-	mmap_arg.size = size;
-	if (igt_ioctl(fd, DRM_IOCTL_I915_GEM_MMAP, &mmap_arg))
-		return NULL;
+       memset(&mmap_arg, 0, sizeof(mmap_arg));
+       mmap_arg.handle = handle;
+       mmap_arg.offset = offset;
+       mmap_arg.size = size;
+       if (igt_ioctl(fd, DRM_IOCTL_I915_GEM_MMAP, &mmap_arg))
+               return NULL;
 
-	VG(VALGRIND_MAKE_MEM_DEFINED(from_user_pointer(mmap_arg.addr_ptr), mmap_arg.size));
+       VG(VALGRIND_MAKE_MEM_DEFINED(from_user_pointer(mmap_arg.addr_ptr), mmap_arg.size));
 
-	errno = 0;
-	return from_user_pointer(mmap_arg.addr_ptr);
+       errno = 0;
+       return from_user_pointer(mmap_arg.addr_ptr);
 }
 
 /**
@@ -831,13 +868,14 @@ void *__gem_mmap__cpu(int fd, uint32_t handle, uint64_t offset, uint64_t size, u
  * @size: size of the mmap arena
  * @prot: memory protection bits as used by mmap()
  *
- * Like __gem_mmap__cpu() except we assert on failure.
+ * This functions wraps up procedure to establish a memory mapping through
+ * direct cpu access, bypassing the gpu completely and we assert on failure.
  *
  * Returns: A pointer to the created memory mapping
  */
 void *gem_mmap__cpu(int fd, uint32_t handle, uint64_t offset, uint64_t size, unsigned prot)
 {
-	void *ptr = __gem_mmap__cpu(fd, handle, offset, size, prot);
+	void *ptr = __gem_mmap(fd, handle, offset, size, prot, false);
 	igt_assert(ptr);
 	return ptr;
 }
diff --git a/lib/ioctl_wrappers.h b/lib/ioctl_wrappers.h
index b22b36b0..51e66c08 100644
--- a/lib/ioctl_wrappers.h
+++ b/lib/ioctl_wrappers.h
@@ -97,6 +97,7 @@ void *gem_mmap__wc(int fd, uint32_t handle, uint64_t offset, uint64_t size, unsi
 void *__gem_mmap__gtt(int fd, uint32_t handle, uint64_t size, unsigned prot);
 void *__gem_mmap__cpu(int fd, uint32_t handle, uint64_t offset, uint64_t size, unsigned prot);
 void *__gem_mmap__wc(int fd, uint32_t handle, uint64_t offset, uint64_t size, unsigned prot);
+void *__gem_mmap(int fd, uint32_t handle, uint64_t offset, uint64_t size, unsigned prot, bool wc);
 
 int gem_munmap(void *ptr, uint64_t size);
 
-- 
2.17.2

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