linux-kernel - [PATCH 2/4] drm/msm: rework GEM

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Message-Id: <20181130150050.13762-3-robdclark@gmail.com>
Date:   Fri, 30 Nov 2018 10:00:40 -0500
From:   Rob Clark <robdclark@...il.com>
To:     dri-devel@...ts.freedesktop.org
Cc:     Jordan Crouse <jcrouse@...eaurora.org>,
        Rob Clark <robdclark@...il.com>,
        David Airlie <airlied@...ux.ie>, linux-arm-msm@...r.kernel.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/4] drm/msm: rework GEM_INFO ioctl

Prep work to add a way to get/set the GEM objects debug name.

Signed-off-by: Rob Clark <robdclark@...il.com>
---
 drivers/gpu/drm/msm/msm_drv.c | 25 ++++++++++++++++---------
 include/uapi/drm/msm_drm.h    | 17 ++++++++++++-----
 2 files changed, 28 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index 9f823bf8d312..913f5b3642b5 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -863,21 +863,28 @@ static int msm_ioctl_gem_info(struct drm_device *dev, void *data,
 	struct drm_gem_object *obj;
 	int ret = 0;
 
-	if (args->flags & ~MSM_INFO_FLAGS)
+	switch (args->info) {
+	case MSM_INFO_GET_OFFSET:
+	case MSM_INFO_GET_IOVA:
+		/* value returned as immediate, not pointer, so len==0: */
+		if (args->len)
+			return -EINVAL;
+		break;
+	default:
 		return -EINVAL;
+	}
 
 	obj = drm_gem_object_lookup(file, args->handle);
 	if (!obj)
 		return -ENOENT;
 
-	if (args->flags & MSM_INFO_IOVA) {
-		uint64_t iova;
-
-		ret = msm_ioctl_gem_info_iova(dev, obj, &iova);
-		if (!ret)
-			args->offset = iova;
-	} else {
-		args->offset = msm_gem_mmap_offset(obj);
+	switch (args->info) {
+	case MSM_INFO_GET_OFFSET:
+		args->value = msm_gem_mmap_offset(obj);
+		break;
+	case MSM_INFO_GET_IOVA:
+		ret = msm_ioctl_gem_info_iova(dev, obj, &args->value);
+		break;
 	}
 
 	drm_gem_object_put_unlocked(obj);
diff --git a/include/uapi/drm/msm_drm.h b/include/uapi/drm/msm_drm.h
index 3c3af92c4b3e..bc1757848c7c 100644
--- a/include/uapi/drm/msm_drm.h
+++ b/include/uapi/drm/msm_drm.h
@@ -105,14 +105,21 @@ struct drm_msm_gem_new {
 	__u32 handle;         /* out */
 };
 
-#define MSM_INFO_IOVA	0x01
-
-#define MSM_INFO_FLAGS (MSM_INFO_IOVA)
+/* Get or set GEM buffer info.  The requested value can be passed
+ * directly in 'value', or for data larger than 64b 'value' is a
+ * pointer to userspace buffer, with 'len' specifying the number of
+ * bytes copied into that buffer.  For info returned by pointer,
+ * calling the GEM_INFO ioctl with null 'value' will return the
+ * required buffer size in 'len'
+ */
+#define MSM_INFO_GET_OFFSET	0x00   /* get mmap() offset, returned by value */
+#define MSM_INFO_GET_IOVA	0x01   /* get iova, returned by value */
 
 struct drm_msm_gem_info {
 	__u32 handle;         /* in */
-	__u32 flags;	      /* in - combination of MSM_INFO_* flags */
-	__u64 offset;         /* out, mmap() offset or iova */
+	__u32 info;           /* in - one of MSM_INFO_* */
+	__u64 value;          /* in or out */
+	__u32 len;            /* in or out */
 };
 
 #define MSM_PREP_READ        0x01
-- 
2.19.2