[PATCH 2/2] drm/vkms: Add PRIME support by converting to Noralf's shmem helpers.

From: Eric Anholt
Date: Tue Nov 27 2018 - 15:38:29 EST

This cuts out a tremendous amount of boilerplate. I've used the PRIME
support now to test V3D rendering on a STB development board with no
KMS driver.

v2: Use the DEFINE_DRM_GEM_SHMEM_FOPS for proper mmap setup.

Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>
Acked-by: Daniel Vetter <daniel.vetter@xxxxxxxx> (v1)
---
drivers/gpu/drm/Kconfig | 1 +
drivers/gpu/drm/vkms/vkms_crc.c | 28 ++--
drivers/gpu/drm/vkms/vkms_drv.c | 28 +---
drivers/gpu/drm/vkms/vkms_drv.h | 22 ----
drivers/gpu/drm/vkms/vkms_gem.c | 212 ++----------------------------
drivers/gpu/drm/vkms/vkms_plane.c | 17 ++-
6 files changed, 43 insertions(+), 265 deletions(-)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 0dedbc040c77..3bdd95f99feb 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -253,6 +253,7 @@ config DRM_VKMS
tristate "Virtual KMS (EXPERIMENTAL)"
depends on DRM
select DRM_KMS_HELPER
+ select DRM_GEM_SHMEM_HELPER
default n
help
Virtual Kernel Mode-Setting (VKMS) is used for testing or for
diff --git a/drivers/gpu/drm/vkms/vkms_crc.c b/drivers/gpu/drm/vkms/vkms_crc.c
index 9d9e8146db90..72d6422fb1a5 100644
--- a/drivers/gpu/drm/vkms/vkms_crc.c
+++ b/drivers/gpu/drm/vkms/vkms_crc.c
@@ -4,6 +4,7 @@
#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>
+#include <drm/drm_gem_shmem_helper.h>

/**
* compute_crc - Compute CRC value on output frame
@@ -91,21 +92,19 @@ static void compose_cursor(struct vkms_crc_data *cursor_crc,
struct vkms_crc_data *primary_crc, void *vaddr_out)
{
struct drm_gem_object *cursor_obj;
- struct vkms_gem_object *cursor_vkms_obj;
+ void *vaddr;

cursor_obj = drm_gem_fb_get_obj(&cursor_crc->fb, 0);
- cursor_vkms_obj = drm_gem_to_vkms_gem(cursor_obj);
+ vaddr = drm_gem_shmem_vmap(cursor_obj);

- mutex_lock(&cursor_vkms_obj->pages_lock);
- if (!cursor_vkms_obj->vaddr) {
+ if (IS_ERR(vaddr)) {
DRM_WARN("cursor plane vaddr is NULL");
- goto out;
+ return;
}

- blend(vaddr_out, cursor_vkms_obj->vaddr, primary_crc, cursor_crc);
+ blend(vaddr_out, vaddr, primary_crc, cursor_crc);

-out:
- mutex_unlock(&cursor_vkms_obj->pages_lock);
+ drm_gem_shmem_vunmap(cursor_obj, vaddr);
}

static uint32_t _vkms_get_crc(struct vkms_crc_data *primary_crc,
@@ -113,8 +112,8 @@ static uint32_t _vkms_get_crc(struct vkms_crc_data *primary_crc,
{
struct drm_framebuffer *fb = &primary_crc->fb;
struct drm_gem_object *gem_obj = drm_gem_fb_get_obj(fb, 0);
- struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(gem_obj);
- void *vaddr_out = kzalloc(vkms_obj->gem.size, GFP_KERNEL);
+ void *vaddr;
+ void *vaddr_out = kzalloc(gem_obj->size, GFP_KERNEL);
u32 crc = 0;

if (!vaddr_out) {
@@ -122,21 +121,20 @@ static uint32_t _vkms_get_crc(struct vkms_crc_data *primary_crc,
return 0;
}

- mutex_lock(&vkms_obj->pages_lock);
- if (WARN_ON(!vkms_obj->vaddr)) {
- mutex_unlock(&vkms_obj->pages_lock);
+ vaddr = drm_gem_shmem_vmap(gem_obj);
+ if (WARN_ON(IS_ERR(vaddr))) {
kfree(vaddr_out);
return crc;
}

- memcpy(vaddr_out, vkms_obj->vaddr, vkms_obj->gem.size);
- mutex_unlock(&vkms_obj->pages_lock);
+ memcpy(vaddr_out, vaddr, gem_obj->size);

if (cursor_crc)
compose_cursor(cursor_crc, primary_crc, vaddr_out);

crc = compute_crc(vaddr_out, primary_crc);

+ drm_gem_shmem_vunmap(gem_obj, vaddr);
kfree(vaddr_out);

return crc;
diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
index 83087877565c..18f145f0f4db 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.c
+++ b/drivers/gpu/drm/vkms/vkms_drv.c
@@ -19,6 +19,7 @@
#include <drm/drm_crtc_helper.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>
+#include <drm/drm_gem_shmem_helper.h>
#include <drm/drm_fb_helper.h>
#include "vkms_drv.h"

@@ -34,23 +35,7 @@ bool enable_cursor;
module_param_named(enable_cursor, enable_cursor, bool, 0444);
MODULE_PARM_DESC(enable_cursor, "Enable/Disable cursor support");

-static const struct file_operations vkms_driver_fops = {
- .owner = THIS_MODULE,
- .open = drm_open,
- .mmap = drm_gem_mmap,
- .unlocked_ioctl = drm_ioctl,
- .compat_ioctl = drm_compat_ioctl,
- .poll = drm_poll,
- .read = drm_read,
- .llseek = no_llseek,
- .release = drm_release,
-};
-
-static const struct vm_operations_struct vkms_gem_vm_ops = {
- .fault = vkms_gem_fault,
- .open = drm_gem_vm_open,
- .close = drm_gem_vm_close,
-};
+DEFINE_DRM_GEM_SHMEM_FOPS(vkms_driver_fops);

static void vkms_release(struct drm_device *dev)
{
@@ -64,12 +49,13 @@ static void vkms_release(struct drm_device *dev)
}

static struct drm_driver vkms_driver = {
- .driver_features = DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM,
+ .driver_features = (DRIVER_MODESET |
+ DRIVER_ATOMIC |
+ DRIVER_GEM |
+ DRIVER_PRIME),
.release = vkms_release,
.fops = &vkms_driver_fops,
- .dumb_create = vkms_dumb_create,
- .gem_vm_ops = &vkms_gem_vm_ops,
- .gem_free_object_unlocked = vkms_gem_free_object,
+ DRM_GEM_SHMEM_DRIVER_OPS,
.get_vblank_timestamp = vkms_get_vblank_timestamp,

.name = DRIVER_NAME,
diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index e4469cd3d254..3faf49f43feb 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -80,23 +80,12 @@ struct vkms_device {
struct vkms_output output;
};

-struct vkms_gem_object {
- struct drm_gem_object gem;
- struct mutex pages_lock; /* Page lock used in page fault handler */
- struct page **pages;
- unsigned int vmap_count;
- void *vaddr;
-};
-
#define drm_crtc_to_vkms_output(target) \
container_of(target, struct vkms_output, crtc)

#define drm_device_to_vkms_device(target) \
container_of(target, struct vkms_device, drm)

-#define drm_gem_to_vkms_gem(target)\
- container_of(target, struct vkms_gem_object, gem)
-
#define to_vkms_crtc_state(target)\
container_of(target, struct vkms_crtc_state, base)

@@ -122,17 +111,6 @@ struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
u32 *handle,
u64 size);

-vm_fault_t vkms_gem_fault(struct vm_fault *vmf);
-
-int vkms_dumb_create(struct drm_file *file, struct drm_device *dev,
- struct drm_mode_create_dumb *args);
-
-void vkms_gem_free_object(struct drm_gem_object *obj);
-
-int vkms_gem_vmap(struct drm_gem_object *obj);
-
-void vkms_gem_vunmap(struct drm_gem_object *obj);
-
/* CRC Support */
int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name);
int vkms_verify_crc_source(struct drm_crtc *crtc, const char *source_name,
diff --git a/drivers/gpu/drm/vkms/vkms_gem.c b/drivers/gpu/drm/vkms/vkms_gem.c
index 80311daed47a..11f52aa4e732 100644
--- a/drivers/gpu/drm/vkms/vkms_gem.c
+++ b/drivers/gpu/drm/vkms/vkms_gem.c
@@ -7,222 +7,34 @@
*/

#include <linux/shmem_fs.h>
+#include <drm/drm_gem_shmem_helper.h>

#include "vkms_drv.h"

-static struct vkms_gem_object *__vkms_gem_create(struct drm_device *dev,
- u64 size)
-{
- struct vkms_gem_object *obj;
- int ret;
-
- obj = kzalloc(sizeof(*obj), GFP_KERNEL);
- if (!obj)
- return ERR_PTR(-ENOMEM);
-
- size = roundup(size, PAGE_SIZE);
- ret = drm_gem_object_init(dev, &obj->gem, size);
- if (ret) {
- kfree(obj);
- return ERR_PTR(ret);
- }
-
- mutex_init(&obj->pages_lock);
-
- return obj;
-}
-
-void vkms_gem_free_object(struct drm_gem_object *obj)
-{
- struct vkms_gem_object *gem = container_of(obj, struct vkms_gem_object,
- gem);
-
- WARN_ON(gem->pages);
- WARN_ON(gem->vaddr);
-
- mutex_destroy(&gem->pages_lock);
- drm_gem_object_release(obj);
- kfree(gem);
-}
-
-vm_fault_t vkms_gem_fault(struct vm_fault *vmf)
-{
- struct vm_area_struct *vma = vmf->vma;
- struct vkms_gem_object *obj = vma->vm_private_data;
- unsigned long vaddr = vmf->address;
- pgoff_t page_offset;
- loff_t num_pages;
- vm_fault_t ret = VM_FAULT_SIGBUS;
-
- page_offset = (vaddr - vma->vm_start) >> PAGE_SHIFT;
- num_pages = DIV_ROUND_UP(obj->gem.size, PAGE_SIZE);
-
- if (page_offset > num_pages)
- return VM_FAULT_SIGBUS;
-
- mutex_lock(&obj->pages_lock);
- if (obj->pages) {
- get_page(obj->pages[page_offset]);
- vmf->page = obj->pages[page_offset];
- ret = 0;
- }
- mutex_unlock(&obj->pages_lock);
- if (ret) {
- struct page *page;
- struct address_space *mapping;
-
- mapping = file_inode(obj->gem.filp)->i_mapping;
- page = shmem_read_mapping_page(mapping, page_offset);
-
- if (!IS_ERR(page)) {
- vmf->page = page;
- ret = 0;
- } else {
- switch (PTR_ERR(page)) {
- case -ENOSPC:
- case -ENOMEM:
- ret = VM_FAULT_OOM;
- break;
- case -EBUSY:
- ret = VM_FAULT_RETRY;
- break;
- case -EFAULT:
- case -EINVAL:
- ret = VM_FAULT_SIGBUS;
- break;
- default:
- WARN_ON(PTR_ERR(page));
- ret = VM_FAULT_SIGBUS;
- break;
- }
- }
- }
- return ret;
-}
-
struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
struct drm_file *file,
u32 *handle,
u64 size)
{
- struct vkms_gem_object *obj;
+ struct drm_gem_shmem_object *obj;
int ret;

if (!file || !dev || !handle)
return ERR_PTR(-EINVAL);

- obj = __vkms_gem_create(dev, size);
+ obj = drm_gem_shmem_create(dev, size);
if (IS_ERR(obj))
return ERR_CAST(obj);

- ret = drm_gem_handle_create(file, &obj->gem, handle);
- drm_gem_object_put_unlocked(&obj->gem);
- if (ret) {
- drm_gem_object_release(&obj->gem);
- kfree(obj);
+ /*
+ * Allocate an id of idr table where the obj is registered
+ * and handle has the id what user can see.
+ */
+ ret = drm_gem_handle_create(file, &obj->base, handle);
+ /* drop reference from allocate - handle holds it now. */
+ drm_gem_object_put_unlocked(&obj->base);
+ if (ret)
return ERR_PTR(ret);
- }
-
- return &obj->gem;
-}
-
-int vkms_dumb_create(struct drm_file *file, struct drm_device *dev,
- struct drm_mode_create_dumb *args)
-{
- struct drm_gem_object *gem_obj;
- u64 pitch, size;
-
- if (!args || !dev || !file)
- return -EINVAL;
-
- pitch = args->width * DIV_ROUND_UP(args->bpp, 8);
- size = pitch * args->height;
-
- if (!size)
- return -EINVAL;
-
- gem_obj = vkms_gem_create(dev, file, &args->handle, size);
- if (IS_ERR(gem_obj))
- return PTR_ERR(gem_obj);
-
- args->size = gem_obj->size;
- args->pitch = pitch;
-
- DRM_DEBUG_DRIVER("Created object of size %lld\n", size);
-
- return 0;
-}
-
-static struct page **_get_pages(struct vkms_gem_object *vkms_obj)
-{
- struct drm_gem_object *gem_obj = &vkms_obj->gem;
-
- if (!vkms_obj->pages) {
- struct page **pages = drm_gem_get_pages(gem_obj);
-
- if (IS_ERR(pages))
- return pages;
-
- if (cmpxchg(&vkms_obj->pages, NULL, pages))
- drm_gem_put_pages(gem_obj, pages, false, true);
- }
-
- return vkms_obj->pages;
-}
-
-void vkms_gem_vunmap(struct drm_gem_object *obj)
-{
- struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(obj);
-
- mutex_lock(&vkms_obj->pages_lock);
- if (vkms_obj->vmap_count < 1) {
- WARN_ON(vkms_obj->vaddr);
- WARN_ON(vkms_obj->pages);
- mutex_unlock(&vkms_obj->pages_lock);
- return;
- }
-
- vkms_obj->vmap_count--;
-
- if (vkms_obj->vmap_count == 0) {
- vunmap(vkms_obj->vaddr);
- vkms_obj->vaddr = NULL;
- drm_gem_put_pages(obj, vkms_obj->pages, false, true);
- vkms_obj->pages = NULL;
- }
-
- mutex_unlock(&vkms_obj->pages_lock);
-}
-
-int vkms_gem_vmap(struct drm_gem_object *obj)
-{
- struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(obj);
- int ret = 0;
-
- mutex_lock(&vkms_obj->pages_lock);
-
- if (!vkms_obj->vaddr) {
- unsigned int n_pages = obj->size >> PAGE_SHIFT;
- struct page **pages = _get_pages(vkms_obj);
-
- if (IS_ERR(pages)) {
- ret = PTR_ERR(pages);
- goto out;
- }
-
- vkms_obj->vaddr = vmap(pages, n_pages, VM_MAP, PAGE_KERNEL);
- if (!vkms_obj->vaddr)
- goto err_vmap;
- }
-
- vkms_obj->vmap_count++;
- goto out;

-err_vmap:
- ret = -ENOMEM;
- drm_gem_put_pages(obj, vkms_obj->pages, false, true);
- vkms_obj->pages = NULL;
-out:
- mutex_unlock(&vkms_obj->pages_lock);
- return ret;
+ return &obj->base;
}
diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index 7041007396ae..29e6e870d7ac 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -11,6 +11,7 @@
#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>
+#include <drm/drm_gem_shmem_helper.h>

static struct drm_plane_state *
vkms_plane_duplicate_state(struct drm_plane *plane)
@@ -138,17 +139,17 @@ static int vkms_prepare_fb(struct drm_plane *plane,
struct drm_plane_state *state)
{
struct drm_gem_object *gem_obj;
- struct vkms_gem_object *vkms_obj;
- int ret;
+ void *map;

if (!state->fb)
return 0;

gem_obj = drm_gem_fb_get_obj(state->fb, 0);
- vkms_obj = drm_gem_to_vkms_gem(gem_obj);
- ret = vkms_gem_vmap(gem_obj);
- if (ret)
- DRM_ERROR("vmap failed: %d\n", ret);
+ map = drm_gem_shmem_vmap(gem_obj);
+ if (IS_ERR(map)) {
+ DRM_ERROR("vmap failed: %ld\n", PTR_ERR(map));
+ return PTR_ERR(map);
+ }

return drm_gem_fb_prepare_fb(plane, state);
}
@@ -157,12 +158,14 @@ static void vkms_cleanup_fb(struct drm_plane *plane,
struct drm_plane_state *old_state)
{
struct drm_gem_object *gem_obj;
+ struct drm_gem_shmem_object *shmem_obj;

if (!old_state->fb)
return;

gem_obj = drm_gem_fb_get_obj(old_state->fb, 0);
- vkms_gem_vunmap(gem_obj);
+ shmem_obj = to_drm_gem_shmem_obj(gem_obj);
+ drm_gem_shmem_vunmap(gem_obj, shmem_obj->vaddr);
}

static const struct drm_plane_helper_funcs vkms_primary_helper_funcs = {
--
2.20.0.rc1