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drm/vc4: Add helpers for pm get/put.

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This makes sure the vc4_reset doesn't hit an obscure race with the
GET_PARAM ioctl, fixes a decrement outside of the lock, and prevents
future code from making mistakes with the weird return value of
pm_runtime_get_sync().

Signed-off-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20190220210343.28157-6-eric@anholt.net
Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
This commit is contained in:
Eric Anholt
2019-02-20 13:03:42 -08:00
parent 13f0ec3417
commit cb74f6ee8e
4 changed files with 49 additions and 28 deletions
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21
drivers/gpu/drm/vc4/vc4_drv.c
View File

@@ -74,28 +74,25 @@ static int vc4_get_param_ioctl(struct drm_device *dev, void *data,
switch (args->param) { switch (args->param) {
case DRM_VC4_PARAM_V3D_IDENT0: case DRM_VC4_PARAM_V3D_IDENT0:
ret = pm_runtime_get_sync(&vc4->v3d->pdev->dev); ret = vc4_v3d_pm_get(vc4);
if (ret < 0) if (ret)
return ret; return ret;
args->value = V3D_READ(V3D_IDENT0); args->value = V3D_READ(V3D_IDENT0);
pm_runtime_mark_last_busy(&vc4->v3d->pdev->dev); vc4_v3d_pm_put(vc4);
pm_runtime_put_autosuspend(&vc4->v3d->pdev->dev);
break; break;
case DRM_VC4_PARAM_V3D_IDENT1: case DRM_VC4_PARAM_V3D_IDENT1:
ret = pm_runtime_get_sync(&vc4->v3d->pdev->dev); ret = vc4_v3d_pm_get(vc4);
if (ret < 0) if (ret)
return ret; return ret;
args->value = V3D_READ(V3D_IDENT1); args->value = V3D_READ(V3D_IDENT1);
pm_runtime_mark_last_busy(&vc4->v3d->pdev->dev); vc4_v3d_pm_put(vc4);
pm_runtime_put_autosuspend(&vc4->v3d->pdev->dev);
break; break;
case DRM_VC4_PARAM_V3D_IDENT2: case DRM_VC4_PARAM_V3D_IDENT2:
ret = pm_runtime_get_sync(&vc4->v3d->pdev->dev); ret = vc4_v3d_pm_get(vc4);
if (ret < 0) if (ret)
return ret; return ret;
args->value = V3D_READ(V3D_IDENT2); args->value = V3D_READ(V3D_IDENT2);
pm_runtime_mark_last_busy(&vc4->v3d->pdev->dev); vc4_v3d_pm_put(vc4);
pm_runtime_put_autosuspend(&vc4->v3d->pdev->dev);
break; break;
case DRM_VC4_PARAM_SUPPORTS_BRANCHES: case DRM_VC4_PARAM_SUPPORTS_BRANCHES:
case DRM_VC4_PARAM_SUPPORTS_ETC1: case DRM_VC4_PARAM_SUPPORTS_ETC1:

2
drivers/gpu/drm/vc4/vc4_drv.h
View File

@@ -815,6 +815,8 @@ extern struct platform_driver vc4_v3d_driver;
int vc4_v3d_debugfs_ident(struct seq_file *m, void *unused); int vc4_v3d_debugfs_ident(struct seq_file *m, void *unused);
int vc4_v3d_debugfs_regs(struct seq_file *m, void *unused); int vc4_v3d_debugfs_regs(struct seq_file *m, void *unused);
int vc4_v3d_get_bin_slot(struct vc4_dev *vc4); int vc4_v3d_get_bin_slot(struct vc4_dev *vc4);
int vc4_v3d_pm_get(struct vc4_dev *vc4);
void vc4_v3d_pm_put(struct vc4_dev *vc4);
/* vc4_validate.c */ /* vc4_validate.c */
int int

17
drivers/gpu/drm/vc4/vc4_gem.c
View File

@@ -964,12 +964,7 @@ vc4_complete_exec(struct drm_device *dev, struct vc4_exec_info *exec)
/* Release the reference we had on the perf monitor. */ /* Release the reference we had on the perf monitor. */
vc4_perfmon_put(exec->perfmon); vc4_perfmon_put(exec->perfmon);
mutex_lock(&vc4->power_lock); vc4_v3d_pm_put(vc4);
if (--vc4->power_refcount == 0) {
pm_runtime_mark_last_busy(&vc4->v3d->pdev->dev);
pm_runtime_put_autosuspend(&vc4->v3d->pdev->dev);
}
mutex_unlock(&vc4->power_lock);
kfree(exec); kfree(exec);
} }
@@ -1143,17 +1138,11 @@ vc4_submit_cl_ioctl(struct drm_device *dev, void *data,
return -ENOMEM; return -ENOMEM;
} }
mutex_lock(&vc4->power_lock); ret = vc4_v3d_pm_get(vc4);
if (vc4->power_refcount++ == 0) { if (ret) {
ret = pm_runtime_get_sync(&vc4->v3d->pdev->dev);
if (ret < 0) {
mutex_unlock(&vc4->power_lock);
vc4->power_refcount--;
kfree(exec); kfree(exec);
return ret; return ret;
} }
}
mutex_unlock(&vc4->power_lock);
exec->args = args; exec->args = args;
INIT_LIST_HEAD(&exec->unref_list); INIT_LIST_HEAD(&exec->unref_list);

33
drivers/gpu/drm/vc4/vc4_v3d.c
View File

@@ -138,6 +138,39 @@ int vc4_v3d_debugfs_ident(struct seq_file *m, void *unused)
} }
#endif /* CONFIG_DEBUG_FS */ #endif /* CONFIG_DEBUG_FS */
/**
* Wraps pm_runtime_get_sync() in a refcount, so that we can reliably
* get the pm_runtime refcount to 0 in vc4_reset().
*/
int
vc4_v3d_pm_get(struct vc4_dev *vc4)
{
mutex_lock(&vc4->power_lock);
if (vc4->power_refcount++ == 0) {
int ret = pm_runtime_get_sync(&vc4->v3d->pdev->dev);
if (ret < 0) {
vc4->power_refcount--;
mutex_unlock(&vc4->power_lock);
return ret;
}
}
mutex_unlock(&vc4->power_lock);
return 0;
}
void
vc4_v3d_pm_put(struct vc4_dev *vc4)
{
mutex_lock(&vc4->power_lock);
if (--vc4->power_refcount == 0) {
pm_runtime_mark_last_busy(&vc4->v3d->pdev->dev);
pm_runtime_put_autosuspend(&vc4->v3d->pdev->dev);
}
mutex_unlock(&vc4->power_lock);
}
static void vc4_v3d_init_hw(struct drm_device *dev) static void vc4_v3d_init_hw(struct drm_device *dev)
{ {
struct vc4_dev *vc4 = to_vc4_dev(dev); struct vc4_dev *vc4 = to_vc4_dev(dev);