On Wed, Nov 21, 2018 at 8:55 PM Jonathan Marek <jonathan@xxxxxxxx> wrote:
>
> This patch allows using drm/msm without qcom display hardware. This is
> especially useful for iMX5 hardware, which has a a2xx GPU but uses the
> imx-drm driver for display.
>
> Signed-off-by: Jonathan Marek <jonathan@xxxxxxxx>
> ---
> v2: added commit message and removed unnecessary comment
>
> drivers/gpu/drm/msm/Kconfig | 4 ++--
> drivers/gpu/drm/msm/msm_debugfs.c | 2 +-
> drivers/gpu/drm/msm/msm_drv.c | 21 +++++++++++----------
> 3 files changed, 14 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/Kconfig b/drivers/gpu/drm/msm/Kconfig
> index 843a9d40c05e..cf549f1ed403 100644
> --- a/drivers/gpu/drm/msm/Kconfig
> +++ b/drivers/gpu/drm/msm/Kconfig
> @@ -2,7 +2,7 @@
> config DRM_MSM
> tristate "MSM DRM"
> depends on DRM
> - depends on ARCH_QCOM || (ARM && COMPILE_TEST)
> + depends on ARCH_QCOM || SOC_IMX5 || (ARM && COMPILE_TEST)
> depends on OF && COMMON_CLK
> depends on MMU
> select QCOM_MDT_LOADER if ARCH_QCOM
> @@ -11,7 +11,7 @@ config DRM_MSM
> select DRM_PANEL
> select SHMEM
> select TMPFS
> - select QCOM_SCM
> + select QCOM_SCM if ARCH_QCOM
> select WANT_DEV_COREDUMP
> select SND_SOC_HDMI_CODEC if SND_SOC
> select SYNC_FILE
> diff --git a/drivers/gpu/drm/msm/msm_debugfs.c b/drivers/gpu/drm/msm/msm_debugfs.c
> index f0da0d3c8a80..1ca99ca356a4 100644
> --- a/drivers/gpu/drm/msm/msm_debugfs.c
> +++ b/drivers/gpu/drm/msm/msm_debugfs.c
> @@ -235,7 +235,7 @@ int msm_debugfs_init(struct drm_minor *minor)
> debugfs_create_file("gpu", S_IRUSR, minor->debugfs_root,
> dev, &msm_gpu_fops);
>
> - if (priv->kms->funcs->debugfs_init) {
> + if (priv->kms && priv->kms->funcs->debugfs_init) {
> ret = priv->kms->funcs->debugfs_init(priv->kms, minor);
> if (ret)
> return ret;
> diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
> index 9f219e02f3c7..3f35e57202ef 100644
> --- a/drivers/gpu/drm/msm/msm_drv.c
> +++ b/drivers/gpu/drm/msm/msm_drv.c
> @@ -344,6 +344,7 @@ static int msm_drm_uninit(struct device *dev)
> return 0;
> }
>
> +#define KMS_HEADLESS 1
> #define KMS_MDP4 4
> #define KMS_MDP5 5
> #define KMS_DPU 3
> @@ -495,6 +496,9 @@ static int msm_drm_init(struct device *dev, struct drm_driver *drv)
> msm_gem_shrinker_init(ddev);
>
> switch (get_mdp_ver(pdev)) {
> + case KMS_HEADLESS:
> + priv->kms = kms = NULL;
> + break;
> case KMS_MDP4:
> kms = mdp4_kms_init(ddev);
> priv->kms = kms;
> @@ -512,12 +516,6 @@ static int msm_drm_init(struct device *dev, struct drm_driver *drv)
> }
>
> if (IS_ERR(kms)) {
> - /*
> - * NOTE: once we have GPU support, having no kms should not
> - * be considered fatal.. ideally we would still support gpu
> - * and (for example) use dmabuf/prime to share buffers with
> - * imx drm driver on iMX5
> - */
> dev_err(dev, "failed to load kms\n");
> ret = PTR_ERR(kms);
> goto err_msm_uninit;
> @@ -633,7 +631,7 @@ static int msm_drm_init(struct device *dev, struct drm_driver *drv)
> drm_mode_config_reset(ddev);
>
> #ifdef CONFIG_DRM_FBDEV_EMULATION
> - if (fbdev)
> + if (kms && fbdev)
> priv->fbdev = msm_fbdev_init(ddev);
> #endif
>
> @@ -1315,9 +1313,11 @@ static int msm_pdev_probe(struct platform_device *pdev)
> struct component_match *match = NULL;
> int ret;
>
> - ret = add_display_components(&pdev->dev, &match);
> - if (ret)
> - return ret;
> + if (get_mdp_ver(pdev) != KMS_HEADLESS) {
> + ret = add_display_components(&pdev->dev, &match);
> + if (ret)
> + return ret;
> + }
>
> ret = add_gpu_components(&pdev->dev, &match);
> if (ret)
> @@ -1342,6 +1342,7 @@ static int msm_pdev_remove(struct platform_device *pdev)
> }
>
> static const struct of_device_id dt_match[] = {
> + { .compatible = "qcom,adreno-headless", .data = (void *)KMS_HEADLESS },
so, I don't really think we should have a "headless" dt node, because
that doesn't really represent the hw. Maybe instead for the gpu
device node, we could use a different compatible string like:
gpu@xyz {
compatible = "amd,imageon-205.0", "amd,imageon";
...
};
(ie. amd,imageon instead of qcom,adreno)
Then in adreno_bind() (or somewhere around there), if we have the
amd,imageon compat string instead of qcom,adreno, then programatically
create a dummy "headless" device that the toplevel drm driver can bind
to. I think something like this should be possible, and avoid needing
a qcom,adreno-headless node in dt.
BR,
-R
> { .compatible = "qcom,mdp4", .data = (void *)KMS_MDP4 },
> { .compatible = "qcom,mdss", .data = (void *)KMS_MDP5 },
> { .compatible = "qcom,sdm845-mdss", .data = (void *)KMS_DPU },
> --
> 2.17.1
>
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