linux-kernel - Re: [PATCH 5/9] drm/msm: add headless gpu device (for imx5)

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Date:   Wed, 14 Nov 2018 18:08:31 -0500
From:   Jonathan marek <jonathan@...ek.ca>
To:     freedreno@...ts.freedesktop.org, Rob Clark <robdclark@...il.com>,
        David Airlie <airlied@...ux.ie>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Niklas Cassel <niklas.cassel@...aro.org>,
        Andy Gross <andy.gross@...aro.org>,
        Govind Singh <govinds@...eaurora.org>,
        "open list:DRM DRIVER FOR MSM ADRENO GPU" 
        <linux-arm-msm@...r.kernel.org>,
        "open list:DRM DRIVER FOR MSM ADRENO GPU" 
        <dri-devel@...ts.freedesktop.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 5/9] drm/msm: add headless gpu device (for imx5)

On 11/14/2018 05:47 PM, Jordan Crouse wrote:
> Thanks for  the patch. Perhaps a small blurb here for the commit log to let
> folks know what your intent was.
> 

I will add an explanation. The intent is clear to me from the commit 
message, but perhaps not for everyone.

> On Wed, Nov 14, 2018 at 05:24:12PM -0500, Jonathan Marek wrote:
>> Signed-off-by: Jonathan Marek <jonathan@...ek.ca>
>> ---
>>   drivers/gpu/drm/msm/Kconfig       |  4 ++--
>>   drivers/gpu/drm/msm/msm_debugfs.c |  2 +-
>>   drivers/gpu/drm/msm/msm_drv.c     | 15 +++++++++++----
>>   include/linux/qcom_scm.h          |  3 +++
>>   4 files changed, 17 insertions(+), 7 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..a10cc0298d38 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;
> 
> I don't think you need to set priv->kms, it should come in as NULL. I would
> normally say that you should set kms to NULL when it is declared, but I kind of
> like pointing it out to the user.
> 

It comes as NULL, but initializing it here matches the other cases in 
the switch (at the cost of 12 characters).

>> +		break;
>>   	case KMS_MDP4:
>>   		kms = mdp4_kms_init(ddev);
>>   		priv->kms = kms;
>> @@ -633,7 +637,7 @@ 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 +1319,11 @@ 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 +1348,7 @@ 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 },
>>   	{ .compatible = "qcom,mdp4", .data = (void *)KMS_MDP4 },
>>   	{ .compatible = "qcom,mdss", .data = (void *)KMS_MDP5 },
>>   	{ .compatible = "qcom,sdm845-mdss", .data = (void *)KMS_DPU },
>> diff --git a/include/linux/qcom_scm.h b/include/linux/qcom_scm.h
>> index 06996ad4f2bc..1637385bcc17 100644
>> --- a/include/linux/qcom_scm.h
>> +++ b/include/linux/qcom_scm.h
>> @@ -67,6 +67,9 @@ extern int qcom_scm_iommu_secure_ptbl_init(u64 addr, u32 size, u32 spare);
>>   extern int qcom_scm_io_readl(phys_addr_t addr, unsigned int *val);
>>   extern int qcom_scm_io_writel(phys_addr_t addr, unsigned int val);
>>   #else
>> +
>> +#include <linux/errno.h>
>> +
> 
> This looks like a separate patch, albeit a useful one.
> 

Yes, that isn't part of this patch. Oops.

>>   static inline
>>   int qcom_scm_set_cold_boot_addr(void *entry, const cpumask_t *cpus)
>>   {
> 
> Jordan
> 

Jonathan