Re: [PATCH] drm/meson: add mode selection limits against specific SoC revisions

[Neil Armstrong]

On 21/04/2020 15:59, Daniel Vetter wrote:
> On Tue, Apr 21, 2020 at 03:44:10PM +0200, Neil Armstrong wrote:
>> The Amlogic S805X/Y uses the same die as the S905X, but with more
>> limited graphics capabilities.
>>
>> This adds a soc version detection adding specific limitations on the HDMI
>> mode selections.
>>
>> Here, we limit to HDMI 1.3a max HDMI PHY clock frequency.
>>
>> Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> 
> Just a drive-by, but the code organization between the dw-hdmi bridge and
> the driver looks pretty terribly and really leaky. Can't we do better?
> Either by fixing the dw-hdmi bridge abstraction to actually abstract
> something, or by givin up the dw-hdmi is a bridge and convert it to some
> helper to implement a drm_encoder. Current status just doesn't make too
> much sense to me.


Yep, the encoder part should be moved out of the dw-hdmi glue driver for sure.
I'll a draft something, but it won't really affect this patch.

Neil

> -Daniel
> 
>> ---
>>  drivers/gpu/drm/meson/meson_drv.c     | 29 ++++++++++++++++++++++++++-
>>  drivers/gpu/drm/meson/meson_drv.h     |  6 ++++++
>>  drivers/gpu/drm/meson/meson_dw_hdmi.c |  7 +++++++
>>  3 files changed, 41 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
>> index 6f29fab79952..621f6de0f076 100644
>> --- a/drivers/gpu/drm/meson/meson_drv.c
>> +++ b/drivers/gpu/drm/meson/meson_drv.c
>> @@ -11,6 +11,7 @@
>>  #include <linux/component.h>
>>  #include <linux/module.h>
>>  #include <linux/of_graph.h>
>> +#include <linux/sys_soc.h>
>>  #include <linux/platform_device.h>
>>  #include <linux/soc/amlogic/meson-canvas.h>
>>  
>> @@ -183,6 +184,24 @@ static void meson_remove_framebuffers(void)
>>  	kfree(ap);
>>  }
>>  
>> +struct meson_drm_soc_attr {
>> +	struct meson_drm_soc_limits limits;
>> +	const struct soc_device_attribute *attrs;
>> +};
>> +
>> +static const struct meson_drm_soc_attr meson_drm_soc_attrs[] = {
>> +	/* S805X/S805Y HDMI PLL won't lock for HDMI PHY freq > 1,65GHz */
>> +	{
>> +		.limits = {
>> +			.max_hdmi_phy_freq = 1650000,
>> +		},
>> +		.attrs = (const struct soc_device_attribute []) {
>> +			{ .soc_id = "GXL (S805*)", },
>> +			{ /* sentinel */ },
>> +		}
>> +	},
>> +};
>> +
>>  static int meson_drv_bind_master(struct device *dev, bool has_components)
>>  {
>>  	struct platform_device *pdev = to_platform_device(dev);
>> @@ -191,7 +210,7 @@ static int meson_drv_bind_master(struct device *dev, bool has_components)
>>  	struct drm_device *drm;
>>  	struct resource *res;
>>  	void __iomem *regs;
>> -	int ret;
>> +	int ret, i;
>>  
>>  	/* Checks if an output connector is available */
>>  	if (!meson_vpu_has_available_connectors(dev)) {
>> @@ -281,6 +300,14 @@ static int meson_drv_bind_master(struct device *dev, bool has_components)
>>  	if (ret)
>>  		goto free_drm;
>>  
>> +	/* Assign limits per soc revision/package */
>> +	for (i = 0 ; i < ARRAY_SIZE(meson_drm_soc_attrs) ; ++i) {
>> +		if (soc_device_match(meson_drm_soc_attrs[i].attrs)) {
>> +			priv->limits = &meson_drm_soc_attrs[i].limits;
>> +			break;
>> +		}
>> +	}
>> +
>>  	/* Remove early framebuffers (ie. simplefb) */
>>  	meson_remove_framebuffers();
>>  
>> diff --git a/drivers/gpu/drm/meson/meson_drv.h b/drivers/gpu/drm/meson/meson_drv.h
>> index 04fdf3826643..5b23704a80d6 100644
>> --- a/drivers/gpu/drm/meson/meson_drv.h
>> +++ b/drivers/gpu/drm/meson/meson_drv.h
>> @@ -30,6 +30,10 @@ struct meson_drm_match_data {
>>  	struct meson_afbcd_ops *afbcd_ops;
>>  };
>>  
>> +struct meson_drm_soc_limits {
>> +	unsigned int max_hdmi_phy_freq;
>> +};
>> +
>>  struct meson_drm {
>>  	struct device *dev;
>>  	enum vpu_compatible compat;
>> @@ -48,6 +52,8 @@ struct meson_drm {
>>  	struct drm_plane *primary_plane;
>>  	struct drm_plane *overlay_plane;
>>  
>> +	const struct meson_drm_soc_limits *limits;
>> +
>>  	/* Components Data */
>>  	struct {
>>  		bool osd1_enabled;
>> diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
>> index e8c94915a4fc..dc3d5122475a 100644
>> --- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
>> +++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
>> @@ -695,6 +695,13 @@ dw_hdmi_mode_valid(struct drm_connector *connector,
>>  	dev_dbg(connector->dev->dev, "%s: vclk:%d phy=%d venc=%d hdmi=%d\n",
>>  		__func__, phy_freq, vclk_freq, venc_freq, hdmi_freq);
>>  
>> +	/* Check against soc revision/package limits */
>> +	if (priv->limits) {
>> +		if (priv->limits->max_hdmi_phy_freq &&
>> +		    phy_freq > priv->limits->max_hdmi_phy_freq)
>> +			return MODE_CLOCK_HIGH;
>> +	}
>> +
>>  	return meson_vclk_vic_supported_freq(phy_freq, vclk_freq);
>>  }
>>  
>> -- 
>> 2.22.0
>>
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