RE: [PATCH v5 3/3] media: vsp1: Add support for RZ/G2L VSPD

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Hi Laurent,

Thanks for the feedback.

> Subject: Re: [PATCH v5 3/3] media: vsp1: Add support for RZ/G2L VSPD
> 
> Hi Biju,
> 
> Thank you for the patch.
> 
> On Sat, Mar 12, 2022 at 08:42:05AM +0000, Biju Das wrote:
> > The RZ/G2L VSPD provides a single VSPD instance. It has the following
> > sub modules MAU, CTU, RPF, DPR, LUT, BRS, WPF and LIF.
> >
> > The VSPD block on RZ/G2L does not have a version register, so added a
> > new compatible string "renesas,rzg2l-vsp2" with a data pointer
> > containing the info structure. Also the reset line is shared with the DU
> module.
> >
> > Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> > Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> > Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> > ---
> > v4->v5:
> >  * Fixed typo VI6_IP_VERSION_MODEL_MASK->VI6_IP_VERSION_MASK
> >  * To be consistent with other SoC's, introduced VI6_IP_VERSION_SOC_G2L
> >    for RZ/G2L SoC's.
> > v3->v4:
> >  * Added Rb tag from Geert
> >  * Add switch() for LIF0 buffer attribute handling for RZ/G2L and V3M
> > v2->v3:
> >  * Fixed version comparison in vsp1_lookup()
> > v1->v2:
> >  * Changed the compatible from vsp2-rzg2l->rzg2l-vsp2
> >  * Added standalone device info for rzg2l-vsp2.
> >  * Added vsp1_lookup helper function.
> >  * Updated comments for LIF0 buffer attribute register
> >  * Used last ID for rzg2l-vsp2.
> > RFC->v1:
> >  * Used data pointer containing info structure to retrieve version
> > information
> > RFC:
> >  *
> > ---
> >  drivers/media/platform/vsp1/vsp1_drv.c  | 44
> > +++++++++++++++++++------  drivers/media/platform/vsp1/vsp1_lif.c  |
> > 16 +++++----  drivers/media/platform/vsp1/vsp1_regs.h |  4 +++
> >  3 files changed, 48 insertions(+), 16 deletions(-)
> >
> > diff --git a/drivers/media/platform/vsp1/vsp1_drv.c
> > b/drivers/media/platform/vsp1/vsp1_drv.c
> > index 699d7d985df4..4eef6d525eda 100644
> > --- a/drivers/media/platform/vsp1/vsp1_drv.c
> > +++ b/drivers/media/platform/vsp1/vsp1_drv.c
> > @@ -811,11 +811,37 @@ static const struct vsp1_device_info
> vsp1_device_infos[] = {
> >  	},
> >  };
> >
> > +static const struct vsp1_device_info rzg2l_vsp2_device_info = {
> > +		.version = VI6_IP_VERSION_MODEL_VSPD_RZG2L,
> > +		.model = "VSP2-D",
> > +		.gen = 3,
> > +		.features = VSP1_HAS_BRS | VSP1_HAS_WPF_VFLIP |
> VSP1_HAS_EXT_DL,
> > +		.lif_count = 1,
> > +		.rpf_count = 2,
> > +		.wpf_count = 1,
> 
> One tab is enough for indentation.

Agreed. Will fix this.

> 
> > +};
> > +
> > +static const struct vsp1_device_info *vsp1_lookup(struct vsp1_device
> *vsp1,
> > +						  u32 version)
> 
> Let's call this vsp1_lookup_info(), just "lookup" is a bit vague.

OK.

> 
> > +{
> > +	unsigned int i;
> > +
> > +	for (i = 0; i < ARRAY_SIZE(vsp1_device_infos); ++i) {
> > +		if ((version & VI6_IP_VERSION_MODEL_MASK) ==
> > +		    vsp1_device_infos[i].version) {
> > +			vsp1->info = &vsp1_device_infos[i];
> > +			break;
> > +		}
> > +	}
> > +
> > +	return vsp1->info;
> 
> Could we move all the info logic in this function ? Something like this:

OK for me, If there is no objections.

What about using vsp1->version instead of local variable version,
So that in case of synthetic version, we can override MSB's with
0xFFFE (Please see below)

> 
> 	const struct vsp1_device_info *info;
> 	unsigned int i;
> 	u32 version;

Here Remove the local variable version and instead use vsp1->version.
> 
> 	/*
> 	 * Try the info stored in match data first for devices that don't
> have
> 	 * a version register.
> 	 */
> 	info = of_device_get_match_data(vsp1->dev);
> 	if (info)
> 		return info;
> 
> 	version = vsp1_read(vsp1, VI6_IP_VERSION);
	

vsp1->version = vsp1_read(vsp1, VI6_IP_VERSION);

> 
> 	for (i = 0; i < ARRAY_SIZE(vsp1_device_infos); ++i) {
> 		info = &vsp1_device_infos[i];
> 
> 		if ((version & VI6_IP_VERSION_MODEL_MASK) == info->version);
> 			return info;
> 	}
> 
> 	dev_err(vsp1->dev, "unsupported IP version 0x%08x\n", version);
> 
> 	return NULL;
> 
> > +}
> > +
> >  static int vsp1_probe(struct platform_device *pdev)  {
> >  	struct vsp1_device *vsp1;
> >  	struct device_node *fcp_node;
> > -	unsigned int i;
> > +	u32 version;
> >  	int ret;
> >  	int irq;
> >
> > @@ -871,24 +897,21 @@ static int vsp1_probe(struct platform_device
> *pdev)
> >  	if (ret < 0)
> >  		goto done;
> >
> > -	vsp1->version = vsp1_read(vsp1, VI6_IP_VERSION);
> > -
> > -	for (i = 0; i < ARRAY_SIZE(vsp1_device_infos); ++i) {
> > -		if ((vsp1->version & VI6_IP_VERSION_MODEL_MASK) ==
> > -		    vsp1_device_infos[i].version) {
> > -			vsp1->info = &vsp1_device_infos[i];
> > -			break;
> > -		}
> > +	vsp1->info = of_device_get_match_data(&pdev->dev);
> > +	if (!vsp1->info) {
> > +		version = vsp1_read(vsp1, VI6_IP_VERSION);
> > +		vsp1->info = vsp1_lookup(vsp1, version);
> >  	}
> >
> >  	if (!vsp1->info) {
> >  		dev_err(&pdev->dev, "unsupported IP version 0x%08x\n",
> > -			vsp1->version);
> > +			version);
> >  		vsp1_device_put(vsp1);
> >  		ret = -ENXIO;
> >  		goto done;
> >  	}
> >
> > +	vsp1->version = vsp1->info->version;
> 
> And here you would have
> 
> 	vsp1->info = vsp1_lookup_info(vsp1);
> 	if (!vsp1->info) {
> 		ret = -ENXIO;
> 		goto done;
> 	}
> 
> 	vsp1->version = vsp1->info->version;

Here some thing like
(vsp1->version & 0x0101)--> real hw version
Else
Synthetic version {
vsp1->version = (0xFFFE0000)| vsp1->info->version | VI6_IP_VERSION_SOC_RZG2L;
}

so that it won't break user space as mentioned below.

> 
> A subsequent patch could even drop the version field from vsp1_device and
> use vsp1->info->version instead of vsp1->version.

May be it is not needed ??

> 
> There's however a small issue. The version number is exposed to userspace.
> Currently it's a full 32-bit value with the 16 MSBs being
> 0x0101 for all VSP versions, and the 16 LSBs identifying the VSP model and
> SoC. With this patch, the version number is retrieved from the info
> structure, and the 16 MSBs will thus be 0x0000. This may cause issues in
> userspace.
> 
> One option would be to set the 16 MSBs in vsp1_device_info.version (using
> a new macro added to vsp1_regs.h, I'm not sure how to call it as it's not
> clear what 0x0101 represents, if it's meant to identify the fact that the
> device is a VSP, maybe VI6_IP_VERSION_VSP ?).

HW document doesn't mention about what 0x0101 represents for MSBs? 
What about VI6_IP_VERSION_VSP_HW_MSB to differentiate HW version.

> 
> >  	dev_dbg(&pdev->dev, "IP version 0x%08x\n", vsp1->version);
> >
> >  	/*
> > @@ -940,6 +963,7 @@ static int vsp1_remove(struct platform_device
> > *pdev)  static const struct of_device_id vsp1_of_match[] = {
> >  	{ .compatible = "renesas,vsp1" },
> >  	{ .compatible = "renesas,vsp2" },
> > +	{ .compatible = "renesas,rzg2l-vsp2", .data =
> > +&rzg2l_vsp2_device_info },
> >  	{ },
> >  };
> >  MODULE_DEVICE_TABLE(of, vsp1_of_match); diff --git
> > a/drivers/media/platform/vsp1/vsp1_lif.c
> > b/drivers/media/platform/vsp1/vsp1_lif.c
> > index 6a6857ac9327..35abed29f269 100644
> > --- a/drivers/media/platform/vsp1/vsp1_lif.c
> > +++ b/drivers/media/platform/vsp1/vsp1_lif.c
> > @@ -107,6 +107,7 @@ static void lif_configure_stream(struct
> > vsp1_entity *entity,
> >
> >  	case VI6_IP_VERSION_MODEL_VSPDL_GEN3:
> >  	case VI6_IP_VERSION_MODEL_VSPD_V3:
> > +	case VI6_IP_VERSION_MODEL_VSPD_RZG2L:
> >  		hbth = 0;
> >  		obth = 1500;
> >  		lbth = 0;
> > @@ -130,16 +131,19 @@ static void lif_configure_stream(struct
> vsp1_entity *entity,
> >  			VI6_LIF_CTRL_REQSEL | VI6_LIF_CTRL_LIF_EN);
> >
> >  	/*
> > -	 * On R-Car V3M the LIF0 buffer attribute register has to be set to
> a
> > -	 * non-default value to guarantee proper operation (otherwise
> artifacts
> > -	 * may appear on the output). The value required by the manual is
> not
> > -	 * explained but is likely a buffer size or threshold.
> > +	 * On R-Car V3M and RZ/G2L the LIF0 buffer attribute register has to
> be
> > +	 * set to a non-default value to guarantee proper operation
> (otherwise
> > +	 * artifacts may appear on the output). The value required by the
> > +	 * manual is not explained but is likely a buffer size or threshold.
> >  	 */
> > -	if ((entity->vsp1->version & VI6_IP_VERSION_MASK) ==
> > -	    (VI6_IP_VERSION_MODEL_VSPD_V3 | VI6_IP_VERSION_SOC_V3M))
> > +	switch (entity->vsp1->version & VI6_IP_VERSION_MASK) {
> > +	case (VI6_IP_VERSION_MODEL_VSPD_V3 | VI6_IP_VERSION_SOC_V3M):
> > +	case (VI6_IP_VERSION_MODEL_VSPD_RZG2L | VI6_IP_VERSION_SOC_G2L):
> >  		vsp1_lif_write(lif, dlb, VI6_LIF_LBA,
> >  			       VI6_LIF_LBA_LBA0 |
> >  			       (1536 << VI6_LIF_LBA_LBA1_SHIFT));
> > +		break;
> > +	}
> >  }
> >
> >  static const struct vsp1_entity_operations lif_entity_ops = { diff
> > --git a/drivers/media/platform/vsp1/vsp1_regs.h
> > b/drivers/media/platform/vsp1/vsp1_regs.h
> > index fae7286eb01e..3963119eecc5 100644
> > --- a/drivers/media/platform/vsp1/vsp1_regs.h
> > +++ b/drivers/media/platform/vsp1/vsp1_regs.h
> > @@ -767,8 +767,12 @@
> >  #define VI6_IP_VERSION_MODEL_VSPDL_GEN3	(0x19 << 8)
> >  #define VI6_IP_VERSION_MODEL_VSPBS_GEN3	(0x1a << 8)
> >  #define VI6_IP_VERSION_MODEL_VSPD_V3U	(0x1c << 8)
> > +/* RZ/G2L SoC's have no version register, So using last ID for the
> version */
> > +#define VI6_IP_VERSION_MODEL_VSPD_RZG2L	(0xff << 8)
> >
> >  #define VI6_IP_VERSION_SOC_MASK		(0xff << 0)
> > +/* RZ/G2L SoC's have no version register, So use '0' for SoC
> Identification */
> > +#define VI6_IP_VERSION_SOC_G2L		(0x00 << 0)
> 
> Hmmmm... I wonder how we can make sure here that no future SoCs will use
> 0xff or 0x00. Especially from a userspace point of view, The resulting
> version number will be 0x0000ff00, I'm not sure it will let us have a nice
> versioning scheme if we have to extend this to new SoCs that have
> different VSPs also lacking a version register.
> 
> I wonder if we could possibly use the 16 MSBs to differentiate between
> real hardware versions and synthetic versions. For instance, we could set
> the MSBs to 0xfffe (unlikely to be used by real hardware), and then we
> could allocate version numbers for the 16 LSBs freely, starting numbering
> at 0x01 (or maybe a higher value, such as 0x80 ?) for the model and SoC
> identifiers.
> 
> What does everybody think ?

I am ok for synthetic version of "0xfffe8000" for RZ/G2L, if there is 
no objections and add 0xFFFE in the current 

VI6_IP_VERSION_VSP_SW_MSB		(0xFFFE << 16)
VI6_IP_VERSION_MODEL_VSPD_RZG2L	(0x80 << 8)
VI6_IP_VERSION_SOC_RZG2L		(0x00 << 0)

We could directly use "entity->vsp1->version" instead of 
'entity->vsp1->version & VI6_IP_VERSION_MASK'
for the switch() ('switch (entity->vsp1->version & VI6_IP_VERSION_MASK)') as

switch(entity->vsp1->version) has already differentiation between real and 
synthetic version.

VI6_IP_VERSION_V3M ((vsp1->version & VI6_IP_VERSION_VSP_HW_MSB) | VI6_IP_VERSION_MODEL_VSPD_V3 | VI6_IP_VERSION_SOC_V3M)
VI6_IP_VERSION_RZG2L ((vsp1->version & VI6_IP_VERSION_VSP_SW_MSB) | IP_VERSION_MODEL_VSPD_RZG2L | VI6_IP_VERSION_SOC_RZG2L)

Cheers,
Biju


> 
> >  #define VI6_IP_VERSION_SOC_H2		(0x01 << 0)
> >  #define VI6_IP_VERSION_SOC_V2H		(0x01 << 0)
> >  #define VI6_IP_VERSION_SOC_V3M		(0x01 << 0)
> >
> 
> --
> Regards,
> 
> Laurent Pinchart




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