[PATCH] drm/amdgpu: Add sysfs file for VBIOS

[Russell, Kent]

No real reason for sysfs instead of debugfs, I just picked the one that was more familiar with. I can definitely move it to debugfs instead. I will also clean up the commit message per Michel's comments. Thank you!

 Kent

-----Original Message-----
From: Christian König [mailto:deathsimple at vodafone.de] 
Sent: Thursday, August 24, 2017 2:22 AM
To: Russell, Kent; amd-gfx at lists.freedesktop.org
Subject: Re: [PATCH] drm/amdgpu: Add sysfs file for VBIOS

Am 23.08.2017 um 20:12 schrieb Kent Russell:
> This won't change after initialization, so we can add the information 
> when we parse the atombios information. This ensures that we can find 
> out the VBIOS, even when the dmesg buffer fills up, and makes it 
> easier to associate which VBIOS is for which GPU on mGPU 
> configurations. Set the size to 20 characters in case of some weird 
> VBIOS suffix that exceeds the expected 17 character format (3-8-3\0)

Is there any reason that needs to be sysfs? Sounds more like an use case for debugfs.

Christian.

>
> Signed-off-by: Kent Russell <kent.russell at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 23 +++++++++++++++++++++++
>   drivers/gpu/drm/amd/amdgpu/atom.c          |  5 ++++-
>   drivers/gpu/drm/amd/amdgpu/atom.h          |  1 +
>   3 files changed, 28 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c 
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index a1f9424..f40be71 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -888,6 +888,20 @@ static uint32_t cail_ioreg_read(struct card_info *info, uint32_t reg)
>   	return r;
>   }
>   
> +static ssize_t amdgpu_atombios_get_vbios_version(struct device *dev,
> +						 struct device_attribute *attr,
> +						 char *buf)
> +{
> +	struct drm_device *ddev = dev_get_drvdata(dev);
> +	struct amdgpu_device *adev = ddev->dev_private;
> +	struct atom_context *ctx = adev->mode_info.atom_context;
> +
> +	return snprintf(buf, PAGE_SIZE, "%s\n", ctx->vbios_version); }
> +
> +static DEVICE_ATTR(vbios_version, 0444, amdgpu_atombios_get_vbios_version,
> +		   NULL);
> +
>   /**
>    * amdgpu_atombios_fini - free the driver info and callbacks for atombios
>    *
> @@ -907,6 +921,7 @@ static void amdgpu_atombios_fini(struct amdgpu_device *adev)
>   	adev->mode_info.atom_context = NULL;
>   	kfree(adev->mode_info.atom_card_info);
>   	adev->mode_info.atom_card_info = NULL;
> +	device_remove_file(adev->dev, &dev_attr_vbios_version);
>   }
>   
>   /**
> @@ -923,6 +938,7 @@ static int amdgpu_atombios_init(struct amdgpu_device *adev)
>   {
>   	struct card_info *atom_card_info =
>   	    kzalloc(sizeof(struct card_info), GFP_KERNEL);
> +	int ret;
>   
>   	if (!atom_card_info)
>   		return -ENOMEM;
> @@ -959,6 +975,13 @@ static int amdgpu_atombios_init(struct amdgpu_device *adev)
>   		amdgpu_atombios_scratch_regs_init(adev);
>   		amdgpu_atombios_allocate_fb_scratch(adev);
>   	}
> +
> +	ret = device_create_file(adev->dev, &dev_attr_vbios_version);
> +	if (ret) {
> +		DRM_ERROR("Failed to create device file for VBIOS version\n");
> +		return ret;
> +	}
> +
>   	return 0;
>   }
>   
> diff --git a/drivers/gpu/drm/amd/amdgpu/atom.c 
> b/drivers/gpu/drm/amd/amdgpu/atom.c
> index d69aa2e..69500a8 100644
> --- a/drivers/gpu/drm/amd/amdgpu/atom.c
> +++ b/drivers/gpu/drm/amd/amdgpu/atom.c
> @@ -1343,8 +1343,11 @@ struct atom_context *amdgpu_atom_parse(struct card_info *card, void *bios)
>   		idx = 0x80;
>   
>   	str = CSTR(idx);
> -	if (*str != '\0')
> +	if (*str != '\0') {
>   		pr_info("ATOM BIOS: %s\n", str);
> +		strlcpy(ctx->vbios_version, str, sizeof(ctx->vbios_version));
> +	}
> +
>   
>   	return ctx;
>   }
> diff --git a/drivers/gpu/drm/amd/amdgpu/atom.h 
> b/drivers/gpu/drm/amd/amdgpu/atom.h
> index ddd8045..a391709 100644
> --- a/drivers/gpu/drm/amd/amdgpu/atom.h
> +++ b/drivers/gpu/drm/amd/amdgpu/atom.h
> @@ -140,6 +140,7 @@ struct atom_context {
>   	int io_mode;
>   	uint32_t *scratch;
>   	int scratch_size_bytes;
> +	char vbios_version[20];
>   };
>   
>   extern int amdgpu_atom_debug;