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

[Kuehling, Felix]

Debugfs is only accessible by Root. The BIOS version is already reported in the kernel log, which is visible to everyone. So why hide this away in debugfs?

I think Kent's intention is to add VBIOS version reporting to the rocm-smi tool. I'd prefer using a stable interface like sysfs, and one that doesn't require root access in a tool like rocm-smi.

Regards,
  Felix
________________________________________
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> on behalf of Russell, Kent <Kent.Russell at amd.com>
Sent: Thursday, August 24, 2017 9:06:22 AM
To: Alex Deucher
Cc: Christian König; amd-gfx at lists.freedesktop.org
Subject: RE: [PATCH] drm/amdgpu: Add sysfs file for VBIOS

I can definitely add that as well.

 Kent

-----Original Message-----
From: Alex Deucher [mailto:alexdeucher at gmail.com]
Sent: Thursday, August 24, 2017 8:56 AM
To: Russell, Kent
Cc: Christian König; amd-gfx at lists.freedesktop.org
Subject: Re: [PATCH] drm/amdgpu: Add sysfs file for VBIOS

On Thu, Aug 24, 2017 at 5:58 AM, Russell, Kent <Kent.Russell at amd.com> wrote:
> 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!
>

While you are at it, can you expose the vbios binary itself via debugfs?  That's been on by todo list for a while.

Alex

>  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;
>
>
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