[PATCH v6 1/2] drm/amdgpu: add debugfs for reset registers list

Lazar, Lijo lijo.lazar at amd.com
Wed Feb 16 13:17:44 UTC 2022



On 2/16/2022 4:39 PM, Somalapuram, Amaranath wrote:
> 
> On 2/16/2022 4:13 PM, Lazar, Lijo wrote:
>>
>>
>> On 2/16/2022 4:04 PM, Somalapuram, Amaranath wrote:
>>>
>>> On 2/16/2022 3:45 PM, Lazar, Lijo wrote:
>>>>
>>>>
>>>> On 2/16/2022 3:19 PM, Somalapuram Amaranath wrote:
>>>>> List of register populated for dump collection during the GPU reset.
>>>>>
>>>>> Signed-off-by: Somalapuram Amaranath <Amaranath.Somalapuram at amd.com>
>>>>> ---
>>>>>   drivers/gpu/drm/amd/amdgpu/amdgpu.h         |  5 ++
>>>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 95 
>>>>> +++++++++++++++++++++
>>>>>   2 files changed, 100 insertions(+)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h 
>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>>>>> index b85b67a88a3d..57965316873b 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>>>>> @@ -1097,6 +1097,11 @@ struct amdgpu_device {
>>>>>         struct amdgpu_reset_control     *reset_cntl;
>>>>>       uint32_t ip_versions[HW_ID_MAX][HWIP_MAX_INSTANCE];
>>>>> +
>>>>> +    /* reset dump register */
>>>>> +    uint32_t            *reset_dump_reg_list;
>>>>> +    int                             n_regs;
>>>>> +    struct mutex            reset_dump_mutex;
>>>>>   };
>>>>>     static inline struct amdgpu_device *drm_to_adev(struct 
>>>>> drm_device *ddev)
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c 
>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
>>>>> index 164d6a9e9fbb..faf985c7cb93 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
>>>>> @@ -1609,6 +1609,98 @@ DEFINE_DEBUGFS_ATTRIBUTE(fops_ib_preempt, NULL,
>>>>>   DEFINE_DEBUGFS_ATTRIBUTE(fops_sclk_set, NULL,
>>>>>               amdgpu_debugfs_sclk_set, "%llu\n");
>>>>>   +static ssize_t amdgpu_reset_dump_register_list_read(struct file *f,
>>>>> +                char __user *buf, size_t size, loff_t *pos)
>>>>> +{
>>>>> +    struct amdgpu_device *adev = (struct amdgpu_device 
>>>>> *)file_inode(f)->i_private;
>>>>> +    char reg_offset[11];
>>>>> +    int i, r, len = 0;
>>>>> +
>>>>> +    if (*pos)
>>>>> +        return 0;
>>>>> +
>>>>> +    if (adev->n_regs == 0)
>>>>> +        return 0;
>>>>> +
>>>>> +    for (i = 0; i < adev->n_regs; i++) {
>>>>> +        sprintf(reg_offset, "0x%x ", adev->reset_dump_reg_list[i]);
>>>>> +        r = copy_to_user(buf + len, reg_offset, strlen(reg_offset));
>>>>> +
>>>>> +        if (r)
>>>>> +            return -EFAULT;
>>>>> +
>>>>> +        len += strlen(reg_offset);
>>>>> +    }
>>>>> +
>>>>> +    r = copy_to_user(buf + len, "\n", 1);
>>>>> +
>>>>> +    if (r)
>>>>> +        return -EFAULT;
>>>>> +
>>>>> +    len++;
>>>>> +    *pos += len;
>>>>> +
>>>>> +    return len;
>>>>> +}
>>>>> +
>>>>> +static ssize_t amdgpu_reset_dump_register_list_write(struct file *f,
>>>>> +            const char __user *buf, size_t size, loff_t *pos)
>>>>> +{
>>>>> +    struct amdgpu_device *adev = (struct amdgpu_device 
>>>>> *)file_inode(f)->i_private;
>>>>> +    char *reg_offset, *reg, reg_temp[11];
>>>>> +    static int alloc_count;
>>>>
>>>> This being static what happens when it is called on a second device?
>>>>
>>>> Thanks,
>>>> Lijo
>>>>
>>> I tried to avoid adding to adev. It wont work for multiple devices.
>>
>> Hmm.This is not friendly for single device also. Some one could just 
>> parse a text file of reg offsets and do
>>     sudo echo offset > file
>>
>> This will overwrite whatever is there. Instead you may define a syntax 
>> like
>>     sudo echo 0x000 > file =>  Clears all
>>     sudo echo offset > file => Append to the existing set.
>>
>> Taking all offsets in one go may not be needed.
>>
>> Thanks,
>> Lijo
>>
> 
> 0x000 can be offset for some registers !

It's indeed a valid register called MM_INDEX register. The register 
doesn't have any meaning in standalone.

> This is application responsibly; any wrong data should clear the list.
> Application can read back the list for confomation.
> 

It needs to be done by user app anyway. This is more about how 
convenient the interface is. Probably you could switch to a user 
standpoint and try to add some 20-30 registers to the list. Then steps 
needed to add a revised list.

Thanks,
Lijo

> Regards,
> S.Amarnath
>>>>> +    int ret, i = 0, len = 0;
>>>>> +
>>>>> +    do {
>>>>> +        reg_offset = reg_temp;
>>>>> +        memset(reg_offset,  0, 11);
>>>>> +        ret = copy_from_user(reg_offset, buf + len, min(11, 
>>>>> ((int)size-len)));
>>>>> +
>>>>> +        if (ret)
>>>>> +            goto failed;
>>>>> +
>>>>> +        reg = strsep(&reg_offset, " ");
>>>>> +
>>>>> +        if (alloc_count <= i) {
>>>>> +            adev->reset_dump_reg_list =  krealloc_array(
>>>>> +                            adev->reset_dump_reg_list, 1,
>>>>> +                            sizeof(uint32_t), GFP_KERNEL);
>>>>> +            alloc_count++;
>>>>> +        }
>>>>> +
>>>>> +        ret = kstrtouint(reg, 16, &adev->reset_dump_reg_list[i]);
>>>>> +
>>>>> +        if (ret)
>>>>> +            goto failed;
>>>>> +
>>>>> +        len += strlen(reg) + 1;
>>>>> +        i++;
>>>>> +
>>>>> +    } while (len < size);
>>>>> +
>>>>> +    adev->n_regs = i;
>>>>> +
>>>>> +    return size;
>>>>> +
>>>>> +failed:
>>>>> +    mutex_lock(&adev->reset_dump_mutex);
>>>>> +    kfree(adev->reset_dump_reg_list);
>>>>> +    adev->reset_dump_reg_list = NULL;
>>>>> +    alloc_count = 0;
>>>>> +    adev->n_regs = 0;
>>>>> +    mutex_unlock(&adev->reset_dump_mutex);
>>>>> +    return -EFAULT;
>>>>> +}
>>>>> +
>>>>> +
>>>>> +
>>>>> +static const struct file_operations 
>>>>> amdgpu_reset_dump_register_list = {
>>>>> +    .owner = THIS_MODULE,
>>>>> +    .read = amdgpu_reset_dump_register_list_read,
>>>>> +    .write = amdgpu_reset_dump_register_list_write,
>>>>> +    .llseek = default_llseek
>>>>> +};
>>>>> +
>>>>>   int amdgpu_debugfs_init(struct amdgpu_device *adev)
>>>>>   {
>>>>>       struct dentry *root = adev_to_drm(adev)->primary->debugfs_root;
>>>>> @@ -1618,6 +1710,7 @@ int amdgpu_debugfs_init(struct amdgpu_device 
>>>>> *adev)
>>>>>       if (!debugfs_initialized())
>>>>>           return 0;
>>>>>   +    mutex_init(&adev->reset_dump_mutex);
>>>>>       ent = debugfs_create_file("amdgpu_preempt_ib", 0600, root, adev,
>>>>>                     &fops_ib_preempt);
>>>>>       if (IS_ERR(ent)) {
>>>>> @@ -1672,6 +1765,8 @@ int amdgpu_debugfs_init(struct amdgpu_device 
>>>>> *adev)
>>>>>                   &amdgpu_debugfs_test_ib_fops);
>>>>>       debugfs_create_file("amdgpu_vm_info", 0444, root, adev,
>>>>>                   &amdgpu_debugfs_vm_info_fops);
>>>>> +    debugfs_create_file("amdgpu_reset_dump_register_list", 0644, 
>>>>> root, adev,
>>>>> +                &amdgpu_reset_dump_register_list);
>>>>>         adev->debugfs_vbios_blob.data = adev->bios;
>>>>>       adev->debugfs_vbios_blob.size = adev->bios_size;
>>>>>


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