[PATCH linux dev-4.7] drivers: fsi: scom: Add reset functionality and sysfs interface

[Eddie James]

I'm abandoning this. The reset procedure is simple enough to do from the 
cronus ADAL layer. In FSP code it had a bunch of checks for cfam type, 
so I thought it would continue to make sense in the driver. But we don't 
need that here.

Thanks,

Eddie


On 02/20/2017 09:08 AM, Eddie James wrote:
>
>
> On 02/19/2017 11:42 PM, Joel Stanley wrote:
>> On Sat, Feb 18, 2017 at 8:11 AM, Eddie James 
>> <eajames at linux.vnet.ibm.com> wrote:
>>> From: "Edward A. James" <eajames at us.ibm.com>
>>>
>>> full reset only
>> The commit message needs some work. Use full sentences, explain why
>> the patch is required.
>
> Ok.
>
>>
>>> Signed-off-by: Edward A. James <eajames at us.ibm.com>
>>> ---
>>>   drivers/fsi/fsi-scom.c | 51 
>>> +++++++++++++++++++++++++++++++++++++++++++++++++-
>>>   1 file changed, 50 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/fsi/fsi-scom.c b/drivers/fsi/fsi-scom.c
>>> index ff8267b..c73bd91 100644
>>> --- a/drivers/fsi/fsi-scom.c
>>> +++ b/drivers/fsi/fsi-scom.c
>>> @@ -32,7 +32,10 @@
>>>   #define SCOM_DATA0_REG         0x00
>>>   #define SCOM_DATA1_REG         0x04
>>>   #define SCOM_CMD_REG           0x08
>>> +#define SCOM_FSI2PIB_RESET_REG 0x18
>>>   #define SCOM_RESET_REG         0x1C
>>> +#define SCOM_COMP_MASK_REG     0x30
>>> +#define SCOM_TRUE_MASK_REG     0x34
>>>
>>>   #define SCOM_RESET_CMD         0x80000000
>>>   #define SCOM_WRITE_CMD         0x80000000
>>> @@ -156,7 +159,7 @@ static ssize_t scom_write(struct file *filep, 
>>> const char __user *buf,
>>>          if (rc)
>>>                  dev_dbg(dev, "put_scom failed with:%d\n", rc);
>>>
>>> -       return rc;
>>> +       return rc ? rc : len;
>> This looks like an unrelated fix.
>
> Yes, I guess a separate patch is in order.
>
>>
>>>   }
>>>
>>>   static loff_t scom_llseek(struct file *file, loff_t offset, int 
>>> whence)
>>> @@ -181,6 +184,48 @@ static const struct file_operations scom_fops = {
>>>          .write  = scom_write,
>>>   };
>>>
>>> +static int scom_reset_fsi2pib(struct fsi_device *fsi_dev)
>>> +{
>>> +       int rc;
>>> +       u32 dummy = 0xFFFFFFFF;
>>> +
>>> +       rc = fsi_device_write(fsi_dev, SCOM_FSI2PIB_RESET_REG, &dummy,
>>> +                             sizeof(u32));
>>> +       if (rc)
>>> +               dev_dbg(&fsi_dev->dev,
>>> +                       "failed to write fsi2pib reset register 
>>> rc:%d\n", rc);
>> Is this expected behaviour? If not, use dev_err.
> The rest of the driver uses dev_dbg even in error situations, so I 
> tried to follow suit here.
>>
>>> +
>>> +       return rc;
>>> +}
>>> +
>>> +static int scom_full_reset(struct fsi_device *fsi_dev)
>>> +{
>>> +       int rc = 0;
>>> +       u32 dummy = 0xFFFFFFFF;
>>> +
>>> +       rc = fsi_device_write(fsi_dev, SCOM_RESET_REG, &dummy, 
>>> sizeof(u32));
>> sizeof(dummy)
>>
>>> +       if (rc) {
>>> +               dev_dbg(&fsi_dev->dev,
>>> +                       "failed to write scom reset register 
>>> rc:%d\n", rc);
>>> +               return rc;
>>> +       }
>>> +
>>> +       return scom_reset_fsi2pib(fsi_dev);
>>> +}
>>> +
>>> +static ssize_t store_reset_register(struct device *dev,
>>> +                                   struct device_attribute *attr,
>>> +                                   const char *buf, size_t count)
>>> +{
>>> +       int rc;
>>> +       struct fsi_device *fsi_dev = to_fsi_dev(dev);
>>> +
>>> +       rc = scom_full_reset(fsi_dev);
>>> +
>>> +       return rc ? rc : count;
>>> +}
>>> +DEVICE_ATTR(reset, 0200, NULL, store_reset_register);
>>> +
>>>   static int scom_probe(struct device *dev)
>>>   {
>>>          struct fsi_device *fsi_dev = to_fsi_dev(dev);
>>> @@ -200,6 +245,8 @@ static int scom_probe(struct device *dev)
>>>          scom->mdev.parent = dev;
>>>          list_add(&scom->link, &scom_devices);
>>>
>>> +       device_create_file(dev, &dev_attr_reset);
>>> +
>> What is the expected behaviour if two different userspace programs
>> have the reset and chardev open?
>
> Probably a bus error or some sort of scom error if you write reset 
> while you have a getscom/putscom operation going. Could add some locking?
>
> Thanks,
> Eddie
>
>>
>>>          return misc_register(&scom->mdev);
>>>   }
>>>
>>> @@ -207,6 +254,8 @@ static int scom_remove(struct device *dev)
>>>   {
>>>          struct scom_device *scom, *scom_tmp;
>>>          struct fsi_device *fsi_dev = to_fsi_dev(dev);
>>> +
>>> +       device_remove_file(dev, &dev_attr_reset);
>>>
>>>          list_for_each_entry_safe(scom, scom_tmp, &scom_devices, 
>>> link) {
>>>                  if (scom->fsi_dev == fsi_dev) {
>>> -- 
>>> 1.8.3.1
>>>
>