linux-kernel - Re: [PATCH v7 2/2] drivers: soc: Add LLCC driver

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Message-ID: <CAHp75Vd8HZU+BT38-OfXHiihv1yZG6YBeMWyfweBA+kAwk6HUw@mail.gmail.com>
Date:   Tue, 22 May 2018 22:38:36 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Rishabh Bhatnagar <rishabhb@...eaurora.org>
Cc:     linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
        linux-arm-msm@...r.kernel.org,
        devicetree <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-arm@...ts.infradead.org, tsoni@...eaurora.org,
        ckadabi@...eaurora.org, Evan Green <evgreen@...omium.org>,
        Rob Herring <robh@...nel.org>
Subject: Re: [PATCH v7 2/2] drivers: soc: Add LLCC driver

On Tue, May 22, 2018 at 9:33 PM,  <rishabhb@...eaurora.org> wrote:
> On 2018-05-18 14:01, Andy Shevchenko wrote:
>> On Wed, May 16, 2018 at 8:43 PM, Rishabh Bhatnagar
>> <rishabhb@...eaurora.org> wrote:

>>> +#define ACTIVATE                      0x1
>>> +#define DEACTIVATE                    0x2
>>> +#define ACT_CTRL_OPCODE_ACTIVATE      0x1
>>> +#define ACT_CTRL_OPCODE_DEACTIVATE    0x2
>>> +#define ACT_CTRL_ACT_TRIG             0x1
>>
>>
>> Are these bits? Perhaps BIT() ?
>>
> isn't it just better to use fixed size as u suggest in the next comment?

If the are bits, use BIT() macro.

>>> +struct llcc_slice_desc *llcc_slice_getd(u32 uid)
>>> +{
>>> +       const struct llcc_slice_config *cfg;
>>> +       struct llcc_slice_desc *desc;
>>> +       u32 sz, count = 0;
>>> +
>>> +       cfg = drv_data->cfg;
>>> +       sz = drv_data->cfg_size;
>>> +
>>
>>
>>> +       while (cfg && count < sz) {
>>> +               if (cfg->usecase_id == uid)
>>> +                       break;
>>> +               cfg++;
>>> +               count++;
>>> +       }
>>> +       if (cfg == NULL || count == sz)
>>> +               return ERR_PTR(-ENODEV);
>>
>>
>> if (!cfg)
>>           return ERR_PTR(-ENODEV);
>>
>> while (cfg->... != uid) {
>>   cfg++;
>>   count++;
>> }
>>
>> if (count == sz)
>>  return ...
>>
>> Though I would rather put it to for () loop.
>>
> In each while loop iteration the cfg pointer needs to be checked for
> NULL. What if the usecase id never matches the uid passed by client
> and we keep iterating. At some point it will crash.

do {
  if (!cfg || count == sz)
   return ...(-ENODEV);
 ...
} while (...);

Though, as I said for-loop will look slightly better I think.

>>> +       ret = llcc_update_act_ctrl(desc->slice_id, act_ctrl_val,
>>> +                                 DEACTIVATE);
>>
>>
>> Perhaps one line (~83 characters here is OK) ?
>
> The checkpatch script complains about such lines.

So what if it just 3 characters out?

>>> +       ret = llcc_update_act_ctrl(desc->slice_id, act_ctrl_val,
>>> +                                 ACTIVATE);

>> Ditto.

>>> +               attr1_cfg = bcast_off +
>>> +
>>> LLCC_TRP_ATTR1_CFGn(llcc_table[i].slice_id);
>>> +               attr0_cfg = bcast_off +
>>> +
>>> LLCC_TRP_ATTR0_CFGn(llcc_table[i].slice_id);

>> Ditto.

>>> +               attr1_val |= llcc_table[i].probe_target_ways <<
>>> +                               ATTR1_PROBE_TARGET_WAYS_SHIFT;
>>> +               attr1_val |= llcc_table[i].fixed_size <<
>>> +                               ATTR1_FIXED_SIZE_SHIFT;
>>> +               attr1_val |= llcc_table[i].priority <<
>>> ATTR1_PRIORITY_SHIFT;

>> foo |=
>>   bar << SHIFT;
>>
>> would look slightly better.

Did you consider this option ?

-- 
With Best Regards,
Andy Shevchenko