Re: [PATCH v2 1/7] brcmfmac: Add support for host platform NVRAM loading.

[Arend van Spriel <arend@broadcom.com>]

On 08/20/2015 05:53 PM, Rafał Miłecki wrote:
> On 19 August 2015 at 23:43, Arend van Spriel <arend@broadcom.com> wrote:
>> On 08/19/2015 11:21 PM, Arend van Spriel wrote:
>>>
>>> subject changed to v2. So let's go over your beef.
>>>
>>> On 07/11/2015 07:09 PM, Rafał Miłecki wrote:
>>>>
>>>> On 10 July 2015 at 20:31, Arend van Spriel <arend@broadcom.com> wrote:
>>>>>
>>>>> @@ -146,7 +147,7 @@ brcmf_nvram_handle_value(struct nvram_parser *nvp)
>>>>>           u32 cplen;
>>>>>
>>>>>           c = nvp->data[nvp->pos];
>>>>> -       if (!is_nvram_char(c)) {
>>>>> +       if (!is_nvram_char(c) && (c != ' ')) {
>>>>
>>>>
>>>> This is redundant, please drop this change.
>>>> See fc23e81eb8f4 ("brcmfmac: allow NVRAM values to contain spaces")
>>>
>>>
>>> done
>>>
>>>>> @@ -426,19 +428,34 @@ static void brcmf_fw_request_nvram_done(const
>>>>> struct firmware *fw, void *ctx)
>>>>>           struct brcmf_fw *fwctx = ctx;
>>>>>           u32 nvram_length = 0;
>>>>>           void *nvram = NULL;
>>>>> +       u8 *data = NULL;
>>>>
>>>>
>>>> This can be const.
>>>
>>>
>>> done
>>
>>
>> Actually this is not done, but either way will require a cast because
>> bcm47xx_nvram_release_contents expects char* so there is nothing gained.
>> Unless someone will change bcm47xx_nvram_get/release_contents api to const
>> char*.
>
> Passing non-const pointer to function taking const one is OK. You
> don't need casting, compiler won't complain about this.

bcm47xx_nvram_release_contents expect a non-const pointer so the const 
data pointer needs to be cast to non-const. Which you claim is hacky.
Here is what happens when I make data pointer const:

   CC [M]  drivers/net/wireless/brcm80211/brcmfmac/firmware.o
drivers/net/wireless/brcm80211/brcmfmac/firmware.c: In function 
���brcmf_fw_request_nvram_done���:
drivers/net/wireless/brcm80211/brcmfmac/firmware.c:450:4: warning: 
passing argument 1 of ���bcm47xx_nvram_release_contents��� discards 
���const��� qualifier from pointer target type [enabled by default]
     bcm47xx_nvram_release_contents(data);
     ^
In file included from 
drivers/net/wireless/brcm80211/brcmfmac/firmware.c:22:0:
include/linux/bcm47xx_nvram.h:44:20: note: expected ���char *��� but 
argument is of type ���const u8 *���
  static inline void bcm47xx_nvram_release_contents(char *nvram)
                     ^
> On the other hand casing const pointer to the non-const one is hacky
> and I believe you should avoid that.

Either way you have to do a cast from const to non-const.

u8 *data => data = (u8 *)fw->data;
const u8 *data => bcm47xx_nvram_release_contents((char *)data);

Regards,
Arend