Re: [alsa-devel] [PATCH v7 2/2] ASoC: codecs: add wsa881x amplifier support

[Srinivas Kandagatla <srinivas.kandagatla@linaro.org>]

On 10/10/2019 14:23, Mark Brown wrote:
> On Thu, Oct 10, 2019 at 10:28:04AM +0100, Srinivas Kandagatla wrote:
>> On 09/10/2019 17:35, Mark Brown wrote:
>>> On Wed, Oct 09, 2019 at 09:51:08AM +0100, Srinivas Kandagatla wrote:
>>>> +static const u8 wsa881x_reg_readable[WSA881X_CACHE_SIZE] = {
> 
>>>> +static bool wsa881x_readable_register(struct device *dev, unsigned int reg)
>>>> +{
>>>> +	return wsa881x_reg_readable[reg];
> 
>>> There's no bounds check and that array size is not...
> 
>> I converted this now to a proper switch statement as other drivers do.
> 
>>>> +static struct regmap_config wsa881x_regmap_config = {
>>>> +	.reg_bits = 32,
>>>> +	.val_bits = 8,
>>>> +	.cache_type = REGCACHE_RBTREE,
>>>> +	.reg_defaults = wsa881x_defaults,
>>>> +	.num_reg_defaults = ARRAY_SIZE(wsa881x_defaults),
>>>> +	.max_register = WSA881X_MAX_REGISTER,
> 
>>> ...what regmap has as max_register.  Uusually you'd render as a
>>> switch statement (as you did for volatile) and let the compiler
>>> figure out a sensible way to do the lookup.
> 
>> Sorry, I did not get your point here.
> 
>> Are you saying that we can skip max_register in this regmap config ?
>> Then how would max_register in regmap be set?
> 
> I'm saying that you appear to be relying on max_register to
> verify that you're not overflowing the array bounds but you
> max_register is not set to the same thing as the array size.

Thanks for clarification, I have removed the readable array in new 
version, removed multiple macros for max register and fixed max_register 
to point to last register.

--srini
> 
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