Re: [PATCH v4 2/5] gpio: Add support for Intel LJCA USB GPIO driver

Oliver Neukum
2023-03-09T17:37:51Z

On 09.03.23 15:48, Arnd Bergmann wrote:
> On Thu, Mar 9, 2023, at 15:18, Linus Walleij wrote:
>> On Thu, Mar 9, 2023 at 2:53 PM Andy Shevchenko
>> <andriy.shevchenko@linux.intel.com> wrote:
>>
>> Yups. And I think the solution looks something like this:
>>
>> u8 obuf[LJCA_GPIO_BUF_SIZE] __aligned(8);
>> u8 ibuf[LJCA_GPIO_BUF_SIZE] __aligned(8);
>>
>> __aligned(4) if it's 32bit DMA I guess? 8 always works that's
>> why we use it all over the IIO subsystem.
>
> I think it must be __aligned(ARCH_DMA_MINALIGN), to account
> for architectures with non-coherent DMA.

In theory, yes, you can do that.
Is that a better solution than using what kmalloc() is
designed to provide. I don't think so.

Regards
Oliver