[PATCH V2 1/5] common: bouncebuf: Permit passing custom alignment check function

[Marek Vasut]

On 4/6/20 4:58 AM, Jaehoon Chung wrote:
> On 4/4/20 7:45 PM, Marek Vasut wrote:
>> Add extended version of the bounce_buffer_start(), which permits passing in
>> a custom alignment checker function for the buffer. This is useful e.g. on
>> systems with various DMA restrictions and where the checker function might
>> be more complex than a simple CPU cache alignment check.
>>
>> Signed-off-by: Marek Vasut <marek.vasut+renesas at gmail.com>
>> Cc: Daniel Schwierzeck <daniel.schwierzeck at gmail.com>
>> Cc: Masahiro Yamada <yamada.masahiro at socionext.com>
>> Cc: Peng Fan <peng.fan at nxp.com>
>> Cc: Simon Glass <sjg at chromium.org>
>> Cc: Tom Rini <trini at konsulko.com>
>> ---
>> V2: No change
>> ---
>>  common/bouncebuf.c  | 20 +++++++++++++++-----
>>  include/bouncebuf.h | 15 +++++++++++++++
>>  2 files changed, 30 insertions(+), 5 deletions(-)
>>
>> diff --git a/common/bouncebuf.c b/common/bouncebuf.c
>> index 614eb36c78..0ace152b98 100644
>> --- a/common/bouncebuf.c
>> +++ b/common/bouncebuf.c
>> @@ -31,17 +31,19 @@ static int addr_aligned(struct bounce_buffer *state)
>>  	return 1;
>>  }
>>  
>> -int bounce_buffer_start(struct bounce_buffer *state, void *data,
>> -			size_t len, unsigned int flags)
>> +int bounce_buffer_start_extalign(struct bounce_buffer *state, void *data,
>> +				 size_t len, unsigned int flags,
>> +				 size_t alignment,
>> +				 int (*addr_is_aligned)(struct bounce_buffer *state))
>>  {
>>  	state->user_buffer = data;
>>  	state->bounce_buffer = data;
>>  	state->len = len;
>> -	state->len_aligned = roundup(len, ARCH_DMA_MINALIGN);
>> +	state->len_aligned = roundup(len, alignment);
>>  	state->flags = flags;
>>  
>> -	if (!addr_aligned(state)) {
>> -		state->bounce_buffer = memalign(ARCH_DMA_MINALIGN,
>> +	if (!addr_is_aligned(state)) {
> 
> how about checking condition whether addr_is_aligned function is present or not at here?

If it's not present, then you're misusing this function.