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SubjectRe: [PATCH v10] ASoC: tas2781: Add tas2781 driver
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Le 31/03/2023 à 04:19, Ding, Shenghao a écrit :
> Hi Amadeusz Sławiński
> Thanks for your comment.
> Answer inline.
>
> -----Original Message-----
> From: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
> Sent: Thursday, March 30, 2023 7:54 PM
> To: Shenghao Ding <13916275206@139.com>; broonie@kernel.org; lgirdwood@gmail.com; perex@perex.cz; pierre-louis.bossart@linux.intel.com
> Cc: Lu, Kevin <kevin-lu@ti.com>; Ding, Shenghao <shenghao-ding@ti.com>; alsa-devel@alsa-project.org; linux-kernel@vger.kernel.org; Xu, Baojun <x1077012@ti.com>; Gupta, Peeyush <peeyush@ti.com>; Navada Kanyana, Mukund <navada@ti.com>
> Subject: [EXTERNAL] Re: [PATCH v10] ASoC: tas2781: Add tas2781 driver
>
> On 3/29/2023 12:01 PM, Shenghao Ding wrote:
>> Create tas2781 driver.
>>
>> Signed-off-by: Shenghao Ding <13916275206@139.com>
>>
>> ---
>> Changes in v10:
>> - using be16_to_cpu and be32_to_cpu instead of SMS_HTONS and SMS_HTONL
>> - optimize and reduce the boundary checks
>> - Add comments on some kmemdup instead of kzalloc+memcpy
>> Changes to be committed:
>> modified: sound/soc/codecs/Kconfig
>> modified: sound/soc/codecs/Makefile
>> new file: sound/soc/codecs/tas2781-dsp.c
>> new file: sound/soc/codecs/tas2781-dsp.h
>> new file: sound/soc/codecs/tas2781-i2c.c
>> new file: sound/soc/codecs/tas2781.h
>> ---
>
> ...
>
>> +
>> +static int fw_parse_block_data_kernel(struct tasdevice_fw *tas_fmw,
>> + struct tasdev_blk *block, const struct firmware *fmw, int offset) {
>> + const unsigned char *data = fmw->data;
>> +
>> + if (offset + 16 > fmw->size) {
>> + dev_err(tas_fmw->dev, "%s: File Size error\n", __func__);
>> + offset = -EINVAL;
>> + goto out;
>> + }
>> + block->type = be32_to_cpup((__be32 *)&data[offset]);
>
> Wouldn't just be32_to_cpu(data[offset]) work instead of be32_to_cpup?
> Same in other cases.
> [DING] data[] is a char array, the code will convert data[offset], data[offset + 1],
> data[offset + 2] and data[offset + 3] into host instead of data[offset] only.
>

Not sure to follow you.
Isn't it the purpose of be32_to_cpu() to take a 32 bits word, in other
words 4 x 8 bits char, and swap what if needed (little endian arch)?

It ends to __swab32() ([1] for the "constant" implementation)


be32_to_cpup(&p) ends to __swab32(*p), which really looks to the same as
be32_to_cpu(p).

Can you elaborate more?

CJ


[1]:
https://elixir.bootlin.com/linux/v6.3-rc3/source/include/uapi/linux/swab.h#L18

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