Hi Both I wrote a test code to verify the be32_to_cpu & be32_to_cpup, static int __init lkm_init(void) { char test_buf[]={0x12, 0x34, 0xab, 0xbc, 0x56, 0x78, 0xef}; unsigned int *k, p, q; int i;
printk("Hello, Shanghai!\n");
for (i = 0; i < 4; i ++) { k = (unsigned int *)&test_buf[i]; p = be32_to_cpup((__be32 *)k); q = be32_to_cpu(test_buf[i]); printk("%d: *k = 0x%08x p = 0x%08x q = 0x%08x %ld\n", i, *k, p, q, sizeof(unsigned int)); } return 0; } The output is: [ 9109.722548] Hello, Shanghai! [ 9109.726287] 0: *k = 0xbcab3412 p = 0x1234abbc q = 0x12000000 4 [ 9109.727665] 1: *k = 0x56bcab34 p = 0x34abbc56 q = 0x34000000 4 [ 9109.728553] 2: *k = 0x7856bcab p = 0xabbc5678 q = 0xabffffff 4 [ 9109.729308] 3: *k = 0xef7856bc p = 0xbc5678ef q = 0xbcffffff 4 Apparently, be32_to_cpup's output is what I expected. Looking forward to your comments. Thanks.
BR Shenghao Ding -----Original Message----- From: Christophe JAILLET christophe.jaillet@wanadoo.fr Sent: Saturday, April 1, 2023 4:41 AM To: Ding, Shenghao shenghao-ding@ti.com; Amadeusz Slawinski amadeuszx.slawinski@linux.intel.com; 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; 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
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#L...