Messages in this thread | | | From | "Ding, Shenghao" <> | Subject | RE: [EXTERNAL] Re: [PATCH v10] ASoC: tas2781: Add tas2781 driver | Date | Wed, 5 Apr 2023 11:21:33 +0000 |
| |
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#L18
| |