linux-kernel - Re: [PATCH 2/2] regmap: sdw: Remove 8-bit value size restriction

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <3c345192-8c92-ec92-bda7-299b852b8e4f@linux.intel.com>
Date:   Fri, 13 Jan 2023 12:03:41 -0600
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     Mark Brown <broonie@...nel.org>
Cc:     Charles Keepax <ckeepax@...nsource.cirrus.com>, vkoul@...nel.org,
        yung-chuan.liao@...ux.intel.com, sanyog.r.kale@...el.com,
        linux-kernel@...r.kernel.org, patches@...nsource.cirrus.com
Subject: Re: [PATCH 2/2] regmap: sdw: Remove 8-bit value size restriction



On 1/13/23 11:11, Mark Brown wrote:
> On Fri, Jan 13, 2023 at 10:57:39AM -0600, Pierre-Louis Bossart wrote:
> 
>> The change from reg_write/read_reg to write/read seems ok, what I was
>> asking about was the gather_write.
> 
>> +	.write = regmap_sdw_write,
>> +	.gather_write = regmap_sdw_gather_write,
>> +	.read = regmap_sdw_read,
> 
>> what happens if you only have .write and .read? What does the
>> .gather_write help with if you only use only address?
> 
> Like I said before it means that the core doesn't have to put the
> register in a linear buffer with the values, meaning it can avoid
> copying already formatted data around or allocating memory.

Ah ok, I read sideways and missed the pointer arithmetic in the write
implementation

return sdw_nwrite_no_pm(slave, addr, val_size - sizeof(addr), val +
sizeof(addr));

Thanks for the clarification.