From: Bitan Biswas <bbiswas@nvidia.com>
To: Dmitry Osipenko <digetx@gmail.com>,
Laxman Dewangan <ldewangan@nvidia.com>,
Thierry Reding <treding@nvidia.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
<linux-i2c@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, Peter Rosin <peda@axentia.se>,
Wolfram Sang <wsa@the-dreams.de>
Cc: Shardar Mohammed <smohammed@nvidia.com>,
Sowjanya Komatineni <skomatineni@nvidia.com>,
Mantravadi Karthik <mkarthik@nvidia.com>
Subject: Re: [PATCH V5 6/7] i2c: tegra: fix PIO rx/tx residual transfer check
Date: Thu, 13 Jun 2019 04:30:20 -0700 [thread overview]
Message-ID: <78140337-dca0-e340-a501-9e37eca6cc87@nvidia.com> (raw)
In-Reply-To: <42ce2523-dab9-0cdf-e8ff-42631dd161b7@gmail.com>
On 6/12/19 7:30 AM, Dmitry Osipenko wrote:
> 11.06.2019 13:51, Bitan Biswas пишет:
>> Fix expression for residual bytes(less than word) transfer
>> in I2C PIO mode RX/TX.
>>
>> Signed-off-by: Bitan Biswas <bbiswas@nvidia.com>
>> ---
>
> [snip]
>
>> /*
>> - * Update state before writing to FIFO. If this casues us
>> + * Update state before writing to FIFO. If this causes us
>> * to finish writing all bytes (AKA buf_remaining goes to 0) we
>> * have a potential for an interrupt (PACKET_XFER_COMPLETE is
>> - * not maskable). We need to make sure that the isr sees
>> - * buf_remaining as 0 and doesn't call us back re-entrantly.
>> + * not maskable).
>> */
>> buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD;
>
> Looks like the comment could be removed altogether because it doesn't
> make sense since interrupt handler is under xfer_lock which is kept
> locked during of tegra_i2c_xfer_msg().
I would push a separate patch to remove this comment because of
xfer_lock in ISR now.
>
> Moreover the comment says that "PACKET_XFER_COMPLETE is not maskable",
> but then what I2C_INT_PACKET_XFER_COMPLETE masking does?
>
I2C_INT_PACKET_XFER_COMPLETE masking support available in Tegra chips
newer than Tegra30 allows one to not see interrupt after Packet transfer
complete. With the xfer_lock in ISR the scenario discussed in comment
can be ignored.
-regards,
Bitan
next prev parent reply other threads:[~2019-06-13 15:28 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-11 10:51 [PATCH V5 1/7] i2c: tegra: clean up macros Bitan Biswas
2019-06-11 10:51 ` [PATCH V5 2/7] i2c: tegra: remove unnecessary variable init Bitan Biswas
2019-06-12 10:21 ` Wolfram Sang
2019-06-11 10:51 ` [PATCH V5 3/7] i2c: tegra: fix alignment and spacing violations Bitan Biswas
2019-06-12 10:21 ` Wolfram Sang
2019-06-11 10:51 ` [PATCH V5 4/7] i2c: tegra: add spinlock definition comment Bitan Biswas
2019-06-12 10:21 ` Wolfram Sang
2019-06-11 10:51 ` [PATCH V5 5/7] i2c: tegra: fix msleep warning Bitan Biswas
2019-06-12 10:21 ` Wolfram Sang
2019-06-11 10:51 ` [PATCH V5 6/7] i2c: tegra: fix PIO rx/tx residual transfer check Bitan Biswas
2019-06-12 10:24 ` Wolfram Sang
2019-06-13 11:43 ` Bitan Biswas
2019-06-13 11:52 ` Laxman Dewangan
2019-06-13 13:13 ` Wolfram Sang
2019-06-12 13:55 ` Dmitry Osipenko
2019-06-13 9:59 ` Bitan Biswas
2019-06-12 14:30 ` Dmitry Osipenko
2019-06-13 11:30 ` Bitan Biswas [this message]
2019-06-13 12:28 ` Dmitry Osipenko
2019-06-14 9:50 ` Bitan Biswas
2019-06-14 13:02 ` Dmitry Osipenko
2019-06-18 5:21 ` Bitan Biswas
2019-06-11 10:51 ` [PATCH V5 7/7] i2c: tegra: remove BUG, BUG_ON Bitan Biswas
2019-06-11 11:38 ` Dmitry Osipenko
2019-06-12 10:21 ` [PATCH V5 1/7] i2c: tegra: clean up macros Wolfram Sang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=78140337-dca0-e340-a501-9e37eca6cc87@nvidia.com \
--to=bbiswas@nvidia.com \
--cc=digetx@gmail.com \
--cc=jonathanh@nvidia.com \
--cc=ldewangan@nvidia.com \
--cc=linux-i2c@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tegra@vger.kernel.org \
--cc=mkarthik@nvidia.com \
--cc=peda@axentia.se \
--cc=skomatineni@nvidia.com \
--cc=smohammed@nvidia.com \
--cc=treding@nvidia.com \
--cc=wsa@the-dreams.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).