From: Wolfram Sang <wsa@the-dreams.de>
To: Jan Glauber <jglauber@cavium.com>
Cc: linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org,
David Daney <ddaney@caviumnetworks.com>
Subject: Re: [PATCH v6 08/19] i2c: octeon: Enable High-Level Controller
Date: Wed, 20 Apr 2016 23:43:54 +0200 [thread overview]
Message-ID: <20160420214354.GD1546@katana> (raw)
In-Reply-To: <34aac0bb7c0ae1c0ef7ca43d087059d04d9d8b09.1460387640.git.jglauber@cavium.com>
[-- Attachment #1: Type: text/plain, Size: 2240 bytes --]
On Mon, Apr 11, 2016 at 05:28:39PM +0200, Jan Glauber wrote:
> From: David Daney <ddaney@caviumnetworks.com>
>
> Use High-Level Controller (HLC) when possible. The HLC can read/write
> up to 8 bytes and is completely optional. The most important difference
> of the HLC is that it only requires one interrupt for a transfer
> (up to 8 bytes) where the low-level read/write requires 2 interrupts
> plus one interrupt per transferred byte. Since the interrupts are costly
> using the HLC improves the performance. Also, the HLC provides improved error
> handling.
Much better description, thanks!
> + while (1) {
> + val = octeon_i2c_ctl_read(i2c);
> + if (!(val & (TWSI_CTL_STA | TWSI_CTL_STP)));
> + break;
> +
> + /* clear IFLG event */
> + if (val & TWSI_CTL_IFLG)
> + octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB);
> +
> + if (try++ > 100) {
> + pr_err("%s: giving up\n", __func__);
> + break;
> + }
> +
> + /* spin until any start/stop has finished */
> + udelay(10);
> + }
Maybe you can use one of the readx_poll_timeout() functions?
> +/**
> + * octeon_i2c_hlc_wait - wait for an HLC operation to complete
> + * @i2c: The struct octeon_i2c
> + *
> + * Returns 0 on success, otherwise a negative errno.
> + */
> +static int octeon_i2c_hlc_wait(struct octeon_i2c *i2c)
> +{
> + int time_left;
> +
> + octeon_i2c_hlc_int_enable(i2c);
> + time_left = wait_event_interruptible_timeout(i2c->queue,
> + octeon_i2c_hlc_test_ready(i2c),
> + i2c->adap.timeout);
Have you tested signal handling thoroughly? Most driver dropped the
_interruptible after a while. Mostly they found out that the state
machine of the interrupt handler couldn't gracefully deal with it and
nobody really needed the interruptible. Just saying.
> + octeon_i2c_int_disable(i2c);
> + if (!time_left) {
> + octeon_i2c_hlc_int_clear(i2c);
> + dev_dbg(i2c->dev, "%s: timeout\n", __func__);
> + return -ETIMEDOUT;
> + }
> +
> + if (time_left < 0) {
> + dev_dbg(i2c->dev, "%s: wait interrupted\n", __func__);
> + return time_left;
> + }
> + return 0;
> +}
Drop the debug messages?
I can't say much about the HW details, of course. Didn't spot anything
suspicious there.
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 819 bytes --]
next prev parent reply other threads:[~2016-04-20 21:44 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-11 15:28 [PATCH v6 00/19] i2c-octeon and i2c-thunderx drivers Jan Glauber
2016-04-11 15:28 ` [PATCH v6 01/19] i2c: octeon: Increase retry default and use fixed timeout value Jan Glauber
2016-04-13 8:39 ` Wolfram Sang
2016-04-11 15:28 ` [PATCH v6 02/19] i2c: octeon: Move set-clock and init-lowlevel upward Jan Glauber
2016-04-13 8:39 ` Wolfram Sang
2016-04-11 15:28 ` [PATCH v6 03/19] i2c: octeon: Rename [read|write]_sw to reg_[read|write] Jan Glauber
2016-04-13 8:44 ` Wolfram Sang
2016-04-14 7:58 ` Jan Glauber
2016-04-14 8:58 ` Wolfram Sang
2016-04-11 15:28 ` [PATCH v6 04/19] i2c: octeon: Introduce helper functions for register access Jan Glauber
2016-04-13 8:45 ` Wolfram Sang
2016-04-14 8:05 ` Jan Glauber
2016-04-14 8:58 ` Wolfram Sang
2016-04-11 15:28 ` [PATCH v6 05/19] i2c: octeon: Remove superfluous check in octeon_i2c_test_iflg Jan Glauber
2016-04-14 8:59 ` Wolfram Sang
2016-04-11 15:28 ` [PATCH v6 06/19] i2c: octeon: Improve error status checking Jan Glauber
2016-04-13 8:55 ` Wolfram Sang
2016-04-14 8:10 ` Jan Glauber
2016-04-14 9:01 ` Wolfram Sang
2016-04-11 15:28 ` [PATCH v6 07/19] i2c: octeon: Use i2c recovery framework Jan Glauber
2016-04-20 21:31 ` Wolfram Sang
2016-04-21 13:08 ` Jan Glauber
2016-04-21 13:54 ` Wolfram Sang
2016-04-21 17:51 ` Jan Glauber
2016-04-21 21:33 ` Wolfram Sang
2016-04-11 15:28 ` [PATCH v6 08/19] i2c: octeon: Enable High-Level Controller Jan Glauber
2016-04-20 21:43 ` Wolfram Sang [this message]
2016-04-20 21:55 ` David Daney
2016-04-21 13:40 ` Jan Glauber
2016-04-21 13:55 ` Wolfram Sang
2016-04-21 14:10 ` Jan Glauber
2016-04-11 15:28 ` [PATCH v6 09/19] dt-bindings: i2c: Add Octeon cn78xx TWSI Jan Glauber
2016-04-11 15:28 ` [PATCH v6 10/19] i2c: octeon: Add support for cn78xx chips Jan Glauber
2016-04-20 21:52 ` Wolfram Sang
2016-04-20 22:28 ` David Daney
2016-04-25 21:45 ` Wolfram Sang
2016-04-11 15:28 ` [PATCH v6 11/19] i2c: octeon: Flush TWSI writes with readback Jan Glauber
2016-04-11 15:28 ` [PATCH v6 12/19] i2c: octeon: Faster operation when IFLG signals late Jan Glauber
2016-04-11 15:28 ` [PATCH v6 13/19] i2c: octeon: Add workaround for broken irqs on CN3860 Jan Glauber
2016-04-11 15:28 ` [PATCH v6 14/19] i2c: octeon: Move read function before write Jan Glauber
2016-04-11 15:28 ` [PATCH v6 15/19] i2c: octeon: Rename driver to prepare for split Jan Glauber
2016-04-11 15:28 ` [PATCH v6 16/19] i2c: octeon: Split the driver into two parts Jan Glauber
2016-04-11 15:28 ` [PATCH v6 17/19] i2c: thunderx: Add i2c driver for ThunderX SOC Jan Glauber
2016-04-11 15:28 ` [PATCH v6 18/19] i2c: octeon,thunderx: Move register offsets to struct Jan Glauber
2016-04-11 15:28 ` [PATCH v6 19/19] i2c: thunderx: Add smbus alert support Jan Glauber
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=20160420214354.GD1546@katana \
--to=wsa@the-dreams.de \
--cc=ddaney@caviumnetworks.com \
--cc=jglauber@cavium.com \
--cc=linux-i2c@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
/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).