From: Andy Gross <andy.gross@linaro.org>
To: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: david.brown@linaro.org, gregkh@linuxfoundation.org,
jslaby@suse.com, sboyd@codeaurora.org,
linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org,
linux-serial@vger.kernel.org, sramana@codeaurora.org
Subject: Re: [PATCH] tty: serial: msm: Move request_irq to the end of startup
Date: Mon, 7 Aug 2017 14:31:13 -0500 [thread overview]
Message-ID: <20170807193113.GA26499@hector.attlocal.net> (raw)
In-Reply-To: <1502086885-8390-1-git-send-email-neeraju@codeaurora.org>
On Mon, Aug 07, 2017 at 11:51:25AM +0530, Neeraj Upadhyay wrote:
> Move the request_irq() call to the end of the msm_startup(),
> so that we don't handle interrupts while msm_startup() is
> running. This avoids potential races while initialization
> is in progress. For example, consider below scenario
> where rx handler reads the intermediate value of dma->chan,
> set in msm_request_rx_dma(), and tries to do dma mapping,
> which results in data abort.
>
> uart_port_startup()
> msm_startup()
> request_irq()
> ...
> msm_request_rx_dma()
> ...
> dma->chan = dma_request_slave_channel_reason(dev, "rx");
> <UART RX IRQ>
> msm_uart_irq()
> msm_handle_rx_dm()
> msm_start_rx_dma()
> dma->desc = dma_map_single()
> <data abort>
>
> Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
This seems reasonable.
Reviewd-by: Andy Gross <andy.gross@linaro.org>
next prev parent reply other threads:[~2017-08-07 19:31 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-07 6:21 [PATCH] tty: serial: msm: Move request_irq to the end of startup Neeraj Upadhyay
2017-08-07 19:31 ` Andy Gross [this message]
2017-08-11 0:04 ` Stephen Boyd
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=20170807193113.GA26499@hector.attlocal.net \
--to=andy.gross@linaro.org \
--cc=david.brown@linaro.org \
--cc=gregkh@linuxfoundation.org \
--cc=jslaby@suse.com \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-serial@vger.kernel.org \
--cc=linux-soc@vger.kernel.org \
--cc=neeraju@codeaurora.org \
--cc=sboyd@codeaurora.org \
--cc=sramana@codeaurora.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.