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
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