From: "Jon Medhurst (Tixy)" <tixy@linaro.org>
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Liviu Dudau <Liviu.Dudau@arm.com>,
Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <Mark.Rutland@arm.com>,
Jassi Brar <jassisinghbrar@gmail.com>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>
Subject: Re: [PATCH 1/4] mailbox: add support for System Control and Power Interface(SCPI) protocol
Date: Thu, 30 Apr 2015 09:49:41 +0100 [thread overview]
Message-ID: <1430383781.2868.9.camel@linaro.org> (raw)
In-Reply-To: <1430310338.27241.45.camel@linaro.org>
On Wed, 2015-04-29 at 13:25 +0100, Jon Medhurst (Tixy) wrote:
> diff --git a/drivers/mailbox/scpi_protocol.c
> b/drivers/mailbox/scpi_protocol.c
> index c74575b..5818d9b 100644
> --- a/drivers/mailbox/scpi_protocol.c
> +++ b/drivers/mailbox/scpi_protocol.c
> @@ -286,14 +286,23 @@ static void scpi_tx_prepare(struct mbox_client
> *c, void *msg)
> struct scpi_chan *ch = container_of(c, struct scpi_chan, cl);
> struct scpi_shared_mem *mem = (struct scpi_shared_mem
> *)ch->tx_payload;
>
> - mem->command = cpu_to_le32(t->cmd);
> if (t->tx_buf)
> memcpy_toio(mem->payload, t->tx_buf, t->tx_len);
> if (t->rx_buf) {
> + int token;
> spin_lock_irqsave(&ch->rx_lock, flags);
> + /*
> + * Presumably we can do this token setting outside
> + * spinlock and still be safe from concurrency?
> + */
To answer my own question, yes, the four lines below can be moved up
above the spin_lock_irqsave. Because we had better be safe from
concurrency here as we are also writing to the channel's shared memory
area.
> + do
> + token = (++ch->token) & CMD_TOKEN_ID_MASK;
> + while(!token);
> + t->cmd |= token << CMD_TOKEN_ID_SHIFT;
> list_add_tail(&t->node, &ch->rx_pending);
> spin_unlock_irqrestore(&ch->rx_lock, flags);
> }
> + mem->command = cpu_to_le32(t->cmd);
> }
>
> static struct scpi_xfer *get_scpi_xfer(struct scpi_chan *ch)
--
Tixy
next prev parent reply other threads:[~2015-04-30 8:49 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-27 11:40 [PATCH 0/4] ARM64: add SCPI mailbox protocol, clock and CPUFreq support Sudeep Holla
2015-04-27 11:40 ` [PATCH 1/4] mailbox: add support for System Control and Power Interface(SCPI) protocol Sudeep Holla
2015-04-28 7:36 ` Paul Bolle
2015-04-28 8:41 ` Sudeep Holla
2015-04-28 13:54 ` Jon Medhurst (Tixy)
2015-04-29 10:53 ` Sudeep Holla
2015-04-29 11:43 ` Jon Medhurst (Tixy)
2015-04-29 12:25 ` Jon Medhurst (Tixy)
2015-04-29 13:08 ` Sudeep Holla
2015-04-30 8:49 ` Jon Medhurst (Tixy) [this message]
2015-04-29 13:01 ` Sudeep Holla
2015-05-13 16:52 ` Jassi Brar
2015-05-13 17:09 ` Sudeep Holla
2015-05-14 7:02 ` Jassi Brar
2015-05-14 7:30 ` Jassi Brar
2015-05-14 8:25 ` Sudeep Holla
2015-04-27 11:40 ` [PATCH 2/4] clk: add support for clocks provided by SCP(System Control Processor) Sudeep Holla
2015-05-07 10:17 ` Lorenzo Pieralisi
2015-05-20 23:43 ` Stephen Boyd
2015-05-26 13:14 ` Sudeep Holla
2015-04-27 11:40 ` [PATCH 3/4] clk: scpi: add support for cpufreq virtual device Sudeep Holla
2015-05-20 23:45 ` Stephen Boyd
2015-05-26 13:25 ` Sudeep Holla
2015-04-27 11:40 ` [PATCH 4/4] cpufreq: arm_big_little: add SCPI interface driver Sudeep Holla
2015-04-29 5:44 ` Viresh Kumar
2015-04-29 9:39 ` Sudeep Holla
2015-05-01 13:19 ` Jon Medhurst (Tixy)
2015-05-01 13:32 ` Sudeep Holla
2015-05-01 14:12 ` Jon Medhurst (Tixy)
2015-05-01 14:15 ` Sudeep Holla
2015-05-01 17:10 ` Jon Medhurst (Tixy)
2015-05-01 17:14 ` Sudeep Holla
2015-04-27 18:11 ` [PATCH 0/4] ARM64: add SCPI mailbox protocol, clock and CPUFreq support Jon Medhurst (Tixy)
2015-04-28 8:47 ` Sudeep Holla
2015-04-28 14:21 ` Sudeep Holla
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=1430383781.2868.9.camel@linaro.org \
--to=tixy@linaro.org \
--cc=Liviu.Dudau@arm.com \
--cc=Lorenzo.Pieralisi@arm.com \
--cc=Mark.Rutland@arm.com \
--cc=devicetree@vger.kernel.org \
--cc=jassisinghbrar@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=robh+dt@kernel.org \
--cc=sudeep.holla@arm.com \
/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 read-only IMAP folder(s) and NNTP newsgroup(s).