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Message-ID: <20160201152333.GA22872@leoy-linaro>
Date: Mon, 1 Feb 2016 23:23:33 +0800
From: Leo Yan <leo.yan@...aro.org>
To: Rob Herring <robh@...nel.org>
Cc: Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Jassi Brar <jassisinghbrar@...il.com>,
Arnd Bergmann <arnd@...db.de>, Wei Xu <xuwei5@...ilicon.com>,
Tyler Baker <tyler.baker@...aro.org>,
Sudeep Holla <sudeep.holla@....com>,
Chen Feng <puck.chen@...ilicon.com>,
Bintian Wang <bintian.wang@...wei.com>,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
Haojian Zhuang <haojian.zhuang@...aro.org>
Subject: Re: [PATCH v5 1/4] dt-bindings: mailbox: Document Hi6220 mailbox
driver
Hi Rob,
Thanks for reviewing, please see below inline comments.
On Mon, Feb 01, 2016 at 08:08:28AM -0600, Rob Herring wrote:
> On Mon, Feb 01, 2016 at 09:34:44PM +0800, Leo Yan wrote:
> > Document DT binding for Hisilicon Hi6220 mailbox driver.
> >
> > Signed-off-by: Leo Yan <leo.yan@...aro.org>
> > ---
> > .../bindings/mailbox/hisilicon,hi6220-mailbox.txt | 90 ++++++++++++++++++++++
> > 1 file changed, 90 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/mailbox/hisilicon,hi6220-mailbox.txt
> >
> > diff --git a/Documentation/devicetree/bindings/mailbox/hisilicon,hi6220-mailbox.txt b/Documentation/devicetree/bindings/mailbox/hisilicon,hi6220-mailbox.txt
> > new file mode 100644
> > index 0000000..96e6acc
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mailbox/hisilicon,hi6220-mailbox.txt
> > @@ -0,0 +1,90 @@
> > +Hisilicon Hi6220 Mailbox Driver
> > +===============================
> > +
> > +Hisilicon Hi6220 mailbox supports up to 32 channels. Each channel
> > +is unidirectional with a maximum message size of 8 words. I/O is
> > +performed using register access (there is no DMA) and the cell
> > +raises an interrupt when messages are received.
> > +
> > +Mailbox Device Node:
> > +====================
> > +
> > +Required properties:
> > +--------------------
> > +- compatible: Shall be "hisilicon,hi6220-mbox"
> > +- reg: Contains the mailbox register address range (base
> > + address and length); the first item is for IPC
> > + registers, the second item is shared buffer for
> > + slots.
> > +- #mbox-cells Common mailbox binding property to identify the number
> > + of cells required for the mailbox specifier. Should be 1.
> > +- interrupts: Contains the interrupt information for the mailbox
> > + device. The format is dependent on which interrupt
> > + controller the SoCs use.
> > +
> > +Optional Properties:
> > +--------------------
> > +- hi6220,mbox-tx-noirq: Flag to allow the client user of this mailbox driver
> > + to send messages without triggering a TX completion
> > + interrupt.
>
> I don't think this belongs in DT. This should be a flag the client
> driver sets when it sends messages.
The client driver can set "tx_block = true" so use this flag indicates
the client thread should be blocked until data is transmitted.
But low level mailbox driver can use two method to support "tx_block"
mode:
- One method is to avoid using interrupt and mailbox framework will
poll with mailbox's idle flag which is set by remote processor
automatically;
- Another method is to use interrupt to notify data has been
transmitted and interrupt handler will call completion function to
wake up blocked client thread;
So this flag is to distinguish these two different hardware mechanism.
Do you think this is make sense or have other suggestion?
> > +
> > +Child Nodes:
> > +============
> > +A child node is used for representing the actual sub-mailbox device that is
> > +used for the communication between the host processor and a remote processor.
> > +Each child node should have a unique node name across all the different
> > +mailbox device nodes.
> > +
> > +Required properties:
> > +--------------------
> > +- hi6220,mbox-tx: sub-mailbox descriptor property defining Tx channel
> > +- hi6220,mbox-rx: sub-mailbox descriptor property defining Rx channel
> > +
> > +Sub-mailbox Descriptor Data
> > +---------------------------
> > +Each of the above hi6220,mbox-tx and hi6220,mbox-rx properties should have 3
> > +cells of data that represent the following:
> > + Cell #1 (slot_id) - mailbox slot id used either for transmitting
> > + (hi6220,mbox-tx) or for receiving (hi6220,mbox-rx)
> > + Cell #2 (dst_irq) - irq identifier index number which used by MCU.
> > + Cell #3 (ack_irq) - irq identifier index number with generating a tx/rx
> > + interrupt to application processor, mailbox driver
> > + used this id to acknowledge interrupt.
> > +
> > +Example:
> > +--------
> > +
> > + mailbox: mailbox@...10000 {
> > + #mbox-cells = <1>;
> > + compatible = "hisilicon,hi6220-mbox";
> > + reg = <0x0 0xF7510000 0x0 0x1000>, /* IPC_S */
> > + <0x0 0x06DFF800 0x0 0x0800>; /* Mailbox */
> > + interrupt-parent = <&gic>;
> > + interrupts = <GIC_SPI 94 IRQ_TYPE_LEVEL_HIGH>;
> > + mbox_stub_clock: mbox_stub_clock {
> > + hi6220,mbox-rx = <0 1 10>;
> > + hi6220,mbox-tx = <1 0 11>;
> > + };
> > + };
> > +
> > +
> > +Mailbox client
> > +===============
> > +
> > +"mboxes" and the optional "mbox-names" (please see
> > +Documentation/devicetree/bindings/mailbox/mailbox.txt for details). Each value
> > +of the mboxes property should contain a phandle to the mailbox controller
> > +device node and second argument is the channel index. It must be 0 (hardware
>
> 0? But the example has 1.
Will fix.
Thanks,
Leo Yan
> > +support only one channel). The equivalent "mbox-names" property value can be
> > +used to give a name to the communication channel to be used by the client user.
> > +
> > +Example:
> > +--------
> > +
> > + stub_clock: stub_clock {
> > + compatible = "hisilicon,hi6220-stub-clk";
> > + hisilicon,hi6220-clk-sram = <&sram>;
> > + #clock-cells = <1>;
> > + mbox-names = "mbox-tx";
> > + mboxes = <&mailbox 1>;
> > + };
> > --
> > 1.9.1
> >
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