linux-kernel - Re: [PATCH v2 2/8] dt-bindings: remoteproc: add bindings for stm32 remote processor driver

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Message-ID: <ff424530-6e7b-cec9-910f-1897d60de2a1@st.com>
Date:   Tue, 30 Apr 2019 14:14:56 +0000
From:   Fabien DESSENNE <fabien.dessenne@...com>
To:     Rob Herring <robh@...nel.org>
CC:     Mark Rutland <mark.rutland@....com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre TORGUE <alexandre.torgue@...com>,
        "Ohad Ben-Cohen" <ohad@...ery.com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-stm32@...md-mailman.stormreply.com" 
        <linux-stm32@...md-mailman.stormreply.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-remoteproc@...r.kernel.org" <linux-remoteproc@...r.kernel.org>,
        Loic PALLARDY <loic.pallardy@...com>,
        Arnaud POULIQUEN <arnaud.pouliquen@...com>,
        Ludovic BARRE <ludovic.barre@...com>,
        Benjamin GAIGNARD <benjamin.gaignard@...com>
Subject: Re: [PATCH v2 2/8] dt-bindings: remoteproc: add bindings for stm32
 remote processor driver

Hi Rob,


On 30/04/2019 2:40 AM, Rob Herring wrote:
> On Tue, Apr 16, 2019 at 04:58:13PM +0200, Fabien Dessenne wrote:
>> Add the device tree bindings document for the stm32 remoteproc devices.
>>
>> Signed-off-by: Fabien Dessenne <fabien.dessenne@...com>
>> ---
>>   .../devicetree/bindings/remoteproc/stm32-rproc.txt | 64 ++++++++++++++++++++++
>>   1 file changed, 64 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/remoteproc/stm32-rproc.txt
>>
>> diff --git a/Documentation/devicetree/bindings/remoteproc/stm32-rproc.txt b/Documentation/devicetree/bindings/remoteproc/stm32-rproc.txt
>> new file mode 100644
>> index 0000000..430132c
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/remoteproc/stm32-rproc.txt
>> @@ -0,0 +1,64 @@
>> +STMicroelectronics STM32 Remoteproc
>> +-----------------------------------
>> +This document defines the binding for the remoteproc component that loads and
>> +boots firmwares on the ST32MP family chipset.
>> +
>> +Required properties:
>> +- compatible:	Must be "st,stm32mp1-m4"
>> +- reg:		Address ranges of the remote processor dedicated memories.
>> +		The parent node should provide an appropriate ranges property
>> +		for properly translating these into bus addresses.
> dma-ranges, but that's independent of 'reg'.
>
> It needs to list how many reg regions and what they are.

The "reg" property needs to be removed since it is not used by the 
driver : the "memory-region" property (defined below) provides with all 
the needed memory information.

Unfortunately, when I remove this "reg" property from the DeviceTree, I 
have this warning when building (W=123) the DTB:

  "Warning (avoid_unnecessary_addr_size): /mlahb: unnecessary 
#address-cells/#size-cells without "ranges" or child "reg" property"

IMHO, there is something wrong in the dtc script which seems to ignore 
the "dma-ranges" property that needs to have #address-cells/#size-cells 
defined. Just like "ranges".

The quick patch below (add check for "dma-ranges" ) in 
scripts/dtc/checks.c solves this issue.

static void check_avoid_unnecessary_addr_size(struct check *c, struct 
dt_info *dti,
                           struct node *node)
{
...
     if (get_property(node, "ranges") || get_property(node, 
"dma-ranges") || !node->children)
         return;
...

Can you confirm that I can remove the "reg" property and ignore the warning?

BR

Fabien


>
>> +- resets:	Reference to a reset controller asserting the remote processor.
>> +- st,syscfg-holdboot: Reference to the system configuration which holds the
>> +		remote processor reset hold boot
>> +	1st cell: phandle of syscon block
>> +	2nd cell: register offset containing the hold boot setting
>> +	3rd cell: register bitmask for the hold boot field
>> +- st,syscfg-tz: Reference to the system configuration which holds the RCC trust
>> +		zone mode
>> +	1st cell: phandle to syscon block
>> +	2nd cell: register offset containing the RCC trust zone mode setting
>> +	3rd cell: register bitmask for the RCC trust zone mode bit
>> +
>> +Optional properties:
>> +- interrupts:	Should contain the watchdog interrupt
>> +- mboxes:	This property is required only if the rpmsg/virtio functionality
>> +		is used. List of phandle and mailbox channel specifiers:
>> +		- a channel (a) used to communicate through virtqueues with the
>> +		  remote proc.
>> +		  Bi-directional channel:
>> +		      - from local to remote = send message
>> +		      - from remote to local = send message ack
>> +		- a channel (b) working the opposite direction of channel (a)
>> +		- a channel (c) used by the local proc to notify the remote proc
>> +		  that it is about to be shut down.
>> +		  Unidirectional channel:
>> +		      - from local to remote, where ACK from the remote means
>> +		        that it is ready for shutdown
>> +- mbox-names:	This property is required if the mboxes property is used.
>> +		- must be "vq0" for channel (a)
>> +		- must be "vq1" for channel (b)
>> +		- must be "shutdown" for channel (c)
>> +- memory-region: List of phandles to the reserved memory regions associated with
>> +		the remoteproc device. This is variable and describes the
>> +		memories shared with the remote processor (eg: remoteproc
>> +		firmware and carveouts, rpmsg vrings, ...).
>> +		(see ../reserved-memory/reserved-memory.txt)
>> +- st,syscfg-pdds: Reference to the system configuration which holds the remote
>> +		processor deep sleep setting
>> +	1st cell: phandle to syscon block
>> +	2nd cell: register offset containing the deep sleep setting
>> +	3rd cell: register bitmask for the deep sleep bit
>> +- auto_boot:	If defined, when remoteproc is probed, it loads the default
>> +		firmware and starts the remote processor.
> st,auto-boot
>
>> +
>> +Example:
>> +	m4_rproc: m4@0 {
>> +		compatible = "st,stm32mp1-m4";
>> +		reg = <0x00000000 0x10000>,
>> +		      <0x10000000 0x40000>,
>> +		      <0x30000000 0x40000>;
>> +		resets = <&rcc MCU_R>;
>> +		st,syscfg-holdboot = <&rcc 0x10C 0x1>;
>> +		st,syscfg-tz = <&rcc 0x000 0x1>;
>> +	};
>> -- 
>> 2.7.4
>>