lkml.org 
[lkml]   [2018]   [Jun]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 08/20] coresight: dts: Cleanup device tree graph bindings
From
Date
On 11/06/18 17:52, Mathieu Poirier wrote:
> On 11 June 2018 at 03:22, Suzuki K Poulose <Suzuki.Poulose@arm.com> wrote:
>> On 08/06/18 22:22, Mathieu Poirier wrote:
>>>
>>> On Tue, Jun 05, 2018 at 10:43:19PM +0100, Suzuki K Poulose wrote:
>>>>
>>>> The coresight drivers relied on default bindings for graph
>>>> in DT, while reusing the "reg" field of the "ports" to indicate
>>>> the actual hardware port number for the connections. However,
>>>> with the rules getting stricter w.r.t to the address mismatch
>>>> with the label, it is no longer possible to use the port address
>>>> field for the hardware port number. Hence, we add an explicit
>>>> property to denote the hardware port number, "coresight,hwid"
>>>> which must be specified for each "endpoint".
>>>>
>>>> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
>>>> Cc: Sudeep Holla <sudeep.holla@arm.com>
>>>> Cc: Rob Herring <robh@kernel.org>
>>>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
>>>> ---
>>>> .../devicetree/bindings/arm/coresight.txt | 29 ++++++++++---
>>>> drivers/hwtracing/coresight/of_coresight.c | 49
>>>> +++++++++++++++++-----
>>>> 2 files changed, 62 insertions(+), 16 deletions(-)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/arm/coresight.txt
>>>> b/Documentation/devicetree/bindings/arm/coresight.txt
>>>> index ed6b555..bf75ab3 100644
>>>> --- a/Documentation/devicetree/bindings/arm/coresight.txt
>>>> +++ b/Documentation/devicetree/bindings/arm/coresight.txt
>>>> @@ -108,8 +108,13 @@ following properties to uniquely identify the
>>>> connection details.
>>>> "slave-mode"
>>
>>
>>
>>>> };
>>>
>>>
>>> For the binding part:
>>> Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>

...

>>>> @@ -140,9 +166,6 @@ static int of_coresight_parse_endpoint(struct
>>>> device_node *ep,
>>>> rparent = of_graph_get_port_parent(rep);
>>>> if (!rparent)
>>>> break;
>>>> - if (of_graph_parse_endpoint(rep, &rendpoint))
>>>> - break;
>>>> -
>>>> /* If the remote device is not available, defer probing
>>>> */
>>>> rdev = of_coresight_get_endpoint_device(rparent);
>>>> if (!rdev) {
>>>> @@ -150,9 +173,15 @@ static int of_coresight_parse_endpoint(struct
>>>> device_node *ep,
>>>> break;
>>>> }
>>>> - conn->outport = endpoint.port;
>>>> + child_port = of_coresight_endpoint_get_port_id(rdev,
>>>> rep);
>>>> + if (child_port < 0) {
>>>> + ret = 0;
>>>
>>>
>>> Why returning '0' on an error condition? Same for 'local_port' above.
>>>
>>
>> If we are unable to parse a port, we can simply ignore the port and
>> continue, which
>> is what we have today with the existing code. I didn't change it and still
>> think
>> it is the best effort thing. We could spit a warning for such cases, if
>> really needed.
>> Also, the parsing code almost never fails at the moment. If it fails to find
>> "reg" field,
>> it is assumed to be '0'. Either way ignoring it seems harmless. That said I
>> am open
>> to suggestions.
>
> Looking at the original code I remember not mandating enpoints to be
> valid for debugging purposes. That certainly helps when building up a
> device tree file but also has the side effect of silently overlooking
> specification problems. Fortunately the revamping you did on that
> part of the code makes it very easy to change that, something I think
> we should take advantage of (it can only lead to positive scenarios
> where defective specifications get pointed out).
>
> That being said and because the original behaviour is just as
> permissive, you can leave as is.

Thanks. So can I assume the Reviewed-by applies for the code now ?

Suzuki

\
 
 \ /
  Last update: 2018-06-11 18:55    [W:0.062 / U:0.096 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site