[PATCH 07/13] scpi: ignore init_versions failure if reported not supported

Neil Armstrong
2016-08-23T14:55:37Z

On 08/23/2016 04:54 PM, Sudeep Holla wrote:
>
>
> On 23/08/16 09:23, Neil Armstrong wrote:
>> On 08/19/2016 06:46 PM, Sudeep Holla wrote:
>>>
>>>
>>> On 18/08/16 11:11, Neil Armstrong wrote:
>>>> In Amlogic GXBB Legacy SCPI, the LEGACY_SCPI_CMD_SCPI_CAPABILITIES report
>>>> as SCPI_ERR_SUPPORT, so do not fail if this command is not supported.
>>>>
>>>> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
>>>> ---
>>>> drivers/firmware/arm_scpi.c | 12 +++++++-----
>>>> 1 file changed, 7 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/drivers/firmware/arm_scpi.c b/drivers/firmware/arm_scpi.c
>>>> index 3fe39fe..d3be4c5 100644
>>>> --- a/drivers/firmware/arm_scpi.c
>>>> +++ b/drivers/firmware/arm_scpi.c
>>>> @@ -1111,12 +1111,13 @@ err:
>>>> ret = scpi_info->ops->init_versions(scpi_info);
>>>> else
>>>> ret = scpi_init_versions(scpi_info);
>>>> - if (ret) {
>>>> + if (ret && ret != -EOPNOTSUPP) {
>>>> dev_err(dev, "incorrect or no SCP firmware found\n");
>>>> scpi_remove(pdev);
>>>> return ret;
>>>> }
>>>>
>>>
>>> Why not deal it in init_versions itself.
>>>
>>>> + if (ret != -EOPNOTSUPP) {
>>>> _dev_info(dev, "SCP Protocol %d.%d Firmware %d.%d.%d version\n",
>>>> PROTOCOL_REV_MAJOR(scpi_info->protocol_version),
>>>> PROTOCOL_REV_MINOR(scpi_info->protocol_version),
>>>
>>> Why not have default value like 0.0 ? Just add a comment. Since get
>>> version is exported out, IMO having default value makes more sense. What
>>> do you think ?
>>>
>>>> @@ -1124,15 +1125,16 @@ err:
>>>> FW_REV_MINOR(scpi_info->firmware_version),
>>>> FW_REV_PATCH(scpi_info->firmware_version));
>>>>
>>>> + ret = sysfs_create_groups(&dev->kobj, versions_groups);
>>>> + if (ret)
>>>> + dev_err(dev, "unable to create sysfs version group\n");
>>>> + }
>>>> +
>>>
>>> Again this can stay as is if we have default.
>>>
>>
>> Printing version 0.0 firmware 0.0.0 is a nonsense for me...
>>
>
> OK 0.0 was a wrong example. May be 0.1 ?
>
> Since the driver has already exposed, hypothetically user-space can use
> that information, so IMO, we need to expose some static version for pre-v1.0
>
> I am surprised that capability is not supported as this was present even
> in that legacy SCPI. Do you know what happens if you send that command ?
> Have you done some experiments on that ?
>

I've experimented and returns EOPNOTSUPP, Amlogic confirmed to us the command was not implemented.

This a clearly a corner-case.

Neil