From: Qiang Yu <quic_qianyu@quicinc.com>
To: Manivannan Sadhasivam <mani@kernel.org>
Cc: <quic_jhugo@quicinc.com>, <mhi@lists.linux.dev>,
<linux-arm-msm@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<quic_cang@quicinc.com>, <quic_mrana@quicinc.com>
Subject: Re: [PATCH v3 1/3] bus: mhi: host: Add sysfs entry to force device to enter EDL
Date: Mon, 22 Apr 2024 20:13:52 +0800 [thread overview]
Message-ID: <3b583308-338b-4ac8-82c2-2b4c100c9c35@quicinc.com> (raw)
In-Reply-To: <20240422072446.GA9775@thinkpad>
On 4/22/2024 3:24 PM, Manivannan Sadhasivam wrote:
> On Tue, Apr 16, 2024 at 01:45:18PM +0800, Qiang Yu wrote:
>> On 4/15/2024 7:56 PM, Manivannan Sadhasivam wrote:
>>> On Mon, Apr 15, 2024 at 04:49:03PM +0800, Qiang Yu wrote:
>>>> Add sysfs entry to allow users of MHI bus force device to enter EDL.
>>>> Considering that the way to enter EDL mode varies from device to device and
>>>> some devices even do not support EDL. Hence, add a callback edl_trigger in
>>>> mhi controller as part of the sysfs entry to be invoked and MHI core will
>>>> only create EDL sysfs entry for mhi controller that provides edl_trigger
>>>> callback. All of the process a specific device required to enter EDL mode
>>>> can be placed in this callback.
>>>>
>>>> Signed-off-by: Qiang Yu <quic_qianyu@quicinc.com>
>>>> ---
>>>> Documentation/ABI/stable/sysfs-bus-mhi | 11 +++++++++++
>>>> drivers/bus/mhi/host/init.c | 35 ++++++++++++++++++++++++++++++++++
>>>> include/linux/mhi.h | 2 ++
>>>> 3 files changed, 48 insertions(+)
>>>>
>>>> diff --git a/Documentation/ABI/stable/sysfs-bus-mhi b/Documentation/ABI/stable/sysfs-bus-mhi
>>>> index 1a47f9e..d0bf9ae 100644
>>>> --- a/Documentation/ABI/stable/sysfs-bus-mhi
>>>> +++ b/Documentation/ABI/stable/sysfs-bus-mhi
>>>> @@ -29,3 +29,14 @@ Description: Initiates a SoC reset on the MHI controller. A SoC reset is
>>>> This can be useful as a method of recovery if the device is
>>>> non-responsive, or as a means of loading new firmware as a
>>>> system administration task.
>>>> +
>>>> +What: /sys/bus/mhi/devices/.../force_edl
>>> s/force_edl/trigger_edl
>>>
>>>> +Date: April 2024
>>>> +KernelVersion: 6.9
>>>> +Contact: mhi@lists.linux.dev
>>>> +Description: Force devices to enter EDL (emergency download) mode. Only MHI
>>> How can the user trigger EDL mode? Writing to this file? If so, what is the
>>> value?
>> User can trigger EDL mode by writing a non-zero value to this file.
>>
>>> 'Emergency Download'
>>>
>>>> + controller that supports EDL mode and provides a mechanism for
>>>> + manually triggering EDL contains this file. Once in EDL mode,
>>> 'This entry only exists for devices capable of entering the EDL mode using the
>>> standard EDL triggering mechanism defined in the MHI spec <insert the version>.'
>>>
>>>> + the flash programmer image can be downloaded to the device to
>>>> + enter the flash programmer execution environment. This can be
>>>> + useful if user wants to update firmware.
>>> It'd be good to mention the OS tool like QDL that is used to download firmware
>>> over EDL.
>> OK, can I add an additionnal line like this
>> Users: Any OS tools that is used to download firmware over EDL like
>> QDL.
>>
>>>> diff --git a/drivers/bus/mhi/host/init.c b/drivers/bus/mhi/host/init.c
>>>> index 44f9349..333ac94 100644
>>>> --- a/drivers/bus/mhi/host/init.c
>>>> +++ b/drivers/bus/mhi/host/init.c
>>>> @@ -127,6 +127,32 @@ static ssize_t soc_reset_store(struct device *dev,
>>>> }
>>>> static DEVICE_ATTR_WO(soc_reset);
>>>> +static ssize_t force_edl_store(struct device *dev,
>>> s/force_edl/trigger_edl
>>>
>>>> + struct device_attribute *attr,
>>>> + const char *buf, size_t count)
>>>> +{
>>>> + struct mhi_device *mhi_dev = to_mhi_device(dev);
>>>> + struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
>>>> + unsigned long val;
>>>> + int ret;
>>>> +
>>>> + ret = kstrtoul(buf, 10, &val);
>>>> + if (ret < 0) {
>>>> + dev_err(dev, "Could not parse string: %d\n", ret);
>>> No need to print error.
>>>
>>>> + return ret;
>>>> + }
>>>> +
>>>> + if (!val)
>>>> + return count;
>>> What does this mean?
>> If user want to trigger EDL mode,he has to write a non-zero value to this
>> file. If he writes zero, nothing will happen.
>>
> You need to throw -EINVAL for invalid inputs ie., <= 0.
Thanks for pointing this out. Will also address it in next version
patch.
Thanks,
Qiang
>> Do we need to limit the valid value to a specific value like 1?
>>
> That's not needed.
>
> - Mani
>
next prev parent reply other threads:[~2024-04-22 12:14 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-15 8:49 [PATCH v3 0/3] Add sysfs entry to EDL mode Qiang Yu
2024-04-15 8:49 ` [PATCH v3 1/3] bus: mhi: host: Add sysfs entry to force device to enter EDL Qiang Yu
2024-04-15 11:56 ` Manivannan Sadhasivam
2024-04-16 5:45 ` Qiang Yu
2024-04-22 7:24 ` Manivannan Sadhasivam
2024-04-22 12:13 ` Qiang Yu [this message]
2024-04-15 8:49 ` [PATCH v3 2/3] bus: mhi: host: Add a new API for getting channel doorbell address Qiang Yu
2024-04-15 12:02 ` Manivannan Sadhasivam
2024-04-15 8:49 ` [PATCH v3 3/3] bus: mhi: host: pci_generic: Add edl callback to enter EDL Qiang Yu
2024-04-15 12:12 ` Manivannan Sadhasivam
2024-04-15 23:53 ` Mayank Rana
2024-04-16 3:50 ` Qiang Yu
2024-04-16 18:12 ` Mayank Rana
2024-04-17 3:01 ` Qiang Yu
2024-04-17 4:41 ` Qiang Yu
2024-04-18 17:37 ` Mayank Rana
2024-04-22 8:08 ` Manivannan Sadhasivam
2024-04-22 12:06 ` Qiang Yu
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