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Mon, 22 Apr 2024 12:13:57 +0000 (GMT) Received: from nasanex01b.na.qualcomm.com (nasanex01b.na.qualcomm.com [10.46.141.250]) by NASANPPMTA01.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 43MCDu9R003025 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 22 Apr 2024 12:13:56 GMT Received: from [10.253.39.160] (10.80.80.8) by nasanex01b.na.qualcomm.com (10.46.141.250) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.9; Mon, 22 Apr 2024 05:13:54 -0700 Message-ID: <3b583308-338b-4ac8-82c2-2b4c100c9c35@quicinc.com> Date: Mon, 22 Apr 2024 20:13:52 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 1/3] bus: mhi: host: Add sysfs entry to force device to enter EDL To: Manivannan Sadhasivam CC: , , , , , References: <1713170945-44640-1-git-send-email-quic_qianyu@quicinc.com> <1713170945-44640-2-git-send-email-quic_qianyu@quicinc.com> <20240415115616.GF7537@thinkpad> <20240422072446.GA9775@thinkpad> Content-Language: en-US From: Qiang Yu In-Reply-To: <20240422072446.GA9775@thinkpad> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: nasanex01a.na.qualcomm.com (10.52.223.231) To nasanex01b.na.qualcomm.com (10.46.141.250) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: -Rb1s_NHFWl1wGrgobAdiarwOGhUMfQr X-Proofpoint-ORIG-GUID: -Rb1s_NHFWl1wGrgobAdiarwOGhUMfQr X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1011,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2024-04-22_09,2024-04-22_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 spamscore=0 impostorscore=0 lowpriorityscore=0 mlxscore=0 adultscore=0 mlxlogscore=999 bulkscore=0 suspectscore=0 malwarescore=0 clxscore=1015 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2404010003 definitions=main-2404220055 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 >>>> --- >>>> 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 .' >>> >>>> + 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 >