Re: [PATCH v3 1/3] bus: mhi: host: Add sysfs entry to force device to enter EDL
From: Qiang Yu
Date: Mon Apr 22 2024 - 08:14:10 EST
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@xxxxxxxxxxx>
---
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@xxxxxxxxxxxxxxx
+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