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SubjectRe: [PATCH v4] platform/chrome: mfd/cros_ec_debugfs: Add debugfs entry to retrieve EC uptime.
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Hi Tim,

Sorry for making you wait so much, now that the patches about cros_ec_commands
include file has been accepted and the struct is up-to-date I can manage this.
I've some few comments though, one of them is a change I requested but that now
we should revert (sorry about that)

Please rebase the patch on top of chrome-platform-5.3, there are trivial conflicts.

On 2/5/19 23:16, Enric Balletbo Serra wrote:
> Hi Tim,
>
> Missatge de Tim Wawrzynczak <twawrzynczak@chromium.org> del dia dj., 2
> de maig 2019 a les 18:10:
>>
>> The new debugfs entry 'uptime' is being made available to userspace so that
>> a userspace daemon can synchronize EC logs with host time.
>>
>> Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
>> ---
>> Enric, is there something I can do to help speed this along? This patch
>> is useful for ChromeOS board bringup, and we would like to see it upstreamed
>> if at all possible.
>>
>
> The last version looks good to me. The patch is in my list but is too
> late for the next merge window. Will be one of the first patches I'll
> queue for 5.3
>
> Thanks,
> Enric
>
>> Also, AFAIK only the cros_ec supports the 'uptime' command for now.
>> And yes, the file does need to be seekable; the userspace daemon that
>> consumes the file keeps the file open and seeks back to the beginning
>> to get the latest uptime value.
>> Based on your second response to v3, I kept the separate 'create_uptime'
>> function b/c of the logic for checking support for the uptime command.
>> Let me know if you'd like me to move all of that logic into _probe.
>>
>> Changelist from v3:
>> 1) Don't check return values of debugfs_* functions.
>> 2) Only expose 'uptime' file if EC supports it.
>> ---
>> Documentation/ABI/testing/debugfs-cros-ec | 10 +++
>> drivers/platform/chrome/cros_ec_debugfs.c | 78 +++++++++++++++++++++++
>> 2 files changed, 88 insertions(+)
>> create mode 100644 Documentation/ABI/testing/debugfs-cros-ec
>>
>> diff --git a/Documentation/ABI/testing/debugfs-cros-ec b/Documentation/ABI/testing/debugfs-cros-ec
>> new file mode 100644
>> index 000000000000..24b781c67a4c
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/debugfs-cros-ec
>> @@ -0,0 +1,10 @@
>> +What: /sys/kernel/debug/cros_ec/uptime

Although for now only cros_ec supports it, let's use <cros-ec-device> for
possible future uses.

/sys/kernel/debug/<cros-ec-device>/uptime

>> +Date: March 2019
>> +KernelVersion: 5.1

Will be 5.3

>> +Description:
>> + Read-only.
>> + Reads the EC's current uptime information
>> + (using EC_CMD_GET_UPTIME_INFO) and prints
>> + time_since_ec_boot_ms into the file.
>> + This is used for synchronizing AP host time
>> + with the cros_ec log.
>> diff --git a/drivers/platform/chrome/cros_ec_debugfs.c b/drivers/platform/chrome/cros_ec_debugfs.c
>> index 71308766e891..226545a2150b 100644
>> --- a/drivers/platform/chrome/cros_ec_debugfs.c
>> +++ b/drivers/platform/chrome/cros_ec_debugfs.c
>> @@ -201,6 +201,50 @@ static int cros_ec_console_log_release(struct inode *inode, struct file *file)
>> return 0;
>> }
>>
>> +static int cros_ec_get_uptime(struct cros_ec_device *ec_dev, u32 *uptime)
>> +{
>> + struct {
>> + struct cros_ec_command msg;
>> + struct ec_response_uptime_info resp;
>> + } __packed ec_buf;
>> + struct ec_response_uptime_info *resp;
>> + struct cros_ec_command *msg;
>> +
>> + msg = &ec_buf.msg;
>> + resp = (struct ec_response_uptime_info *)msg->data;
>> +
>> + msg->command = EC_CMD_GET_UPTIME_INFO;
>> + msg->version = 0;
>> + msg->insize = sizeof(*resp);
>> + msg->outsize = 0;
>> +
>> + ret = cros_ec_cmd_xfer_status(ec_dev, msg);
>> + if (ret < 0)
>> + return ret;
>> +
>> + *uptime = resp->time_since_ec_boot_ms;
>> + return 0;
>> +}
>> +
>> +static ssize_t cros_ec_uptime_read(struct file *file,
>> + char __user *user_buf,
>> + size_t count,
>> + loff_t *ppos)
>> +{
>> + struct cros_ec_debugfs *debug_info = file->private_data;
>> + struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
>> + char read_buf[32];
>> + int ret;
>> + u32 uptime;
>> +
>> + ret = cros_ec_get_uptime(ec_dev, &uptime);
>> + if (ret < 0)
>> + return ret;
>> +
>> + ret = scnprintf(read_buf, sizeof(read_buf), "%u\n", uptime);
>> + return simple_read_from_buffer(user_buf, count, ppos, read_buf, ret);
>> +}
>> +
>> static ssize_t cros_ec_pdinfo_read(struct file *file,
>> char __user *user_buf,
>> size_t count,
>> @@ -269,6 +313,13 @@ const struct file_operations cros_ec_pdinfo_fops = {
>> .llseek = default_llseek,
>> };
>>
>> +const struct file_operations cros_ec_uptime_fops = {
>> + .owner = THIS_MODULE,
>> + .open = simple_open,
>> + .read = cros_ec_uptime_read,
>> + .llseek = default_llseek,
>> +};
>> +
>> static int ec_read_version_supported(struct cros_ec_dev *ec)
>> {
>> struct ec_params_get_cmd_versions_v1 *params;
>> @@ -413,6 +464,29 @@ static int cros_ec_create_pdinfo(struct cros_ec_debugfs *debug_info)
>> return 0;
>> }
>>
>> +static int cros_ec_create_uptime(struct cros_ec_debugfs *debug_info)
>> +{
>> + struct cros_ec_debugfs *debug_info = file->private_data;
>> + struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
>> + u32 uptime;
>> + int ret;
>> +
>> + /*
>> + * If the EC does not support the uptime command, which is
>> + * indicated by xfer_status() returning -EINVAL, then no
>> + * debugfs entry will be created.
>> + */
>> + ret = cros_ec_get_uptime(ec_dev, &uptime);
>> +
>> + if (ret == -EINVAL)
>> + return supported;

That doesn't apply anymore, xfer_status will not return -EINVAL (sorry to make
you change this before)

>> +
>> + debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
>> + &cros_ec_uptime_fops);
>> +
>> + return 0;
>> +}
>> +


Let's remove this function and just do

>> static int cros_ec_debugfs_probe(struct platform_device *pd)
>> {
>> struct cros_ec_dev *ec = dev_get_drvdata(pd->dev.parent);
>> @@ -442,6 +516,10 @@ static int cros_ec_debugfs_probe(struct platform_device *pd)
>> if (ret)
>> goto remove_log;
>>


If the command fails just don't create the file silently. No need to remove the
other files just because this fails.

if (cros_ec_get_uptime() == 0)
debugfs_create_file("uptime", 0444, debug_info->dir, debug_info,
&cros_ec_uptime_fops);

Thanks,
Enric

>> + ret = cros_ec_create_uptime(debug_info);
>> + if (ret)
>> + goto remove_log;
>> +
>> ec->debug_info = debug_info;
>>
>> dev_set_drvdata(&pd->dev, ec);
>> --
>> 2.20.1
>>

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