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Subject[char-misc-next 2/2] mei: expose device state in sysfs
Date
From: Alexander Usyskin <alexander.usyskin@intel.com>

Expose mei device state to user-space through sysfs.
This gives indication to applications that driver is in transition,
usefully mostly to detect link reset state.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
---
Documentation/ABI/testing/sysfs-class-mei | 15 ++++++
drivers/misc/mei/client.c | 2 +-
drivers/misc/mei/init.c | 20 +++----
drivers/misc/mei/main.c | 65 ++++++++++++++++++++---
drivers/misc/mei/mei_dev.h | 3 +-
5 files changed, 87 insertions(+), 18 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-class-mei b/Documentation/ABI/testing/sysfs-class-mei
index 17d7444a2397..a92d844f806e 100644
--- a/Documentation/ABI/testing/sysfs-class-mei
+++ b/Documentation/ABI/testing/sysfs-class-mei
@@ -65,3 +65,18 @@ Description: Display the ME firmware version.
<platform>:<major>.<minor>.<milestone>.<build_no>.
There can be up to three such blocks for different
FW components.
+
+What: /sys/class/mei/meiN/dev_state
+Date: Mar 2019
+KernelVersion: 5.1
+Contact: Tomas Winkler <tomas.winkler@intel.com>
+Description: Display the ME device state.
+
+ The device state can have following values:
+ INITIALIZING
+ INIT_CLIENTS
+ ENABLED
+ RESETTING
+ DISABLED
+ POWER_DOWN
+ POWER_UP
diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index 88b83c4bc5b7..1e3edbbacb1e 100644
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -669,7 +669,7 @@ int mei_cl_unlink(struct mei_cl *cl)

void mei_host_client_init(struct mei_device *dev)
{
- dev->dev_state = MEI_DEV_ENABLED;
+ mei_set_devstate(dev, MEI_DEV_ENABLED);
dev->reset_count = 0;

schedule_work(&dev->bus_rescan_work);
diff --git a/drivers/misc/mei/init.c b/drivers/misc/mei/init.c
index cc359ae968ce..b9fef773e71b 100644
--- a/drivers/misc/mei/init.c
+++ b/drivers/misc/mei/init.c
@@ -123,12 +123,12 @@ int mei_reset(struct mei_device *dev)

/* enter reset flow */
interrupts_enabled = state != MEI_DEV_POWER_DOWN;
- dev->dev_state = MEI_DEV_RESETTING;
+ mei_set_devstate(dev, MEI_DEV_RESETTING);

dev->reset_count++;
if (dev->reset_count > MEI_MAX_CONSEC_RESET) {
dev_err(dev->dev, "reset: reached maximal consecutive resets: disabling the device\n");
- dev->dev_state = MEI_DEV_DISABLED;
+ mei_set_devstate(dev, MEI_DEV_DISABLED);
return -ENODEV;
}

@@ -150,7 +150,7 @@ int mei_reset(struct mei_device *dev)

if (state == MEI_DEV_POWER_DOWN) {
dev_dbg(dev->dev, "powering down: end of reset\n");
- dev->dev_state = MEI_DEV_DISABLED;
+ mei_set_devstate(dev, MEI_DEV_DISABLED);
return 0;
}

@@ -162,11 +162,11 @@ int mei_reset(struct mei_device *dev)

dev_dbg(dev->dev, "link is established start sending messages.\n");

- dev->dev_state = MEI_DEV_INIT_CLIENTS;
+ mei_set_devstate(dev, MEI_DEV_INIT_CLIENTS);
ret = mei_hbm_start_req(dev);
if (ret) {
dev_err(dev->dev, "hbm_start failed ret = %d\n", ret);
- dev->dev_state = MEI_DEV_RESETTING;
+ mei_set_devstate(dev, MEI_DEV_RESETTING);
return ret;
}

@@ -196,7 +196,7 @@ int mei_start(struct mei_device *dev)

dev->reset_count = 0;
do {
- dev->dev_state = MEI_DEV_INITIALIZING;
+ mei_set_devstate(dev, MEI_DEV_INITIALIZING);
ret = mei_reset(dev);

if (ret == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
@@ -231,7 +231,7 @@ int mei_start(struct mei_device *dev)
return 0;
err:
dev_err(dev->dev, "link layer initialization failed.\n");
- dev->dev_state = MEI_DEV_DISABLED;
+ mei_set_devstate(dev, MEI_DEV_DISABLED);
mutex_unlock(&dev->device_lock);
return -ENODEV;
}
@@ -250,7 +250,7 @@ int mei_restart(struct mei_device *dev)

mutex_lock(&dev->device_lock);

- dev->dev_state = MEI_DEV_POWER_UP;
+ mei_set_devstate(dev, MEI_DEV_POWER_UP);
dev->reset_count = 0;

err = mei_reset(dev);
@@ -301,7 +301,7 @@ void mei_stop(struct mei_device *dev)
dev_dbg(dev->dev, "stopping the device.\n");

mutex_lock(&dev->device_lock);
- dev->dev_state = MEI_DEV_POWER_DOWN;
+ mei_set_devstate(dev, MEI_DEV_POWER_DOWN);
mutex_unlock(&dev->device_lock);
mei_cl_bus_remove_devices(dev);

@@ -314,7 +314,7 @@ void mei_stop(struct mei_device *dev)

mei_reset(dev);
/* move device to disabled state unconditionally */
- dev->dev_state = MEI_DEV_DISABLED;
+ mei_set_devstate(dev, MEI_DEV_DISABLED);

mutex_unlock(&dev->device_lock);
}
diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
index b454df214dde..ad02097d7fee 100644
--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -28,6 +28,12 @@
#include "mei_dev.h"
#include "client.h"

+static struct class *mei_class;
+static dev_t mei_devt;
+#define MEI_MAX_DEVS MINORMASK
+static DEFINE_MUTEX(mei_minor_lock);
+static DEFINE_IDR(mei_idr);
+
/**
* mei_open - the open function
*
@@ -829,12 +835,65 @@ static ssize_t fw_ver_show(struct device *device,
}
static DEVICE_ATTR_RO(fw_ver);

+/**
+ * dev_state_show - display device state
+ *
+ * @device: device pointer
+ * @attr: attribute pointer
+ * @buf: char out buffer
+ *
+ * Return: number of the bytes printed into buf or error
+ */
+static ssize_t dev_state_show(struct device *device,
+ struct device_attribute *attr, char *buf)
+{
+ struct mei_device *dev = dev_get_drvdata(device);
+ enum mei_dev_state dev_state;
+
+ mutex_lock(&dev->device_lock);
+ dev_state = dev->dev_state;
+ mutex_unlock(&dev->device_lock);
+
+ return sprintf(buf, "%s", mei_dev_state_str(dev_state));
+}
+static DEVICE_ATTR_RO(dev_state);
+
+static int match_devt(struct device *dev, const void *data)
+{
+ const dev_t *devt = data;
+
+ return dev->devt == *devt;
+}
+
+/**
+ * dev_set_devstate: set to new device state and notify sysfs file.
+ *
+ * @dev: mei_device
+ * @state: new device state
+ */
+void mei_set_devstate(struct mei_device *dev, enum mei_dev_state state)
+{
+ struct device *clsdev;
+
+ if (dev->dev_state == state)
+ return;
+
+ dev->dev_state = state;
+
+ clsdev = class_find_device(mei_class, NULL, &dev->cdev.dev, match_devt);
+ if (clsdev) {
+ sysfs_notify(&clsdev->kobj, NULL, "dev_state");
+ put_device(clsdev);
+ }
+}
+
static struct attribute *mei_attrs[] = {
&dev_attr_fw_status.attr,
&dev_attr_hbm_ver.attr,
&dev_attr_hbm_ver_drv.attr,
&dev_attr_tx_queue_limit.attr,
&dev_attr_fw_ver.attr,
+ &dev_attr_dev_state.attr,
NULL
};
ATTRIBUTE_GROUPS(mei);
@@ -858,12 +917,6 @@ static const struct file_operations mei_fops = {
.llseek = no_llseek
};

-static struct class *mei_class;
-static dev_t mei_devt;
-#define MEI_MAX_DEVS MINORMASK
-static DEFINE_MUTEX(mei_minor_lock);
-static DEFINE_IDR(mei_idr);
-
/**
* mei_minor_get - obtain next free device minor number
*
diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index 3146df37ffb0..fca832fcac57 100644
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -525,7 +525,6 @@ struct mei_device {
struct dentry *dbgfs_dir;
#endif /* CONFIG_DEBUG_FS */

-
const struct mei_hw_ops *ops;
char hw[0] __aligned(sizeof(void *));
};
@@ -584,6 +583,8 @@ int mei_restart(struct mei_device *dev);
void mei_stop(struct mei_device *dev);
void mei_cancel_work(struct mei_device *dev);

+void mei_set_devstate(struct mei_device *dev, enum mei_dev_state state);
+
int mei_dmam_ring_alloc(struct mei_device *dev);
void mei_dmam_ring_free(struct mei_device *dev);
bool mei_dma_ring_is_allocated(struct mei_device *dev);
--
2.20.1
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