mei: expose device state in sysfs

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/ABI/testing/sysfs-class-mei b/Documentation/ABI/testing/sysfs-class-mei
index 17d7444..a92d844 100644 (file)
--- 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 88b83c4..1e3edbb 100644 (file)
--- 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 cc359ae..b9fef77 100644 (file)
--- 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 b454df2..ad02097 100644 (file)
--- 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 3146df3..fca832f 100644 (file)
--- 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);