[char-misc-next 22/27] mei: fixed address clients for the new platforms

[Tomas Winkler]

From: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>

Enable by default connection to fixed address clients
from user-space for skylake and newer platform.

Signed-off-by: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>
Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
---
 drivers/misc/mei/debugfs.c | 31 +++++++++++++++++++++++++++++--
 drivers/misc/mei/hbm.c     |  4 ++++
 drivers/misc/mei/hw.h      |  6 ++++++
 drivers/misc/mei/main.c    | 18 ++++++++++++++----
 drivers/misc/mei/mei_dev.h |  4 ++++
 5 files changed, 57 insertions(+), 6 deletions(-)

diff --git a/drivers/misc/mei/debugfs.c b/drivers/misc/mei/debugfs.c
index 6bdd75424fe8..8ad406315741 100644
--- a/drivers/misc/mei/debugfs.c
+++ b/drivers/misc/mei/debugfs.c
@@ -176,6 +176,8 @@ static ssize_t mei_dbgfs_read_devstate(struct file *fp, char __user *ubuf,
 				 dev->hbm_f_dot_supported);
 		pos += scnprintf(buf + pos, bufsz - pos, "\tEV: %01d\n",
 				 dev->hbm_f_ev_supported);
+		pos += scnprintf(buf + pos, bufsz - pos, "\tFA: %01d\n",
+				 dev->hbm_f_fa_supported);
 	}
 
 	pos += scnprintf(buf + pos, bufsz - pos, "pg:  %s, %s\n",
@@ -191,6 +193,30 @@ static const struct file_operations mei_dbgfs_fops_devstate = {
 	.llseek = generic_file_llseek,
 };
 
+static ssize_t mei_dbgfs_write_allow_fa(struct file *file,
+					const char __user *user_buf,
+					size_t count, loff_t *ppos)
+{
+	struct mei_device *dev;
+	int ret;
+
+	dev = container_of(file->private_data,
+			   struct mei_device, allow_fixed_address);
+
+	ret = debugfs_write_file_bool(file, user_buf, count, ppos);
+	if (ret < 0)
+		return ret;
+	dev->override_fixed_address = true;
+	return ret;
+}
+
+static const struct file_operations mei_dbgfs_fops_allow_fa = {
+	.open = simple_open,
+	.read = debugfs_read_file_bool,
+	.write = mei_dbgfs_write_allow_fa,
+	.llseek = generic_file_llseek,
+};
+
 /**
  * mei_dbgfs_deregister - Remove the debugfs files and directories
  *
@@ -240,8 +266,9 @@ int mei_dbgfs_register(struct mei_device *dev, const char *name)
 		dev_err(dev->dev, "devstate: registration failed\n");
 		goto err;
 	}
-	f = debugfs_create_bool("allow_fixed_address", S_IRUSR | S_IWUSR, dir,
-				&dev->allow_fixed_address);
+	f = debugfs_create_file("allow_fixed_address", S_IRUSR | S_IWUSR, dir,
+				&dev->allow_fixed_address,
+				&mei_dbgfs_fops_allow_fa);
 	if (!f) {
 		dev_err(dev->dev, "allow_fixed_address: registration failed\n");
 		goto err;
diff --git a/drivers/misc/mei/hbm.c b/drivers/misc/mei/hbm.c
index e7b7aad0999b..3915b8e8d0f1 100644
--- a/drivers/misc/mei/hbm.c
+++ b/drivers/misc/mei/hbm.c
@@ -979,6 +979,10 @@ static void mei_hbm_config_features(struct mei_device *dev)
 	/* Notification Event Support */
 	if (dev->version.major_version >= HBM_MAJOR_VERSION_EV)
 		dev->hbm_f_ev_supported = 1;
+
+	/* Fixed Address Client Support */
+	if (dev->version.major_version >= HBM_MAJOR_VERSION_FA)
+		dev->hbm_f_fa_supported = 1;
 }
 
 /**
diff --git a/drivers/misc/mei/hw.h b/drivers/misc/mei/hw.h
index 4c5d6cfd79b4..459ad596df66 100644
--- a/drivers/misc/mei/hw.h
+++ b/drivers/misc/mei/hw.h
@@ -64,6 +64,12 @@
 #define HBM_MINOR_VERSION_EV               0
 #define HBM_MAJOR_VERSION_EV               2
 
+/*
+ * MEI version with fixed address client support
+ */
+#define HBM_MINOR_VERSION_FA               0
+#define HBM_MAJOR_VERSION_FA               2
+
 /* Host bus message command opcode */
 #define MEI_HBM_CMD_OP_MSK                  0x7f
 /* Host bus message command RESPONSE */
diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
index c8a8d4df84e4..3ec6236c8782 100644
--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -369,12 +369,22 @@ static int mei_ioctl_connect_client(struct file *file,
 
 	/* find ME client we're trying to connect to */
 	me_cl = mei_me_cl_by_uuid(dev, &data->in_client_uuid);
-	if (!me_cl ||
-	    (me_cl->props.fixed_address && !dev->allow_fixed_address)) {
+	if (!me_cl) {
 		dev_dbg(dev->dev, "Cannot connect to FW Client UUID = %pUl\n",
 			&data->in_client_uuid);
-		mei_me_cl_put(me_cl);
-		return  -ENOTTY;
+		rets = -ENOTTY;
+		goto end;
+	}
+
+	if (me_cl->props.fixed_address) {
+		bool forbidden = dev->override_fixed_address ?
+			 !dev->allow_fixed_address : !dev->hbm_f_fa_supported;
+		if (forbidden) {
+			dev_dbg(dev->dev, "Connection forbidden to FW Client UUID = %pUl\n",
+				&data->in_client_uuid);
+			rets = -ENOTTY;
+			goto end;
+		}
 	}
 
 	dev_dbg(dev->dev, "Connect to FW Client ID = %d\n",
diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index 70c4da015401..6d97f3335e22 100644
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -396,6 +396,7 @@ const char *mei_pg_state_str(enum mei_pg_state state);
  * @hbm_f_dc_supported  : hbm feature dynamic clients
  * @hbm_f_dot_supported : hbm feature disconnect on timeout
  * @hbm_f_ev_supported  : hbm feature event notification
+ * @hbm_f_fa_supported  : hbm feature fixed address client
  *
  * @me_clients_rwsem: rw lock over me_clients list
  * @me_clients  : list of FW clients
@@ -404,6 +405,7 @@ const char *mei_pg_state_str(enum mei_pg_state state);
  * @me_client_index : last FW client index in enumeration
  *
  * @allow_fixed_address: allow user space to connect a fixed client
+ * @override_fixed_address: force allow fixed address behavior
  *
  * @amthif_cmd_list : amthif list for cmd waiting
  * @iamthif_fp : file for current amthif operation
@@ -483,6 +485,7 @@ struct mei_device {
 	unsigned int hbm_f_dc_supported:1;
 	unsigned int hbm_f_dot_supported:1;
 	unsigned int hbm_f_ev_supported:1;
+	unsigned int hbm_f_fa_supported:1;
 
 	struct rw_semaphore me_clients_rwsem;
 	struct list_head me_clients;
@@ -491,6 +494,7 @@ struct mei_device {
 	unsigned long me_client_index;
 
 	bool allow_fixed_address;
+	bool override_fixed_address;
 
 	/* amthif list for cmd waiting */
 	struct mei_cl_cb amthif_cmd_list;
-- 
2.4.3