mei: use structured buffer for the write buffer

We can drop useless castings and use proper types.
We remove the casting in mei_hbm_hdr function
and add new function mei_hbm_stop_request_prepare that
utilize the new structure

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

5 files changed, 108 insertions, 105 deletions

diff --git a/drivers/misc/mei/amthif.c b/drivers/misc/mei/amthif.c
index bb613f733309..f9d458cced21 100644
--- a/drivers/misc/mei/amthif.c
+++ b/drivers/misc/mei/amthif.c
@@ -432,34 +432,33 @@ unsigned int mei_amthif_poll(struct mei_device *dev,
 int mei_amthif_irq_write_complete(struct mei_device *dev, s32 *slots,
                         struct mei_cl_cb *cb, struct mei_cl_cb *cmpl_list)
 {
-        struct mei_msg_hdr *mei_hdr;
+        struct mei_msg_hdr mei_hdr;
         struct mei_cl *cl = cb->cl;
         size_t len = dev->iamthif_msg_buf_size - dev->iamthif_msg_buf_index;
         size_t msg_slots = mei_data2slots(len);
 
-        mei_hdr = (struct mei_msg_hdr *)&dev->wr_msg_buf[0];
-        mei_hdr->host_addr = cl->host_client_id;
-        mei_hdr->me_addr = cl->me_client_id;
-        mei_hdr->reserved = 0;
+        mei_hdr.host_addr = cl->host_client_id;
+        mei_hdr.me_addr = cl->me_client_id;
+        mei_hdr.reserved = 0;
 
         if (*slots >= msg_slots) {
-                mei_hdr->length = len;
-                mei_hdr->msg_complete = 1;
+                mei_hdr.length = len;
+                mei_hdr.msg_complete = 1;
         /* Split the message only if we can write the whole host buffer */
         } else if (*slots == dev->hbuf_depth) {
                 msg_slots = *slots;
                 len = (*slots * sizeof(u32)) - sizeof(struct mei_msg_hdr);
-                mei_hdr->length = len;
-                mei_hdr->msg_complete = 0;
+                mei_hdr.length = len;
+                mei_hdr.msg_complete = 0;
         } else {
                 /* wait for next time the host buffer is empty */
                 return 0;
         }
 
-        dev_dbg(&dev->pdev->dev, MEI_HDR_FMT,  MEI_HDR_PRM(mei_hdr));
+        dev_dbg(&dev->pdev->dev, MEI_HDR_FMT,  MEI_HDR_PRM(&mei_hdr));
 
         *slots -=  msg_slots;
-        if (mei_write_message(dev, mei_hdr,
+        if (mei_write_message(dev, &mei_hdr,
                 dev->iamthif_msg_buf + dev->iamthif_msg_buf_index)) {
                         dev->iamthif_state = MEI_IAMTHIF_IDLE;
                         cl->status = -ENODEV;
@@ -470,10 +469,10 @@ int mei_amthif_irq_write_complete(struct mei_device *dev, s32 *slots,
         if (mei_flow_ctrl_reduce(dev, cl))
                 return -ENODEV;
 
-        dev->iamthif_msg_buf_index += mei_hdr->length;
+        dev->iamthif_msg_buf_index += mei_hdr.length;
         cl->status = 0;
 
-        if (mei_hdr->msg_complete) {
+        if (mei_hdr.msg_complete) {
                 dev->iamthif_state = MEI_IAMTHIF_FLOW_CONTROL;
                 dev->iamthif_flow_control_pending = true;
 
diff --git a/drivers/misc/mei/hbm.c b/drivers/misc/mei/hbm.c
index bc36c23cd2db..e9ba51d5a46c 100644
--- a/drivers/misc/mei/hbm.c
+++ b/drivers/misc/mei/hbm.c
@@ -67,21 +67,21 @@ bool mei_hbm_cl_addr_equal(struct mei_cl *cl, void *buf)
  */
 void mei_host_start_message(struct mei_device *dev)
 {
-        struct mei_msg_hdr *mei_hdr;
+        struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
         struct hbm_host_version_request *start_req;
         const size_t len = sizeof(struct hbm_host_version_request);
 
-        mei_hdr = mei_hbm_hdr(&dev->wr_msg_buf[0], len);
+        mei_hbm_hdr(mei_hdr, len);
 
         /* host start message */
-        start_req = (struct hbm_host_version_request *)&dev->wr_msg_buf[1];
+        start_req = (struct hbm_host_version_request *)dev->wr_msg.data;
         memset(start_req, 0, len);
         start_req->hbm_cmd = HOST_START_REQ_CMD;
         start_req->host_version.major_version = HBM_MAJOR_VERSION;
         start_req->host_version.minor_version = HBM_MINOR_VERSION;
 
         dev->recvd_msg = false;
-        if (mei_write_message(dev, mei_hdr, (unsigned char *)start_req)) {
+        if (mei_write_message(dev, mei_hdr, dev->wr_msg.data)) {
                 dev_dbg(&dev->pdev->dev, "write send version message to FW fail.\n");
                 dev->dev_state = MEI_DEV_RESETING;
                 mei_reset(dev, 1);
@@ -100,17 +100,17 @@ void mei_host_start_message(struct mei_device *dev)
  */
 void mei_host_enum_clients_message(struct mei_device *dev)
 {
-        struct mei_msg_hdr *mei_hdr;
+        struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
         struct hbm_host_enum_request *enum_req;
         const size_t len = sizeof(struct hbm_host_enum_request);
         /* enumerate clients */
-        mei_hdr = mei_hbm_hdr(&dev->wr_msg_buf[0], len);
+        mei_hbm_hdr(mei_hdr, len);
 
-        enum_req = (struct hbm_host_enum_request *) &dev->wr_msg_buf[1];
-        memset(enum_req, 0, sizeof(struct hbm_host_enum_request));
+        enum_req = (struct hbm_host_enum_request *)dev->wr_msg.data;
+        memset(enum_req, 0, len);
         enum_req->hbm_cmd = HOST_ENUM_REQ_CMD;
 
-        if (mei_write_message(dev, mei_hdr, (unsigned char *)enum_req)) {
+        if (mei_write_message(dev, mei_hdr, dev->wr_msg.data)) {
                 dev->dev_state = MEI_DEV_RESETING;
                 dev_dbg(&dev->pdev->dev, "write send enumeration request message to FW fail.\n");
                 mei_reset(dev, 1);
@@ -124,7 +124,7 @@ void mei_host_enum_clients_message(struct mei_device *dev)
 int mei_host_client_enumerate(struct mei_device *dev)
 {
 
-        struct mei_msg_hdr *mei_hdr;
+        struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
         struct hbm_props_request *prop_req;
         const size_t len = sizeof(struct hbm_props_request);
         unsigned long next_client_index;
@@ -146,8 +146,8 @@ int mei_host_client_enumerate(struct mei_device *dev)
         dev->me_clients[client_num].client_id = next_client_index;
         dev->me_clients[client_num].mei_flow_ctrl_creds = 0;
 
-        mei_hdr = mei_hbm_hdr(&dev->wr_msg_buf[0], len);
-        prop_req = (struct hbm_props_request *)&dev->wr_msg_buf[1];
+        mei_hbm_hdr(mei_hdr, len);
+        prop_req = (struct hbm_props_request *)dev->wr_msg.data;
 
         memset(prop_req, 0, sizeof(struct hbm_props_request));
 
@@ -155,7 +155,7 @@ int mei_host_client_enumerate(struct mei_device *dev)
         prop_req->hbm_cmd = HOST_CLIENT_PROPERTIES_REQ_CMD;
         prop_req->address = next_client_index;
 
-        if (mei_write_message(dev, mei_hdr, (unsigned char *) prop_req)) {
+        if (mei_write_message(dev, mei_hdr, dev->wr_msg.data)) {
                 dev->dev_state = MEI_DEV_RESETING;
                 dev_err(&dev->pdev->dev, "Properties request command failed\n");
                 mei_reset(dev, 1);
@@ -170,6 +170,27 @@ int mei_host_client_enumerate(struct mei_device *dev)
 }
 
 /**
+ * mei_hbm_stop_req_prepare - perpare stop request message
+ *
+ * @dev - mei device
+ * @mei_hdr - mei message header
+ * @data - hbm message body buffer
+ */
+static void mei_hbm_stop_req_prepare(struct mei_device *dev,
+                struct mei_msg_hdr *mei_hdr, unsigned char *data)
+{
+        struct hbm_host_stop_request *req =
+                        (struct hbm_host_stop_request *)data;
+        const size_t len = sizeof(struct hbm_host_stop_request);
+
+        mei_hbm_hdr(mei_hdr, len);
+
+        memset(req, 0, len);
+        req->hbm_cmd = HOST_STOP_REQ_CMD;
+        req->reason = DRIVER_STOP_REQUEST;
+}
+
+/**
  * mei_send_flow_control - sends flow control to fw.
  *
  * @dev: the device structure
@@ -179,17 +200,16 @@ int mei_host_client_enumerate(struct mei_device *dev)
  */
 int mei_send_flow_control(struct mei_device *dev, struct mei_cl *cl)
 {
-        struct mei_msg_hdr *mei_hdr;
-        unsigned char *buf = (unsigned char *)&dev->wr_msg_buf[1];
+        struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
         const size_t len = sizeof(struct hbm_flow_control);
 
-        mei_hdr = mei_hbm_hdr(&dev->wr_msg_buf[0], len);
-        mei_hbm_cl_hdr(cl, MEI_FLOW_CONTROL_CMD, buf, len);
+        mei_hbm_hdr(mei_hdr, len);
+        mei_hbm_cl_hdr(cl, MEI_FLOW_CONTROL_CMD, dev->wr_msg.data, len);
 
         dev_dbg(&dev->pdev->dev, "sending flow control host client = %d, ME client = %d\n",
                 cl->host_client_id, cl->me_client_id);
 
-        return mei_write_message(dev, mei_hdr, buf);
+        return mei_write_message(dev, mei_hdr, dev->wr_msg.data);
 }
 
 /**
@@ -202,14 +222,13 @@ int mei_send_flow_control(struct mei_device *dev, struct mei_cl *cl)
  */
 int mei_disconnect(struct mei_device *dev, struct mei_cl *cl)
 {
-        struct mei_msg_hdr *hdr;
-        unsigned char *buf = (unsigned char *)&dev->wr_msg_buf[1];
+        struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
         const size_t len = sizeof(struct hbm_client_connect_request);
 
-        hdr = mei_hbm_hdr(&dev->wr_msg_buf[0], len);
-        mei_hbm_cl_hdr(cl, CLIENT_DISCONNECT_REQ_CMD, buf, len);
+        mei_hbm_hdr(mei_hdr, len);
+        mei_hbm_cl_hdr(cl, CLIENT_DISCONNECT_REQ_CMD, dev->wr_msg.data, len);
 
-        return mei_write_message(dev, hdr, buf);
+        return mei_write_message(dev, mei_hdr, dev->wr_msg.data);
 }
 
 /**
@@ -222,14 +241,13 @@ int mei_disconnect(struct mei_device *dev, struct mei_cl *cl)
  */
 int mei_connect(struct mei_device *dev, struct mei_cl *cl)
 {
-        struct mei_msg_hdr *hdr;
-        unsigned char *buf = (unsigned char *)&dev->wr_msg_buf[1];
+        struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
         const size_t len = sizeof(struct hbm_client_connect_request);
 
-        hdr = mei_hbm_hdr(&dev->wr_msg_buf[0], len);
-        mei_hbm_cl_hdr(cl, CLIENT_CONNECT_REQ_CMD, buf, len);
+        mei_hbm_hdr(mei_hdr, len);
+        mei_hbm_cl_hdr(cl, CLIENT_CONNECT_REQ_CMD, dev->wr_msg.data, len);
 
-        return mei_write_message(dev, hdr, buf);
+        return mei_write_message(dev, mei_hdr,  dev->wr_msg.data);
 }
 
 /**
@@ -257,9 +275,9 @@ static void mei_client_disconnect_request(struct mei_device *dev,
                                 dev->iamthif_timer = 0;
 
                         /* prepare disconnect response */
-                        (void)mei_hbm_hdr((u32 *)&dev->wr_ext_msg.hdr, len);
+                        mei_hbm_hdr(&dev->wr_ext_msg.hdr, len);
                         mei_hbm_cl_hdr(cl, CLIENT_DISCONNECT_RES_CMD,
-                                         &dev->wr_ext_msg.data, len);
+                                         dev->wr_ext_msg.data, len);
                         break;
                 }
         }
@@ -284,7 +302,6 @@ void mei_hbm_dispatch(struct mei_device *dev, struct mei_msg_hdr *hdr)
         struct hbm_flow_control *flow_control;
         struct hbm_props_response *props_res;
         struct hbm_host_enum_response *enum_res;
-        struct hbm_host_stop_request *stop_req;
 
         /* read the message to our buffer */
         BUG_ON(hdr->length >= sizeof(dev->rd_msg_buf));
@@ -294,34 +311,27 @@ void mei_hbm_dispatch(struct mei_device *dev, struct mei_msg_hdr *hdr)
         switch (mei_msg->hbm_cmd) {
         case HOST_START_RES_CMD:
                 version_res = (struct hbm_host_version_response *)mei_msg;
-                if (version_res->host_version_supported) {
-                        dev->version.major_version = HBM_MAJOR_VERSION;
-                        dev->version.minor_version = HBM_MINOR_VERSION;
-                        if (dev->dev_state == MEI_DEV_INIT_CLIENTS &&
-                            dev->init_clients_state == MEI_START_MESSAGE) {
-                                dev->init_clients_timer = 0;
-                                mei_host_enum_clients_message(dev);
-                        } else {
-                                dev->recvd_msg = false;
-                                dev_dbg(&dev->pdev->dev, "IMEI reset due to received host start response bus message.\n");
-                                mei_reset(dev, 1);
-                                return;
-                        }
-                } else {
-                        u32 *buf = dev->wr_msg_buf;
-                        const size_t len = sizeof(struct hbm_host_stop_request);
-
+                if (!version_res->host_version_supported) {
                         dev->version = version_res->me_max_version;
+                        dev_dbg(&dev->pdev->dev, "version mismatch.\n");
 
-                        /* send stop message */
-                        hdr = mei_hbm_hdr(&buf[0], len);
-                        stop_req = (struct hbm_host_stop_request *)&buf[1];
-                        memset(stop_req, 0, len);
-                        stop_req->hbm_cmd = HOST_STOP_REQ_CMD;
-                        stop_req->reason = DRIVER_STOP_REQUEST;
+                        mei_hbm_stop_req_prepare(dev, &dev->wr_msg.hdr,
+                                                dev->wr_msg.data);
+                        mei_write_message(dev, &dev->wr_msg.hdr,
+                                        dev->wr_msg.data);
+                        return;
+                }
 
-                        mei_write_message(dev, hdr, (unsigned char *)stop_req);
-                        dev_dbg(&dev->pdev->dev, "version mismatch.\n");
+                dev->version.major_version = HBM_MAJOR_VERSION;
+                dev->version.minor_version = HBM_MINOR_VERSION;
+                if (dev->dev_state == MEI_DEV_INIT_CLIENTS &&
+                    dev->init_clients_state == MEI_START_MESSAGE) {
+                        dev->init_clients_timer = 0;
+                        mei_host_enum_clients_message(dev);
+                } else {
+                        dev->recvd_msg = false;
+                        dev_dbg(&dev->pdev->dev, "reset due to received hbm: host start\n");
+                        mei_reset(dev, 1);
                         return;
                 }
 
@@ -417,18 +427,10 @@ void mei_hbm_dispatch(struct mei_device *dev, struct mei_msg_hdr *hdr)
                 break;
 
         case ME_STOP_REQ_CMD:
-        {
-                /* prepare stop request: sent in next interrupt event */
 
-                const size_t len = sizeof(struct hbm_host_stop_request);
-
-                hdr = mei_hbm_hdr((u32 *)&dev->wr_ext_msg.hdr, len);
-                stop_req = (struct hbm_host_stop_request *)&dev->wr_ext_msg.data;
-                memset(stop_req, 0, len);
-                stop_req->hbm_cmd = HOST_STOP_REQ_CMD;
-                stop_req->reason = DRIVER_STOP_REQUEST;
+                mei_hbm_stop_req_prepare(dev, &dev->wr_ext_msg.hdr,
+                                        dev->wr_ext_msg.data);
                 break;
-        }
         default:
                 BUG();
                 break;
diff --git a/drivers/misc/mei/interrupt.c b/drivers/misc/mei/interrupt.c
index d4312a8e139a..9cbf148e02e0 100644
--- a/drivers/misc/mei/interrupt.c
+++ b/drivers/misc/mei/interrupt.c
@@ -469,25 +469,24 @@ static int _mei_irq_thread_ioctl(struct mei_device *dev, s32 *slots,
 static int mei_irq_thread_write_complete(struct mei_device *dev, s32 *slots,
                         struct mei_cl_cb *cb, struct mei_cl_cb *cmpl_list)
 {
-        struct mei_msg_hdr *mei_hdr;
+        struct mei_msg_hdr mei_hdr;
         struct mei_cl *cl = cb->cl;
         size_t len = cb->request_buffer.size - cb->buf_idx;
         size_t msg_slots = mei_data2slots(len);
 
-        mei_hdr = (struct mei_msg_hdr *)&dev->wr_msg_buf[0];
-        mei_hdr->host_addr = cl->host_client_id;
-        mei_hdr->me_addr = cl->me_client_id;
-        mei_hdr->reserved = 0;
+        mei_hdr.host_addr = cl->host_client_id;
+        mei_hdr.me_addr = cl->me_client_id;
+        mei_hdr.reserved = 0;
 
         if (*slots >= msg_slots) {
-                mei_hdr->length = len;
-                mei_hdr->msg_complete = 1;
+                mei_hdr.length = len;
+                mei_hdr.msg_complete = 1;
         /* Split the message only if we can write the whole host buffer */
         } else if (*slots == dev->hbuf_depth) {
                 msg_slots = *slots;
                 len = (*slots * sizeof(u32)) - sizeof(struct mei_msg_hdr);
-                mei_hdr->length = len;
-                mei_hdr->msg_complete = 0;
+                mei_hdr.length = len;
+                mei_hdr.msg_complete = 0;
         } else {
                 /* wait for next time the host buffer is empty */
                 return 0;
@@ -495,10 +494,10 @@ static int mei_irq_thread_write_complete(struct mei_device *dev, s32 *slots,
 
         dev_dbg(&dev->pdev->dev, "buf: size = %d idx = %lu\n",
                         cb->request_buffer.size, cb->buf_idx);
-        dev_dbg(&dev->pdev->dev, MEI_HDR_FMT, MEI_HDR_PRM(mei_hdr));
+        dev_dbg(&dev->pdev->dev, MEI_HDR_FMT, MEI_HDR_PRM(&mei_hdr));
 
         *slots -=  msg_slots;
-        if (mei_write_message(dev, mei_hdr,
+        if (mei_write_message(dev, &mei_hdr,
                         cb->request_buffer.data + cb->buf_idx)) {
                 cl->status = -ENODEV;
                 list_move_tail(&cb->list, &cmpl_list->list);
@@ -509,8 +508,8 @@ static int mei_irq_thread_write_complete(struct mei_device *dev, s32 *slots,
                 return -ENODEV;
 
         cl->status = 0;
-        cb->buf_idx += mei_hdr->length;
-        if (mei_hdr->msg_complete)
+        cb->buf_idx += mei_hdr.length;
+        if (mei_hdr.msg_complete)
                 list_move_tail(&cb->list, &dev->write_waiting_list.list);
 
         return 0;
diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index 107a820a6ba4..1ea331ac2463 100644
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -265,7 +265,13 @@ struct mei_device {
 
         unsigned char rd_msg_buf[MEI_RD_MSG_BUF_SIZE];  /* control messages */
         u32 rd_msg_hdr;
-        u32 wr_msg_buf[128];    /* used for control messages */
+
+        /* used for control messages */
+        struct {
+                struct mei_msg_hdr hdr;
+                unsigned char data[128];
+        } wr_msg;
+
         struct {
                 struct mei_msg_hdr hdr;
                 unsigned char data[4];  /* All HBM messages are 4 bytes */
@@ -459,15 +465,13 @@ void mei_disable_interrupts(struct mei_device *dev);
 
 void mei_hbm_dispatch(struct mei_device *dev, struct mei_msg_hdr *hdr);
 
-static inline struct mei_msg_hdr *mei_hbm_hdr(u32 *buf, size_t length)
+static inline void mei_hbm_hdr(struct mei_msg_hdr *hdr, size_t length)
 {
-        struct mei_msg_hdr *hdr = (struct mei_msg_hdr *)buf;
         hdr->host_addr = 0;
         hdr->me_addr = 0;
         hdr->length = length;
         hdr->msg_complete = 1;
         hdr->reserved = 0;
-        return hdr;
 }
 
 #define MEI_HDR_FMT "hdr:host=%02d me=%02d len=%d comp=%1d"
diff --git a/drivers/misc/mei/wd.c b/drivers/misc/mei/wd.c
index 9c3738a4eb08..3997a630847f 100644
--- a/drivers/misc/mei/wd.c
+++ b/drivers/misc/mei/wd.c
@@ -101,22 +101,21 @@ int mei_wd_host_init(struct mei_device *dev)
  */
 int mei_wd_send(struct mei_device *dev)
 {
-        struct mei_msg_hdr *hdr;
+        struct mei_msg_hdr hdr;
 
-        hdr = (struct mei_msg_hdr *) &dev->wr_msg_buf[0];
-        hdr->host_addr = dev->wd_cl.host_client_id;
-        hdr->me_addr = dev->wd_cl.me_client_id;
-        hdr->msg_complete = 1;
-        hdr->reserved = 0;
+        hdr.host_addr = dev->wd_cl.host_client_id;
+        hdr.me_addr = dev->wd_cl.me_client_id;
+        hdr.msg_complete = 1;
+        hdr.reserved = 0;
 
         if (!memcmp(dev->wd_data, mei_start_wd_params, MEI_WD_HDR_SIZE))
-                hdr->length = MEI_WD_START_MSG_SIZE;
+                hdr.length = MEI_WD_START_MSG_SIZE;
         else if (!memcmp(dev->wd_data, mei_stop_wd_params, MEI_WD_HDR_SIZE))
-                hdr->length = MEI_WD_STOP_MSG_SIZE;
+                hdr.length = MEI_WD_STOP_MSG_SIZE;
         else
                 return -EINVAL;
 
-        return mei_write_message(dev, hdr, dev->wd_data);
+        return mei_write_message(dev, &hdr, dev->wd_data);
 }
 
 /**