PSP TEE driver update and bug fixes

index 5e697a90ea7f..910b71df2aef 100644
@@ -5,7 +5,7 @@
  * Author: Rijo Thomas <[email protected]>
  * Author: Devaraj Rangasamy <[email protected]>
  *
- * Copyright 2019 Advanced Micro Devices, Inc.
+ * Copyright (C) 2019,2021 Advanced Micro Devices, Inc.
  */
 
 #include <linux/types.h>

@@ -309,14 +309,14 @@ static int tee_wait_cmd_completion(struct psp_tee_device *tee,
 				   struct tee_ring_cmd *resp,
 				   unsigned int timeout)
 {
-	/* ~5ms sleep per loop => nloop = timeout * 200 */
-	int nloop = timeout * 200;
+	/* ~1ms sleep per loop => nloop = timeout * 1000 */
+	int nloop = timeout * 1000;
 
 	while (--nloop) {
 		if (resp->cmd_state == TEE_CMD_STATE_COMPLETED)
 			return 0;
 
-		usleep_range(5000, 5100);
+		usleep_range(1000, 1100);
 	}
 
 	dev_err(tee->dev, "tee: command 0x%x timed out, disabling PSP\n",

index 910b71df2aef..8cade4775115 100644
@@ -36,6 +36,7 @@ static int tee_alloc_ring(struct psp_tee_device *tee, int ring_size)
 	if (!start_addr)
 		return -ENOMEM;
 
+	memset(start_addr, 0x0, ring_size);
 	rb_mgr->ring_start = start_addr;
 	rb_mgr->ring_size = ring_size;
 	rb_mgr->ring_pa = __psp_pa(start_addr);

@@ -244,41 +245,54 @@ static int tee_submit_cmd(struct psp_tee_device *tee, enum tee_cmd_id cmd_id,
 			  void *buf, size_t len, struct tee_ring_cmd **resp)
 {
 	struct tee_ring_cmd *cmd;
-	u32 rptr, wptr;
 	int nloop = 1000, ret = 0;
+	u32 rptr;
 
 	*resp = NULL;
 
 	mutex_lock(&tee->rb_mgr.mutex);
 
-	wptr = tee->rb_mgr.wptr;
-
-	/* Check if ring buffer is full */
+	/* Loop until empty entry found in ring buffer */
 	do {
+		/* Get pointer to ring buffer command entry */
+		cmd = (struct tee_ring_cmd *)
+			(tee->rb_mgr.ring_start + tee->rb_mgr.wptr);
+
 		rptr = ioread32(tee->io_regs + tee->vdata->ring_rptr_reg);
 
-		if (!(wptr + sizeof(struct tee_ring_cmd) == rptr))
+		/* Check if ring buffer is full or command entry is waiting
+		 * for response from TEE
+		 */
+		if (!(tee->rb_mgr.wptr + sizeof(struct tee_ring_cmd) == rptr ||
+		      cmd->flag == CMD_WAITING_FOR_RESPONSE))
 			break;
 
-		dev_info(tee->dev, "tee: ring buffer full. rptr = %u wptr = %u\n",
-			 rptr, wptr);
+		dev_dbg(tee->dev, "tee: ring buffer full. rptr = %u wptr = %u\n",
+			rptr, tee->rb_mgr.wptr);
 
-		/* Wait if ring buffer is full */
+		/* Wait if ring buffer is full or TEE is processing data */
 		mutex_unlock(&tee->rb_mgr.mutex);
 		schedule_timeout_interruptible(msecs_to_jiffies(10));
 		mutex_lock(&tee->rb_mgr.mutex);
 
 	} while (--nloop);
 
-	if (!nloop && (wptr + sizeof(struct tee_ring_cmd) == rptr)) {
-		dev_err(tee->dev, "tee: ring buffer full. rptr = %u wptr = %u\n",
-			rptr, wptr);
+	if (!nloop &&
+	    (tee->rb_mgr.wptr + sizeof(struct tee_ring_cmd) == rptr ||
+	     cmd->flag == CMD_WAITING_FOR_RESPONSE)) {
+		dev_err(tee->dev, "tee: ring buffer full. rptr = %u wptr = %u response flag %u\n",
+			rptr, tee->rb_mgr.wptr, cmd->flag);
 		ret = -EBUSY;
 		goto unlock;
 	}
 
-	/* Pointer to empty data entry in ring buffer */
-	cmd = (struct tee_ring_cmd *)(tee->rb_mgr.ring_start + wptr);
+	/* Do not submit command if PSP got disabled while processing any
+	 * command in another thread
+	 */
+	if (psp_dead == true) {
+		ret = -EBUSY;
+		goto unlock;
+	}
 
 	/* Write command data into ring buffer */
 	cmd->cmd_id = cmd_id;

@@ -286,6 +300,9 @@ static int tee_submit_cmd(struct psp_tee_device *tee, enum tee_cmd_id cmd_id,
 	memset(&cmd->buf[0], 0, sizeof(cmd->buf));
 	memcpy(&cmd->buf[0], buf, len);
 
+	/* Indicate driver is waiting for response */
+	cmd->flag = CMD_WAITING_FOR_RESPONSE;
+
 	/* Update local copy of write pointer */
 	tee->rb_mgr.wptr += sizeof(struct tee_ring_cmd);
 	if (tee->rb_mgr.wptr >= tee->rb_mgr.ring_size)

@@ -353,12 +370,16 @@ int psp_tee_process_cmd(enum tee_cmd_id cmd_id, void *buf, size_t len,
 		return ret;
 
 	ret = tee_wait_cmd_completion(tee, resp, TEE_DEFAULT_TIMEOUT);
-	if (ret)
+	if (ret) {
+		resp->flag = CMD_RESPONSE_TIMEDOUT;
 		return ret;
+	}
 
 	memcpy(buf, &resp->buf[0], len);
 	*status = resp->status;
 
+	resp->flag = CMD_RESPONSE_COPIED;
+
 	return 0;
 }
 EXPORT_SYMBOL(psp_tee_process_cmd);

index f09960112115..49d26158b71e 100644
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT */
 /*
- * Copyright 2019 Advanced Micro Devices, Inc.
+ * Copyright (C) 2019,2021 Advanced Micro Devices, Inc.
  *
  * Author: Rijo Thomas <[email protected]>
  * Author: Devaraj Rangasamy <[email protected]>

@@ -18,7 +18,7 @@
 #include <linux/mutex.h>
 
 #define TEE_DEFAULT_TIMEOUT		10
-#define MAX_BUFFER_SIZE			992
+#define MAX_BUFFER_SIZE			988
 
 /**
  * enum tee_ring_cmd_id - TEE interface commands for ring buffer configuration

@@ -81,6 +81,20 @@ enum tee_cmd_state {
 	TEE_CMD_STATE_COMPLETED,
 };
 
+/**
+ * enum cmd_resp_state - TEE command's response status maintained by driver
+ * @CMD_RESPONSE_INVALID:      initial state when no command is written to ring
+ * @CMD_WAITING_FOR_RESPONSE:  driver waiting for response from TEE
+ * @CMD_RESPONSE_TIMEDOUT:     failed to get response from TEE
+ * @CMD_RESPONSE_COPIED:       driver has copied response from TEE
+ */
+enum cmd_resp_state {
+	CMD_RESPONSE_INVALID,
+	CMD_WAITING_FOR_RESPONSE,
+	CMD_RESPONSE_TIMEDOUT,
+	CMD_RESPONSE_COPIED,
+};
+
 /**
  * struct tee_ring_cmd - Structure of the command buffer in TEE ring
  * @cmd_id:      refers to &enum tee_cmd_id. Command id for the ring buffer

@@ -91,6 +105,7 @@ enum tee_cmd_state {
  * @pdata:       private data (currently unused)
  * @res1:        reserved region
  * @buf:         TEE command specific buffer
+ * @flag:	 refers to &enum cmd_resp_state
  */
 struct tee_ring_cmd {
 	u32 cmd_id;

@@ -100,6 +115,7 @@ struct tee_ring_cmd {
 	u64 pdata;
 	u32 res1[2];
 	u8 buf[MAX_BUFFER_SIZE];
+	u32 flag;
 
 	/* Total size: 1024 bytes */
 } __packed;