soc: qcom: spss_utils: handle ssr after fota

After SPU's firmware was updated,
prevent SSR from happening until getting
a message from userspace that update is finished.
Need to Avoid SSR because PIL would load old images from /firmware_mnt.

Change-Id: I4b07e2e886e26a928faeae0c6f4f790dd01c645f
Signed-off-by: Dan Bar-On <dbaron@codeaurora.org>

drivers/soc/qcom/spcom.c

@@ -259,6 +259,9 @@ static struct spcom_channel *spcom_find_channel_by_name(const char *name);
 static int spcom_register_rpmsg_drv(struct spcom_channel *ch);
 static int spcom_unregister_rpmsg_drv(struct spcom_channel *ch);
 
+/* PIL's original SSR function*/
+int (*desc_powerup)(const struct subsys_desc *) = NULL;
+
 /**
  * spcom_is_channel_open() - channel is open on this side.
  *
@@ -604,6 +607,24 @@ static int spcom_local_powerup(const struct subsys_desc *subsys)
 	return 0;
 }
 
+/**
+ * spcom_local_powerup_after_fota() - SSR is not allowed after FOTA -
+ * might cause cryptographic erase. Reset the device
+ *
+ * @subsys: subsystem descriptor.
+ *
+ * Return: 0 on successful operation, negative value otherwise.
+ */
+static int spcom_local_powerup_after_fota(const struct subsys_desc *subsys)
+{
+	(void)subsys;
+
+	pr_err("SSR after firmware update before calling IAR update - panic\n");
+	panic("SSR after SPU firmware update\n");
+
+	return 0;
+}
+
 /**
  * spcom_handle_restart_sp_command() - Handle Restart SP command from
  * user space.
@@ -618,7 +639,6 @@ static int spcom_handle_restart_sp_command(void *cmd_buf, int cmd_size)
 	void *subsystem_get_retval = NULL;
 	struct spcom_user_restart_sp_command *cmd = cmd_buf;
 	struct subsys_desc *desc_p = NULL;
-	int (*desc_powerup)(const struct subsys_desc *) = NULL;
 
 	if (!cmd) {
 		pr_err("NULL cmd_buf\n");
@@ -672,8 +692,14 @@ static int spcom_handle_restart_sp_command(void *cmd_buf, int cmd_size)
 	}
 
 	if (cmd->arg) {
-		/* Reset the PIL subsystem power up function */
+
-		desc_p->powerup = desc_powerup;
+		/* SPU got firmware update. Don't allow SSR*/
+		if (cmd->is_updated) {
+			desc_p->powerup = spcom_local_powerup_after_fota;
+		} else {
+			/* Reset the PIL subsystem power up function */
+			desc_p->powerup = desc_powerup;
+		}
 	}
 	pr_debug("restart - PIL FW loading process is complete\n");
 	return 0;
@@ -1146,6 +1172,41 @@ static int spcom_handle_unlock_ion_buf_command(struct spcom_channel *ch,
 	return 0;
 }
 
+/**
+ * spcom_handle_enable_ssr_command() - Handle user space request to enable ssr
+ *
+ * After FOTA SSR is disabled until IAR update occurs.
+ * Then - enable SSR again
+ *
+ * Return: size in bytes on success, negative value on failure.
+ */
+static int spcom_handle_enable_ssr_command(void)
+{
+	struct subsys_desc *desc_p = NULL;
+	void *subsystem_get_retval = find_subsys_device("spss");
+
+	if (!subsystem_get_retval) {
+		pr_err("restart - no device\n");
+		return -ENODEV;
+	}
+
+	desc_p = *(struct subsys_desc **)subsystem_get_retval;
+	if (!desc_p) {
+		pr_err("restart - no device\n");
+		return -ENODEV;
+	}
+
+	if (!desc_powerup) {
+		pr_err("no original SSR function\n");
+		return -ENODEV;
+	}
+
+	desc_p->powerup = desc_powerup;
+	pr_info("SSR is enabled after FOTA\n");
+
+	return 0;
+}
+
 /**
  * spcom_handle_write() - Handle user space write commands.
  *
@@ -1174,7 +1235,8 @@ static int spcom_handle_write(struct spcom_channel *ch,
 	pr_debug("cmd_id [0x%x]\n", cmd_id);
 
 	if (!ch && cmd_id != SPCOM_CMD_CREATE_CHANNEL
-			&& cmd_id != SPCOM_CMD_RESTART_SP) {
+			&& cmd_id != SPCOM_CMD_RESTART_SP
+			&& cmd_id != SPCOM_CMD_ENABLE_SSR) {
 		pr_err("channel context is null\n");
 		return -EINVAL;
 	}
@@ -1210,6 +1272,9 @@ static int spcom_handle_write(struct spcom_channel *ch,
 	case SPCOM_CMD_RESTART_SP:
 		ret = spcom_handle_restart_sp_command(buf, buf_size);
 		break;
+	case SPCOM_CMD_ENABLE_SSR:
+		ret = spcom_handle_enable_ssr_command();
+		break;
 	default:
 		pr_err("Invalid Command Id [0x%x]\n", (int) cmd->cmd_id);
 		ret = -EINVAL;
@@ -1964,7 +2029,7 @@ static int spcom_create_channel_chardev(const char *name, bool is_sharable)
 	if (ret != 0)
 		pr_err("can't unregister rpmsg drv %d\n", ret);
 exit_destroy_channel:
-	// empty channel leaves free slot for next time
+	/* empty channel leaves free slot for next time*/
 	mutex_lock(&ch->lock);
 	memset(ch->name, 0, SPCOM_CHANNEL_NAME_SIZE);
 	mutex_unlock(&ch->lock);
@@ -2293,7 +2358,7 @@ static void spcom_rpdev_remove(struct rpmsg_device *rpdev)
 	}
 
 	mutex_lock(&ch->lock);
-	// unlock all ion buffers of sp_kernel channel
+	/* unlock all ion buffers of sp_kernel channel*/
 	if (strcmp(ch->name, "sp_kernel") == 0) {
 		for (i = 0; i < ARRAY_SIZE(ch->dmabuf_handle_table); i++) {
 			if (ch->dmabuf_handle_table[i] != NULL) {

include/uapi/linux/spcom.h

@@ -50,9 +50,14 @@ enum spcom_cmd_id {
 	SPCOM_CMD_UNLOCK_ION_BUF = 0x554C434B, /* "ULCK" = 0x4C4F434B */
 	SPCOM_CMD_FSSR		= 0x46535352, /* "FSSR" = 0x46535352 */
 	SPCOM_CMD_CREATE_CHANNEL = 0x43524554, /* "CRET" = 0x43524554 */
+
+#define SPCOM_CMD_ENABLE_SSR \
+	SPCOM_CMD_ENABLE_SSR
+	SPCOM_CMD_ENABLE_SSR     = 0x45535352,   /* "ESSR" =0x45535352*/
+
 #define SPCOM_CMD_RESTART_SP \
 	SPCOM_CMD_RESTART_SP
-	SPCOM_CMD_RESTART_SP    = 0x52535452, /* "RSTR" = 0x52535452 */
+	SPCOM_CMD_RESTART_SP         = 0x52535452,   /* "RSTR" = 0x52535452 */
 };
 
 /*
@@ -94,6 +99,8 @@ struct spcom_user_create_channel_command {
 struct spcom_user_restart_sp_command {
 	enum spcom_cmd_id cmd_id;
 	uint32_t arg;
+#define SPCOM_IS_UPDATED_SUPPORETED
+	uint32_t is_updated;
 } __packed;
 
 /* maximum ION buf for send-modfied-command */