soc/tegra: bpmp: Check BPMP response return code

Add checks for the return code in BPMP response messages.

Signed-off-by: Timo Alho <[e-mail]>
Acked-by: Jon Hunter <[e-mail]>
Signed-off-by: Thierry Reding <[e-mail]>

drivers/soc/tegra/powergate-bpmp.c

···
 {
 	struct mrq_pg_request request;
 	struct tegra_bpmp_message msg;
+	int err;
 
 	memset(&request, 0, sizeof(request));
 	request.cmd = CMD_PG_SET_STATE;
···
 	msg.tx.data = &request;
 	msg.tx.size = sizeof(request);
 
-	return tegra_bpmp_transfer(bpmp, &msg);
+	err = tegra_bpmp_transfer(bpmp, &msg);
+	if (err < 0)
+		return err;
+	else if (msg.rx.ret < 0)
+		return -EINVAL;
+
+	return 0;
 }
 
 static int tegra_bpmp_powergate_get_state(struct tegra_bpmp *bpmp,
···
 	err = tegra_bpmp_transfer(bpmp, &msg);
 	if (err < 0)
 		return PG_STATE_OFF;
+	else if (msg.rx.ret < 0)
+		return -EINVAL;
 
 	return response.get_state.state;
 }
···
 	err = tegra_bpmp_transfer(bpmp, &msg);
 	if (err < 0)
 		return err;
+	else if (msg.rx.ret < 0)
+		return -EINVAL;
 
 	return response.get_max_id.max_id;
 }
···
 	msg.rx.size = sizeof(response);
 
 	err = tegra_bpmp_transfer(bpmp, &msg);
-	if (err < 0)
+	if (err < 0 || msg.rx.ret < 0)
 		return NULL;
 
 	return kstrdup(response.get_name.name, GFP_KERNEL);