From f913bfa8b93ce5cd8ae06b14ad9ae180574ed5be Mon Sep 17 00:00:00 2001
From: "shenyang.wang" <enginexpert@163.com>
Date: Thu, 15 Aug 2024 15:42:41 +0800
Subject: [PATCH] =?UTF-8?q?=E4=B8=B2=E5=8F=A3=E4=BD=BF=E7=94=A8DMA?=
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---
 components/drivers/serial/serial_v2.c | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/components/drivers/serial/serial_v2.c b/components/drivers/serial/serial_v2.c
index d7576dbed8..3a41f11caf 100644
--- a/components/drivers/serial/serial_v2.c
+++ b/components/drivers/serial/serial_v2.c
@@ -263,23 +263,18 @@ static rt_ssize_t rt_serial_update_write_index(struct rt_ringbuffer  *rb,
     rt_uint16_t size;
     RT_ASSERT(rb != RT_NULL);
 
-    /* whether has enough space */
+    /* get available space */
     size = rt_ringbuffer_space_len(rb);
 
-    /* no space, drop some data */
-    if (size < write_size)
-    {
-        write_size = size;
-#if !defined(RT_USING_ULOG) || defined(ULOG_USING_ISR_LOG)
-        LOG_W("The serial buffer (len %d) is overflow.", rb->buffer_size);
-#endif
-    }
-
     if (rb->buffer_size - rb->write_index > write_size)
     {
         /* this should not cause overflow because there is enough space for
          * length of data in current mirror */
         rb->write_index += write_size;
+        if (write_size > size)
+        {
+            rb->read_index = rb->write_index;
+        }
         return write_size;
     }
 
@@ -287,6 +282,14 @@ static rt_ssize_t rt_serial_update_write_index(struct rt_ringbuffer  *rb,
     rb->write_mirror = ~rb->write_mirror;
     rb->write_index = write_size - (rb->buffer_size - rb->write_index);
 
+    if (write_size > size)
+    {
+        /* available space is insufficient,it will overwrite the existing data
+         * in the ring buffer.*/
+        if (rb->write_index <= rb->read_index)
+            rb->read_mirror = ~rb->read_mirror;
+        rb->read_index = rb->write_index;
+    }
     return write_size;
 }
 
-- 
Gitee