[stm32][drv_serial] 修复recv_len意外为负（即很大正数）的问题

mysterywolf · mysterywolf · commit 76885ca90831 · 2022-08-04T22:51:34.000-04:00
#6106 #4467 (comment)
diff --git a/bsp/stm32/libraries/HAL_Drivers/drv_usart.c b/bsp/stm32/libraries/HAL_Drivers/drv_usart.c
@@ -489,7 +489,7 @@ static void dma_isr(struct rt_serial_device *serial)
         }
         else
         {
-            recv_len = recv_total_index - uart->dma_rx.last_index;
+            recv_len = serial->config.bufsz - uart->dma_rx.last_index + recv_total_index;
         }
         uart->dma_rx.last_index = recv_total_index;
         rt_hw_interrupt_enable(level);

Original file line number	Diff line number	Diff line change
`@@ -489,7 +489,7 @@ static void dma_isr(struct rt_serial_device *serial)`
`489`	`489`	`}`
`490`	`490`	`else`
`491`	`491`	`{`
`492`		`- recv_len = recv_total_index - uart->dma_rx.last_index;`
	`492`	`+ recv_len = serial->config.bufsz - uart->dma_rx.last_index + recv_total_index;`
`493`	`493`	`}`
`494`	`494`	`uart->dma_rx.last_index = recv_total_index;`
`495`	`495`	`rt_hw_interrupt_enable(level);`