[bsp][stm32][spi] 优化DMA数据非字节对齐的处理流程

Author: wdfk-prog

bsp/stm32/libraries/HAL_Drivers/drv_spi.c

@@ -341,35 +341,50 @@ static rt_ssize_t spixfer(struct rt_spi_device *device, struct rt_spi_message *m
             recv_buf = (rt_uint8_t *)message->recv_buf + already_send_length;
         }
 
-#if defined(SOC_SERIES_STM32H7) || defined(SOC_SERIES_STM32F7)
-        rt_uint32_t* dma_buf = RT_NULL;
-        if ((spi_drv->spi_dma_flag & SPI_USING_TX_DMA_FLAG) && (spi_drv->spi_dma_flag & SPI_USING_RX_DMA_FLAG) && (send_length >= DMA_TRANS_MIN_LEN))
+        rt_uint32_t* dma_aligned_buffer = RT_NULL;
+        rt_uint32_t* p_txrx_buffer = RT_NULL;
+
+        if ((spi_drv->spi_dma_flag & SPI_USING_TX_DMA_FLAG) && (send_length >= DMA_TRANS_MIN_LEN))
         {
-            dma_buf = (rt_uint32_t *)rt_malloc_align(send_length,32);
-            if(send_buf)
+#if defined(SOC_SERIES_STM32H7) || defined(SOC_SERIES_STM32F7)
+            if (RT_IS_ALIGN((rt_uint32_t)send_buf, 32)) /* aligned with 32 bytes? */
             {
-                rt_memcpy(dma_buf, send_buf, send_length);
+                p_txrx_buffer = (rt_uint32_t *)send_buf; /* send_buf aligns with 32 bytes, no more operations */
             }
             else
             {
-                rt_memset(dma_buf, 0xFF, send_length);
+                /* send_buf doesn't align with 32 bytes, so creat a cache buffer with 32 bytes aligned */
+                dma_aligned_buffer = (rt_uint32_t *)rt_malloc_align(send_length, 32);
+                rt_memcpy(dma_aligned_buffer, send_buf, send_length);
+                p_txrx_buffer = dma_aligned_buffer;
+            }
+            rt_hw_cpu_dcache_ops(RT_HW_CACHE_FLUSH, dma_aligned_buffer, send_length);
+#else
+            if (RT_IS_ALIGN((rt_uint32_t)send_buf, 4)) /* aligned with 4 bytes? */
+            {
+                p_txrx_buffer = (rt_uint32_t *)send_buf; /* send_buf aligns with 4 bytes, no more operations */
+            }
+            else
+            {
+                /* send_buf doesn't align with 4 bytes, so creat a cache buffer with 4 bytes aligned */
+                dma_aligned_buffer = (rt_uint32_t *)rt_malloc(send_length); /* aligned with RT_ALIGN_SIZE (8 bytes by default) */
+                rt_memcpy(dma_aligned_buffer, send_buf, send_length);
+                p_txrx_buffer = dma_aligned_buffer;
             }
-            rt_hw_cpu_dcache_ops(RT_HW_CACHE_FLUSH, dma_buf, send_length);
-            state = HAL_SPI_TransmitReceive_DMA(spi_handle, (uint8_t *)dma_buf, (uint8_t *)dma_buf, send_length);
-        }
-        else
 #endif /* SOC_SERIES_STM32H7 || SOC_SERIES_STM32F7 */
+        }
+
         /* start once data exchange in DMA mode */
         if (message->send_buf && message->recv_buf)
         {
             if ((spi_drv->spi_dma_flag & SPI_USING_TX_DMA_FLAG) && (spi_drv->spi_dma_flag & SPI_USING_RX_DMA_FLAG) && (send_length >= DMA_TRANS_MIN_LEN))
             {
-                state = HAL_SPI_TransmitReceive_DMA(spi_handle, (uint8_t *)send_buf, (uint8_t *)recv_buf, send_length);
+                state = HAL_SPI_TransmitReceive_DMA(spi_handle, (uint8_t *)p_txrx_buffer, (uint8_t *)p_txrx_buffer, send_length);
             }
             else if ((spi_drv->spi_dma_flag & SPI_USING_TX_DMA_FLAG) && (send_length >= DMA_TRANS_MIN_LEN))
             {
                 /* same as Tx ONLY. It will not receive SPI data any more. */
-                state = HAL_SPI_Transmit_DMA(spi_handle, (uint8_t *)send_buf, send_length);
+                state = HAL_SPI_Transmit_DMA(spi_handle, (uint8_t *)p_txrx_buffer, send_length);
             }
             else if ((spi_drv->spi_dma_flag & SPI_USING_RX_DMA_FLAG) && (send_length >= DMA_TRANS_MIN_LEN))
             {
@@ -386,7 +401,7 @@ static rt_ssize_t spixfer(struct rt_spi_device *device, struct rt_spi_message *m
         {
             if ((spi_drv->spi_dma_flag & SPI_USING_TX_DMA_FLAG) && (send_length >= DMA_TRANS_MIN_LEN))
             {
-                state = HAL_SPI_Transmit_DMA(spi_handle, (uint8_t *)send_buf, send_length);
+                state = HAL_SPI_Transmit_DMA(spi_handle, (uint8_t *)p_txrx_buffer, send_length);
             }
             else
             {
@@ -404,7 +419,7 @@ static rt_ssize_t spixfer(struct rt_spi_device *device, struct rt_spi_message *m
             rt_memset((uint8_t *)recv_buf, 0xff, send_length);
             if ((spi_drv->spi_dma_flag & SPI_USING_RX_DMA_FLAG) && (send_length >= DMA_TRANS_MIN_LEN))
             {
-                state = HAL_SPI_Receive_DMA(spi_handle, (uint8_t *)recv_buf, send_length);
+                state = HAL_SPI_Receive_DMA(spi_handle, (uint8_t *)p_txrx_buffer, send_length);
             }
             else
             {
@@ -449,17 +464,21 @@ static rt_ssize_t spixfer(struct rt_spi_device *device, struct rt_spi_message *m
             while (HAL_SPI_GetState(spi_handle) != HAL_SPI_STATE_READY);
         }
 
-#if defined(SOC_SERIES_STM32H7) || defined(SOC_SERIES_STM32F7)
-        if(dma_buf)
+        if(dma_aligned_buffer != RT_NULL) /* re-aligned, so need to copy the data to recv_buf */
         {
-            if(recv_buf)
+            if(recv_buf != RT_NULL)
             {
-                rt_hw_cpu_dcache_ops(RT_HW_CACHE_INVALIDATE, dma_buf, send_length);
-                rt_memcpy(recv_buf, dma_buf,send_length);
+#if defined(SOC_SERIES_STM32H7) || defined(SOC_SERIES_STM32F7)
+                rt_hw_cpu_dcache_ops(RT_HW_CACHE_INVALIDATE, p_txrx_buffer, send_length);
+#endif /* SOC_SERIES_STM32H7 || SOC_SERIES_STM32F7 */
+                rt_memcpy(recv_buf, p_txrx_buffer, send_length);
             }
-            rt_free_align(dma_buf);
-        }
+#if defined(SOC_SERIES_STM32H7) || defined(SOC_SERIES_STM32F7)
+            rt_free_align(dma_aligned_buffer);
+#else
+            rt_free(dma_aligned_buffer);
 #endif /* SOC_SERIES_STM32H7 || SOC_SERIES_STM32F7 */
+        }
     }
 
     if (message->cs_release && !(device->config.mode & RT_SPI_NO_CS) && (device->cs_pin != PIN_NONE))