Merge pull request #165 from lechndo/bug_#161_STM32_CRC_DMA_size_limit

Fix #161: STM32 LLD CRCv1 large data bug in DMA mode

2 files changed, 21 insertions, 5 deletions

diff --git a/os/hal/ports/STM32/LLD/CRCv1/hal_crc_lld.c b/os/hal/ports/STM32/LLD/CRCv1/hal_crc_lld.c
index 701b87d..180a383 100755
--- a/os/hal/ports/STM32/LLD/CRCv1/hal_crc_lld.c
+++ b/os/hal/ports/STM32/LLD/CRCv1/hal_crc_lld.c
@@ -121,9 +121,14 @@ static void crc_lld_serve_interrupt(CRCDriver *crcp, uint32_t flags) {
   /* Stop everything.*/
   dmaStreamDisable(crcp->dma);
 
-  /* Portable CRC ISR code defined in the high level driver, note, it is
-     a macro.*/
-  _crc_isr_code(crcp, crcp->crc->DR ^ crcp->config->final_val);
+  if (crcp->rem_data_size) {
+    /* Start DMA follow up transfer for next data chunk */
+    crc_lld_start_calc(crcp, crcp->rem_data_size,
+      (const void *)crcp->dma->channel->CPAR+0xffff);
+  } else {
+    /* Portable CRC ISR code defined in the high level driver, note, it is a macro.*/
+    _crc_isr_code(crcp, crcp->crc->DR ^ crcp->config->final_val);
+  }
 }
 #endif
 
@@ -308,12 +313,17 @@ uint32_t crc_lld_calc(CRCDriver *crcp, size_t n, const void *buf) {
 
 #if CRC_USE_DMA == TRUE
 void crc_lld_start_calc(CRCDriver *crcp, size_t n, const void *buf) {
+  /* The STM32 DMA can only handle max 65535 bytes per transfer
+   * because it's data count register has only 16 bit. */
+  size_t sz = (n > 0xffff) ? 0xffff : n;
+  crcp->rem_data_size = n-sz;
+
   dmaStreamSetPeripheral(crcp->dma, buf);
   dmaStreamSetMemory0(crcp->dma, &crcp->crc->DR);
 #if STM32_CRC_PROGRAMMABLE == TRUE
-  dmaStreamSetTransactionSize(crcp->dma, n);
+  dmaStreamSetTransactionSize(crcp->dma, sz);
 #else
-  dmaStreamSetTransactionSize(crcp->dma, (n / 4));
+  dmaStreamSetTransactionSize(crcp->dma, (sz / 4));
 #endif
   dmaStreamSetMode(crcp->dma, crcp->dmamode);
 
diff --git a/os/hal/ports/STM32/LLD/CRCv1/hal_crc_lld.h b/os/hal/ports/STM32/LLD/CRCv1/hal_crc_lld.h
index 213d346..e879103 100644
--- a/os/hal/ports/STM32/LLD/CRCv1/hal_crc_lld.h
+++ b/os/hal/ports/STM32/LLD/CRCv1/hal_crc_lld.h
@@ -203,6 +203,12 @@ struct CRCDriver {
    */
   thread_reference_t        thread;
   /**
+   * @brief   Remaining data size.
+   * @note    The DMA can handle only 65535 bytes per transfer because
+   *            it's data count register is only 16 bits wide.
+   */
+  size_t rem_data_size;
+  /**
    * @brief CRC DMA stream
    */
   const stm32_dma_stream_t  *dma;