From 844094dc44cb49b534191cde1d60a05b7d6e00d9 Mon Sep 17 00:00:00 2001
From: spacecoaster <spacecoaster@35acf78f-673a-0410-8e92-d51de3d6d3f4>
Date: Tue, 23 Sep 2014 16:46:14 +0000
Subject: [PATCH] [KINETIS] K20x SPI use separate rx/tx dummy bytes.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@7310 35acf78f-673a-0410-8e92-d51de3d6d3f4
---
 os/hal/ports/KINETIS/K20x/spi_lld.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/os/hal/ports/KINETIS/K20x/spi_lld.c b/os/hal/ports/KINETIS/K20x/spi_lld.c
index b06dceb15..77d8f5e65 100644
--- a/os/hal/ports/KINETIS/K20x/spi_lld.c
+++ b/os/hal/ports/KINETIS/K20x/spi_lld.c
@@ -70,12 +70,15 @@ SPIDriver SPID1;
 /* Driver local variables and types.                                         */
 /*===========================================================================*/
 
+/* Use a dummy byte as the source/destination when a buffer is not provided */
+/* Note: The MMC driver relies on 0xFF being sent for dummy bytes. */
+static volatile uint16_t dmaRxDummy;
+static uint16_t dmaTxDummy = 0xFFFF;
+
 /*===========================================================================*/
 /* Driver local functions.                                                   */
 /*===========================================================================*/
 
-volatile uint8_t dmaDummy;
-
 static void spi_start_xfer(SPIDriver *spip, bool polling)
 {
   /*
@@ -91,15 +94,12 @@ static void spi_start_xfer(SPIDriver *spip, bool polling)
     spip->spi->RSER = SPIx_RSER_RFDF_DIRS | SPIx_RSER_RFDF_RE |
         SPIx_RSER_TFFF_RE | SPIx_RSER_TFFF_DIRS;
 
-    /* Use dmaDummy as the source/destination when a buffer is not provided */
-    dmaDummy = 0;
-
     /* Configure RX DMA */
     if (spip->rxbuf) {
       DMA->TCD[KINETIS_SPI0_RX_DMA_CHANNEL].DADDR = (uint32_t)spip->rxbuf;
       DMA->TCD[KINETIS_SPI0_RX_DMA_CHANNEL].DOFF = spip->word_size;
     } else {
-      DMA->TCD[KINETIS_SPI0_RX_DMA_CHANNEL].DADDR = (uint32_t)&dmaDummy;
+      DMA->TCD[KINETIS_SPI0_RX_DMA_CHANNEL].DADDR = (uint32_t)&dmaRxDummy;
       DMA->TCD[KINETIS_SPI0_RX_DMA_CHANNEL].DOFF = 0;
     }
     DMA->TCD[KINETIS_SPI0_RX_DMA_CHANNEL].BITER_ELINKNO = spip->count;
@@ -113,7 +113,7 @@ static void spi_start_xfer(SPIDriver *spip, bool polling)
       DMA->TCD[KINETIS_SPI0_TX_DMA_CHANNEL].SADDR =  (uint32_t)spip->txbuf;
       DMA->TCD[KINETIS_SPI0_TX_DMA_CHANNEL].SOFF = spip->word_size;
     } else {
-      DMA->TCD[KINETIS_SPI0_TX_DMA_CHANNEL].SADDR =  (uint32_t)&dmaDummy;
+      DMA->TCD[KINETIS_SPI0_TX_DMA_CHANNEL].SADDR =  (uint32_t)&dmaTxDummy;
       DMA->TCD[KINETIS_SPI0_TX_DMA_CHANNEL].SOFF = 0;
     }
     DMA->TCD[KINETIS_SPI0_TX_DMA_CHANNEL].BITER_ELINKNO = spip->count;