From e6401d2e83939a63cbd156fa193f9768063d9325 Mon Sep 17 00:00:00 2001
From: Randall Spangler <rspangler@chromium.org>
Date: Fri, 6 Sep 2013 15:56:48 -0700
Subject: Initalize DMA before UART

This is in preparation for enabling DMA-based UART transfers, to
improve UART performance on STM32.

BUG=chrome-os-partner:20485
BRANCH=none
TEST=Boot pit.  Host commands should still be received; this verifies DMA
     is still operational.

Change-Id: Ibc3b2e2cd187547eb61b85e4a086704accd7f2fb
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/168810
---
 chip/stm32/config_chip.h |  3 +++
 chip/stm32/dma.c         |  3 +--
 common/main.c            |  6 ++++++
 include/config.h         |  3 +++
 include/dma.h            | 10 +++++++++-
 5 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/chip/stm32/config_chip.h b/chip/stm32/config_chip.h
index 40de499fd5..fa839287e0 100644
--- a/chip/stm32/config_chip.h
+++ b/chip/stm32/config_chip.h
@@ -47,6 +47,9 @@
  */
 #define CONFIG_WATCHDOG_HELP
 
+/* Use DMA */
+#define CONFIG_DMA
+
 /* Flash protection applies to the next boot, not the current one */
 #define CONFIG_FLASH_PROTECT_NEXT_BOOT
 
diff --git a/chip/stm32/dma.c b/chip/stm32/dma.c
index c4eb08d4ec..06da15e1b6 100644
--- a/chip/stm32/dma.c
+++ b/chip/stm32/dma.c
@@ -182,7 +182,7 @@ void dma_test(void)
 }
 #endif /* CONFIG_DMA_HELP */
 
-static void dma_init(void)
+void dma_init(void)
 {
 	int i;
 
@@ -193,7 +193,6 @@ static void dma_init(void)
 	for (i = 0; i < STM32_DMAC_COUNT; i++)
 		id[i] = TASK_ID_INVALID;
 }
-DECLARE_HOOK(HOOK_INIT, dma_init, HOOK_PRIO_INIT_DMA);
 
 int dma_wait(enum dma_channel channel)
 {
diff --git a/common/main.c b/common/main.c
index ec4bc2b48c..12d9f9ec5b 100644
--- a/common/main.c
+++ b/common/main.c
@@ -10,6 +10,7 @@
 #include "common.h"
 #include "console.h"
 #include "cpu.h"
+#include "dma.h"
 #include "eeprom.h"
 #include "eoption.h"
 #include "flash.h"
@@ -90,6 +91,11 @@ test_mockable int main(void)
 	/* Main initialization stage.  Modules may enable interrupts here. */
 	cpu_init();
 
+#ifdef CONFIG_DMA
+	/* Initialize DMA.  Must be before UART. */
+	dma_init();
+#endif
+
 	/* Initialize UART.  Console output functions may now be used. */
 	uart_init();
 
diff --git a/include/config.h b/include/config.h
index d46ae943f2..8b5e2a9214 100644
--- a/include/config.h
+++ b/include/config.h
@@ -280,6 +280,9 @@
 
 /*****************************************************************************/
 
+/* Compile support for the DMA module */
+#undef CONFIG_DMA
+
 /* Compile extra debugging and tests for the DMA module */
 #undef CONFIG_DMA_HELP
 
diff --git a/include/dma.h b/include/dma.h
index 1b03795b36..04c1be2bf9 100644
--- a/include/dma.h
+++ b/include/dma.h
@@ -2,12 +2,14 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  *
- * Register map and API for STM32 processor dma registers
+ * DMA interface
  */
 
 #ifndef __CROS_EC_DMA_H
 #define __CROS_EC_DMA_H
 
+#ifdef CONFIG_DMA
+
 #include "common.h"
 #include "registers.h"
 
@@ -134,4 +136,10 @@ void dma_disable_tc_interrupt(enum dma_channel channel);
  */
 int dma_wait(enum dma_channel channel);
 
+/**
+ * Initialize the DMA module.
+ */
+void dma_init(void);
+
+#endif /* CONFIG_DMA */
 #endif
-- 
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