From ff3329655a2f2b1d3d89a06f941da420845908bb Mon Sep 17 00:00:00 2001
From: Matthew Kennedy <matthewkennedy@outlook.com>
Date: Tue, 28 Jan 2020 21:32:43 -0800
Subject: [PATCH] Dont cache dma buffers (#1110)

* add no_cache

* don't disable cache

* conventions

* formatting
---
 firmware/global.h                               |  2 ++
 firmware/hw_layer/mmc_card.cpp                  |  4 ++--
 .../hw_layer/ports/stm32/stm32f7/mpu_util.cpp   |  5 +----
 firmware/hw_layer/sensors/cj125.cpp             | 17 +++++------------
 4 files changed, 10 insertions(+), 18 deletions(-)

diff --git a/firmware/global.h b/firmware/global.h
index 732c9c02ae..1cb7054642 100644
--- a/firmware/global.h
+++ b/firmware/global.h
@@ -77,8 +77,10 @@ typedef unsigned int time_t;
  */
 #if defined(STM32F7XX)
 #define CCM_RAM ".ram3"
+#define NO_CACHE CCM_OPTIONAL
 #else /* defined(STM32F4XX) */
 #define CCM_RAM ".ram4"
+#define NO_CACHE
 #endif /* defined(STM32F4XX) */
 
 #if EFI_USE_CCM
diff --git a/firmware/hw_layer/mmc_card.cpp b/firmware/hw_layer/mmc_card.cpp
index deb3205021..776762d88a 100644
--- a/firmware/hw_layer/mmc_card.cpp
+++ b/firmware/hw_layer/mmc_card.cpp
@@ -121,8 +121,8 @@ static void printError(const char *str, FRESULT f_error) {
 	scheduleMsg(&logger, "FATfs Error \"%s\" %d", str, f_error);
 }
 
-static FIL FDLogFile;
-static FIL FDCurrFile;
+static FIL FDLogFile NO_CACHE;
+static FIL FDCurrFile NO_CACHE;
 static int logFileIndex = 1;
 static char logName[_MAX_FILLER + 20];
 
diff --git a/firmware/hw_layer/ports/stm32/stm32f7/mpu_util.cpp b/firmware/hw_layer/ports/stm32/stm32f7/mpu_util.cpp
index 3de85cf0a7..647181b6e1 100644
--- a/firmware/hw_layer/ports/stm32/stm32f7/mpu_util.cpp
+++ b/firmware/hw_layer/ports/stm32/stm32f7/mpu_util.cpp
@@ -77,12 +77,9 @@ EXTERNC int getRemainingStack(thread_t *otp) {
 
 void baseMCUInit(void) {
 	// looks like this holds a random value on start? Let's set a nice clean zero
-        DWT->CYCCNT = 0;
+	DWT->CYCCNT = 0;
 
 	BOR_Set(BOR_Level_1); // one step above default value
-
-// open question if we need this or not
-	//	SCB_DisableDCache();
 }
 
 void _unhandled_exception(void) {
diff --git a/firmware/hw_layer/sensors/cj125.cpp b/firmware/hw_layer/sensors/cj125.cpp
index 14bf2e2acb..78577c8d53 100644
--- a/firmware/hw_layer/sensors/cj125.cpp
+++ b/firmware/hw_layer/sensors/cj125.cpp
@@ -29,12 +29,9 @@ EXTERN_ENGINE;
 #include "pin_repository.h"
 
 static Logging *logger;
-/**
- * We need to make sure we do not get F7 SPI DMA caching issues
- * We also have "SCB_DisableDCache();" which is about the same since we need DMA SPI addressed not only for cj125
- */
-static unsigned char tx_buff[2] CCM_OPTIONAL;
-static unsigned char rx_buff[1] CCM_OPTIONAL;
+
+static uint8_t tx_buff[2] NO_CACHE;
+static uint8_t rx_buff[1] NO_CACHE;
 
 static CJ125 globalInstance;
 
@@ -83,15 +80,11 @@ static constexpr float lambdaLsu49[] = {
 };
 
 
-static int cjReadRegister(unsigned char regAddr) {
+static uint8_t cjReadRegister(uint8_t regAddr) {
 #if ! EFI_UNIT_TEST
 	spiSelect(driver);
 	tx_buff[0] = regAddr;
 	spiSend(driver, 1, tx_buff);
-	// safety?
-	chThdSleepMilliseconds(10);
-	
-	rx_buff[0] = 0;
 	spiReceive(driver, 1, rx_buff);
 	spiUnselect(driver);
 
@@ -104,7 +97,7 @@ static int cjReadRegister(unsigned char regAddr) {
 #endif /* EFI_UNIT_TEST */
 }
 
-static void cjWriteRegister(unsigned char regAddr, unsigned char regValue) {
+static void cjWriteRegister(uint8_t regAddr, uint8_t regValue) {
 	tx_buff[0] = regAddr;
 	tx_buff[1] = regValue;
 #ifdef CJ125_DEBUG_SPI