From fc81fc11182f56359a85c8f94aecfe5567d1329e Mon Sep 17 00:00:00 2001
From: George Hotz <george@comma.ai>
Date: Thu, 25 Jan 2018 23:51:52 -0800
Subject: [PATCH 01/13] uart dma in progress

---
 board/drivers/uart.h | 45 +++++++++++++++++++++++++++++++++++++++++++-
 board/main.c         | 11 ++++++++---
 2 files changed, 52 insertions(+), 4 deletions(-)

diff --git a/board/drivers/uart.h b/board/drivers/uart.h
index 2a21ffa23b8ef6..d79d74572fca8d 100644
--- a/board/drivers/uart.h
+++ b/board/drivers/uart.h
@@ -159,6 +159,36 @@ void uart_set_baud(USART_TypeDef *u, int baud) {
   }
 }
 
+#define USART1_DMA_LEN 0x40
+char usart1_dma[USART1_DMA_LEN];
+
+void DMA2_Stream5_IRQHandler(void) {
+  set_led(LED_BLUE, 1);
+
+  DMA2_Stream5->CR &= DMA_SxCR_EN;
+
+  uart_ring *q = &esp_ring;
+
+  int i;
+  for (i = 0; i < USART1_DMA_LEN; i++) {
+    char c = usart1_dma[i];
+    uint8_t next_w_ptr = q->w_ptr_rx + 1;
+    if (next_w_ptr != q->r_ptr_rx) {
+      q->elems_rx[q->w_ptr_rx] = c;
+      q->w_ptr_rx = next_w_ptr;
+      if (q->callback) q->callback(q);
+    }
+  }
+
+  DMA2_Stream5->M0AR = (uint32_t)usart1_dma;
+  DMA2_Stream5->NDTR = USART1_DMA_LEN;
+
+  DMA2_Stream5->CR = DMA_SxCR_CHSEL_2 | DMA_SxCR_MINC | DMA_SxCR_EN;
+  DMA2_Stream5->CR |= DMA_SxCR_TCIE;
+
+  DMA2->HIFCR = DMA_HIFCR_CTCIF5;
+}
+
 void uart_init(USART_TypeDef *u, int baud) {
   // enable uart and tx+rx mode
   u->CR1 = USART_CR1_UE;
@@ -173,7 +203,20 @@ void uart_init(USART_TypeDef *u, int baud) {
   u->CR1 |= USART_CR1_RXNEIE;
 
   if (u == USART1) {
-    NVIC_EnableIRQ(USART1_IRQn);
+    // DMA2, stream 2, channel 3
+    DMA2_Stream5->M0AR = (uint32_t)usart1_dma;
+    DMA2_Stream5->NDTR = USART1_DMA_LEN;
+    DMA2_Stream5->PAR = (uint32_t)&(USART1->DR);
+
+    // channel4, increment memory, periph -> memory, enable
+    DMA2_Stream5->CR = DMA_SxCR_CHSEL_2 | DMA_SxCR_MINC | DMA_SxCR_EN;
+    DMA2_Stream5->CR |= DMA_SxCR_TCIE;
+
+    // this one uses DMA receiver
+    u->CR3 = USART_CR3_DMAR;
+
+    NVIC_EnableIRQ(DMA2_Stream5_IRQn);
+    //NVIC_EnableIRQ(USART1_IRQn);
   } else if (u == USART2) {
     NVIC_EnableIRQ(USART2_IRQn);
   } else if (u == USART3) {
diff --git a/board/main.c b/board/main.c
index e50bcf8d27e8c6..de2cd4a04a2d0f 100644
--- a/board/main.c
+++ b/board/main.c
@@ -508,9 +508,12 @@ int main() {
   }
 
 #ifdef PANDA
-  // enable ESP uart
-  uart_init(USART1, 115200);
-
+  if (is_grey_panda) {
+    uart_init(USART1, 9600);
+  } else {
+    // enable ESP uart
+    uart_init(USART1, 115200);
+  }
   // enable LIN
   uart_init(UART5, 10400);
   UART5->CR2 |= USART_CR2_LINEN;
@@ -560,6 +563,8 @@ int main() {
   for (cnt=0;;cnt++) {
     can_live = pending_can_live;
 
+    puth(usart1_dma); puts(" "); puth(DMA2_Stream5->M0AR); puts(" "); puth(DMA2_Stream5->NDTR); puts("\n");
+
     #ifdef PANDA
       int current = adc_get(ADCCHAN_CURRENT);
 

From 743d244513f1bba8732bf202394cf3388520337d Mon Sep 17 00:00:00 2001
From: George Hotz <george@comma.ai>
Date: Sun, 28 Jan 2018 02:10:52 -0800
Subject: [PATCH 02/13] high baud rate works

---
 board/drivers/uart.h       | 38 +++++++++++++++++++++++++++-----------
 board/main.c               |  1 +
 tests/location_listener.py |  3 +--
 3 files changed, 29 insertions(+), 13 deletions(-)

diff --git a/board/drivers/uart.h b/board/drivers/uart.h
index d79d74572fca8d..5232d1d27fa8a4 100644
--- a/board/drivers/uart.h
+++ b/board/drivers/uart.h
@@ -162,31 +162,45 @@ void uart_set_baud(USART_TypeDef *u, int baud) {
 #define USART1_DMA_LEN 0x40
 char usart1_dma[USART1_DMA_LEN];
 
-void DMA2_Stream5_IRQHandler(void) {
-  set_led(LED_BLUE, 1);
+void uart_dma_drain() {
+  if (DMA2_Stream5->NDTR == USART1_DMA_LEN) return;
 
-  DMA2_Stream5->CR &= DMA_SxCR_EN;
+  enter_critical_section();
 
   uart_ring *q = &esp_ring;
 
+  // disable DMA
+  q->uart->CR3 &= ~USART_CR3_DMAR;
+  DMA2_Stream5->CR &= ~DMA_SxCR_EN;
+
+  //puth(DMA2_Stream5->NDTR); puts("\n");
+
   int i;
-  for (i = 0; i < USART1_DMA_LEN; i++) {
+  for (i = 0; i < USART1_DMA_LEN - DMA2_Stream5->NDTR; i++) {
     char c = usart1_dma[i];
     uint8_t next_w_ptr = q->w_ptr_rx + 1;
     if (next_w_ptr != q->r_ptr_rx) {
       q->elems_rx[q->w_ptr_rx] = c;
       q->w_ptr_rx = next_w_ptr;
-      if (q->callback) q->callback(q);
     }
   }
 
   DMA2_Stream5->M0AR = (uint32_t)usart1_dma;
   DMA2_Stream5->NDTR = USART1_DMA_LEN;
 
-  DMA2_Stream5->CR = DMA_SxCR_CHSEL_2 | DMA_SxCR_MINC | DMA_SxCR_EN;
-  DMA2_Stream5->CR |= DMA_SxCR_TCIE;
+  // clear interrupts
+  DMA2->HIFCR = DMA_HIFCR_CTCIF5 | DMA_HIFCR_CHTIF5;
+
+  // enable DMA
+  DMA2_Stream5->CR |= DMA_SxCR_EN;
+  q->uart->CR3 |= USART_CR3_DMAR;
 
-  DMA2->HIFCR = DMA_HIFCR_CTCIF5;
+  exit_critical_section();
+}
+
+void DMA2_Stream5_IRQHandler(void) {
+  //set_led(LED_BLUE, 1);
+  uart_dma_drain();
 }
 
 void uart_init(USART_TypeDef *u, int baud) {
@@ -200,7 +214,9 @@ void uart_init(USART_TypeDef *u, int baud) {
   // ** UART is ready to work **
 
   // enable interrupts
-  u->CR1 |= USART_CR1_RXNEIE;
+  if (u != USART1) {
+    u->CR1 |= USART_CR1_RXNEIE;
+  }
 
   if (u == USART1) {
     // DMA2, stream 2, channel 3
@@ -210,13 +226,13 @@ void uart_init(USART_TypeDef *u, int baud) {
 
     // channel4, increment memory, periph -> memory, enable
     DMA2_Stream5->CR = DMA_SxCR_CHSEL_2 | DMA_SxCR_MINC | DMA_SxCR_EN;
-    DMA2_Stream5->CR |= DMA_SxCR_TCIE;
+    DMA2_Stream5->CR |= DMA_SxCR_TCIE | DMA_SxCR_HTIE;
 
     // this one uses DMA receiver
     u->CR3 = USART_CR3_DMAR;
 
     NVIC_EnableIRQ(DMA2_Stream5_IRQn);
-    //NVIC_EnableIRQ(USART1_IRQn);
+    NVIC_EnableIRQ(USART1_IRQn);
   } else if (u == USART2) {
     NVIC_EnableIRQ(USART2_IRQn);
   } else if (u == USART3) {
diff --git a/board/main.c b/board/main.c
index de2cd4a04a2d0f..0a34458d7432e2 100644
--- a/board/main.c
+++ b/board/main.c
@@ -311,6 +311,7 @@ int usb_cb_control_msg(USB_Setup_TypeDef *setup, uint8_t *resp, int hardwired) {
     case 0xe0:
       ur = get_ring_by_number(setup->b.wValue.w);
       if (!ur) break;
+      if (ur == &esp_ring) uart_dma_drain();
       // read
       while ((resp_len < min(setup->b.wLength.w, MAX_RESP_LEN)) &&
                          getc(ur, (char*)&resp[resp_len])) {
diff --git a/tests/location_listener.py b/tests/location_listener.py
index 1f7fdb87fb691f..cbbb00d794f5e3 100755
--- a/tests/location_listener.py
+++ b/tests/location_listener.py
@@ -27,8 +27,7 @@ def add_nmea_checksum(msg):
   print ser.read(1024)
 
   # upping baud rate
-  # 460800 has issues
-  baudrate = 115200
+  baudrate = 460800
 
   print "upping baud rate"
   msg = add_nmea_checksum("$PUBX,41,1,0007,0003,%d,0" % baudrate)+"\r\n"

From 7c34afe53323b5178e941deef997eafd34cddbf8 Mon Sep 17 00:00:00 2001
From: George Hotz <george@comma.ai>
Date: Sun, 28 Jan 2018 03:18:07 -0800
Subject: [PATCH 03/13] minor change

---
 board/drivers/uart.h | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/board/drivers/uart.h b/board/drivers/uart.h
index 5232d1d27fa8a4..9da3ea493a07c0 100644
--- a/board/drivers/uart.h
+++ b/board/drivers/uart.h
@@ -163,29 +163,31 @@ void uart_set_baud(USART_TypeDef *u, int baud) {
 char usart1_dma[USART1_DMA_LEN];
 
 void uart_dma_drain() {
-  if (DMA2_Stream5->NDTR == USART1_DMA_LEN) return;
-
-  enter_critical_section();
-
   uart_ring *q = &esp_ring;
 
   // disable DMA
   q->uart->CR3 &= ~USART_CR3_DMAR;
   DMA2_Stream5->CR &= ~DMA_SxCR_EN;
 
-  //puth(DMA2_Stream5->NDTR); puts("\n");
+  if (DMA2_Stream5->NDTR != USART1_DMA_LEN) {
+    enter_critical_section();
 
-  int i;
-  for (i = 0; i < USART1_DMA_LEN - DMA2_Stream5->NDTR; i++) {
-    char c = usart1_dma[i];
-    uint8_t next_w_ptr = q->w_ptr_rx + 1;
-    if (next_w_ptr != q->r_ptr_rx) {
-      q->elems_rx[q->w_ptr_rx] = c;
-      q->w_ptr_rx = next_w_ptr;
+    //puth(DMA2_Stream5->NDTR); puts("\n");
+
+    int i;
+    for (i = 0; i < USART1_DMA_LEN - DMA2_Stream5->NDTR; i++) {
+      char c = usart1_dma[i];
+      uint8_t next_w_ptr = q->w_ptr_rx + 1;
+      if (next_w_ptr != q->r_ptr_rx) {
+        q->elems_rx[q->w_ptr_rx] = c;
+        q->w_ptr_rx = next_w_ptr;
+      }
     }
+
+    exit_critical_section();
   }
 
-  DMA2_Stream5->M0AR = (uint32_t)usart1_dma;
+  // reset DMA len
   DMA2_Stream5->NDTR = USART1_DMA_LEN;
 
   // clear interrupts
@@ -194,8 +196,6 @@ void uart_dma_drain() {
   // enable DMA
   DMA2_Stream5->CR |= DMA_SxCR_EN;
   q->uart->CR3 |= USART_CR3_DMAR;
-
-  exit_critical_section();
 }
 
 void DMA2_Stream5_IRQHandler(void) {

From 497f069e49e3cded5ad959ab8548276e06df42b1 Mon Sep 17 00:00:00 2001
From: George Hotz <george@comma.ai>
Date: Sun, 28 Jan 2018 03:20:19 -0800
Subject: [PATCH 04/13] dma is all critical, no interrupts

---
 board/drivers/uart.h | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/board/drivers/uart.h b/board/drivers/uart.h
index 9da3ea493a07c0..7d71c872690fd0 100644
--- a/board/drivers/uart.h
+++ b/board/drivers/uart.h
@@ -165,26 +165,20 @@ char usart1_dma[USART1_DMA_LEN];
 void uart_dma_drain() {
   uart_ring *q = &esp_ring;
 
+  enter_critical_section();
+
   // disable DMA
   q->uart->CR3 &= ~USART_CR3_DMAR;
   DMA2_Stream5->CR &= ~DMA_SxCR_EN;
 
-  if (DMA2_Stream5->NDTR != USART1_DMA_LEN) {
-    enter_critical_section();
-
-    //puth(DMA2_Stream5->NDTR); puts("\n");
-
-    int i;
-    for (i = 0; i < USART1_DMA_LEN - DMA2_Stream5->NDTR; i++) {
-      char c = usart1_dma[i];
-      uint8_t next_w_ptr = q->w_ptr_rx + 1;
-      if (next_w_ptr != q->r_ptr_rx) {
-        q->elems_rx[q->w_ptr_rx] = c;
-        q->w_ptr_rx = next_w_ptr;
-      }
+  int i;
+  for (i = 0; i < USART1_DMA_LEN - DMA2_Stream5->NDTR; i++) {
+    char c = usart1_dma[i];
+    uint8_t next_w_ptr = q->w_ptr_rx + 1;
+    if (next_w_ptr != q->r_ptr_rx) {
+      q->elems_rx[q->w_ptr_rx] = c;
+      q->w_ptr_rx = next_w_ptr;
     }
-
-    exit_critical_section();
   }
 
   // reset DMA len
@@ -196,6 +190,8 @@ void uart_dma_drain() {
   // enable DMA
   DMA2_Stream5->CR |= DMA_SxCR_EN;
   q->uart->CR3 |= USART_CR3_DMAR;
+
+  exit_critical_section();
 }
 
 void DMA2_Stream5_IRQHandler(void) {

From 37c52630a0296abb139d39e2f420a10f97be9703 Mon Sep 17 00:00:00 2001
From: George Hotz <george@comma.ai>
Date: Sun, 28 Jan 2018 03:54:47 -0800
Subject: [PATCH 05/13] big fifo

---
 board/drivers/drivers.h | 10 +++++-----
 board/drivers/uart.h    | 16 ++++++++--------
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/board/drivers/drivers.h b/board/drivers/drivers.h
index 871ee8fcf1f88a..ce1e860ceb8a80 100644
--- a/board/drivers/drivers.h
+++ b/board/drivers/drivers.h
@@ -57,13 +57,13 @@ void usb_cb_enumeration_complete();
 // ********************* UART *********************
 // IRQs: USART1, USART2, USART3, UART5
 
-#define FIFO_SIZE 0x100
+#define FIFO_SIZE 0x400
 typedef struct uart_ring {
-  uint8_t w_ptr_tx;
-  uint8_t r_ptr_tx;
+  uint16_t w_ptr_tx;
+  uint16_t r_ptr_tx;
   uint8_t elems_tx[FIFO_SIZE];
-  uint8_t w_ptr_rx;
-  uint8_t r_ptr_rx;
+  uint16_t w_ptr_rx;
+  uint16_t r_ptr_rx;
   uint8_t elems_rx[FIFO_SIZE];
   USART_TypeDef *uart;
   void (*callback)(struct uart_ring*);
diff --git a/board/drivers/uart.h b/board/drivers/uart.h
index 7d71c872690fd0..8fa195e01d39dd 100644
--- a/board/drivers/uart.h
+++ b/board/drivers/uart.h
@@ -52,7 +52,7 @@ void uart_ring_process(uart_ring *q) {
   if (q->w_ptr_tx != q->r_ptr_tx) {
     if (sr & USART_SR_TXE) {
       q->uart->DR = q->elems_tx[q->r_ptr_tx];
-      q->r_ptr_tx += 1;
+      q->r_ptr_tx = (q->r_ptr_tx + 1) % FIFO_SIZE;
     } else {
       // push on interrupt later
       q->uart->CR1 |= USART_CR1_TXEIE;
@@ -64,7 +64,7 @@ void uart_ring_process(uart_ring *q) {
 
   if (sr & USART_SR_RXNE || sr & USART_SR_ORE) {
     uint8_t c = q->uart->DR;  // TODO: can drop packets
-    uint8_t next_w_ptr = q->w_ptr_rx + 1;
+    uint16_t next_w_ptr = (q->w_ptr_rx + 1) % FIFO_SIZE;
     if (next_w_ptr != q->r_ptr_rx) {
       q->elems_rx[q->w_ptr_rx] = c;
       q->w_ptr_rx = next_w_ptr;
@@ -92,7 +92,7 @@ int getc(uart_ring *q, char *elem) {
   enter_critical_section();
   if (q->w_ptr_rx != q->r_ptr_rx) {
     *elem = q->elems_rx[q->r_ptr_rx];
-    q->r_ptr_rx += 1;
+    q->r_ptr_rx = (q->r_ptr_rx + 1) % FIFO_SIZE;
     ret = 1;
   }
   exit_critical_section();
@@ -102,10 +102,10 @@ int getc(uart_ring *q, char *elem) {
 
 int injectc(uart_ring *q, char elem) {
   int ret = 0;
-  uint8_t next_w_ptr;
+  uint16_t next_w_ptr;
 
   enter_critical_section();
-  next_w_ptr = q->w_ptr_rx + 1;
+  next_w_ptr = (q->w_ptr_rx + 1) % FIFO_SIZE;
   if (next_w_ptr != q->r_ptr_rx) {
     q->elems_rx[q->w_ptr_rx] = elem;
     q->w_ptr_rx = next_w_ptr;
@@ -118,10 +118,10 @@ int injectc(uart_ring *q, char elem) {
 
 int putc(uart_ring *q, char elem) {
   int ret = 0;
-  uint8_t next_w_ptr;
+  uint16_t next_w_ptr;
 
   enter_critical_section();
-  next_w_ptr = q->w_ptr_tx + 1;
+  next_w_ptr = (q->w_ptr_tx + 1) % FIFO_SIZE;
   if (next_w_ptr != q->r_ptr_tx) {
     q->elems_tx[q->w_ptr_tx] = elem;
     q->w_ptr_tx = next_w_ptr;
@@ -174,7 +174,7 @@ void uart_dma_drain() {
   int i;
   for (i = 0; i < USART1_DMA_LEN - DMA2_Stream5->NDTR; i++) {
     char c = usart1_dma[i];
-    uint8_t next_w_ptr = q->w_ptr_rx + 1;
+    uint16_t next_w_ptr = (q->w_ptr_rx + 1) % FIFO_SIZE;
     if (next_w_ptr != q->r_ptr_rx) {
       q->elems_rx[q->w_ptr_rx] = c;
       q->w_ptr_rx = next_w_ptr;

From fd053760d9792837b0a29add4212c0b35f558bdf Mon Sep 17 00:00:00 2001
From: George Hotz <george@comma.ai>
Date: Sun, 28 Jan 2018 03:58:57 -0800
Subject: [PATCH 06/13] comment out debug

---
 board/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/board/main.c b/board/main.c
index 0a34458d7432e2..5d239bdc6211ea 100644
--- a/board/main.c
+++ b/board/main.c
@@ -564,7 +564,7 @@ int main() {
   for (cnt=0;;cnt++) {
     can_live = pending_can_live;
 
-    puth(usart1_dma); puts(" "); puth(DMA2_Stream5->M0AR); puts(" "); puth(DMA2_Stream5->NDTR); puts("\n");
+    //puth(usart1_dma); puts(" "); puth(DMA2_Stream5->M0AR); puts(" "); puth(DMA2_Stream5->NDTR); puts("\n");
 
     #ifdef PANDA
       int current = adc_get(ADCCHAN_CURRENT);

From 915cd84f3382bd68d9fa122c208184b431d5813b Mon Sep 17 00:00:00 2001
From: George Hotz <george@comma.ai>
Date: Sun, 28 Jan 2018 04:32:06 -0800
Subject: [PATCH 07/13] ugh, ok, need that

---
 board/drivers/uart.h | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/board/drivers/uart.h b/board/drivers/uart.h
index 8fa195e01d39dd..e749c6b8bed2a1 100644
--- a/board/drivers/uart.h
+++ b/board/drivers/uart.h
@@ -64,11 +64,13 @@ void uart_ring_process(uart_ring *q) {
 
   if (sr & USART_SR_RXNE || sr & USART_SR_ORE) {
     uint8_t c = q->uart->DR;  // TODO: can drop packets
-    uint16_t next_w_ptr = (q->w_ptr_rx + 1) % FIFO_SIZE;
-    if (next_w_ptr != q->r_ptr_rx) {
-      q->elems_rx[q->w_ptr_rx] = c;
-      q->w_ptr_rx = next_w_ptr;
-      if (q->callback) q->callback(q);
+    if (q != &esp_ring) {
+      uint16_t next_w_ptr = (q->w_ptr_rx + 1) % FIFO_SIZE;
+      if (next_w_ptr != q->r_ptr_rx) {
+        q->elems_rx[q->w_ptr_rx] = c;
+        q->w_ptr_rx = next_w_ptr;
+        if (q->callback) q->callback(q);
+      }
     }
   }
 

From 1465aa478f101b2aab148d95877ff793a8717bf2 Mon Sep 17 00:00:00 2001
From: George Hotz <george@comma.ai>
Date: Sun, 28 Jan 2018 04:56:33 -0800
Subject: [PATCH 08/13] ok, it's fixed

---
 board/drivers/uart.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/board/drivers/uart.h b/board/drivers/uart.h
index e749c6b8bed2a1..e1b98090e04cc6 100644
--- a/board/drivers/uart.h
+++ b/board/drivers/uart.h
@@ -172,6 +172,7 @@ void uart_dma_drain() {
   // disable DMA
   q->uart->CR3 &= ~USART_CR3_DMAR;
   DMA2_Stream5->CR &= ~DMA_SxCR_EN;
+  while (DMA2_Stream5->CR & DMA_SxCR_EN);
 
   int i;
   for (i = 0; i < USART1_DMA_LEN - DMA2_Stream5->NDTR; i++) {
@@ -188,6 +189,7 @@ void uart_dma_drain() {
 
   // clear interrupts
   DMA2->HIFCR = DMA_HIFCR_CTCIF5 | DMA_HIFCR_CHTIF5;
+  //DMA2->HIFCR = DMA_HIFCR_CTEIF5 | DMA_HIFCR_CDMEIF5 | DMA_HIFCR_CFEIF5;
 
   // enable DMA
   DMA2_Stream5->CR |= DMA_SxCR_EN;
@@ -199,6 +201,7 @@ void uart_dma_drain() {
 void DMA2_Stream5_IRQHandler(void) {
   //set_led(LED_BLUE, 1);
   uart_dma_drain();
+  //set_led(LED_BLUE, 0);
 }
 
 void uart_init(USART_TypeDef *u, int baud) {
@@ -224,7 +227,7 @@ void uart_init(USART_TypeDef *u, int baud) {
 
     // channel4, increment memory, periph -> memory, enable
     DMA2_Stream5->CR = DMA_SxCR_CHSEL_2 | DMA_SxCR_MINC | DMA_SxCR_EN;
-    DMA2_Stream5->CR |= DMA_SxCR_TCIE | DMA_SxCR_HTIE;
+    DMA2_Stream5->CR |= DMA_SxCR_HTIE;
 
     // this one uses DMA receiver
     u->CR3 = USART_CR3_DMAR;

From 7fa4808cf8595f43ef8dca6edcf7cef1a4bc318a Mon Sep 17 00:00:00 2001
From: George Hotz <george@comma.ai>
Date: Sun, 28 Jan 2018 11:20:28 -0800
Subject: [PATCH 09/13] froze up, maybe thats the fix

---
 board/drivers/uart.h | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/board/drivers/uart.h b/board/drivers/uart.h
index e1b98090e04cc6..c664894694848e 100644
--- a/board/drivers/uart.h
+++ b/board/drivers/uart.h
@@ -170,7 +170,7 @@ void uart_dma_drain() {
   enter_critical_section();
 
   // disable DMA
-  q->uart->CR3 &= ~USART_CR3_DMAR;
+  //q->uart->CR3 &= ~USART_CR3_DMAR;
   DMA2_Stream5->CR &= ~DMA_SxCR_EN;
   while (DMA2_Stream5->CR & DMA_SxCR_EN);
 
@@ -193,7 +193,7 @@ void uart_dma_drain() {
 
   // enable DMA
   DMA2_Stream5->CR |= DMA_SxCR_EN;
-  q->uart->CR3 |= USART_CR3_DMAR;
+  //q->uart->CR3 |= USART_CR3_DMAR;
 
   exit_critical_section();
 }
@@ -226,8 +226,7 @@ void uart_init(USART_TypeDef *u, int baud) {
     DMA2_Stream5->PAR = (uint32_t)&(USART1->DR);
 
     // channel4, increment memory, periph -> memory, enable
-    DMA2_Stream5->CR = DMA_SxCR_CHSEL_2 | DMA_SxCR_MINC | DMA_SxCR_EN;
-    DMA2_Stream5->CR |= DMA_SxCR_HTIE;
+    DMA2_Stream5->CR = DMA_SxCR_CHSEL_2 | DMA_SxCR_MINC | DMA_SxCR_HTIE | DMA_SxCR_EN;
 
     // this one uses DMA receiver
     u->CR3 = USART_CR3_DMAR;

From 8b7e8495db25199f255eb74452537125f0f77628 Mon Sep 17 00:00:00 2001
From: George Hotz <george@comma.ai>
Date: Mon, 29 Jan 2018 00:59:48 -0800
Subject: [PATCH 10/13] working now

---
 board/drivers/uart.h | 46 +++++++++++++++++++++++---------------------
 1 file changed, 24 insertions(+), 22 deletions(-)

diff --git a/board/drivers/uart.h b/board/drivers/uart.h
index c664894694848e..a8e64b887fd33e 100644
--- a/board/drivers/uart.h
+++ b/board/drivers/uart.h
@@ -169,31 +169,33 @@ void uart_dma_drain() {
 
   enter_critical_section();
 
-  // disable DMA
-  //q->uart->CR3 &= ~USART_CR3_DMAR;
-  DMA2_Stream5->CR &= ~DMA_SxCR_EN;
-  while (DMA2_Stream5->CR & DMA_SxCR_EN);
-
-  int i;
-  for (i = 0; i < USART1_DMA_LEN - DMA2_Stream5->NDTR; i++) {
-    char c = usart1_dma[i];
-    uint16_t next_w_ptr = (q->w_ptr_rx + 1) % FIFO_SIZE;
-    if (next_w_ptr != q->r_ptr_rx) {
-      q->elems_rx[q->w_ptr_rx] = c;
-      q->w_ptr_rx = next_w_ptr;
+  if (DMA2_Stream5->NDTR != USART1_DMA_LEN) {
+    // disable DMA
+    //q->uart->CR3 &= ~USART_CR3_DMAR;
+    DMA2_Stream5->CR &= ~DMA_SxCR_EN;
+    while (DMA2_Stream5->CR & DMA_SxCR_EN);
+
+    int i;
+    for (i = 0; i < USART1_DMA_LEN - DMA2_Stream5->NDTR; i++) {
+      char c = usart1_dma[i];
+      uint16_t next_w_ptr = (q->w_ptr_rx + 1) % FIFO_SIZE;
+      if (next_w_ptr != q->r_ptr_rx) {
+        q->elems_rx[q->w_ptr_rx] = c;
+        q->w_ptr_rx = next_w_ptr;
+      }
     }
-  }
 
-  // reset DMA len
-  DMA2_Stream5->NDTR = USART1_DMA_LEN;
+    // reset DMA len
+    DMA2_Stream5->NDTR = USART1_DMA_LEN;
 
-  // clear interrupts
-  DMA2->HIFCR = DMA_HIFCR_CTCIF5 | DMA_HIFCR_CHTIF5;
-  //DMA2->HIFCR = DMA_HIFCR_CTEIF5 | DMA_HIFCR_CDMEIF5 | DMA_HIFCR_CFEIF5;
+    // clear interrupts
+    DMA2->HIFCR = DMA_HIFCR_CTCIF5 | DMA_HIFCR_CHTIF5;
+    //DMA2->HIFCR = DMA_HIFCR_CTEIF5 | DMA_HIFCR_CDMEIF5 | DMA_HIFCR_CFEIF5;
 
-  // enable DMA
-  DMA2_Stream5->CR |= DMA_SxCR_EN;
-  //q->uart->CR3 |= USART_CR3_DMAR;
+    // enable DMA
+    DMA2_Stream5->CR |= DMA_SxCR_EN;
+    //q->uart->CR3 |= USART_CR3_DMAR;
+  }
 
   exit_critical_section();
 }
@@ -226,7 +228,7 @@ void uart_init(USART_TypeDef *u, int baud) {
     DMA2_Stream5->PAR = (uint32_t)&(USART1->DR);
 
     // channel4, increment memory, periph -> memory, enable
-    DMA2_Stream5->CR = DMA_SxCR_CHSEL_2 | DMA_SxCR_MINC | DMA_SxCR_HTIE | DMA_SxCR_EN;
+    DMA2_Stream5->CR = DMA_SxCR_CHSEL_2 | DMA_SxCR_MINC | DMA_SxCR_HTIE | DMA_SxCR_TCIE | DMA_SxCR_EN;
 
     // this one uses DMA receiver
     u->CR3 = USART_CR3_DMAR;

From a9f6bf05956c66c6bfb55002e8bf4771137e3174 Mon Sep 17 00:00:00 2001
From: George Hotz <george@comma.ai>
Date: Mon, 29 Jan 2018 01:32:37 -0800
Subject: [PATCH 11/13] this

---
 board/drivers/uart.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/board/drivers/uart.h b/board/drivers/uart.h
index a8e64b887fd33e..d8ce18a4e40b11 100644
--- a/board/drivers/uart.h
+++ b/board/drivers/uart.h
@@ -169,7 +169,7 @@ void uart_dma_drain() {
 
   enter_critical_section();
 
-  if (DMA2_Stream5->NDTR != USART1_DMA_LEN) {
+  if (DMA2->HISR & DMA_HISR_TCIF5 || DMA2->HISR & DMA_HISR_HTIF5 || DMA2_Stream5->NDTR != USART1_DMA_LEN) {
     // disable DMA
     //q->uart->CR3 &= ~USART_CR3_DMAR;
     DMA2_Stream5->CR &= ~DMA_SxCR_EN;

From be99ffca784030454227870976ee43281393c2ca Mon Sep 17 00:00:00 2001
From: George Hotz <george@comma.ai>
Date: Mon, 29 Jan 2018 01:42:56 -0800
Subject: [PATCH 12/13] ok that doesn't hurt i think

---
 board/drivers/uart.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/board/drivers/uart.h b/board/drivers/uart.h
index d8ce18a4e40b11..75a53989fd545b 100644
--- a/board/drivers/uart.h
+++ b/board/drivers/uart.h
@@ -171,7 +171,7 @@ void uart_dma_drain() {
 
   if (DMA2->HISR & DMA_HISR_TCIF5 || DMA2->HISR & DMA_HISR_HTIF5 || DMA2_Stream5->NDTR != USART1_DMA_LEN) {
     // disable DMA
-    //q->uart->CR3 &= ~USART_CR3_DMAR;
+    q->uart->CR3 &= ~USART_CR3_DMAR;
     DMA2_Stream5->CR &= ~DMA_SxCR_EN;
     while (DMA2_Stream5->CR & DMA_SxCR_EN);
 
@@ -194,7 +194,7 @@ void uart_dma_drain() {
 
     // enable DMA
     DMA2_Stream5->CR |= DMA_SxCR_EN;
-    //q->uart->CR3 |= USART_CR3_DMAR;
+    q->uart->CR3 |= USART_CR3_DMAR;
   }
 
   exit_critical_section();

From fd68f86cad8051fd00298846e8c506ccbeb399e8 Mon Sep 17 00:00:00 2001
From: George Hotz <george@comma.ai>
Date: Mon, 29 Jan 2018 02:03:46 -0800
Subject: [PATCH 13/13] smallr

---
 board/drivers/uart.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/board/drivers/uart.h b/board/drivers/uart.h
index 75a53989fd545b..9c01416920d230 100644
--- a/board/drivers/uart.h
+++ b/board/drivers/uart.h
@@ -161,7 +161,7 @@ void uart_set_baud(USART_TypeDef *u, int baud) {
   }
 }
 
-#define USART1_DMA_LEN 0x40
+#define USART1_DMA_LEN 0x20
 char usart1_dma[USART1_DMA_LEN];
 
 void uart_dma_drain() {