stm32: STM32F0 CAN feature

Signed-off-by: Eug Krashtan <eug.krashtan@gmail.com>
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

4 files changed, 290 insertions, 0 deletions

diff --git a/src/stm32/Kconfig b/src/stm32/Kconfig
index 6bfc15e2..c29ad205 100644
--- a/src/stm32/Kconfig
+++ b/src/stm32/Kconfig
@@ -135,9 +135,13 @@ config CANSERIAL
     bool "Use CAN for communication (instead of serial)"
     depends on MACH_STM32F042 && !USBSERIAL
     default n
+config SERIAL_BAUD
+    int "CAN bus speed" if LOW_LEVEL_OPTIONS && CANSERIAL
+    default 500000 if CANSERIAL
 config STM32F042_PIN_SWAP
     bool "Use PA9/PA10 for USB or CAN" if MACH_STM32F042
     depends on (USBSERIAL || CANSERIAL) && MACH_STM32F042
+    default y if (USBSERIAL || CANSERIAL)
     default n
 config SERIAL
     depends on !USBSERIAL && !CANSERIAL
diff --git a/src/stm32/Makefile b/src/stm32/Makefile
index 3a063402..e5627ec4 100644
--- a/src/stm32/Makefile
+++ b/src/stm32/Makefile
@@ -41,6 +41,8 @@ src-$(CONFIG_USBSERIAL) += $(usb-src-y) stm32/chipid.c generic/usb_cdc.c
 serial-src-y := stm32/serial.c
 serial-src-$(CONFIG_MACH_STM32F0) := stm32/stm32f0_serial.c
 src-$(CONFIG_SERIAL) += $(serial-src-y) generic/serial_irq.c
+can-src-$(CONFIG_MACH_STM32F0) := stm32/stm32f0_can.c
+src-$(CONFIG_CANSERIAL) += $(can-src-y) generic/serial_irq.c
 
 # Binary output file rules
 target-y += $(OUT)klipper.bin
diff --git a/src/stm32/stm32f0_can.c b/src/stm32/stm32f0_can.c
new file mode 100644
index 00000000..2523ba5f
--- /dev/null
+++ b/src/stm32/stm32f0_can.c
@@ -0,0 +1,267 @@
+/*
+ * Serial over CAN emulation for STM32F042 boards.
+ *
+ *  Copyright (C) 2019 Eug Krashtan <eug.krashtan@gmail.com>
+ *  This file may be distributed under the terms of the GNU GPLv3 license.
+ *
+ */
+
+#include "autoconf.h" // CONFIG_SERIAL_BAUD
+#include "board/armcm_boot.h" // armcm_enable_irq
+#include "board/serial_irq.h" // serial_rx_byte
+#include "command.h" // DECL_CONSTANT_STR
+#include "internal.h" // enable_pclock
+#include "sched.h" // DECL_INIT
+#include <string.h>
+#include "stm32f0_can.h"
+
+DECL_CONSTANT_STR("RESERVE_PINS_CAN", "PA11,PA12");
+#define GPIO_Rx GPIO('A', 11)
+#define GPIO_Tx GPIO('A', 12)
+#define MCR_FLAGS (CAN_MCR_NART)
+#define BTR_FLAGS (CAN_BTR_TS1_2 | CAN_BTR_TS2_0 | /* prescaler */ 11U )
+#define CAN_FILTER_NUMBER 0
+#define CAN_DATA3_Pos 24
+#define CAN_DATA2_Pos 16
+#define CAN_DATA1_Pos 8
+#define CAN_DATA0_Pos 0
+
+static uint16_t MyCanId = 0;
+
+static void can_transmit(uint32_t id, uint32_t dlc, uint8_t *pkt)
+{
+    /* ToDo: implement serial_get_tx_byte() inside TXComplete interrupt */
+
+    /* Use only Mailbox 0 to avoid message fragmentation */
+    while( !(CAN->TSR & CAN_TSR_TME0) ) /* wait until previous TX completes */
+        ;
+
+    /* Set up the Id */
+    CAN->sTxMailBox[0].TIR &= CAN_TI1R_TXRQ;
+    CAN->sTxMailBox[0].TIR |= (id << CAN_TI1R_STID_Pos);
+
+    /* Set up the DLC */
+    CAN->sTxMailBox[0].TDTR &= 0xFFFFFFF0U;
+    CAN->sTxMailBox[0].TDTR |= (dlc & 0xFU);
+
+    /* Set up the data field */
+    if(pkt) {
+        CAN->sTxMailBox[0].TDLR = ((uint32_t)pkt[3] << CAN_DATA3_Pos) |
+                        ((uint32_t)pkt[2] << CAN_DATA2_Pos) |
+                        ((uint32_t)pkt[1] << CAN_DATA1_Pos) |
+                        ((uint32_t)pkt[0] << CAN_DATA0_Pos);
+        CAN->sTxMailBox[0].TDHR = ((uint32_t)pkt[7] << CAN_DATA3_Pos) |
+                        ((uint32_t)pkt[6] << CAN_DATA2_Pos) |
+                        ((uint32_t)pkt[5] << CAN_DATA1_Pos) |
+                        ((uint32_t)pkt[4] << CAN_DATA0_Pos);
+    }
+
+     /* Request transmission */
+    __sync_synchronize(); // disable write optimization
+    CAN->sTxMailBox[0].TIR |= CAN_TI1R_TXRQ;
+}
+
+// Convert Unique 96-bit value into 48 bit representation
+static void pack_uuid(uint8_t* u)
+{
+    for(int i=0; i<SHORT_UUID_LEN; i++) {
+        u[i] = *((uint8_t*)(STM32_UUID_ADDR+i)) ^
+                *((uint8_t*)(STM32_UUID_ADDR+i+SHORT_UUID_LEN));
+    }
+}
+
+static void can_uuid_resp(void)
+{
+    uint8_t short_uuid[SHORT_UUID_LEN];
+    pack_uuid(short_uuid);
+    can_transmit(PKT_ID_UUID_RESP, SHORT_UUID_LEN, short_uuid);
+}
+
+static void get_data(uint8_t* buf, uint8_t mbox)
+{
+    for(int i=0; i < 8; i++ ) {
+        if (i<4) {
+            buf[i] = (CAN->sFIFOMailBox[mbox].RDLR >> (i*8)) & 0xFF;
+        } else {
+            buf[i] = (CAN->sFIFOMailBox[mbox].RDHR >> ((i-4)*8))& 0xFF;
+        }
+    }
+}
+
+void CAN_RxCpltCallback(uint8_t mbox)
+{
+    uint32_t id = (CAN->sFIFOMailBox[mbox].RIR >> CAN_RI0R_STID_Pos) & 0x7FF;
+    uint8_t dlc = CAN->sFIFOMailBox[mbox].RDTR & CAN_RDT0R_DLC;
+    uint8_t databuf[8];
+
+    if(!MyCanId) { // If serial not assigned yet
+        if(id==PKT_ID_UUID && dlc == 0) {
+            // Just inform host about my UUID
+            can_uuid_resp();
+        } else if (id == PKT_ID_SET) {
+            uint8_t short_uuid[SHORT_UUID_LEN];
+            pack_uuid(short_uuid);
+
+            // compare my UUID with packet to check if this packet mine
+            get_data(databuf, mbox);
+            if (memcmp(&(databuf[2]), short_uuid, SHORT_UUID_LEN) == 0) {
+                memcpy(&MyCanId, databuf, sizeof(uint16_t));
+                /* Set new filter values */
+                uint32_t filternbrbitpos = (1U) << CAN_FILTER_NUMBER;
+                CAN->FA1R &= ~(filternbrbitpos);
+                /* Personal ID */
+                CAN->sFilterRegister[CAN_FILTER_NUMBER].FR1 =
+                        ((uint32_t)(MyCanId<<5) << 16U);
+                /* Catch reset command */
+                CAN->sFilterRegister[CAN_FILTER_NUMBER].FR2 =
+                        ((uint32_t)(PKT_ID_UUID<<5) << 16U);
+                /* Filter activation */
+                CAN->FA1R |= filternbrbitpos;
+                /* Leave the initialisation mode for the filter */
+                CAN->FMR &= ~(CAN_FMR_FINIT);
+            }
+        }
+    }  else {
+        if (id == MyCanId) {
+            // compare my UUID with packet to check if this packet mine
+            if(dlc == 0) {
+                // empty packet == ping request
+                can_transmit(MyCanId+1, 0, NULL);
+            } else {
+                get_data(databuf, mbox);
+                for(int i=0; i < dlc; i++ ) {
+                    serial_rx_byte(databuf[i]);
+                }
+            }
+        }
+        else if (id == PKT_ID_UUID && dlc > 0)
+        {
+            get_data(databuf, mbox);
+            if (memcmp(databuf, &MyCanId, 2) == 0)
+            {
+                // Reset from host
+                NVIC_SystemReset();
+            }
+        }
+    }
+}
+
+/**
+  * @brief This function handles HDMI-CEC and CAN global interrupts /
+  *  HDMI-CEC wake-up interrupt through EXTI line 27.
+  */
+void
+CEC_CAN_IRQHandler(void)
+{
+    if (CAN->RF0R & CAN_RF0R_FMP0) {
+        // Mailbox 0
+        while(CAN->RF0R & CAN_RF0R_FMP0) {
+            CAN_RxCpltCallback(0);
+            CAN->RF0R |= CAN_RF0R_RFOM0;
+        }
+    }
+    if (CAN->RF1R & CAN_RF1R_FMP1) {
+        // Mailbox 1
+        while(CAN->RF1R & CAN_RF1R_FMP1) {
+            CAN_RxCpltCallback(1);
+            CAN->RF1R |= CAN_RF1R_RFOM1;
+        }
+    }
+
+    /* Check Overrun flag for FIFO0 */
+    if(CAN->RF0R & CAN_RF0R_FOVR0)
+    {
+        /* Clear FIFO0 Overrun Flag */
+        CAN->RF0R |= CAN_RF0R_FOVR0;
+    }
+    /* Check Overrun flag for FIFO1 */
+    if(CAN->RF1R & CAN_RF1R_FOVR1)
+    {
+        /* Clear FIFO1 Overrun Flag */
+        CAN->RF1R |= CAN_RF1R_FOVR1;
+    }
+}
+
+void
+can_init(void)
+{
+    enable_pclock((uint32_t)CAN);
+    gpio_peripheral(GPIO_Rx, GPIO_FUNCTION(4), 1);
+    gpio_peripheral(GPIO_Tx, GPIO_FUNCTION(4), 0);
+
+    /*##-1- Configure the CAN #######################################*/
+
+    /* Exit from sleep mode */
+    CAN->MCR &= ~(CAN_MCR_SLEEP);
+    /* Request initialisation */
+    CAN->MCR |= CAN_MCR_INRQ;
+    /* Wait the acknowledge */
+    while( !(CAN->MSR & CAN_MSR_INAK) );
+
+    CAN->MCR |= MCR_FLAGS;
+    CAN->BTR = BTR_FLAGS;
+
+    /* Request leave initialisation */
+    CAN->MCR &= ~(CAN_MCR_INRQ);
+    /* Wait the acknowledge */
+    while( CAN->MSR & CAN_MSR_INAK );
+
+    /*##-2- Configure the CAN Filter #######################################*/
+    uint32_t filternbrbitpos = (1U) << CAN_FILTER_NUMBER;
+
+    /* Select the start slave bank */
+    CAN->FMR |= CAN_FMR_FINIT;
+    /* Initialisation mode for the filter */
+    CAN->FA1R &= ~(filternbrbitpos);
+
+    CAN->sFilterRegister[CAN_FILTER_NUMBER].FR1 =
+            ((uint32_t)(PKT_ID_UUID<<5) << 16U);
+    CAN->sFilterRegister[CAN_FILTER_NUMBER].FR2 =
+            ((uint32_t)(PKT_ID_SET<<5) << 16U);
+
+    /*Identifier list mode for the filter*/
+    CAN->FM1R |= filternbrbitpos;
+    /* 32-bit scale for the filter */
+    CAN->FS1R |= filternbrbitpos;
+
+    /* FIFO 0 assignation for the filter */
+    CAN->FFA1R &= ~(filternbrbitpos);
+
+    /* Filter activation */
+    CAN->FA1R |= filternbrbitpos;
+    /* Leave the initialisation mode for the filter */
+    CAN->FMR &= ~(CAN_FMR_FINIT);
+
+    /*##-3- Configure Transmission process #################################*/
+
+    CAN->IER |= (CAN_IER_FMPIE0 | CAN_IER_FMPIE1);
+    armcm_enable_irq(CEC_CAN_IRQHandler, CEC_CAN_IRQn, 0);
+
+    /*##-4- Say Hello #################################*/
+    can_uuid_resp();
+}
+DECL_INIT(can_init);
+
+void
+serial_enable_tx_irq(void)
+{
+    uint8_t databuf[8];
+    if(MyCanId == 0)
+        // Serial port not initialized
+        return;
+    uint8_t txdata =1;
+    while(txdata) {
+        int i=0;
+        for (;i<8;)
+        {
+            if(serial_get_tx_byte(&(databuf[i])) == -1) {
+                txdata = 0;
+                break;
+            }
+            i++;
+        }
+        if (i>0) {
+            can_transmit(MyCanId+1, i, databuf);
+        }
+    }
+}
diff --git a/src/stm32/stm32f0_can.h b/src/stm32/stm32f0_can.h
new file mode 100644
index 00000000..6b3cb2a4
--- /dev/null
+++ b/src/stm32/stm32f0_can.h
@@ -0,0 +1,17 @@
+#ifndef CORE_INC_CAN_H_
+#define CORE_INC_CAN_H_
+
+// Read UUID  (6bytes)
+#define PKT_ID_UUID (0x321)
+// Set address (2bytes) to UUID (6b)
+#define PKT_ID_SET (0x322)
+// UUID response from slave  (6bytes)
+#define PKT_ID_UUID_RESP (0x323)
+
+#define STM32_UUID_ADDR (0x1FFFF7AC)
+#define SHORT_UUID_LEN (6)
+
+void CanInit(void);
+void CanTransmit(uint32_t id, uint32_t dlc, uint8_t *pkt);
+
+#endif /* CORE_INC_CAN_H_ */