From 35d28e880d1f4e0ae67fa7a7403849f10a052cba Mon Sep 17 00:00:00 2001
From: bondus <liquidpontus@yahoo.se>
Date: Mon, 10 Aug 2020 03:07:59 +0200
Subject: stm32: Improvements to CAN bus ID generation. And added a small fast
 hash library (#3165)

Improved CAM bus ID generation, there were issues with ID collisions.
Added a small fast hash library.

Signed-off-by: Pontus Borg <liquidpontus@yahoo.se>
---
 src/stm32/Makefile | 6 ++++--
 src/stm32/can.c    | 7 +++----
 2 files changed, 7 insertions(+), 6 deletions(-)

(limited to 'src/stm32')

diff --git a/src/stm32/Makefile b/src/stm32/Makefile
index 56f1581c..bd5017f2 100644
--- a/src/stm32/Makefile
+++ b/src/stm32/Makefile
@@ -17,7 +17,7 @@ CFLAGS-$(CONFIG_MACH_STM32F1) += -mcpu=cortex-m3 -Ilib/stm32f1/include
 CFLAGS-$(CONFIG_MACH_STM32F2) += -mcpu=cortex-m3 -Ilib/stm32f2/include
 CFLAGS-$(CONFIG_MACH_STM32F4) += -mcpu=cortex-m4 -Ilib/stm32f4/include
 CFLAGS-$(CONFIG_MACH_STM32F4) += -mfpu=fpv4-sp-d16 -mfloat-abi=hard
-CFLAGS += $(CFLAGS-y) -D$(MCU_UPPER) -mthumb -Ilib/cmsis-core
+CFLAGS += $(CFLAGS-y) -D$(MCU_UPPER) -mthumb -Ilib/cmsis-core -Ilib/fast-hash
 
 CFLAGS_klipper.elf += --specs=nano.specs --specs=nosys.specs
 CFLAGS_klipper.elf += -T $(OUT)src/generic/armcm_link.ld
@@ -46,9 +46,11 @@ src-$(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_CANSERIAL) += stm32/can.c
+can-src-$(CONFIG_CANSERIAL) += stm32/can.c ../lib/fast-hash/fasthash.c
 src-$(CONFIG_CANSERIAL) += $(can-src-y) generic/serial_irq.c
 
+dirs-$(CONFIG_CANSERIAL) += lib/fast-hash
+
 # Binary output file rules
 target-y += $(OUT)klipper.bin
 
diff --git a/src/stm32/can.c b/src/stm32/can.c
index 7e3d75f1..d0e84908 100644
--- a/src/stm32/can.c
+++ b/src/stm32/can.c
@@ -15,6 +15,7 @@
 #include "sched.h" // DECL_INIT
 #include <string.h>
 #include "can.h"
+#include <fasthash.h>
 
 #if (CONFIG_CAN_PINS_PA11_PA12)
 DECL_CONSTANT_STR("RESERVE_PINS_CAN", "PA11,PA12");
@@ -151,10 +152,8 @@ static void can_transmit(uint32_t id, uint32_t dlc, uint8_t *pkt)
 // 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*)(UID_BASE+i)) ^
-                *((uint8_t*)(UID_BASE+i+SHORT_UUID_LEN));
-    }
+    uint64_t hash = fasthash64((uint8_t*)UID_BASE, 12, 0xA16231A7);
+    memcpy(u, &hash, SHORT_UUID_LEN);
 }
 
 static void can_uuid_resp(void)
-- 
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