Solution 11 interrupt

10-ConcurrencyAndSynchronization/README.md

@@ -0,0 +1,21 @@
+# Concurrency and synchronization
+
+## Homework
+
+**(based on MPU6050 driver)**
+
+_NB_:
+Communication with peripheral device on i2c is quite slow asynchronous process
+which responsiveness depends on the slave latency and bus utilisation.  
+Thus generally it's better to be done in background process.
+
+1. Move interaction with MPU6050 into separate thread.
+
+2. Protect static data of the driver (`g_mpu6050_data` in the master)
+for the case of concurrent access.
+
+3. Limit interaction with MPU6050 in case of frequent requests:  
+Define validity interval - if the latest read data is older than this threshold
+then new data reading is performed, otherwise previously read data is returned.  
+(This threshold should be configurable parameter with reasonable default.)
+

11-InterruptsHandling/README.md

@@ -0,0 +1,23 @@
+# Interrupts handling
+
+## Homework
+
+**(based on MPU6050 driver)**
+
+1. Setup handling of MPU6050 interrupts.
+- Configure interrupt request on MPU6050 (e.g. motion detection).
+- Connect interrupt output of the MPU6050 with Orange-Pi GPIO.
+- Configure GPIO as input.
+- Register handler for the MPU6050 interrupt.
+
+2. Implement deferred interrupt handler (e.g. in custom workqueue) to handle the request.
+- Read new measurements.
+- Implement measurements processing (e.g. the following or per your preference).
+  - filtering (e.g. moving average);
+  - integrating (for acc to get speed);
+  - determine trends;
+  - etc.
+
+3. Provide additional interface (e.g. in procfs) to read the processed data at once.
+
+_Note: Remember to synchronize all concurrent operations_

mpu6050/Makefile

@@ -0,0 +1,43 @@
+MODULE_NAME=mpu6050
+
+ifneq ($(KERNELRELEASE),)
+
+obj-m :=$(MODULE_NAME).o
+
+else
+
+ccflags-y := -Wall
+DT_SRCS=$(wildcard *.dts)
+DT_OBJS=$(DT_SRCS:.dts=.dtbo)
+DTC_FLAGS ?= -i $(DCT_EXTRA_PATH)
+
+
+.PHONY: all clean
+
+all: $(DT_OBJS)
+	$(MAKE) -C $(BUILD_KERNEL) M=$(PWD) modules
+
+clean:
+	$(MAKE) -C $(BUILD_KERNEL) M=$(PWD) clean
+	-rm ./*.dtbo
+
+
+$(DT_OBJS): $(DT_SRCS)
+	$(DTC) -@ -I dts -O dtb -o $@ $<
+
+
+upload_config:
+	ssh-copy-id -i ~/.ssh/id_rsa.pub $(SSH_ORANGE)
+	echo $(KERNEL_VERSION)
+	-ssh $(SSH_ORANGE) '[ ! -d "/lib/modules/$(KERNEL_VERSION)/kernel/drivers/" ] && mkdir -p "/lib/modules/$(KERNEL_VERSION)/kernel/drivers/"'
+
+upload_dtso: $(DT_OBJS)
+	-scp $< $(SSH_ORANGE):/boot/dtb/overlay/
+
+upload_module: $(MODULE_NAME).ko
+	-scp $< $(SSH_ORANGE):/lib/modules/$(KERNEL_VERSION)/kernel/drivers/
+	-ssh $(SSH_ORANGE) 'depmod'
+
+upload: upload_dtso upload_module
+
+endif

mpu6050/README.md

@@ -0,0 +1,8 @@
+# MPU6050 Practice. Kernel object module development
+
+## Homework
+
+1. Fix the errors in kernel module sources and developed dts.
+2. Provide precision 0.001 C for temperature.
+3. Measure the performance by getting all values in cycle during 1 second.
+4. Improve the performance and measure it.

mpu6050/build.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+export BUILD_KERNEL=$(pwd)/../../build/kernel_opi
+export KERNEL_VERSION=5.4.0-rc1-00258-g2d00aee21a5d
+export DTC=$BUILD_KERNEL/scripts/dtc/dtc
+export CROSS_COMPILE=$(pwd)/../../toolchain/gcc-linaro-7.4.1-2019.02-x86_64_arm-linux-gnueabihf/bin/arm-linux-gnueabihf-
+export ARCH=arm
+export [email protected]
+#export INCLUDE_DTS=/home/tymbys/WORK/GL/linux/arch/arm/boot/dts
+export DCT_EXTRA_PATH=/home/tymbys/WORK/GL/linux/
+
+
+make clean && make && make upload

mpu6050/mpu6050-regs.h

@@ -0,0 +1,49 @@
+#ifndef _MPU6050_REGS_H
+#define _MPU6050_REGS_H
+
+/* Registed addresses */
+#define REG_CONFIG			0x1A
+#define REG_GYRO_CONFIG		0x1B
+#define REG_ACCEL_CONFIG	0x1C
+#define REG_FIFO_EN			0x23
+#define REG_INT_PIN_CFG		0x37
+#define REG_INT_ENABLE		0x38
+#define REG_ACCEL_XOUT_H	0x3B
+#define REG_ACCEL_XOUT_L	0x3C
+#define REG_ACCEL_YOUT_H	0x3D
+#define REG_ACCEL_YOUT_L	0x3E
+#define REG_ACCEL_ZOUT_H	0x3F
+#define REG_ACCEL_ZOUT_L	0x40
+#define REG_TEMP_OUT_H		0x41
+#define REG_TEMP_OUT_L		0x42
+#define REG_GYRO_XOUT_H		0x43
+#define REG_GYRO_XOUT_L		0x44
+#define REG_GYRO_YOUT_H		0x45
+#define REG_GYRO_YOUT_L		0x46
+#define REG_GYRO_ZOUT_H		0x47
+#define REG_GYRO_ZOUT_L		0x48
+#define REG_USER_CTRL		0x6A
+#define REG_PWR_MGMT_1		0x6B
+#define REG_PWR_MGMT_2		0x6C
+#define REG_WHO_AM_I		0x75
+
+/* Register values */
+#define MPU6050_WHO_AM_I	0x68
+
+char init_table [][2] = {
+	{0x1A, 0},
+	{0x1B, 0},
+	{0x1C, 0},
+	{0x23, 0},
+	{0x6A, 0},
+	{0x6B, 0},
+	{0x6C, 0},
+	{0x1D, 0xff},
+	{0x1E, 0x01},
+	{0x69, 0x24},
+	{0x37, 0x1f},
+	{0x38, 0x80},
+	{0, 0}
+};
+
+#endif /* _MPU6050_REGS_H */