From 61e7c698a44137afbc1447ed328b14a0d9e55016 Mon Sep 17 00:00:00 2001 From: Andre Marques Date: Mon, 27 Jul 2015 17:01:44 +0100 Subject: Raspberry Pi implementation for the RTEMS GPIO API. Added support for the new RTEMS GPIO API functions. Test cases can be found in https://github.com/asuol/RTEMS_rpi_testing/tree/master/GPIO --- c/src/lib/libbsp/arm/raspberrypi/gpio/rpi-gpio.c | 329 +++++++++++++++++++++++ 1 file changed, 329 insertions(+) create mode 100644 c/src/lib/libbsp/arm/raspberrypi/gpio/rpi-gpio.c (limited to 'c/src/lib/libbsp/arm/raspberrypi/gpio/rpi-gpio.c') diff --git a/c/src/lib/libbsp/arm/raspberrypi/gpio/rpi-gpio.c b/c/src/lib/libbsp/arm/raspberrypi/gpio/rpi-gpio.c new file mode 100644 index 0000000000..bd37e67765 --- /dev/null +++ b/c/src/lib/libbsp/arm/raspberrypi/gpio/rpi-gpio.c @@ -0,0 +1,329 @@ +/** + * @file rpi-gpio.c + * + * @ingroup raspberrypi_gpio + * + * @brief Support for the Raspberry PI GPIO. + */ + +/* + * Copyright (c) 2014-2015 Andre Marques + * + * The license and distribution terms for this file may be + * found in the file LICENSE in this distribution or at + * http://www.rtems.org/license/LICENSE. + */ + +#include +#include +#include +#include + +#include + +/* Calculates a bitmask to assign an alternate function to a given pin. */ +#define SELECT_PIN_FUNCTION(fn, pn) (fn << ((pn % 10) * 3)) + +rtems_gpio_specific_data alt_func_def[] = { + {.io_function = RPI_ALT_FUNC_0, .pin_data = NULL}, + {.io_function = RPI_ALT_FUNC_1, .pin_data = NULL}, + {.io_function = RPI_ALT_FUNC_2, .pin_data = NULL}, + {.io_function = RPI_ALT_FUNC_3, .pin_data = NULL}, + {.io_function = RPI_ALT_FUNC_4, .pin_data = NULL}, + {.io_function = RPI_ALT_FUNC_5, .pin_data = NULL} +}; + +/* Raspberry Pi 1 Revision 2 gpio interface definitions. */ +#include "gpio-interfaces-pi1-rev2.c" + +/* Waits a number of CPU cycles. */ +static void arm_delay(uint8_t cycles) +{ + uint8_t i; + + for ( i = 0; i < cycles; ++i ) { + asm volatile("nop"); + } +} + +static rtems_status_code rpi_select_pin_function( + uint32_t bank, + uint32_t pin, + uint32_t type +) { + /* Calculate the pin function select register address. */ + volatile unsigned int *pin_addr = (unsigned int *) BCM2835_GPIO_REGS_BASE + + (pin / 10); + + if ( type == RPI_DIGITAL_IN ) { + *(pin_addr) &= ~SELECT_PIN_FUNCTION(RPI_DIGITAL_IN, pin); + } + else { + *(pin_addr) |= SELECT_PIN_FUNCTION(type, pin); + } + + return RTEMS_SUCCESSFUL; +} + +rtems_status_code rtems_gpio_bsp_multi_set(uint32_t bank, uint32_t bitmask) +{ + BCM2835_REG(BCM2835_GPIO_GPSET0) = bitmask; + + return RTEMS_SUCCESSFUL; +} + +rtems_status_code rtems_gpio_bsp_multi_clear(uint32_t bank, uint32_t bitmask) +{ + BCM2835_REG(BCM2835_GPIO_GPCLR0) = bitmask; + + return RTEMS_SUCCESSFUL; +} + +uint32_t rtems_gpio_bsp_multi_read(uint32_t bank, uint32_t bitmask) +{ + return (BCM2835_REG(BCM2835_GPIO_GPLEV0) & bitmask); +} + +rtems_status_code rtems_gpio_bsp_set(uint32_t bank, uint32_t pin) +{ + BCM2835_REG(BCM2835_GPIO_GPSET0) = (1 << pin); + + return RTEMS_SUCCESSFUL; +} + +rtems_status_code rtems_gpio_bsp_clear(uint32_t bank, uint32_t pin) +{ + BCM2835_REG(BCM2835_GPIO_GPCLR0) = (1 << pin); + + return RTEMS_SUCCESSFUL; +} + +uint8_t rtems_gpio_bsp_get_value(uint32_t bank, uint32_t pin) +{ + return (BCM2835_REG(BCM2835_GPIO_GPLEV0) & (1 << pin)); +} + +rtems_status_code rtems_gpio_bsp_select_input( + uint32_t bank, + uint32_t pin, + void *bsp_specific +) { + return rpi_select_pin_function(bank, pin, RPI_DIGITAL_IN); +} + +rtems_status_code rtems_gpio_bsp_select_output( + uint32_t bank, + uint32_t pin, + void *bsp_specific +) { + return rpi_select_pin_function(bank, pin, RPI_DIGITAL_OUT); +} + +rtems_status_code rtems_bsp_select_specific_io( + uint32_t bank, + uint32_t pin, + uint32_t function, + void *pin_data +) { + return rpi_select_pin_function(bank, pin, function); +} + +rtems_status_code rtems_gpio_bsp_set_resistor_mode( + uint32_t bank, + uint32_t pin, + rtems_gpio_pull_mode mode +) { + /* Set control signal. */ + switch ( mode ) { + case PULL_UP: + BCM2835_REG(BCM2835_GPIO_GPPUD) = (1 << 1); + break; + case PULL_DOWN: + BCM2835_REG(BCM2835_GPIO_GPPUD) = (1 << 0); + break; + case NO_PULL_RESISTOR: + BCM2835_REG(BCM2835_GPIO_GPPUD) = 0; + break; + default: + return RTEMS_UNSATISFIED; + } + + /* Wait 150 cyles, as per BCM2835 documentation. */ + arm_delay(150); + + /* Setup clock for the control signal. */ + BCM2835_REG(BCM2835_GPIO_GPPUDCLK0) = (1 << pin); + + arm_delay(150); + + /* Remove the control signal. */ + BCM2835_REG(BCM2835_GPIO_GPPUD) = 0; + + /* Remove the clock. */ + BCM2835_REG(BCM2835_GPIO_GPPUDCLK0) = 0; + + return RTEMS_SUCCESSFUL; +} + +rtems_vector_number rtems_gpio_bsp_get_vector(uint32_t bank) +{ + return BCM2835_IRQ_ID_GPIO_0; +} + +uint32_t rtems_gpio_bsp_interrupt_line(rtems_vector_number vector) +{ + uint32_t event_status; + + /* Retrieve the interrupt event status. */ + event_status = BCM2835_REG(BCM2835_GPIO_GPEDS0); + + /* Clear the interrupt line. */ + BCM2835_REG(BCM2835_GPIO_GPEDS0) = event_status; + + return event_status; +} + +rtems_status_code rtems_bsp_enable_interrupt( + uint32_t bank, + uint32_t pin, + rtems_gpio_interrupt interrupt +) { + switch ( interrupt ) { + case FALLING_EDGE: + /* Enables asynchronous falling edge detection. */ + BCM2835_REG(BCM2835_GPIO_GPAFEN0) |= (1 << pin); + break; + case RISING_EDGE: + /* Enables asynchronous rising edge detection. */ + BCM2835_REG(BCM2835_GPIO_GPAREN0) |= (1 << pin); + break; + case BOTH_EDGES: + /* Enables asynchronous falling edge detection. */ + BCM2835_REG(BCM2835_GPIO_GPAFEN0) |= (1 << pin); + + /* Enables asynchronous rising edge detection. */ + BCM2835_REG(BCM2835_GPIO_GPAREN0) |= (1 << pin); + break; + case LOW_LEVEL: + /* Enables pin low level detection. */ + BCM2835_REG(BCM2835_GPIO_GPLEN0) |= (1 << pin); + break; + case HIGH_LEVEL: + /* Enables pin high level detection. */ + BCM2835_REG(BCM2835_GPIO_GPHEN0) |= (1 << pin); + break; + case BOTH_LEVELS: + /* Enables pin low level detection. */ + BCM2835_REG(BCM2835_GPIO_GPLEN0) |= (1 << pin); + + /* Enables pin high level detection. */ + BCM2835_REG(BCM2835_GPIO_GPHEN0) |= (1 << pin); + break; + case NONE: + default: + return RTEMS_UNSATISFIED; + } + + return RTEMS_SUCCESSFUL; +} + +rtems_status_code rtems_bsp_disable_interrupt( + uint32_t bank, + uint32_t pin, + rtems_gpio_interrupt interrupt +) { + switch ( interrupt ) { + case FALLING_EDGE: + /* Disables asynchronous falling edge detection. */ + BCM2835_REG(BCM2835_GPIO_GPAFEN0) &= ~(1 << pin); + break; + case RISING_EDGE: + /* Disables asynchronous rising edge detection. */ + BCM2835_REG(BCM2835_GPIO_GPAREN0) &= ~(1 << pin); + break; + case BOTH_EDGES: + /* Disables asynchronous falling edge detection. */ + BCM2835_REG(BCM2835_GPIO_GPAFEN0) &= ~(1 << pin); + + /* Disables asynchronous rising edge detection. */ + BCM2835_REG(BCM2835_GPIO_GPAREN0) &= ~(1 << pin); + break; + case LOW_LEVEL: + /* Disables pin low level detection. */ + BCM2835_REG(BCM2835_GPIO_GPLEN0) &= ~(1 << pin); + break; + case HIGH_LEVEL: + /* Disables pin high level detection. */ + BCM2835_REG(BCM2835_GPIO_GPHEN0) &= ~(1 << pin); + break; + case BOTH_LEVELS: + /* Disables pin low level detection. */ + BCM2835_REG(BCM2835_GPIO_GPLEN0) &= ~(1 << pin); + + /* Disables pin high level detection. */ + BCM2835_REG(BCM2835_GPIO_GPHEN0) &= ~(1 << pin); + break; + case NONE: + default: + return RTEMS_UNSATISFIED; + } + + return RTEMS_SUCCESSFUL; +} + +rtems_status_code rpi_gpio_select_jtag(void) +{ + return rtems_gpio_multi_select(jtag_config, JTAG_PIN_COUNT); +} + +rtems_status_code rpi_gpio_select_spi(void) +{ + return rtems_gpio_multi_select(spi_config, SPI_PIN_COUNT); +} + +rtems_status_code rpi_gpio_select_i2c(void) +{ + return rtems_gpio_multi_select(i2c_config, I2C_PIN_COUNT); +} + +rtems_status_code rtems_gpio_bsp_multi_select( + rtems_gpio_multiple_pin_select *pins, + uint32_t pin_count, + uint32_t select_bank +) { + uint32_t register_address; + uint32_t select_register; + uint8_t i; + + register_address = BCM2835_GPIO_REGS_BASE + (select_bank * 0x04); + + select_register = BCM2835_REG(register_address); + + for ( i = 0; i < pin_count; ++i ) { + if ( pins[i].function == DIGITAL_INPUT ) { + select_register &= + ~SELECT_PIN_FUNCTION(RPI_DIGITAL_IN, pins[i].pin_number); + } + else if ( pins[i].function == DIGITAL_OUTPUT ) { + select_register |= + SELECT_PIN_FUNCTION(RPI_DIGITAL_OUT, pins[i].pin_number); + } + else { /* BSP_SPECIFIC function. */ + select_register |= + SELECT_PIN_FUNCTION(pins[i].io_function, pins[i].pin_number); + } + } + + BCM2835_REG(register_address) = select_register; + + return RTEMS_SUCCESSFUL; +} + +rtems_status_code rtems_gpio_bsp_specific_group_operation( + uint32_t bank, + uint32_t *pins, + uint32_t pin_count, + void *arg +) { + return RTEMS_NOT_DEFINED; +} -- cgit v1.2.3