diff --git a/cpukit/include/rtems/gpio.h b/cpukit/include/rtems/gpio.h new file mode 100644 index 0000000..3d68c39 --- /dev/null +++ b/cpukit/include/rtems/gpio.h @@ -0,0 +1,64 @@ +/** + * @file rtems/gpio.h + * + * @brief Global GPIO definitions. + * + * This include the generalized definitions for GPIO + */ + +/** + * Copyright (c) 2015 Ketul Shah <ketulshah1993 at gmail.com> + * + * 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. + */ + +#ifndef _RTEMS_GPIO_H +#define _RTEMS_GPIO_H + +#ifdef __cplusplus +extern "C" { +#endif /* __cplusplus */ + +/* Returned Error Codes by function */ +#define GPIO_SUCCESSFUL 0 /* operation is OK */ +#define GPIO_UNKNOWN_PIN 1 /* pin not known by bsp */ +#define GPIO_UNCONFIGURED_PIN 2 /* pin unable to configure */ +#define GPIO_MISCONFIGURED_PIN 3 /* pin configuration can't match operation */ + +/* Possible GPIO Pin States */ +#define GPIO_PIN_STATE_UNCONFIGURED 0 +#define GPIO_PIN_STATE_DIGITAL_OUT 1 +#define GPIO_PIN_STATE_DIGITAL_IN 2 + +/** + * @brief Structure contains all the required members for GPIO access. + */ +typedef struct +{ + int pin_number;/* The pin number. */ + void* platform; /* Opaque hardware specific set up details. */ +} gpio_pin_handle; + +/** + * @brief Initializes the GPIO API. + */ +extern void rtems_gpio_initialize(void); +/** + * @brief Selects a GPIO pin for a digital output. + */ +extern int rtems_gpio_configure_pin_digital_out( + gpio_pin_handle *, unsigned int ); +/** + * @brief Turns on the given pin. + */ +extern int rtems_gpio_digital_set(gpio_pin_handle *); +/** + * @brief Turns off the given pin. + */ +extern int rtems_gpio_digital_clear(gpio_pin_handle *); +/** + * @brief currently configured pin is released and made UNCONFIGURED. + */ +extern int rtems_gpio_release_pin(gpio_pin_handle *); \ No newline at end of file
diff --git a/c/src/lib/libbsp/arm/beagle/gpio/gpio.c b/c/src/lib/libbsp/arm/beagle/gpio/gpio.c new file mode 100644 index 0000000..541d456 --- /dev/null +++ b/c/src/lib/libbsp/arm/beagle/gpio/gpio.c @@ -0,0 +1,210 @@ +/** + * @file + * + * @ingroup arm_beagle + * + * @brief Global BSP definitions. + */ + +/** + * Copyright (c) 2015 Ketul Shah <ketulshah1993 at gmail.com> + * + * 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 <libcpu/am335x.h> +#include <rtems.h> +#include <rtems/gpio.h> +#include <bsp/irq.h> +#include <bsp/beagleboneblack.h> +#include <bsp.h> +#include <stdlib.h> +#include <stdint.h> +#include <assert.h> + +/** + * @brief GPIO API mutex atributes. + */ +#define MUTEX_ATRIBUTES \ + ( RTEMS_LOCAL \ + | RTEMS_PRIORITY \ + | RTEMS_BINARY_SEMAPHORE \ + | RTEMS_INHERIT_PRIORITY \ + | RTEMS_NO_PRIORITY_CEILING \ + ) + +#define OBTAIN_LOCK(s) if(rtems_semaphore_obtain(s, \ + RTEMS_WAIT, \ + RTEMS_NO_TIMEOUT \ + ) != RTEMS_SUCCESSFUL) \ + printf("Semaphore not obtained\n"); + +#define RELEASE_LOCK(s) if(rtems_semaphore_release(s) != RTEMS_SUCCESSFUL) \ + printf("Semaphore not released\n"); + +/* GPIO bank pin number as per TRM of AM335X */ +static unsigned int gpio_bank_pin[GPIO_PIN_COUNT]; +/* GPIO bank determines register of AM335X */ +static unsigned int gpio_bank[GPIO_PIN_COUNT]; +/* Pin states for all GPIO pins*/ +static unsigned int gpio_pin_state[GPIO_PIN_COUNT]; +/* Variable for gpio initialization */ +static bool is_initialized = false; +/* Total number of gpio banks */ +static int gpio_bank_count = GPIO_PIN_COUNT / GPIO_PINS_PER_BANK; +/* Semaphore for avoiding race condition */ +static rtems_id bank_lock; + +static const uint32_t gpio_bank_addrs[] = + { AM335X_GPIO0, AM335X_GPIO1, AM335X_GPIO2, AM335X_GPIO3 }; + +static uint32_t inline get_pin_mask(unsigned int pin_number) +{ + return (1UL << gpio_bank_pin[pin_number]); +} + +static void inline reg_update_set(unsigned int pin_number,uint32_t reg) +{ + uint32_t gpioreg=gpio_bank[pin_number]+reg; + uint32_t gpioreg_val=mmio_read(gpioreg); + gpioreg_val |= get_pin_mask(pin_number); + mmio_write(gpioreg, gpioreg_val); +} + +static void inline reg_update_unset(unsigned int pin_number,uint32_t reg) +{ + uint32_t gpioreg=gpio_bank[pin_number]+reg; + uint32_t gpioreg_val=mmio_read(gpioreg); + gpioreg_val &= ~get_pin_mask(pin_number); + mmio_write(gpioreg, gpioreg_val); +} + +/** + * @brief Initializes the GPIO API. + * Allocates space to gpio_pin_state and sets pin state as UNCONFIGURED. + * Creates Semaphore for avoiding any race condition. + * If the API has already been initialized silently exits. + */ +void rtems_gpio_initialize(void) +{ + int i; + rtems_status_code status; + if ( is_initialized ) + return; + + is_initialized = true; + for ( i = 0; i < GPIO_PIN_COUNT; ++i ) { + gpio_pin_state[i] = GPIO_PIN_STATE_UNCONFIGURED; + } + /* Create GPIO bank Semaphores */ + status = rtems_semaphore_create( + rtems_build_name('G', 'L', 'C', 'K'), + 1, + MUTEX_ATRIBUTES, + 0, + &bank_lock + ); + if (status != RTEMS_SUCCESSFUL){ + printf("Semaphore not created\n"); + } +} + +/** + * @brief Configures a GPIO pin to perform a digital output. + * + * @retval GPIO_SUCCESSFUL Pin was configured successfully as output. + * @retval GPIO_UNKNOWN_PIN Pin is invalid or unknown. + * @retval GPIO_MISCONFIGURED_PIN Pin is already configured for another state. + */ +int rtems_gpio_configure_pin_digital_out( + gpio_pin_handle *gpio_pin_assign,unsigned int pin_number){ + + OBTAIN_LOCK(bank_lock); + if (pin_number >= GPIO_PIN_COUNT || pin_number < 0){ + RELEASE_LOCK(bank_lock); + return GPIO_UNKNOWN_PIN; + } + if ( + gpio_pin_state[gpio_pin_assign->pin_number] != GPIO_PIN_STATE_UNCONFIGURED && + gpio_pin_state[gpio_pin_assign->pin_number] != GPIO_PIN_STATE_DIGITAL_OUT){ + RELEASE_LOCK(bank_lock); + return GPIO_MISCONFIGURED_PIN; + } + + gpio_pin_state[gpio_pin_assign->pin_number] = GPIO_PIN_STATE_DIGITAL_OUT; + gpio_pin_assign->pin_number = pin_number; + gpio_bank_pin[pin_number] = pin_number % GPIO_PINS_PER_BANK; + gpio_bank[pin_number] = gpio_bank_addrs[pin_number/GPIO_PINS_PER_BANK]; + + reg_update_unset(gpio_pin_assign->pin_number,AM335X_GPIO_OE); + + RELEASE_LOCK(bank_lock); + return GPIO_SUCCESSFUL; +} + +/** + * @brief Gives an output GPIO pin the logical value of 1. + * @retval GPIO_SUCCESSFUL Pin was set successfully. + * @retval GPIO_MISCONFIGURED_PIN The received pin is not configured + * for digital output. + */ +int rtems_gpio_digital_set(gpio_pin_handle *gpio_pin_assign){ + + OBTAIN_LOCK(bank_lock); + if ( + gpio_pin_state[gpio_pin_assign->pin_number] != GPIO_PIN_STATE_DIGITAL_OUT){ + RELEASE_LOCK(bank_lock); + return GPIO_MISCONFIGURED_PIN; + } + + reg_update_set(gpio_pin_assign->pin_number,AM335X_GPIO_DATAOUT); + + RELEASE_LOCK(bank_lock); + return GPIO_SUCCESSFUL; +} + +/** + * @brief Gives an output GPIO pin the logical value of 0. + * @retval GPIO_SUCCESSFUL Pin was cleared successfully. + * @retval GPIO_MISCONFIGURED_PIN The received pin is not configured + * for digital output. + */ +int rtems_gpio_digital_clear(gpio_pin_handle *gpio_pin_assign){ + + OBTAIN_LOCK(bank_lock); + if ( + gpio_pin_state[gpio_pin_assign->pin_number] == GPIO_PIN_STATE_DIGITAL_OUT){ + RELEASE_LOCK(bank_lock); + return GPIO_MISCONFIGURED_PIN ; + } + + reg_update_unset(gpio_pin_assign->pin_number,AM335X_GPIO_DATAOUT); + + RELEASE_LOCK(bank_lock); + return GPIO_SUCCESSFUL; +} +/** + * @brief Releases currently configured pin and makes unused for repurposing. + * @retval GPIO_SUCCESSFUL Pin was released successfully or it is already + * UNCONFIGURED state. + * + */ +int rtems_gpio_release_pin(gpio_pin_handle *gpio_pin_assign){ + + OBTAIN_LOCK(bank_lock); + if ( + gpio_pin_state[gpio_pin_assign->pin_number] == GPIO_PIN_STATE_UNCONFIGURED){ + RELEASE_LOCK(bank_lock); + return GPIO_SUCCESSFUL; + } + + OBTAIN_LOCK(bank_lock); + + gpio_pin_state[gpio_pin_assign->pin_number] = GPIO_PIN_STATE_UNCONFIGURED; + reg_update_set(gpio_pin_assign->pin_number,AM335X_GPIO_OE); + + RELEASE_LOCK(bank_lock); + return GPIO_SUCCESSFUL; +} \ No newline at end of file _______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel
