diff options
Diffstat (limited to 'bsps/arm/lpc24xx/start/dma.c')
-rw-r--r-- | bsps/arm/lpc24xx/start/dma.c | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/bsps/arm/lpc24xx/start/dma.c b/bsps/arm/lpc24xx/start/dma.c new file mode 100644 index 0000000000..a67760ad3e --- /dev/null +++ b/bsps/arm/lpc24xx/start/dma.c @@ -0,0 +1,102 @@ +/** + * @file + * + * @ingroup lpc24xx_dma + * + * @brief Direct memory access (DMA) support. + */ + +/* + * Copyright (c) 2008-2011 embedded brains GmbH. All rights reserved. + * + * embedded brains GmbH + * Obere Lagerstr. 30 + * 82178 Puchheim + * Germany + * <rtems@embedded-brains.de> + * + * 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 <rtems/endian.h> + +#include <bsp/lpc24xx.h> +#include <bsp/dma.h> +#include <bsp/io.h> + +/** + * @brief Table that indicates if a channel is currently occupied. + */ +static bool lpc24xx_dma_channel_occupation [GPDMA_CH_NUMBER]; + +void lpc24xx_dma_initialize(void) +{ + /* Enable module power */ + lpc24xx_module_enable(LPC24XX_MODULE_GPDMA, LPC24XX_MODULE_PCLK_DEFAULT); + + /* Disable module */ + GPDMA_CONFIG = 0; + + /* Reset registers */ + GPDMA_SOFT_SREQ = 0; + GPDMA_SOFT_BREQ = 0; + GPDMA_SOFT_LSREQ = 0; + GPDMA_SOFT_LBREQ = 0; + GPDMA_SYNC = 0; + GPDMA_CH0_CFG = 0; + GPDMA_CH1_CFG = 0; + + /* Enable module */ + #if BYTE_ORDER == LITTLE_ENDIAN + GPDMA_CONFIG = GPDMA_CONFIG_EN; + #else + GPDMA_CONFIG = GPDMA_CONFIG_EN | GPDMA_CONFIG_MODE; + #endif +} + +rtems_status_code lpc24xx_dma_channel_obtain(unsigned channel) +{ + if (channel < GPDMA_CH_NUMBER) { + rtems_interrupt_level level; + bool occupation = true; + + rtems_interrupt_disable(level); + occupation = lpc24xx_dma_channel_occupation [channel]; + lpc24xx_dma_channel_occupation [channel] = true; + rtems_interrupt_enable(level); + + return occupation ? RTEMS_RESOURCE_IN_USE : RTEMS_SUCCESSFUL; + } else { + return RTEMS_INVALID_ID; + } +} + +void lpc24xx_dma_channel_release(unsigned channel) +{ + if (channel < GPDMA_CH_NUMBER) { + lpc24xx_dma_channel_occupation [channel] = false; + } +} + +void lpc24xx_dma_channel_disable(unsigned channel, bool force) +{ + if (channel < GPDMA_CH_NUMBER) { + volatile lpc24xx_dma_channel *ch = GPDMA_CH_BASE_ADDR(channel); + uint32_t cfg = ch->cfg; + + if (!force) { + /* Halt */ + ch->cfg |= GPDMA_CH_CFG_HALT; + + /* Wait for inactive */ + do { + cfg = ch->cfg; + } while ((cfg & GPDMA_CH_CFG_ACTIVE) != 0); + } + + /* Disable */ + ch->cfg &= ~GPDMA_CH_CFG_EN; + } +} |