/*
    ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
                 2011,2012,2013 Giovanni Di Sirio.

    This file is part of ChibiOS/RT.

    ChibiOS/RT is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    ChibiOS/RT is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/**
 * @file    STM32F0xx/stm32_dma.c
 * @brief   DMA helper driver code.
 *
 * @addtogroup STM32F0xx_DMA
 * @details DMA sharing helper driver. In the STM32 the DMA streams are a
 *          shared resource, this driver allows to allocate and free DMA
 *          streams at runtime in order to allow all the other device
 *          drivers to coordinate the access to the resource.
 * @note    The DMA ISR handlers are all declared into this module because
 *          sharing, the various device drivers can associate a callback to
 *          ISRs when allocating streams.
 * @{
 */

#include "ch.h"
#include "hal.h"

/* The following macro is only defined if some driver requiring DMA services
   has been enabled.*/
#if defined(STM32_DMA_REQUIRED) || defined(__DOXYGEN__)

/*===========================================================================*/
/* Driver local definitions.                                                 */
/*===========================================================================*/

/**
 * @brief   Mask of the DMA1 streams in @p dma_streams_mask.
 */
#define STM32_DMA1_STREAMS_MASK     0x0000007F

/**
 * @brief   Mask of the DMA2 streams in @p dma_streams_mask.
 */
#define STM32_DMA2_STREAMS_MASK     0x00000F80

/**
 * @brief   Post-reset value of the stream CCR register.
 */
#define STM32_DMA_CCR_RESET_VALUE   0x00000000

/*===========================================================================*/
/* Driver exported variables.                                                */
/*===========================================================================*/

/**
 * @brief   DMA streams descriptors.
 * @details This table keeps the association between an unique stream
 *          identifier and the involved physical registers.
 * @note    Don't use this array directly, use the appropriate wrapper macros
 *          instead: @p STM32_DMA1_STREAM1, @p STM32_DMA1_STREAM2 etc.
 */
const stm32_dma_stream_t _stm32_dma_streams[STM32_DMA_STREAMS] = {
  {DMA1_Channel1, &DMA1->IFCR, 0, 0, DMA1_Channel1_IRQn},
  {DMA1_Channel2, &DMA1->IFCR, 4, 1, DMA1_Channel2_3_IRQn},
  {DMA1_Channel3, &DMA1->IFCR, 8, 2, DMA1_Channel2_3_IRQn},
  {DMA1_Channel4, &DMA1->IFCR, 12, 3, DMA1_Channel4_5_IRQn},
  {DMA1_Channel5, &DMA1->IFCR, 16, 4, DMA1_Channel4_5_IRQn}
};

/*===========================================================================*/
/* Driver local variables and types.                                         */
/*===========================================================================*/

/**
 * @brief   DMA ISR redirector type.
 */
typedef struct {
  stm32_dmaisr_t        dma_func;       /**< @brief DMA callback function.  */
  void                  *dma_param;     /**< @brief DMA callback parameter. */
} dma_isr_redir_t;

/**
 * @brief   Mask of the allocated streams.
 */
static uint32_t dma_streams_mask;

/**
 * @brief   DMA IRQ redirectors.
 */
static dma_isr_redir_t dma_isr_redir[STM32_DMA_STREAMS];

/*===========================================================================*/
/* Driver local functions.                                                   */
/*===========================================================================*/

/*===========================================================================*/
/* Driver interrupt handlers.                                                */
/*===========================================================================*/

/**
 * @brief   DMA1 stream 1 shared interrupt handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(DMA1_Ch1_IRQHandler) {
  uint32_t flags;

  CH_IRQ_PROLOGUE();

  flags = (DMA1->ISR >> 0) & STM32_DMA_ISR_MASK;
  DMA1->IFCR = STM32_DMA_ISR_MASK << 0;
  if (dma_isr_redir[0].dma_func)
    dma_isr_redir[0].dma_func(dma_isr_redir[0].dma_param, flags);

  CH_IRQ_EPILOGUE();
}

/**
 * @brief   DMA1 streams 2 and 3 shared interrupt handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(DMA1_Ch2_3_IRQHandler) {
  uint32_t flags;

  CH_IRQ_PROLOGUE();

  /* Check on channel 2.*/
  flags = (DMA1->ISR >> 4) & STM32_DMA_ISR_MASK;
  if (flags & STM32_DMA_ISR_MASK) {
    DMA1->IFCR = STM32_DMA_ISR_MASK << 4;
    if (dma_isr_redir[1].dma_func)
      dma_isr_redir[1].dma_func(dma_isr_redir[1].dma_param, flags);
  }

  /* Check on channel 3.*/
  flags = (DMA1->ISR >> 8) & STM32_DMA_ISR_MASK;
  if (flags & STM32_DMA_ISR_MASK) {
    DMA1->IFCR = STM32_DMA_ISR_MASK << 8;
    if (dma_isr_redir[2].dma_func)
      dma_isr_redir[2].dma_func(dma_isr_redir[2].dma_param, flags);
  }

  CH_IRQ_EPILOGUE();
}

/**
 * @brief   DMA1 streams 4 and 5 shared interrupt handler.
 *
 * @isr
 */
CH_IRQ_HANDLER(DMA1_Ch4_5_IRQHandler) {
  uint32_t flags;

  CH_IRQ_PROLOGUE();

  /* Check on channel 4.*/
  flags = (DMA1->ISR >> 12) & STM32_DMA_ISR_MASK;
  if (flags & STM32_DMA_ISR_MASK) {
    DMA1->IFCR = STM32_DMA_ISR_MASK << 12;
    if (dma_isr_redir[3].dma_func)
      dma_isr_redir[3].dma_func(dma_isr_redir[3].dma_param, flags);
  }

  /* Check on channel 5.*/
  flags = (DMA1->ISR >> 16) & STM32_DMA_ISR_MASK;
  if (flags & STM32_DMA_ISR_MASK) {
    DMA1->IFCR = STM32_DMA_ISR_MASK << 16;
    if (dma_isr_redir[4].dma_func)
      dma_isr_redir[4].dma_func(dma_isr_redir[4].dma_param, flags);
  }

  CH_IRQ_EPILOGUE();
}

/*===========================================================================*/
/* Driver exported functions.                                                */
/*===========================================================================*/

/**
 * @brief   STM32 DMA helper initialization.
 *
 * @init
 */
void dmaInit(void) {
  int i;

  dma_streams_mask = 0;
  for (i = 0; i < STM32_DMA_STREAMS; i++) {
    _stm32_dma_streams[i].channel->CCR = 0;
    dma_isr_redir[i].dma_func = NULL;
  }
  DMA1->IFCR = 0xFFFFFFFF;
}

/**
 * @brief   Allocates a DMA stream.
 * @details The stream is allocated and, if required, the DMA clock enabled.
 *          The function also enables the IRQ vector associated to the stream
 *          and initializes its priority.
 * @pre     The stream must not be already in use or an error is returned.
 * @post    The stream is allocated and the default ISR handler redirected
 *          to the specified function.
 * @post    The stream ISR vector is enabled and its priority configured.
 * @post    The stream must be freed using @p dmaStreamRelease() before it can
 *          be reused with another peripheral.
 * @post    The stream is in its post-reset state.
 * @note    This function can be invoked in both ISR or thread context.
 *
 * @param[in] dmastp    pointer to a stm32_dma_stream_t structure
 * @param[in] priority  IRQ priority mask for the DMA stream
 * @param[in] func      handling function pointer, can be @p NULL
 * @param[in] param     a parameter to be passed to the handling function
 * @return              The operation status.
 * @retval FALSE        no error, stream taken.
 * @retval TRUE         error, stream already taken.
 *
 * @special
 */
bool_t dmaStreamAllocate(const stm32_dma_stream_t *dmastp,
                         uint32_t priority,
                         stm32_dmaisr_t func,
                         void *param) {

  chDbgCheck(dmastp != NULL, "dmaAllocate");

  /* Checks if the stream is already taken.*/
  if ((dma_streams_mask & (1 << dmastp->selfindex)) != 0)
    return TRUE;

  /* Marks the stream as allocated.*/
  dma_isr_redir[dmastp->selfindex].dma_func  = func;
  dma_isr_redir[dmastp->selfindex].dma_param = param;
  dma_streams_mask |= (1 << dmastp->selfindex);

  /* Enabling DMA clocks required by the current streams set.*/
  if ((dma_streams_mask & STM32_DMA1_STREAMS_MASK) != 0)
    rccEnableDMA1(FALSE);

  /* Putting the stream in a safe state.*/
  dmaStreamDisable(dmastp);
  dmastp->channel->CCR = STM32_DMA_CCR_RESET_VALUE;

  /* Enables the associated IRQ vector if a callback is defined.*/
  if (func != NULL)
    nvicEnableVector(dmastp->vector, CORTEX_PRIORITY_MASK(priority));

  return FALSE;
}

/**
 * @brief   Releases a DMA stream.
 * @details The stream is freed and, if required, the DMA clock disabled.
 *          Trying to release a unallocated stream is an illegal operation
 *          and is trapped if assertions are enabled.
 * @pre     The stream must have been allocated using @p dmaStreamAllocate().
 * @post    The stream is again available.
 * @note    This function can be invoked in both ISR or thread context.
 *
 * @param[in] dmastp    pointer to a stm32_dma_stream_t structure
 *
 * @special
 */
void dmaStreamRelease(const stm32_dma_stream_t *dmastp) {

  chDbgCheck(dmastp != NULL, "dmaRelease");

  /* Check if the streams is not taken.*/
  chDbgAssert((dma_streams_mask & (1 << dmastp->selfindex)) != 0,
              "dmaRelease(), #1", "not allocated");

  /* Disables the associated IRQ vector.*/
  nvicDisableVector(dmastp->vector);

  /* Marks the stream as not allocated.*/
  dma_streams_mask &= ~(1 << dmastp->selfindex);

  /* Shutting down clocks that are no more required, if any.*/
  if ((dma_streams_mask & STM32_DMA1_STREAMS_MASK) == 0)
    rccDisableDMA1(FALSE);
}

#endif /* STM32_DMA_REQUIRED */

/** @} */