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// SPDX-License-Identifier: GPL-2.0+
/*
* comedi/drivers/ni_labpc_isadma.c
* ISA DMA support for National Instruments Lab-PC series boards and
* compatibles.
*
* Extracted from ni_labpc.c:
* Copyright (C) 2001-2003 Frank Mori Hess <fmhess@users.sourceforge.net>
*/
#include <linux/module.h>
#include <linux/slab.h>
#include "../comedidev.h"
#include "comedi_isadma.h"
#include "ni_labpc.h"
#include "ni_labpc_regs.h"
#include "ni_labpc_isadma.h"
/* size in bytes of dma buffer */
#define LABPC_ISADMA_BUFFER_SIZE 0xff00
/* utility function that suggests a dma transfer size in bytes */
static unsigned int labpc_suggest_transfer_size(struct comedi_device *dev,
struct comedi_subdevice *s,
unsigned int maxbytes)
{
struct comedi_cmd *cmd = &s->async->cmd;
unsigned int sample_size = comedi_bytes_per_sample(s);
unsigned int size;
unsigned int freq;
if (cmd->convert_src == TRIG_TIMER)
freq = 1000000000 / cmd->convert_arg;
else
/* return some default value */
freq = 0xffffffff;
/* make buffer fill in no more than 1/3 second */
size = (freq / 3) * sample_size;
/* set a minimum and maximum size allowed */
if (size > maxbytes)
size = maxbytes;
else if (size < sample_size)
size = sample_size;
return size;
}
void labpc_setup_dma(struct comedi_device *dev, struct comedi_subdevice *s)
{
struct labpc_private *devpriv = dev->private;
struct comedi_isadma_desc *desc = &devpriv->dma->desc[0];
struct comedi_cmd *cmd = &s->async->cmd;
unsigned int sample_size = comedi_bytes_per_sample(s);
/* set appropriate size of transfer */
desc->size = labpc_suggest_transfer_size(dev, s, desc->maxsize);
if (cmd->stop_src == TRIG_COUNT &&
devpriv->count * sample_size < desc->size)
desc->size = devpriv->count * sample_size;
comedi_isadma_program(desc);
/* set CMD3 bits for caller to enable DMA and interrupt */
devpriv->cmd3 |= (CMD3_DMAEN | CMD3_DMATCINTEN);
}
EXPORT_SYMBOL_GPL(labpc_setup_dma);
void labpc_drain_dma(struct comedi_device *dev)
{
struct labpc_private *devpriv = dev->private;
struct comedi_isadma_desc *desc = &devpriv->dma->desc[0];
struct comedi_subdevice *s = dev->read_subdev;
struct comedi_async *async = s->async;
struct comedi_cmd *cmd = &async->cmd;
unsigned int max_samples = comedi_bytes_to_samples(s, desc->size);
unsigned int residue;
unsigned int nsamples;
unsigned int leftover;
/*
* residue is the number of bytes left to be done on the dma
* transfer. It should always be zero at this point unless
* the stop_src is set to external triggering.
*/
residue = comedi_isadma_disable(desc->chan);
/*
* Figure out how many samples to read for this transfer and
* how many will be stored for next time.
*/
nsamples = max_samples - comedi_bytes_to_samples(s, residue);
if (cmd->stop_src == TRIG_COUNT) {
if (devpriv->count <= nsamples) {
nsamples = devpriv->count;
leftover = 0;
} else {
leftover = devpriv->count - nsamples;
if (leftover > max_samples)
leftover = max_samples;
}
devpriv->count -= nsamples;
} else {
leftover = max_samples;
}
desc->size = comedi_samples_to_bytes(s, leftover);
comedi_buf_write_samples(s, desc->virt_addr, nsamples);
}
EXPORT_SYMBOL_GPL(labpc_drain_dma);
static void handle_isa_dma(struct comedi_device *dev)
{
struct labpc_private *devpriv = dev->private;
struct comedi_isadma_desc *desc = &devpriv->dma->desc[0];
labpc_drain_dma(dev);
if (desc->size)
comedi_isadma_program(desc);
/* clear dma tc interrupt */
devpriv->write_byte(dev, 0x1, DMATC_CLEAR_REG);
}
void labpc_handle_dma_status(struct comedi_device *dev)
{
const struct labpc_boardinfo *board = dev->board_ptr;
struct labpc_private *devpriv = dev->private;
/*
* if a dma terminal count of external stop trigger
* has occurred
*/
if (devpriv->stat1 & STAT1_GATA0 ||
(board->is_labpc1200 && devpriv->stat2 & STAT2_OUTA1))
handle_isa_dma(dev);
}
EXPORT_SYMBOL_GPL(labpc_handle_dma_status);
void labpc_init_dma_chan(struct comedi_device *dev, unsigned int dma_chan)
{
struct labpc_private *devpriv = dev->private;
/* only DMA channels 3 and 1 are valid */
if (dma_chan != 1 && dma_chan != 3)
return;
/* DMA uses 1 buffer */
devpriv->dma = comedi_isadma_alloc(dev, 1, dma_chan, dma_chan,
LABPC_ISADMA_BUFFER_SIZE,
COMEDI_ISADMA_READ);
}
EXPORT_SYMBOL_GPL(labpc_init_dma_chan);
void labpc_free_dma_chan(struct comedi_device *dev)
{
struct labpc_private *devpriv = dev->private;
if (devpriv)
comedi_isadma_free(devpriv->dma);
}
EXPORT_SYMBOL_GPL(labpc_free_dma_chan);
static int __init ni_labpc_isadma_init_module(void)
{
return 0;
}
module_init(ni_labpc_isadma_init_module);
static void __exit ni_labpc_isadma_cleanup_module(void)
{
}
module_exit(ni_labpc_isadma_cleanup_module);
MODULE_AUTHOR("Comedi https://www.comedi.org");
MODULE_DESCRIPTION("Comedi NI Lab-PC ISA DMA support");
MODULE_LICENSE("GPL");
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