diff options
Diffstat (limited to 'drivers/comedi/drivers/ni_labpc_isadma.c')
| -rw-r--r-- | drivers/comedi/drivers/ni_labpc_isadma.c | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/drivers/comedi/drivers/ni_labpc_isadma.c b/drivers/comedi/drivers/ni_labpc_isadma.c new file mode 100644 index 000000000000..a551aca6e615 --- /dev/null +++ b/drivers/comedi/drivers/ni_labpc_isadma.c @@ -0,0 +1,181 @@ +// 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"); |