diff options
Diffstat (limited to 'drivers/staging/comedi/drivers/ni_labpc_isadma.c')
| -rw-r--r-- | drivers/staging/comedi/drivers/ni_labpc_isadma.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/drivers/staging/comedi/drivers/ni_labpc_isadma.c b/drivers/staging/comedi/drivers/ni_labpc_isadma.c new file mode 100644 index 000000000000..2149596830af --- /dev/null +++ b/drivers/staging/comedi/drivers/ni_labpc_isadma.c @@ -0,0 +1,226 @@ +/* + * 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> + * + * This program 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 2 of the License, or + * (at your option) any later version. + * + * This program 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. + */ + +#include <linux/module.h> +#include <linux/slab.h> +#include "../comedidev.h" + +#include <asm/dma.h> + +#include "comedi_fc.h" +#include "ni_labpc.h" +#include "ni_labpc_regs.h" +#include "ni_labpc_isadma.h" + +/* size in bytes of dma buffer */ +static const int dma_buffer_size = 0xff00; +/* 2 bytes per sample */ +static const int sample_size = 2; + +/* utility function that suggests a dma transfer size in bytes */ +static unsigned int labpc_suggest_transfer_size(const struct comedi_cmd *cmd) +{ + 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 > dma_buffer_size) + size = dma_buffer_size - dma_buffer_size % sample_size; + 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_cmd *cmd = &s->async->cmd; + unsigned long irq_flags; + + irq_flags = claim_dma_lock(); + disable_dma(devpriv->dma_chan); + /* clear flip-flop to make sure 2-byte registers for + * count and address get set correctly */ + clear_dma_ff(devpriv->dma_chan); + set_dma_addr(devpriv->dma_chan, devpriv->dma_addr); + /* set appropriate size of transfer */ + devpriv->dma_transfer_size = labpc_suggest_transfer_size(cmd); + if (cmd->stop_src == TRIG_COUNT && + devpriv->count * sample_size < devpriv->dma_transfer_size) + devpriv->dma_transfer_size = devpriv->count * sample_size; + set_dma_count(devpriv->dma_chan, devpriv->dma_transfer_size); + enable_dma(devpriv->dma_chan); + release_dma_lock(irq_flags); + /* 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_subdevice *s = dev->read_subdev; + struct comedi_async *async = s->async; + int status; + unsigned long flags; + unsigned int max_points, num_points, residue, leftover; + int i; + + status = devpriv->stat1; + + flags = claim_dma_lock(); + disable_dma(devpriv->dma_chan); + /* clear flip-flop to make sure 2-byte registers for + * count and address get set correctly */ + clear_dma_ff(devpriv->dma_chan); + + /* figure out how many points to read */ + max_points = devpriv->dma_transfer_size / sample_size; + /* residue is the number of points 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 = get_dma_residue(devpriv->dma_chan) / sample_size; + num_points = max_points - residue; + if (devpriv->count < num_points && async->cmd.stop_src == TRIG_COUNT) + num_points = devpriv->count; + + /* figure out how many points will be stored next time */ + leftover = 0; + if (async->cmd.stop_src != TRIG_COUNT) { + leftover = devpriv->dma_transfer_size / sample_size; + } else if (devpriv->count > num_points) { + leftover = devpriv->count - num_points; + if (leftover > max_points) + leftover = max_points; + } + + /* write data to comedi buffer */ + for (i = 0; i < num_points; i++) + cfc_write_to_buffer(s, devpriv->dma_buffer[i]); + + if (async->cmd.stop_src == TRIG_COUNT) + devpriv->count -= num_points; + + /* set address and count for next transfer */ + set_dma_addr(devpriv->dma_chan, devpriv->dma_addr); + set_dma_count(devpriv->dma_chan, leftover * sample_size); + release_dma_lock(flags); + + async->events |= COMEDI_CB_BLOCK; +} +EXPORT_SYMBOL_GPL(labpc_drain_dma); + +static void handle_isa_dma(struct comedi_device *dev) +{ + struct labpc_private *devpriv = dev->private; + + labpc_drain_dma(dev); + + enable_dma(devpriv->dma_chan); + + /* clear dma tc interrupt */ + devpriv->write_byte(0x1, dev->iobase + DMATC_CLEAR_REG); +} + +void labpc_handle_dma_status(struct comedi_device *dev) +{ + const struct labpc_boardinfo *board = comedi_board(dev); + 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); + +int labpc_init_dma_chan(struct comedi_device *dev, unsigned int dma_chan) +{ + struct labpc_private *devpriv = dev->private; + void *dma_buffer; + unsigned long dma_flags; + int ret; + + if (dma_chan != 1 && dma_chan != 3) + return -EINVAL; + + dma_buffer = kmalloc(dma_buffer_size, GFP_KERNEL | GFP_DMA); + if (!dma_buffer) + return -ENOMEM; + + ret = request_dma(dma_chan, dev->board_name); + if (ret) { + kfree(dma_buffer); + return ret; + } + + devpriv->dma_buffer = dma_buffer; + devpriv->dma_chan = dma_chan; + devpriv->dma_addr = virt_to_bus(devpriv->dma_buffer); + + dma_flags = claim_dma_lock(); + disable_dma(devpriv->dma_chan); + set_dma_mode(devpriv->dma_chan, DMA_MODE_READ); + release_dma_lock(dma_flags); + + return 0; +} +EXPORT_SYMBOL_GPL(labpc_init_dma_chan); + +void labpc_free_dma_chan(struct comedi_device *dev) +{ + struct labpc_private *devpriv = dev->private; + + kfree(devpriv->dma_buffer); + devpriv->dma_buffer = NULL; + if (devpriv->dma_chan) { + free_dma(devpriv->dma_chan); + devpriv->dma_chan = 0; + } +} +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 http://www.comedi.org"); +MODULE_DESCRIPTION("Comedi NI Lab-PC ISA DMA support"); +MODULE_LICENSE("GPL"); |