staging: comedi: comedi_isadma: introduce helper module for ISA DMA
Introduce a new helper module to consolidate all the ISA DMA code. This will allow removing the "depends on ISA_DMA_API" from the legacy drivers that can use DMA for async command support. This module is complete based on the various uses of ISA DMA in the comedi drivers. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten
Greg Kroah-Hartman
parent
5e5a21cf8e
commit
20a1ea7d6b
|
|
@ -1262,6 +1262,9 @@ config COMEDI_DAS08
|
|||
tristate
|
||||
select COMEDI_8255
|
||||
|
||||
config COMEDI_ISADMA
|
||||
tristate
|
||||
|
||||
config COMEDI_NI_LABPC
|
||||
tristate
|
||||
select COMEDI_8255
|
||||
|
|
|
|||
|
|
@ -3,6 +3,7 @@
|
|||
ccflags-$(CONFIG_COMEDI_DEBUG) := -DDEBUG
|
||||
|
||||
# Comedi "helper" modules
|
||||
obj-$(CONFIG_COMEDI_ISADMA) += comedi_isadma.o
|
||||
|
||||
# Comedi misc drivers
|
||||
obj-$(CONFIG_COMEDI_BOND) += comedi_bond.o
|
||||
|
|
|
|||
|
|
@ -0,0 +1,262 @@
|
|||
/*
|
||||
* COMEDI ISA DMA support functions
|
||||
* Copyright (c) 2014 H Hartley Sweeten <hsweeten@visionengravers.com>
|
||||
*
|
||||
* 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 <linux/delay.h>
|
||||
#include <linux/dma-mapping.h>
|
||||
#include <asm/dma.h>
|
||||
|
||||
#include "../comedidev.h"
|
||||
|
||||
#include "comedi_isadma.h"
|
||||
|
||||
/**
|
||||
* comedi_isadma_program - program and enable an ISA DMA transfer
|
||||
* @desc: the ISA DMA cookie to program and enable
|
||||
*/
|
||||
void comedi_isadma_program(struct comedi_isadma_desc *desc)
|
||||
{
|
||||
unsigned long flags;
|
||||
|
||||
flags = claim_dma_lock();
|
||||
clear_dma_ff(desc->chan);
|
||||
set_dma_mode(desc->chan, desc->mode);
|
||||
set_dma_addr(desc->chan, desc->hw_addr);
|
||||
set_dma_count(desc->chan, desc->size);
|
||||
enable_dma(desc->chan);
|
||||
release_dma_lock(flags);
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(comedi_isadma_program);
|
||||
|
||||
/**
|
||||
* comedi_isadma_disable - disable the ISA DMA channel
|
||||
* @dma_chan: the DMA channel to disable
|
||||
*
|
||||
* Returns the residue (remaining bytes) left in the DMA transfer.
|
||||
*/
|
||||
unsigned int comedi_isadma_disable(unsigned int dma_chan)
|
||||
{
|
||||
unsigned long flags;
|
||||
unsigned int residue;
|
||||
|
||||
flags = claim_dma_lock();
|
||||
disable_dma(dma_chan);
|
||||
residue = get_dma_residue(dma_chan);
|
||||
release_dma_lock(flags);
|
||||
|
||||
return residue;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(comedi_isadma_disable);
|
||||
|
||||
/**
|
||||
* comedi_isadma_disable_on_sample - disable the ISA DMA channel
|
||||
* @dma_chan: the DMA channel to disable
|
||||
* @size: the sample size (in bytes)
|
||||
*
|
||||
* Returns the residue (remaining bytes) left in the DMA transfer.
|
||||
*/
|
||||
unsigned int comedi_isadma_disable_on_sample(unsigned int dma_chan,
|
||||
unsigned int size)
|
||||
{
|
||||
int stalled = 0;
|
||||
unsigned long flags;
|
||||
unsigned int residue;
|
||||
unsigned int new_residue;
|
||||
|
||||
residue = comedi_isadma_disable(dma_chan);
|
||||
while (residue % size) {
|
||||
/* residue is a partial sample, enable DMA to allow more data */
|
||||
flags = claim_dma_lock();
|
||||
enable_dma(dma_chan);
|
||||
release_dma_lock(flags);
|
||||
|
||||
udelay(2);
|
||||
new_residue = comedi_isadma_disable(dma_chan);
|
||||
|
||||
/* is DMA stalled? */
|
||||
if (new_residue == residue) {
|
||||
stalled++;
|
||||
if (stalled > 10)
|
||||
break;
|
||||
}
|
||||
residue = new_residue;
|
||||
stalled = 0;
|
||||
}
|
||||
return residue;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(comedi_isadma_disable_on_sample);
|
||||
|
||||
/**
|
||||
* comedi_isadma_poll - poll the current DMA transfer
|
||||
* @dma: the ISA DMA to poll
|
||||
*
|
||||
* Returns the position (in bytes) of the current DMA transfer.
|
||||
*/
|
||||
unsigned int comedi_isadma_poll(struct comedi_isadma *dma)
|
||||
{
|
||||
struct comedi_isadma_desc *desc = &dma->desc[dma->cur_dma];
|
||||
unsigned long flags;
|
||||
unsigned int result;
|
||||
unsigned int result1;
|
||||
|
||||
flags = claim_dma_lock();
|
||||
clear_dma_ff(desc->chan);
|
||||
if (!isa_dma_bridge_buggy)
|
||||
disable_dma(desc->chan);
|
||||
result = get_dma_residue(desc->chan);
|
||||
/*
|
||||
* Read the counter again and choose higher value in order to
|
||||
* avoid reading during counter lower byte roll over if the
|
||||
* isa_dma_bridge_buggy is set.
|
||||
*/
|
||||
result1 = get_dma_residue(desc->chan);
|
||||
if (!isa_dma_bridge_buggy)
|
||||
enable_dma(desc->chan);
|
||||
release_dma_lock(flags);
|
||||
|
||||
if (result < result1)
|
||||
result = result1;
|
||||
if (result >= desc->size || result == 0)
|
||||
return 0;
|
||||
else
|
||||
return desc->size - result;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(comedi_isadma_poll);
|
||||
|
||||
/**
|
||||
* comedi_isadma_set_mode - set the ISA DMA transfer direction
|
||||
* @desc: the ISA DMA cookie to set
|
||||
* @dma_dir: the DMA direction
|
||||
*/
|
||||
void comedi_isadma_set_mode(struct comedi_isadma_desc *desc, char dma_dir)
|
||||
{
|
||||
desc->mode = (dma_dir == COMEDI_ISADMA_READ) ? DMA_MODE_READ
|
||||
: DMA_MODE_WRITE;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(comedi_isadma_set_mode);
|
||||
|
||||
/**
|
||||
* comedi_isadma_alloc - allocate and initialize the ISA DMA
|
||||
* @dev: comedi_device struct
|
||||
* @n_desc: the number of cookies to allocate
|
||||
* @dma_chan: DMA channel for the first cookie
|
||||
* @dma_chan2: DMA channel for the second cookie
|
||||
* @maxsize: the size of the buffer to allocate for each cookie
|
||||
* @dma_dir: the DMA direction
|
||||
*
|
||||
* Returns the allocated and initialized ISA DMA or NULL if anything fails.
|
||||
*/
|
||||
struct comedi_isadma *comedi_isadma_alloc(struct comedi_device *dev,
|
||||
int n_desc, unsigned int dma_chan1,
|
||||
unsigned int dma_chan2,
|
||||
unsigned int maxsize, char dma_dir)
|
||||
{
|
||||
struct comedi_isadma *dma = NULL;
|
||||
struct comedi_isadma_desc *desc;
|
||||
unsigned int dma_chans[2];
|
||||
int i;
|
||||
|
||||
if (n_desc < 1 || n_desc > 2)
|
||||
goto no_dma;
|
||||
|
||||
dma = kzalloc(sizeof(*dma), GFP_KERNEL);
|
||||
if (!dma)
|
||||
goto no_dma;
|
||||
|
||||
desc = kcalloc(n_desc, sizeof(*desc), GFP_KERNEL);
|
||||
if (!desc)
|
||||
goto no_dma;
|
||||
dma->desc = desc;
|
||||
dma->n_desc = n_desc;
|
||||
|
||||
dma_chans[0] = dma_chan1;
|
||||
if (dma_chan2 == 0 || dma_chan2 == dma_chan1)
|
||||
dma_chans[1] = dma_chan1;
|
||||
else
|
||||
dma_chans[1] = dma_chan2;
|
||||
|
||||
if (request_dma(dma_chans[0], dev->board_name))
|
||||
goto no_dma;
|
||||
dma->chan = dma_chans[0];
|
||||
if (dma_chans[1] != dma_chans[0]) {
|
||||
if (request_dma(dma_chans[1], dev->board_name))
|
||||
goto no_dma;
|
||||
}
|
||||
dma->chan2 = dma_chans[1];
|
||||
|
||||
for (i = 0; i < n_desc; i++) {
|
||||
desc = &dma->desc[i];
|
||||
desc->chan = dma_chans[i];
|
||||
desc->maxsize = maxsize;
|
||||
desc->virt_addr = dma_alloc_coherent(NULL, desc->maxsize,
|
||||
&desc->hw_addr,
|
||||
GFP_KERNEL);
|
||||
if (!desc->virt_addr)
|
||||
goto no_dma;
|
||||
comedi_isadma_set_mode(desc, dma_dir);
|
||||
}
|
||||
|
||||
return dma;
|
||||
|
||||
no_dma:
|
||||
comedi_isadma_free(dma);
|
||||
return NULL;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(comedi_isadma_alloc);
|
||||
|
||||
/**
|
||||
* comedi_isadma_free - free the ISA DMA
|
||||
* @dma: the ISA DMA to free
|
||||
*/
|
||||
void comedi_isadma_free(struct comedi_isadma *dma)
|
||||
{
|
||||
struct comedi_isadma_desc *desc;
|
||||
int i;
|
||||
|
||||
if (!dma)
|
||||
return;
|
||||
|
||||
if (dma->desc) {
|
||||
for (i = 0; i < dma->n_desc; i++) {
|
||||
desc = &dma->desc[i];
|
||||
if (desc->virt_addr)
|
||||
dma_free_coherent(NULL, desc->maxsize,
|
||||
desc->virt_addr, desc->hw_addr);
|
||||
}
|
||||
kfree(dma->desc);
|
||||
}
|
||||
if (dma->chan2 && dma->chan2 != dma->chan)
|
||||
free_dma(dma->chan2);
|
||||
if (dma->chan)
|
||||
free_dma(dma->chan);
|
||||
kfree(dma);
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(comedi_isadma_free);
|
||||
|
||||
static int __init comedi_isadma_init(void)
|
||||
{
|
||||
return 0;
|
||||
}
|
||||
module_init(comedi_isadma_init);
|
||||
|
||||
static void __exit comedi_isadma_exit(void)
|
||||
{
|
||||
}
|
||||
module_exit(comedi_isadma_exit);
|
||||
|
||||
MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
|
||||
MODULE_DESCRIPTION("Comedi ISA DMA support");
|
||||
MODULE_LICENSE("GPL");
|
||||
|
|
@ -0,0 +1,116 @@
|
|||
/*
|
||||
* COMEDI ISA DMA support functions
|
||||
* Copyright (c) 2014 H Hartley Sweeten <hsweeten@visionengravers.com>
|
||||
*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
#ifndef _COMEDI_ISADMA_H
|
||||
#define _COMEDI_ISADMA_H
|
||||
|
||||
/*
|
||||
* These are used to avoid issues when <asm/dma.h> and the DMA_MODE_
|
||||
* defines are not available.
|
||||
*/
|
||||
#define COMEDI_ISADMA_READ 0
|
||||
#define COMEDI_ISADMA_WRITE 1
|
||||
|
||||
/**
|
||||
* struct comedi_isadma_desc - cookie for ISA DMA
|
||||
* @virt_addr: virtual address of buffer
|
||||
* @hw_addr: hardware (bus) address of buffer
|
||||
* @chan: DMA channel
|
||||
* @maxsize: allocated size of buffer (in bytes)
|
||||
* @size: transfer size (in bytes)
|
||||
* @mode: DMA_MODE_READ or DMA_MODE_WRITE
|
||||
*/
|
||||
struct comedi_isadma_desc {
|
||||
void *virt_addr;
|
||||
dma_addr_t hw_addr;
|
||||
unsigned int chan;
|
||||
unsigned int maxsize;
|
||||
unsigned int size;
|
||||
char mode;
|
||||
};
|
||||
|
||||
/**
|
||||
* struct comedi_isadma - ISA DMA data
|
||||
* @desc: cookie for each DMA buffer
|
||||
* @n_desc: the number of cookies
|
||||
* @cur_dma: the current cookie in use
|
||||
* @chan: the first DMA channel requested
|
||||
* @chan2: the second DMA channel requested
|
||||
*/
|
||||
struct comedi_isadma {
|
||||
struct comedi_isadma_desc *desc;
|
||||
int n_desc;
|
||||
int cur_dma;
|
||||
unsigned int chan;
|
||||
unsigned int chan2;
|
||||
};
|
||||
|
||||
#if IS_ENABLED(CONFIG_ISA_DMA_API)
|
||||
|
||||
void comedi_isadma_program(struct comedi_isadma_desc *);
|
||||
unsigned int comedi_isadma_disable(unsigned int dma_chan);
|
||||
unsigned int comedi_isadma_disable_on_sample(unsigned int dma_chan,
|
||||
unsigned int size);
|
||||
unsigned int comedi_isadma_poll(struct comedi_isadma *);
|
||||
void comedi_isadma_set_mode(struct comedi_isadma_desc *, char dma_dir);
|
||||
|
||||
struct comedi_isadma *comedi_isadma_alloc(struct comedi_device *,
|
||||
int n_desc, unsigned int dma_chan1,
|
||||
unsigned int dma_chan2,
|
||||
unsigned int maxsize, char dma_dir);
|
||||
void comedi_isadma_free(struct comedi_isadma *);
|
||||
|
||||
#else /* !IS_ENABLED(CONFIG_ISA_DMA_API) */
|
||||
|
||||
static inline void comedi_isadma_program(struct comedi_isadma_desc *desc)
|
||||
{
|
||||
}
|
||||
|
||||
static inline unsigned int comedi_isadma_disable(unsigned int dma_chan)
|
||||
{
|
||||
return 0;
|
||||
}
|
||||
|
||||
static inline unsigned int
|
||||
comedi_isadma_disable_on_sample(unsigned int dma_chan, unsigned int size)
|
||||
{
|
||||
return 0;
|
||||
}
|
||||
|
||||
static inline unsigned int comedi_isadma_poll(struct comedi_isadma *dma)
|
||||
{
|
||||
return 0;
|
||||
}
|
||||
|
||||
static inline void comedi_isadma_set_mode(struct comedi_isadma_desc *desc,
|
||||
char dma_dir)
|
||||
{
|
||||
}
|
||||
|
||||
static inline struct comedi_isadma *
|
||||
comedi_isadma_alloc(struct comedi_device *dev, int n_desc,
|
||||
unsigned int dma_chan1, unsigned int dma_chan2,
|
||||
unsigned int maxsize, char dma_dir)
|
||||
{
|
||||
return NULL;
|
||||
}
|
||||
|
||||
static inline void comedi_isadma_free(struct comedi_isadma *dma)
|
||||
{
|
||||
}
|
||||
|
||||
#endif /* !IS_ENABLED(CONFIG_ISA_DMA_API) */
|
||||
|
||||
#endif /* #ifndef _COMEDI_ISADMA_H */
|
||||
Loading…
Reference in New Issue