/*
* linux/arch/arm/mach-imx/dma.c
*
* imx DMA registration and IRQ dispatching
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 2004-03-03 Sascha Hauer <sascha@saschahauer.de>
* initial version heavily inspired by
* linux/arch/arm/mach-pxa/dma.c
*
* 2005-04-17 Pavel Pisa <pisa@cmp.felk.cvut.cz>
* Changed to support scatter gather DMA
* by taking Russell's code from RiscPC
*
* 2006-05-31 Pavel Pisa <pisa@cmp.felk.cvut.cz>
* Corrected error handling code.
*
*/
#undef DEBUG
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <asm/system.h>
#include <asm/irq.h>
#include <asm/hardware.h>
#include <asm/dma.h>
#include <asm/arch/imx-dma.h>
struct imx_dma_channel imx_dma_channels[IMX_DMA_CHANNELS];
/*
* imx_dma_sg_next - prepare next chunk for scatter-gather DMA emulation
* @dma_ch: i.MX DMA channel number
* @lastcount: number of bytes transferred during last transfer
*
* Functions prepares DMA controller for next sg data chunk transfer.
* The @lastcount argument informs function about number of bytes transferred
* during last block. Zero value can be used for @lastcount to setup DMA
* for the first chunk.
*/
static inline int imx_dma_sg_next(imx_dmach_t dma_ch, unsigned int lastcount)
{
struct imx_dma_channel *imxdma = &imx_dma_channels[dma_ch];
unsigned int nextcount;
unsigned int nextaddr;
if (!imxdma->name) {
printk(KERN_CRIT "%s: called for not allocated channel %d\n",
__FUNCTION__, dma_ch);
return 0;
}
imxdma->resbytes -= lastcount;
if (!imxdma->sg) {
pr_debug("imxdma%d: no sg data\n", dma_ch);
return 0;
}
imxdma->sgbc += lastcount;
if ((imxdma->sgbc >= imxdma->sg->length) || !imxdma->resbytes) {
if ((imxdma->sgcount <= 1) || !imxdma->resbytes) {
pr_debug("imxdma%d: sg transfer limit reached\n",
dma_ch);
imxdma->sgcount=0;
imxdma->sg = NULL;
return 0;
} else {
imxdma->sgcount--;
imxdma->sg++;
imxdma->sgbc = 0;
}
}
nextcount = imxdma->sg->length - imxdma->sgbc;
nextaddr = imxdma->sg->dma_address + imxdma->sgbc;
if(imxdma->resbytes < nextcount)
nextcount = imxdma->resbytes;
if ((imxdma->dma_mode & DMA_MODE_MASK) == DMA_MODE_READ)
DAR(dma_ch) = nextaddr;
else
SAR(dma_ch) = nextaddr;
CNTR(dma_ch) = nextcount;
pr_debug("imxdma%d: next sg chunk dst 0x%08x, src 0x%08x, size 0x%08x\n",
dma_ch, DAR(dma_ch), SAR(dma_ch), CNTR(dma_ch));
return nextcount;
}
/*
* imx_dma_setup_sg_base - scatter-gather DMA emulation
* @dma_ch: i.MX DMA channel number
* @sg: pointer to the scatter-gather list/vector
* @sgcount: scatter-gather list hungs count
*
* Functions sets up i.MX DMA state for emulated scatter-gather transfer
* and sets up channel registers to be ready for the first chunk
*/
static int
imx_dma_setup_sg_base(imx_dmach_t dma_ch,
struct scatterlist *sg, unsigned int sgcount)
{
struct imx_dma_channel *imxdma = &imx_dma_channels[dma_ch];
imxdma->sg = sg;
imxdma->sgcount = sgcount;
imxdma->sgbc = 0;
return imx_dma_sg_next(dma_ch, 0);
}
/**
* imx_dma_setup_single - setup i.MX DMA channel for linear memory to/from device transfer
* @dma_ch: i.MX DMA channel number
* @dma_address: the DMA/physical memory address of the linear data block
* to transfer
* @dma_length: length of the data block in bytes
* @dev_addr: physical device port address
* @dmamode: DMA transfer mode, %DMA_MODE_READ from the device to the memory
* or %DMA_MODE_WRITE from memory to the device
*
* The function setups DMA channel source and destination addresses for transfer
* specified by provided parameters. The scatter-gather emulation is disabled,
* because linear data block
* form the physical address range is transfered.
* Return value: if incorrect parameters are provided -%EINVAL.
* Zero indicates success.
*/
int
imx_dma_setup_single(imx_dmach_t dma_ch, dma_addr_t dma_address,
unsigned int dma_length, unsigned int dev_addr,
dmamode_t dmamode)
{
struct imx_dma_channel *imxdma = &imx_dma_channels[dma_ch];
imxdma->sg = NULL;
imxdma->sgcount = 0;
imxdma->dma_mode = dmamode;
imxdma->resbytes = dma_length;
if (!dma_address) {
printk(KERN_ERR "imxdma%d: imx_dma_setup_single null address\n",
dma_ch);
return -EINVAL;
}
if (!dma_length) {
printk(KERN_ERR "imxdma%d: imx_dma_setup_single zero length\n",
dma_ch);
return -EINVAL;
}
if ((dmamode & DMA_MODE_MASK) == DMA_MODE_READ) {
pr_debug("imxdma%d: mx_dma_setup_single2dev dma_addressg=0x%08x dma_length=%d dev_addr=0x%08x for read\n",
dma_ch, (unsigned int)dma_address, dma_length,
dev_addr);
SAR(dma_ch) = dev_addr;
DAR(dma_ch) = (unsigned int)dma_address;
} else if ((dmamode & DMA_MODE_MASK) == DMA_MODE_WRITE) {
pr_debug("imxdma%d: mx_dma_setup_single2dev dma_addressg=0x%08x dma_length=%d dev_addr=0x%08x for write\n",
dma_ch, (unsigned int)dma_address, dma_length,
dev_addr);
SAR(dma_ch) = (unsigned int)dma_address;
DAR(dma_ch) = dev_addr;
} else {
printk(KERN_ERR "imxdma%d: imx_dma_setup_single bad dmamode\n",
dma_ch);
return -EINVAL;
}
CNTR(dma_ch) = dma_length;
return 0;
}
/**
* imx_dma_setup_sg - setup i.MX DMA channel SG list to/from device transfer
* @dma_ch: i.MX DMA channel number
* @sg: pointer to the scatter-gather list/vector
* @sgcount: scatter-gather list hungs count
* @dma_length: total length of the transfer request in bytes
* @dev_addr: physical device port address
* @dmamode: DMA transfer mode, %DMA_MODE_READ from the device to the memory
* or %DMA_MODE_WRITE from memory to the device
*
* The function setups DMA channel state and registers to be ready for transfer
* specified by provided parameters. The scatter-gather emulation is set up
* according to the parameters.
*
* The full preparation of the transfer requires setup of more register
* by the caller before imx_dma_enable() can be called.
*
* %BLR(dma_ch) holds transfer burst length in bytes, 0 means 64 bytes
*
* %RSSR(dma_ch) has to be set to the DMA request line source %DMA_REQ_xxx
*
* %CCR(dma_ch) has to specify transfer parameters, the next settings is typical
* for linear or simple scatter-gather transfers if %DMA_MODE_READ is specified
*
* %CCR_DMOD_LINEAR | %CCR_DSIZ_32 | %CCR_SMOD_FIFO | %CCR_SSIZ_x
*
* The typical setup for %DMA_MODE_WRITE is specified by next options combination
*
* %CCR_SMOD_LINEAR | %CCR_SSIZ_32 | %CCR_DMOD_FIFO | %CCR_DSIZ_x
*
* Be carefull there and do not mistakenly mix source and target device
* port sizes constants, they are really different:
* %CCR_SSIZ_8, %CCR_SSIZ_16, %CCR_SSIZ_32,
* %CCR_DSIZ_8, %CCR_DSIZ_16, %CCR_DSIZ_32
*
* Return value: if incorrect parameters are provided -%EINVAL.
* Zero indicates success.
*/
int
imx_dma_setup_sg(imx_dmach_t dma_ch,
struct scatterlist *sg, unsigned int sgcount, unsigned int dma_length,
unsigned int dev_addr, dmamode_t dmamode)
{
int res;
struct imx_dma_channel *imxdma = &imx_dma_channels[dma_ch];
imxdma->sg = NULL;
imxdma->sgcount = 0;
imxdma->dma_mode = dmamode;
imxdma->resbytes = dma_length;
if (!sg || !sgcount) {
printk(KERN_ERR "imxdma%d: imx_dma_setup_sg epty sg list\n",
dma_ch);
return -EINVAL;
}
if (!sg->length) {
printk(KERN_ERR "imxdma%d: imx_dma_setup_sg zero length\n",
dma_ch);
return -EINVAL;
}
if ((dmamode & DMA_MODE_MASK) == DMA_MODE_READ) {
pr_debug("imxdma%d: mx_dma_setup_sg2dev sg=%p sgcount=%d total length=%d dev_addr=0x%08x for read\n",
dma_ch, sg, sgcount, dma_length, dev_addr);
SAR(dma_ch) = dev_addr;
} else if ((dmamode & DMA_MODE_MASK) == DMA_MODE_WRITE) {
pr_debug("imxdma%d: mx_dma_setup_sg2dev sg=%p sgcount=%d total length=%d dev_addr=0x%08x for write\n",
dma_ch, sg, sgcount, dma_length, dev_addr);
DAR(dma_ch) = dev_addr;
} else {
printk(KERN_ERR "imxdma%d: imx_dma_setup_sg bad dmamode\n",
dma_ch);
return -EINVAL;
}
res = imx_dma_setup_sg_base(dma_ch, sg, sgcount);
if (res <= 0) {
printk(KERN_ERR "imxdma%d: no sg chunk ready\n", dma_ch);
return -EINVAL;
}
return 0;
}
/**
* imx_dma_setup_handlers - setup i.MX DMA channel end and error notification handlers
* @dma_ch: i.MX DMA channel number
* @irq_handler: the pointer to the function called if the transfer
* ends successfully
* @err_handler: the pointer to the function called if the premature
* end caused by error occurs
* @data: user specified value to be passed to the handlers
*/
int
imx_dma_setup_handlers(imx_dmach_t dma_ch,
void (*irq_handler) (int, void *),
void (*err_handler) (int, void *, int),
void *data)
{
struct imx_dma_channel *imxdma = &imx_dma_channels[dma_ch];
unsigned long flags;
if (!imxdma->name) {
printk(KERN_CRIT "%s: called for not allocated channel %d\n",
__FUNCTION__, dma_ch);
return -ENODEV;
}
local_irq_save(flags);
DISR = (1 << dma_ch);
imxdma->irq_handler = irq_handler;
imxdma->err_handler = err_handler;
imxdma->data = data;
local_irq_restore(flags);
return 0;
}
/**
* imx_dma_enable - function to start i.MX DMA channel operation
* @dma_ch: i.MX DMA channel number
*
* The channel has to be allocated by driver through imx_dma_request()
* or imx_dma_request_by_prio() function.
* The transfer parameters has to be set to the channel registers through
* call of the imx_dma_setup_single() or imx_dma_setup_sg() function
* and registers %BLR(dma_ch), %RSSR(dma_ch) and %CCR(dma_ch) has to
* be set prior this function call by the channel user.
*/
void imx_dma_enable(imx_dmach_t dma_ch)
{
struct imx_dma_channel *imxdma = &imx_dma_channels[dma_ch];
unsigned long flags;
pr_debug("imxdma%d: imx_dma_enable\n", dma_ch);
if (!imxdma->name) {
printk(KERN_CRIT "%s: called for not allocated channel %d\n",
__FUNCTION__, dma_ch);
return;
}
local_irq_save(flags);
DISR = (1 << dma_ch);
DIMR &= ~(1 << dma_ch);
CCR(dma_ch) |= CCR_CEN;
local_irq_restore(flags);
}
/**
* imx_dma_disable - stop, finish i.MX DMA channel operatin
* @dma_ch: i.MX DMA channel number
*/
void imx_dma_disable(imx_dmach_t dma_ch)
{
unsigned long flags;
pr_debug("imxdma%d: imx_dma_disable\n", dma_ch);
local_irq_save(flags);
DIMR |= (1 << dma_ch);
CCR(dma_ch) &= ~CCR_CEN;
DISR = (1 << dma_ch);
local_irq_restore(flags);
}
/**
* imx_dma_request - request/allocate specified channel number
* @dma_ch: i.MX DMA channel number
* @name: the driver/caller own non-%NULL identification
*/
int imx_dma_request(imx_dmach_t dma_ch, const char *name)
{
struct imx_dma_channel *imxdma = &imx_dma_channels[dma_ch];
unsigned long flags;
/* basic sanity checks */
if (!name)
return -EINVAL;
if (dma_ch >= IMX_DMA_CHANNELS) {
printk(KERN_CRIT "%s: called for non-existed channel %d\n",
__FUNCTION__, dma_ch);
return -EINVAL;
}
local_irq_save(flags);
if (imxdma->name) {
local_irq_restore(flags);
return -ENODEV;
}
imxdma->name = name;
imxdma->irq_handler = NULL;
imxdma->err_handler = NULL;
imxdma->data = NULL;
imxdma->sg = NULL;
local_irq_restore(flags);
return 0;
}
/**
* imx_dma_free - release previously acquired channel
* @dma_ch: i.MX DMA channel number
*/
void imx_dma_free(imx_dmach_t dma_ch)
{
unsigned long flags;
struct imx_dma_channel *imxdma = &imx_dma_channels[dma_ch];
if (!imxdma->name) {
printk(KERN_CRIT
"%s: trying to free channel %d which is already freed\n",
__FUNCTION__, dma_ch);
return;
}
local_irq_save(flags);
/* Disable interrupts */
DIMR |= (1 << dma_ch);
CCR(dma_ch) &= ~CCR_CEN;
imxdma->name = NULL;
local_irq_restore(flags);
}
/**
* imx_dma_request_by_prio - find and request some of free channels best suiting requested priority
* @dma_ch: i.MX DMA channel number
* @name: the driver/caller own non-%NULL identification
* @prio: one of the hardware distinguished priority level:
* %DMA_PRIO_HIGH, %DMA_PRIO_MEDIUM, %DMA_PRIO_LOW
*
* This function tries to find free channel in the specified priority group
* if the priority cannot be achieved it tries to look for free channel
* in the higher and then even lower priority groups.
*
* Return value: If there is no free channel to allocate, -%ENODEV is returned.
* Zero value indicates successful channel allocation.
*/
int
imx_dma_request_by_prio(imx_dmach_t * pdma_ch, const char *name,
imx_dma_prio prio)
{
int i;
int best;
switch (prio) {
case (DMA_PRIO_HIGH):
best = 8;
break;
case (DMA_PRIO_MEDIUM):
best = 4;
break;
case (DMA_PRIO_LOW):
default:
best = 0;
break;
}
for (i = best; i < IMX_DMA_CHANNELS; i++) {
if (!imx_dma_request(i, name)) {
*pdma_ch = i;
return 0;
}
}
for (i = best - 1; i >= 0; i--) {
if (!imx_dma_request(i, name)) {
*pdma_ch = i;
return 0;
}
}
printk(KERN_ERR "%s: no free DMA channel found\n", __FUNCTION__);
return -ENODEV;
}
static irqreturn_t dma_err_handler(int irq, void *dev_id)
{
int i, disr = DISR;
struct imx_dma_channel *channel;
unsigned int err_mask = DBTOSR | DRTOSR | DSESR | DBOSR;
int errcode;
DISR = disr & err_mask;
for (i = 0; i < IMX_DMA_CHANNELS; i++) {
if(!(err_mask & (1 << i)))
continue;
channel = &imx_dma_channels[i];
errcode = 0;
if (DBTOSR & (1 << i)) {
DBTOSR = (1 << i);
errcode |= IMX_DMA_ERR_BURST;
}
if (DRTOSR & (1 << i)) {
DRTOSR = (1 << i);
errcode |= IMX_DMA_ERR_REQUEST;
}
if (DSESR & (1 << i)) {
DSESR = (1 << i);
errcode |= IMX_DMA_ERR_TRANSFER;
}
if (DBOSR & (1 << i)) {
DBOSR = (1 << i);
errcode |= IMX_DMA_ERR_BUFFER;
}
/*
* The cleaning of @sg field would be questionable
* there, because its value can help to compute
* remaining/transfered bytes count in the handler
*/
/*imx_dma_channels[i].sg = NULL;*/
if (channel->name && channel->err_handler) {
channel->err_handler(i, channel->data, errcode);
continue;
}
imx_dma_channels[i].sg = NULL;
printk(KERN_WARNING
"DMA timeout on channel %d (%s) -%s%s%s%s\n",
i, channel->name,
errcode&IMX_DMA_ERR_BURST? " burst":"",
errcode&IMX_DMA_ERR_REQUEST? " request":"",
errcode&IMX_DMA_ERR_TRANSFER? " transfer":"",
errcode&IMX_DMA_ERR_BUFFER? " buffer":"");
}
return IRQ_HANDLED;
}
static irqreturn_t dma_irq_handler(int irq, void *dev_id)
{
int i, disr = DISR;
pr_debug("imxdma: dma_irq_handler called, disr=0x%08x\n",
disr);
DISR = disr;
for (i = 0; i < IMX_DMA_CHANNELS; i++) {
if (disr & (1 << i)) {
struct imx_dma_channel *channel = &imx_dma_channels[i];
if (channel->name) {
if (imx_dma_sg_next(i, CNTR(i))) {
CCR(i) &= ~CCR_CEN;
mb();
CCR(i) |= CCR_CEN;
} else {
if (channel->irq_handler)
channel->irq_handler(i,
channel->data);
}
} else {
/*
* IRQ for an unregistered DMA channel:
* let's clear the interrupts and disable it.
*/
printk(KERN_WARNING
"spurious IRQ for DMA channel %d\n", i);
}
}
}
return IRQ_HANDLED;
}
static int __init imx_dma_init(void)
{
int ret;
int i;
/* reset DMA module */
DCR = DCR_DRST;
ret = request_irq(DMA_INT, dma_irq_handler, 0, "DMA", NULL);
if (ret) {
printk(KERN_CRIT "Wow! Can't register IRQ for DMA\n");
return ret;
}
ret = request_irq(DMA_ERR, dma_err_handler, 0, "DMA", NULL);
if (ret) {
printk(KERN_CRIT "Wow! Can't register ERRIRQ for DMA\n");
free_irq(DMA_INT, NULL);
}
/* enable DMA module */
DCR = DCR_DEN;
/* clear all interrupts */
DISR = (1 << IMX_DMA_CHANNELS) - 1;
/* enable interrupts */
DIMR = (1 << IMX_DMA_CHANNELS) - 1;
for (i = 0; i < IMX_DMA_CHANNELS; i++) {
imx_dma_channels[i].sg = NULL;
imx_dma_channels[i].dma_num = i;
}
return ret;
}
arch_initcall(imx_dma_init);
EXPORT_SYMBOL(imx_dma_setup_single);
EXPORT_SYMBOL(imx_dma_setup_sg);
EXPORT_SYMBOL(imx_dma_setup_handlers);
EXPORT_SYMBOL(imx_dma_enable);
EXPORT_SYMBOL(imx_dma_disable);
EXPORT_SYMBOL(imx_dma_request);
EXPORT_SYMBOL(imx_dma_free);
EXPORT_SYMBOL(imx_dma_request_by_prio);
EXPORT_SYMBOL(imx_dma_channels);
