/*
* DMA helper routines for Freescale STMP37XX/STMP378X
*
* Author: dmitry pervushin <dpervushin@embeddedalley.com>
*
* Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved.
* Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
*/
/*
* The code contained herein is licensed under the GNU General Public
* License. You may obtain a copy of the GNU General Public License
* Version 2 or later at the following locations:
*
* http://www.opensource.org/licenses/gpl-license.html
* http://www.gnu.org/copyleft/gpl.html
*/
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/dmapool.h>
#include <linux/sysdev.h>
#include <linux/cpufreq.h>
#include <asm/page.h>
#include <mach/dma.h>
#include <mach/regs-apbx.h>
#include <mach/regs-apbh.h>
static const size_t pool_item_size = sizeof(struct stmp3xxx_dma_command);
static const size_t pool_alignment = 8;
static struct stmp3xxx_dma_user {
void *pool;
int inuse;
const char *name;
} channels[MAX_DMA_CHANNELS];
static inline int dmach(int ch)
{
return ch % 16;
}
static inline int dmabus(int ch)
{
return ch / 16;
}
#define IS_VALID_CHANNEL(ch) ((ch) >= 0 && (ch) < MAX_DMA_CHANNELS)
#define IS_USED(ch) (channels[ch].inuse)
int stmp3xxx_dma_request(int ch, struct device *dev, const char *name)
{
struct stmp3xxx_dma_user *user;
int err = 0;
user = channels + ch;
if (!IS_VALID_CHANNEL(ch)) {
err = -ENODEV;
goto out;
}
if (IS_USED(ch)) {
err = -EBUSY;
goto out;
}
/* Create a pool to allocate dma commands from */
user->pool = dma_pool_create(name, dev, pool_item_size,
pool_alignment, PAGE_SIZE);
if (user->pool == NULL) {
err = -ENOMEM;
goto out;
}
user->name = name;
user->inuse++;
out:
return err;
}
EXPORT_SYMBOL(stmp3xxx_dma_request);
int stmp3xxx_dma_release(int ch)
{
struct stmp3xxx_dma_user *user = channels + ch;
int err = 0;
if (!IS_VALID_CHANNEL(ch)) {
err = -ENODEV;
goto out;
}
if (!IS_USED(ch)) {
err = -EBUSY;
goto out;
}
BUG_ON(user->pool == NULL);
dma_pool_destroy(user->pool);
user->inuse--;
out:
return err;
}
EXPORT_SYMBOL(stmp3xxx_dma_release);
int stmp3xxx_dma_read_semaphore(int channel)
{
int sem = -1;
switch (dmabus(channel)) {
case STMP3XXX_BUS_APBH:
sem =
(HW_APBH_CHn_SEMA_RD(dmach(channel)) &
BM_APBH_CHn_SEMA_PHORE) >> BP_APBH_CHn_SEMA_PHORE;
break;
case STMP3XXX_BUS_APBX:
sem =
(HW_APBX_CHn_SEMA_RD(dmach(channel)) &
BM_APBX_CHn_SEMA_PHORE) >> BP_APBX_CHn_SEMA_PHORE;
break;
default:
BUG();
}
return sem;
}
EXPORT_SYMBOL(stmp3xxx_dma_read_semaphore);
int stmp3xxx_dma_allocate_command(int channel,
struct stmp3xxx_dma_descriptor *descriptor)
{
struct stmp3xxx_dma_user *user = channels + channel;
int err = 0;
if (!IS_VALID_CHANNEL(channel)) {
err = -ENODEV;
goto out;
}
if (!IS_USED(channel)) {
err = -EBUSY;
goto out;
}
if (descriptor == NULL) {
err = -EINVAL;
goto out;
}
/* Allocate memory for a command from the buffer */
descriptor->command =
dma_pool_alloc(user->pool, GFP_KERNEL, &descriptor->handle);
/* Check it worked */
if (!descriptor->command) {
err = -ENOMEM;
goto out;
}
memset(descriptor->command, 0, pool_item_size);
out:
WARN_ON(err);
return err;
}
EXPORT_SYMBOL(stmp3xxx_dma_allocate_command);
int stmp3xxx_dma_free_command(int channel,
struct stmp3xxx_dma_descriptor *descriptor)
{
int err = 0;
if (!IS_VALID_CHANNEL(channel)) {
err = -ENODEV;
goto out;
}
if (!IS_USED(channel)) {
err = -EBUSY;
goto out;
}
/* Return the command memory to the pool */
dma_pool_free(channels[channel].pool, descriptor->command,
descriptor->handle);
/* Initialise descriptor so we're not tempted to use it */
descriptor->command = NULL;
descriptor->handle = 0;
descriptor->virtual_buf_ptr = NULL;
descriptor->next_descr = NULL;
WARN_ON(err);
out:
return err;
}
EXPORT_SYMBOL(stmp3xxx_dma_free_command);
void stmp3xxx_dma_go(int channel,
struct stmp3xxx_dma_descriptor *head, u32 semaphore)
{
int ch = dmach(channel);
switch (dmabus(channel)) {
case STMP3XXX_BUS_APBH:
/* Set next command */
HW_APBH_CHn_NXTCMDAR_WR(ch, head->handle);
/* Set counting semaphore (kicks off transfer). Assumes
peripheral has been set up correctly */
HW_APBH_CHn_SEMA_WR(ch, semaphore);
break;
case STMP3XXX_BUS_APBX:
/* Set next command */
HW_APBX_CHn_NXTCMDAR_WR(ch, head->handle);
/* Set counting semaphore (kicks off transfer). Assumes
peripheral has been set up correctly */
HW_APBX_CHn_SEMA_WR(ch, semaphore);
break;
}
}
EXPORT_SYMBOL(stmp3xxx_dma_go);
int stmp3xxx_dma_running(int channel)
{
switch (dmabus(channel)) {
case STMP3XXX_BUS_APBH:
return HW_APBH_CHn_SEMA_RD(dmach(channel)) &
BM_APBH_CHn_SEMA_PHORE;
case STMP3XXX_BUS_APBX:
return HW_APBX_CHn_SEMA_RD(dmach(channel)) &
BM_APBX_CHn_SEMA_PHORE;
default:
BUG();
return 0;
}
}
EXPORT_SYMBOL(stmp3xxx_dma_running);
/*
* Circular dma chain management
*/
void stmp3xxx_dma_free_chain(struct stmp37xx_circ_dma_chain *chain)
{
int i;
for (i = 0; i < chain->total_count; i++)
stmp3xxx_dma_free_command(
STMP3xxx_DMA(chain->channel, chain->bus),
&chain->chain[i]);
}
EXPORT_SYMBOL(stmp3xxx_dma_free_chain);
int stmp3xxx_dma_make_chain(int ch, struct stmp37xx_circ_dma_chain *chain,
struct stmp3xxx_dma_descriptor descriptors[],
unsigned items)
{
int i;
int err = 0;
if (items == 0)
return err;
for (i = 0; i < items; i++) {
err = stmp3xxx_dma_allocate_command(ch, &descriptors[i]);
if (err) {
WARN_ON(err);
/*
* Couldn't allocate the whole chain.
* deallocate what has been allocated
*/
if (i) {
do {
stmp3xxx_dma_free_command(ch,
&descriptors
[i]);
} while (i-- >= 0);
}
return err;
}
/* link them! */
if (i > 0) {
descriptors[i - 1].next_descr = &descriptors[i];
descriptors[i - 1].command->next =
descriptors[i].handle;
}
}
/* make list circular */
descriptors[items - 1].next_descr = &descriptors[0];
descriptors[items - 1].command->next = descriptors[0].handle;
chain->total_count = items;
chain->chain = descriptors;
chain->free_index = 0;
chain->active_index = 0;
chain->cooked_index = 0;
chain->free_count = items;
chain->active_count = 0;
chain->cooked_count = 0;
chain->bus = dmabus(ch);
chain->channel = dmach(ch);
return err;
}
EXPORT_SYMBOL(stmp3xxx_dma_make_chain);
void stmp37xx_circ_clear_chain(struct stmp37xx_circ_dma_chain *chain)
{
BUG_ON(stmp3xxx_dma_running(STMP3xxx_DMA(chain->channel, chain->bus)) >
0);
chain->free_index = 0;
chain->active_index = 0;
chain->cooked_index = 0;
chain->free_count = chain->total_count;
chain->active_count = 0;
chain->cooked_count = 0;
}
EXPORT_SYMBOL(stmp37xx_circ_clear_chain);
void stmp37xx_circ_advance_free(struct stmp37xx_circ_dma_chain *chain,
unsigned count)
{
BUG_ON(chain->cooked_count < count);
chain->cooked_count -= count;
chain->cooked_index += count;
chain->cooked_index %= chain->total_count;
chain->free_count += count;
}
EXPORT_SYMBOL(stmp37xx_circ_advance_free);
void stmp37xx_circ_advance_active(struct stmp37xx_circ_dma_chain *chain,
unsigned count)
{
BUG_ON(chain->free_count < count);
chain->free_count -= count;
chain->free_index += count;
chain->free_index %= chain->total_count;
chain->active_count += count;
switch (chain->bus) {
case STMP3XXX_BUS_APBH:
/* Set counting semaphore (kicks off transfer). Assumes
peripheral has been set up correctly */
HW_APBH_CHn_SEMA_CLR(chain->channel,
BM_APBH_CHn_SEMA_INCREMENT_SEMA);
HW_APBH_CHn_SEMA_SET(chain->channel,
BF_APBH_CHn_SEMA_INCREMENT_SEMA(count));
break;
case STMP3XXX_BUS_APBX:
/* Set counting semaphore (kicks off transfer). Assumes
peripheral has been set up correctly */
HW_APBX_CHn_SEMA_CLR(chain->channel,
BM_APBX_CHn_SEMA_INCREMENT_SEMA);
HW_APBX_CHn_SEMA_SET(chain->channel,
BF_APBX_CHn_SEMA_INCREMENT_SEMA(count));
break;
default:
BUG();
}
}
EXPORT_SYMBOL(stmp37xx_circ_advance_active);
unsigned stmp37xx_circ_advance_cooked(struct stmp37xx_circ_dma_chain *chain)
{
unsigned cooked;
cooked = chain->active_count -
stmp3xxx_dma_read_semaphore(STMP3xxx_DMA(chain->channel, chain->bus));
chain->active_count -= cooked;
chain->active_index += cooked;
chain->active_index %= chain->total_count;
chain->cooked_count += cooked;
return cooked;
}
EXPORT_SYMBOL(stmp37xx_circ_advance_cooked);
void stmp3xxx_dma_set_alt_target(int channel, int function)
{
#if defined(CONFIG_ARCH_STMP37XX)
unsigned bits = 4;
#elif defined(CONFIG_ARCH_STMP378X)
unsigned bits = 2;
#else
#error wrong arch
#endif
int shift = dmach(channel) * bits;
unsigned mask = (1<<bits) - 1;
BUG_ON(function < 0 || function >= (1<<bits));
pr_debug("%s: channel = %d, using mask %x, "
"shift = %d\n", __func__, channel, mask, shift);
switch (dmabus(channel)) {
case STMP3XXX_BUS_APBH:
HW_APBH_DEVSEL_CLR(mask<<shift);
HW_APBH_DEVSEL_SET(function<<shift);
break;
case STMP3XXX_BUS_APBX:
HW_APBX_DEVSEL_CLR(mask<<shift);
HW_APBX_DEVSEL_SET(function<<shift);
break;
default:
BUG();
}
}
EXPORT_SYMBOL(stmp3xxx_dma_set_alt_target);
void stmp3xxx_dma_suspend(void)
{
HW_APBH_CTRL0_SET(BM_APBH_CTRL0_CLKGATE);
HW_APBX_CTRL0_SET(BM_APBX_CTRL0_CLKGATE);
}
void stmp3xxx_dma_resume(void)
{
HW_APBH_CTRL0_CLR(BM_APBH_CTRL0_CLKGATE | BM_APBH_CTRL0_SFTRST);
HW_APBX_CTRL0_CLR(BM_APBX_CTRL0_CLKGATE | BM_APBX_CTRL0_SFTRST);
}
#ifdef CONFIG_CPU_FREQ
struct dma_notifier_block {
struct notifier_block nb;
void *data;
};
static int dma_cpufreq_notifier(struct notifier_block *self,
unsigned long phase, void *p)
{
switch (phase) {
case CPUFREQ_POSTCHANGE:
stmp3xxx_dma_resume();
break;
case CPUFREQ_PRECHANGE:
stmp3xxx_dma_suspend();
break;
default:
break;
}
return NOTIFY_DONE;
}
static struct dma_notifier_block dma_cpufreq_nb = {
.nb = {
.notifier_call = dma_cpufreq_notifier,
},
};
#endif /* CONFIG_CPU_FREQ */
void __init stmp3xxx_dma_init(void)
{
HW_APBH_CTRL0_CLR(BM_APBH_CTRL0_CLKGATE | BM_APBH_CTRL0_SFTRST);
HW_APBX_CTRL0_CLR(BM_APBX_CTRL0_CLKGATE | BM_APBX_CTRL0_SFTRST);
#ifdef CONFIG_CPU_FREQ
cpufreq_register_notifier(&dma_cpufreq_nb.nb,
CPUFREQ_TRANSITION_NOTIFIER);
#endif /* CONFIG_CPU_FREQ */
}
