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ALSA: firewire-lib: allocate DMA buffer separately 

For correct cache coherency on some architectures, DMA buffers must be
allocated in a different cache line than data that is concurrently used
by the CPU.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Clemens Ladisch 2011-03-15 07:55:50 +01:00 committed by Takashi Iwai
parent be45436632
commit 5b2599a07e
3 changed files with 16 additions and 5 deletions
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5
sound/firewire/cmp.c
View File

@ -117,9 +117,12 @@ int cmp_connection_init(struct cmp_connection *c,
if (ipcr_index >= (impr & IMPR_PLUGS_MASK))
return -EINVAL;
err = fw_iso_resources_init(&c->resources, unit);
if (err < 0)
return err;
c->connected = false;
mutex_init(&c->mutex);
fw_iso_resources_init(&c->resources, unit);
c->last_pcr_value = cpu_to_be32(0x80000000);
c->pcr_index = ipcr_index;
c->max_speed = (impr & IMPR_SPEED_MASK) >> IMPR_SPEED_SHIFT;

10
sound/firewire/iso-resources.c
View File

@ -11,6 +11,7 @@
#include <linux/jiffies.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include "iso-resources.h"
@ -22,12 +23,18 @@
* If the device does not support all channel numbers, change @r->channels_mask
* after calling this function.
*/
void fw_iso_resources_init(struct fw_iso_resources *r, struct fw_unit *unit)
int fw_iso_resources_init(struct fw_iso_resources *r, struct fw_unit *unit)
{
r->buffer = kmalloc(2 * 4, GFP_KERNEL);
if (!r->buffer)
return -ENOMEM;
r->channels_mask = ~0uLL;
r->unit = fw_unit_get(unit);
mutex_init(&r->mutex);
r->allocated = false;
return 0;
}
/**
@ -37,6 +44,7 @@ void fw_iso_resources_init(struct fw_iso_resources *r, struct fw_unit *unit)
void fw_iso_resources_destroy(struct fw_iso_resources *r)
{
WARN_ON(r->allocated);
kfree(r->buffer);
mutex_destroy(&r->mutex);
fw_unit_put(r->unit);
}

6
sound/firewire/iso-resources.h
View File

@ -24,11 +24,11 @@ struct fw_iso_resources {
unsigned int bandwidth_overhead;
int generation; /* in which allocation is valid */
bool allocated;
__be32 buffer[2];
__be32 *buffer;
};
void fw_iso_resources_init(struct fw_iso_resources *r,
struct fw_unit *unit);
int fw_iso_resources_init(struct fw_iso_resources *r,
struct fw_unit *unit);
void fw_iso_resources_destroy(struct fw_iso_resources *r);
int fw_iso_resources_allocate(struct fw_iso_resources *r,