linux/drivers/media/dvb/firewire/firedtv-fw.c
Clemens Ladisch 13882a82ee firewire: optimize iso queueing by setting wake only after the last packet
When queueing iso packets, the run time is dominated by the two
MMIO accesses that set the DMA context's wake bit.  Because most
drivers submit packets in batches, we can save much time by
removing all but the last wakeup.

The internal kernel API is changed to require a call to
fw_iso_context_queue_flush() after a batch of queued packets.
The user space API does not change, so one call to
FW_CDEV_IOC_QUEUE_ISO must specify multiple packets to take
advantage of this optimization.

In my measurements, this patch reduces the time needed to queue
fifty skip packets from userspace to one sixth on a 2.5 GHz CPU,
or to one third at 800 MHz.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2011-05-10 22:53:45 +02:00

431 lines
10 KiB
C

/*
* FireDTV driver -- firewire I/O backend
*/
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/firewire.h>
#include <linux/firewire-constants.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/wait.h>
#include <linux/workqueue.h>
#include <asm/page.h>
#include <asm/system.h>
#include <dvb_demux.h>
#include "firedtv.h"
static LIST_HEAD(node_list);
static DEFINE_SPINLOCK(node_list_lock);
static inline struct fw_device *device_of(struct firedtv *fdtv)
{
return fw_device(fdtv->device->parent);
}
static int node_req(struct firedtv *fdtv, u64 addr, void *data, size_t len,
int tcode)
{
struct fw_device *device = device_of(fdtv);
int rcode, generation = device->generation;
smp_rmb(); /* node_id vs. generation */
rcode = fw_run_transaction(device->card, tcode, device->node_id,
generation, device->max_speed, addr, data, len);
return rcode != RCODE_COMPLETE ? -EIO : 0;
}
int fdtv_lock(struct firedtv *fdtv, u64 addr, void *data)
{
return node_req(fdtv, addr, data, 8, TCODE_LOCK_COMPARE_SWAP);
}
int fdtv_read(struct firedtv *fdtv, u64 addr, void *data)
{
return node_req(fdtv, addr, data, 4, TCODE_READ_QUADLET_REQUEST);
}
int fdtv_write(struct firedtv *fdtv, u64 addr, void *data, size_t len)
{
return node_req(fdtv, addr, data, len, TCODE_WRITE_BLOCK_REQUEST);
}
#define ISO_HEADER_SIZE 4
#define CIP_HEADER_SIZE 8
#define MPEG2_TS_HEADER_SIZE 4
#define MPEG2_TS_SOURCE_PACKET_SIZE (4 + 188)
#define MAX_PACKET_SIZE 1024 /* 776, rounded up to 2^n */
#define PACKETS_PER_PAGE (PAGE_SIZE / MAX_PACKET_SIZE)
#define N_PACKETS 64 /* buffer size */
#define N_PAGES DIV_ROUND_UP(N_PACKETS, PACKETS_PER_PAGE)
#define IRQ_INTERVAL 16
struct fdtv_ir_context {
struct fw_iso_context *context;
struct fw_iso_buffer buffer;
int interrupt_packet;
int current_packet;
char *pages[N_PAGES];
};
static int queue_iso(struct fdtv_ir_context *ctx, int index)
{
struct fw_iso_packet p;
p.payload_length = MAX_PACKET_SIZE;
p.interrupt = !(++ctx->interrupt_packet & (IRQ_INTERVAL - 1));
p.skip = 0;
p.header_length = ISO_HEADER_SIZE;
return fw_iso_context_queue(ctx->context, &p, &ctx->buffer,
index * MAX_PACKET_SIZE);
}
static void handle_iso(struct fw_iso_context *context, u32 cycle,
size_t header_length, void *header, void *data)
{
struct firedtv *fdtv = data;
struct fdtv_ir_context *ctx = fdtv->ir_context;
__be32 *h, *h_end;
int length, err, i = ctx->current_packet;
char *p, *p_end;
for (h = header, h_end = h + header_length / 4; h < h_end; h++) {
length = be32_to_cpup(h) >> 16;
if (unlikely(length > MAX_PACKET_SIZE)) {
dev_err(fdtv->device, "length = %d\n", length);
length = MAX_PACKET_SIZE;
}
p = ctx->pages[i / PACKETS_PER_PAGE]
+ (i % PACKETS_PER_PAGE) * MAX_PACKET_SIZE;
p_end = p + length;
for (p += CIP_HEADER_SIZE + MPEG2_TS_HEADER_SIZE; p < p_end;
p += MPEG2_TS_SOURCE_PACKET_SIZE)
dvb_dmx_swfilter_packets(&fdtv->demux, p, 1);
err = queue_iso(ctx, i);
if (unlikely(err))
dev_err(fdtv->device, "requeue failed\n");
i = (i + 1) & (N_PACKETS - 1);
}
fw_iso_context_queue_flush(ctx->context);
ctx->current_packet = i;
}
int fdtv_start_iso(struct firedtv *fdtv)
{
struct fdtv_ir_context *ctx;
struct fw_device *device = device_of(fdtv);
int i, err;
ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->context = fw_iso_context_create(device->card,
FW_ISO_CONTEXT_RECEIVE, fdtv->isochannel,
device->max_speed, ISO_HEADER_SIZE, handle_iso, fdtv);
if (IS_ERR(ctx->context)) {
err = PTR_ERR(ctx->context);
goto fail_free;
}
err = fw_iso_buffer_init(&ctx->buffer, device->card,
N_PAGES, DMA_FROM_DEVICE);
if (err)
goto fail_context_destroy;
ctx->interrupt_packet = 0;
ctx->current_packet = 0;
for (i = 0; i < N_PAGES; i++)
ctx->pages[i] = page_address(ctx->buffer.pages[i]);
for (i = 0; i < N_PACKETS; i++) {
err = queue_iso(ctx, i);
if (err)
goto fail;
}
err = fw_iso_context_start(ctx->context, -1, 0,
FW_ISO_CONTEXT_MATCH_ALL_TAGS);
if (err)
goto fail;
fdtv->ir_context = ctx;
return 0;
fail:
fw_iso_buffer_destroy(&ctx->buffer, device->card);
fail_context_destroy:
fw_iso_context_destroy(ctx->context);
fail_free:
kfree(ctx);
return err;
}
void fdtv_stop_iso(struct firedtv *fdtv)
{
struct fdtv_ir_context *ctx = fdtv->ir_context;
fw_iso_context_stop(ctx->context);
fw_iso_buffer_destroy(&ctx->buffer, device_of(fdtv)->card);
fw_iso_context_destroy(ctx->context);
kfree(ctx);
}
static void handle_fcp(struct fw_card *card, struct fw_request *request,
int tcode, int destination, int source, int generation,
unsigned long long offset, void *payload, size_t length,
void *callback_data)
{
struct firedtv *f, *fdtv = NULL;
struct fw_device *device;
unsigned long flags;
int su;
if (length < 2 || (((u8 *)payload)[0] & 0xf0) != 0)
return;
su = ((u8 *)payload)[1] & 0x7;
spin_lock_irqsave(&node_list_lock, flags);
list_for_each_entry(f, &node_list, list) {
device = device_of(f);
if (device->generation != generation)
continue;
smp_rmb(); /* node_id vs. generation */
if (device->card == card &&
device->node_id == source &&
(f->subunit == su || (f->subunit == 0 && su == 0x7))) {
fdtv = f;
break;
}
}
spin_unlock_irqrestore(&node_list_lock, flags);
if (fdtv)
avc_recv(fdtv, payload, length);
}
static struct fw_address_handler fcp_handler = {
.length = CSR_FCP_END - CSR_FCP_RESPONSE,
.address_callback = handle_fcp,
};
static const struct fw_address_region fcp_region = {
.start = CSR_REGISTER_BASE + CSR_FCP_RESPONSE,
.end = CSR_REGISTER_BASE + CSR_FCP_END,
};
static const char * const model_names[] = {
[FIREDTV_UNKNOWN] = "unknown type",
[FIREDTV_DVB_S] = "FireDTV S/CI",
[FIREDTV_DVB_C] = "FireDTV C/CI",
[FIREDTV_DVB_T] = "FireDTV T/CI",
[FIREDTV_DVB_S2] = "FireDTV S2 ",
};
/* Adjust the template string if models with longer names appear. */
#define MAX_MODEL_NAME_LEN sizeof("FireDTV ????")
static int node_probe(struct device *dev)
{
struct firedtv *fdtv;
char name[MAX_MODEL_NAME_LEN];
int name_len, i, err;
fdtv = kzalloc(sizeof(*fdtv), GFP_KERNEL);
if (!fdtv)
return -ENOMEM;
dev_set_drvdata(dev, fdtv);
fdtv->device = dev;
fdtv->isochannel = -1;
fdtv->voltage = 0xff;
fdtv->tone = 0xff;
mutex_init(&fdtv->avc_mutex);
init_waitqueue_head(&fdtv->avc_wait);
mutex_init(&fdtv->demux_mutex);
INIT_WORK(&fdtv->remote_ctrl_work, avc_remote_ctrl_work);
name_len = fw_csr_string(fw_unit(dev)->directory, CSR_MODEL,
name, sizeof(name));
for (i = ARRAY_SIZE(model_names); --i; )
if (strlen(model_names[i]) <= name_len &&
strncmp(name, model_names[i], name_len) == 0)
break;
fdtv->type = i;
err = fdtv_register_rc(fdtv, dev);
if (err)
goto fail_free;
spin_lock_irq(&node_list_lock);
list_add_tail(&fdtv->list, &node_list);
spin_unlock_irq(&node_list_lock);
err = avc_identify_subunit(fdtv);
if (err)
goto fail;
err = fdtv_dvb_register(fdtv, model_names[fdtv->type]);
if (err)
goto fail;
avc_register_remote_control(fdtv);
return 0;
fail:
spin_lock_irq(&node_list_lock);
list_del(&fdtv->list);
spin_unlock_irq(&node_list_lock);
fdtv_unregister_rc(fdtv);
fail_free:
kfree(fdtv);
return err;
}
static int node_remove(struct device *dev)
{
struct firedtv *fdtv = dev_get_drvdata(dev);
fdtv_dvb_unregister(fdtv);
spin_lock_irq(&node_list_lock);
list_del(&fdtv->list);
spin_unlock_irq(&node_list_lock);
fdtv_unregister_rc(fdtv);
kfree(fdtv);
return 0;
}
static void node_update(struct fw_unit *unit)
{
struct firedtv *fdtv = dev_get_drvdata(&unit->device);
if (fdtv->isochannel >= 0)
cmp_establish_pp_connection(fdtv, fdtv->subunit,
fdtv->isochannel);
}
#define MATCH_FLAGS (IEEE1394_MATCH_VENDOR_ID | IEEE1394_MATCH_MODEL_ID | \
IEEE1394_MATCH_SPECIFIER_ID | IEEE1394_MATCH_VERSION)
#define DIGITAL_EVERYWHERE_OUI 0x001287
#define AVC_UNIT_SPEC_ID_ENTRY 0x00a02d
#define AVC_SW_VERSION_ENTRY 0x010001
static const struct ieee1394_device_id fdtv_id_table[] = {
{
/* FloppyDTV S/CI and FloppyDTV S2 */
.match_flags = MATCH_FLAGS,
.vendor_id = DIGITAL_EVERYWHERE_OUI,
.model_id = 0x000024,
.specifier_id = AVC_UNIT_SPEC_ID_ENTRY,
.version = AVC_SW_VERSION_ENTRY,
}, {
/* FloppyDTV T/CI */
.match_flags = MATCH_FLAGS,
.vendor_id = DIGITAL_EVERYWHERE_OUI,
.model_id = 0x000025,
.specifier_id = AVC_UNIT_SPEC_ID_ENTRY,
.version = AVC_SW_VERSION_ENTRY,
}, {
/* FloppyDTV C/CI */
.match_flags = MATCH_FLAGS,
.vendor_id = DIGITAL_EVERYWHERE_OUI,
.model_id = 0x000026,
.specifier_id = AVC_UNIT_SPEC_ID_ENTRY,
.version = AVC_SW_VERSION_ENTRY,
}, {
/* FireDTV S/CI and FloppyDTV S2 */
.match_flags = MATCH_FLAGS,
.vendor_id = DIGITAL_EVERYWHERE_OUI,
.model_id = 0x000034,
.specifier_id = AVC_UNIT_SPEC_ID_ENTRY,
.version = AVC_SW_VERSION_ENTRY,
}, {
/* FireDTV T/CI */
.match_flags = MATCH_FLAGS,
.vendor_id = DIGITAL_EVERYWHERE_OUI,
.model_id = 0x000035,
.specifier_id = AVC_UNIT_SPEC_ID_ENTRY,
.version = AVC_SW_VERSION_ENTRY,
}, {
/* FireDTV C/CI */
.match_flags = MATCH_FLAGS,
.vendor_id = DIGITAL_EVERYWHERE_OUI,
.model_id = 0x000036,
.specifier_id = AVC_UNIT_SPEC_ID_ENTRY,
.version = AVC_SW_VERSION_ENTRY,
}, {}
};
MODULE_DEVICE_TABLE(ieee1394, fdtv_id_table);
static struct fw_driver fdtv_driver = {
.driver = {
.owner = THIS_MODULE,
.name = "firedtv",
.bus = &fw_bus_type,
.probe = node_probe,
.remove = node_remove,
},
.update = node_update,
.id_table = fdtv_id_table,
};
static int __init fdtv_init(void)
{
int ret;
ret = fw_core_add_address_handler(&fcp_handler, &fcp_region);
if (ret < 0)
return ret;
ret = driver_register(&fdtv_driver.driver);
if (ret < 0)
fw_core_remove_address_handler(&fcp_handler);
return ret;
}
static void __exit fdtv_exit(void)
{
driver_unregister(&fdtv_driver.driver);
fw_core_remove_address_handler(&fcp_handler);
}
module_init(fdtv_init);
module_exit(fdtv_exit);
MODULE_AUTHOR("Andreas Monitzer <andy@monitzer.com>");
MODULE_AUTHOR("Ben Backx <ben@bbackx.com>");
MODULE_DESCRIPTION("FireDTV DVB Driver");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("FireDTV DVB");