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firewire: core: optimize propagation of BROADCAST_CHANNEL 

Cache the test result of whether a device implements BROADCAST_CHANNEL.
This minimizes traffic on the bus after each bus reset.  A majority of
devices does not implement BROADCAST_CHANNEL.

Remove busy retries; just rely on the hardware to retry requests to busy
responders.  Remove unnecessary log messages.

Rename the flag is_irm to broadcast_channel_allocated to better reflect
its meaning.  Reset the flag earlier in fw_core_handle_bus_reset.

Pass the generation down as a call parameter; that way generation can't
be newer than card->broadcast_channel_allocated and device->node_id.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
This commit is contained in:
Stefan Richter 2009-03-10 21:09:28 +01:00
parent cbae787c0f
commit 7889b60ee7
5 changed files with 52 additions and 90 deletions
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85
drivers/firewire/fw-card.c
View File

@ -181,83 +181,9 @@ void fw_core_remove_descriptor(struct fw_descriptor *desc)
mutex_unlock(&card_mutex);
}
#define IRM_RETRIES 2
/*
* The abi is set by device_for_each_child(), even though we have no use
* for data, nor do we have a meaningful return value.
*/
int fw_irm_set_broadcast_channel_register(struct device *dev, void *data)
static int set_broadcast_channel(struct device *dev, void *data)
{
struct fw_device *d;
int rcode;
int node_id;
int max_speed;
int retries;
int generation;
__be32 regval;
struct fw_card *card;
d = fw_device(dev);
/* FIXME: do we need locking here? */
generation = d->generation;
smp_rmb(); /* Ensure generation is at least as old as node_id */
node_id = d->node_id;
max_speed = d->max_speed;
retries = IRM_RETRIES;
card = d->card;
tryagain_r:
rcode = fw_run_transaction(card, TCODE_READ_QUADLET_REQUEST,
node_id, generation, max_speed,
CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
&regval, 4);
switch (rcode) {
case RCODE_BUSY:
if (retries--)
goto tryagain_r;
fw_notify("node %x read broadcast channel busy\n",
node_id);
return 0;
default:
fw_notify("node %x read broadcast channel failed %x\n",
node_id, rcode);
return 0;
case RCODE_COMPLETE:
/*
* Paranoid reporting of nonstandard broadcast channel
* contents goes here
*/
if (regval != cpu_to_be32(BROADCAST_CHANNEL_INITIAL))
return 0;
break;
}
retries = IRM_RETRIES;
regval = cpu_to_be32(BROADCAST_CHANNEL_INITIAL |
BROADCAST_CHANNEL_VALID);
tryagain_w:
rcode = fw_run_transaction(card,
TCODE_WRITE_QUADLET_REQUEST, node_id,
generation, max_speed,
CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
&regval, 4);
switch (rcode) {
case RCODE_BUSY:
if (retries--)
goto tryagain_w;
fw_notify("node %x write broadcast channel busy\n",
node_id);
return 0;
default:
fw_notify("node %x write broadcast channel failed %x\n",
node_id, rcode);
return 0;
case RCODE_COMPLETE:
return 0;
}
fw_device_set_broadcast_channel(fw_device(dev), (long)data);
return 0;
}
@ -268,9 +194,9 @@ static void allocate_broadcast_channel(struct fw_card *card, int generation)
fw_iso_resource_manage(card, generation, 1ULL << 31,
&channel, &bandwidth, true);
if (channel == 31) {
card->is_irm = true;
device_for_each_child(card->device, NULL,
fw_irm_set_broadcast_channel_register);
card->broadcast_channel_allocated = true;
device_for_each_child(card->device, (void *)(long)generation,
set_broadcast_channel);
}
}
@ -302,7 +228,6 @@ static void fw_card_bm_work(struct work_struct *work)
__be32 lock_data[2];
spin_lock_irqsave(&card->lock, flags);
card->is_irm = false;
if (card->local_node == NULL) {
spin_unlock_irqrestore(&card->lock, flags);

45
drivers/firewire/fw-device.c
View File

@ -518,7 +518,7 @@ static int read_bus_info_block(struct fw_device *device, int generation)
kfree(old_rom);
ret = 0;
device->cmc = rom[2] & 1 << 30;
device->cmc = rom[2] >> 30 & 1;
out:
kfree(rom);
@ -756,6 +756,44 @@ static int lookup_existing_device(struct device *dev, void *data)
return match;
}
enum { BC_UNKNOWN = 0, BC_UNIMPLEMENTED, BC_IMPLEMENTED, };
void fw_device_set_broadcast_channel(struct fw_device *device, int generation)
{
struct fw_card *card = device->card;
__be32 data;
int rcode;
if (!card->broadcast_channel_allocated)
return;
if (device->bc_implemented == BC_UNKNOWN) {
rcode = fw_run_transaction(card, TCODE_READ_QUADLET_REQUEST,
device->node_id, generation, device->max_speed,
CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
&data, 4);
switch (rcode) {
case RCODE_COMPLETE:
if (data & cpu_to_be32(1 << 31)) {
device->bc_implemented = BC_IMPLEMENTED;
break;
}
/* else fall through to case address error */
case RCODE_ADDRESS_ERROR:
device->bc_implemented = BC_UNIMPLEMENTED;
}
}
if (device->bc_implemented == BC_IMPLEMENTED) {
data = cpu_to_be32(BROADCAST_CHANNEL_INITIAL |
BROADCAST_CHANNEL_VALID);
fw_run_transaction(card, TCODE_WRITE_QUADLET_REQUEST,
device->node_id, generation, device->max_speed,
CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
&data, 4);
}
}
static void fw_device_init(struct work_struct *work)
{
struct fw_device *device =
@ -849,9 +887,8 @@ static void fw_device_init(struct work_struct *work)
device->config_rom[3], device->config_rom[4],
1 << device->max_speed);
device->config_rom_retries = 0;
if (device->card->is_irm)
fw_irm_set_broadcast_channel_register(&device->device,
NULL);
fw_device_set_broadcast_channel(device, device->generation);
}
/*

5
drivers/firewire/fw-device.h
View File

@ -71,7 +71,6 @@ struct fw_device {
int node_id;
int generation;
unsigned max_speed;
bool cmc;
struct fw_card *card;
struct device device;
@ -81,6 +80,9 @@ struct fw_device {
u32 *config_rom;
size_t config_rom_length;
int config_rom_retries;
unsigned cmc:1;
unsigned bc_implemented:2;
struct delayed_work work;
struct fw_attribute_group attribute_group;
};
@ -109,6 +111,7 @@ static inline void fw_device_put(struct fw_device *device)
struct fw_device *fw_device_get_by_devt(dev_t devt);
int fw_device_enable_phys_dma(struct fw_device *device);
void fw_device_set_broadcast_channel(struct fw_device *device, int generation);
void fw_device_cdev_update(struct fw_device *device);
void fw_device_cdev_remove(struct fw_device *device);

1
drivers/firewire/fw-topology.c
View File

@ -526,6 +526,7 @@ void fw_core_handle_bus_reset(struct fw_card *card, int node_id, int generation,
spin_lock_irqsave(&card->lock, flags);
card->broadcast_channel_allocated = false;
card->node_id = node_id;
/*
* Update node_id before generation to prevent anybody from using

6
drivers/firewire/fw-transaction.h
View File

@ -230,11 +230,6 @@ struct fw_card {
u8 color; /* must be u8 to match the definition in struct fw_node */
int gap_count;
bool beta_repeaters_present;
/*
* Set if the local device is the IRM and the broadcast channel
* was allocated.
*/
bool is_irm;
int index;
@ -245,6 +240,7 @@ struct fw_card {
int bm_retries;
int bm_generation;
bool broadcast_channel_allocated;
u32 broadcast_channel;
u32 topology_map[(CSR_TOPOLOGY_MAP_END - CSR_TOPOLOGY_MAP) / 4];
};