lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

firewire: core: optimize propagation of BROADCAST_CHANNEL

Browse Source 
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
Download Patch File Download Diff File Expand all files Collapse all files

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);
}
/*