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firewire: allocate broadcast channel in hardware

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On OHCI 1.1 controllers, let the hardware allocate the broadcast channel
automatically.  This removes a theoretical race condition directly after
a bus reset where it could be possible to read the channel allocation
register with channel 31 still being unallocated.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
This commit is contained in:
Clemens Ladisch 2010-06-10 08:40:49 +02:00
parent 7e0e314f19
commit e91b2787d0
4 changed files with 26 additions and 12 deletions
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16
drivers/firewire/core-card.c
View File

@ -208,13 +208,19 @@ static void allocate_broadcast_channel(struct fw_card *card, int generation)
{
int channel, bandwidth = 0;
fw_iso_resource_manage(card, generation, 1ULL << 31, &channel,
&bandwidth, true, card->bm_transaction_data);
if (channel == 31) {
if (!card->broadcast_channel_allocated) {
fw_iso_resource_manage(card, generation, 1ULL << 31,
&channel, &bandwidth, true,
card->bm_transaction_data);
if (channel != 31) {
fw_notify("failed to allocate broadcast channel\n");
return;
}
card->broadcast_channel_allocated = true;
device_for_each_child(card->device, (void *)(long)generation,
fw_device_set_broadcast_channel);
}
device_for_each_child(card->device, (void *)(long)generation,
fw_device_set_broadcast_channel);
}
static const char gap_count_table[] = {

3
drivers/firewire/core-topology.c
View File

@ -543,7 +543,8 @@ 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->broadcast_channel_allocated = (card->driver->get_features(card) &
FEATURE_CHANNEL_31_ALLOCATED) != 0;
card->node_id = node_id;
/*
* Update node_id before generation to prevent anybody from using

1
drivers/firewire/core.h
View File

@ -39,6 +39,7 @@ struct fw_packet;
#define BROADCAST_CHANNEL_VALID (1 << 30)
#define FEATURE_PRIORITY_BUDGET 0x01
#define FEATURE_CHANNEL_31_ALLOCATED 0x02
#define CSR_STATE_BIT_CMSTR (1 << 8)
#define CSR_STATE_BIT_ABDICATE (1 << 10)

18
drivers/firewire/ohci.c
View File

@ -171,6 +171,7 @@ struct fw_ohci {
int request_generation; /* for timestamping incoming requests */
unsigned quirks;
unsigned int pri_req_max;
unsigned int features;
u32 bus_time;
bool is_root;
@ -1694,7 +1695,7 @@ static int ohci_enable(struct fw_card *card,
{
struct fw_ohci *ohci = fw_ohci(card);
struct pci_dev *dev = to_pci_dev(card->device);
u32 lps, seconds, irqs;
u32 lps, seconds, version, irqs;
int i, ret;
if (software_reset(ohci)) {
@ -1747,10 +1748,19 @@ static int ohci_enable(struct fw_card *card,
reg_write(ohci, OHCI1394_IsochronousCycleTimer, seconds << 25);
ohci->bus_time = seconds & ~0x3f;
version = reg_read(ohci, OHCI1394_Version) & 0x00ff00ff;
if (version >= OHCI_VERSION_1_1) {
reg_write(ohci, OHCI1394_InitialChannelsAvailableHi,
0xfffffffe);
ohci->features |= FEATURE_CHANNEL_31_ALLOCATED;
}
/* Get implemented bits of the priority arbitration request counter. */
reg_write(ohci, OHCI1394_FairnessControl, 0x3f);
ohci->pri_req_max = reg_read(ohci, OHCI1394_FairnessControl) & 0x3f;
reg_write(ohci, OHCI1394_FairnessControl, 0);
if (ohci->pri_req_max != 0)
ohci->features |= FEATURE_PRIORITY_BUDGET;
ar_context_run(&ohci->ar_request_ctx);
ar_context_run(&ohci->ar_response_ctx);
@ -2124,12 +2134,8 @@ static void ohci_write_csr_reg(struct fw_card *card, int csr_offset, u32 value)
static unsigned int ohci_get_features(struct fw_card *card)
{
struct fw_ohci *ohci = fw_ohci(card);
unsigned int features = 0;
if (ohci->pri_req_max != 0)
features |= FEATURE_PRIORITY_BUDGET;
return features;
return ohci->features;
}
static void copy_iso_headers(struct iso_context *ctx, void *p)