firewire: allocate broadcast channel in hardware
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>
diff --git a/drivers/firewire/core-card.c b/drivers/firewire/core-card.c
index 7c4cf6c..faf2eee 100644
--- a/drivers/firewire/core-card.c
+++ b/drivers/firewire/core-card.c
@@ -208,13 +208,19 @@
{
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[] = {
diff --git a/drivers/firewire/core-topology.c b/drivers/firewire/core-topology.c
index ca3c653..00a556f 100644
--- a/drivers/firewire/core-topology.c
+++ b/drivers/firewire/core-topology.c
@@ -543,7 +543,8 @@
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
diff --git a/drivers/firewire/core.h b/drivers/firewire/core.h
index a9ace1f..3f9e39b 100644
--- a/drivers/firewire/core.h
+++ b/drivers/firewire/core.h
@@ -39,6 +39,7 @@
#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)
diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index 1dcc2e4..51a5580 100644
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -171,6 +171,7 @@
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 @@
{
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 @@
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 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)