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/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)