diff options
Diffstat (limited to 'drivers/firewire/fw-iso.c')
| -rw-r--r-- | drivers/firewire/fw-iso.c | 38 |
1 files changed, 22 insertions, 16 deletions
diff --git a/drivers/firewire/fw-iso.c b/drivers/firewire/fw-iso.c index a7b57b253b0..f511d16efae 100644 --- a/drivers/firewire/fw-iso.c +++ b/drivers/firewire/fw-iso.c @@ -204,17 +204,19 @@ static int manage_bandwidth(struct fw_card *card, int irm_id, int generation, } static int manage_channel(struct fw_card *card, int irm_id, int generation, - __be32 channels_mask, u64 offset, bool allocate) + u32 channels_mask, u64 offset, bool allocate) { - __be32 data[2], c, old = allocate ? cpu_to_be32(~0) : 0; + __be32 data[2], c, all, old; int i, retry = 5; + old = all = allocate ? cpu_to_be32(~0) : 0; + for (i = 0; i < 32; i++) { - c = cpu_to_be32(1 << (31 - i)); - if (!(channels_mask & c)) + if (!(channels_mask & 1 << i)) continue; - if (allocate == !(old & c)) + c = cpu_to_be32(1 << (31 - i)); + if ((old & c) != (all & c)) continue; data[0] = old; @@ -233,7 +235,7 @@ static int manage_channel(struct fw_card *card, int irm_id, int generation, old = data[0]; /* Is the IRM 1394a-2000 compliant? */ - if ((data[0] & c) != (data[1] & c)) + if ((data[0] & c) == (data[1] & c)) continue; /* 1394-1995 IRM, fall through to retry. */ @@ -249,11 +251,10 @@ static int manage_channel(struct fw_card *card, int irm_id, int generation, static void deallocate_channel(struct fw_card *card, int irm_id, int generation, int channel) { - __be32 mask; + u32 mask; u64 offset; - mask = channel < 32 ? cpu_to_be32(1 << (31 - channel)) : - cpu_to_be32(1 << (63 - channel)); + mask = channel < 32 ? 1 << channel : 1 << (channel - 32); offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI : CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO; @@ -266,7 +267,12 @@ static void deallocate_channel(struct fw_card *card, int irm_id, * In parameters: card, generation, channels_mask, bandwidth, allocate * Out parameters: channel, bandwidth * This function blocks (sleeps) during communication with the IRM. + * * Allocates or deallocates at most one channel out of channels_mask. + * channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0. + * (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for + * channel 0 and LSB for channel 63.) + * Allocates or deallocates as many bandwidth allocation units as specified. * * Returns channel < 0 if no channel was allocated or deallocated. * Returns bandwidth = 0 if no bandwidth was allocated or deallocated. @@ -274,17 +280,17 @@ static void deallocate_channel(struct fw_card *card, int irm_id, * If generation is stale, deallocations succeed but allocations fail with * channel = -EAGAIN. * - * If channel (de)allocation fails, bandwidth (de)allocation fails too. + * If channel allocation fails, no bandwidth will be allocated either. * If bandwidth allocation fails, no channel will be allocated either. - * If bandwidth deallocation fails, channel deallocation may still have been - * successful. + * But deallocations of channel and bandwidth are tried independently + * of each other's success. */ void fw_iso_resource_manage(struct fw_card *card, int generation, u64 channels_mask, int *channel, int *bandwidth, bool allocate) { - __be32 channels_hi = cpu_to_be32(channels_mask >> 32); - __be32 channels_lo = cpu_to_be32(channels_mask); + u32 channels_hi = channels_mask; /* channels 31...0 */ + u32 channels_lo = channels_mask >> 32; /* channels 63...32 */ int irm_id, ret, c = -EINVAL; spin_lock_irq(&card->lock); @@ -302,7 +308,7 @@ void fw_iso_resource_manage(struct fw_card *card, int generation, } *channel = c; - if (channels_mask != 0 && c < 0) + if (allocate && channels_mask != 0 && c < 0) *bandwidth = 0; if (*bandwidth == 0) @@ -312,7 +318,7 @@ void fw_iso_resource_manage(struct fw_card *card, int generation, if (ret < 0) *bandwidth = 0; - if (ret < 0 && c >= 0 && allocate) { + if (allocate && ret < 0 && c >= 0) { deallocate_channel(card, irm_id, generation, c); *channel = ret; } |