1 files changed, 22 insertions, 16 deletions

diff --git a/drivers/firewire/fw-iso.c b/drivers/firewire/fw-iso.c
index a7b57b253b06..f511d16efaee 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;
         }