1 files changed, 170 insertions, 6 deletions

diff --git a/drivers/firewire/fw-iso.c b/drivers/firewire/fw-iso.c
index 39f3bacee404..a7b57b253b06 100644
--- a/drivers/firewire/fw-iso.c
+++ b/drivers/firewire/fw-iso.c
@@ -1,5 +1,7 @@
 /*
- * Isochronous IO functionality
+ * Isochronous I/O functionality:
+ *   - Isochronous DMA context management
+ *   - Isochronous bus resource management (channels, bandwidth), client side
  *
  * Copyright (C) 2006 Kristian Hoegsberg <krh@bitplanet.net>
  *
@@ -18,15 +20,20 @@
  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
-#include <linux/kernel.h>
-#include <linux/module.h>
 #include <linux/dma-mapping.h>
-#include <linux/vmalloc.h>
+#include <linux/errno.h>
+#include <linux/firewire-constants.h>
+#include <linux/kernel.h>
 #include <linux/mm.h>
+#include <linux/spinlock.h>
+#include <linux/vmalloc.h>
 
-#include "fw-transaction.h"
 #include "fw-topology.h"
-#include "fw-device.h"
+#include "fw-transaction.h"
+
+/*
+ * Isochronous DMA context management
+ */
 
 int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
                        int page_count, enum dma_data_direction direction)
@@ -153,3 +160,160 @@ int fw_iso_context_stop(struct fw_iso_context *ctx)
 {
         return ctx->card->driver->stop_iso(ctx);
 }
+
+/*
+ * Isochronous bus resource management (channels, bandwidth), client side
+ */
+
+static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
+                            int bandwidth, bool allocate)
+{
+        __be32 data[2];
+        int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
+
+        /*
+         * On a 1394a IRM with low contention, try < 1 is enough.
+         * On a 1394-1995 IRM, we need at least try < 2.
+         * Let's just do try < 5.
+         */
+        for (try = 0; try < 5; try++) {
+                new = allocate ? old - bandwidth : old + bandwidth;
+                if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
+                        break;
+
+                data[0] = cpu_to_be32(old);
+                data[1] = cpu_to_be32(new);
+                switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
+                                irm_id, generation, SCODE_100,
+                                CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
+                                data, sizeof(data))) {
+                case RCODE_GENERATION:
+                        /* A generation change frees all bandwidth. */
+                        return allocate ? -EAGAIN : bandwidth;
+
+                case RCODE_COMPLETE:
+                        if (be32_to_cpup(data) == old)
+                                return bandwidth;
+
+                        old = be32_to_cpup(data);
+                        /* Fall through. */
+                }
+        }
+
+        return -EIO;
+}
+
+static int manage_channel(struct fw_card *card, int irm_id, int generation,
+                          __be32 channels_mask, u64 offset, bool allocate)
+{
+        __be32 data[2], c, old = allocate ? cpu_to_be32(~0) : 0;
+        int i, retry = 5;
+
+        for (i = 0; i < 32; i++) {
+                c = cpu_to_be32(1 << (31 - i));
+                if (!(channels_mask & c))
+                        continue;
+
+                if (allocate == !(old & c))
+                        continue;
+
+                data[0] = old;
+                data[1] = old ^ c;
+                switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
+                                           irm_id, generation, SCODE_100,
+                                           offset, data, sizeof(data))) {
+                case RCODE_GENERATION:
+                        /* A generation change frees all channels. */
+                        return allocate ? -EAGAIN : i;
+
+                case RCODE_COMPLETE:
+                        if (data[0] == old)
+                                return i;
+
+                        old = data[0];
+
+                        /* Is the IRM 1394a-2000 compliant? */
+                        if ((data[0] & c) != (data[1] & c))
+                                continue;
+
+                        /* 1394-1995 IRM, fall through to retry. */
+                default:
+                        if (retry--)
+                                i--;
+                }
+        }
+
+        return -EIO;
+}
+
+static void deallocate_channel(struct fw_card *card, int irm_id,
+                               int generation, int channel)
+{
+        __be32 mask;
+        u64 offset;
+
+        mask = channel < 32 ? cpu_to_be32(1 << (31 - channel)) :
+                              cpu_to_be32(1 << (63 - channel));
+        offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
+                                CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
+
+        manage_channel(card, irm_id, generation, mask, offset, false);
+}
+
+/**
+ * fw_iso_resource_manage - Allocate or deallocate a channel and/or bandwidth
+ *
+ * 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.
+ *
+ * Returns channel < 0 if no channel was allocated or deallocated.
+ * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
+ *
+ * If generation is stale, deallocations succeed but allocations fail with
+ * channel = -EAGAIN.
+ *
+ * If channel (de)allocation fails, bandwidth (de)allocation fails too.
+ * If bandwidth allocation fails, no channel will be allocated either.
+ * If bandwidth deallocation fails, channel deallocation may still have been
+ * successful.
+ */
+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);
+        int irm_id, ret, c = -EINVAL;
+
+        spin_lock_irq(&card->lock);
+        irm_id = card->irm_node->node_id;
+        spin_unlock_irq(&card->lock);
+
+        if (channels_hi)
+                c = manage_channel(card, irm_id, generation, channels_hi,
+                    CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI, allocate);
+        if (channels_lo && c < 0) {
+                c = manage_channel(card, irm_id, generation, channels_lo,
+                    CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO, allocate);
+                if (c >= 0)
+                        c += 32;
+        }
+        *channel = c;
+
+        if (channels_mask != 0 && c < 0)
+                *bandwidth = 0;
+
+        if (*bandwidth == 0)
+                return;
+
+        ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
+        if (ret < 0)
+                *bandwidth = 0;
+
+        if (ret < 0 && c >= 0 && allocate) {
+                deallocate_channel(card, irm_id, generation, c);
+                *channel = ret;
+        }
+}