1 files changed, 198 insertions, 29 deletions

diff --git a/drivers/firewire/fw-iso.c b/drivers/firewire/fw-iso.c
index e14c03dc0065..2baf1007253e 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>
  *
@@ -18,21 +20,25 @@
  * 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"
 
-int
-fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
-		   int page_count, enum dma_data_direction direction)
+/*
+ * 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)
 {
-	int i, j, retval = -ENOMEM;
+	int i, j;
 	dma_addr_t address;
 
 	buffer->page_count = page_count;
@@ -69,19 +75,21 @@ fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
 	kfree(buffer->pages);
  out:
 	buffer->pages = NULL;
-	return retval;
+
+	return -ENOMEM;
 }
 
 int fw_iso_buffer_map(struct fw_iso_buffer *buffer, struct vm_area_struct *vma)
 {
 	unsigned long uaddr;
-	int i, retval;
+	int i, err;
 
 	uaddr = vma->vm_start;
 	for (i = 0; i < buffer->page_count; i++) {
-		retval = vm_insert_page(vma, uaddr, buffer->pages[i]);
-		if (retval)
-			return retval;
+		err = vm_insert_page(vma, uaddr, buffer->pages[i]);
+		if (err)
+			return err;
+
 		uaddr += PAGE_SIZE;
 	}
 
@@ -105,14 +113,14 @@ void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
 	buffer->pages = NULL;
 }
 
-struct fw_iso_context *
-fw_iso_context_create(struct fw_card *card, int type,
-		      int channel, int speed, size_t header_size,
-		      fw_iso_callback_t callback, void *callback_data)
+struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
+		int type, int channel, int speed, size_t header_size,
+		fw_iso_callback_t callback, void *callback_data)
 {
 	struct fw_iso_context *ctx;
 
-	ctx = card->driver->allocate_iso_context(card, type, header_size);
+	ctx = card->driver->allocate_iso_context(card,
+						 type, channel, header_size);
 	if (IS_ERR(ctx))
 		return ctx;
 
@@ -134,25 +142,186 @@ void fw_iso_context_destroy(struct fw_iso_context *ctx)
 	card->driver->free_iso_context(ctx);
 }
 
-int
-fw_iso_context_start(struct fw_iso_context *ctx, int cycle, int sync, int tags)
+int fw_iso_context_start(struct fw_iso_context *ctx,
+			 int cycle, int sync, int tags)
 {
 	return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
 }
 
-int
-fw_iso_context_queue(struct fw_iso_context *ctx,
-		     struct fw_iso_packet *packet,
-		     struct fw_iso_buffer *buffer,
-		     unsigned long payload)
+int fw_iso_context_queue(struct fw_iso_context *ctx,
+			 struct fw_iso_packet *packet,
+			 struct fw_iso_buffer *buffer,
+			 unsigned long payload)
 {
 	struct fw_card *card = ctx->card;
 
 	return card->driver->queue_iso(ctx, packet, buffer, payload);
 }
 
-int
-fw_iso_context_stop(struct fw_iso_context *ctx)
+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,
+			  u32 channels_mask, u64 offset, bool allocate)
+{
+	__be32 data[2], c, all, old;
+	int i, retry = 5;
+
+	old = all = allocate ? cpu_to_be32(~0) : 0;
+
+	for (i = 0; i < 32; i++) {
+		if (!(channels_mask & 1 << i))
+			continue;
+
+		c = cpu_to_be32(1 << (31 - i));
+		if ((old & c) != (all & 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)
+{
+	u32 mask;
+	u64 offset;
+
+	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;
+
+	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.
+ * 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.
+ *
+ * If generation is stale, deallocations succeed but allocations fail with
+ * channel = -EAGAIN.
+ *
+ * If channel allocation fails, no bandwidth will be allocated either.
+ * If bandwidth allocation fails, no channel will be allocated either.
+ * 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)
+{
+	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);
+	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 (allocate && 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 (allocate && ret < 0 && c >= 0) {
+		deallocate_channel(card, irm_id, generation, c);
+		*channel = ret;
+	}
+}