1 files changed, 379 insertions, 0 deletions
diff --git a/drivers/firewire/core-iso.c b/drivers/firewire/core-iso.c
new file mode 100644
index 000000000..af70e74f9
--- /dev/null
+++ b/drivers/firewire/core-iso.c
@@ -0,0 +1,379 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Isochronous I/O functionality:
+ *   - Isochronous DMA context management
+ *   - Isochronous bus resource management (channels, bandwidth), client side
+ *
+ * Copyright (C) 2006 Kristian Hoegsberg <krh@bitplanet.net>
+ */
+
+#include <linux/dma-mapping.h>
+#include <linux/errno.h>
+#include <linux/firewire.h>
+#include <linux/firewire-constants.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/vmalloc.h>
+#include <linux/export.h>
+
+#include <asm/byteorder.h>
+
+#include "core.h"
+
+/*
+ * Isochronous DMA context management
+ */
+
+int fw_iso_buffer_alloc(struct fw_iso_buffer *buffer, int page_count)
+{
+	int i;
+
+	buffer->page_count = 0;
+	buffer->page_count_mapped = 0;
+	buffer->pages = kmalloc_array(page_count, sizeof(buffer->pages[0]),
+				      GFP_KERNEL);
+	if (buffer->pages == NULL)
+		return -ENOMEM;
+
+	for (i = 0; i < page_count; i++) {
+		buffer->pages[i] = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
+		if (buffer->pages[i] == NULL)
+			break;
+	}
+	buffer->page_count = i;
+	if (i < page_count) {
+		fw_iso_buffer_destroy(buffer, NULL);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+int fw_iso_buffer_map_dma(struct fw_iso_buffer *buffer, struct fw_card *card,
+			  enum dma_data_direction direction)
+{
+	dma_addr_t address;
+	int i;
+
+	buffer->direction = direction;
+
+	for (i = 0; i < buffer->page_count; i++) {
+		address = dma_map_page(card->device, buffer->pages[i],
+				       0, PAGE_SIZE, direction);
+		if (dma_mapping_error(card->device, address))
+			break;
+
+		set_page_private(buffer->pages[i], address);
+	}
+	buffer->page_count_mapped = i;
+	if (i < buffer->page_count)
+		return -ENOMEM;
+
+	return 0;
+}
+
+int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
+		       int page_count, enum dma_data_direction direction)
+{
+	int ret;
+
+	ret = fw_iso_buffer_alloc(buffer, page_count);
+	if (ret < 0)
+		return ret;
+
+	ret = fw_iso_buffer_map_dma(buffer, card, direction);
+	if (ret < 0)
+		fw_iso_buffer_destroy(buffer, card);
+
+	return ret;
+}
+EXPORT_SYMBOL(fw_iso_buffer_init);
+
+void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
+			   struct fw_card *card)
+{
+	int i;
+	dma_addr_t address;
+
+	for (i = 0; i < buffer->page_count_mapped; i++) {
+		address = page_private(buffer->pages[i]);
+		dma_unmap_page(card->device, address,
+			       PAGE_SIZE, buffer->direction);
+	}
+	for (i = 0; i < buffer->page_count; i++)
+		__free_page(buffer->pages[i]);
+
+	kfree(buffer->pages);
+	buffer->pages = NULL;
+	buffer->page_count = 0;
+	buffer->page_count_mapped = 0;
+}
+EXPORT_SYMBOL(fw_iso_buffer_destroy);
+
+/* Convert DMA address to offset into virtually contiguous buffer. */
+size_t fw_iso_buffer_lookup(struct fw_iso_buffer *buffer, dma_addr_t completed)
+{
+	size_t i;
+	dma_addr_t address;
+	ssize_t offset;
+
+	for (i = 0; i < buffer->page_count; i++) {
+		address = page_private(buffer->pages[i]);
+		offset = (ssize_t)completed - (ssize_t)address;
+		if (offset > 0 && offset <= PAGE_SIZE)
+			return (i << PAGE_SHIFT) + offset;
+	}
+
+	return 0;
+}
+
+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, channel, header_size);
+	if (IS_ERR(ctx))
+		return ctx;
+
+	ctx->card = card;
+	ctx->type = type;
+	ctx->channel = channel;
+	ctx->speed = speed;
+	ctx->header_size = header_size;
+	ctx->callback.sc = callback;
+	ctx->callback_data = callback_data;
+
+	return ctx;
+}
+EXPORT_SYMBOL(fw_iso_context_create);
+
+void fw_iso_context_destroy(struct fw_iso_context *ctx)
+{
+	ctx->card->driver->free_iso_context(ctx);
+}
+EXPORT_SYMBOL(fw_iso_context_destroy);
+
+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);
+}
+EXPORT_SYMBOL(fw_iso_context_start);
+
+int fw_iso_context_set_channels(struct fw_iso_context *ctx, u64 *channels)
+{
+	return ctx->card->driver->set_iso_channels(ctx, channels);
+}
+
+int fw_iso_context_queue(struct fw_iso_context *ctx,
+			 struct fw_iso_packet *packet,
+			 struct fw_iso_buffer *buffer,
+			 unsigned long payload)
+{
+	return ctx->card->driver->queue_iso(ctx, packet, buffer, payload);
+}
+EXPORT_SYMBOL(fw_iso_context_queue);
+
+void fw_iso_context_queue_flush(struct fw_iso_context *ctx)
+{
+	ctx->card->driver->flush_queue_iso(ctx);
+}
+EXPORT_SYMBOL(fw_iso_context_queue_flush);
+
+int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
+{
+	return ctx->card->driver->flush_iso_completions(ctx);
+}
+EXPORT_SYMBOL(fw_iso_context_flush_completions);
+
+int fw_iso_context_stop(struct fw_iso_context *ctx)
+{
+	return ctx->card->driver->stop_iso(ctx);
+}
+EXPORT_SYMBOL(fw_iso_context_stop);
+
+/*
+ * 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)
+{
+	int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
+	__be32 data[2];
+
+	/*
+	 * 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)
+			return -EBUSY;
+
+		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, 8)) {
+		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 bit, all, old;
+	__be32 data[2];
+	int channel, ret = -EIO, retry = 5;
+
+	old = all = allocate ? cpu_to_be32(~0) : 0;
+
+	for (channel = 0; channel < 32; channel++) {
+		if (!(channels_mask & 1 << channel))
+			continue;
+
+		ret = -EBUSY;
+
+		bit = cpu_to_be32(1 << (31 - channel));
+		if ((old & bit) != (all & bit))
+			continue;
+
+		data[0] = old;
+		data[1] = old ^ bit;
+		switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
+					   irm_id, generation, SCODE_100,
+					   offset, data, 8)) {
+		case RCODE_GENERATION:
+			/* A generation change frees all channels. */
+			return allocate ? -EAGAIN : channel;
+
+		case RCODE_COMPLETE:
+			if (data[0] == old)
+				return channel;
+
+			old = data[0];
+
+			/* Is the IRM 1394a-2000 compliant? */
+			if ((data[0] & bit) == (data[1] & bit))
+				continue;
+
+			fallthrough;	/* It's a 1394-1995 IRM, retry */
+		default:
+			if (retry) {
+				retry--;
+				channel--;
+			} else {
+				ret = -EIO;
+			}
+		}
+	}
+
+	return ret;
+}
+
+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
+ * @card: card interface for this action
+ * @generation: bus generation
+ * @channels_mask: bitmask for channel allocation
+ * @channel: pointer for returning channel allocation result
+ * @bandwidth: pointer for returning bandwidth allocation result
+ * @allocate: whether to allocate (true) or deallocate (false)
+ *
+ * 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) {
+		if (c >= 0)
+			deallocate_channel(card, irm_id, generation, c);
+		*channel = ret;
+	}
+}
+EXPORT_SYMBOL(fw_iso_resource_manage);