/* * Isochronous I/O functionality: *   - Isochronous DMA context management *   - Isochronous bus resource management (channels, bandwidth), client side * * Copyright (C) 2006 Kristian Hoegsberg <krh@bitplanet.net> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software Foundation, * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #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(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); int fw_iso_buffer_map_vma(struct fw_iso_buffer *buffer,			  struct vm_area_struct *vma){	unsigned long uaddr;	int i, err; 	uaddr = vma->vm_start;	for (i = 0; i < buffer->page_count; i++) {		err = vm_insert_page(vma, uaddr, buffer->pages[i]);		if (err)			return err; 		uaddr += PAGE_SIZE;	} 	return 0;} 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){	int 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; 			/* 1394-1995 IRM, fall through to 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 * * 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);