arch/sh/drivers/dma/dma-api.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * arch/sh/drivers/dma/dma-api.c
  *
  * SuperH-specific DMA management API
  *
  * Copyright (C) 2003, 2004, 2005  Paul Mundt
  */
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/spinlock.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <linux/list.h>
 #include <linux/platform_device.h>
 #include <linux/mm.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <asm/dma.h>

 DEFINE_SPINLOCK(dma_spin_lock);
 static LIST_HEAD(registered_dmac_list);

 struct dma_info *get_dma_info(unsigned int chan)
 {
 	struct dma_info *info;

 	/*
 	 * Look for each DMAC's range to determine who the owner of
 	 * the channel is.
 	 */
 	list_for_each_entry(info, &registered_dmac_list, list) {
 		if ((chan <  info->first_vchannel_nr) ||
 		    (chan >= info->first_vchannel_nr + info->nr_channels))
 			continue;

 		return info;
 	}

 	return NULL;
 }
 EXPORT_SYMBOL(get_dma_info);

 struct dma_info *get_dma_info_by_name(const char *dmac_name)
 {
 	struct dma_info *info;

 	list_for_each_entry(info, &registered_dmac_list, list) {
 		if (dmac_name && (strcmp(dmac_name, info->name) != 0))
 			continue;
 		else
 			return info;
 	}

 	return NULL;
 }
 EXPORT_SYMBOL(get_dma_info_by_name);

 static unsigned int get_nr_channels(void)
 {
 	struct dma_info *info;
 	unsigned int nr = 0;

 	if (unlikely(list_empty(&registered_dmac_list)))
 		return nr;

 	list_for_each_entry(info, &registered_dmac_list, list)
 		nr += info->nr_channels;

 	return nr;
 }

 struct dma_channel *get_dma_channel(unsigned int chan)
 {
 	struct dma_info *info = get_dma_info(chan);
 	struct dma_channel *channel;
 	int i;

 	if (unlikely(!info))
 		return ERR_PTR(-EINVAL);

 	for (i = 0; i < info->nr_channels; i++) {
 		channel = &info->channels[i];
 		if (channel->vchan == chan)
 			return channel;
 	}

 	return NULL;
 }
 EXPORT_SYMBOL(get_dma_channel);

 int get_dma_residue(unsigned int chan)
 {
 	struct dma_info *info = get_dma_info(chan);
 	struct dma_channel *channel = get_dma_channel(chan);

 	if (info->ops->get_residue)
 		return info->ops->get_residue(channel);

 	return 0;
 }
 EXPORT_SYMBOL(get_dma_residue);

 static int search_cap(const char **haystack, const char *needle)
 {
 	const char **p;

 	for (p = haystack; *p; p++)
 		if (strcmp(*p, needle) == 0)
 			return 1;

 	return 0;
 }

 /**
  * request_dma_bycap - Allocate a DMA channel based on its capabilities
  * @dmac: List of DMA controllers to search
  * @caps: List of capabilities
  *
  * Search all channels of all DMA controllers to find a channel which
  * matches the requested capabilities. The result is the channel
  * number if a match is found, or %-ENODEV if no match is found.
  *
  * Note that not all DMA controllers export capabilities, in which
  * case they can never be allocated using this API, and so
  * request_dma() must be used specifying the channel number.
  */
 int request_dma_bycap(const char **dmac, const char **caps, const char *dev_id)
 {
 	unsigned int found = 0;
 	struct dma_info *info;
 	const char **p;
 	int i;

 	BUG_ON(!dmac || !caps);

 	list_for_each_entry(info, &registered_dmac_list, list)
 		if (strcmp(*dmac, info->name) == 0) {
 			found = 1;
 			break;
 		}

 	if (!found)
 		return -ENODEV;

 	for (i = 0; i < info->nr_channels; i++) {
 		struct dma_channel *channel = &info->channels[i];

 		if (unlikely(!channel->caps))
 			continue;

 		for (p = caps; *p; p++) {
 			if (!search_cap(channel->caps, *p))
 				break;
 			if (request_dma(channel->chan, dev_id) == 0)
 				return channel->chan;
 		}
 	}

 	return -EINVAL;
 }
 EXPORT_SYMBOL(request_dma_bycap);

 int dmac_search_free_channel(const char *dev_id)
 {
 	struct dma_channel *channel = { 0 };
 	struct dma_info *info = get_dma_info(0);
 	int i;

 	for (i = 0; i < info->nr_channels; i++) {
 		channel = &info->channels[i];
 		if (unlikely(!channel))
 			return -ENODEV;

 		if (atomic_read(&channel->busy) == 0)
 			break;
 	}

 	if (info->ops->request) {
 		int result = info->ops->request(channel);
 		if (result)
 			return result;

 		atomic_set(&channel->busy, 1);
 		return channel->chan;
 	}

 	return -ENOSYS;
 }

 int request_dma(unsigned int chan, const char *dev_id)
 {
 	struct dma_channel *channel = { 0 };
 	struct dma_info *info = get_dma_info(chan);
 	int result;

 	channel = get_dma_channel(chan);
 	if (atomic_xchg(&channel->busy, 1))
 		return -EBUSY;

 	strscpy(channel->dev_id, dev_id, sizeof(channel->dev_id));

 	if (info->ops->request) {
 		result = info->ops->request(channel);
 		if (result)
 			atomic_set(&channel->busy, 0);

 		return result;
 	}

 	return 0;
 }
 EXPORT_SYMBOL(request_dma);

 void free_dma(unsigned int chan)
 {
 	struct dma_info *info = get_dma_info(chan);
 	struct dma_channel *channel = get_dma_channel(chan);

 	if (info->ops->free)
 		info->ops->free(channel);

 	atomic_set(&channel->busy, 0);
 }
 EXPORT_SYMBOL(free_dma);

 void dma_wait_for_completion(unsigned int chan)
 {
 	struct dma_info *info = get_dma_info(chan);
 	struct dma_channel *channel = get_dma_channel(chan);

 	if (channel->flags & DMA_TEI_CAPABLE) {
 		wait_event(channel->wait_queue,
 			   (info->ops->get_residue(channel) == 0));
 		return;
 	}

 	while (info->ops->get_residue(channel))
 		cpu_relax();
 }
 EXPORT_SYMBOL(dma_wait_for_completion);

 int register_chan_caps(const char *dmac, struct dma_chan_caps *caps)
 {
 	struct dma_info *info;
 	unsigned int found = 0;
 	int i;

 	list_for_each_entry(info, &registered_dmac_list, list)
 		if (strcmp(dmac, info->name) == 0) {
 			found = 1;
 			break;
 		}

 	if (unlikely(!found))
 		return -ENODEV;

 	for (i = 0; i < info->nr_channels; i++, caps++) {
 		struct dma_channel *channel;

 		if ((info->first_channel_nr + i) != caps->ch_num)
 			return -EINVAL;

 		channel = &info->channels[i];
 		channel->caps = caps->caplist;
 	}

 	return 0;
 }
 EXPORT_SYMBOL(register_chan_caps);

 void dma_configure_channel(unsigned int chan, unsigned long flags)
 {
 	struct dma_info *info = get_dma_info(chan);
 	struct dma_channel *channel = get_dma_channel(chan);

 	if (info->ops->configure)
 		info->ops->configure(channel, flags);
 }
 EXPORT_SYMBOL(dma_configure_channel);

 int dma_xfer(unsigned int chan, unsigned long from,
 	     unsigned long to, size_t size, unsigned int mode)
 {
 	struct dma_info *info = get_dma_info(chan);
 	struct dma_channel *channel = get_dma_channel(chan);

 	channel->sar	= from;
 	channel->dar	= to;
 	channel->count	= size;
 	channel->mode	= mode;

 	return info->ops->xfer(channel);
 }
 EXPORT_SYMBOL(dma_xfer);

 int dma_extend(unsigned int chan, unsigned long op, void *param)
 {
 	struct dma_info *info = get_dma_info(chan);
 	struct dma_channel *channel = get_dma_channel(chan);

 	if (info->ops->extend)
 		return info->ops->extend(channel, op, param);

 	return -ENOSYS;
 }
 EXPORT_SYMBOL(dma_extend);

 static int dma_proc_show(struct seq_file *m, void *v)
 {
 	struct dma_info *info = v;

 	if (list_empty(&registered_dmac_list))
 		return 0;

 	/*
 	 * Iterate over each registered DMAC
 	 */
 	list_for_each_entry(info, &registered_dmac_list, list) {
 		int i;

 		/*
 		 * Iterate over each channel
 		 */
 		for (i = 0; i < info->nr_channels; i++) {
 			struct dma_channel *channel = info->channels + i;

 			if (!(channel->flags & DMA_CONFIGURED))
 				continue;

 			seq_printf(m, "%2d: %14s    %s\n", i,
 				   info->name, channel->dev_id);
 		}
 	}

 	return 0;
 }

 int register_dmac(struct dma_info *info)
 {
 	unsigned int total_channels, i;

 	INIT_LIST_HEAD(&info->list);

 	printk(KERN_INFO "DMA: Registering %s handler (%d channel%s).\n",
 	       info->name, info->nr_channels, info->nr_channels > 1 ? "s" : "");

 	BUG_ON((info->flags & DMAC_CHANNELS_CONFIGURED) && !info->channels);

 	info->pdev = platform_device_register_simple(info->name, -1,
 						     NULL, 0);
 	if (IS_ERR(info->pdev))
 		return PTR_ERR(info->pdev);

 	/*
 	 * Don't touch pre-configured channels
 	 */
 	if (!(info->flags & DMAC_CHANNELS_CONFIGURED)) {
 		unsigned int size;

 		size = sizeof(struct dma_channel) * info->nr_channels;

 		info->channels = kzalloc(size, GFP_KERNEL);
 		if (!info->channels)
 			return -ENOMEM;
 	}

 	total_channels = get_nr_channels();
 	info->first_vchannel_nr = total_channels;
 	for (i = 0; i < info->nr_channels; i++) {
 		struct dma_channel *chan = &info->channels[i];

 		atomic_set(&chan->busy, 0);

 		chan->chan  = info->first_channel_nr + i;
 		chan->vchan = info->first_channel_nr + i + total_channels;

 		memcpy(chan->dev_id, "Unused", 7);

 		if (info->flags & DMAC_CHANNELS_TEI_CAPABLE)
 			chan->flags |= DMA_TEI_CAPABLE;

 		init_waitqueue_head(&chan->wait_queue);
 		dma_create_sysfs_files(chan, info);
 	}

 	list_add(&info->list, &registered_dmac_list);

 	return 0;
 }
 EXPORT_SYMBOL(register_dmac);

 void unregister_dmac(struct dma_info *info)
 {
 	unsigned int i;

 	for (i = 0; i < info->nr_channels; i++)
 		dma_remove_sysfs_files(info->channels + i, info);

 	if (!(info->flags & DMAC_CHANNELS_CONFIGURED))
 		kfree(info->channels);

 	list_del(&info->list);
 	platform_device_unregister(info->pdev);
 }
 EXPORT_SYMBOL(unregister_dmac);

 static int __init dma_api_init(void)
 {
 	printk(KERN_NOTICE "DMA: Registering DMA API.\n");
 	return proc_create_single("dma", 0, NULL, dma_proc_show) ? 0 : -ENOMEM;
 }
 subsys_initcall(dma_api_init);

 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
 MODULE_DESCRIPTION("DMA API for SuperH");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* arch/sh/drivers/dma/dma-api.c
	*
	* SuperH-specific DMA management API
	*
	* Copyright (C) 2003, 2004, 2005 Paul Mundt
	*/
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/spinlock.h>
	#include <linux/proc_fs.h>
	#include <linux/seq_file.h>
	#include <linux/list.h>
	#include <linux/platform_device.h>
	#include <linux/mm.h>
	#include <linux/sched.h>
	#include <linux/slab.h>
	#include <asm/dma.h>

	DEFINE_SPINLOCK(dma_spin_lock);
	static LIST_HEAD(registered_dmac_list);

	struct dma_info *get_dma_info(unsigned int chan)
	{
	struct dma_info *info;

	/*
	* Look for each DMAC's range to determine who the owner of
	* the channel is.
	*/
	list_for_each_entry(info, &registered_dmac_list, list) {
	if ((chan < info->first_vchannel_nr) \|\|
	(chan >= info->first_vchannel_nr + info->nr_channels))
	continue;

	return info;
	}

	return NULL;
	}
	EXPORT_SYMBOL(get_dma_info);

	struct dma_info get_dma_info_by_name(const char dmac_name)
	{
	struct dma_info *info;

	list_for_each_entry(info, &registered_dmac_list, list) {
	if (dmac_name && (strcmp(dmac_name, info->name) != 0))
	continue;
	else
	return info;
	}

	return NULL;
	}
	EXPORT_SYMBOL(get_dma_info_by_name);

	static unsigned int get_nr_channels(void)
	{
	struct dma_info *info;
	unsigned int nr = 0;

	if (unlikely(list_empty(&registered_dmac_list)))
	return nr;

	list_for_each_entry(info, &registered_dmac_list, list)
	nr += info->nr_channels;

	return nr;
	}

	struct dma_channel *get_dma_channel(unsigned int chan)
	{
	struct dma_info *info = get_dma_info(chan);
	struct dma_channel *channel;
	int i;

	if (unlikely(!info))
	return ERR_PTR(-EINVAL);

	for (i = 0; i < info->nr_channels; i++) {
	channel = &info->channels[i];
	if (channel->vchan == chan)
	return channel;
	}

	return NULL;
	}
	EXPORT_SYMBOL(get_dma_channel);

	int get_dma_residue(unsigned int chan)
	{
	struct dma_info *info = get_dma_info(chan);
	struct dma_channel *channel = get_dma_channel(chan);

	if (info->ops->get_residue)
	return info->ops->get_residue(channel);

	return 0;
	}
	EXPORT_SYMBOL(get_dma_residue);

	static int search_cap(const char *haystack, const char needle)
	{
	const char **p;

	for (p = haystack; *p; p++)
	if (strcmp(*p, needle) == 0)
	return 1;

	return 0;
	}

	/**
	* request_dma_bycap - Allocate a DMA channel based on its capabilities
	* @dmac: List of DMA controllers to search
	* @caps: List of capabilities
	*
	* Search all channels of all DMA controllers to find a channel which
	* matches the requested capabilities. The result is the channel
	* number if a match is found, or %-ENODEV if no match is found.
	*
	* Note that not all DMA controllers export capabilities, in which
	* case they can never be allocated using this API, and so
	* request_dma() must be used specifying the channel number.
	*/
	int request_dma_bycap(const char dmac, const char caps, const char *dev_id)
	{
	unsigned int found = 0;
	struct dma_info *info;
	const char **p;
	int i;

	BUG_ON(!dmac \|\| !caps);

	list_for_each_entry(info, &registered_dmac_list, list)
	if (strcmp(*dmac, info->name) == 0) {
	found = 1;
	break;
	}

	if (!found)
	return -ENODEV;

	for (i = 0; i < info->nr_channels; i++) {
	struct dma_channel *channel = &info->channels[i];

	if (unlikely(!channel->caps))
	continue;

	for (p = caps; *p; p++) {
	if (!search_cap(channel->caps, *p))
	break;
	if (request_dma(channel->chan, dev_id) == 0)
	return channel->chan;
	}
	}

	return -EINVAL;
	}
	EXPORT_SYMBOL(request_dma_bycap);

	int dmac_search_free_channel(const char *dev_id)
	{
	struct dma_channel *channel = { 0 };
	struct dma_info *info = get_dma_info(0);
	int i;

	for (i = 0; i < info->nr_channels; i++) {
	channel = &info->channels[i];
	if (unlikely(!channel))
	return -ENODEV;

	if (atomic_read(&channel->busy) == 0)
	break;
	}

	if (info->ops->request) {
	int result = info->ops->request(channel);
	if (result)
	return result;

	atomic_set(&channel->busy, 1);
	return channel->chan;
	}

	return -ENOSYS;
	}

	int request_dma(unsigned int chan, const char *dev_id)
	{
	struct dma_channel *channel = { 0 };
	struct dma_info *info = get_dma_info(chan);
	int result;

	channel = get_dma_channel(chan);
	if (atomic_xchg(&channel->busy, 1))
	return -EBUSY;

	strscpy(channel->dev_id, dev_id, sizeof(channel->dev_id));

	if (info->ops->request) {
	result = info->ops->request(channel);
	if (result)
	atomic_set(&channel->busy, 0);

	return result;
	}

	return 0;
	}
	EXPORT_SYMBOL(request_dma);

	void free_dma(unsigned int chan)
	{
	struct dma_info *info = get_dma_info(chan);
	struct dma_channel *channel = get_dma_channel(chan);

	if (info->ops->free)
	info->ops->free(channel);

	atomic_set(&channel->busy, 0);
	}
	EXPORT_SYMBOL(free_dma);

	void dma_wait_for_completion(unsigned int chan)
	{
	struct dma_info *info = get_dma_info(chan);
	struct dma_channel *channel = get_dma_channel(chan);

	if (channel->flags & DMA_TEI_CAPABLE) {
	wait_event(channel->wait_queue,
	(info->ops->get_residue(channel) == 0));
	return;
	}

	while (info->ops->get_residue(channel))
	cpu_relax();
	}
	EXPORT_SYMBOL(dma_wait_for_completion);

	int register_chan_caps(const char dmac, struct dma_chan_caps caps)
	{
	struct dma_info *info;
	unsigned int found = 0;
	int i;

	list_for_each_entry(info, &registered_dmac_list, list)
	if (strcmp(dmac, info->name) == 0) {
	found = 1;
	break;
	}

	if (unlikely(!found))
	return -ENODEV;

	for (i = 0; i < info->nr_channels; i++, caps++) {
	struct dma_channel *channel;

	if ((info->first_channel_nr + i) != caps->ch_num)
	return -EINVAL;

	channel = &info->channels[i];
	channel->caps = caps->caplist;
	}

	return 0;
	}
	EXPORT_SYMBOL(register_chan_caps);

	void dma_configure_channel(unsigned int chan, unsigned long flags)
	{
	struct dma_info *info = get_dma_info(chan);
	struct dma_channel *channel = get_dma_channel(chan);

	if (info->ops->configure)
	info->ops->configure(channel, flags);
	}
	EXPORT_SYMBOL(dma_configure_channel);

	int dma_xfer(unsigned int chan, unsigned long from,
	unsigned long to, size_t size, unsigned int mode)
	{
	struct dma_info *info = get_dma_info(chan);
	struct dma_channel *channel = get_dma_channel(chan);

	channel->sar = from;
	channel->dar = to;
	channel->count = size;
	channel->mode = mode;

	return info->ops->xfer(channel);
	}
	EXPORT_SYMBOL(dma_xfer);

	int dma_extend(unsigned int chan, unsigned long op, void *param)
	{
	struct dma_info *info = get_dma_info(chan);
	struct dma_channel *channel = get_dma_channel(chan);

	if (info->ops->extend)
	return info->ops->extend(channel, op, param);

	return -ENOSYS;
	}
	EXPORT_SYMBOL(dma_extend);

	static int dma_proc_show(struct seq_file m, void v)
	{
	struct dma_info *info = v;

	if (list_empty(&registered_dmac_list))
	return 0;

	/*
	* Iterate over each registered DMAC
	*/
	list_for_each_entry(info, &registered_dmac_list, list) {
	int i;

	/*
	* Iterate over each channel
	*/
	for (i = 0; i < info->nr_channels; i++) {
	struct dma_channel *channel = info->channels + i;

	if (!(channel->flags & DMA_CONFIGURED))
	continue;

	seq_printf(m, "%2d: %14s %s\n", i,
	info->name, channel->dev_id);
	}
	}

	return 0;
	}

	int register_dmac(struct dma_info *info)
	{
	unsigned int total_channels, i;

	INIT_LIST_HEAD(&info->list);

	printk(KERN_INFO "DMA: Registering %s handler (%d channel%s).\n",
	info->name, info->nr_channels, info->nr_channels > 1 ? "s" : "");

	BUG_ON((info->flags & DMAC_CHANNELS_CONFIGURED) && !info->channels);

	info->pdev = platform_device_register_simple(info->name, -1,
	NULL, 0);
	if (IS_ERR(info->pdev))
	return PTR_ERR(info->pdev);

	/*
	* Don't touch pre-configured channels
	*/
	if (!(info->flags & DMAC_CHANNELS_CONFIGURED)) {
	unsigned int size;

	size = sizeof(struct dma_channel) * info->nr_channels;

	info->channels = kzalloc(size, GFP_KERNEL);
	if (!info->channels)
	return -ENOMEM;
	}

	total_channels = get_nr_channels();
	info->first_vchannel_nr = total_channels;
	for (i = 0; i < info->nr_channels; i++) {
	struct dma_channel *chan = &info->channels[i];

	atomic_set(&chan->busy, 0);

	chan->chan = info->first_channel_nr + i;
	chan->vchan = info->first_channel_nr + i + total_channels;

	memcpy(chan->dev_id, "Unused", 7);

	if (info->flags & DMAC_CHANNELS_TEI_CAPABLE)
	chan->flags \|= DMA_TEI_CAPABLE;

	init_waitqueue_head(&chan->wait_queue);
	dma_create_sysfs_files(chan, info);
	}

	list_add(&info->list, &registered_dmac_list);

	return 0;
	}
	EXPORT_SYMBOL(register_dmac);

	void unregister_dmac(struct dma_info *info)
	{
	unsigned int i;

	for (i = 0; i < info->nr_channels; i++)
	dma_remove_sysfs_files(info->channels + i, info);

	if (!(info->flags & DMAC_CHANNELS_CONFIGURED))
	kfree(info->channels);

	list_del(&info->list);
	platform_device_unregister(info->pdev);
	}
	EXPORT_SYMBOL(unregister_dmac);

	static int __init dma_api_init(void)
	{
	printk(KERN_NOTICE "DMA: Registering DMA API.\n");
	return proc_create_single("dma", 0, NULL, dma_proc_show) ? 0 : -ENOMEM;
	}
	subsys_initcall(dma_api_init);

	MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
	MODULE_DESCRIPTION("DMA API for SuperH");
	MODULE_LICENSE("GPL v2");