X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Fsh%2Fdrivers%2Fdma%2Fdma-api.c;h=e062067edd243fac0e2bdacd12ee3fdf1600fdfc;hb=97bf2856c6014879bd04983a3e9dfcdac1e7fe85;hp=f8b352d4b091a3e9cbb095d5ad5947a61dde78f1;hpb=5273a3df6485dc2ad6aa7ddd441b9a21970f003b;p=linux-2.6.git diff --git a/arch/sh/drivers/dma/dma-api.c b/arch/sh/drivers/dma/dma-api.c index f8b352d4b..e062067ed 100644 --- a/arch/sh/drivers/dma/dma-api.c +++ b/arch/sh/drivers/dma/dma-api.c @@ -3,197 +3,417 @@ * * SuperH-specific DMA management API * - * Copyright (C) 2003 Paul Mundt + * Copyright (C) 2003, 2004, 2005 Paul Mundt * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. - */ + */ #include #include -#include #include #include +#include +#include +#include #include -struct dma_info dma_info[MAX_DMA_CHANNELS] = { { 0, } }; -spinlock_t dma_spin_lock = SPIN_LOCK_UNLOCKED; - -/* - * A brief note about the reasons for this API as it stands. - * - * For starters, the old ISA DMA API didn't work for us for a number of - * reasons, for one, the vast majority of channels on the SH DMAC are - * dual-address mode only, and both the new and the old DMA APIs are after the - * concept of managing a DMA buffer, which doesn't overly fit this model very - * well. In addition to which, the new API is largely geared at IOMMUs and - * GARTs, and doesn't even support the channel notion very well. - * - * The other thing that's a marginal issue, is the sheer number of random DMA - * engines that are present (ie, in boards like the Dreamcast), some of which - * cascade off of the SH DMAC, and others do not. As such, there was a real - * need for a scalable subsystem that could deal with both single and - * dual-address mode usage, in addition to interoperating with cascaded DMACs. - * - * There really isn't any reason why this needs to be SH specific, though I'm - * not aware of too many other processors (with the exception of some MIPS) - * that have the same concept of a dual address mode, or any real desire to - * actually make use of the DMAC even if such a subsystem were exposed - * elsewhere. - * - * The idea for this was derived from the ARM port, which acted as an excellent - * reference when trying to address these issues. - * - * It should also be noted that the decision to add Yet Another DMA API(tm) to - * the kernel wasn't made easily, and was only decided upon after conferring - * with jejb with regards to the state of the old and new APIs as they applied - * to these circumstances. Philip Blundell was also a great help in figuring - * out some single-address mode DMA semantics that were otherwise rather - * confusing. - */ +DEFINE_SPINLOCK(dma_spin_lock); +static LIST_HEAD(registered_dmac_list); struct dma_info *get_dma_info(unsigned int chan) { - return dma_info + 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, ®istered_dmac_list, list) { + if ((chan < info->first_channel_nr) || + (chan >= info->first_channel_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, ®istered_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(®istered_dmac_list))) + return nr; + + list_for_each_entry(info, ®istered_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->chan == 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(info); - + 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 capabilites + * + * 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, ®istered_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; - down(&info->sem); + channel = get_dma_channel(chan); + if (atomic_xchg(&channel->busy, 1)) + return -EBUSY; - if (!info->ops || chan >= MAX_DMA_CHANNELS) { - up(&info->sem); - return -EINVAL; - } - - atomic_set(&info->busy, 1); + strlcpy(channel->dev_id, dev_id, sizeof(channel->dev_id)); - info->dev_id = dev_id; + if (info->ops->request) { + result = info->ops->request(channel); + if (result) + atomic_set(&channel->busy, 0); - up(&info->sem); + return result; + } - if (info->ops->request) - return info->ops->request(info); - 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(info); - - atomic_set(&info->busy, 0); + 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 (info->tei_capable) { - wait_event(info->wait_queue, (info->ops->get_residue(info) == 0)); + if (channel->flags & DMA_TEI_CAPABLE) { + wait_event(channel->wait_queue, + (info->ops->get_residue(channel) == 0)); return; } - while (info->ops->get_residue(info)) + 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, ®istered_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(info, flags); + 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); - info->sar = from; - info->dar = to; - info->count = size; - info->mode = mode; + channel->sar = from; + channel->dar = to; + channel->count = size; + channel->mode = mode; - return info->ops->xfer(info); + 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); -#ifdef CONFIG_PROC_FS static int dma_read_proc(char *buf, char **start, off_t off, int len, int *eof, void *data) { struct dma_info *info; char *p = buf; - int i; - for (i = 0, info = dma_info; i < MAX_DMA_CHANNELS; i++, info++) { - if (!atomic_read(&info->busy)) - continue; + if (list_empty(®istered_dmac_list)) + return 0; + + /* + * Iterate over each registered DMAC + */ + list_for_each_entry(info, ®istered_dmac_list, list) { + int i; + + /* + * Iterate over each channel + */ + for (i = 0; i < info->nr_channels; i++) { + struct dma_channel *channel = info->channels + i; - p += sprintf(p, "%2d: %14s %s\n", i, - info->ops->name, info->dev_id); + if (!(channel->flags & DMA_CONFIGURED)) + continue; + + p += sprintf(p, "%2d: %14s %s\n", i, + info->name, channel->dev_id); + } } return p - buf; } -#endif -int __init register_dmac(struct dma_ops *ops) +int register_dmac(struct dma_info *info) { - int i; + unsigned int total_channels, i; - printk("DMA: Registering %s handler.\n", ops->name); + INIT_LIST_HEAD(&info->list); - for (i = 0; i < MAX_DMA_CHANNELS; i++) { - struct dma_info *info = get_dma_info(i); + printk(KERN_INFO "DMA: Registering %s handler (%d channel%s).\n", + info->name, info->nr_channels, info->nr_channels > 1 ? "s" : ""); - info->chan = i; + BUG_ON((info->flags & DMAC_CHANNELS_CONFIGURED) && !info->channels); - init_MUTEX(&info->sem); - init_waitqueue_head(&info->wait_queue); + info->pdev = platform_device_register_simple((char *)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(); + 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, ®istered_dmac_list); + return 0; } +EXPORT_SYMBOL(register_dmac); -static int __init dma_api_init(void) +void unregister_dmac(struct dma_info *info) { - printk("DMA: Registering DMA API.\n"); + unsigned int i; -#ifdef CONFIG_PROC_FS - create_proc_read_entry("dma", 0, 0, dma_read_proc, 0); -#endif + for (i = 0; i < info->nr_channels; i++) + dma_remove_sysfs_files(info->channels + i, info); - return 0; + 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"); + create_proc_read_entry("dma", 0, 0, dma_read_proc, 0); + return 0; +} subsys_initcall(dma_api_init); MODULE_AUTHOR("Paul Mundt "); MODULE_DESCRIPTION("DMA API for SuperH"); MODULE_LICENSE("GPL"); - -EXPORT_SYMBOL(request_dma); -EXPORT_SYMBOL(free_dma); -EXPORT_SYMBOL(get_dma_residue); -EXPORT_SYMBOL(get_dma_info); -EXPORT_SYMBOL(dma_xfer); -EXPORT_SYMBOL(dma_wait_for_completion); -EXPORT_SYMBOL(dma_configure_channel); -