sh: dma-api channel capability extensions.
This extends the SH DMA API for allowing handling of DMA channels based off of their respective capabilities. A couple of functions are added to the existing API, the core bits are register_chan_caps() for registering channel capabilities, and request_dma_bycap() for fetching a channel dynamically based off of a capability set. Signed-off-by: Mark Glaisher <mark.glaisher@st.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Mark Glaisher
Paul Mundt
parent
e803aaf63a
commit
db9b99d461
2 changed files with 225 additions and 103 deletions
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@ -11,61 +11,27 @@
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/spinlock.h>
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#include <linux/proc_fs.h>
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#include <linux/list.h>
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#include <linux/platform_device.h>
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#include <linux/mm.h>
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#include <asm/dma.h>
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DEFINE_SPINLOCK(dma_spin_lock);
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static LIST_HEAD(registered_dmac_list);
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/*
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* A brief note about the reasons for this API as it stands.
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*
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* For starters, the old ISA DMA API didn't work for us for a number of
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* reasons, for one, the vast majority of channels on the SH DMAC are
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* dual-address mode only, and both the new and the old DMA APIs are after the
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* concept of managing a DMA buffer, which doesn't overly fit this model very
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* well. In addition to which, the new API is largely geared at IOMMUs and
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* GARTs, and doesn't even support the channel notion very well.
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*
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* The other thing that's a marginal issue, is the sheer number of random DMA
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* engines that are present (ie, in boards like the Dreamcast), some of which
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* cascade off of the SH DMAC, and others do not. As such, there was a real
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* need for a scalable subsystem that could deal with both single and
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* dual-address mode usage, in addition to interoperating with cascaded DMACs.
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*
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* There really isn't any reason why this needs to be SH specific, though I'm
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* not aware of too many other processors (with the exception of some MIPS)
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* that have the same concept of a dual address mode, or any real desire to
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* actually make use of the DMAC even if such a subsystem were exposed
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* elsewhere.
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*
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* The idea for this was derived from the ARM port, which acted as an excellent
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* reference when trying to address these issues.
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*
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* It should also be noted that the decision to add Yet Another DMA API(tm) to
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* the kernel wasn't made easily, and was only decided upon after conferring
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* with jejb with regards to the state of the old and new APIs as they applied
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* to these circumstances. Philip Blundell was also a great help in figuring
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* out some single-address mode DMA semantics that were otherwise rather
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* confusing.
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*/
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struct dma_info *get_dma_info(unsigned int chan)
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{
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struct dma_info *info;
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unsigned int total = 0;
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/*
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* Look for each DMAC's range to determine who the owner of
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* the channel is.
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*/
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list_for_each_entry(info, ®istered_dmac_list, list) {
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total += info->nr_channels;
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if (chan > total)
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if ((chan < info->first_channel_nr) ||
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(chan >= info->first_channel_nr + info->nr_channels))
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continue;
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return info;
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@ -73,6 +39,22 @@ struct dma_info *get_dma_info(unsigned int chan)
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return NULL;
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}
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EXPORT_SYMBOL(get_dma_info);
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struct dma_info *get_dma_info_by_name(const char *dmac_name)
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{
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struct dma_info *info;
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list_for_each_entry(info, ®istered_dmac_list, list) {
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if (dmac_name && (strcmp(dmac_name, info->name) != 0))
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continue;
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else
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return info;
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}
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return NULL;
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}
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EXPORT_SYMBOL(get_dma_info_by_name);
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static unsigned int get_nr_channels(void)
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{
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@ -91,63 +73,161 @@ static unsigned int get_nr_channels(void)
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struct dma_channel *get_dma_channel(unsigned int chan)
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{
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struct dma_info *info = get_dma_info(chan);
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struct dma_channel *channel;
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int i;
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if (!info)
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if (unlikely(!info))
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return ERR_PTR(-EINVAL);
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return info->channels + chan;
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for (i = 0; i < info->nr_channels; i++) {
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channel = &info->channels[i];
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if (channel->chan == chan)
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return channel;
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}
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return NULL;
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}
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EXPORT_SYMBOL(get_dma_channel);
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int get_dma_residue(unsigned int chan)
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{
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struct dma_info *info = get_dma_info(chan);
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struct dma_channel *channel = &info->channels[chan];
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struct dma_channel *channel = get_dma_channel(chan);
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if (info->ops->get_residue)
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return info->ops->get_residue(channel);
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return 0;
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}
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EXPORT_SYMBOL(get_dma_residue);
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int request_dma(unsigned int chan, const char *dev_id)
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static int search_cap(const char **haystack, const char *needle)
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{
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struct dma_info *info = get_dma_info(chan);
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struct dma_channel *channel = &info->channels[chan];
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const char **p;
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down(&channel->sem);
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if (!info->ops || chan >= MAX_DMA_CHANNELS) {
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up(&channel->sem);
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return -EINVAL;
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}
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atomic_set(&channel->busy, 1);
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strlcpy(channel->dev_id, dev_id, sizeof(channel->dev_id));
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up(&channel->sem);
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if (info->ops->request)
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return info->ops->request(channel);
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for (p = haystack; *p; p++)
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if (strcmp(*p, needle) == 0)
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return 1;
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return 0;
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}
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/**
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* request_dma_bycap - Allocate a DMA channel based on its capabilities
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* @dmac: List of DMA controllers to search
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* @caps: List of capabilites
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*
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* Search all channels of all DMA controllers to find a channel which
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* matches the requested capabilities. The result is the channel
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* number if a match is found, or %-ENODEV if no match is found.
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*
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* Note that not all DMA controllers export capabilities, in which
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* case they can never be allocated using this API, and so
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* request_dma() must be used specifying the channel number.
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*/
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int request_dma_bycap(const char **dmac, const char **caps, const char *dev_id)
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{
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unsigned int found = 0;
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struct dma_info *info;
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const char **p;
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int i;
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BUG_ON(!dmac || !caps);
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list_for_each_entry(info, ®istered_dmac_list, list)
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if (strcmp(*dmac, info->name) == 0) {
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found = 1;
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break;
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}
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if (!found)
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return -ENODEV;
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for (i = 0; i < info->nr_channels; i++) {
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struct dma_channel *channel = &info->channels[i];
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if (unlikely(!channel->caps))
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continue;
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for (p = caps; *p; p++) {
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if (!search_cap(channel->caps, *p))
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break;
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if (request_dma(channel->chan, dev_id) == 0)
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return channel->chan;
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}
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}
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return -EINVAL;
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}
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EXPORT_SYMBOL(request_dma_bycap);
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int dmac_search_free_channel(const char *dev_id)
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{
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struct dma_channel *channel = { 0 };
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struct dma_info *info = get_dma_info(0);
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int i;
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for (i = 0; i < info->nr_channels; i++) {
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channel = &info->channels[i];
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if (unlikely(!channel))
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return -ENODEV;
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if (atomic_read(&channel->busy) == 0)
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break;
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}
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if (info->ops->request) {
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int result = info->ops->request(channel);
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if (result)
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return result;
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atomic_set(&channel->busy, 1);
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return channel->chan;
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}
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return -ENOSYS;
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}
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int request_dma(unsigned int chan, const char *dev_id)
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{
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struct dma_channel *channel = { 0 };
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struct dma_info *info = get_dma_info(chan);
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int result;
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channel = get_dma_channel(chan);
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if (atomic_xchg(&channel->busy, 1))
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return -EBUSY;
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strlcpy(channel->dev_id, dev_id, sizeof(channel->dev_id));
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if (info->ops->request) {
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result = info->ops->request(channel);
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if (result)
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atomic_set(&channel->busy, 0);
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return result;
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}
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return 0;
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}
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EXPORT_SYMBOL(request_dma);
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void free_dma(unsigned int chan)
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{
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struct dma_info *info = get_dma_info(chan);
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struct dma_channel *channel = &info->channels[chan];
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struct dma_channel *channel = get_dma_channel(chan);
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if (info->ops->free)
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info->ops->free(channel);
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atomic_set(&channel->busy, 0);
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}
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EXPORT_SYMBOL(free_dma);
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void dma_wait_for_completion(unsigned int chan)
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{
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struct dma_info *info = get_dma_info(chan);
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struct dma_channel *channel = &info->channels[chan];
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struct dma_channel *channel = get_dma_channel(chan);
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if (channel->flags & DMA_TEI_CAPABLE) {
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wait_event(channel->wait_queue,
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@ -158,21 +238,52 @@ void dma_wait_for_completion(unsigned int chan)
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while (info->ops->get_residue(channel))
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cpu_relax();
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}
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EXPORT_SYMBOL(dma_wait_for_completion);
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int register_chan_caps(const char *dmac, struct dma_chan_caps *caps)
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{
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struct dma_info *info;
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unsigned int found = 0;
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int i;
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list_for_each_entry(info, ®istered_dmac_list, list)
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if (strcmp(dmac, info->name) == 0) {
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found = 1;
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break;
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}
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if (unlikely(!found))
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return -ENODEV;
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for (i = 0; i < info->nr_channels; i++, caps++) {
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struct dma_channel *channel;
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if ((info->first_channel_nr + i) != caps->ch_num)
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return -EINVAL;
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channel = &info->channels[i];
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channel->caps = caps->caplist;
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}
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return 0;
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}
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EXPORT_SYMBOL(register_chan_caps);
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void dma_configure_channel(unsigned int chan, unsigned long flags)
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{
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struct dma_info *info = get_dma_info(chan);
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struct dma_channel *channel = &info->channels[chan];
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struct dma_channel *channel = get_dma_channel(chan);
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if (info->ops->configure)
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info->ops->configure(channel, flags);
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}
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EXPORT_SYMBOL(dma_configure_channel);
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int dma_xfer(unsigned int chan, unsigned long from,
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unsigned long to, size_t size, unsigned int mode)
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{
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struct dma_info *info = get_dma_info(chan);
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struct dma_channel *channel = &info->channels[chan];
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struct dma_channel *channel = get_dma_channel(chan);
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channel->sar = from;
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channel->dar = to;
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@ -181,8 +292,20 @@ int dma_xfer(unsigned int chan, unsigned long from,
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return info->ops->xfer(channel);
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}
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EXPORT_SYMBOL(dma_xfer);
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int dma_extend(unsigned int chan, unsigned long op, void *param)
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{
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struct dma_info *info = get_dma_info(chan);
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struct dma_channel *channel = get_dma_channel(chan);
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if (info->ops->extend)
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return info->ops->extend(channel, op, param);
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return -ENOSYS;
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}
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EXPORT_SYMBOL(dma_extend);
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#ifdef CONFIG_PROC_FS
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static int dma_read_proc(char *buf, char **start, off_t off,
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int len, int *eof, void *data)
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{
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@ -214,8 +337,6 @@ static int dma_read_proc(char *buf, char **start, off_t off,
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return p - buf;
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}
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#endif
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int register_dmac(struct dma_info *info)
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{
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@ -224,8 +345,7 @@ int register_dmac(struct dma_info *info)
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INIT_LIST_HEAD(&info->list);
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printk(KERN_INFO "DMA: Registering %s handler (%d channel%s).\n",
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info->name, info->nr_channels,
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info->nr_channels > 1 ? "s" : "");
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info->name, info->nr_channels, info->nr_channels > 1 ? "s" : "");
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BUG_ON((info->flags & DMAC_CHANNELS_CONFIGURED) && !info->channels);
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@ -242,28 +362,26 @@ int register_dmac(struct dma_info *info)
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size = sizeof(struct dma_channel) * info->nr_channels;
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info->channels = kmalloc(size, GFP_KERNEL);
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info->channels = kzalloc(size, GFP_KERNEL);
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if (!info->channels)
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return -ENOMEM;
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memset(info->channels, 0, size);
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}
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total_channels = get_nr_channels();
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for (i = 0; i < info->nr_channels; i++) {
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struct dma_channel *chan = info->channels + i;
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struct dma_channel *chan = &info->channels[i];
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chan->chan = i;
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chan->vchan = i + total_channels;
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atomic_set(&chan->busy, 0);
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chan->chan = info->first_channel_nr + i;
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chan->vchan = info->first_channel_nr + i + total_channels;
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memcpy(chan->dev_id, "Unused", 7);
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if (info->flags & DMAC_CHANNELS_TEI_CAPABLE)
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chan->flags |= DMA_TEI_CAPABLE;
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init_MUTEX(&chan->sem);
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init_waitqueue_head(&chan->wait_queue);
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dma_create_sysfs_files(chan, info);
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}
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@ -271,6 +389,7 @@ int register_dmac(struct dma_info *info)
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return 0;
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}
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EXPORT_SYMBOL(register_dmac);
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void unregister_dmac(struct dma_info *info)
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{
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@ -285,31 +404,16 @@ void unregister_dmac(struct dma_info *info)
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list_del(&info->list);
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platform_device_unregister(info->pdev);
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}
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EXPORT_SYMBOL(unregister_dmac);
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static int __init dma_api_init(void)
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{
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printk("DMA: Registering DMA API.\n");
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#ifdef CONFIG_PROC_FS
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printk(KERN_NOTICE "DMA: Registering DMA API.\n");
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create_proc_read_entry("dma", 0, 0, dma_read_proc, 0);
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#endif
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return 0;
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}
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subsys_initcall(dma_api_init);
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MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
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MODULE_DESCRIPTION("DMA API for SuperH");
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MODULE_LICENSE("GPL");
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EXPORT_SYMBOL(request_dma);
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EXPORT_SYMBOL(free_dma);
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EXPORT_SYMBOL(register_dmac);
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EXPORT_SYMBOL(get_dma_residue);
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EXPORT_SYMBOL(get_dma_info);
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EXPORT_SYMBOL(get_dma_channel);
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EXPORT_SYMBOL(dma_xfer);
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EXPORT_SYMBOL(dma_wait_for_completion);
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EXPORT_SYMBOL(dma_configure_channel);
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@ -14,9 +14,7 @@
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#include <linux/spinlock.h>
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#include <linux/wait.h>
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#include <linux/sysdev.h>
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#include <linux/device.h>
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#include <asm/cpu/dma.h>
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#include <asm/semaphore.h>
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/* The maximum address that we can perform a DMA transfer to on this platform */
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/* Don't define MAX_DMA_ADDRESS; it's useless on the SuperH and any
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@ -46,16 +44,21 @@
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* DMAC (dma_info) flags
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*/
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enum {
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DMAC_CHANNELS_CONFIGURED = 0x00,
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DMAC_CHANNELS_TEI_CAPABLE = 0x01,
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DMAC_CHANNELS_CONFIGURED = 0x01,
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DMAC_CHANNELS_TEI_CAPABLE = 0x02, /* Transfer end interrupt */
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};
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/*
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* DMA channel capabilities / flags
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*/
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enum {
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DMA_TEI_CAPABLE = 0x01,
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DMA_CONFIGURED = 0x02,
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DMA_CONFIGURED = 0x01,
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/*
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* Transfer end interrupt, inherited from DMAC.
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* wait_queue used in dma_wait_for_completion.
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*/
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DMA_TEI_CAPABLE = 0x02,
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};
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extern spinlock_t dma_spin_lock;
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@ -68,28 +71,31 @@ struct dma_ops {
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||||
int (*get_residue)(struct dma_channel *chan);
|
||||
int (*xfer)(struct dma_channel *chan);
|
||||
void (*configure)(struct dma_channel *chan, unsigned long flags);
|
||||
int (*configure)(struct dma_channel *chan, unsigned long flags);
|
||||
int (*extend)(struct dma_channel *chan, unsigned long op, void *param);
|
||||
};
|
||||
|
||||
struct dma_channel {
|
||||
char dev_id[16];
|
||||
char dev_id[16]; /* unique name per DMAC of channel */
|
||||
|
||||
unsigned int chan; /* Physical channel number */
|
||||
unsigned int chan; /* DMAC channel number */
|
||||
unsigned int vchan; /* Virtual channel number */
|
||||
|
||||
unsigned int mode;
|
||||
unsigned int count;
|
||||
|
||||
unsigned long sar;
|
||||
unsigned long dar;
|
||||
|
||||
const char **caps;
|
||||
|
||||
unsigned long flags;
|
||||
atomic_t busy;
|
||||
|
||||
struct semaphore sem;
|
||||
wait_queue_head_t wait_queue;
|
||||
|
||||
struct sys_device dev;
|
||||
char *name;
|
||||
void *priv_data;
|
||||
};
|
||||
|
||||
struct dma_info {
|
||||
|
|
@ -103,6 +109,12 @@ struct dma_info {
|
|||
struct dma_channel *channels;
|
||||
|
||||
struct list_head list;
|
||||
int first_channel_nr;
|
||||
};
|
||||
|
||||
struct dma_chan_caps {
|
||||
int ch_num;
|
||||
const char **caplist;
|
||||
};
|
||||
|
||||
#define to_dma_channel(channel) container_of(channel, struct dma_channel, dev)
|
||||
|
|
@ -121,6 +133,8 @@ extern int dma_xfer(unsigned int chan, unsigned long from,
|
|||
#define dma_read_page(chan, from, to) \
|
||||
dma_read(chan, from, to, PAGE_SIZE)
|
||||
|
||||
extern int request_dma_bycap(const char **dmac, const char **caps,
|
||||
const char *dev_id);
|
||||
extern int request_dma(unsigned int chan, const char *dev_id);
|
||||
extern void free_dma(unsigned int chan);
|
||||
extern int get_dma_residue(unsigned int chan);
|
||||
|
|
@ -131,6 +145,10 @@ extern void dma_configure_channel(unsigned int chan, unsigned long flags);
|
|||
|
||||
extern int register_dmac(struct dma_info *info);
|
||||
extern void unregister_dmac(struct dma_info *info);
|
||||
extern struct dma_info *get_dma_info_by_name(const char *dmac_name);
|
||||
|
||||
extern int dma_extend(unsigned int chan, unsigned long op, void *param);
|
||||
extern int register_chan_caps(const char *dmac, struct dma_chan_caps *capslist);
|
||||
|
||||
#ifdef CONFIG_SYSFS
|
||||
/* arch/sh/drivers/dma/dma-sysfs.c */
|
||||
|
|
|
|||
Loading…
Reference in a new issue