433 lines
9.4 KiB
C
433 lines
9.4 KiB
C
/*
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* arch/sh/drivers/dma/dma-api.c
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*
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* SuperH-specific DMA management API
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*
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* Copyright (C) 2003, 2004, 2005 Paul Mundt
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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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/spinlock.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.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 <linux/sched.h>
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#include <linux/slab.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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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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/*
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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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if ((chan < info->first_vchannel_nr) ||
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(chan >= info->first_vchannel_nr + info->nr_channels))
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continue;
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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);
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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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struct dma_info *info;
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unsigned int nr = 0;
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if (unlikely(list_empty(®istered_dmac_list)))
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return nr;
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list_for_each_entry(info, ®istered_dmac_list, list)
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nr += info->nr_channels;
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return nr;
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}
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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 (unlikely(!info))
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return ERR_PTR(-EINVAL);
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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->vchan == 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 = 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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static int search_cap(const char **haystack, const char *needle)
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{
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const char **p;
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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 capabilities
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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 = 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 = 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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(info->ops->get_residue(channel) == 0));
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return;
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}
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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 = 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 = get_dma_channel(chan);
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channel->sar = from;
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channel->dar = to;
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channel->count = size;
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channel->mode = mode;
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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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static int dma_proc_show(struct seq_file *m, void *v)
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{
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struct dma_info *info = v;
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if (list_empty(®istered_dmac_list))
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return 0;
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/*
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* Iterate over each registered DMAC
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*/
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list_for_each_entry(info, ®istered_dmac_list, list) {
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int i;
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/*
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* Iterate over each channel
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*/
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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 (!(channel->flags & DMA_CONFIGURED))
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continue;
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seq_printf(m, "%2d: %14s %s\n", i,
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info->name, channel->dev_id);
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}
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}
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return 0;
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}
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static int dma_proc_open(struct inode *inode, struct file *file)
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{
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return single_open(file, dma_proc_show, NULL);
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}
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static const struct file_operations dma_proc_fops = {
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.open = dma_proc_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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int register_dmac(struct dma_info *info)
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{
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unsigned int total_channels, i;
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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, info->nr_channels > 1 ? "s" : "");
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BUG_ON((info->flags & DMAC_CHANNELS_CONFIGURED) && !info->channels);
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info->pdev = platform_device_register_simple(info->name, -1,
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NULL, 0);
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if (IS_ERR(info->pdev))
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return PTR_ERR(info->pdev);
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/*
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* Don't touch pre-configured channels
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*/
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if (!(info->flags & DMAC_CHANNELS_CONFIGURED)) {
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unsigned int size;
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size = sizeof(struct dma_channel) * info->nr_channels;
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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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}
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total_channels = get_nr_channels();
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info->first_vchannel_nr = total_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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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_waitqueue_head(&chan->wait_queue);
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dma_create_sysfs_files(chan, info);
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}
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list_add(&info->list, ®istered_dmac_list);
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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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unsigned int i;
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for (i = 0; i < info->nr_channels; i++)
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dma_remove_sysfs_files(info->channels + i, info);
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if (!(info->flags & DMAC_CHANNELS_CONFIGURED))
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kfree(info->channels);
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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(KERN_NOTICE "DMA: Registering DMA API.\n");
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return proc_create("dma", 0, NULL, &dma_proc_fops) ? 0 : -ENOMEM;
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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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