summaryrefslogtreecommitdiffstats
path: root/arch/sh/drivers/dma/dma-api.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/sh/drivers/dma/dma-api.c')
-rw-r--r--arch/sh/drivers/dma/dma-api.c417
1 files changed, 417 insertions, 0 deletions
diff --git a/arch/sh/drivers/dma/dma-api.c b/arch/sh/drivers/dma/dma-api.c
new file mode 100644
index 0000000000..89cd4a3b4c
--- /dev/null
+++ b/arch/sh/drivers/dma/dma-api.c
@@ -0,0 +1,417 @@
+// 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");
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-05 13:28:56 +0000