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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /arch/sh/drivers/dma/dma-api.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/sh/drivers/dma/dma-api.c')
-rw-r--r-- | arch/sh/drivers/dma/dma-api.c | 417 |
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 000000000..ab9170494 --- /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, ®istered_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, ®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->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, ®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; + + channel = get_dma_channel(chan); + if (atomic_xchg(&channel->busy, 1)) + return -EBUSY; + + strlcpy(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, ®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(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(®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; + + 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, ®istered_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"); |