Re: [PATCH 20/20] [RFC] sh: dma: Remove unused functionality

[John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>]

Hi Geert,

On Wed, 2024-05-01 at 11:12 +0200, John Paul Adrian Glaubitz wrote:
> Hi Geert,
> 
> On Fri, 2024-03-01 at 22:02 +0100, Geert Uytterhoeven wrote:
> > dma_extend(), get_dma_info_by_name(), register_chan_caps(), and
> > request_dma_bycap() are unused.  Remove them, and all related code.
> > 
> > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> > ---
> >  arch/sh/drivers/dma/dma-api.c | 116 ----------------------------------
> >  arch/sh/include/asm/dma.h     |   7 --
> >  2 files changed, 123 deletions(-)
> > 
> > diff --git a/arch/sh/drivers/dma/dma-api.c b/arch/sh/drivers/dma/dma-api.c
> > index f49097fa634c36d4..87e5a892887360f5 100644
> > --- a/arch/sh/drivers/dma/dma-api.c
> > +++ b/arch/sh/drivers/dma/dma-api.c
> > @@ -41,21 +41,6 @@ struct dma_info *get_dma_info(unsigned int chan)
> >  }
> >  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;
> > @@ -101,66 +86,6 @@ int get_dma_residue(unsigned int chan)
> >  }
> >  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 request_dma(unsigned int chan, const char *dev_id)
> >  {
> >  	struct dma_channel *channel = { 0 };
> > @@ -213,35 +138,6 @@ void dma_wait_for_completion(unsigned int chan)
> >  }
> >  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);
> > @@ -267,18 +163,6 @@ int dma_xfer(unsigned int chan, unsigned long from,
> >  }
> >  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;
> > diff --git a/arch/sh/include/asm/dma.h b/arch/sh/include/asm/dma.h
> > index c8bee3f985a29393..6b6d409956d17f09 100644
> > --- a/arch/sh/include/asm/dma.h
> > +++ b/arch/sh/include/asm/dma.h
> > @@ -56,7 +56,6 @@ struct dma_ops {
> >  	int (*get_residue)(struct dma_channel *chan);
> >  	int (*xfer)(struct dma_channel *chan);
> >  	int (*configure)(struct dma_channel *chan, unsigned long flags);
> > -	int (*extend)(struct dma_channel *chan, unsigned long op, void *param);
> >  };
> >  
> >  struct dma_channel {
> > @@ -118,8 +117,6 @@ 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 get_dma_residue(unsigned int chan);
> >  extern struct dma_info *get_dma_info(unsigned int chan);
> >  extern struct dma_channel *get_dma_channel(unsigned int chan);
> > @@ -128,10 +125,6 @@ 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);
> >  
> >  /* arch/sh/drivers/dma/dma-sysfs.c */
> >  extern int dma_create_sysfs_files(struct dma_channel *, struct dma_info *);
> 
> I assume we could re-add these again in case we need them, but it would be good
> if Yoshinori could comment on whether we should keep these functions or not.

I was wondering: Could there be any userland tools using these DMA functions?

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
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