Along with the conversion to PCM copy ops, use the iov_iter for the
pointer to be passed to the dmaengine process callback, too.  It
avoids the direct reference of iter_iov_addr(), and it can potentially
help for the drivers to access memory properly (although both atmel
and stm drivers don't use the given buffer address at all for now).
Reviewed-by: Mark Brown <broonie@kernel.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Claudiu Beznea <claudiu.beznea@microchip.com>
Cc: Olivier Moysan <olivier.moysan@foss.st.com>
Cc: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Link: https://lore.kernel.org/r/20230815190136.8987-23-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
                        struct snd_pcm_substream *substream);
        int (*process)(struct snd_pcm_substream *substream,
                       int channel, unsigned long hwoff,
-                      void *buf, unsigned long bytes);
+                      struct iov_iter *buf, unsigned long bytes);
        dma_filter_fn compat_filter_fn;
        struct device *dma_dev;
        const char *chan_names[SNDRV_PCM_STREAM_LAST + 1];
 
 /* used to clean the channel index found on RHR's MSB */
 static int mchp_pdmc_process(struct snd_pcm_substream *substream,
                             int channel, unsigned long hwoff,
-                            void *buf, unsigned long bytes)
+                            struct iov_iter *buf, unsigned long bytes)
 {
        struct snd_pcm_runtime *runtime = substream->runtime;
        u8 *dma_ptr = runtime->dma_area + hwoff +
 
        struct dmaengine_pcm *pcm = soc_component_to_pcm(component);
        int (*process)(struct snd_pcm_substream *substream,
                       int channel, unsigned long hwoff,
-                      void *buf, unsigned long bytes) = pcm->config->process;
+                      struct iov_iter *buf, unsigned long bytes) = pcm->config->process;
        bool is_playback = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
        void *dma_ptr = runtime->dma_area + hwoff +
                        channel * (runtime->dma_bytes / runtime->channels);
-       void *ptr = (void __force *)iter_iov_addr(buf);
 
        if (is_playback)
                if (copy_from_iter(dma_ptr, bytes, buf) != bytes)
                        return -EFAULT;
 
        if (process) {
-               int ret = process(substream, channel, hwoff, ptr, bytes);
+               int ret = process(substream, channel, hwoff, buf, bytes);
                if (ret < 0)
                        return ret;
        }
 
 
 static int stm32_sai_pcm_process_spdif(struct snd_pcm_substream *substream,
                                       int channel, unsigned long hwoff,
-                                      void *buf, unsigned long bytes)
+                                      struct iov_iter *buf, unsigned long bytes)
 {
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);