// SPDX-License-Identifier: GPL-2.0-only
/*
 * amdtp-ff.c - a part of driver for RME Fireface series
 *
 * Copyright (c) 2015-2017 Takashi Sakamoto
 */

#include <sound/pcm.h>
#include "ff.h"

struct amdtp_ff {
        unsigned int pcm_channels;
};

int amdtp_ff_set_parameters(struct amdtp_stream *s, unsigned int rate,
                            unsigned int pcm_channels)
{
        struct amdtp_ff *p = s->protocol;
        unsigned int data_channels;

        if (amdtp_stream_running(s))
                return -EBUSY;

        p->pcm_channels = pcm_channels;
        data_channels = pcm_channels;

        return amdtp_stream_set_parameters(s, rate, data_channels, 1);
}

static void write_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
                          __le32 *buffer, unsigned int frames,
                          unsigned int pcm_frames)
{
        struct amdtp_ff *p = s->protocol;
        unsigned int channels = p->pcm_channels;
        struct snd_pcm_runtime *runtime = pcm->runtime;
        unsigned int pcm_buffer_pointer;
        int remaining_frames;
        const u32 *src;
        int i, c;

        pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames;
        pcm_buffer_pointer %= runtime->buffer_size;

        src = (void *)runtime->dma_area +
                                frames_to_bytes(runtime, pcm_buffer_pointer);
        remaining_frames = runtime->buffer_size - pcm_buffer_pointer;

        for (i = 0; i < frames; ++i) {
                for (c = 0; c < channels; ++c) {
                        buffer[c] = cpu_to_le32(*src);
                        src++;
                }
                buffer += s->data_block_quadlets;
                if (--remaining_frames == 0)
                        src = (void *)runtime->dma_area;
        }
}

static void read_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
                         __le32 *buffer, unsigned int frames,
                         unsigned int pcm_frames)
{
        struct amdtp_ff *p = s->protocol;
        unsigned int channels = p->pcm_channels;
        struct snd_pcm_runtime *runtime = pcm->runtime;
        unsigned int pcm_buffer_pointer;
        int remaining_frames;
        u32 *dst;
        int i, c;

        pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames;
        pcm_buffer_pointer %= runtime->buffer_size;

        dst  = (void *)runtime->dma_area +
                                frames_to_bytes(runtime, pcm_buffer_pointer);
        remaining_frames = runtime->buffer_size - pcm_buffer_pointer;

        for (i = 0; i < frames; ++i) {
                for (c = 0; c < channels; ++c) {
                        *dst = le32_to_cpu(buffer[c]) & 0xffffff00;
                        dst++;
                }
                buffer += s->data_block_quadlets;
                if (--remaining_frames == 0)
                        dst = (void *)runtime->dma_area;
        }
}

static void write_pcm_silence(struct amdtp_stream *s,
                              __le32 *buffer, unsigned int frames)
{
        struct amdtp_ff *p = s->protocol;
        unsigned int i, c, channels = p->pcm_channels;

        for (i = 0; i < frames; ++i) {
                for (c = 0; c < channels; ++c)
                        buffer[c] = cpu_to_le32(0x00000000);
                buffer += s->data_block_quadlets;
        }
}

int amdtp_ff_add_pcm_hw_constraints(struct amdtp_stream *s,
                                    struct snd_pcm_runtime *runtime)
{
        int err;

        err = snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
        if (err < 0)
                return err;

        return amdtp_stream_add_pcm_hw_constraints(s, runtime);
}

static void process_it_ctx_payloads(struct amdtp_stream *s, const struct pkt_desc *desc,
                                    unsigned int count, struct snd_pcm_substream *pcm)
{
        unsigned int pcm_frames = 0;
        int i;

        for (i = 0; i < count; ++i) {
                __le32 *buf = (__le32 *)desc->ctx_payload;
                unsigned int data_blocks = desc->data_blocks;

                if (pcm) {
                        write_pcm_s32(s, pcm, buf, data_blocks, pcm_frames);
                        pcm_frames += data_blocks;
                } else {
                        write_pcm_silence(s, buf, data_blocks);
                }

                desc = amdtp_stream_next_packet_desc(s, desc);
        }
}

static void process_ir_ctx_payloads(struct amdtp_stream *s, const struct pkt_desc *desc,
                                    unsigned int count, struct snd_pcm_substream *pcm)
{
        unsigned int pcm_frames = 0;
        int i;

        for (i = 0; i < count; ++i) {
                __le32 *buf = (__le32 *)desc->ctx_payload;
                unsigned int data_blocks = desc->data_blocks;

                if (pcm) {
                        read_pcm_s32(s, pcm, buf, data_blocks, pcm_frames);
                        pcm_frames += data_blocks;
                }

                desc = amdtp_stream_next_packet_desc(s, desc);
        }
}

int amdtp_ff_init(struct amdtp_stream *s, struct fw_unit *unit,
                  enum amdtp_stream_direction dir)
{
        amdtp_stream_process_ctx_payloads_t process_ctx_payloads;

        if (dir == AMDTP_IN_STREAM)
                process_ctx_payloads = process_ir_ctx_payloads;
        else
                process_ctx_payloads = process_it_ctx_payloads;

        return amdtp_stream_init(s, unit, dir, CIP_BLOCKING | CIP_UNAWARE_SYT | CIP_NO_HEADER, 0,
                                 process_ctx_payloads, sizeof(struct amdtp_ff));
}