// SPDX-License-Identifier: GPL-2.0
//
// SH7760 ("camelot") DMABRG audio DMA unit support
//
// Copyright (C) 2007 Manuel Lauss <[email protected]>
//
// The SH7760 DMABRG provides 4 dma channels (2x rec, 2x play), which
// trigger an interrupt when one half of the programmed transfer size
// has been xmitted.
//
// FIXME: little-endian only for now
#include <linux/module.h>
#include <linux/gfp.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>
#include <asm/dmabrg.h>
/* registers and bits */
#define BRGATXSAR 0x00
#define BRGARXDAR 0x04
#define BRGATXTCR 0x08
#define BRGARXTCR 0x0C
#define BRGACR 0x10
#define BRGATXTCNT 0x14
#define BRGARXTCNT 0x18
#define ACR_RAR (1 << 18)
#define ACR_RDS (1 << 17)
#define ACR_RDE (1 << 16)
#define ACR_TAR (1 << 2)
#define ACR_TDS (1 << 1)
#define ACR_TDE (1 << 0)
/* receiver/transmitter data alignment */
#define ACR_RAM_NONE (0 << 24)
#define ACR_RAM_4BYTE (1 << 24)
#define ACR_RAM_2WORD (2 << 24)
#define ACR_TAM_NONE (0 << 8)
#define ACR_TAM_4BYTE (1 << 8)
#define ACR_TAM_2WORD (2 << 8)
struct camelot_pcm {
unsigned long mmio; /* DMABRG audio channel control reg MMIO */
unsigned int txid; /* ID of first DMABRG IRQ for this unit */
struct snd_pcm_substream *tx_ss;
unsigned long tx_period_size;
unsigned int tx_period;
struct snd_pcm_substream *rx_ss;
unsigned long rx_period_size;
unsigned int rx_period;
} cam_pcm_data[2] = {
{
.mmio = 0xFE3C0040,
.txid = DMABRGIRQ_A0TXF,
},
{
.mmio = 0xFE3C0060,
.txid = DMABRGIRQ_A1TXF,
},
};
#define BRGREG(x) (*(unsigned long *)(cam->mmio + (x)))
/*
* set a minimum of 16kb per period, to avoid interrupt-"storm" and
* resulting skipping. In general, the bigger the minimum size, the
* better for overall system performance. (The SH7760 is a puny CPU
* with a slow SDRAM interface and poor internal bus bandwidth,
* *especially* when the LCDC is active). The minimum for the DMAC
* is 8 bytes; 16kbytes are enough to get skip-free playback of a
* 44kHz/16bit/stereo MP3 on a lightly loaded system, and maintain
* reasonable responsiveness in MPlayer.
*/
#define DMABRG_PERIOD_MIN 16 * 1024
#define DMABRG_PERIOD_MAX 0x03fffffc
#define DMABRG_PREALLOC_BUFFER 32 * 1024
#define DMABRG_PREALLOC_BUFFER_MAX 32 * 1024
static const struct snd_pcm_hardware camelot_pcm_hardware = {
.info = (SNDRV_PCM_INFO_MMAP |
SNDRV_PCM_INFO_INTERLEAVED |
SNDRV_PCM_INFO_BLOCK_TRANSFER |
SNDRV_PCM_INFO_MMAP_VALID |
SNDRV_PCM_INFO_BATCH),
.buffer_bytes_max = DMABRG_PERIOD_MAX,
.period_bytes_min = DMABRG_PERIOD_MIN,
.period_bytes_max = DMABRG_PERIOD_MAX / 2,
.periods_min = 2,
.periods_max = 2,
.fifo_size = 128,
};
static void camelot_txdma(void *data)
{
struct camelot_pcm *cam = data;
cam->tx_period ^= 1;
snd_pcm_period_elapsed(cam->tx_ss);
}
static void camelot_rxdma(void *data)
{
struct camelot_pcm *cam = data;
cam->rx_period ^= 1;
snd_pcm_period_elapsed(cam->rx_ss);
}
static int camelot_pcm_open(struct snd_soc_component *component,
struct snd_pcm_substream *substream)
{
struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
struct camelot_pcm *cam = &cam_pcm_data[snd_soc_rtd_to_cpu(rtd, 0)->id];
int recv = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0:1;
int ret, dmairq;
snd_soc_set_runtime_hwparams(substream, &camelot_pcm_hardware);
/* DMABRG buffer half/full events */
dmairq = (recv) ? cam->txid + 2 : cam->txid;
if (recv) {
cam->rx_ss = substream;
ret = dmabrg_request_irq(dmairq, camelot_rxdma, cam);
if (unlikely(ret)) {
pr_debug("audio unit %d irqs already taken!\n",
snd_soc_rtd_to_cpu(rtd, 0)->id);
return -EBUSY;
}
(void)dmabrg_request_irq(dmairq + 1,camelot_rxdma, cam);
} else {
cam->tx_ss = substream;
ret = dmabrg_request_irq(dmairq, camelot_txdma, cam);
if (unlikely(ret)) {
pr_debug("audio unit %d irqs already taken!\n",
snd_soc_rtd_to_cpu(rtd, 0)->id);
return -EBUSY;
}
(void)dmabrg_request_irq(dmairq + 1, camelot_txdma, cam);
}
return 0;
}
static int camelot_pcm_close(struct snd_soc_component *component,
struct snd_pcm_substream *substream)
{
struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
struct camelot_pcm *cam = &cam_pcm_data[snd_soc_rtd_to_cpu(rtd, 0)->id];
int recv = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0:1;
int dmairq;
dmairq = (recv) ? cam->txid + 2 : cam->txid;
if (recv)
cam->rx_ss = NULL;
else
cam->tx_ss = NULL;
dmabrg_free_irq(dmairq + 1);
dmabrg_free_irq(dmairq);
return 0;
}
static int camelot_hw_params(struct snd_soc_component *component,
struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *hw_params)
{
struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
struct camelot_pcm *cam = &cam_pcm_data[snd_soc_rtd_to_cpu(rtd, 0)->id];
int recv = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0:1;
if (recv) {
cam->rx_period_size = params_period_bytes(hw_params);
cam->rx_period = 0;
} else {
cam->tx_period_size = params_period_bytes(hw_params);
cam->tx_period = 0;
}
return 0;
}
static int camelot_prepare(struct snd_soc_component *component,
struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
struct camelot_pcm *cam = &cam_pcm_data[snd_soc_rtd_to_cpu(rtd, 0)->id];
pr_debug("PCM data: addr %pad len %zu\n", &runtime->dma_addr,
runtime->dma_bytes);
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
BRGREG(BRGATXSAR) = (unsigned long)runtime->dma_area;
BRGREG(BRGATXTCR) = runtime->dma_bytes;
} else {
BRGREG(BRGARXDAR) = (unsigned long)runtime->dma_area;
BRGREG(BRGARXTCR) = runtime->dma_bytes;
}
return 0;
}
static inline void dmabrg_play_dma_start(struct camelot_pcm *cam)
{
unsigned long acr = BRGREG(BRGACR) & ~(ACR_TDS | ACR_RDS);
/* start DMABRG engine: XFER start, auto-addr-reload */
BRGREG(BRGACR) = acr | ACR_TDE | ACR_TAR | ACR_TAM_2WORD;
}
static inline void dmabrg_play_dma_stop(struct camelot_pcm *cam)
{
unsigned long acr = BRGREG(BRGACR) & ~(ACR_TDS | ACR_RDS);
/* forcibly terminate data transmission */
BRGREG(BRGACR) = acr | ACR_TDS;
}
static inline void dmabrg_rec_dma_start(struct camelot_pcm *cam)
{
unsigned long acr = BRGREG(BRGACR) & ~(ACR_TDS | ACR_RDS);
/* start DMABRG engine: recv start, auto-reload */
BRGREG(BRGACR) = acr | ACR_RDE | ACR_RAR | ACR_RAM_2WORD;
}
static inline void dmabrg_rec_dma_stop(struct camelot_pcm *cam)
{
unsigned long acr = BRGREG(BRGACR) & ~(ACR_TDS | ACR_RDS);
/* forcibly terminate data receiver */
BRGREG(BRGACR) = acr | ACR_RDS;
}
static int camelot_trigger(struct snd_soc_component *component,
struct snd_pcm_substream *substream, int cmd)
{
struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
struct camelot_pcm *cam = &cam_pcm_data[snd_soc_rtd_to_cpu(rtd, 0)->id];
int recv = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0:1;
switch (cmd) {
case SNDRV_PCM_TRIGGER_START:
if (recv)
dmabrg_rec_dma_start(cam);
else
dmabrg_play_dma_start(cam);
break;
case SNDRV_PCM_TRIGGER_STOP:
if (recv)
dmabrg_rec_dma_stop(cam);
else
dmabrg_play_dma_stop(cam);
break;
default:
return -EINVAL;
}
return 0;
}
static snd_pcm_uframes_t camelot_pos(struct snd_soc_component *component,
struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
struct camelot_pcm *cam = &cam_pcm_data[snd_soc_rtd_to_cpu(rtd, 0)->id];
int recv = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0:1;
unsigned long pos;
/* cannot use the DMABRG pointer register: under load, by the
* time ALSA comes around to read the register, it is already
* far ahead (or worse, already done with the fragment) of the
* position at the time the IRQ was triggered, which results in
* fast-playback sound in my test application (ScummVM)
*/
if (recv)
pos = cam->rx_period ? cam->rx_period_size : 0;
else
pos = cam->tx_period ? cam->tx_period_size : 0;
return bytes_to_frames(runtime, pos);
}
static int camelot_pcm_new(struct snd_soc_component *component,
struct snd_soc_pcm_runtime *rtd)
{
struct snd_pcm *pcm = rtd->pcm;
/* dont use SNDRV_DMA_TYPE_DEV, since it will oops the SH kernel
* in MMAP mode (i.e. aplay -M)
*/
snd_pcm_set_managed_buffer_all(pcm,
SNDRV_DMA_TYPE_CONTINUOUS,
NULL,
DMABRG_PREALLOC_BUFFER, DMABRG_PREALLOC_BUFFER_MAX);
return 0;
}
static const struct snd_soc_component_driver sh7760_soc_component = {
.open = camelot_pcm_open,
.close = camelot_pcm_close,
.hw_params = camelot_hw_params,
.prepare = camelot_prepare,
.trigger = camelot_trigger,
.pointer = camelot_pos,
.pcm_construct = camelot_pcm_new,
};
static int sh7760_soc_platform_probe(struct platform_device *pdev)
{
return devm_snd_soc_register_component(&pdev->dev, &sh7760_soc_component,
NULL, 0);
}
static struct platform_driver sh7760_pcm_driver = {
.driver = {
.name = "sh7760-pcm-audio",
},
.probe = sh7760_soc_platform_probe,
};
module_platform_driver(sh7760_pcm_driver);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("SH7760 Audio DMA (DMABRG) driver");
MODULE_AUTHOR("Manuel Lauss <[email protected]>");
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