From 702648721db590b3425c31ade294000e18808345 Mon Sep 17 00:00:00 2001 From: Paweł Anikiel Date: Mon, 8 May 2023 13:30:31 +0200 Subject: ASoC: Add Google Chameleon v3 i2s driver MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add driver for the i2s IP present on Google Chameleon v3 Signed-off-by: Paweł Anikiel +#include +#include + +#include + +/* + * The I2S interface consists of two ring buffers - one for RX and one for + * TX. A ring buffer has a producer index and a consumer index. Depending + * on which way the data is flowing, either the software or the hardware + * writes data and updates the producer index, and the other end reads data + * and updates the consumer index. + * + * The pointer managed by software is updated using the .ack callback + * (see chv3_dma_ack). This seems to be the only way to reliably obtain + * the appl_ptr from within the driver and pass it to hardware. + * + * Because of the two pointer design, the ring buffer can never be full. With + * capture this isn't a problem, because the hardware being the producer + * will wait for the consumer index to move out of the way. With playback, + * however, this is problematic, because ALSA wants to fill up the buffer + * completely when waiting for hardware. In the .ack callback, the driver + * would have to wait for the consumer index to move out of the way by + * busy-waiting, which would keep stalling the kernel for quite a long time. + * + * The workaround to this problem is to "lie" to ALSA that the hw_pointer + * is one frame behind what it actually is (see chv3_dma_pointer). This + * way, ALSA will not try to fill up the entire buffer, and all callbacks + * are wait-free. + */ + +#define I2S_TX_ENABLE 0x00 +#define I2S_TX_BASE_ADDR 0x04 +#define I2S_TX_BUFFER_SIZE 0x08 +#define I2S_TX_PRODUCER_IDX 0x0c +#define I2S_TX_CONSUMER_IDX 0x10 +#define I2S_RX_ENABLE 0x14 +#define I2S_RX_BASE_ADDR 0x18 +#define I2S_RX_BUFFER_SIZE 0x1c +#define I2S_RX_PRODUCER_IDX 0x20 +#define I2S_RX_CONSUMER_IDX 0x24 + +#define I2S_SOFT_RESET 0x2c +#define I2S_SOFT_RESET_RX_BIT 0x1 +#define I2S_SOFT_RESET_TX_BIT 0x2 + +#define I2S_RX_IRQ 0x4c +#define I2S_RX_IRQ_CONST 0x50 +#define I2S_TX_IRQ 0x54 +#define I2S_TX_IRQ_CONST 0x58 + +#define I2S_IRQ_MASK 0x8 +#define I2S_IRQ_CLR 0xc +#define I2S_IRQ_RX_BIT 0x1 +#define I2S_IRQ_TX_BIT 0x2 + +#define I2S_MAX_BUFFER_SIZE 0x200000 + +struct chv3_i2s_dev { + struct device *dev; + void __iomem *iobase; + void __iomem *iobase_irq; + struct snd_pcm_substream *rx_substream; + struct snd_pcm_substream *tx_substream; + int tx_bytes_to_fetch; +}; + +static struct snd_soc_dai_driver chv3_i2s_dai = { + .name = "chv3-i2s", + .capture = { + .channels_min = 1, + .channels_max = 128, + .rates = SNDRV_PCM_RATE_CONTINUOUS, + .rate_min = 8000, + .rate_max = 96000, + .formats = SNDRV_PCM_FMTBIT_S32_LE, + }, + .playback = { + .channels_min = 1, + .channels_max = 128, + .rates = SNDRV_PCM_RATE_CONTINUOUS, + .rate_min = 8000, + .rate_max = 96000, + .formats = SNDRV_PCM_FMTBIT_S32_LE, + }, +}; + +static const struct snd_pcm_hardware chv3_dma_hw = { + .info = SNDRV_PCM_INFO_INTERLEAVED | + SNDRV_PCM_INFO_MMAP | + SNDRV_PCM_INFO_MMAP_VALID | + SNDRV_PCM_INFO_BLOCK_TRANSFER, + .buffer_bytes_max = I2S_MAX_BUFFER_SIZE, + .period_bytes_min = 64, + .period_bytes_max = 8192, + .periods_min = 4, + .periods_max = 256, +}; + +static inline void chv3_i2s_wr(struct chv3_i2s_dev *i2s, int offset, u32 val) +{ + writel(val, i2s->iobase + offset); +} + +static inline u32 chv3_i2s_rd(struct chv3_i2s_dev *i2s, int offset) +{ + return readl(i2s->iobase + offset); +} + +static irqreturn_t chv3_i2s_isr(int irq, void *data) +{ + struct chv3_i2s_dev *i2s = data; + u32 reg; + + reg = readl(i2s->iobase_irq + I2S_IRQ_CLR); + if (!reg) + return IRQ_NONE; + + if (reg & I2S_IRQ_RX_BIT) + snd_pcm_period_elapsed(i2s->rx_substream); + + if (reg & I2S_IRQ_TX_BIT) + snd_pcm_period_elapsed(i2s->tx_substream); + + writel(reg, i2s->iobase_irq + I2S_IRQ_CLR); + + return IRQ_HANDLED; +} + +static int chv3_dma_open(struct snd_soc_component *component, + struct snd_pcm_substream *substream) +{ + struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream); + struct chv3_i2s_dev *i2s = snd_soc_dai_get_drvdata(asoc_rtd_to_cpu(rtd, 0)); + int res; + + snd_soc_set_runtime_hwparams(substream, &chv3_dma_hw); + + res = snd_pcm_hw_constraint_pow2(substream->runtime, 0, + SNDRV_PCM_HW_PARAM_BUFFER_BYTES); + if (res) + return res; + + if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) + i2s->rx_substream = substream; + else + i2s->tx_substream = substream; + + return 0; +} +static int chv3_dma_close(struct snd_soc_component *component, + struct snd_pcm_substream *substream) +{ + struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream); + struct chv3_i2s_dev *i2s = snd_soc_dai_get_drvdata(asoc_rtd_to_cpu(rtd, 0)); + + if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE) + chv3_i2s_wr(i2s, I2S_RX_ENABLE, 0); + else + chv3_i2s_wr(i2s, I2S_TX_ENABLE, 0); + + return 0; +} + +static int chv3_dma_pcm_construct(struct snd_soc_component *component, + struct snd_soc_pcm_runtime *rtd) +{ + struct chv3_i2s_dev *i2s = snd_soc_dai_get_drvdata(asoc_rtd_to_cpu(rtd, 0)); + struct snd_pcm_substream *substream; + int res; + + substream = rtd->pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream; + if (substream) { + res = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, i2s->dev, + I2S_MAX_BUFFER_SIZE, &substream->dma_buffer); + if (res) + return res; + } + + substream = rtd->pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream; + if (substream) { + res = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, i2s->dev, + I2S_MAX_BUFFER_SIZE, &substream->dma_buffer); + if (res) + return res; + } + + return 0; +} + +static int chv3_dma_hw_params(struct snd_soc_component *component, + struct snd_pcm_substream *substream, + struct snd_pcm_hw_params *params) +{ + snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer); + return 0; +} + +static int chv3_dma_prepare(struct snd_soc_component *component, + struct snd_pcm_substream *substream) +{ + struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream); + struct chv3_i2s_dev *i2s = snd_soc_dai_get_drvdata(asoc_rtd_to_cpu(rtd, 0)); + unsigned int buffer_bytes, period_bytes, period_size; + + buffer_bytes = snd_pcm_lib_buffer_bytes(substream); + period_bytes = snd_pcm_lib_period_bytes(substream); + period_size = substream->runtime->period_size; + + if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE) { + chv3_i2s_wr(i2s, I2S_SOFT_RESET, I2S_SOFT_RESET_RX_BIT); + chv3_i2s_wr(i2s, I2S_RX_BASE_ADDR, substream->dma_buffer.addr); + chv3_i2s_wr(i2s, I2S_RX_BUFFER_SIZE, buffer_bytes); + chv3_i2s_wr(i2s, I2S_RX_IRQ, (period_size << 8) | 1); + chv3_i2s_wr(i2s, I2S_RX_ENABLE, 1); + } else { + chv3_i2s_wr(i2s, I2S_SOFT_RESET, I2S_SOFT_RESET_TX_BIT); + chv3_i2s_wr(i2s, I2S_TX_BASE_ADDR, substream->dma_buffer.addr); + chv3_i2s_wr(i2s, I2S_TX_BUFFER_SIZE, buffer_bytes); + chv3_i2s_wr(i2s, I2S_TX_IRQ, ((period_bytes / i2s->tx_bytes_to_fetch) << 8) | 1); + chv3_i2s_wr(i2s, I2S_TX_ENABLE, 1); + } + writel(I2S_IRQ_RX_BIT | I2S_IRQ_TX_BIT, i2s->iobase_irq + I2S_IRQ_MASK); + + return 0; +} + +static snd_pcm_uframes_t chv3_dma_pointer(struct snd_soc_component *component, + struct snd_pcm_substream *substream) +{ + struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream); + struct chv3_i2s_dev *i2s = snd_soc_dai_get_drvdata(asoc_rtd_to_cpu(rtd, 0)); + u32 frame_bytes, buffer_bytes; + u32 idx_bytes; + + frame_bytes = substream->runtime->frame_bits * 8; + buffer_bytes = snd_pcm_lib_buffer_bytes(substream); + + if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE) { + idx_bytes = chv3_i2s_rd(i2s, I2S_RX_PRODUCER_IDX); + } else { + idx_bytes = chv3_i2s_rd(i2s, I2S_TX_CONSUMER_IDX); + /* lag the pointer by one frame */ + idx_bytes = (idx_bytes - frame_bytes) & (buffer_bytes - 1); + } + + return bytes_to_frames(substream->runtime, idx_bytes); +} + +static int chv3_dma_ack(struct snd_soc_component *component, + struct snd_pcm_substream *substream) +{ + struct snd_pcm_runtime *runtime = substream->runtime; + struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream); + struct chv3_i2s_dev *i2s = snd_soc_dai_get_drvdata(asoc_rtd_to_cpu(rtd, 0)); + unsigned int bytes, idx; + + bytes = frames_to_bytes(runtime, runtime->control->appl_ptr); + idx = bytes & (snd_pcm_lib_buffer_bytes(substream) - 1); + + if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE) + chv3_i2s_wr(i2s, I2S_RX_CONSUMER_IDX, idx); + else + chv3_i2s_wr(i2s, I2S_TX_PRODUCER_IDX, idx); + + return 0; +} + +static const struct snd_soc_component_driver chv3_i2s_comp = { + .name = "chv3-i2s-comp", + .open = chv3_dma_open, + .close = chv3_dma_close, + .pcm_construct = chv3_dma_pcm_construct, + .hw_params = chv3_dma_hw_params, + .prepare = chv3_dma_prepare, + .pointer = chv3_dma_pointer, + .ack = chv3_dma_ack, +}; + +static int chv3_i2s_probe(struct platform_device *pdev) +{ + struct chv3_i2s_dev *i2s; + int res; + int irq; + + i2s = devm_kzalloc(&pdev->dev, sizeof(*i2s), GFP_KERNEL); + if (!i2s) + return -ENOMEM; + + i2s->iobase = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(i2s->iobase)) + return PTR_ERR(i2s->iobase); + + i2s->iobase_irq = devm_platform_ioremap_resource(pdev, 1); + if (IS_ERR(i2s->iobase_irq)) + return PTR_ERR(i2s->iobase_irq); + + i2s->tx_bytes_to_fetch = (chv3_i2s_rd(i2s, I2S_TX_IRQ_CONST) >> 8) & 0xffff; + + i2s->dev = &pdev->dev; + dev_set_drvdata(&pdev->dev, i2s); + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return -ENXIO; + res = devm_request_irq(i2s->dev, irq, chv3_i2s_isr, 0, "chv3-i2s", i2s); + if (res) + return res; + + res = devm_snd_soc_register_component(&pdev->dev, &chv3_i2s_comp, + &chv3_i2s_dai, 1); + if (res) { + dev_err(&pdev->dev, "couldn't register component: %d\n", res); + return res; + } + + return 0; +} + +static const struct of_device_id chv3_i2s_of_match[] = { + { .compatible = "google,chv3-i2s" }, + {}, +}; + +static struct platform_driver chv3_i2s_driver = { + .probe = chv3_i2s_probe, + .driver = { + .name = "chv3-i2s", + .of_match_table = chv3_i2s_of_match, + }, +}; + +module_platform_driver(chv3_i2s_driver); + +MODULE_AUTHOR("Pawel Anikiel "); +MODULE_DESCRIPTION("Chameleon v3 I2S interface"); +MODULE_LICENSE("GPL"); -- cgit