ASoC: sh: rz-ssi: Add SSI DMAC support
authorBiju Das <biju.das.jz@bp.renesas.com>
Fri, 13 Aug 2021 09:11:56 +0000 (10:11 +0100)
committerMark Brown <broonie@kernel.org>
Fri, 13 Aug 2021 12:17:18 +0000 (13:17 +0100)
Add SSI DMAC support to RZ/G2L SoC.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20210813091156.10700-4-biju.das.jz@bp.renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>
sound/soc/sh/rz-ssi.c

index 615fa81..ea8d33e 100644 (file)
@@ -7,6 +7,7 @@
 //
 
 #include <linux/clk.h>
+#include <linux/dmaengine.h>
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
@@ -86,6 +87,7 @@ struct rz_ssi_stream {
        struct rz_ssi_priv *priv;
        struct snd_pcm_substream *substream;
        int fifo_sample_size;   /* sample capacity of SSI FIFO */
+       int dma_buffer_pos;     /* The address for the next DMA descriptor */
        int period_counter;     /* for keeping track of periods transferred */
        int sample_width;
        int buffer_pos;         /* current frame position in the buffer */
@@ -94,6 +96,8 @@ struct rz_ssi_stream {
        int uerr_num;
        int oerr_num;
 
+       struct dma_chan *dma_ch;
+
        int (*transfer)(struct rz_ssi_priv *ssi, struct rz_ssi_stream *strm);
 };
 
@@ -105,6 +109,7 @@ struct rz_ssi_priv {
        struct clk *sfr_clk;
        struct clk *clk;
 
+       phys_addr_t phys;
        int irq_int;
        int irq_tx;
        int irq_rx;
@@ -128,8 +133,11 @@ struct rz_ssi_priv {
 
        bool lrckp_fsync_fall;  /* LR clock polarity (SSICR.LRCKP) */
        bool bckp_rise; /* Bit clock polarity (SSICR.BCKP) */
+       bool dma_rt;
 };
 
+static void rz_ssi_dma_complete(void *data);
+
 static void rz_ssi_reg_writel(struct rz_ssi_priv *priv, uint reg, u32 data)
 {
        writel(data, (priv->base + reg));
@@ -175,6 +183,11 @@ rz_ssi_stream_get(struct rz_ssi_priv *ssi, struct snd_pcm_substream *substream)
        return stream;
 }
 
+static inline bool rz_ssi_is_dma_enabled(struct rz_ssi_priv *ssi)
+{
+       return (ssi->playback.dma_ch || ssi->capture.dma_ch);
+}
+
 static int rz_ssi_stream_is_valid(struct rz_ssi_priv *ssi,
                                  struct rz_ssi_stream *strm)
 {
@@ -196,6 +209,7 @@ static int rz_ssi_stream_init(struct rz_ssi_priv *ssi,
 
        strm->substream = substream;
        strm->sample_width = samples_to_bytes(runtime, 1);
+       strm->dma_buffer_pos = 0;
        strm->period_counter = 0;
        strm->buffer_pos = 0;
 
@@ -297,9 +311,12 @@ static int rz_ssi_start(struct rz_ssi_priv *ssi, struct rz_ssi_stream *strm)
        ssifcr = rz_ssi_reg_readl(ssi, SSIFCR) & ~0xF;
 
        /* FIFO interrupt thresholds */
-       rz_ssi_reg_writel(ssi, SSISCR,
-                         SSISCR_TDES(strm->fifo_sample_size / 2 - 1) |
-                         SSISCR_RDFS(0));
+       if (rz_ssi_is_dma_enabled(ssi))
+               rz_ssi_reg_writel(ssi, SSISCR, 0);
+       else
+               rz_ssi_reg_writel(ssi, SSISCR,
+                                 SSISCR_TDES(strm->fifo_sample_size / 2 - 1) |
+                                 SSISCR_RDFS(0));
 
        /* enable IRQ */
        if (is_play) {
@@ -334,6 +351,10 @@ static int rz_ssi_stop(struct rz_ssi_priv *ssi, struct rz_ssi_stream *strm)
        /* Disable TX/RX */
        rz_ssi_reg_mask_setl(ssi, SSICR, SSICR_TEN | SSICR_REN, 0);
 
+       /* Cancel all remaining DMA transactions */
+       if (rz_ssi_is_dma_enabled(ssi))
+               dmaengine_terminate_async(strm->dma_ch);
+
        /* Disable irqs */
        rz_ssi_reg_mask_setl(ssi, SSICR, SSICR_TUIEN | SSICR_TOIEN |
                             SSICR_RUIEN | SSICR_ROIEN, 0);
@@ -549,12 +570,143 @@ static irqreturn_t rz_ssi_interrupt(int irq, void *data)
        return IRQ_HANDLED;
 }
 
+static int rz_ssi_dma_slave_config(struct rz_ssi_priv *ssi,
+                                  struct dma_chan *dma_ch, bool is_play)
+{
+       struct dma_slave_config cfg;
+
+       memset(&cfg, 0, sizeof(cfg));
+
+       cfg.direction = is_play ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM;
+       cfg.dst_addr = ssi->phys + SSIFTDR;
+       cfg.src_addr = ssi->phys + SSIFRDR;
+       cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
+       cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
+
+       return dmaengine_slave_config(dma_ch, &cfg);
+}
+
+static int rz_ssi_dma_transfer(struct rz_ssi_priv *ssi,
+                              struct rz_ssi_stream *strm)
+{
+       struct snd_pcm_substream *substream = strm->substream;
+       struct dma_async_tx_descriptor *desc;
+       struct snd_pcm_runtime *runtime;
+       enum dma_transfer_direction dir;
+       u32 dma_paddr, dma_size;
+       int amount;
+
+       if (!rz_ssi_stream_is_valid(ssi, strm))
+               return -EINVAL;
+
+       runtime = substream->runtime;
+       if (runtime->status->state == SNDRV_PCM_STATE_DRAINING)
+               /*
+                * Stream is ending, so do not queue up any more DMA
+                * transfers otherwise we play partial sound clips
+                * because we can't shut off the DMA quick enough.
+                */
+               return 0;
+
+       dir = rz_ssi_stream_is_play(ssi, substream) ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM;
+
+       /* Always transfer 1 period */
+       amount = runtime->period_size;
+
+       /* DMA physical address and size */
+       dma_paddr = runtime->dma_addr + frames_to_bytes(runtime,
+                                                       strm->dma_buffer_pos);
+       dma_size = frames_to_bytes(runtime, amount);
+       desc = dmaengine_prep_slave_single(strm->dma_ch, dma_paddr, dma_size,
+                                          dir,
+                                          DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+       if (!desc) {
+               dev_err(ssi->dev, "dmaengine_prep_slave_single() fail\n");
+               return -ENOMEM;
+       }
+
+       desc->callback = rz_ssi_dma_complete;
+       desc->callback_param = strm;
+
+       if (dmaengine_submit(desc) < 0) {
+               dev_err(ssi->dev, "dmaengine_submit() fail\n");
+               return -EIO;
+       }
+
+       /* Update DMA pointer */
+       strm->dma_buffer_pos += amount;
+       if (strm->dma_buffer_pos >= runtime->buffer_size)
+               strm->dma_buffer_pos = 0;
+
+       /* Start DMA */
+       dma_async_issue_pending(strm->dma_ch);
+
+       return 0;
+}
+
+static void rz_ssi_dma_complete(void *data)
+{
+       struct rz_ssi_stream *strm = (struct rz_ssi_stream *)data;
+
+       if (!strm->running || !strm->substream || !strm->substream->runtime)
+               return;
+
+       /* Note that next DMA transaction has probably already started */
+       rz_ssi_pointer_update(strm, strm->substream->runtime->period_size);
+
+       /* Queue up another DMA transaction */
+       rz_ssi_dma_transfer(strm->priv, strm);
+}
+
+static void rz_ssi_release_dma_channels(struct rz_ssi_priv *ssi)
+{
+       if (ssi->playback.dma_ch) {
+               dma_release_channel(ssi->playback.dma_ch);
+               ssi->playback.dma_ch = NULL;
+               if (ssi->dma_rt)
+                       ssi->dma_rt = false;
+       }
+
+       if (ssi->capture.dma_ch) {
+               dma_release_channel(ssi->capture.dma_ch);
+               ssi->capture.dma_ch = NULL;
+       }
+}
+
+static int rz_ssi_dma_request(struct rz_ssi_priv *ssi, struct device *dev)
+{
+       ssi->playback.dma_ch = dma_request_chan(dev, "tx");
+       ssi->capture.dma_ch = dma_request_chan(dev, "rx");
+       if (!ssi->playback.dma_ch && !ssi->capture.dma_ch) {
+               ssi->playback.dma_ch = dma_request_chan(dev, "rt");
+               if (!ssi->playback.dma_ch)
+                       goto no_dma;
+
+               ssi->dma_rt = true;
+       }
+
+       if (ssi->playback.dma_ch &&
+           (rz_ssi_dma_slave_config(ssi, ssi->playback.dma_ch, true) < 0))
+               goto no_dma;
+
+       if (ssi->capture.dma_ch &&
+           (rz_ssi_dma_slave_config(ssi, ssi->capture.dma_ch, false) < 0))
+               goto no_dma;
+
+       return 0;
+
+no_dma:
+       rz_ssi_release_dma_channels(ssi);
+
+       return -ENODEV;
+}
+
 static int rz_ssi_dai_trigger(struct snd_pcm_substream *substream, int cmd,
                              struct snd_soc_dai *dai)
 {
        struct rz_ssi_priv *ssi = snd_soc_dai_get_drvdata(dai);
        struct rz_ssi_stream *strm = rz_ssi_stream_get(ssi, substream);
-       int ret = 0;
+       int ret = 0, i, num_transfer = 1;
 
        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
@@ -567,9 +719,29 @@ static int rz_ssi_dai_trigger(struct snd_pcm_substream *substream, int cmd,
                if (ret)
                        goto done;
 
-               ret = strm->transfer(ssi, strm);
-               if (ret)
-                       goto done;
+               if (ssi->dma_rt) {
+                       bool is_playback;
+
+                       is_playback = rz_ssi_stream_is_play(ssi, substream);
+                       ret = rz_ssi_dma_slave_config(ssi, ssi->playback.dma_ch,
+                                                     is_playback);
+                       /* Fallback to pio */
+                       if (ret < 0) {
+                               ssi->playback.transfer = rz_ssi_pio_send;
+                               ssi->capture.transfer = rz_ssi_pio_recv;
+                               rz_ssi_release_dma_channels(ssi);
+                       }
+               }
+
+               /* For DMA, queue up multiple DMA descriptors */
+               if (rz_ssi_is_dma_enabled(ssi))
+                       num_transfer = 4;
+
+               for (i = 0; i < num_transfer; i++) {
+                       ret = strm->transfer(ssi, strm);
+                       if (ret)
+                               goto done;
+               }
 
                ret = rz_ssi_start(ssi, strm);
                break;
@@ -737,6 +909,7 @@ static int rz_ssi_probe(struct platform_device *pdev)
 {
        struct rz_ssi_priv *ssi;
        struct clk *audio_clk;
+       struct resource *res;
        int ret;
 
        ssi = devm_kzalloc(&pdev->dev, sizeof(*ssi), GFP_KERNEL);
@@ -745,10 +918,11 @@ static int rz_ssi_probe(struct platform_device *pdev)
 
        ssi->pdev = pdev;
        ssi->dev = &pdev->dev;
-       ssi->base = devm_platform_ioremap_resource(pdev, 0);
+       ssi->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
        if (IS_ERR(ssi->base))
                return PTR_ERR(ssi->base);
 
+       ssi->phys = res->start;
        ssi->clk = devm_clk_get(&pdev->dev, "ssi");
        if (IS_ERR(ssi->clk))
                return PTR_ERR(ssi->clk);
@@ -775,8 +949,18 @@ static int rz_ssi_probe(struct platform_device *pdev)
 
        ssi->audio_mck = ssi->audio_clk_1 ? ssi->audio_clk_1 : ssi->audio_clk_2;
 
-       ssi->playback.transfer = rz_ssi_pio_send;
-       ssi->capture.transfer = rz_ssi_pio_recv;
+       /* Detect DMA support */
+       ret = rz_ssi_dma_request(ssi, &pdev->dev);
+       if (ret < 0) {
+               dev_warn(&pdev->dev, "DMA not available, using PIO\n");
+               ssi->playback.transfer = rz_ssi_pio_send;
+               ssi->capture.transfer = rz_ssi_pio_recv;
+       } else {
+               dev_info(&pdev->dev, "DMA enabled");
+               ssi->playback.transfer = rz_ssi_dma_transfer;
+               ssi->capture.transfer = rz_ssi_dma_transfer;
+       }
+
        ssi->playback.priv = ssi;
        ssi->capture.priv = ssi;
 
@@ -792,28 +976,32 @@ static int rz_ssi_probe(struct platform_device *pdev)
                return dev_err_probe(&pdev->dev, ret,
                                     "irq request error (int_req)\n");
 
-       /* Tx and Rx interrupts (pio only) */
-       ssi->irq_tx = platform_get_irq_byname(pdev, "dma_tx");
-       if (ssi->irq_tx < 0)
-               return dev_err_probe(&pdev->dev, -ENODEV,
-                                    "Unable to get SSI dma_tx IRQ\n");
-
-       ret = devm_request_irq(&pdev->dev, ssi->irq_tx, &rz_ssi_interrupt, 0,
-                              dev_name(&pdev->dev), ssi);
-       if (ret < 0)
-               return dev_err_probe(&pdev->dev, ret,
-                                    "irq request error (dma_tx)\n");
-
-       ssi->irq_rx = platform_get_irq_byname(pdev, "dma_rx");
-       if (ssi->irq_rx < 0)
-               return dev_err_probe(&pdev->dev, -ENODEV,
-                                    "Unable to get SSI dma_rx IRQ\n");
-
-       ret = devm_request_irq(&pdev->dev, ssi->irq_rx, &rz_ssi_interrupt, 0,
-                              dev_name(&pdev->dev), ssi);
-       if (ret < 0)
-               return dev_err_probe(&pdev->dev, ret,
-                                    "irq request error (dma_rx)\n");
+       if (!rz_ssi_is_dma_enabled(ssi)) {
+               /* Tx and Rx interrupts (pio only) */
+               ssi->irq_tx = platform_get_irq_byname(pdev, "dma_tx");
+               if (ssi->irq_tx < 0)
+                       return dev_err_probe(&pdev->dev, -ENODEV,
+                                            "Unable to get SSI dma_tx IRQ\n");
+
+               ret = devm_request_irq(&pdev->dev, ssi->irq_tx,
+                                      &rz_ssi_interrupt, 0,
+                                      dev_name(&pdev->dev), ssi);
+               if (ret < 0)
+                       return dev_err_probe(&pdev->dev, ret,
+                                            "irq request error (dma_tx)\n");
+
+               ssi->irq_rx = platform_get_irq_byname(pdev, "dma_rx");
+               if (ssi->irq_rx < 0)
+                       return dev_err_probe(&pdev->dev, -ENODEV,
+                                            "Unable to get SSI dma_rx IRQ\n");
+
+               ret = devm_request_irq(&pdev->dev, ssi->irq_rx,
+                                      &rz_ssi_interrupt, 0,
+                                      dev_name(&pdev->dev), ssi);
+               if (ret < 0)
+                       return dev_err_probe(&pdev->dev, ret,
+                                            "irq request error (dma_rx)\n");
+       }
 
        ssi->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
        if (IS_ERR(ssi->rstc))
@@ -829,6 +1017,8 @@ static int rz_ssi_probe(struct platform_device *pdev)
                                              rz_ssi_soc_dai,
                                              ARRAY_SIZE(rz_ssi_soc_dai));
        if (ret < 0) {
+               rz_ssi_release_dma_channels(ssi);
+
                pm_runtime_put(ssi->dev);
                pm_runtime_disable(ssi->dev);
                reset_control_assert(ssi->rstc);
@@ -842,6 +1032,8 @@ static int rz_ssi_remove(struct platform_device *pdev)
 {
        struct rz_ssi_priv *ssi = dev_get_drvdata(&pdev->dev);
 
+       rz_ssi_release_dma_channels(ssi);
+
        pm_runtime_put(ssi->dev);
        pm_runtime_disable(ssi->dev);
        reset_control_assert(ssi->rstc);