[PATCH 5.10.y-cip 03/31] ASoC: sh: Add RZ/G2L SSIF-2 driver


Lad Prabhakar
 

From: Biju Das <biju.das.jz@bp.renesas.com>

commit 03e786bd43410fa93e5d2459f7a43e90ff0ae801 upstream.

Add serial sound interface(SSIF-2) driver support for
RZ/G2L SoC.

Based on the work done by Chris Brandt for RZ/A SSI driver.

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/20210813091156.10700-2-biju.das.jz@bp.renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
sound/soc/sh/Kconfig | 6 +
sound/soc/sh/Makefile | 4 +
sound/soc/sh/rz-ssi.c | 871 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 881 insertions(+)
create mode 100644 sound/soc/sh/rz-ssi.c

diff --git a/sound/soc/sh/Kconfig b/sound/soc/sh/Kconfig
index ef8a29b9f641..f19bd15c0900 100644
--- a/sound/soc/sh/Kconfig
+++ b/sound/soc/sh/Kconfig
@@ -44,6 +44,12 @@ config SND_SOC_RCAR
help
This option enables R-Car SRU/SCU/SSIU/SSI sound support

+config SND_SOC_RZ
+ tristate "RZ/G2L series SSIF-2 support"
+ depends on ARCH_R9A07G044 || COMPILE_TEST
+ help
+ This option enables RZ/G2L SSIF-2 sound support.
+
##
## Boards
##
diff --git a/sound/soc/sh/Makefile b/sound/soc/sh/Makefile
index 51bd7c81671c..f6fd79948f6a 100644
--- a/sound/soc/sh/Makefile
+++ b/sound/soc/sh/Makefile
@@ -22,3 +22,7 @@ snd-soc-migor-objs := migor.o

obj-$(CONFIG_SND_SH7760_AC97) += snd-soc-sh7760-ac97.o
obj-$(CONFIG_SND_SIU_MIGOR) += snd-soc-migor.o
+
+# RZ/G2L
+snd-soc-rz-ssi-objs := rz-ssi.o
+obj-$(CONFIG_SND_SOC_RZ) += snd-soc-rz-ssi.o
diff --git a/sound/soc/sh/rz-ssi.c b/sound/soc/sh/rz-ssi.c
new file mode 100644
index 000000000000..615fa81f061e
--- /dev/null
+++ b/sound/soc/sh/rz-ssi.c
@@ -0,0 +1,871 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Renesas RZ/G2L ASoC Serial Sound Interface (SSIF-2) Driver
+//
+// Copyright (C) 2021 Renesas Electronics Corp.
+// Copyright (C) 2019 Chris Brandt.
+//
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/reset.h>
+#include <sound/soc.h>
+
+/* REGISTER OFFSET */
+#define SSICR 0x000
+#define SSISR 0x004
+#define SSIFCR 0x010
+#define SSIFSR 0x014
+#define SSIFTDR 0x018
+#define SSIFRDR 0x01c
+#define SSIOFR 0x020
+#define SSISCR 0x024
+
+/* SSI REGISTER BITS */
+#define SSICR_DWL(x) (((x) & 0x7) << 19)
+#define SSICR_SWL(x) (((x) & 0x7) << 16)
+#define SSICR_MST BIT(14)
+#define SSICR_CKDV(x) (((x) & 0xf) << 4)
+
+#define SSICR_CKS BIT(30)
+#define SSICR_TUIEN BIT(29)
+#define SSICR_TOIEN BIT(28)
+#define SSICR_RUIEN BIT(27)
+#define SSICR_ROIEN BIT(26)
+#define SSICR_MST BIT(14)
+#define SSICR_BCKP BIT(13)
+#define SSICR_LRCKP BIT(12)
+#define SSICR_CKDV(x) (((x) & 0xf) << 4)
+#define SSICR_TEN BIT(1)
+#define SSICR_REN BIT(0)
+
+#define SSISR_TUIRQ BIT(29)
+#define SSISR_TOIRQ BIT(28)
+#define SSISR_RUIRQ BIT(27)
+#define SSISR_ROIRQ BIT(26)
+#define SSISR_IIRQ BIT(25)
+
+#define SSIFCR_AUCKE BIT(31)
+#define SSIFCR_SSIRST BIT(16)
+#define SSIFCR_TIE BIT(3)
+#define SSIFCR_RIE BIT(2)
+#define SSIFCR_TFRST BIT(1)
+#define SSIFCR_RFRST BIT(0)
+
+#define SSIFSR_TDC_MASK 0x3f
+#define SSIFSR_TDC_SHIFT 24
+#define SSIFSR_RDC_MASK 0x3f
+#define SSIFSR_RDC_SHIFT 8
+
+#define SSIFSR_TDC(x) (((x) & 0x1f) << 24)
+#define SSIFSR_TDE BIT(16)
+#define SSIFSR_RDC(x) (((x) & 0x1f) << 8)
+#define SSIFSR_RDF BIT(0)
+
+#define SSIOFR_LRCONT BIT(8)
+
+#define SSISCR_TDES(x) (((x) & 0x1f) << 8)
+#define SSISCR_RDFS(x) (((x) & 0x1f) << 0)
+
+/* Pre allocated buffers sizes */
+#define PREALLOC_BUFFER (SZ_32K)
+#define PREALLOC_BUFFER_MAX (SZ_32K)
+
+#define SSI_RATES SNDRV_PCM_RATE_8000_48000 /* 8k-44.1kHz */
+#define SSI_FMTS SNDRV_PCM_FMTBIT_S16_LE
+#define SSI_CHAN_MIN 2
+#define SSI_CHAN_MAX 2
+#define SSI_FIFO_DEPTH 32
+
+struct rz_ssi_priv;
+
+struct rz_ssi_stream {
+ struct rz_ssi_priv *priv;
+ struct snd_pcm_substream *substream;
+ int fifo_sample_size; /* sample capacity of SSI FIFO */
+ int period_counter; /* for keeping track of periods transferred */
+ int sample_width;
+ int buffer_pos; /* current frame position in the buffer */
+ int running; /* 0=stopped, 1=running */
+
+ int uerr_num;
+ int oerr_num;
+
+ int (*transfer)(struct rz_ssi_priv *ssi, struct rz_ssi_stream *strm);
+};
+
+struct rz_ssi_priv {
+ void __iomem *base;
+ struct platform_device *pdev;
+ struct reset_control *rstc;
+ struct device *dev;
+ struct clk *sfr_clk;
+ struct clk *clk;
+
+ int irq_int;
+ int irq_tx;
+ int irq_rx;
+
+ spinlock_t lock;
+
+ /*
+ * The SSI supports full-duplex transmission and reception.
+ * However, if an error occurs, channel reset (both transmission
+ * and reception reset) is required.
+ * So it is better to use as half-duplex (playing and recording
+ * should be done on separate channels).
+ */
+ struct rz_ssi_stream playback;
+ struct rz_ssi_stream capture;
+
+ /* clock */
+ unsigned long audio_mck;
+ unsigned long audio_clk_1;
+ unsigned long audio_clk_2;
+
+ bool lrckp_fsync_fall; /* LR clock polarity (SSICR.LRCKP) */
+ bool bckp_rise; /* Bit clock polarity (SSICR.BCKP) */
+};
+
+static void rz_ssi_reg_writel(struct rz_ssi_priv *priv, uint reg, u32 data)
+{
+ writel(data, (priv->base + reg));
+}
+
+static u32 rz_ssi_reg_readl(struct rz_ssi_priv *priv, uint reg)
+{
+ return readl(priv->base + reg);
+}
+
+static void rz_ssi_reg_mask_setl(struct rz_ssi_priv __iomem *priv, uint reg,
+ u32 bclr, u32 bset)
+{
+ u32 val;
+
+ val = readl(priv->base + reg);
+ val = (val & ~bclr) | bset;
+ writel(val, (priv->base + reg));
+}
+
+static inline struct snd_soc_dai *
+rz_ssi_get_dai(struct snd_pcm_substream *substream)
+{
+ struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+
+ return asoc_rtd_to_cpu(rtd, 0);
+}
+
+static inline bool rz_ssi_stream_is_play(struct rz_ssi_priv *ssi,
+ struct snd_pcm_substream *substream)
+{
+ return substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
+}
+
+static inline struct rz_ssi_stream *
+rz_ssi_stream_get(struct rz_ssi_priv *ssi, struct snd_pcm_substream *substream)
+{
+ struct rz_ssi_stream *stream = &ssi->playback;
+
+ if (substream->stream != SNDRV_PCM_STREAM_PLAYBACK)
+ stream = &ssi->capture;
+
+ return stream;
+}
+
+static int rz_ssi_stream_is_valid(struct rz_ssi_priv *ssi,
+ struct rz_ssi_stream *strm)
+{
+ unsigned long flags;
+ int ret;
+
+ spin_lock_irqsave(&ssi->lock, flags);
+ ret = !!(strm->substream && strm->substream->runtime);
+ spin_unlock_irqrestore(&ssi->lock, flags);
+
+ return ret;
+}
+
+static int rz_ssi_stream_init(struct rz_ssi_priv *ssi,
+ struct rz_ssi_stream *strm,
+ struct snd_pcm_substream *substream)
+{
+ struct snd_pcm_runtime *runtime = substream->runtime;
+
+ strm->substream = substream;
+ strm->sample_width = samples_to_bytes(runtime, 1);
+ strm->period_counter = 0;
+ strm->buffer_pos = 0;
+
+ strm->oerr_num = 0;
+ strm->uerr_num = 0;
+ strm->running = 0;
+
+ /* fifo init */
+ strm->fifo_sample_size = SSI_FIFO_DEPTH;
+
+ return 0;
+}
+
+static void rz_ssi_stream_quit(struct rz_ssi_priv *ssi,
+ struct rz_ssi_stream *strm)
+{
+ struct snd_soc_dai *dai = rz_ssi_get_dai(strm->substream);
+ unsigned long flags;
+
+ spin_lock_irqsave(&ssi->lock, flags);
+ strm->substream = NULL;
+ spin_unlock_irqrestore(&ssi->lock, flags);
+
+ if (strm->oerr_num > 0)
+ dev_info(dai->dev, "overrun = %d\n", strm->oerr_num);
+
+ if (strm->uerr_num > 0)
+ dev_info(dai->dev, "underrun = %d\n", strm->uerr_num);
+}
+
+static int rz_ssi_clk_setup(struct rz_ssi_priv *ssi, unsigned int rate,
+ unsigned int channels)
+{
+ static s8 ckdv[16] = { 1, 2, 4, 8, 16, 32, 64, 128,
+ 6, 12, 24, 48, 96, -1, -1, -1 };
+ unsigned int channel_bits = 32; /* System Word Length */
+ unsigned long bclk_rate = rate * channels * channel_bits;
+ unsigned int div;
+ unsigned int i;
+ u32 ssicr = 0;
+ u32 clk_ckdv;
+
+ /* Clear AUCKE so we can set MST */
+ rz_ssi_reg_writel(ssi, SSIFCR, 0);
+
+ /* Continue to output LRCK pin even when idle */
+ rz_ssi_reg_writel(ssi, SSIOFR, SSIOFR_LRCONT);
+ if (ssi->audio_clk_1 && ssi->audio_clk_2) {
+ if (ssi->audio_clk_1 % bclk_rate)
+ ssi->audio_mck = ssi->audio_clk_2;
+ else
+ ssi->audio_mck = ssi->audio_clk_1;
+ }
+
+ /* Clock setting */
+ ssicr |= SSICR_MST;
+ if (ssi->audio_mck == ssi->audio_clk_1)
+ ssicr |= SSICR_CKS;
+ if (ssi->bckp_rise)
+ ssicr |= SSICR_BCKP;
+ if (ssi->lrckp_fsync_fall)
+ ssicr |= SSICR_LRCKP;
+
+ /* Determine the clock divider */
+ clk_ckdv = 0;
+ div = ssi->audio_mck / bclk_rate;
+ /* try to find an match */
+ for (i = 0; i < ARRAY_SIZE(ckdv); i++) {
+ if (ckdv[i] == div) {
+ clk_ckdv = i;
+ break;
+ }
+ }
+
+ if (i == ARRAY_SIZE(ckdv)) {
+ dev_err(ssi->dev, "Rate not divisible by audio clock source\n");
+ return -EINVAL;
+ }
+
+ /*
+ * DWL: Data Word Length = 16 bits
+ * SWL: System Word Length = 32 bits
+ */
+ ssicr |= SSICR_CKDV(clk_ckdv);
+ ssicr |= SSICR_DWL(1) | SSICR_SWL(3);
+ rz_ssi_reg_writel(ssi, SSICR, ssicr);
+ rz_ssi_reg_writel(ssi, SSIFCR,
+ (SSIFCR_AUCKE | SSIFCR_TFRST | SSIFCR_RFRST));
+
+ return 0;
+}
+
+static int rz_ssi_start(struct rz_ssi_priv *ssi, struct rz_ssi_stream *strm)
+{
+ bool is_play = rz_ssi_stream_is_play(ssi, strm->substream);
+ u32 ssicr, ssifcr;
+
+ ssicr = rz_ssi_reg_readl(ssi, SSICR);
+ 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));
+
+ /* enable IRQ */
+ if (is_play) {
+ ssicr |= SSICR_TUIEN | SSICR_TOIEN;
+ ssifcr |= SSIFCR_TIE | SSIFCR_RFRST;
+ } else {
+ ssicr |= SSICR_RUIEN | SSICR_ROIEN;
+ ssifcr |= SSIFCR_RIE | SSIFCR_TFRST;
+ }
+
+ rz_ssi_reg_writel(ssi, SSICR, ssicr);
+ rz_ssi_reg_writel(ssi, SSIFCR, ssifcr);
+
+ /* Clear all error flags */
+ rz_ssi_reg_mask_setl(ssi, SSISR,
+ (SSISR_TOIRQ | SSISR_TUIRQ | SSISR_ROIRQ |
+ SSISR_RUIRQ), 0);
+
+ strm->running = 1;
+ ssicr |= is_play ? SSICR_TEN : SSICR_REN;
+ rz_ssi_reg_writel(ssi, SSICR, ssicr);
+
+ return 0;
+}
+
+static int rz_ssi_stop(struct rz_ssi_priv *ssi, struct rz_ssi_stream *strm)
+{
+ int timeout;
+
+ strm->running = 0;
+
+ /* Disable TX/RX */
+ rz_ssi_reg_mask_setl(ssi, SSICR, SSICR_TEN | SSICR_REN, 0);
+
+ /* Disable irqs */
+ rz_ssi_reg_mask_setl(ssi, SSICR, SSICR_TUIEN | SSICR_TOIEN |
+ SSICR_RUIEN | SSICR_ROIEN, 0);
+ rz_ssi_reg_mask_setl(ssi, SSIFCR, SSIFCR_TIE | SSIFCR_RIE, 0);
+
+ /* Clear all error flags */
+ rz_ssi_reg_mask_setl(ssi, SSISR,
+ (SSISR_TOIRQ | SSISR_TUIRQ | SSISR_ROIRQ |
+ SSISR_RUIRQ), 0);
+
+ /* Wait for idle */
+ timeout = 100;
+ while (--timeout) {
+ if (rz_ssi_reg_readl(ssi, SSISR) | SSISR_IIRQ)
+ break;
+ udelay(1);
+ }
+
+ if (!timeout)
+ dev_info(ssi->dev, "timeout waiting for SSI idle\n");
+
+ /* Hold FIFOs in reset */
+ rz_ssi_reg_mask_setl(ssi, SSIFCR, 0,
+ SSIFCR_TFRST | SSIFCR_RFRST);
+
+ return 0;
+}
+
+static void rz_ssi_pointer_update(struct rz_ssi_stream *strm, int frames)
+{
+ struct snd_pcm_substream *substream = strm->substream;
+ struct snd_pcm_runtime *runtime;
+ int current_period;
+
+ if (!strm->running || !substream || !substream->runtime)
+ return;
+
+ runtime = substream->runtime;
+ strm->buffer_pos += frames;
+ WARN_ON(strm->buffer_pos > runtime->buffer_size);
+
+ /* ring buffer */
+ if (strm->buffer_pos == runtime->buffer_size)
+ strm->buffer_pos = 0;
+
+ current_period = strm->buffer_pos / runtime->period_size;
+ if (strm->period_counter != current_period) {
+ snd_pcm_period_elapsed(strm->substream);
+ strm->period_counter = current_period;
+ }
+}
+
+static int rz_ssi_pio_recv(struct rz_ssi_priv *ssi, struct rz_ssi_stream *strm)
+{
+ struct snd_pcm_substream *substream = strm->substream;
+ struct snd_pcm_runtime *runtime;
+ u16 *buf;
+ int fifo_samples;
+ int frames_left;
+ int samples = 0;
+ int i;
+
+ if (!rz_ssi_stream_is_valid(ssi, strm))
+ return -EINVAL;
+
+ runtime = substream->runtime;
+ /* frames left in this period */
+ frames_left = runtime->period_size - (strm->buffer_pos %
+ runtime->period_size);
+ if (frames_left == 0)
+ frames_left = runtime->period_size;
+
+ /* Samples in RX FIFO */
+ fifo_samples = (rz_ssi_reg_readl(ssi, SSIFSR) >>
+ SSIFSR_RDC_SHIFT) & SSIFSR_RDC_MASK;
+
+ /* Only read full frames at a time */
+ while (frames_left && (fifo_samples >= runtime->channels)) {
+ samples += runtime->channels;
+ fifo_samples -= runtime->channels;
+ frames_left--;
+ }
+
+ /* not enough samples yet */
+ if (samples == 0)
+ return 0;
+
+ /* calculate new buffer index */
+ buf = (u16 *)(runtime->dma_area);
+ buf += strm->buffer_pos * runtime->channels;
+
+ /* Note, only supports 16-bit samples */
+ for (i = 0; i < samples; i++)
+ *buf++ = (u16)(rz_ssi_reg_readl(ssi, SSIFRDR) >> 16);
+
+ rz_ssi_reg_mask_setl(ssi, SSIFSR, SSIFSR_RDF, 0);
+ rz_ssi_pointer_update(strm, samples / runtime->channels);
+
+ /*
+ * If we finished this period, but there are more samples in
+ * the RX FIFO, call this function again
+ */
+ if (frames_left == 0 && fifo_samples >= runtime->channels)
+ rz_ssi_pio_recv(ssi, strm);
+
+ return 0;
+}
+
+static int rz_ssi_pio_send(struct rz_ssi_priv *ssi, struct rz_ssi_stream *strm)
+{
+ struct snd_pcm_substream *substream = strm->substream;
+ struct snd_pcm_runtime *runtime = substream->runtime;
+ int sample_space;
+ int samples = 0;
+ int frames_left;
+ int i;
+ u32 ssifsr;
+ u16 *buf;
+
+ if (!rz_ssi_stream_is_valid(ssi, strm))
+ return -EINVAL;
+
+ /* frames left in this period */
+ frames_left = runtime->period_size - (strm->buffer_pos %
+ runtime->period_size);
+ if (frames_left == 0)
+ frames_left = runtime->period_size;
+
+ sample_space = strm->fifo_sample_size;
+ ssifsr = rz_ssi_reg_readl(ssi, SSIFSR);
+ sample_space -= (ssifsr >> SSIFSR_TDC_SHIFT) & SSIFSR_TDC_MASK;
+
+ /* Only add full frames at a time */
+ while (frames_left && (sample_space >= runtime->channels)) {
+ samples += runtime->channels;
+ sample_space -= runtime->channels;
+ frames_left--;
+ }
+
+ /* no space to send anything right now */
+ if (samples == 0)
+ return 0;
+
+ /* calculate new buffer index */
+ buf = (u16 *)(runtime->dma_area);
+ buf += strm->buffer_pos * runtime->channels;
+
+ /* Note, only supports 16-bit samples */
+ for (i = 0; i < samples; i++)
+ rz_ssi_reg_writel(ssi, SSIFTDR, ((u32)(*buf++) << 16));
+
+ rz_ssi_reg_mask_setl(ssi, SSIFSR, SSIFSR_TDE, 0);
+ rz_ssi_pointer_update(strm, samples / runtime->channels);
+
+ return 0;
+}
+
+static irqreturn_t rz_ssi_interrupt(int irq, void *data)
+{
+ struct rz_ssi_stream *strm = NULL;
+ struct rz_ssi_priv *ssi = data;
+ u32 ssisr = rz_ssi_reg_readl(ssi, SSISR);
+
+ if (ssi->playback.substream)
+ strm = &ssi->playback;
+ else if (ssi->capture.substream)
+ strm = &ssi->capture;
+ else
+ return IRQ_HANDLED; /* Left over TX/RX interrupt */
+
+ if (irq == ssi->irq_int) { /* error or idle */
+ if (ssisr & SSISR_TUIRQ)
+ strm->uerr_num++;
+ if (ssisr & SSISR_TOIRQ)
+ strm->oerr_num++;
+ if (ssisr & SSISR_RUIRQ)
+ strm->uerr_num++;
+ if (ssisr & SSISR_ROIRQ)
+ strm->oerr_num++;
+
+ if (ssisr & (SSISR_TUIRQ | SSISR_TOIRQ | SSISR_RUIRQ |
+ SSISR_ROIRQ)) {
+ /* Error handling */
+ /* You must reset (stop/restart) after each interrupt */
+ rz_ssi_stop(ssi, strm);
+
+ /* Clear all flags */
+ rz_ssi_reg_mask_setl(ssi, SSISR, SSISR_TOIRQ |
+ SSISR_TUIRQ | SSISR_ROIRQ |
+ SSISR_RUIRQ, 0);
+
+ /* Add/remove more data */
+ strm->transfer(ssi, strm);
+
+ /* Resume */
+ rz_ssi_start(ssi, strm);
+ }
+ }
+
+ if (!strm->running)
+ return IRQ_HANDLED;
+
+ /* tx data empty */
+ if (irq == ssi->irq_tx)
+ strm->transfer(ssi, &ssi->playback);
+
+ /* rx data full */
+ if (irq == ssi->irq_rx) {
+ strm->transfer(ssi, &ssi->capture);
+ rz_ssi_reg_mask_setl(ssi, SSIFSR, SSIFSR_RDF, 0);
+ }
+
+ return IRQ_HANDLED;
+}
+
+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;
+
+ switch (cmd) {
+ case SNDRV_PCM_TRIGGER_START:
+ /* Soft Reset */
+ rz_ssi_reg_mask_setl(ssi, SSIFCR, 0, SSIFCR_SSIRST);
+ rz_ssi_reg_mask_setl(ssi, SSIFCR, SSIFCR_SSIRST, 0);
+ udelay(5);
+
+ ret = rz_ssi_stream_init(ssi, strm, substream);
+ if (ret)
+ goto done;
+
+ ret = strm->transfer(ssi, strm);
+ if (ret)
+ goto done;
+
+ ret = rz_ssi_start(ssi, strm);
+ break;
+ case SNDRV_PCM_TRIGGER_STOP:
+ rz_ssi_stop(ssi, strm);
+ rz_ssi_stream_quit(ssi, strm);
+ break;
+ }
+
+done:
+ return ret;
+}
+
+static int rz_ssi_dai_set_fmt(struct snd_soc_dai *dai, unsigned int fmt)
+{
+ struct rz_ssi_priv *ssi = snd_soc_dai_get_drvdata(dai);
+
+ switch (fmt & SND_SOC_DAIFMT_CLOCK_PROVIDER_MASK) {
+ case SND_SOC_DAIFMT_CBC_CFC:
+ break;
+ default:
+ dev_err(ssi->dev, "Codec should be clk and frame consumer\n");
+ return -EINVAL;
+ }
+
+ /*
+ * set clock polarity
+ *
+ * "normal" BCLK = Signal is available at rising edge of BCLK
+ * "normal" FSYNC = (I2S) Left ch starts with falling FSYNC edge
+ */
+ switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
+ case SND_SOC_DAIFMT_NB_NF:
+ ssi->bckp_rise = false;
+ ssi->lrckp_fsync_fall = false;
+ break;
+ case SND_SOC_DAIFMT_NB_IF:
+ ssi->bckp_rise = false;
+ ssi->lrckp_fsync_fall = true;
+ break;
+ case SND_SOC_DAIFMT_IB_NF:
+ ssi->bckp_rise = true;
+ ssi->lrckp_fsync_fall = false;
+ break;
+ case SND_SOC_DAIFMT_IB_IF:
+ ssi->bckp_rise = true;
+ ssi->lrckp_fsync_fall = true;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ /* only i2s support */
+ switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
+ case SND_SOC_DAIFMT_I2S:
+ break;
+ default:
+ dev_err(ssi->dev, "Only I2S mode is supported.\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int rz_ssi_dai_hw_params(struct snd_pcm_substream *substream,
+ struct snd_pcm_hw_params *params,
+ struct snd_soc_dai *dai)
+{
+ struct rz_ssi_priv *ssi = snd_soc_dai_get_drvdata(dai);
+ unsigned int sample_bits = hw_param_interval(params,
+ SNDRV_PCM_HW_PARAM_SAMPLE_BITS)->min;
+ unsigned int channels = params_channels(params);
+
+ if (sample_bits != 16) {
+ dev_err(ssi->dev, "Unsupported sample width: %d\n",
+ sample_bits);
+ return -EINVAL;
+ }
+
+ if (channels != 2) {
+ dev_err(ssi->dev, "Number of channels not matched: %d\n",
+ channels);
+ return -EINVAL;
+ }
+
+ return rz_ssi_clk_setup(ssi, params_rate(params),
+ params_channels(params));
+}
+
+static const struct snd_soc_dai_ops rz_ssi_dai_ops = {
+ .trigger = rz_ssi_dai_trigger,
+ .set_fmt = rz_ssi_dai_set_fmt,
+ .hw_params = rz_ssi_dai_hw_params,
+};
+
+static const struct snd_pcm_hardware rz_ssi_pcm_hardware = {
+ .info = SNDRV_PCM_INFO_INTERLEAVED |
+ SNDRV_PCM_INFO_MMAP |
+ SNDRV_PCM_INFO_MMAP_VALID,
+ .buffer_bytes_max = PREALLOC_BUFFER,
+ .period_bytes_min = 32,
+ .period_bytes_max = 8192,
+ .channels_min = SSI_CHAN_MIN,
+ .channels_max = SSI_CHAN_MAX,
+ .periods_min = 1,
+ .periods_max = 32,
+ .fifo_size = 32 * 2,
+};
+
+static int rz_ssi_pcm_open(struct snd_soc_component *component,
+ struct snd_pcm_substream *substream)
+{
+ snd_soc_set_runtime_hwparams(substream, &rz_ssi_pcm_hardware);
+
+ return snd_pcm_hw_constraint_integer(substream->runtime,
+ SNDRV_PCM_HW_PARAM_PERIODS);
+}
+
+static snd_pcm_uframes_t rz_ssi_pcm_pointer(struct snd_soc_component *component,
+ struct snd_pcm_substream *substream)
+{
+ struct snd_soc_dai *dai = rz_ssi_get_dai(substream);
+ struct rz_ssi_priv *ssi = snd_soc_dai_get_drvdata(dai);
+ struct rz_ssi_stream *strm = rz_ssi_stream_get(ssi, substream);
+
+ return strm->buffer_pos;
+}
+
+static int rz_ssi_pcm_new(struct snd_soc_component *component,
+ struct snd_soc_pcm_runtime *rtd)
+{
+ snd_pcm_set_managed_buffer_all(rtd->pcm, SNDRV_DMA_TYPE_DEV,
+ rtd->card->snd_card->dev,
+ PREALLOC_BUFFER, PREALLOC_BUFFER_MAX);
+ return 0;
+}
+
+static struct snd_soc_dai_driver rz_ssi_soc_dai[] = {
+ {
+ .name = "rz-ssi-dai",
+ .playback = {
+ .rates = SSI_RATES,
+ .formats = SSI_FMTS,
+ .channels_min = SSI_CHAN_MIN,
+ .channels_max = SSI_CHAN_MAX,
+ },
+ .capture = {
+ .rates = SSI_RATES,
+ .formats = SSI_FMTS,
+ .channels_min = SSI_CHAN_MIN,
+ .channels_max = SSI_CHAN_MAX,
+ },
+ .ops = &rz_ssi_dai_ops,
+ },
+};
+
+static const struct snd_soc_component_driver rz_ssi_soc_component = {
+ .name = "rz-ssi",
+ .open = rz_ssi_pcm_open,
+ .pointer = rz_ssi_pcm_pointer,
+ .pcm_construct = rz_ssi_pcm_new,
+};
+
+static int rz_ssi_probe(struct platform_device *pdev)
+{
+ struct rz_ssi_priv *ssi;
+ struct clk *audio_clk;
+ int ret;
+
+ ssi = devm_kzalloc(&pdev->dev, sizeof(*ssi), GFP_KERNEL);
+ if (!ssi)
+ return -ENOMEM;
+
+ ssi->pdev = pdev;
+ ssi->dev = &pdev->dev;
+ ssi->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(ssi->base))
+ return PTR_ERR(ssi->base);
+
+ ssi->clk = devm_clk_get(&pdev->dev, "ssi");
+ if (IS_ERR(ssi->clk))
+ return PTR_ERR(ssi->clk);
+
+ ssi->sfr_clk = devm_clk_get(&pdev->dev, "ssi_sfr");
+ if (IS_ERR(ssi->sfr_clk))
+ return PTR_ERR(ssi->sfr_clk);
+
+ audio_clk = devm_clk_get(&pdev->dev, "audio_clk1");
+ if (IS_ERR(audio_clk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(audio_clk),
+ "no audio clk1");
+
+ ssi->audio_clk_1 = clk_get_rate(audio_clk);
+ audio_clk = devm_clk_get(&pdev->dev, "audio_clk2");
+ if (IS_ERR(audio_clk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(audio_clk),
+ "no audio clk2");
+
+ ssi->audio_clk_2 = clk_get_rate(audio_clk);
+ if (!(ssi->audio_clk_1 || ssi->audio_clk_2))
+ return dev_err_probe(&pdev->dev, -EINVAL,
+ "no audio clk1 or audio clk2");
+
+ 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;
+ ssi->playback.priv = ssi;
+ ssi->capture.priv = ssi;
+
+ /* Error Interrupt */
+ ssi->irq_int = platform_get_irq_byname(pdev, "int_req");
+ if (ssi->irq_int < 0)
+ return dev_err_probe(&pdev->dev, -ENODEV,
+ "Unable to get SSI int_req IRQ\n");
+
+ ret = devm_request_irq(&pdev->dev, ssi->irq_int, &rz_ssi_interrupt,
+ 0, dev_name(&pdev->dev), ssi);
+ if (ret < 0)
+ 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");
+
+ ssi->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+ if (IS_ERR(ssi->rstc))
+ return PTR_ERR(ssi->rstc);
+
+ reset_control_deassert(ssi->rstc);
+ pm_runtime_enable(&pdev->dev);
+ pm_runtime_resume_and_get(&pdev->dev);
+
+ spin_lock_init(&ssi->lock);
+ dev_set_drvdata(&pdev->dev, ssi);
+ ret = devm_snd_soc_register_component(&pdev->dev, &rz_ssi_soc_component,
+ rz_ssi_soc_dai,
+ ARRAY_SIZE(rz_ssi_soc_dai));
+ if (ret < 0) {
+ pm_runtime_put(ssi->dev);
+ pm_runtime_disable(ssi->dev);
+ reset_control_assert(ssi->rstc);
+ dev_err(&pdev->dev, "failed to register snd component\n");
+ }
+
+ return ret;
+}
+
+static int rz_ssi_remove(struct platform_device *pdev)
+{
+ struct rz_ssi_priv *ssi = dev_get_drvdata(&pdev->dev);
+
+ pm_runtime_put(ssi->dev);
+ pm_runtime_disable(ssi->dev);
+ reset_control_assert(ssi->rstc);
+
+ return 0;
+}
+
+static const struct of_device_id rz_ssi_of_match[] = {
+ { .compatible = "renesas,rz-ssi", },
+ {/* Sentinel */},
+};
+MODULE_DEVICE_TABLE(of, rz_ssi_of_match);
+
+static struct platform_driver rz_ssi_driver = {
+ .driver = {
+ .name = "rz-ssi-pcm-audio",
+ .of_match_table = rz_ssi_of_match,
+ },
+ .probe = rz_ssi_probe,
+ .remove = rz_ssi_remove,
+};
+
+module_platform_driver(rz_ssi_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Renesas RZ/G2L ASoC Serial Sound Interface Driver");
+MODULE_AUTHOR("Biju Das <biju.das.jz@bp.renesas.com>");
--
2.17.1


Pavel Machek
 

Hi!

From: Biju Das <biju.das.jz@bp.renesas.com>

commit 03e786bd43410fa93e5d2459f7a43e90ff0ae801 upstream.

Add serial sound interface(SSIF-2) driver support for
RZ/G2L SoC.

Based on the work done by Chris Brandt for RZ/A SSI driver.
I'm not sure what the locking rules are here.

--- /dev/null
+++ b/sound/soc/sh/rz-ssi.c
+static int rz_ssi_stream_is_valid(struct rz_ssi_priv *ssi,
+ struct rz_ssi_stream *strm)
+{
+ unsigned long flags;
+ int ret;
+
+ spin_lock_irqsave(&ssi->lock, flags);
+ ret = !!(strm->substream && strm->substream->runtime);
+ spin_unlock_irqrestore(&ssi->lock, flags);
+
+ return ret;
+}
Nit: I don't think !!() is useful here, as it is boolean expression
anyway.

But I notice that code is very careful to access strm->substream with
spinlock held.

+static void rz_ssi_pointer_update(struct rz_ssi_stream *strm, int frames)
+{
+ struct snd_pcm_substream *substream = strm->substream;
+ struct snd_pcm_runtime *runtime;
+ int current_period;
+
+ if (!strm->running || !substream || !substream->runtime)
+ return;
But here we do same checks, and this time without the spinlock?

+static int rz_ssi_pio_recv(struct rz_ssi_priv *ssi, struct rz_ssi_stream *strm)
+{
+ struct snd_pcm_substream *substream = strm->substream;
+ struct snd_pcm_runtime *runtime;
+ u16 *buf;
+ int fifo_samples;
+ int frames_left;
+ int samples = 0;
+ int i;
+
+ if (!rz_ssi_stream_is_valid(ssi, strm))
+ return -EINVAL;
+
+ runtime = substream->runtime;
Again, access without locking.

+ /*
+ * If we finished this period, but there are more samples in
+ * the RX FIFO, call this function again
+ */
+ if (frames_left == 0 && fifo_samples >= runtime->channels)
+ rz_ssi_pio_recv(ssi, strm);
Here we call ourselves recurively. Without checking the return
value.. but more importantly recursion is unwelcome in kernel due to
limited stack use.


+static int rz_ssi_pio_send(struct rz_ssi_priv *ssi, struct rz_ssi_stream *strm)
+{
+ struct snd_pcm_substream *substream = strm->substream;
+ struct snd_pcm_runtime *runtime = substream->runtime;
+ int sample_space;
+ int samples = 0;
+ int frames_left;
+ int i;
+ u32 ssifsr;
+ u16 *buf;
+
+ if (!rz_ssi_stream_is_valid(ssi, strm))
+ return -EINVAL;
Access without locking before verifying that stream is valid with the
lock. This is wrong.

+static irqreturn_t rz_ssi_interrupt(int irq, void *data)
+{
+ struct rz_ssi_stream *strm = NULL;
+ struct rz_ssi_priv *ssi = data;
+ u32 ssisr = rz_ssi_reg_readl(ssi, SSISR);
+
+ if (ssi->playback.substream)
+ strm = &ssi->playback;
+ else if (ssi->capture.substream)
+ strm = &ssi->capture;
+ else
+ return IRQ_HANDLED; /* Left over TX/RX interrupt */
You mark interrupt as handled even when it is not. Probably not a
problem w/o shared interrupts.

+static int rz_ssi_probe(struct platform_device *pdev)
+{
...
+ /* Error Interrupt */
+ ssi->irq_int = platform_get_irq_byname(pdev, "int_req");
+ if (ssi->irq_int < 0)
+ return dev_err_probe(&pdev->dev, -ENODEV,
+ "Unable to get SSI int_req IRQ\n");
+
+ ret = devm_request_irq(&pdev->dev, ssi->irq_int, &rz_ssi_interrupt,
+ 0, dev_name(&pdev->dev), ssi);
+ if (ret < 0)
+ 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");
...

So you registered interrupt handlers...

+
+ 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))
+ return PTR_ERR(ssi->rstc);
+
+ reset_control_deassert(ssi->rstc);
+ pm_runtime_enable(&pdev->dev);
+ pm_runtime_resume_and_get(&pdev->dev);
+
+ spin_lock_init(&ssi->lock);
+ dev_set_drvdata(&pdev->dev, ssi);
But only here you have data structures ready to handle the
interrupts. You won't see obvious problems w/o shared interrupts, but
I believe there are debugging modes that trigger this intentionally.

Best regards,
Pavel
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany


Lad Prabhakar
 

Hi Pavel,

Thank you for the review.

-----Original Message-----
From: Pavel Machek <pavel@denx.de>
Sent: 30 December 2021 11:15
To: Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>
Cc: cip-dev@lists.cip-project.org; Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>; Pavel Machek
<pavel@denx.de>; Biju Das <biju.das.jz@bp.renesas.com>
Subject: Re: [PATCH 5.10.y-cip 03/31] ASoC: sh: Add RZ/G2L SSIF-2 driver

Hi!

From: Biju Das <biju.das.jz@bp.renesas.com>

commit 03e786bd43410fa93e5d2459f7a43e90ff0ae801 upstream.

Add serial sound interface(SSIF-2) driver support for RZ/G2L SoC.

Based on the work done by Chris Brandt for RZ/A SSI driver.
I'm not sure what the locking rules are here.

--- /dev/null
+++ b/sound/soc/sh/rz-ssi.c
+static int rz_ssi_stream_is_valid(struct rz_ssi_priv *ssi,
+ struct rz_ssi_stream *strm)
+{
+ unsigned long flags;
+ int ret;
+
+ spin_lock_irqsave(&ssi->lock, flags);
+ ret = !!(strm->substream && strm->substream->runtime);
+ spin_unlock_irqrestore(&ssi->lock, flags);
+
+ return ret;
+}
Nit: I don't think !!() is useful here, as it is boolean expression anyway.
Agreed can be dropped.

But I notice that code is very careful to access strm->substream with spinlock held.
...
+static void rz_ssi_pointer_update(struct rz_ssi_stream *strm, int
+frames) {
+ struct snd_pcm_substream *substream = strm->substream;
+ struct snd_pcm_runtime *runtime;
+ int current_period;
+
+ if (!strm->running || !substream || !substream->runtime)
+ return;
But here we do same checks, and this time without the spinlock?
... agree we need to lock...
+static int rz_ssi_pio_recv(struct rz_ssi_priv *ssi, struct
+rz_ssi_stream *strm) {
+ struct snd_pcm_substream *substream = strm->substream;
+ struct snd_pcm_runtime *runtime;
+ u16 *buf;
+ int fifo_samples;
+ int frames_left;
+ int samples = 0;
+ int i;
+
+ if (!rz_ssi_stream_is_valid(ssi, strm))
+ return -EINVAL;
+
+ runtime = substream->runtime;
Again, access without locking.
... and here too.

+ /*
+ * If we finished this period, but there are more samples in
+ * the RX FIFO, call this function again
+ */
+ if (frames_left == 0 && fifo_samples >= runtime->channels)
+ rz_ssi_pio_recv(ssi, strm);
Here we call ourselves recurively. Without checking the return value.. but more importantly recursion
is unwelcome in kernel due to limited stack use.

Agreed, this needs to be handled differently with recursion removed.

+static int rz_ssi_pio_send(struct rz_ssi_priv *ssi, struct
+rz_ssi_stream *strm) {
+ struct snd_pcm_substream *substream = strm->substream;
+ struct snd_pcm_runtime *runtime = substream->runtime;
+ int sample_space;
+ int samples = 0;
+ int frames_left;
+ int i;
+ u32 ssifsr;
+ u16 *buf;
+
+ if (!rz_ssi_stream_is_valid(ssi, strm))
+ return -EINVAL;
Access without locking before verifying that stream is valid with the lock. This is wrong.
rz_ssi_stream_is_valid() does lock/unlock to check stream validity.

+static irqreturn_t rz_ssi_interrupt(int irq, void *data) {
+ struct rz_ssi_stream *strm = NULL;
+ struct rz_ssi_priv *ssi = data;
+ u32 ssisr = rz_ssi_reg_readl(ssi, SSISR);
+
+ if (ssi->playback.substream)
+ strm = &ssi->playback;
+ else if (ssi->capture.substream)
+ strm = &ssi->capture;
+ else
+ return IRQ_HANDLED; /* Left over TX/RX interrupt */
You mark interrupt as handled even when it is not. Probably not a problem w/o shared interrupts.
ATM the interrupts aren't shared so this should be OK.

+static int rz_ssi_probe(struct platform_device *pdev) {
...
+ /* Error Interrupt */
+ ssi->irq_int = platform_get_irq_byname(pdev, "int_req");
+ if (ssi->irq_int < 0)
+ return dev_err_probe(&pdev->dev, -ENODEV,
+ "Unable to get SSI int_req IRQ\n");
+
+ ret = devm_request_irq(&pdev->dev, ssi->irq_int, &rz_ssi_interrupt,
+ 0, dev_name(&pdev->dev), ssi);
+ if (ret < 0)
+ 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");
...

So you registered interrupt handlers...

+
+ 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))
+ return PTR_ERR(ssi->rstc);
+
+ reset_control_deassert(ssi->rstc);
+ pm_runtime_enable(&pdev->dev);
+ pm_runtime_resume_and_get(&pdev->dev);
+
+ spin_lock_init(&ssi->lock);
+ dev_set_drvdata(&pdev->dev, ssi);
But only here you have data structures ready to handle the interrupts. You won't see obvious problems
w/o shared interrupts, but I believe there are debugging modes that trigger this intentionally.
But the devm_snd_soc_register_component() is after this so it should be OK I believe unless there is a spurious interrupt which will trigger the handler.

Cheers,
Prabhakar


Pavel Machek
 

Hi!

+static int rz_ssi_pio_send(struct rz_ssi_priv *ssi, struct
+rz_ssi_stream *strm) {
+ struct snd_pcm_substream *substream = strm->substream;
+ struct snd_pcm_runtime *runtime = substream->runtime;
+ int sample_space;
+ int samples = 0;
+ int frames_left;
+ int i;
+ u32 ssifsr;
+ u16 *buf;
+
+ if (!rz_ssi_stream_is_valid(ssi, strm))
+ return -EINVAL;
Access without locking before verifying that stream is valid with the lock. This is wrong.
rz_ssi_stream_is_valid() does lock/unlock to check stream validity.
Yes, but "struct snd_pcm_runtime *runtime = substream->runtime" above
already accessed that data without locking.

+static int rz_ssi_probe(struct platform_device *pdev) {
...
+ /* Error Interrupt */
+ ssi->irq_int = platform_get_irq_byname(pdev, "int_req");
+ if (ssi->irq_int < 0)
+ return dev_err_probe(&pdev->dev, -ENODEV,
+ "Unable to get SSI int_req IRQ\n");
+
+ ret = devm_request_irq(&pdev->dev, ssi->irq_int, &rz_ssi_interrupt,
+ 0, dev_name(&pdev->dev), ssi);
+ if (ret < 0)
+ 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");
...

So you registered interrupt handlers...

+
+ 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))
+ return PTR_ERR(ssi->rstc);
+
+ reset_control_deassert(ssi->rstc);
+ pm_runtime_enable(&pdev->dev);
+ pm_runtime_resume_and_get(&pdev->dev);
+
+ spin_lock_init(&ssi->lock);
+ dev_set_drvdata(&pdev->dev, ssi);
But only here you have data structures ready to handle the interrupts. You won't see obvious problems
w/o shared interrupts, but I believe there are debugging modes that trigger this intentionally.
But the devm_snd_soc_register_component() is after this so it should be OK I believe unless there is a spurious interrupt which will trigger the handler.
I believe your code will do fine in usual configurations. But
reordering it should be quite easy, and there are kernel options like
"irqpoll", "irqfixup" and CONFIG_DEBUG_SHIRQ.

Best regards,
Pavel
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