greybus: gb-audio: Add integrated greybus audio driver
So here's the current greybus audio driver, which I
wanted to send out for more serious review and
consideration for merging.
I've tried to integrate much of the feedback from the
last round and most of the hotplug issues that I've found
have been resolved. I've tested this via gbsim, and the
Android ARA HAL layer seems to work with it.
Mark has also successfully played audio with this driver,
adding a few hacks to get the codec's i2c connection to
probe.
Current issues:
* Hotplug problem - When gbsim is killed, or the module
removed, the greybus driver gets stuck since the android
mediaserver process is holding the audio device open.
Killing the mediaserver allows things to clean up and
allows greybus to accept new gbsim connections. I have
a workaround patch to the soc-core.c logic which converts
the snd_card_free() call to snd_card_free_when_closed()
which allows the greybus connection cleanup to finish.
Remaining todos:
* Probably need to break apart the mgmt_setup function
to integrate better with the constraint logic. I took
a really basic stab at this, but more is probably
needed.
* Figure out how to properly find and tie in the
codec's I2C bus-id to the driver.
This code requires that the kernel support the following
config options, which I've enabled in a separate kernel
patch:
CONFIG_SND_SIMPLE_CARD
CONFIG_SND_SOC_SPDIF
CONFIG_SND_SOC_RT5645
I really can't calim to be the sole author of this, since
many many fixes and tweaks that have been folded in have
come from Mark Greer. His analsysis and debugging is really
what has made this dummy-framework driver evolve into an
actual audio driver. So much credit and thanks to Mark!
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
diff --git a/drivers/staging/greybus/audio-pcm.c b/drivers/staging/greybus/audio-pcm.c
new file mode 100644
index 0000000..28b5e11
--- /dev/null
+++ b/drivers/staging/greybus/audio-pcm.c
@@ -0,0 +1,262 @@
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/workqueue.h>
+#include <linux/i2c.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+#include <sound/dmaengine_pcm.h>
+#include <sound/simple_card.h>
+#include "greybus.h"
+#include "gpbridge.h"
+#include "audio.h"
+
+/*
+ * timer/workqueue logic for pushing pcm data.
+ *
+ * Since when we are playing audio, we don't get any
+ * status or feedback from the codec, we have to use a
+ * hrtimer to trigger sending data to the remote codec.
+ * However since the hrtimer runs in irq context, so we
+ * have to schedule a workqueue to actually send the
+ * greybus data.
+ */
+
+static void gb_pcm_work(struct work_struct *work)
+{
+ struct gb_snd *snd_dev = container_of(work, struct gb_snd, work);
+ struct snd_pcm_substream *substream = snd_dev->substream;
+ struct snd_pcm_runtime *runtime = substream->runtime;
+ unsigned int stride, frames, oldptr;
+ int period_elapsed;
+ char *address;
+ long len;
+
+ if (!snd_dev)
+ return;
+
+ if (!atomic_read(&snd_dev->running))
+ return;
+
+ address = runtime->dma_area + snd_dev->hwptr_done;
+
+ len = frames_to_bytes(runtime,
+ runtime->buffer_size) - snd_dev->hwptr_done;
+ len = min(len, MAX_SEND_DATA_LEN);
+ gb_i2s_send_data(snd_dev->i2s_tx_connection, snd_dev->send_data_req_buf,
+ address, len, snd_dev->send_data_sample_count);
+
+ snd_dev->send_data_sample_count += CONFIG_SAMPLES_PER_MSG;
+
+ stride = runtime->frame_bits >> 3;
+ frames = len/stride;
+
+ snd_pcm_stream_lock(substream);
+ oldptr = snd_dev->hwptr_done;
+ snd_dev->hwptr_done += len;
+ if (snd_dev->hwptr_done >= runtime->buffer_size * stride)
+ snd_dev->hwptr_done -= runtime->buffer_size * stride;
+
+ frames = (len + (oldptr % stride)) / stride;
+
+ snd_dev->transfer_done += frames;
+ if (snd_dev->transfer_done >= runtime->period_size) {
+ snd_dev->transfer_done -= runtime->period_size;
+ period_elapsed = 1;
+ }
+
+ snd_pcm_stream_unlock(substream);
+ if (period_elapsed)
+ snd_pcm_period_elapsed(snd_dev->substream);
+}
+
+static enum hrtimer_restart gb_pcm_timer_function(struct hrtimer *hrtimer)
+{
+ struct gb_snd *snd_dev = container_of(hrtimer, struct gb_snd, timer);
+
+ if (!atomic_read(&snd_dev->running))
+ return HRTIMER_NORESTART;
+ queue_work(snd_dev->workqueue, &snd_dev->work);
+ hrtimer_forward_now(hrtimer, ns_to_ktime(CONFIG_PERIOD_NS));
+ return HRTIMER_RESTART;
+}
+
+void gb_pcm_hrtimer_start(struct gb_snd *snd_dev)
+{
+ atomic_set(&snd_dev->running, 1);
+ hrtimer_start(&snd_dev->timer, ns_to_ktime(CONFIG_PERIOD_NS),
+ HRTIMER_MODE_REL);
+}
+
+void gb_pcm_hrtimer_stop(struct gb_snd *snd_dev)
+{
+ atomic_set(&snd_dev->running, 0);
+ hrtimer_cancel(&snd_dev->timer);
+}
+
+static int gb_pcm_hrtimer_init(struct gb_snd *snd_dev)
+{
+ hrtimer_init(&snd_dev->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ snd_dev->timer.function = gb_pcm_timer_function;
+ atomic_set(&snd_dev->running, 0);
+ snd_dev->workqueue = alloc_workqueue("gb-audio", WQ_HIGHPRI, 0);
+ if (!snd_dev->workqueue)
+ return -ENOMEM;
+ INIT_WORK(&snd_dev->work, gb_pcm_work);
+ return 0;
+}
+
+
+/*
+ * Core gb pcm structure
+ */
+static struct snd_pcm_hardware gb_plat_pcm_hardware = {
+ .info = SNDRV_PCM_INFO_INTERLEAVED |
+ SNDRV_PCM_INFO_MMAP |
+ SNDRV_PCM_INFO_MMAP_VALID,
+ .formats = GB_FMTS,
+ .rates = GB_RATES,
+ .rate_min = 8000,
+ .rate_max = GB_SAMPLE_RATE,
+ .channels_min = 1,
+ .channels_max = 2,
+ /* XXX - All the values below are junk */
+ .buffer_bytes_max = 64 * 1024,
+ .period_bytes_min = 32,
+ .period_bytes_max = 8192,
+ .periods_min = 2,
+ .periods_max = 32,
+};
+
+static snd_pcm_uframes_t gb_pcm_pointer(struct snd_pcm_substream *substream)
+{
+ struct snd_soc_pcm_runtime *rtd = substream->private_data;
+ struct gb_snd *snd_dev;
+
+ snd_dev = snd_soc_dai_get_drvdata(rtd->cpu_dai);
+
+ return snd_dev->hwptr_done / (substream->runtime->frame_bits >> 3);
+}
+
+static int gb_pcm_prepare(struct snd_pcm_substream *substream)
+{
+ struct snd_soc_pcm_runtime *rtd = substream->private_data;
+ struct gb_snd *snd_dev;
+
+ snd_dev = snd_soc_dai_get_drvdata(rtd->cpu_dai);
+ snd_dev->hwptr_done = 0;
+ snd_dev->transfer_done = 0;
+ return 0;
+}
+
+static unsigned int rates[] = {GB_SAMPLE_RATE};
+static struct snd_pcm_hw_constraint_list constraints_rates = {
+ .count = ARRAY_SIZE(rates),
+ .list = rates,
+ .mask = 0,
+};
+
+static int gb_pcm_open(struct snd_pcm_substream *substream)
+{
+ struct snd_pcm_runtime *runtime = substream->runtime;
+ struct snd_soc_pcm_runtime *rtd = substream->private_data;
+ struct gb_snd *snd_dev;
+ unsigned long flags;
+ int ret;
+
+ snd_dev = snd_soc_dai_get_drvdata(rtd->cpu_dai);
+
+ spin_lock_irqsave(&snd_dev->lock, flags);
+ runtime->private_data = snd_dev;
+ snd_dev->substream = substream;
+ ret = gb_pcm_hrtimer_init(snd_dev);
+ spin_unlock_irqrestore(&snd_dev->lock, flags);
+
+ if (ret)
+ return ret;
+
+ snd_soc_set_runtime_hwparams(substream, &gb_plat_pcm_hardware);
+
+ ret = snd_pcm_hw_constraint_list(substream->runtime, 0,
+ SNDRV_PCM_HW_PARAM_RATE,
+ &constraints_rates);
+ if (ret < 0)
+ return ret;
+
+ return snd_pcm_hw_constraint_integer(runtime,
+ SNDRV_PCM_HW_PARAM_PERIODS);
+}
+
+static int gb_pcm_close(struct snd_pcm_substream *substream)
+{
+ substream->runtime->private_data = NULL;
+ return 0;
+}
+
+static int gb_pcm_hw_params(struct snd_pcm_substream *substream,
+ struct snd_pcm_hw_params *hw_params)
+{
+ return snd_pcm_lib_malloc_pages(substream,
+ params_buffer_bytes(hw_params));
+}
+
+static int gb_pcm_hw_free(struct snd_pcm_substream *substream)
+{
+ return snd_pcm_lib_free_pages(substream);
+}
+
+static struct snd_pcm_ops gb_pcm_ops = {
+ .open = gb_pcm_open,
+ .close = gb_pcm_close,
+ .ioctl = snd_pcm_lib_ioctl,
+ .hw_params = gb_pcm_hw_params,
+ .hw_free = gb_pcm_hw_free,
+ .prepare = gb_pcm_prepare,
+ .pointer = gb_pcm_pointer,
+};
+
+static void gb_pcm_free(struct snd_pcm *pcm)
+{
+ snd_pcm_lib_preallocate_free_for_all(pcm);
+}
+
+static int gb_pcm_new(struct snd_soc_pcm_runtime *rtd)
+{
+ struct snd_pcm *pcm = rtd->pcm;
+
+ return snd_pcm_lib_preallocate_pages_for_all(
+ pcm,
+ SNDRV_DMA_TYPE_CONTINUOUS,
+ snd_dma_continuous_data(GFP_KERNEL),
+ PREALLOC_BUFFER, PREALLOC_BUFFER_MAX);
+}
+
+struct snd_soc_platform_driver gb_soc_platform = {
+ .ops = &gb_pcm_ops,
+ .pcm_new = gb_pcm_new,
+ .pcm_free = gb_pcm_free,
+};
+
+static int gb_soc_platform_probe(struct platform_device *pdev)
+{
+ return snd_soc_register_platform(&pdev->dev, &gb_soc_platform);
+}
+
+static int gb_soc_platform_remove(struct platform_device *pdev)
+{
+ snd_soc_unregister_platform(&pdev->dev);
+ return 0;
+}
+
+struct platform_driver gb_audio_pcm_driver = {
+ .driver = {
+ .name = "gb-pcm-audio",
+ .owner = THIS_MODULE,
+ },
+ .probe = gb_soc_platform_probe,
+ .remove = gb_soc_platform_remove,
+};