diff options
Diffstat (limited to 'sound/usb/usx2y/us144mkii_pcm.h')
| -rw-r--r-- | sound/usb/usx2y/us144mkii_pcm.h | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/sound/usb/usx2y/us144mkii_pcm.h b/sound/usb/usx2y/us144mkii_pcm.h new file mode 100644 index 000000000000..74da8564431b --- /dev/null +++ b/sound/usb/usx2y/us144mkii_pcm.h @@ -0,0 +1,165 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +// Copyright (c) 2025 Šerif Rami <ramiserifpersia@gmail.com> + +#ifndef __US144MKII_PCM_H +#define __US144MKII_PCM_H + +#include "us144mkii.h" + +/** + * tascam_pcm_hw - Hardware capabilities for TASCAM US-144MKII PCM. + * + * Defines the supported PCM formats, rates, channels, and buffer/period sizes + * for the TASCAM US-144MKII audio interface. + */ +extern const struct snd_pcm_hardware tascam_pcm_hw; + +/** + * tascam_playback_ops - ALSA PCM operations for playback. + * + * This structure defines the callback functions for playback stream operations. + */ +extern const struct snd_pcm_ops tascam_playback_ops; + +/** + * tascam_capture_ops - ALSA PCM operations for capture. + * + * This structure defines the callback functions for capture stream operations. + */ +extern const struct snd_pcm_ops tascam_capture_ops; + +/** + * playback_urb_complete() - Completion handler for playback isochronous URBs. + * @urb: the completed URB + * + * This function runs in interrupt context. It calculates the number of bytes + * to send in the next set of packets based on the feedback-driven clock, + * copies the audio data from the ALSA ring buffer, and resubmits the URB. + */ +void playback_urb_complete(struct urb *urb); + +/** + * feedback_urb_complete() - Completion handler for feedback isochronous URBs. + * @urb: the completed URB + * + * This is the master clock for the driver. It runs in interrupt context. + * It reads the feedback value from the device, which indicates how many + * samples the device has consumed. This information is used to adjust the + * playback rate and to advance the capture stream pointer, keeping both + * streams in sync. It then calls snd_pcm_period_elapsed if necessary and + * resubmits itself. + */ +void feedback_urb_complete(struct urb *urb); + +/** + * capture_urb_complete() - Completion handler for capture bulk URBs. + * @urb: the completed URB + * + * This function runs in interrupt context. It copies the received raw data + * into an intermediate ring buffer and then schedules the workqueue to process + * it. It then resubmits the URB to receive more data. + */ +void capture_urb_complete(struct urb *urb); + +/** + * tascam_stop_pcm_work_handler() - Work handler to stop PCM streams. + * @work: Pointer to the work_struct. + * + * This function is scheduled to stop PCM streams (playback and capture) + * from a workqueue context, avoiding blocking operations in interrupt context. + */ +void tascam_stop_pcm_work_handler(struct work_struct *work); + +/** + * tascam_init_pcm() - Initializes the ALSA PCM device. + * @pcm: Pointer to the ALSA PCM device to initialize. + * + * This function sets up the PCM operations, adds ALSA controls for routing + * and sample rate, and preallocates pages for the PCM buffer. + * + * Return: 0 on success, or a negative error code on failure. + */ +int tascam_init_pcm(struct snd_pcm *pcm); + +/** + * us144mkii_configure_device_for_rate() - Set sample rate via USB control msgs + * @tascam: the tascam_card instance + * @rate: the target sample rate (e.g., 44100, 96000) + * + * This function sends a sequence of vendor-specific and UAC control messages + * to configure the device hardware for the specified sample rate. + * + * Return: 0 on success, or a negative error code on failure. + */ +int us144mkii_configure_device_for_rate(struct tascam_card *tascam, int rate); + +/** + * process_playback_routing_us144mkii() - Apply playback routing matrix + * @tascam: The driver instance. + * @src_buffer: Buffer containing 4 channels of S24_3LE audio from ALSA. + * @dst_buffer: Buffer to be filled for the USB device. + * @frames: Number of frames to process. + */ +void process_playback_routing_us144mkii(struct tascam_card *tascam, + const u8 *src_buffer, u8 *dst_buffer, + size_t frames); + +/** + * process_capture_routing_us144mkii() - Apply capture routing matrix + * @tascam: The driver instance. + * @decoded_block: Buffer containing 4 channels of S32LE decoded audio. + * @routed_block: Buffer to be filled for ALSA. + */ +void process_capture_routing_us144mkii(struct tascam_card *tascam, + const s32 *decoded_block, + s32 *routed_block); + +/** + * tascam_pcm_hw_params() - Configures hardware parameters for PCM streams. + * @substream: The ALSA PCM substream. + * @params: The hardware parameters to apply. + * + * This function allocates pages for the PCM buffer and, for playback streams, + * selects the appropriate feedback patterns based on the requested sample rate. + * It also configures the device hardware for the selected sample rate if it + * has changed. + * + * Return: 0 on success, or a negative error code on failure. + */ +int tascam_pcm_hw_params(struct snd_pcm_substream *substream, + struct snd_pcm_hw_params *params); + +/** + * tascam_pcm_hw_free() - Frees hardware parameters for PCM streams. + * @substream: The ALSA PCM substream. + * + * This function is a stub for freeing hardware-related resources. + * + * Return: 0 on success. + */ +int tascam_pcm_hw_free(struct snd_pcm_substream *substream); + +/** + * tascam_pcm_trigger() - Triggers the start or stop of PCM streams. + * @substream: The ALSA PCM substream. + * @cmd: The trigger command (e.g., SNDRV_PCM_TRIGGER_START). + * + * This function handles starting and stopping of playback and capture streams + * by submitting or killing the associated URBs. + * + * Return: 0 on success, or a negative error code on failure. + */ +int tascam_pcm_trigger(struct snd_pcm_substream *substream, int cmd); + +/** + * tascam_capture_work_handler() - Deferred work for processing capture data. + * @work: the work_struct instance + * + * This function runs in a kernel thread context, not an IRQ context. It reads + * raw data from the capture ring buffer, decodes it, applies routing, and + * copies the final audio data into the ALSA capture ring buffer. This offloads + * the CPU-intensive decoding from the time-sensitive URB completion handlers. + */ +void tascam_capture_work_handler(struct work_struct *work); + +#endif /* __US144MKII_PCM_H */ |