From a3a03951fd50e2ccbab415bf74234c00654e5c4b Mon Sep 17 00:00:00 2001 From: Iliyan Malchev Date: Fri, 20 Aug 2010 15:11:48 -0700 Subject: [PATCH] [ARM] tegra: tegra_i2s_audio: allow preloading of the tx fifo with data Add an ioctl to allow the TX fifo to be loaded with data before playback starts. Playback can then be started by calling write() on the FIFO, even with a length of 0. This will cause the pending data to be played out. Signed-off-by: Iliyan Malchev --- arch/arm/mach-tegra/tegra_i2s_audio.c | 20 ++++++++++++++++++++ include/linux/tegra_audio.h | 8 ++++++++ 2 files changed, 28 insertions(+) diff --git a/arch/arm/mach-tegra/tegra_i2s_audio.c b/arch/arm/mach-tegra/tegra_i2s_audio.c index 40653570f87a..47626e103e8d 100644 --- a/arch/arm/mach-tegra/tegra_i2s_audio.c +++ b/arch/arm/mach-tegra/tegra_i2s_audio.c @@ -1262,6 +1262,26 @@ static long tegra_audio_out_ioctl(struct file *file, if (!rc) aos->errors = 0; break; + case TEGRA_AUDIO_OUT_PRELOAD_FIFO: { + struct tegra_audio_out_preload preload; + if (copy_from_user(&preload, (void __user *)arg, + sizeof(preload))) { + rc = -EFAULT; + break; + } + rc = kfifo_from_user(&ads->out.fifo, + (void __user *)preload.data, preload.len, + &preload.len_written); + if (rc < 0) { + pr_err("%s: error copying from user\n", __func__); + break; + } + if (copy_to_user((void __user *)arg, &preload, sizeof(preload))) + rc = -EFAULT; + pr_info("%s: preloaded output fifo with %d bytes\n", __func__, + preload.len_written); + } + break; default: rc = -EINVAL; } diff --git a/include/linux/tegra_audio.h b/include/linux/tegra_audio.h index 48590daa06a5..15139cc31d84 100644 --- a/include/linux/tegra_audio.h +++ b/include/linux/tegra_audio.h @@ -58,5 +58,13 @@ struct tegra_audio_buf_config { #define TEGRA_AUDIO_OUT_GET_ERROR_COUNT _IOR(TEGRA_AUDIO_MAGIC, 9, \ unsigned *) +struct tegra_audio_out_preload { + void *data; + size_t len; + size_t len_written; +}; + +#define TEGRA_AUDIO_OUT_PRELOAD_FIFO _IOWR(TEGRA_AUDIO_MAGIC, 10, \ + struct tegra_audio_out_preload *) #endif/*_CPCAP_AUDIO_H*/ -- 2.34.1