From: satendra singh thakur satendra.t@samsung.com
-Added 2 ioctls in alsa driver's control interface -Added an ioctl to read values of multiple elements at once -Added an ioctl to write values of multiple elements at once -In the absence of above ioctls user needs to call N ioctls to read/write value of N elements which requires N context switches -Proposed ioctls will allow accessing N elements' values in a single context switch -Above mentioned ioctl will be useful for alsa utils such as amixer which reads all controls of given sound card
Signed-off-by: Satendra Singh Thakur satendra.t@samsung.com --- include/uapi/sound/asound.h | 8 +++++ sound/core/control.c | 69 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 77 insertions(+)
diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h index be353a7..a0dcee7 100644 --- a/include/uapi/sound/asound.h +++ b/include/uapi/sound/asound.h @@ -948,6 +948,11 @@ struct snd_ctl_tlv { unsigned int length; /* in bytes aligned to 4 */ unsigned int tlv[0]; /* first TLV */ }; +/*Struct to read/write multiple element values */ +struct snd_ctl_elem_values { + unsigned int num_vals;/* Number of values*/ + struct snd_ctl_elem_value *pvals;/* Pointer to the array of values */ +};
#define SNDRV_CTL_IOCTL_PVERSION _IOR('U', 0x00, int) #define SNDRV_CTL_IOCTL_CARD_INFO _IOR('U', 0x01, struct snd_ctl_card_info) @@ -974,6 +979,9 @@ struct snd_ctl_tlv { #define SNDRV_CTL_IOCTL_RAWMIDI_PREFER_SUBDEVICE _IOW('U', 0x42, int) #define SNDRV_CTL_IOCTL_POWER _IOWR('U', 0xd0, int) #define SNDRV_CTL_IOCTL_POWER_STATE _IOR('U', 0xd1, int) +/*Multipe controls' values read and write*/ +#define SNDRV_CTL_IOCTL_ELEMS_READ _IOWR('U', 0xe0, struct snd_ctl_elem_values) +#define SNDRV_CTL_IOCTL_ELEMS_WRITE _IOWR('U', 0xe1, struct snd_ctl_elem_values)
/* * Read interface. diff --git a/sound/core/control.c b/sound/core/control.c index fb096cb..d60dc98 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -942,6 +942,7 @@ static int snd_ctl_elem_read_user(struct snd_card *card, return result; }
+ static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file, struct snd_ctl_elem_value *control) { @@ -1000,6 +1001,70 @@ static int snd_ctl_elem_write_user(struct snd_ctl_file *file, return result; }
+/** + * snd_ctl_elems_rw_user - Read/Write values of more than one element, + * one by one + * @card: the card to which element belongs to + * @pucontrols: user-space pointer to struct snd_ctl_elem_values + * @write_flag: this flag distinguises write or read type request + * + * This function reads/writes the value of controls with the given IDs + * of the same card + * Return: On full/partial success, It returns number of successful + * controls read/written. + * On failure, it returns appropriate error + */ +static int snd_ctl_elems_rw_user(struct snd_ctl_file *file, + struct snd_ctl_elem_values __user *pucontrols, + bool write_flag) +{ + struct snd_ctl_elem_values controls; + struct snd_ctl_elem_value control; + struct snd_ctl_elem_value __user *puvals; + struct snd_card *card = file->card; + int result; + int vals; + int controls_count = 0; + + if (copy_from_user(&controls, pucontrols, sizeof(controls))) + return -EFAULT; + if (!controls.num_vals || controls.num_vals > card->controls_count) + return -EINVAL; + /*assign user-space pointer**/ + puvals = (struct snd_ctl_elem_value __user *) controls.pvals; + for (vals = 0; vals < controls.num_vals; vals++) { + if (copy_from_user(&control, puvals + vals, sizeof(control))) + return -EFAULT; + snd_power_lock(card); + result = snd_power_wait(card, SNDRV_CTL_POWER_D0); + if (result >= 0) { + if (write_flag == true) + result = snd_ctl_elem_write(card, file, + &control); + else + result = snd_ctl_elem_read(card, &control); + } + snd_power_unlock(card); + if (result < 0) { + /**If control failed to set/get + * inform user by sending back -1 in reserved field + * so that one can try again for failed elements + */ + control.reserved[0] = (unsigned char) -1; + pr_err("ALSA: control: snd_ctl_elem_write/read failed\ + for control name = %s\n", control.id.name); + } else { + controls_count++; + } + if (copy_to_user(puvals + vals, &control, sizeof(control))) + return -EFAULT; + } + pr_debug("ALSA: control: Num values successfully read/written %u\n",\ + controls_count); + /**Return successful control count to user**/ + return controls_count; +} + static int snd_ctl_elem_lock(struct snd_ctl_file *file, struct snd_ctl_elem_id __user *_id) { @@ -1515,8 +1580,12 @@ static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg return snd_ctl_elem_info_user(ctl, argp); case SNDRV_CTL_IOCTL_ELEM_READ: return snd_ctl_elem_read_user(card, argp); + case SNDRV_CTL_IOCTL_ELEMS_READ: + return snd_ctl_elems_rw_user(ctl, argp, false); case SNDRV_CTL_IOCTL_ELEM_WRITE: return snd_ctl_elem_write_user(ctl, argp); + case SNDRV_CTL_IOCTL_ELEMS_WRITE: + return snd_ctl_elems_rw_user(ctl, argp, true); case SNDRV_CTL_IOCTL_ELEM_LOCK: return snd_ctl_elem_lock(ctl, argp); case SNDRV_CTL_IOCTL_ELEM_UNLOCK: