linux/sound/usb/clock.c
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   1/*
   2 *   Clock domain and sample rate management functions
   3 *
   4 *   This program is free software; you can redistribute it and/or modify
   5 *   it under the terms of the GNU General Public License as published by
   6 *   the Free Software Foundation; either version 2 of the License, or
   7 *   (at your option) any later version.
   8 *
   9 *   This program is distributed in the hope that it will be useful,
  10 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 *   GNU General Public License for more details.
  13 *
  14 *   You should have received a copy of the GNU General Public License
  15 *   along with this program; if not, write to the Free Software
  16 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  17 *
  18 */
  19
  20#include <linux/bitops.h>
  21#include <linux/init.h>
  22#include <linux/string.h>
  23#include <linux/usb.h>
  24#include <linux/usb/audio.h>
  25#include <linux/usb/audio-v2.h>
  26
  27#include <sound/core.h>
  28#include <sound/info.h>
  29#include <sound/pcm.h>
  30
  31#include "usbaudio.h"
  32#include "card.h"
  33#include "helper.h"
  34#include "clock.h"
  35
  36static struct uac_clock_source_descriptor *
  37        snd_usb_find_clock_source(struct usb_host_interface *ctrl_iface,
  38                                  int clock_id)
  39{
  40        struct uac_clock_source_descriptor *cs = NULL;
  41
  42        while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
  43                                             ctrl_iface->extralen,
  44                                             cs, UAC2_CLOCK_SOURCE))) {
  45                if (cs->bClockID == clock_id)
  46                        return cs;
  47        }
  48
  49        return NULL;
  50}
  51
  52static struct uac_clock_selector_descriptor *
  53        snd_usb_find_clock_selector(struct usb_host_interface *ctrl_iface,
  54                                    int clock_id)
  55{
  56        struct uac_clock_selector_descriptor *cs = NULL;
  57
  58        while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
  59                                             ctrl_iface->extralen,
  60                                             cs, UAC2_CLOCK_SELECTOR))) {
  61                if (cs->bClockID == clock_id)
  62                        return cs;
  63        }
  64
  65        return NULL;
  66}
  67
  68static struct uac_clock_multiplier_descriptor *
  69        snd_usb_find_clock_multiplier(struct usb_host_interface *ctrl_iface,
  70                                      int clock_id)
  71{
  72        struct uac_clock_multiplier_descriptor *cs = NULL;
  73
  74        while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
  75                                             ctrl_iface->extralen,
  76                                             cs, UAC2_CLOCK_MULTIPLIER))) {
  77                if (cs->bClockID == clock_id)
  78                        return cs;
  79        }
  80
  81        return NULL;
  82}
  83
  84static int uac_clock_selector_get_val(struct snd_usb_audio *chip, int selector_id)
  85{
  86        unsigned char buf;
  87        int ret;
  88
  89        ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
  90                              UAC2_CS_CUR,
  91                              USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
  92                              UAC2_CX_CLOCK_SELECTOR << 8,
  93                              snd_usb_ctrl_intf(chip) | (selector_id << 8),
  94                              &buf, sizeof(buf));
  95
  96        if (ret < 0)
  97                return ret;
  98
  99        return buf;
 100}
 101
 102static bool uac_clock_source_is_valid(struct snd_usb_audio *chip, int source_id)
 103{
 104        int err;
 105        unsigned char data;
 106        struct usb_device *dev = chip->dev;
 107        struct uac_clock_source_descriptor *cs_desc =
 108                snd_usb_find_clock_source(chip->ctrl_intf, source_id);
 109
 110        if (!cs_desc)
 111                return 0;
 112
 113        /* If a clock source can't tell us whether it's valid, we assume it is */
 114        if (!uac2_control_is_readable(cs_desc->bmControls,
 115                                      UAC2_CS_CONTROL_CLOCK_VALID - 1))
 116                return 1;
 117
 118        err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
 119                              USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
 120                              UAC2_CS_CONTROL_CLOCK_VALID << 8,
 121                              snd_usb_ctrl_intf(chip) | (source_id << 8),
 122                              &data, sizeof(data));
 123
 124        if (err < 0) {
 125                snd_printk(KERN_WARNING "%s(): cannot get clock validity for id %d\n",
 126                           __func__, source_id);
 127                return 0;
 128        }
 129
 130        return !!data;
 131}
 132
 133static int __uac_clock_find_source(struct snd_usb_audio *chip,
 134                                   int entity_id, unsigned long *visited)
 135{
 136        struct uac_clock_source_descriptor *source;
 137        struct uac_clock_selector_descriptor *selector;
 138        struct uac_clock_multiplier_descriptor *multiplier;
 139
 140        entity_id &= 0xff;
 141
 142        if (test_and_set_bit(entity_id, visited)) {
 143                snd_printk(KERN_WARNING
 144                        "%s(): recursive clock topology detected, id %d.\n",
 145                        __func__, entity_id);
 146                return -EINVAL;
 147        }
 148
 149        /* first, see if the ID we're looking for is a clock source already */
 150        source = snd_usb_find_clock_source(chip->ctrl_intf, entity_id);
 151        if (source)
 152                return source->bClockID;
 153
 154        selector = snd_usb_find_clock_selector(chip->ctrl_intf, entity_id);
 155        if (selector) {
 156                int ret;
 157
 158                /* the entity ID we are looking for is a selector.
 159                 * find out what it currently selects */
 160                ret = uac_clock_selector_get_val(chip, selector->bClockID);
 161                if (ret < 0)
 162                        return ret;
 163
 164                /* Selector values are one-based */
 165
 166                if (ret > selector->bNrInPins || ret < 1) {
 167                        printk(KERN_ERR
 168                                "%s(): selector reported illegal value, id %d, ret %d\n",
 169                                __func__, selector->bClockID, ret);
 170
 171                        return -EINVAL;
 172                }
 173
 174                return __uac_clock_find_source(chip, selector->baCSourceID[ret-1],
 175                                               visited);
 176        }
 177
 178        /* FIXME: multipliers only act as pass-thru element for now */
 179        multiplier = snd_usb_find_clock_multiplier(chip->ctrl_intf, entity_id);
 180        if (multiplier)
 181                return __uac_clock_find_source(chip, multiplier->bCSourceID,
 182                                                visited);
 183
 184        return -EINVAL;
 185}
 186
 187/*
 188 * For all kinds of sample rate settings and other device queries,
 189 * the clock source (end-leaf) must be used. However, clock selectors,
 190 * clock multipliers and sample rate converters may be specified as
 191 * clock source input to terminal. This functions walks the clock path
 192 * to its end and tries to find the source.
 193 *
 194 * The 'visited' bitfield is used internally to detect recursive loops.
 195 *
 196 * Returns the clock source UnitID (>=0) on success, or an error.
 197 */
 198int snd_usb_clock_find_source(struct snd_usb_audio *chip, int entity_id)
 199{
 200        DECLARE_BITMAP(visited, 256);
 201        memset(visited, 0, sizeof(visited));
 202        return __uac_clock_find_source(chip, entity_id, visited);
 203}
 204
 205static int set_sample_rate_v1(struct snd_usb_audio *chip, int iface,
 206                              struct usb_host_interface *alts,
 207                              struct audioformat *fmt, int rate)
 208{
 209        struct usb_device *dev = chip->dev;
 210        unsigned int ep;
 211        unsigned char data[3];
 212        int err, crate;
 213
 214        ep = get_endpoint(alts, 0)->bEndpointAddress;
 215
 216        /* if endpoint doesn't have sampling rate control, bail out */
 217        if (!(fmt->attributes & UAC_EP_CS_ATTR_SAMPLE_RATE))
 218                return 0;
 219
 220        data[0] = rate;
 221        data[1] = rate >> 8;
 222        data[2] = rate >> 16;
 223        if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
 224                                   USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
 225                                   UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep,
 226                                   data, sizeof(data))) < 0) {
 227                snd_printk(KERN_ERR "%d:%d:%d: cannot set freq %d to ep %#x\n",
 228                           dev->devnum, iface, fmt->altsetting, rate, ep);
 229                return err;
 230        }
 231
 232        if ((err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC_GET_CUR,
 233                                   USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_IN,
 234                                   UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep,
 235                                   data, sizeof(data))) < 0) {
 236                snd_printk(KERN_WARNING "%d:%d:%d: cannot get freq at ep %#x\n",
 237                           dev->devnum, iface, fmt->altsetting, ep);
 238                return 0; /* some devices don't support reading */
 239        }
 240
 241        crate = data[0] | (data[1] << 8) | (data[2] << 16);
 242        if (crate != rate) {
 243                snd_printd(KERN_WARNING "current rate %d is different from the runtime rate %d\n", crate, rate);
 244                // runtime->rate = crate;
 245        }
 246
 247        return 0;
 248}
 249
 250static int set_sample_rate_v2(struct snd_usb_audio *chip, int iface,
 251                              struct usb_host_interface *alts,
 252                              struct audioformat *fmt, int rate)
 253{
 254        struct usb_device *dev = chip->dev;
 255        unsigned char data[4];
 256        int err, crate;
 257        int clock = snd_usb_clock_find_source(chip, fmt->clock);
 258
 259        if (clock < 0)
 260                return clock;
 261
 262        if (!uac_clock_source_is_valid(chip, clock)) {
 263                /* TODO: should we try to find valid clock setups by ourself? */
 264                snd_printk(KERN_ERR "%d:%d:%d: clock source %d is not valid, cannot use\n",
 265                           dev->devnum, iface, fmt->altsetting, clock);
 266                return -ENXIO;
 267        }
 268
 269        data[0] = rate;
 270        data[1] = rate >> 8;
 271        data[2] = rate >> 16;
 272        data[3] = rate >> 24;
 273        if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
 274                                   USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
 275                                   UAC2_CS_CONTROL_SAM_FREQ << 8,
 276                                   snd_usb_ctrl_intf(chip) | (clock << 8),
 277                                   data, sizeof(data))) < 0) {
 278                snd_printk(KERN_ERR "%d:%d:%d: cannot set freq %d (v2)\n",
 279                           dev->devnum, iface, fmt->altsetting, rate);
 280                return err;
 281        }
 282
 283        if ((err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
 284                                   USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
 285                                   UAC2_CS_CONTROL_SAM_FREQ << 8,
 286                                   snd_usb_ctrl_intf(chip) | (clock << 8),
 287                                   data, sizeof(data))) < 0) {
 288                snd_printk(KERN_WARNING "%d:%d:%d: cannot get freq (v2)\n",
 289                           dev->devnum, iface, fmt->altsetting);
 290                return err;
 291        }
 292
 293        crate = data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
 294        if (crate != rate)
 295                snd_printd(KERN_WARNING "current rate %d is different from the runtime rate %d\n", crate, rate);
 296
 297        return 0;
 298}
 299
 300int snd_usb_init_sample_rate(struct snd_usb_audio *chip, int iface,
 301                             struct usb_host_interface *alts,
 302                             struct audioformat *fmt, int rate)
 303{
 304        struct usb_interface_descriptor *altsd = get_iface_desc(alts);
 305
 306        switch (altsd->bInterfaceProtocol) {
 307        case UAC_VERSION_1:
 308        default:
 309                return set_sample_rate_v1(chip, iface, alts, fmt, rate);
 310
 311        case UAC_VERSION_2:
 312                return set_sample_rate_v2(chip, iface, alts, fmt, rate);
 313        }
 314}
 315
 316
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