sound/usb/clock.c

   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
  36 static 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
  52 static 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
  68 static 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
  84 static 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
 102 static 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, UAC2_CS_CONTROL_CLOCK_VALID))
 115                 return 1;
 116
 117         err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
 118                               USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
 119                               UAC2_CS_CONTROL_CLOCK_VALID << 8,
 120                               snd_usb_ctrl_intf(chip) | (source_id << 8),
 121                               &data, sizeof(data));
 122
 123         if (err < 0) {
 124                 snd_printk(KERN_WARNING "%s(): cannot get clock validity for id %d\n",
 125                            __func__, source_id);
 126                 return 0;
 127         }
 128
 129         return !!data;
 130 }
 131
 132 static int __uac_clock_find_source(struct snd_usb_audio *chip,
 133                                    int entity_id, unsigned long *visited)
 134 {
 135         struct uac_clock_source_descriptor *source;
 136         struct uac_clock_selector_descriptor *selector;
 137         struct uac_clock_multiplier_descriptor *multiplier;
 138
 139         entity_id &= 0xff;
 140
 141         if (test_and_set_bit(entity_id, visited)) {
 142                 snd_printk(KERN_WARNING
 143                         "%s(): recursive clock topology detected, id %d.\n",
 144                         __func__, entity_id);
 145                 return -EINVAL;
 146         }
 147
 148         /* first, see if the ID we're looking for is a clock source already */
 149         source = snd_usb_find_clock_source(chip->ctrl_intf, entity_id);
 150         if (source)
 151                 return source->bClockID;
 152
 153         selector = snd_usb_find_clock_selector(chip->ctrl_intf, entity_id);
 154         if (selector) {
 155                 int ret;
 156
 157                 /* the entity ID we are looking for is a selector.
 158                  * find out what it currently selects */
 159                 ret = uac_clock_selector_get_val(chip, selector->bClockID);
 160                 if (ret < 0)
 161                         return ret;
 162
 163                 /* Selector values are one-based */
 164
 165                 if (ret > selector->bNrInPins || ret < 1) {
 166                         printk(KERN_ERR
 167                                 "%s(): selector reported illegal value, id %d, ret %d\n",
 168                                 __func__, selector->bClockID, ret);
 169
 170                         return -EINVAL;
 171                 }
 172
 173                 return __uac_clock_find_source(chip, selector->baCSourceID[ret-1],
 174                                                visited);
 175         }
 176
 177         /* FIXME: multipliers only act as pass-thru element for now */
 178         multiplier = snd_usb_find_clock_multiplier(chip->ctrl_intf, entity_id);
 179         if (multiplier)
 180                 return __uac_clock_find_source(chip, multiplier->bCSourceID,
 181                                                 visited);
 182
 183         return -EINVAL;
 184 }
 185
 186 /*
 187  * For all kinds of sample rate settings and other device queries,
 188  * the clock source (end-leaf) must be used. However, clock selectors,
 189  * clock multipliers and sample rate converters may be specified as
 190  * clock source input to terminal. This functions walks the clock path
 191  * to its end and tries to find the source.
 192  *
 193  * The 'visited' bitfield is used internally to detect recursive loops.
 194  *
 195  * Returns the clock source UnitID (>=0) on success, or an error.
 196  */
 197 int snd_usb_clock_find_source(struct snd_usb_audio *chip, int entity_id)
 198 {
 199         DECLARE_BITMAP(visited, 256);
 200         memset(visited, 0, sizeof(visited));
 201         return __uac_clock_find_source(chip, entity_id, visited);
 202 }
 203
 204 static int set_sample_rate_v1(struct snd_usb_audio *chip, int iface,
 205                               struct usb_host_interface *alts,
 206                               struct audioformat *fmt, int rate)
 207 {
 208         struct usb_device *dev = chip->dev;
 209         unsigned int ep;
 210         unsigned char data[3];
 211         int err, crate;
 212
 213         ep = get_endpoint(alts, 0)->bEndpointAddress;
 214
 215         /* if endpoint doesn't have sampling rate control, bail out */
 216         if (!(fmt->attributes & UAC_EP_CS_ATTR_SAMPLE_RATE))
 217                 return 0;
 218
 219         data[0] = rate;
 220         data[1] = rate >> 8;
 221         data[2] = rate >> 16;
 222         if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
 223                                    USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
 224                                    UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep,
 225                                    data, sizeof(data))) < 0) {
 226                 snd_printk(KERN_ERR "%d:%d:%d: cannot set freq %d to ep %#x\n",
 227                            dev->devnum, iface, fmt->altsetting, rate, ep);
 228                 return err;
 229         }
 230
 231         if ((err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC_GET_CUR,
 232                                    USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_IN,
 233                                    UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep,
 234                                    data, sizeof(data))) < 0) {
 235                 snd_printk(KERN_WARNING "%d:%d:%d: cannot get freq at ep %#x\n",
 236                            dev->devnum, iface, fmt->altsetting, ep);
 237                 return 0; /* some devices don't support reading */
 238         }
 239
 240         crate = data[0] | (data[1] << 8) | (data[2] << 16);
 241         if (crate != rate) {
 242                 snd_printd(KERN_WARNING "current rate %d is different from the runtime rate %d\n", crate, rate);
 243                 // runtime->rate = crate;
 244         }
 245
 246         return 0;
 247 }
 248
 249 static int set_sample_rate_v2(struct snd_usb_audio *chip, int iface,
 250                               struct usb_host_interface *alts,
 251                               struct audioformat *fmt, int rate)
 252 {
 253         struct usb_device *dev = chip->dev;
 254         unsigned char data[4];
 255         int err, crate;
 256         int clock = snd_usb_clock_find_source(chip, fmt->clock);
 257
 258         if (clock < 0)
 259                 return clock;
 260
 261         if (!uac_clock_source_is_valid(chip, clock)) {
 262                 /* TODO: should we try to find valid clock setups by ourself? */
 263                 snd_printk(KERN_ERR "%d:%d:%d: clock source %d is not valid, cannot use\n",
 264                            dev->devnum, iface, fmt->altsetting, clock);
 265                 return -ENXIO;
 266         }
 267
 268         data[0] = rate;
 269         data[1] = rate >> 8;
 270         data[2] = rate >> 16;
 271         data[3] = rate >> 24;
 272         if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
 273                                    USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
 274                                    UAC2_CS_CONTROL_SAM_FREQ << 8,
 275                                    snd_usb_ctrl_intf(chip) | (clock << 8),
 276                                    data, sizeof(data))) < 0) {
 277                 snd_printk(KERN_ERR "%d:%d:%d: cannot set freq %d (v2)\n",
 278                            dev->devnum, iface, fmt->altsetting, rate);
 279                 return err;
 280         }
 281
 282         if ((err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
 283                                    USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
 284                                    UAC2_CS_CONTROL_SAM_FREQ << 8,
 285                                    snd_usb_ctrl_intf(chip) | (clock << 8),
 286                                    data, sizeof(data))) < 0) {
 287                 snd_printk(KERN_WARNING "%d:%d:%d: cannot get freq (v2)\n",
 288                            dev->devnum, iface, fmt->altsetting);
 289                 return err;
 290         }
 291
 292         crate = data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
 293         if (crate != rate)
 294                 snd_printd(KERN_WARNING "current rate %d is different from the runtime rate %d\n", crate, rate);
 295
 296         return 0;
 297 }
 298
 299 int snd_usb_init_sample_rate(struct snd_usb_audio *chip, int iface,
 300                              struct usb_host_interface *alts,
 301                              struct audioformat *fmt, int rate)
 302 {
 303         struct usb_interface_descriptor *altsd = get_iface_desc(alts);
 304
 305         switch (altsd->bInterfaceProtocol) {
 306         case UAC_VERSION_1:
 307         default:
 308                 return set_sample_rate_v1(chip, iface, alts, fmt, rate);
 309
 310         case UAC_VERSION_2:
 311                 return set_sample_rate_v2(chip, iface, alts, fmt, rate);
 312         }
 313 }
 314