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,
 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
 133 static 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  */
 198 int 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
 205 static 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
 250 static 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
 300 int 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