Commit 393aa9c1 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: Mandate to pass a device pointer at card creation time 



This is a part of preliminary works for modernizing the ALSA device
structure.  So far, we set card->dev at later point after the object
creation.  Because of this, the core layer doesn't always know which
device is being handled before it's actually registered, and it makes
impossible to show the device in error messages, for example.  The
first goal is to achieve a proper struct device initialization at the
very beginning of probing.

As a first step, this patch introduces snd_card_new() function (yes
there was the same named function in the very past), in order to
receive the parent device pointer from the very beginning.
snd_card_create() is marked as deprecated.

At this point, there is no functional change other than that.  The
actual change of the device creation scheme will follow later.

Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 80d7d771

Documentation/DocBook/writing-an-alsa-driver.tmpl

+27 −45
Original line number Diff line number Diff line
@@ -468,8 +468,6 @@ 
                  return err;

          }



          snd_card_set_dev(card, &pci->dev);



          *rchip = chip;

          return 0;

  }
@@ -492,7 +490,8 @@ 
          }



          /* (2) */

          err = snd_card_create(index[dev], id[dev], THIS_MODULE, 0, &card);

          err = snd_card_new(&pci->dev, index[dev], id[dev], THIS_MODULE,

                             0, &card);

          if (err < 0)

                  return err;
@@ -591,7 +590,8 @@ 
  struct snd_card *card;

  int err;

  ....

  err = snd_card_create(index[dev], id[dev], THIS_MODULE, 0, &card);

  err = snd_card_new(&pci->dev, index[dev], id[dev], THIS_MODULE,

                     0, &card);

]]>

            </programlisting>

          </informalexample>
@@ -809,28 +809,34 @@ 


      <para>

        As mentioned above, to create a card instance, call

      <function>snd_card_create()</function>.

      <function>snd_card_new()</function>.



        <informalexample>

          <programlisting>

<![CDATA[

  struct snd_card *card;

  int err;

  err = snd_card_create(index, id, module, extra_size, &card);

  err = snd_card_new(&pci->dev, index, id, module, extra_size, &card);

]]>

          </programlisting>

        </informalexample>

      </para>



      <para>

        The function takes five arguments, the card-index number, the

        id string, the module pointer (usually

        The function takes six arguments: the parent device pointer,

        the card-index number, the id string, the module pointer (usually

        <constant>THIS_MODULE</constant>),

        the size of extra-data space, and the pointer to return the

        card instance.  The extra_size argument is used to

        allocate card-&gt;private_data for the

        chip-specific data.  Note that these data

        are allocated by <function>snd_card_create()</function>.

        are allocated by <function>snd_card_new()</function>.

      </para>



      <para>

	The first argument, the pointer of struct

	<structname>device</structname>, specifies the parent device.

	For PCI devices, typically &amp;pci-&gt; is passed there.

      </para>

    </section>
@@ -916,15 +922,15 @@ 
      </para>



      <section id="card-management-chip-specific-snd-card-new">

        <title>1. Allocating via <function>snd_card_create()</function>.</title>

        <title>1. Allocating via <function>snd_card_new()</function>.</title>

        <para>

          As mentioned above, you can pass the extra-data-length

	  to the 4th argument of <function>snd_card_create()</function>, i.e.

	  to the 5th argument of <function>snd_card_new()</function>, i.e.



          <informalexample>

            <programlisting>

<![CDATA[

  err = snd_card_create(index[dev], id[dev], THIS_MODULE,

  err = snd_card_new(&pci->dev, index[dev], id[dev], THIS_MODULE,

                     sizeof(struct mychip), &card);

]]>

            </programlisting>
@@ -954,7 +960,7 @@ 


        <para>

          After allocating a card instance via

          <function>snd_card_create()</function> (with

          <function>snd_card_new()</function> (with

          <constant>0</constant> on the 4th arg), call

          <function>kzalloc()</function>.
@@ -963,7 +969,8 @@ 
<![CDATA[

  struct snd_card *card;

  struct mychip *chip;

  err = snd_card_create(index[dev], id[dev], THIS_MODULE, 0, &card);

  err = snd_card_new(&pci->dev, index[dev], id[dev], THIS_MODULE,

                     0, &card);

  .....

  chip = kzalloc(sizeof(*chip), GFP_KERNEL);

]]>
@@ -1170,8 +1177,6 @@ 
                  return err;

          }



          snd_card_set_dev(card, &pci->dev);



          *rchip = chip;

          return 0;

  }
@@ -1526,30 +1531,6 @@ 


    </section>



    <section id="pci-resource-device-struct">

      <title>Registration of Device Struct</title>

      <para>

	At some point, typically after calling <function>snd_device_new()</function>,

	you need to register the struct <structname>device</structname> of the chip

	you're handling for udev and co.  ALSA provides a macro for compatibility with

	older kernels.  Simply call like the following:

        <informalexample>

          <programlisting>

<![CDATA[

  snd_card_set_dev(card, &pci->dev);

]]>

          </programlisting>

        </informalexample>

	so that it stores the PCI's device pointer to the card.  This will be

	referred by ALSA core functions later when the devices are registered.

      </para>

      <para>

	In the case of non-PCI, pass the proper device struct pointer of the BUS

	instead.  (In the case of legacy ISA without PnP, you don't have to do

	anything.)

      </para>

    </section>



    <section id="pci-resource-entries">

      <title>PCI Entries</title>

      <para>
@@ -5740,7 +5721,8 @@ struct _snd_pcm_runtime { 
          struct mychip *chip;

          int err;

          ....

          err = snd_card_create(index[dev], id[dev], THIS_MODULE, 0, &card);

          err = snd_card_new(&pci->dev, index[dev], id[dev], THIS_MODULE,

                             0, &card);

          ....

          chip = kzalloc(sizeof(*chip), GFP_KERNEL);

          ....
@@ -5752,7 +5734,7 @@ struct _snd_pcm_runtime { 
      </informalexample>



	When you created the chip data with

	<function>snd_card_create()</function>, it's anyway accessible

	<function>snd_card_new()</function>, it's anyway accessible

	via <structfield>private_data</structfield> field.



      <informalexample>
@@ -5766,7 +5748,7 @@ struct _snd_pcm_runtime { 
          struct mychip *chip;

          int err;

          ....

          err = snd_card_create(index[dev], id[dev], THIS_MODULE,

          err = snd_card_new(&pci->dev, index[dev], id[dev], THIS_MODULE,

                             sizeof(struct mychip), &card);

          ....

          chip = card->private_data;

include/sound/core.h

+10 −3
Original line number Diff line number Diff line
@@ -283,10 +283,17 @@ int snd_card_locked(int card); 
extern int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int cmd);

#endif



int snd_card_create(int idx, const char *id,

int snd_card_new(struct device *parent, int idx, const char *xid,

		 struct module *module, int extra_size,

		 struct snd_card **card_ret);



static inline int __deprecated

snd_card_create(int idx, const char *id, struct module *module, int extra_size,

		struct snd_card **ret)

{

	return snd_card_new(NULL, idx, id, module, extra_size, ret);

}



int snd_card_disconnect(struct snd_card *card);

int snd_card_free(struct snd_card *card);

int snd_card_free_when_closed(struct snd_card *card);

sound/core/init.c

+5 −3
Original line number Diff line number Diff line
@@ -157,7 +157,8 @@ static int get_slot_from_bitmask(int mask, int (*check)(struct module *, int), 
}



/**

 *  snd_card_create - create and initialize a soundcard structure

 *  snd_card_new - create and initialize a soundcard structure

 *  @parent: the parent device object

 *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]

 *  @xid: card identification (ASCII string)

 *  @module: top level module for locking
@@ -172,7 +173,7 @@ static int get_slot_from_bitmask(int mask, int (*check)(struct module *, int), 
 *

 *  Return: Zero if successful or a negative error code.

 */

int snd_card_create(int idx, const char *xid,

int snd_card_new(struct device *parent, int idx, const char *xid,

		    struct module *module, int extra_size,

		    struct snd_card **card_ret)

{
@@ -213,6 +214,7 @@ int snd_card_create(int idx, const char *xid, 
	if (idx >= snd_ecards_limit)

		snd_ecards_limit = idx + 1; /* increase the limit */

	mutex_unlock(&snd_card_mutex);

	card->dev = parent;

	card->number = idx;

	card->module = module;

	INIT_LIST_HEAD(&card->devices);
@@ -251,7 +253,7 @@ int snd_card_create(int idx, const char *xid, 
	kfree(card);

  	return err;

}

EXPORT_SYMBOL(snd_card_create);

EXPORT_SYMBOL(snd_card_new);



/* return non-zero if a card is already locked */

int snd_card_locked(int card)

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