[ALSA] Control API - more robust TLV implementation

- added callback option
- added READ/WRITE/COMMAND flags to access member
- added WRITE/COMMAND ioctls
- added SNDRV_CTL_EVENT_MASK_TLV for TLV change notifications
- added TLV support to ELEM_ADD ioctl

Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 109 insertions, 30 deletions

diff --git a/sound/core/control.c b/sound/core/control.c
index f0c7272a2d48..31ad58154c06 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -236,12 +236,16 @@ struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
         kctl.id.index = ncontrol->index;
         kctl.count = ncontrol->count ? ncontrol->count : 1;
         access = ncontrol->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
-                 (ncontrol->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|SNDRV_CTL_ELEM_ACCESS_INACTIVE|
-                                      SNDRV_CTL_ELEM_ACCESS_DINDIRECT|SNDRV_CTL_ELEM_ACCESS_INDIRECT));
+                 (ncontrol->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
+                                      SNDRV_CTL_ELEM_ACCESS_INACTIVE|
+                                      SNDRV_CTL_ELEM_ACCESS_DINDIRECT|
+                                      SNDRV_CTL_ELEM_ACCESS_INDIRECT|
+                                      SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE|
+                                      SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK));
         kctl.info = ncontrol->info;
         kctl.get = ncontrol->get;
         kctl.put = ncontrol->put;
-        kctl.tlv = ncontrol->tlv;
+        kctl.tlv.p = ncontrol->tlv.p;
         kctl.private_value = ncontrol->private_value;
         kctl.private_data = private_data;
         return snd_ctl_new(&kctl, access);
@@ -883,6 +887,8 @@ struct user_element {
         struct snd_ctl_elem_info info;
         void *elem_data;                /* element data */
         unsigned long elem_data_size;   /* size of element data in bytes */
+        void *tlv_data;                 /* TLV data */
+        unsigned long tlv_data_size;    /* TLV data size */
         void *priv_data;                /* private data (like strings for enumerated type) */
         unsigned long priv_data_size;   /* size of private data in bytes */
 };
@@ -917,9 +923,46 @@ static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
         return change;
 }
 
+static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kcontrol,
+                                 int op_flag,
+                                 unsigned int size,
+                                 unsigned int __user *tlv)
+{
+        struct user_element *ue = kcontrol->private_data;
+        int change = 0;
+        void *new_data;
+
+        if (op_flag > 0) {
+                if (size > 1024 * 128)  /* sane value */
+                        return -EINVAL;
+                new_data = kmalloc(size, GFP_KERNEL);
+                if (new_data == NULL)
+                        return -ENOMEM;
+                if (copy_from_user(new_data, tlv, size)) {
+                        kfree(new_data);
+                        return -EFAULT;
+                }
+                change = ue->tlv_data_size != size;
+                if (!change)
+                        change = memcmp(ue->tlv_data, new_data, size);
+                kfree(ue->tlv_data);
+                ue->tlv_data = new_data;
+                ue->tlv_data_size = size;
+        } else {
+                if (size < ue->tlv_data_size)
+                        return -ENOSPC;
+                if (copy_to_user(tlv, ue->tlv_data, ue->tlv_data_size))
+                        return -EFAULT;
+        }
+        return change;
+}
+
 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
 {
-        kfree(kcontrol->private_data);
+        struct user_element *ue = kcontrol->private_data;
+        if (ue->tlv_data)
+                kfree(ue->tlv_data);
+        kfree(ue);
 }
 
 static int snd_ctl_elem_add(struct snd_ctl_file *file,
@@ -938,7 +981,8 @@ static int snd_ctl_elem_add(struct snd_ctl_file *file,
                 return -EINVAL;
         access = info->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
                 (info->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
-                                 SNDRV_CTL_ELEM_ACCESS_INACTIVE));
+                                 SNDRV_CTL_ELEM_ACCESS_INACTIVE|
+                                 SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE));
         info->id.numid = 0;
         memset(&kctl, 0, sizeof(kctl));
         down_write(&card->controls_rwsem);
@@ -964,6 +1008,10 @@ static int snd_ctl_elem_add(struct snd_ctl_file *file,
                 kctl.get = snd_ctl_elem_user_get;
         if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
                 kctl.put = snd_ctl_elem_user_put;
+        if (access & SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE) {
+                kctl.tlv.c = snd_ctl_elem_user_tlv;
+                access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
+        }
         switch (info->type) {
         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
                 private_size = sizeof(char);
@@ -1068,38 +1116,65 @@ static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
         return 0;
 }
 
-static int snd_ctl_tlv_read(struct snd_card *card,
-                            struct snd_ctl_tlv __user *_tlv)
+static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
+                             struct snd_ctl_tlv __user *_tlv,
+                             int op_flag)
 {
+        struct snd_card *card = file->card;
         struct snd_ctl_tlv tlv;
         struct snd_kcontrol *kctl;
+        struct snd_kcontrol_volatile *vd;
         unsigned int len;
         int err = 0;
 
         if (copy_from_user(&tlv, _tlv, sizeof(tlv)))
                 return -EFAULT;
-        if (tlv.length < sizeof(unsigned int) * 3)
-                return -EINVAL;
-        down_read(&card->controls_rwsem);
-        kctl = snd_ctl_find_numid(card, tlv.numid);
-        if (kctl == NULL) {
-                err = -ENOENT;
-                goto __kctl_end;
-        }
-        if (kctl->tlv == NULL) {
-                err = -ENXIO;
-                goto __kctl_end;
-        }
-        len = kctl->tlv[1] + 2 * sizeof(unsigned int);
-        if (tlv.length < len) {
-                err = -ENOMEM;
-                goto __kctl_end;
-        }
-        if (copy_to_user(_tlv->tlv, kctl->tlv, len))
-                err = -EFAULT;
+        if (tlv.length < sizeof(unsigned int) * 3)
+                return -EINVAL;
+        down_read(&card->controls_rwsem);
+        kctl = snd_ctl_find_numid(card, tlv.numid);
+        if (kctl == NULL) {
+                err = -ENOENT;
+                goto __kctl_end;
+        }
+        if (kctl->tlv.p == NULL) {
+                err = -ENXIO;
+                goto __kctl_end;
+        }
+        vd = &kctl->vd[tlv.numid - kctl->id.numid];
+        if ((op_flag == 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ) == 0) ||
+            (op_flag > 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE) == 0) ||
+            (op_flag < 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND) == 0)) {
+                err = -ENXIO;
+                goto __kctl_end;
+        }
+        if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
+                if (file && vd->owner != NULL && vd->owner != file) {
+                        err = -EPERM;
+                        goto __kctl_end;
+                }
+                err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv); 
+                if (err > 0) {
+                        up_read(&card->controls_rwsem);
+                        snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &kctl->id);
+                        return 0;
+                }
+        } else {
+                if (op_flag) {
+                        err = -ENXIO;
+                        goto __kctl_end;
+                }
+                len = kctl->tlv.p[1] + 2 * sizeof(unsigned int);
+                if (tlv.length < len) {
+                        err = -ENOMEM;
+                        goto __kctl_end;
+                }
+                if (copy_to_user(_tlv->tlv, kctl->tlv.p, len))
+                        err = -EFAULT;
+        }
       __kctl_end:
-        up_read(&card->controls_rwsem);
-        return err;
+        up_read(&card->controls_rwsem);
+        return err;
 }
 
 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
@@ -1140,8 +1215,12 @@ static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg
                 return snd_ctl_elem_remove(ctl, argp);
         case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
                 return snd_ctl_subscribe_events(ctl, ip);
-        case SNDRV_CTL_IOCTL_TLV_READ:
-                return snd_ctl_tlv_read(card, argp);
+        case SNDRV_CTL_IOCTL_TLV_READ:
+                return snd_ctl_tlv_ioctl(ctl, argp, 0);
+        case SNDRV_CTL_IOCTL_TLV_WRITE:
+                return snd_ctl_tlv_ioctl(ctl, argp, 1);
+        case SNDRV_CTL_IOCTL_TLV_COMMAND:
+                return snd_ctl_tlv_ioctl(ctl, argp, -1);
         case SNDRV_CTL_IOCTL_POWER:
                 return -ENOPROTOOPT;
         case SNDRV_CTL_IOCTL_POWER_STATE: