updated CDROMREADAUDIO DMA patch

@@ -1911,6 +1911,107 @@ static int cdrom_do_cmd(struct cdrom_dev
 	return ret;
 }
 
+/*
+ * CDROM audio read, with DMA support.  Added in 2.4.18-pre4, akpm.
+ *
+ * Initially, we try to perform multiframe bus-mastering.  If the IDE
+ * layer experiences a DMA error, we fall back to single-frame DMA.
+ * If the IDE layer again detects a DMA error, we fall back to multiframe
+ * PIO.
+ *
+ * We do not want to disable drive-level DMA at any stage, because
+ * some devices can perform non-packet DMA quite happily, but appear
+ * to not be able to perform packet DMA correctly.
+ *
+ * If the drive is not using_dma, we never attempt packet DMA.
+ */
+static int cdda_read_audio(int cmd,
+			struct cdrom_device_info *cdi,
+			struct cdrom_generic_command *cgc,
+			struct cdrom_read_audio *ra)
+{
+	int lba;
+	unsigned frames_todo;
+	int ret;
+	void *xferbuf = 0;
+	unsigned nr_local_frames;
+	char *useraddr;
+
+	ret = -EINVAL;
+	if (ra->addr_format == CDROM_MSF) {
+		lba = msf_to_lba(ra->addr.msf.minute,
+				 ra->addr.msf.second,
+				 ra->addr.msf.frame);
+	} else if (ra->addr_format == CDROM_LBA) {
+		lba = ra->addr.lba;
+	} else {
+		goto out;
+	}
+
+	if (lba < 0 || ra->nframes <= 0)
+		goto out;
+
+	/*
+	 * We can't sensibly support more that 64k because we later
+	 * use a buffer_head to map the temp buffer.  And b_count is
+	 * unsigned short.
+	 */
+	nr_local_frames = ra->nframes;
+	if (nr_local_frames * CD_FRAMESIZE_RAW > 32768)
+		nr_local_frames = 32768 / CD_FRAMESIZE_RAW;
+
+	if (cdi->dma_mode == CDROM_DMA_SINGLE)
+		nr_local_frames = 1;
+
+	do {
+		xferbuf = kmalloc(CD_FRAMESIZE_RAW * nr_local_frames, GFP_KERNEL);
+	} while (!xferbuf && nr_local_frames--);
+	ret = -ENOMEM;
+	if (!xferbuf)
+		goto out;
+
+	cgc->buffer = xferbuf;
+	cgc->data_direction = CGC_DATA_READ;
+	if (cdi->dma_mode != CDROM_DMA_NONE)
+		cgc->do_dma = 1;
+	frames_todo = ra->nframes;
+	useraddr = ra->buf;
+retry:
+	while (frames_todo) {
+		unsigned frames_now = min(frames_todo, nr_local_frames);
+
+		cgc->dma_error = 0;
+		ret = cdrom_read_block(cdi, cgc, lba, frames_now, 1, CD_FRAMESIZE_RAW);
+		if (ret) {
+			/*
+			 * Here we implement DMA size fallback
+			 */
+			if (cgc->dma_error && cdi->dma_mode == CDROM_DMA_MULTI) {
+				printk(KERN_WARNING "CDROM: falling back to "
+					"single frame DMA\n");
+				cdi->dma_mode = CDROM_DMA_SINGLE;
+				nr_local_frames = 1;
+				goto retry;
+			} else if (cgc->dma_error && cdi->dma_mode == CDROM_DMA_SINGLE) {
+				printk(KERN_WARNING "CDROM: disabled DMA\n");
+				cdi->dma_mode = CDROM_DMA_NONE;
+				goto retry;
+			}
+			goto out;
+		}
+		ret = -EFAULT;
+		if (copy_to_user(useraddr, cgc->buffer, CD_FRAMESIZE_RAW * frames_now))
+			goto out;
+		useraddr += CD_FRAMESIZE_RAW * frames_now;
+		frames_todo -= frames_now;
+		lba += frames_now;
+	}
+	ret = 0;
+out:
+	kfree(xferbuf);
+	return ret;
+}
+
 static int mmc_ioctl(struct cdrom_device_info *cdi, unsigned int cmd,
 		     unsigned long arg)
 {		

@@ -1977,57 +2078,9 @@ static int mmc_ioctl(struct cdrom_device
 		}
 	case CDROMREADAUDIO: {
 		struct cdrom_read_audio ra;
-		int lba, nr;
 
 		IOCTL_IN(arg, struct cdrom_read_audio, ra);
-
-		if (ra.addr_format == CDROM_MSF)
-			lba = msf_to_lba(ra.addr.msf.minute,
-					 ra.addr.msf.second,
-					 ra.addr.msf.frame);
-		else if (ra.addr_format == CDROM_LBA)
-			lba = ra.addr.lba;
-		else
-			return -EINVAL;
-
-		/* FIXME: we need upper bound checking, too!! */
-		if (lba < 0 || ra.nframes <= 0)
-			return -EINVAL;
-
-		/*
-		 * start with will ra.nframes size, back down if alloc fails
-		 */
-		nr = ra.nframes;
-		do {
-			cgc.buffer = kmalloc(CD_FRAMESIZE_RAW * nr, GFP_KERNEL);
-			if (cgc.buffer)
-				break;
-
-			nr >>= 1;
-		} while (nr);
-
-		if (!nr)
-			return -ENOMEM;
-
-		if (!access_ok(VERIFY_WRITE, ra.buf, ra.nframes*CD_FRAMESIZE_RAW)) {
-			kfree(cgc.buffer);
-			return -EFAULT;
-		}
-		cgc.data_direction = CGC_DATA_READ;
-		while (ra.nframes > 0) {
-			if (nr > ra.nframes)
-				nr = ra.nframes;
-
-			ret = cdrom_read_block(cdi, &cgc, lba, nr, 1, CD_FRAMESIZE_RAW);
-			if (ret)
-				break;
-			__copy_to_user(ra.buf, cgc.buffer, CD_FRAMESIZE_RAW*nr);
-			ra.buf += CD_FRAMESIZE_RAW * nr;
-			ra.nframes -= nr;
-			lba += nr;
-		}
-		kfree(cgc.buffer);
-		return ret;
+		return cdda_read_audio(cmd, cdi, &cgc, &ra);
 		}
 	case CDROMSUBCHNL: {
 		struct cdrom_subchnl q;

102 lines not on this page · raw message

@@ -111,6 +111,7 @@ struct packet_command {
 	int quiet;
 	int timeout;
 	struct request_sense *sense;
+	int do_dma;
 	unsigned char c[12];
 };
 

@@ -287,6 +287,8 @@ struct cdrom_generic_command
 	unsigned char		data_direction;
 	int			quiet;
 	int			timeout;
+	int			do_dma;		/* Try to use DMA */
+	int			dma_error;	/* A DMA_specific error occurred */
 	void			*reserved[1];
 };
 

@@ -743,10 +745,15 @@ struct cdrom_device_info {
     	char name[20];                  /* name of the device type */
 /* per-device flags */
         __u8 sanyo_slot		: 2;	/* Sanyo 3 CD changer support */
-        __u8 reserved		: 6;	/* not used yet */
+        __u8 dma_mode		: 2;	/* See below */
+        __u8 reserved		: 4;	/* not used yet */
 	struct cdrom_write_settings write;
 };
 
+#define CDROM_DMA_MULTI		0	/* Multiframe DMA (default) */
+#define CDROM_DMA_SINGLE	1	/* Single frame DMA */
+#define CDROM_DMA_NONE		2	/* Multiframe PIO */
+
 struct cdrom_device_ops {
 /* routines */
 	int (*open) (struct cdrom_device_info *, int);