[PATCH] OSS CS4232 locking fixes

Patch from: Peter Waechtler <pwaechtler@mac.com>

Addresses BUGME bug #331.  "OSS CS4232 nasty spinlock printks on boot"

The locking in some OSS modules is really lousy.
Because save_flags/cli/restore_flags could be used recursivly - the
programmers pushed the locking too far the lower level.

Because on ISA cards the register sets are usually multiplexed
you had to write to an address latch and then access the data port
in an "atomic" manner.

I suggest removing the locking from ad_read/ad_write +
ad_{enter|leave}_MCE and clamping the locks wherever the functions
are called. I hope the attached patch does that correctly.

Yes, I don't like all the timeout loops while holding the locks:
high chances that a cpu is spinning in interrupt context :(

sound/oss/ad1848.c

@@ -209,15 +209,12 @@ static void ad1848_tmr_reprogram(int dev);
 
 static int ad_read(ad1848_info * devc, int reg)
 {
-	unsigned long flags;
 	int x;
 	int timeout = 900000;
 
 	while (timeout > 0 && inb(devc->base) == 0x80)	/*Are we initializing */
 		timeout--;
 
-	spin_lock_irqsave(&devc->lock,flags);
-	
 	if(reg < 32)
 	{
 		outb(((unsigned char) (reg & 0xff) | devc->MCE_bit), io_Index_Addr(devc));
@@ -233,21 +230,17 @@ static int ad_read(ad1848_info * devc, int reg)
 		outb(((unsigned char) (xra & 0xff)), io_Indexed_Data(devc));
 		x = inb(io_Indexed_Data(devc));
 	}
-	spin_unlock_irqrestore(&devc->lock,flags);
 
 	return x;
 }
 
 static void ad_write(ad1848_info * devc, int reg, int data)
 {
-	unsigned long flags;
 	int timeout = 900000;
 
 	while (timeout > 0 && inb(devc->base) == 0x80)	/* Are we initializing */
 		timeout--;
 
-	spin_lock_irqsave(&devc->lock,flags);
-	
 	if(reg < 32)
 	{
 		outb(((unsigned char) (reg & 0xff) | devc->MCE_bit), io_Index_Addr(devc));
@@ -263,7 +256,6 @@ static void ad_write(ad1848_info * devc, int reg, int data)
 		outb(((unsigned char) (xra & 0xff)), io_Indexed_Data(devc));
 		outb((unsigned char) (data & 0xff), io_Indexed_Data(devc));
 	}
-	spin_unlock_irqrestore(&devc->lock,flags);
 }
 
 static void wait_for_calibration(ad1848_info * devc)
@@ -319,37 +311,29 @@ static void ad_unmute(ad1848_info * devc)
 
 static void ad_enter_MCE(ad1848_info * devc)
 {
-	unsigned long flags;
 	int timeout = 1000;
 	unsigned short prev;
 
 	while (timeout > 0 && inb(devc->base) == 0x80)	/*Are we initializing */
 		timeout--;
 
-	spin_lock_irqsave(&devc->lock,flags);
-
 	devc->MCE_bit = 0x40;
 	prev = inb(io_Index_Addr(devc));
 	if (prev & 0x40)
 	{
-		spin_unlock_irqrestore(&devc->lock,flags);
 		return;
 	}
 	outb((devc->MCE_bit), io_Index_Addr(devc));
-	spin_unlock_irqrestore(&devc->lock,flags);
 }
 
 static void ad_leave_MCE(ad1848_info * devc)
 {
-	unsigned long flags;
 	unsigned char prev, acal;
 	int timeout = 1000;
 
 	while (timeout > 0 && inb(devc->base) == 0x80)	/*Are we initializing */
 		timeout--;
 
-	spin_lock_irqsave(&devc->lock,flags);
-
 	acal = ad_read(devc, 9);
 
 	devc->MCE_bit = 0x00;
@@ -358,19 +342,18 @@ static void ad_leave_MCE(ad1848_info * devc)
 
 	if ((prev & 0x40) == 0)	/* Not in MCE mode */
 	{
-		spin_unlock_irqrestore(&devc->lock,flags);
 		return;
 	}
 	outb((0x00), io_Index_Addr(devc));	/* Clear the MCE bit */
 	if (acal & 0x08)	/* Auto calibration is enabled */
 		wait_for_calibration(devc);
-	spin_unlock_irqrestore(&devc->lock,flags);
 }
 
 static int ad1848_set_recmask(ad1848_info * devc, int mask)
 {
 	unsigned char   recdev;
 	int             i, n;
+	unsigned long flags;
 
 	mask &= devc->supported_rec_devices;
 
@@ -392,6 +375,7 @@ static int ad1848_set_recmask(ad1848_info * devc, int mask)
 		if (mask & (1 << i))
 			n++;
 
+	spin_lock_irqsave(&devc->lock,flags);
 	if (!soundpro) {
 		if (n == 0)
 			mask = SOUND_MASK_MIC;
@@ -460,6 +444,7 @@ static int ad1848_set_recmask(ad1848_info * devc, int mask)
 			}
 		}
 	}
+	spin_unlock_irqrestore(&devc->lock,flags);
 
 	/* Rename the mixer bits back if necessary */
 	for (i = 0; i < 32; i++)
@@ -527,6 +512,7 @@ static void ad1848_mixer_set_channel(ad1848_info *devc, int dev, int value, int
 {
 	int regoffs, muteregoffs;
 	unsigned char val, muteval;
+	unsigned long flags;
 
 	regoffs = devc->mix_devices[dev][channel].regno;
 	muteregoffs = devc->mix_devices[dev][channel].mutereg;
@@ -539,12 +525,14 @@ static void ad1848_mixer_set_channel(ad1848_info *devc, int dev, int value, int
 	else
 		change_bits(devc, &val, &val, dev, channel, value);
 
+	spin_lock_irqsave(&devc->lock,flags);
 	ad_write(devc, regoffs, val);
 	devc->saved_regs[regoffs] = val;
 	if (muteregoffs != regoffs) {
 		ad_write(devc, muteregoffs, muteval);
 		devc->saved_regs[muteregoffs] = muteval;
 	}
+	spin_unlock_irqrestore(&devc->lock,flags);
 }
 
 static int ad1848_mixer_set(ad1848_info * devc, int dev, int value)
@@ -600,6 +588,7 @@ static void ad1848_mixer_reset(ad1848_info * devc)
 {
 	int i;
 	char name[32];
+	unsigned long flags;
 
 	devc->mix_devices = &(ad1848_mix_devices[0]);
 
@@ -666,6 +655,7 @@ static void ad1848_mixer_reset(ad1848_info * devc)
 	
 	devc->mixer_output_port = devc->levels[31] | AUDIO_HEADPHONE | AUDIO_LINE_OUT;
 
+	spin_lock_irqsave(&devc->lock,flags);
 	if (!soundpro) {
 		if (devc->mixer_output_port & AUDIO_SPEAKER)
 			ad_write(devc, 26, ad_read(devc, 26) & ~0x40);	/* Unmute mono out */
@@ -679,6 +669,7 @@ static void ad1848_mixer_reset(ad1848_info * devc)
 		/* Enable surround mode and SB16 mixer */
 		ad_write(devc, 16, 0x60);
 	}
+	spin_unlock_irqrestore(&devc->lock,flags);
 }
 
 static int ad1848_mixer_ioctl(int dev, unsigned int cmd, caddr_t arg)
@@ -693,14 +684,17 @@ static int ad1848_mixer_ioctl(int dev, unsigned int cmd, caddr_t arg)
 
 		if (val != 0xffff) 
 		{
+			unsigned long flags;
 			val &= (AUDIO_SPEAKER | AUDIO_HEADPHONE | AUDIO_LINE_OUT);
 			devc->mixer_output_port = val;
 			val |= AUDIO_HEADPHONE | AUDIO_LINE_OUT;	/* Always on */
 			devc->mixer_output_port = val;
+			spin_lock_irqsave(&devc->lock,flags);
 			if (val & AUDIO_SPEAKER)
 				ad_write(devc, 26, ad_read(devc, 26) & ~0x40);	/* Unmute mono out */
 			else
 				ad_write(devc, 26, ad_read(devc, 26) | 0x40);		/* Mute mono out */
+			spin_unlock_irqrestore(&devc->lock,flags);
 		}
 		val = devc->mixer_output_port;
 		return put_user(val, (int *)arg);
@@ -985,10 +979,11 @@ static int ad1848_open(int dev, int mode)
 	devc = (ad1848_info *) audio_devs[dev]->devc;
 	portc = (ad1848_port_info *) audio_devs[dev]->portc;
 
-	spin_lock_irqsave(&devc->lock,flags);
+	/* here we don't have to protect against intr */
+	spin_lock(&devc->lock);
 	if (portc->open_mode || (devc->open_mode & mode))
 	{
-		spin_unlock_irqrestore(&devc->lock,flags);
+		spin_unlock(&devc->lock);
 		return -EBUSY;
 	}
 	devc->dual_dma = 0;
@@ -1001,17 +996,19 @@ static int ad1848_open(int dev, int mode)
 	devc->audio_mode = 0;
 	devc->open_mode |= mode;
 	portc->open_mode = mode;
+	spin_unlock(&devc->lock);
 	ad1848_trigger(dev, 0);
 
 	if (mode & OPEN_READ)
 		devc->record_dev = dev;
 	if (mode & OPEN_WRITE)
 		devc->playback_dev = dev;
-	spin_unlock_irqrestore(&devc->lock,flags);
 /*
  * Mute output until the playback really starts. This decreases clicking (hope so).
  */
+	spin_lock_irqsave(&devc->lock,flags);
 	ad_mute(devc);
+	spin_unlock_irqrestore(&devc->lock,flags);
 
 	return 0;
 }
@@ -1024,11 +1021,11 @@ static void ad1848_close(int dev)
 
 	DEB(printk("ad1848_close(void)\n"));
 
-	spin_lock_irqsave(&devc->lock,flags);
-
 	devc->intr_active = 0;
 	ad1848_halt(dev);
 
+	spin_lock_irqsave(&devc->lock,flags);
+
 	devc->audio_mode = 0;
 	devc->open_mode &= ~portc->open_mode;
 	portc->open_mode = 0;
@@ -1585,6 +1582,7 @@ int ad1848_detect(int io_base, int *ad_flags, int *osp)
 		printk(KERN_ERR "ad1848.c: Port %x not free.\n", io_base);
 		return 0;
 	}
+	spin_lock_init(&devc->lock);
 	devc->base = io_base;
 	devc->irq_ok = 0;
 	devc->timer_running = 0;
@@ -1969,7 +1967,6 @@ int ad1848_init (char *name, int io_base, int irq, int dma_playback,
 
 	ad1848_port_info *portc = NULL;
 
-	spin_lock_init(&devc->lock);
 	devc->irq = (irq > 0) ? irq : 0;
 	devc->open_mode = 0;
 	devc->timer_ticks = 0;
@@ -2112,6 +2109,7 @@ int ad1848_init (char *name, int io_base, int irq, int dma_playback,
 int ad1848_control(int cmd, int arg)
 {
 	ad1848_info *devc;
+	unsigned long flags;
 
 	if (nr_ad1848_devs < 1)
 		return -ENODEV;
@@ -2123,9 +2121,11 @@ int ad1848_control(int cmd, int arg)
 		case AD1848_SET_XTAL:	/* Change clock frequency of AD1845 (only ) */
 			if (devc->model != MD_1845 || devc->model != MD_1845_SSCAPE)
 				return -EINVAL;
+			spin_lock_irqsave(&devc->lock,flags);
 			ad_enter_MCE(devc);
 			ad_write(devc, 29, (ad_read(devc, 29) & 0x1f) | (arg << 5));
 			ad_leave_MCE(devc);
+			spin_unlock_irqrestore(&devc->lock,flags);
 			break;
 
 		case AD1848_MIXER_REROUTE:
@@ -2253,8 +2253,10 @@ void adintr(int irq, void *dev_id, struct pt_regs *dummy)
 		}
 		else if (devc->model != MD_1848)
 		{
+			spin_lock(&devc->lock);
 			alt_stat = ad_read(devc, 24);
 			ad_write(devc, 24, ad_read(devc, 24) & ~alt_stat);	/* Selective ack */
+			spin_unlock(&devc->lock);
 		}
 
 		if ((devc->open_mode & OPEN_READ) && (devc->audio_mode & PCM_ENABLE_INPUT) && (alt_stat & 0x20))
@@ -2831,11 +2833,8 @@ static int ad1848_suspend(ad1848_info *devc)
 
 static int ad1848_resume(ad1848_info *devc)
 {
-	unsigned long flags;
 	int mixer_levels[32], i;
 
-	spin_lock_irqsave(&devc->lock,flags);
-	
 	/* Thinkpad is a bit more of PITA than normal. The BIOS tends to
 	   restore it in a different config to the one we use.  Need to
 	   fix this somehow */
@@ -2851,7 +2850,7 @@ static int ad1848_resume(ad1848_info *devc)
 	if (!devc->subtype) {
 		static signed char interrupt_bits[12] = { -1, -1, -1, -1, -1, 0x00, -1, 0x08, -1, 0x10, 0x18, 0x20 };
 		static char dma_bits[4] = { 1, 2, 0, 3 };
-
+		unsigned long flags;
 		signed char bits;
 		char dma2_bit = 0;
 
@@ -2860,10 +2859,11 @@ static int ad1848_resume(ad1848_info *devc)
 		bits = interrupt_bits[devc->irq];
 		if (bits == -1) {
 			printk(KERN_ERR "MSS: Bad IRQ %d\n", devc->irq);
-			spin_unlock_irqrestore(&devc->lock,flags);
 			return -1;
 		}
 
+		spin_lock_irqsave(&devc->lock,flags);
+	
 		outb((bits | 0x40), config_port); 
 
 		if (devc->dma2 != -1 && devc->dma2 != devc->dma1)
@@ -2873,9 +2873,9 @@ static int ad1848_resume(ad1848_info *devc)
 				dma2_bit = 0x04;
 
 		outb((bits | dma_bits[devc->dma1] | dma2_bit), config_port);
+		spin_unlock_irqrestore(&devc->lock,flags);
 	}
 
-	spin_unlock_irqrestore(&devc->lock,flags);
 	return 0;
 }