[ALSA] ice1724 - Fix IRQ lock-up with MPU access

The sound boards with VT1724 and compatible chips may lock up when
MPU401 is accessed together with the PCM streaming.
This patch fixes the problem.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 81 insertions, 14 deletions

diff --git a/sound/pci/ice1712/ice1724.c b/sound/pci/ice1712/ice1724.c
index 13ea94f317cb..4490422fb930 100644
--- a/sound/pci/ice1712/ice1724.c
+++ b/sound/pci/ice1712/ice1724.c
@@ -223,6 +223,32 @@ static unsigned int snd_vt1724_get_gpio_data(struct snd_ice1712 *ice)
 }
 
 /*
+ * MPU401 accessor
+ */
+static unsigned char snd_vt1724_mpu401_read(struct snd_mpu401 *mpu,
+                                            unsigned long addr)
+{
+        /* fix status bits to the standard position */
+        /* only RX_EMPTY and TX_FULL are checked */
+        if (addr == MPU401C(mpu))
+                return (inb(addr) & 0x0c) << 4;
+        else
+                return inb(addr);
+}
+
+static void snd_vt1724_mpu401_write(struct snd_mpu401 *mpu,
+                                    unsigned char data, unsigned long addr)
+{
+        if (addr == MPU401C(mpu)) {
+                if (data == MPU401_ENTER_UART)
+                        outb(0x01, addr);
+                /* what else? */
+        } else
+                outb(data, addr);
+}
+
+
+/*
  *  Interrupt handler
  */
 
@@ -230,24 +256,53 @@ static irqreturn_t snd_vt1724_interrupt(int irq, void *dev_id)
 {
         struct snd_ice1712 *ice = dev_id;
         unsigned char status;
+        unsigned char status_mask =
+                VT1724_IRQ_MPU_RX | VT1724_IRQ_MPU_TX | VT1724_IRQ_MTPCM;
         int handled = 0;
+#ifdef CONFIG_SND_DEBUG
+        int timeout = 0;
+#endif
 
         while (1) {
                 status = inb(ICEREG1724(ice, IRQSTAT));
+                status &= status_mask;
                 if (status == 0)
                         break;
-
+#ifdef CONFIG_SND_DEBUG
+                if (++timeout > 10) {
+                        printk(KERN_ERR
+                               "ice1724: Too long irq loop, status = 0x%x\n",
+                               status);
+                        break;
+                }
+#endif
                 handled = 1;            
-                /* these should probably be separated at some point, 
-                 * but as we don't currently have MPU support on the board
-                 * I will leave it
-                 */
-                if ((status & VT1724_IRQ_MPU_RX)||(status & VT1724_IRQ_MPU_TX)) {
+                if (status & VT1724_IRQ_MPU_TX) {
                         if (ice->rmidi[0])
-                                snd_mpu401_uart_interrupt(irq, ice->rmidi[0]->private_data);
-                        outb(status & (VT1724_IRQ_MPU_RX|VT1724_IRQ_MPU_TX), ICEREG1724(ice, IRQSTAT));
-                        status &= ~(VT1724_IRQ_MPU_RX|VT1724_IRQ_MPU_TX);
+                                snd_mpu401_uart_interrupt_tx(irq,
+                                        ice->rmidi[0]->private_data);
+                        else /* disable TX to be sure */
+                                outb(inb(ICEREG1724(ice, IRQMASK)) |
+                                     VT1724_IRQ_MPU_TX,
+                                     ICEREG1724(ice, IRQMASK));
+                        /* Due to mysterical reasons, MPU_TX is always
+                         * generated (and can't be cleared) when a PCM
+                         * playback is going.  So let's ignore at the
+                         * next loop.
+                         */
+                        status_mask &= ~VT1724_IRQ_MPU_TX;
+                }
+                if (status & VT1724_IRQ_MPU_RX) {
+                        if (ice->rmidi[0])
+                                snd_mpu401_uart_interrupt(irq,
+                                        ice->rmidi[0]->private_data);
+                        else /* disable RX to be sure */
+                                outb(inb(ICEREG1724(ice, IRQMASK)) |
+                                     VT1724_IRQ_MPU_RX,
+                                     ICEREG1724(ice, IRQMASK));
                 }
+                /* ack MPU irq */
+                outb(status, ICEREG1724(ice, IRQSTAT));
                 if (status & VT1724_IRQ_MTPCM) {
                         /*
                          * Multi-track PCM
@@ -2236,10 +2291,7 @@ static int __devinit snd_vt1724_create(struct snd_card *card,
         }
 
         /* unmask used interrupts */
-        if (! (ice->eeprom.data[ICE_EEP2_SYSCONF] & VT1724_CFG_MPU401))
-                mask = VT1724_IRQ_MPU_RX | VT1724_IRQ_MPU_TX;
-        else
-                mask = 0;
+        mask = VT1724_IRQ_MPU_RX | VT1724_IRQ_MPU_TX;
         outb(mask, ICEREG1724(ice, IRQMASK));
         /* don't handle FIFO overrun/underruns (just yet),
          * since they cause machine lockups
@@ -2373,14 +2425,29 @@ static int __devinit snd_vt1724_probe(struct pci_dev *pci,
 
         if (! c->no_mpu401) {
                 if (ice->eeprom.data[ICE_EEP2_SYSCONF] & VT1724_CFG_MPU401) {
+                        struct snd_mpu401 *mpu;
                         if ((err = snd_mpu401_uart_new(card, 0, MPU401_HW_ICE1712,
                                                        ICEREG1724(ice, MPU_CTRL),
-                                                       MPU401_INFO_INTEGRATED,
+                                                       (MPU401_INFO_INTEGRATED |
+                                                        MPU401_INFO_TX_IRQ),
                                                        ice->irq, 0,
                                                        &ice->rmidi[0])) < 0) {
                                 snd_card_free(card);
                                 return err;
                         }
+                        mpu = ice->rmidi[0]->private_data;
+                        mpu->read = snd_vt1724_mpu401_read;
+                        mpu->write = snd_vt1724_mpu401_write;
+                        /* unmask MPU RX/TX irqs */
+                        outb(inb(ICEREG1724(ice, IRQMASK)) &
+                             ~(VT1724_IRQ_MPU_RX | VT1724_IRQ_MPU_TX),
+                             ICEREG1724(ice, IRQMASK));
+#if 0 /* for testing */
+                        /* set watermarks */
+                        outb(VT1724_MPU_RX_FIFO | 0x1,
+                             ICEREG1724(ice, MPU_FIFO_WM));
+                        outb(0x1, ICEREG1724(ice, MPU_FIFO_WM));
+#endif
                 }
         }