Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / sound / drivers / serial-u16550.c
diff --git a/kernel/sound/drivers/serial-u16550.c b/kernel/sound/drivers/serial-u16550.c
new file mode 100644 (file)
index 0000000..1927b89
--- /dev/null
@@ -0,0 +1,1045 @@
+/*
+ *   serial.c
+ *   Copyright (c) by Jaroslav Kysela <perex@perex.cz>,
+ *                    Isaku Yamahata <yamahata@private.email.ne.jp>,
+ *                   George Hansper <ghansper@apana.org.au>,
+ *                   Hannu Savolainen
+ *
+ *   This code is based on the code from ALSA 0.5.9, but heavily rewritten.
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ *
+ * Sat Mar 31 17:27:57 PST 2001 tim.mann@compaq.com 
+ *      Added support for the Midiator MS-124T and for the MS-124W in
+ *      Single Addressed (S/A) or Multiple Burst (M/B) mode, with
+ *      power derived either parasitically from the serial port or
+ *      from a separate power supply.
+ *
+ *      More documentation can be found in serial-u16550.txt.
+ */
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/ioport.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <sound/core.h>
+#include <sound/rawmidi.h>
+#include <sound/initval.h>
+
+#include <linux/serial_reg.h>
+#include <linux/jiffies.h>
+
+MODULE_DESCRIPTION("MIDI serial u16550");
+MODULE_LICENSE("GPL");
+MODULE_SUPPORTED_DEVICE("{{ALSA, MIDI serial u16550}}");
+
+#define SNDRV_SERIAL_SOUNDCANVAS 0 /* Roland Soundcanvas; F5 NN selects part */
+#define SNDRV_SERIAL_MS124T 1      /* Midiator MS-124T */
+#define SNDRV_SERIAL_MS124W_SA 2   /* Midiator MS-124W in S/A mode */
+#define SNDRV_SERIAL_MS124W_MB 3   /* Midiator MS-124W in M/B mode */
+#define SNDRV_SERIAL_GENERIC 4     /* Generic Interface */
+#define SNDRV_SERIAL_MAX_ADAPTOR SNDRV_SERIAL_GENERIC
+static char *adaptor_names[] = {
+       "Soundcanvas",
+        "MS-124T",
+       "MS-124W S/A",
+       "MS-124W M/B",
+       "Generic"
+};
+
+#define SNDRV_SERIAL_NORMALBUFF 0 /* Normal blocking buffer operation */
+#define SNDRV_SERIAL_DROPBUFF   1 /* Non-blocking discard operation */
+
+static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;     /* Index 0-MAX */
+static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;      /* ID for this card */
+static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE; /* Enable this card */
+static long port[SNDRV_CARDS] = SNDRV_DEFAULT_PORT; /* 0x3f8,0x2f8,0x3e8,0x2e8 */
+static int irq[SNDRV_CARDS] = SNDRV_DEFAULT_IRQ;       /* 3,4,5,7,9,10,11,14,15 */
+static int speed[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 38400}; /* 9600,19200,38400,57600,115200 */
+static int base[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 115200}; /* baud base */
+static int outs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};         /* 1 to 16 */
+static int ins[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1}; /* 1 to 16 */
+static int adaptor[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = SNDRV_SERIAL_SOUNDCANVAS};
+static bool droponfull[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS -1)] = SNDRV_SERIAL_NORMALBUFF };
+
+module_param_array(index, int, NULL, 0444);
+MODULE_PARM_DESC(index, "Index value for Serial MIDI.");
+module_param_array(id, charp, NULL, 0444);
+MODULE_PARM_DESC(id, "ID string for Serial MIDI.");
+module_param_array(enable, bool, NULL, 0444);
+MODULE_PARM_DESC(enable, "Enable UART16550A chip.");
+module_param_array(port, long, NULL, 0444);
+MODULE_PARM_DESC(port, "Port # for UART16550A chip.");
+module_param_array(irq, int, NULL, 0444);
+MODULE_PARM_DESC(irq, "IRQ # for UART16550A chip.");
+module_param_array(speed, int, NULL, 0444);
+MODULE_PARM_DESC(speed, "Speed in bauds.");
+module_param_array(base, int, NULL, 0444);
+MODULE_PARM_DESC(base, "Base for divisor in bauds.");
+module_param_array(outs, int, NULL, 0444);
+MODULE_PARM_DESC(outs, "Number of MIDI outputs.");
+module_param_array(ins, int, NULL, 0444);
+MODULE_PARM_DESC(ins, "Number of MIDI inputs.");
+module_param_array(droponfull, bool, NULL, 0444);
+MODULE_PARM_DESC(droponfull, "Flag to enable drop-on-full buffer mode");
+
+module_param_array(adaptor, int, NULL, 0444);
+MODULE_PARM_DESC(adaptor, "Type of adaptor.");
+
+/*#define SNDRV_SERIAL_MS124W_MB_NOCOMBO 1*/  /* Address outs as 0-3 instead of bitmap */
+
+#define SNDRV_SERIAL_MAX_OUTS  16              /* max 64, min 16 */
+#define SNDRV_SERIAL_MAX_INS   16              /* max 64, min 16 */
+
+#define TX_BUFF_SIZE           (1<<15)         /* Must be 2^n */
+#define TX_BUFF_MASK           (TX_BUFF_SIZE - 1)
+
+#define SERIAL_MODE_NOT_OPENED                 (0)
+#define SERIAL_MODE_INPUT_OPEN         (1 << 0)
+#define SERIAL_MODE_OUTPUT_OPEN                (1 << 1)
+#define SERIAL_MODE_INPUT_TRIGGERED    (1 << 2)
+#define SERIAL_MODE_OUTPUT_TRIGGERED   (1 << 3)
+
+struct snd_uart16550 {
+       struct snd_card *card;
+       struct snd_rawmidi *rmidi;
+       struct snd_rawmidi_substream *midi_output[SNDRV_SERIAL_MAX_OUTS];
+       struct snd_rawmidi_substream *midi_input[SNDRV_SERIAL_MAX_INS];
+
+       int filemode;           /* open status of file */
+
+       spinlock_t open_lock;
+
+       int irq;
+
+       unsigned long base;
+       struct resource *res_base;
+
+       unsigned int speed;
+       unsigned int speed_base;
+       unsigned char divisor;
+
+       unsigned char old_divisor_lsb;
+       unsigned char old_divisor_msb;
+       unsigned char old_line_ctrl_reg;
+
+       /* parameter for using of write loop */
+       short int fifo_limit;   /* used in uart16550 */
+        short int fifo_count;  /* used in uart16550 */
+
+       /* type of adaptor */
+       int adaptor;
+
+       /* inputs */
+       int prev_in;
+       unsigned char rstatus;
+
+       /* outputs */
+       int prev_out;
+       unsigned char prev_status[SNDRV_SERIAL_MAX_OUTS];
+
+       /* write buffer and its writing/reading position */
+       unsigned char tx_buff[TX_BUFF_SIZE];
+       int buff_in_count;
+        int buff_in;
+        int buff_out;
+        int drop_on_full;
+
+       /* wait timer */
+       unsigned int timer_running:1;
+       struct timer_list buffer_timer;
+
+};
+
+static struct platform_device *devices[SNDRV_CARDS];
+
+static inline void snd_uart16550_add_timer(struct snd_uart16550 *uart)
+{
+       if (!uart->timer_running) {
+               /* timer 38600bps * 10bit * 16byte */
+               mod_timer(&uart->buffer_timer, jiffies + (HZ + 255) / 256);
+               uart->timer_running = 1;
+       }
+}
+
+static inline void snd_uart16550_del_timer(struct snd_uart16550 *uart)
+{
+       if (uart->timer_running) {
+               del_timer(&uart->buffer_timer);
+               uart->timer_running = 0;
+       }
+}
+
+/* This macro is only used in snd_uart16550_io_loop */
+static inline void snd_uart16550_buffer_output(struct snd_uart16550 *uart)
+{
+       unsigned short buff_out = uart->buff_out;
+       if (uart->buff_in_count > 0) {
+               outb(uart->tx_buff[buff_out], uart->base + UART_TX);
+               uart->fifo_count++;
+               buff_out++;
+               buff_out &= TX_BUFF_MASK;
+               uart->buff_out = buff_out;
+               uart->buff_in_count--;
+       }
+}
+
+/* This loop should be called with interrupts disabled
+ * We don't want to interrupt this, 
+ * as we're already handling an interrupt 
+ */
+static void snd_uart16550_io_loop(struct snd_uart16550 * uart)
+{
+       unsigned char c, status;
+       int substream;
+
+       /* recall previous stream */
+       substream = uart->prev_in;
+
+       /* Read Loop */
+       while ((status = inb(uart->base + UART_LSR)) & UART_LSR_DR) {
+               /* while receive data ready */
+               c = inb(uart->base + UART_RX);
+
+               /* keep track of last status byte */
+               if (c & 0x80)
+                       uart->rstatus = c;
+
+               /* handle stream switch */
+               if (uart->adaptor == SNDRV_SERIAL_GENERIC) {
+                       if (uart->rstatus == 0xf5) {
+                               if (c <= SNDRV_SERIAL_MAX_INS && c > 0)
+                                       substream = c - 1;
+                               if (c != 0xf5)
+                                       /* prevent future bytes from being
+                                          interpreted as streams */
+                                       uart->rstatus = 0;
+                       } else if ((uart->filemode & SERIAL_MODE_INPUT_OPEN)
+                                  && uart->midi_input[substream])
+                               snd_rawmidi_receive(uart->midi_input[substream],
+                                                   &c, 1);
+               } else if ((uart->filemode & SERIAL_MODE_INPUT_OPEN) &&
+                          uart->midi_input[substream])
+                       snd_rawmidi_receive(uart->midi_input[substream], &c, 1);
+
+               if (status & UART_LSR_OE)
+                       snd_printk(KERN_WARNING
+                                  "%s: Overrun on device at 0x%lx\n",
+                              uart->rmidi->name, uart->base);
+       }
+
+       /* remember the last stream */
+       uart->prev_in = substream;
+
+       /* no need of check SERIAL_MODE_OUTPUT_OPEN because if not,
+          buffer is never filled. */
+       /* Check write status */
+       if (status & UART_LSR_THRE)
+               uart->fifo_count = 0;
+       if (uart->adaptor == SNDRV_SERIAL_MS124W_SA
+          || uart->adaptor == SNDRV_SERIAL_GENERIC) {
+               /* Can't use FIFO, must send only when CTS is true */
+               status = inb(uart->base + UART_MSR);
+               while (uart->fifo_count == 0 && (status & UART_MSR_CTS) &&
+                      uart->buff_in_count > 0) {
+                      snd_uart16550_buffer_output(uart);
+                      status = inb(uart->base + UART_MSR);
+               }
+       } else {
+               /* Write loop */
+               while (uart->fifo_count < uart->fifo_limit /* Can we write ? */
+                      && uart->buff_in_count > 0)      /* Do we want to? */
+                       snd_uart16550_buffer_output(uart);
+       }
+       if (uart->irq < 0 && uart->buff_in_count > 0)
+               snd_uart16550_add_timer(uart);
+}
+
+/* NOTES ON SERVICING INTERUPTS
+ * ---------------------------
+ * After receiving a interrupt, it is important to indicate to the UART that
+ * this has been done. 
+ * For a Rx interrupt, this is done by reading the received byte.
+ * For a Tx interrupt this is done by either:
+ * a) Writing a byte
+ * b) Reading the IIR
+ * It is particularly important to read the IIR if a Tx interrupt is received
+ * when there is no data in tx_buff[], as in this case there no other
+ * indication that the interrupt has been serviced, and it remains outstanding
+ * indefinitely. This has the curious side effect that and no further interrupts
+ * will be generated from this device AT ALL!!.
+ * It is also desirable to clear outstanding interrupts when the device is
+ * opened/closed.
+ *
+ *
+ * Note that some devices need OUT2 to be set before they will generate
+ * interrupts at all. (Possibly tied to an internal pull-up on CTS?)
+ */
+static irqreturn_t snd_uart16550_interrupt(int irq, void *dev_id)
+{
+       struct snd_uart16550 *uart;
+
+       uart = dev_id;
+       spin_lock(&uart->open_lock);
+       if (uart->filemode == SERIAL_MODE_NOT_OPENED) {
+               spin_unlock(&uart->open_lock);
+               return IRQ_NONE;
+       }
+       /* indicate to the UART that the interrupt has been serviced */
+       inb(uart->base + UART_IIR);
+       snd_uart16550_io_loop(uart);
+       spin_unlock(&uart->open_lock);
+       return IRQ_HANDLED;
+}
+
+/* When the polling mode, this function calls snd_uart16550_io_loop. */
+static void snd_uart16550_buffer_timer(unsigned long data)
+{
+       unsigned long flags;
+       struct snd_uart16550 *uart;
+
+       uart = (struct snd_uart16550 *)data;
+       spin_lock_irqsave(&uart->open_lock, flags);
+       snd_uart16550_del_timer(uart);
+       snd_uart16550_io_loop(uart);
+       spin_unlock_irqrestore(&uart->open_lock, flags);
+}
+
+/*
+ *  this method probes, if an uart sits on given port
+ *  return 0 if found
+ *  return negative error if not found
+ */
+static int snd_uart16550_detect(struct snd_uart16550 *uart)
+{
+       unsigned long io_base = uart->base;
+       int ok;
+       unsigned char c;
+
+       /* Do some vague tests for the presence of the uart */
+       if (io_base == 0 || io_base == SNDRV_AUTO_PORT) {
+               return -ENODEV; /* Not configured */
+       }
+
+       uart->res_base = request_region(io_base, 8, "Serial MIDI");
+       if (uart->res_base == NULL) {
+               snd_printk(KERN_ERR "u16550: can't grab port 0x%lx\n", io_base);
+               return -EBUSY;
+       }
+
+       /* uart detected unless one of the following tests should fail */
+       ok = 1;
+       /* 8 data-bits, 1 stop-bit, parity off, DLAB = 0 */
+       outb(UART_LCR_WLEN8, io_base + UART_LCR); /* Line Control Register */
+       c = inb(io_base + UART_IER);
+       /* The top four bits of the IER should always == 0 */
+       if ((c & 0xf0) != 0)
+               ok = 0;         /* failed */
+
+       outb(0xaa, io_base + UART_SCR);
+       /* Write arbitrary data into the scratch reg */
+       c = inb(io_base + UART_SCR);
+       /* If it comes back, it's OK */
+       if (c != 0xaa)
+               ok = 0;         /* failed */
+
+       outb(0x55, io_base + UART_SCR);
+       /* Write arbitrary data into the scratch reg */
+       c = inb(io_base + UART_SCR);
+       /* If it comes back, it's OK */
+       if (c != 0x55)
+               ok = 0;         /* failed */
+
+       return ok;
+}
+
+static void snd_uart16550_do_open(struct snd_uart16550 * uart)
+{
+       char byte;
+
+       /* Initialize basic variables */
+       uart->buff_in_count = 0;
+       uart->buff_in = 0;
+       uart->buff_out = 0;
+       uart->fifo_limit = 1;
+       uart->fifo_count = 0;
+       uart->timer_running = 0;
+
+       outb(UART_FCR_ENABLE_FIFO       /* Enable FIFO's (if available) */
+            | UART_FCR_CLEAR_RCVR      /* Clear receiver FIFO */
+            | UART_FCR_CLEAR_XMIT      /* Clear transmitter FIFO */
+            | UART_FCR_TRIGGER_4       /* Set FIFO trigger at 4-bytes */
+       /* NOTE: interrupt generated after T=(time)4-bytes
+        * if less than UART_FCR_TRIGGER bytes received
+        */
+            ,uart->base + UART_FCR);   /* FIFO Control Register */
+
+       if ((inb(uart->base + UART_IIR) & 0xf0) == 0xc0)
+               uart->fifo_limit = 16;
+       if (uart->divisor != 0) {
+               uart->old_line_ctrl_reg = inb(uart->base + UART_LCR);
+               outb(UART_LCR_DLAB      /* Divisor latch access bit */
+                    ,uart->base + UART_LCR);   /* Line Control Register */
+               uart->old_divisor_lsb = inb(uart->base + UART_DLL);
+               uart->old_divisor_msb = inb(uart->base + UART_DLM);
+
+               outb(uart->divisor
+                    ,uart->base + UART_DLL);   /* Divisor Latch Low */
+               outb(0
+                    ,uart->base + UART_DLM);   /* Divisor Latch High */
+               /* DLAB is reset to 0 in next outb() */
+       }
+       /* Set serial parameters (parity off, etc) */
+       outb(UART_LCR_WLEN8     /* 8 data-bits */
+            | 0                /* 1 stop-bit */
+            | 0                /* parity off */
+            | 0                /* DLAB = 0 */
+            ,uart->base + UART_LCR);   /* Line Control Register */
+
+       switch (uart->adaptor) {
+       default:
+               outb(UART_MCR_RTS       /* Set Request-To-Send line active */
+                    | UART_MCR_DTR     /* Set Data-Terminal-Ready line active */
+                    | UART_MCR_OUT2    /* Set OUT2 - not always required, but when
+                                        * it is, it is ESSENTIAL for enabling interrupts
+                                */
+                    ,uart->base + UART_MCR);   /* Modem Control Register */
+               break;
+       case SNDRV_SERIAL_MS124W_SA:
+       case SNDRV_SERIAL_MS124W_MB:
+               /* MS-124W can draw power from RTS and DTR if they
+                  are in opposite states. */ 
+               outb(UART_MCR_RTS | (0&UART_MCR_DTR) | UART_MCR_OUT2,
+                    uart->base + UART_MCR);
+               break;
+       case SNDRV_SERIAL_MS124T:
+               /* MS-124T can draw power from RTS and/or DTR (preferably
+                  both) if they are both asserted. */
+               outb(UART_MCR_RTS | UART_MCR_DTR | UART_MCR_OUT2,
+                    uart->base + UART_MCR);
+               break;
+       }
+
+       if (uart->irq < 0) {
+               byte = (0 & UART_IER_RDI)       /* Disable Receiver data interrupt */
+                   |(0 & UART_IER_THRI)        /* Disable Transmitter holding register empty interrupt */
+                   ;
+       } else if (uart->adaptor == SNDRV_SERIAL_MS124W_SA) {
+               byte = UART_IER_RDI     /* Enable Receiver data interrupt */
+                   | UART_IER_MSI      /* Enable Modem status interrupt */
+                   ;
+       } else if (uart->adaptor == SNDRV_SERIAL_GENERIC) {
+               byte = UART_IER_RDI     /* Enable Receiver data interrupt */
+                   | UART_IER_MSI      /* Enable Modem status interrupt */
+                   | UART_IER_THRI     /* Enable Transmitter holding register empty interrupt */
+                   ;
+       } else {
+               byte = UART_IER_RDI     /* Enable Receiver data interrupt */
+                   | UART_IER_THRI     /* Enable Transmitter holding register empty interrupt */
+                   ;
+       }
+       outb(byte, uart->base + UART_IER);      /* Interrupt enable Register */
+
+       inb(uart->base + UART_LSR);     /* Clear any pre-existing overrun indication */
+       inb(uart->base + UART_IIR);     /* Clear any pre-existing transmit interrupt */
+       inb(uart->base + UART_RX);      /* Clear any pre-existing receive interrupt */
+}
+
+static void snd_uart16550_do_close(struct snd_uart16550 * uart)
+{
+       if (uart->irq < 0)
+               snd_uart16550_del_timer(uart);
+
+       /* NOTE: may need to disable interrupts before de-registering out handler.
+        * For now, the consequences are harmless.
+        */
+
+       outb((0 & UART_IER_RDI)         /* Disable Receiver data interrupt */
+            |(0 & UART_IER_THRI)       /* Disable Transmitter holding register empty interrupt */
+            ,uart->base + UART_IER);   /* Interrupt enable Register */
+
+       switch (uart->adaptor) {
+       default:
+               outb((0 & UART_MCR_RTS)         /* Deactivate Request-To-Send line  */
+                    |(0 & UART_MCR_DTR)        /* Deactivate Data-Terminal-Ready line */
+                    |(0 & UART_MCR_OUT2)       /* Deactivate OUT2 */
+                    ,uart->base + UART_MCR);   /* Modem Control Register */
+         break;
+       case SNDRV_SERIAL_MS124W_SA:
+       case SNDRV_SERIAL_MS124W_MB:
+               /* MS-124W can draw power from RTS and DTR if they
+                  are in opposite states; leave it powered. */ 
+               outb(UART_MCR_RTS | (0&UART_MCR_DTR) | (0&UART_MCR_OUT2),
+                    uart->base + UART_MCR);
+               break;
+       case SNDRV_SERIAL_MS124T:
+               /* MS-124T can draw power from RTS and/or DTR (preferably
+                  both) if they are both asserted; leave it powered. */
+               outb(UART_MCR_RTS | UART_MCR_DTR | (0&UART_MCR_OUT2),
+                    uart->base + UART_MCR);
+               break;
+       }
+
+       inb(uart->base + UART_IIR);     /* Clear any outstanding interrupts */
+
+       /* Restore old divisor */
+       if (uart->divisor != 0) {
+               outb(UART_LCR_DLAB              /* Divisor latch access bit */
+                    ,uart->base + UART_LCR);   /* Line Control Register */
+               outb(uart->old_divisor_lsb
+                    ,uart->base + UART_DLL);   /* Divisor Latch Low */
+               outb(uart->old_divisor_msb
+                    ,uart->base + UART_DLM);   /* Divisor Latch High */
+               /* Restore old LCR (data bits, stop bits, parity, DLAB) */
+               outb(uart->old_line_ctrl_reg
+                    ,uart->base + UART_LCR);   /* Line Control Register */
+       }
+}
+
+static int snd_uart16550_input_open(struct snd_rawmidi_substream *substream)
+{
+       unsigned long flags;
+       struct snd_uart16550 *uart = substream->rmidi->private_data;
+
+       spin_lock_irqsave(&uart->open_lock, flags);
+       if (uart->filemode == SERIAL_MODE_NOT_OPENED)
+               snd_uart16550_do_open(uart);
+       uart->filemode |= SERIAL_MODE_INPUT_OPEN;
+       uart->midi_input[substream->number] = substream;
+       spin_unlock_irqrestore(&uart->open_lock, flags);
+       return 0;
+}
+
+static int snd_uart16550_input_close(struct snd_rawmidi_substream *substream)
+{
+       unsigned long flags;
+       struct snd_uart16550 *uart = substream->rmidi->private_data;
+
+       spin_lock_irqsave(&uart->open_lock, flags);
+       uart->filemode &= ~SERIAL_MODE_INPUT_OPEN;
+       uart->midi_input[substream->number] = NULL;
+       if (uart->filemode == SERIAL_MODE_NOT_OPENED)
+               snd_uart16550_do_close(uart);
+       spin_unlock_irqrestore(&uart->open_lock, flags);
+       return 0;
+}
+
+static void snd_uart16550_input_trigger(struct snd_rawmidi_substream *substream,
+                                       int up)
+{
+       unsigned long flags;
+       struct snd_uart16550 *uart = substream->rmidi->private_data;
+
+       spin_lock_irqsave(&uart->open_lock, flags);
+       if (up)
+               uart->filemode |= SERIAL_MODE_INPUT_TRIGGERED;
+       else
+               uart->filemode &= ~SERIAL_MODE_INPUT_TRIGGERED;
+       spin_unlock_irqrestore(&uart->open_lock, flags);
+}
+
+static int snd_uart16550_output_open(struct snd_rawmidi_substream *substream)
+{
+       unsigned long flags;
+       struct snd_uart16550 *uart = substream->rmidi->private_data;
+
+       spin_lock_irqsave(&uart->open_lock, flags);
+       if (uart->filemode == SERIAL_MODE_NOT_OPENED)
+               snd_uart16550_do_open(uart);
+       uart->filemode |= SERIAL_MODE_OUTPUT_OPEN;
+       uart->midi_output[substream->number] = substream;
+       spin_unlock_irqrestore(&uart->open_lock, flags);
+       return 0;
+};
+
+static int snd_uart16550_output_close(struct snd_rawmidi_substream *substream)
+{
+       unsigned long flags;
+       struct snd_uart16550 *uart = substream->rmidi->private_data;
+
+       spin_lock_irqsave(&uart->open_lock, flags);
+       uart->filemode &= ~SERIAL_MODE_OUTPUT_OPEN;
+       uart->midi_output[substream->number] = NULL;
+       if (uart->filemode == SERIAL_MODE_NOT_OPENED)
+               snd_uart16550_do_close(uart);
+       spin_unlock_irqrestore(&uart->open_lock, flags);
+       return 0;
+};
+
+static inline int snd_uart16550_buffer_can_write(struct snd_uart16550 *uart,
+                                                int Num)
+{
+       if (uart->buff_in_count + Num < TX_BUFF_SIZE)
+               return 1;
+       else
+               return 0;
+}
+
+static inline int snd_uart16550_write_buffer(struct snd_uart16550 *uart,
+                                            unsigned char byte)
+{
+       unsigned short buff_in = uart->buff_in;
+       if (uart->buff_in_count < TX_BUFF_SIZE) {
+               uart->tx_buff[buff_in] = byte;
+               buff_in++;
+               buff_in &= TX_BUFF_MASK;
+               uart->buff_in = buff_in;
+               uart->buff_in_count++;
+               if (uart->irq < 0) /* polling mode */
+                       snd_uart16550_add_timer(uart);
+               return 1;
+       } else
+               return 0;
+}
+
+static int snd_uart16550_output_byte(struct snd_uart16550 *uart,
+                                    struct snd_rawmidi_substream *substream,
+                                    unsigned char midi_byte)
+{
+       if (uart->buff_in_count == 0                    /* Buffer empty? */
+           && ((uart->adaptor != SNDRV_SERIAL_MS124W_SA &&
+           uart->adaptor != SNDRV_SERIAL_GENERIC) ||
+               (uart->fifo_count == 0                  /* FIFO empty? */
+                && (inb(uart->base + UART_MSR) & UART_MSR_CTS)))) { /* CTS? */
+
+               /* Tx Buffer Empty - try to write immediately */
+               if ((inb(uart->base + UART_LSR) & UART_LSR_THRE) != 0) {
+                       /* Transmitter holding register (and Tx FIFO) empty */
+                       uart->fifo_count = 1;
+                       outb(midi_byte, uart->base + UART_TX);
+               } else {
+                       if (uart->fifo_count < uart->fifo_limit) {
+                               uart->fifo_count++;
+                               outb(midi_byte, uart->base + UART_TX);
+                       } else {
+                               /* Cannot write (buffer empty) -
+                                * put char in buffer */
+                               snd_uart16550_write_buffer(uart, midi_byte);
+                       }
+               }
+       } else {
+               if (!snd_uart16550_write_buffer(uart, midi_byte)) {
+                       snd_printk(KERN_WARNING
+                                  "%s: Buffer overrun on device at 0x%lx\n",
+                                  uart->rmidi->name, uart->base);
+                       return 0;
+               }
+       }
+
+       return 1;
+}
+
+static void snd_uart16550_output_write(struct snd_rawmidi_substream *substream)
+{
+       unsigned long flags;
+       unsigned char midi_byte, addr_byte;
+       struct snd_uart16550 *uart = substream->rmidi->private_data;
+       char first;
+       static unsigned long lasttime = 0;
+       
+       /* Interrupts are disabled during the updating of the tx_buff,
+        * since it is 'bad' to have two processes updating the same
+        * variables (ie buff_in & buff_out)
+        */
+
+       spin_lock_irqsave(&uart->open_lock, flags);
+
+       if (uart->irq < 0)      /* polling */
+               snd_uart16550_io_loop(uart);
+
+       if (uart->adaptor == SNDRV_SERIAL_MS124W_MB) {
+               while (1) {
+                       /* buffer full? */
+                       /* in this mode we need two bytes of space */
+                       if (uart->buff_in_count > TX_BUFF_SIZE - 2)
+                               break;
+                       if (snd_rawmidi_transmit(substream, &midi_byte, 1) != 1)
+                               break;
+#ifdef SNDRV_SERIAL_MS124W_MB_NOCOMBO
+                       /* select exactly one of the four ports */
+                       addr_byte = (1 << (substream->number + 4)) | 0x08;
+#else
+                       /* select any combination of the four ports */
+                       addr_byte = (substream->number << 4) | 0x08;
+                       /* ...except none */
+                       if (addr_byte == 0x08)
+                               addr_byte = 0xf8;
+#endif
+                       snd_uart16550_output_byte(uart, substream, addr_byte);
+                       /* send midi byte */
+                       snd_uart16550_output_byte(uart, substream, midi_byte);
+               }
+       } else {
+               first = 0;
+               while (snd_rawmidi_transmit_peek(substream, &midi_byte, 1) == 1) {
+                       /* Also send F5 after 3 seconds with no data
+                        * to handle device disconnect */
+                       if (first == 0 &&
+                           (uart->adaptor == SNDRV_SERIAL_SOUNDCANVAS ||
+                            uart->adaptor == SNDRV_SERIAL_GENERIC) &&
+                           (uart->prev_out != substream->number ||
+                            time_after(jiffies, lasttime + 3*HZ))) {
+
+                               if (snd_uart16550_buffer_can_write(uart, 3)) {
+                                       /* Roland Soundcanvas part selection */
+                                       /* If this substream of the data is
+                                        * different previous substream
+                                        * in this uart, send the change part
+                                        * event
+                                        */
+                                       uart->prev_out = substream->number;
+                                       /* change part */
+                                       snd_uart16550_output_byte(uart, substream,
+                                                                 0xf5);
+                                       /* data */
+                                       snd_uart16550_output_byte(uart, substream,
+                                                                 uart->prev_out + 1);
+                                       /* If midi_byte is a data byte,
+                                        * send the previous status byte */
+                                       if (midi_byte < 0x80 &&
+                                           uart->adaptor == SNDRV_SERIAL_SOUNDCANVAS)
+                                               snd_uart16550_output_byte(uart, substream, uart->prev_status[uart->prev_out]);
+                               } else if (!uart->drop_on_full)
+                                       break;
+
+                       }
+
+                       /* send midi byte */
+                       if (!snd_uart16550_output_byte(uart, substream, midi_byte) &&
+                           !uart->drop_on_full )
+                               break;
+
+                       if (midi_byte >= 0x80 && midi_byte < 0xf0)
+                               uart->prev_status[uart->prev_out] = midi_byte;
+                       first = 1;
+
+                       snd_rawmidi_transmit_ack( substream, 1 );
+               }
+               lasttime = jiffies;
+       }
+       spin_unlock_irqrestore(&uart->open_lock, flags);
+}
+
+static void snd_uart16550_output_trigger(struct snd_rawmidi_substream *substream,
+                                        int up)
+{
+       unsigned long flags;
+       struct snd_uart16550 *uart = substream->rmidi->private_data;
+
+       spin_lock_irqsave(&uart->open_lock, flags);
+       if (up)
+               uart->filemode |= SERIAL_MODE_OUTPUT_TRIGGERED;
+       else
+               uart->filemode &= ~SERIAL_MODE_OUTPUT_TRIGGERED;
+       spin_unlock_irqrestore(&uart->open_lock, flags);
+       if (up)
+               snd_uart16550_output_write(substream);
+}
+
+static struct snd_rawmidi_ops snd_uart16550_output =
+{
+       .open =         snd_uart16550_output_open,
+       .close =        snd_uart16550_output_close,
+       .trigger =      snd_uart16550_output_trigger,
+};
+
+static struct snd_rawmidi_ops snd_uart16550_input =
+{
+       .open =         snd_uart16550_input_open,
+       .close =        snd_uart16550_input_close,
+       .trigger =      snd_uart16550_input_trigger,
+};
+
+static int snd_uart16550_free(struct snd_uart16550 *uart)
+{
+       if (uart->irq >= 0)
+               free_irq(uart->irq, uart);
+       release_and_free_resource(uart->res_base);
+       kfree(uart);
+       return 0;
+};
+
+static int snd_uart16550_dev_free(struct snd_device *device)
+{
+       struct snd_uart16550 *uart = device->device_data;
+       return snd_uart16550_free(uart);
+}
+
+static int snd_uart16550_create(struct snd_card *card,
+                               unsigned long iobase,
+                               int irq,
+                               unsigned int speed,
+                               unsigned int base,
+                               int adaptor,
+                               int droponfull,
+                               struct snd_uart16550 **ruart)
+{
+       static struct snd_device_ops ops = {
+               .dev_free =     snd_uart16550_dev_free,
+       };
+       struct snd_uart16550 *uart;
+       int err;
+
+
+       if ((uart = kzalloc(sizeof(*uart), GFP_KERNEL)) == NULL)
+               return -ENOMEM;
+       uart->adaptor = adaptor;
+       uart->card = card;
+       spin_lock_init(&uart->open_lock);
+       uart->irq = -1;
+       uart->base = iobase;
+       uart->drop_on_full = droponfull;
+
+       if ((err = snd_uart16550_detect(uart)) <= 0) {
+               printk(KERN_ERR "no UART detected at 0x%lx\n", iobase);
+               snd_uart16550_free(uart);
+               return -ENODEV;
+       }
+
+       if (irq >= 0 && irq != SNDRV_AUTO_IRQ) {
+               if (request_irq(irq, snd_uart16550_interrupt,
+                               0, "Serial MIDI", uart)) {
+                       snd_printk(KERN_WARNING
+                                  "irq %d busy. Using Polling.\n", irq);
+               } else {
+                       uart->irq = irq;
+               }
+       }
+       uart->divisor = base / speed;
+       uart->speed = base / (unsigned int)uart->divisor;
+       uart->speed_base = base;
+       uart->prev_out = -1;
+       uart->prev_in = 0;
+       uart->rstatus = 0;
+       memset(uart->prev_status, 0x80, sizeof(unsigned char) * SNDRV_SERIAL_MAX_OUTS);
+       setup_timer(&uart->buffer_timer, snd_uart16550_buffer_timer,
+                   (unsigned long)uart);
+       uart->timer_running = 0;
+
+       /* Register device */
+       if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, uart, &ops)) < 0) {
+               snd_uart16550_free(uart);
+               return err;
+       }
+
+       switch (uart->adaptor) {
+       case SNDRV_SERIAL_MS124W_SA:
+       case SNDRV_SERIAL_MS124W_MB:
+               /* MS-124W can draw power from RTS and DTR if they
+                  are in opposite states. */ 
+               outb(UART_MCR_RTS | (0&UART_MCR_DTR), uart->base + UART_MCR);
+               break;
+       case SNDRV_SERIAL_MS124T:
+               /* MS-124T can draw power from RTS and/or DTR (preferably
+                  both) if they are asserted. */
+               outb(UART_MCR_RTS | UART_MCR_DTR, uart->base + UART_MCR);
+               break;
+       default:
+               break;
+       }
+
+       if (ruart)
+               *ruart = uart;
+
+       return 0;
+}
+
+static void snd_uart16550_substreams(struct snd_rawmidi_str *stream)
+{
+       struct snd_rawmidi_substream *substream;
+
+       list_for_each_entry(substream, &stream->substreams, list) {
+               sprintf(substream->name, "Serial MIDI %d", substream->number + 1);
+       }
+}
+
+static int snd_uart16550_rmidi(struct snd_uart16550 *uart, int device,
+                              int outs, int ins,
+                              struct snd_rawmidi **rmidi)
+{
+       struct snd_rawmidi *rrawmidi;
+       int err;
+
+       err = snd_rawmidi_new(uart->card, "UART Serial MIDI", device,
+                             outs, ins, &rrawmidi);
+       if (err < 0)
+               return err;
+       snd_rawmidi_set_ops(rrawmidi, SNDRV_RAWMIDI_STREAM_INPUT,
+                           &snd_uart16550_input);
+       snd_rawmidi_set_ops(rrawmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
+                           &snd_uart16550_output);
+       strcpy(rrawmidi->name, "Serial MIDI");
+       snd_uart16550_substreams(&rrawmidi->streams[SNDRV_RAWMIDI_STREAM_OUTPUT]);
+       snd_uart16550_substreams(&rrawmidi->streams[SNDRV_RAWMIDI_STREAM_INPUT]);
+       rrawmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT |
+                              SNDRV_RAWMIDI_INFO_INPUT |
+                              SNDRV_RAWMIDI_INFO_DUPLEX;
+       rrawmidi->private_data = uart;
+       if (rmidi)
+               *rmidi = rrawmidi;
+       return 0;
+}
+
+static int snd_serial_probe(struct platform_device *devptr)
+{
+       struct snd_card *card;
+       struct snd_uart16550 *uart;
+       int err;
+       int dev = devptr->id;
+
+       switch (adaptor[dev]) {
+       case SNDRV_SERIAL_SOUNDCANVAS:
+               ins[dev] = 1;
+               break;
+       case SNDRV_SERIAL_MS124T:
+       case SNDRV_SERIAL_MS124W_SA:
+               outs[dev] = 1;
+               ins[dev] = 1;
+               break;
+       case SNDRV_SERIAL_MS124W_MB:
+               outs[dev] = 16;
+               ins[dev] = 1;
+               break;
+       case SNDRV_SERIAL_GENERIC:
+               break;
+       default:
+               snd_printk(KERN_ERR
+                          "Adaptor type is out of range 0-%d (%d)\n",
+                          SNDRV_SERIAL_MAX_ADAPTOR, adaptor[dev]);
+               return -ENODEV;
+       }
+
+       if (outs[dev] < 1 || outs[dev] > SNDRV_SERIAL_MAX_OUTS) {
+               snd_printk(KERN_ERR
+                          "Count of outputs is out of range 1-%d (%d)\n",
+                          SNDRV_SERIAL_MAX_OUTS, outs[dev]);
+               return -ENODEV;
+       }
+
+       if (ins[dev] < 1 || ins[dev] > SNDRV_SERIAL_MAX_INS) {
+               snd_printk(KERN_ERR
+                          "Count of inputs is out of range 1-%d (%d)\n",
+                          SNDRV_SERIAL_MAX_INS, ins[dev]);
+               return -ENODEV;
+       }
+
+       err  = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
+                           0, &card);
+       if (err < 0)
+               return err;
+
+       strcpy(card->driver, "Serial");
+       strcpy(card->shortname, "Serial MIDI (UART16550A)");
+
+       if ((err = snd_uart16550_create(card,
+                                       port[dev],
+                                       irq[dev],
+                                       speed[dev],
+                                       base[dev],
+                                       adaptor[dev],
+                                       droponfull[dev],
+                                       &uart)) < 0)
+               goto _err;
+
+       err = snd_uart16550_rmidi(uart, 0, outs[dev], ins[dev], &uart->rmidi);
+       if (err < 0)
+               goto _err;
+
+       sprintf(card->longname, "%s [%s] at %#lx, irq %d",
+               card->shortname,
+               adaptor_names[uart->adaptor],
+               uart->base,
+               uart->irq);
+
+       if ((err = snd_card_register(card)) < 0)
+               goto _err;
+
+       platform_set_drvdata(devptr, card);
+       return 0;
+
+ _err:
+       snd_card_free(card);
+       return err;
+}
+
+static int snd_serial_remove(struct platform_device *devptr)
+{
+       snd_card_free(platform_get_drvdata(devptr));
+       return 0;
+}
+
+#define SND_SERIAL_DRIVER      "snd_serial_u16550"
+
+static struct platform_driver snd_serial_driver = {
+       .probe          = snd_serial_probe,
+       .remove         =  snd_serial_remove,
+       .driver         = {
+               .name   = SND_SERIAL_DRIVER,
+       },
+};
+
+static void snd_serial_unregister_all(void)
+{
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(devices); ++i)
+               platform_device_unregister(devices[i]);
+       platform_driver_unregister(&snd_serial_driver);
+}
+
+static int __init alsa_card_serial_init(void)
+{
+       int i, cards, err;
+
+       if ((err = platform_driver_register(&snd_serial_driver)) < 0)
+               return err;
+
+       cards = 0;
+       for (i = 0; i < SNDRV_CARDS; i++) {
+               struct platform_device *device;
+               if (! enable[i])
+                       continue;
+               device = platform_device_register_simple(SND_SERIAL_DRIVER,
+                                                        i, NULL, 0);
+               if (IS_ERR(device))
+                       continue;
+               if (!platform_get_drvdata(device)) {
+                       platform_device_unregister(device);
+                       continue;
+               }
+               devices[i] = device;
+               cards++;
+       }
+       if (! cards) {
+#ifdef MODULE
+               printk(KERN_ERR "serial midi soundcard not found or device busy\n");
+#endif
+               snd_serial_unregister_all();
+               return -ENODEV;
+       }
+       return 0;
+}
+
+static void __exit alsa_card_serial_exit(void)
+{
+       snd_serial_unregister_all();
+}
+
+module_init(alsa_card_serial_init)
+module_exit(alsa_card_serial_exit)