Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1044 insertions, 0 deletions

diff --git a/sound/drivers/serial-u16550.c b/sound/drivers/serial-u16550.c
new file mode 100644
index 000000000..0a67b8b9f
--- /dev/null
+++ b/sound/drivers/serial-u16550.c
@@ -0,0 +1,1044 @@
+/*
+ *   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_hw_array(port, long, ioport, NULL, 0444);
+MODULE_PARM_DESC(port, "Port # for UART16550A chip.");
+module_param_hw_array(irq, int, irq, 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(struct timer_list *t)
+{
+	unsigned long flags;
+	struct snd_uart16550 *uart;
+
+	uart = from_timer(uart, t, buffer_timer);
+	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 const struct snd_rawmidi_ops snd_uart16550_output =
+{
+	.open =		snd_uart16550_output_open,
+	.close =	snd_uart16550_output_close,
+	.trigger =	snd_uart16550_output_trigger,
+};
+
+static const 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);
+	timer_setup(&uart->buffer_timer, snd_uart16550_buffer_timer, 0);
+	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)