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0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  *   serial.c
0004  *   Copyright (c) by Jaroslav Kysela <perex@perex.cz>,
0005  *                    Isaku Yamahata <yamahata@private.email.ne.jp>,
0006  *            George Hansper <ghansper@apana.org.au>,
0007  *            Hannu Savolainen
0008  *
0009  *   This code is based on the code from ALSA 0.5.9, but heavily rewritten.
0010  *
0011  * Sat Mar 31 17:27:57 PST 2001 tim.mann@compaq.com 
0012  *      Added support for the Midiator MS-124T and for the MS-124W in
0013  *      Single Addressed (S/A) or Multiple Burst (M/B) mode, with
0014  *      power derived either parasitically from the serial port or
0015  *      from a separate power supply.
0016  *
0017  *      More documentation can be found in serial-u16550.txt.
0018  */
0019 
0020 #include <linux/init.h>
0021 #include <linux/interrupt.h>
0022 #include <linux/err.h>
0023 #include <linux/platform_device.h>
0024 #include <linux/slab.h>
0025 #include <linux/ioport.h>
0026 #include <linux/module.h>
0027 #include <linux/io.h>
0028 #include <sound/core.h>
0029 #include <sound/rawmidi.h>
0030 #include <sound/initval.h>
0031 
0032 #include <linux/serial_reg.h>
0033 #include <linux/jiffies.h>
0034 
0035 MODULE_DESCRIPTION("MIDI serial u16550");
0036 MODULE_LICENSE("GPL");
0037 
0038 #define SNDRV_SERIAL_SOUNDCANVAS 0 /* Roland Soundcanvas; F5 NN selects part */
0039 #define SNDRV_SERIAL_MS124T 1      /* Midiator MS-124T */
0040 #define SNDRV_SERIAL_MS124W_SA 2   /* Midiator MS-124W in S/A mode */
0041 #define SNDRV_SERIAL_MS124W_MB 3   /* Midiator MS-124W in M/B mode */
0042 #define SNDRV_SERIAL_GENERIC 4     /* Generic Interface */
0043 #define SNDRV_SERIAL_MAX_ADAPTOR SNDRV_SERIAL_GENERIC
0044 static const char * const adaptor_names[] = {
0045     "Soundcanvas",
0046         "MS-124T",
0047     "MS-124W S/A",
0048     "MS-124W M/B",
0049     "Generic"
0050 };
0051 
0052 #define SNDRV_SERIAL_NORMALBUFF 0 /* Normal blocking buffer operation */
0053 #define SNDRV_SERIAL_DROPBUFF   1 /* Non-blocking discard operation */
0054 
0055 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;  /* Index 0-MAX */
0056 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;   /* ID for this card */
0057 static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE; /* Enable this card */
0058 static long port[SNDRV_CARDS] = SNDRV_DEFAULT_PORT; /* 0x3f8,0x2f8,0x3e8,0x2e8 */
0059 static int irq[SNDRV_CARDS] = SNDRV_DEFAULT_IRQ;    /* 3,4,5,7,9,10,11,14,15 */
0060 static int speed[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 38400}; /* 9600,19200,38400,57600,115200 */
0061 static int base[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 115200}; /* baud base */
0062 static int outs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};  /* 1 to 16 */
0063 static int ins[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};  /* 1 to 16 */
0064 static int adaptor[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = SNDRV_SERIAL_SOUNDCANVAS};
0065 static bool droponfull[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS -1)] = SNDRV_SERIAL_NORMALBUFF };
0066 
0067 module_param_array(index, int, NULL, 0444);
0068 MODULE_PARM_DESC(index, "Index value for Serial MIDI.");
0069 module_param_array(id, charp, NULL, 0444);
0070 MODULE_PARM_DESC(id, "ID string for Serial MIDI.");
0071 module_param_array(enable, bool, NULL, 0444);
0072 MODULE_PARM_DESC(enable, "Enable UART16550A chip.");
0073 module_param_hw_array(port, long, ioport, NULL, 0444);
0074 MODULE_PARM_DESC(port, "Port # for UART16550A chip.");
0075 module_param_hw_array(irq, int, irq, NULL, 0444);
0076 MODULE_PARM_DESC(irq, "IRQ # for UART16550A chip.");
0077 module_param_array(speed, int, NULL, 0444);
0078 MODULE_PARM_DESC(speed, "Speed in bauds.");
0079 module_param_array(base, int, NULL, 0444);
0080 MODULE_PARM_DESC(base, "Base for divisor in bauds.");
0081 module_param_array(outs, int, NULL, 0444);
0082 MODULE_PARM_DESC(outs, "Number of MIDI outputs.");
0083 module_param_array(ins, int, NULL, 0444);
0084 MODULE_PARM_DESC(ins, "Number of MIDI inputs.");
0085 module_param_array(droponfull, bool, NULL, 0444);
0086 MODULE_PARM_DESC(droponfull, "Flag to enable drop-on-full buffer mode");
0087 
0088 module_param_array(adaptor, int, NULL, 0444);
0089 MODULE_PARM_DESC(adaptor, "Type of adaptor.");
0090 
0091 /*#define SNDRV_SERIAL_MS124W_MB_NOCOMBO 1*/  /* Address outs as 0-3 instead of bitmap */
0092 
0093 #define SNDRV_SERIAL_MAX_OUTS   16      /* max 64, min 16 */
0094 #define SNDRV_SERIAL_MAX_INS    16      /* max 64, min 16 */
0095 
0096 #define TX_BUFF_SIZE        (1<<15)     /* Must be 2^n */
0097 #define TX_BUFF_MASK        (TX_BUFF_SIZE - 1)
0098 
0099 #define SERIAL_MODE_NOT_OPENED      (0)
0100 #define SERIAL_MODE_INPUT_OPEN      (1 << 0)
0101 #define SERIAL_MODE_OUTPUT_OPEN     (1 << 1)
0102 #define SERIAL_MODE_INPUT_TRIGGERED (1 << 2)
0103 #define SERIAL_MODE_OUTPUT_TRIGGERED    (1 << 3)
0104 
0105 struct snd_uart16550 {
0106     struct snd_card *card;
0107     struct snd_rawmidi *rmidi;
0108     struct snd_rawmidi_substream *midi_output[SNDRV_SERIAL_MAX_OUTS];
0109     struct snd_rawmidi_substream *midi_input[SNDRV_SERIAL_MAX_INS];
0110 
0111     int filemode;       /* open status of file */
0112 
0113     spinlock_t open_lock;
0114 
0115     int irq;
0116 
0117     unsigned long base;
0118 
0119     unsigned int speed;
0120     unsigned int speed_base;
0121     unsigned char divisor;
0122 
0123     unsigned char old_divisor_lsb;
0124     unsigned char old_divisor_msb;
0125     unsigned char old_line_ctrl_reg;
0126 
0127     /* parameter for using of write loop */
0128     short int fifo_limit;   /* used in uart16550 */
0129         short int fifo_count;   /* used in uart16550 */
0130 
0131     /* type of adaptor */
0132     int adaptor;
0133 
0134     /* inputs */
0135     int prev_in;
0136     unsigned char rstatus;
0137 
0138     /* outputs */
0139     int prev_out;
0140     unsigned char prev_status[SNDRV_SERIAL_MAX_OUTS];
0141 
0142     /* write buffer and its writing/reading position */
0143     unsigned char tx_buff[TX_BUFF_SIZE];
0144     int buff_in_count;
0145         int buff_in;
0146         int buff_out;
0147         int drop_on_full;
0148 
0149     /* wait timer */
0150     unsigned int timer_running:1;
0151     struct timer_list buffer_timer;
0152 
0153 };
0154 
0155 static struct platform_device *devices[SNDRV_CARDS];
0156 
0157 static inline void snd_uart16550_add_timer(struct snd_uart16550 *uart)
0158 {
0159     if (!uart->timer_running) {
0160         /* timer 38600bps * 10bit * 16byte */
0161         mod_timer(&uart->buffer_timer, jiffies + (HZ + 255) / 256);
0162         uart->timer_running = 1;
0163     }
0164 }
0165 
0166 static inline void snd_uart16550_del_timer(struct snd_uart16550 *uart)
0167 {
0168     if (uart->timer_running) {
0169         del_timer(&uart->buffer_timer);
0170         uart->timer_running = 0;
0171     }
0172 }
0173 
0174 /* This macro is only used in snd_uart16550_io_loop */
0175 static inline void snd_uart16550_buffer_output(struct snd_uart16550 *uart)
0176 {
0177     unsigned short buff_out = uart->buff_out;
0178     if (uart->buff_in_count > 0) {
0179         outb(uart->tx_buff[buff_out], uart->base + UART_TX);
0180         uart->fifo_count++;
0181         buff_out++;
0182         buff_out &= TX_BUFF_MASK;
0183         uart->buff_out = buff_out;
0184         uart->buff_in_count--;
0185     }
0186 }
0187 
0188 /* This loop should be called with interrupts disabled
0189  * We don't want to interrupt this, 
0190  * as we're already handling an interrupt 
0191  */
0192 static void snd_uart16550_io_loop(struct snd_uart16550 * uart)
0193 {
0194     unsigned char c, status;
0195     int substream;
0196 
0197     /* recall previous stream */
0198     substream = uart->prev_in;
0199 
0200     /* Read Loop */
0201     while ((status = inb(uart->base + UART_LSR)) & UART_LSR_DR) {
0202         /* while receive data ready */
0203         c = inb(uart->base + UART_RX);
0204 
0205         /* keep track of last status byte */
0206         if (c & 0x80)
0207             uart->rstatus = c;
0208 
0209         /* handle stream switch */
0210         if (uart->adaptor == SNDRV_SERIAL_GENERIC) {
0211             if (uart->rstatus == 0xf5) {
0212                 if (c <= SNDRV_SERIAL_MAX_INS && c > 0)
0213                     substream = c - 1;
0214                 if (c != 0xf5)
0215                     /* prevent future bytes from being
0216                        interpreted as streams */
0217                     uart->rstatus = 0;
0218             } else if ((uart->filemode & SERIAL_MODE_INPUT_OPEN)
0219                    && uart->midi_input[substream])
0220                 snd_rawmidi_receive(uart->midi_input[substream],
0221                             &c, 1);
0222         } else if ((uart->filemode & SERIAL_MODE_INPUT_OPEN) &&
0223                uart->midi_input[substream])
0224             snd_rawmidi_receive(uart->midi_input[substream], &c, 1);
0225 
0226         if (status & UART_LSR_OE)
0227             snd_printk(KERN_WARNING
0228                    "%s: Overrun on device at 0x%lx\n",
0229                    uart->rmidi->name, uart->base);
0230     }
0231 
0232     /* remember the last stream */
0233     uart->prev_in = substream;
0234 
0235     /* no need of check SERIAL_MODE_OUTPUT_OPEN because if not,
0236        buffer is never filled. */
0237     /* Check write status */
0238     if (status & UART_LSR_THRE)
0239         uart->fifo_count = 0;
0240     if (uart->adaptor == SNDRV_SERIAL_MS124W_SA
0241        || uart->adaptor == SNDRV_SERIAL_GENERIC) {
0242         /* Can't use FIFO, must send only when CTS is true */
0243         status = inb(uart->base + UART_MSR);
0244         while (uart->fifo_count == 0 && (status & UART_MSR_CTS) &&
0245                uart->buff_in_count > 0) {
0246                snd_uart16550_buffer_output(uart);
0247                status = inb(uart->base + UART_MSR);
0248         }
0249     } else {
0250         /* Write loop */
0251         while (uart->fifo_count < uart->fifo_limit /* Can we write ? */
0252                && uart->buff_in_count > 0)  /* Do we want to? */
0253             snd_uart16550_buffer_output(uart);
0254     }
0255     if (uart->irq < 0 && uart->buff_in_count > 0)
0256         snd_uart16550_add_timer(uart);
0257 }
0258 
0259 /* NOTES ON SERVICING INTERUPTS
0260  * ---------------------------
0261  * After receiving a interrupt, it is important to indicate to the UART that
0262  * this has been done. 
0263  * For a Rx interrupt, this is done by reading the received byte.
0264  * For a Tx interrupt this is done by either:
0265  * a) Writing a byte
0266  * b) Reading the IIR
0267  * It is particularly important to read the IIR if a Tx interrupt is received
0268  * when there is no data in tx_buff[], as in this case there no other
0269  * indication that the interrupt has been serviced, and it remains outstanding
0270  * indefinitely. This has the curious side effect that and no further interrupts
0271  * will be generated from this device AT ALL!!.
0272  * It is also desirable to clear outstanding interrupts when the device is
0273  * opened/closed.
0274  *
0275  *
0276  * Note that some devices need OUT2 to be set before they will generate
0277  * interrupts at all. (Possibly tied to an internal pull-up on CTS?)
0278  */
0279 static irqreturn_t snd_uart16550_interrupt(int irq, void *dev_id)
0280 {
0281     struct snd_uart16550 *uart;
0282 
0283     uart = dev_id;
0284     spin_lock(&uart->open_lock);
0285     if (uart->filemode == SERIAL_MODE_NOT_OPENED) {
0286         spin_unlock(&uart->open_lock);
0287         return IRQ_NONE;
0288     }
0289     /* indicate to the UART that the interrupt has been serviced */
0290     inb(uart->base + UART_IIR);
0291     snd_uart16550_io_loop(uart);
0292     spin_unlock(&uart->open_lock);
0293     return IRQ_HANDLED;
0294 }
0295 
0296 /* When the polling mode, this function calls snd_uart16550_io_loop. */
0297 static void snd_uart16550_buffer_timer(struct timer_list *t)
0298 {
0299     unsigned long flags;
0300     struct snd_uart16550 *uart;
0301 
0302     uart = from_timer(uart, t, buffer_timer);
0303     spin_lock_irqsave(&uart->open_lock, flags);
0304     snd_uart16550_del_timer(uart);
0305     snd_uart16550_io_loop(uart);
0306     spin_unlock_irqrestore(&uart->open_lock, flags);
0307 }
0308 
0309 /*
0310  *  this method probes, if an uart sits on given port
0311  *  return 0 if found
0312  *  return negative error if not found
0313  */
0314 static int snd_uart16550_detect(struct snd_uart16550 *uart)
0315 {
0316     unsigned long io_base = uart->base;
0317     int ok;
0318     unsigned char c;
0319 
0320     /* Do some vague tests for the presence of the uart */
0321     if (io_base == 0 || io_base == SNDRV_AUTO_PORT) {
0322         return -ENODEV; /* Not configured */
0323     }
0324 
0325     if (!devm_request_region(uart->card->dev, io_base, 8, "Serial MIDI")) {
0326         snd_printk(KERN_ERR "u16550: can't grab port 0x%lx\n", io_base);
0327         return -EBUSY;
0328     }
0329 
0330     /* uart detected unless one of the following tests should fail */
0331     ok = 1;
0332     /* 8 data-bits, 1 stop-bit, parity off, DLAB = 0 */
0333     outb(UART_LCR_WLEN8, io_base + UART_LCR); /* Line Control Register */
0334     c = inb(io_base + UART_IER);
0335     /* The top four bits of the IER should always == 0 */
0336     if ((c & 0xf0) != 0)
0337         ok = 0;     /* failed */
0338 
0339     outb(0xaa, io_base + UART_SCR);
0340     /* Write arbitrary data into the scratch reg */
0341     c = inb(io_base + UART_SCR);
0342     /* If it comes back, it's OK */
0343     if (c != 0xaa)
0344         ok = 0;     /* failed */
0345 
0346     outb(0x55, io_base + UART_SCR);
0347     /* Write arbitrary data into the scratch reg */
0348     c = inb(io_base + UART_SCR);
0349     /* If it comes back, it's OK */
0350     if (c != 0x55)
0351         ok = 0;     /* failed */
0352 
0353     return ok;
0354 }
0355 
0356 static void snd_uart16550_do_open(struct snd_uart16550 * uart)
0357 {
0358     char byte;
0359 
0360     /* Initialize basic variables */
0361     uart->buff_in_count = 0;
0362     uart->buff_in = 0;
0363     uart->buff_out = 0;
0364     uart->fifo_limit = 1;
0365     uart->fifo_count = 0;
0366     uart->timer_running = 0;
0367 
0368     outb(UART_FCR_ENABLE_FIFO   /* Enable FIFO's (if available) */
0369          | UART_FCR_CLEAR_RCVR  /* Clear receiver FIFO */
0370          | UART_FCR_CLEAR_XMIT  /* Clear transmitter FIFO */
0371          | UART_FCR_TRIGGER_4   /* Set FIFO trigger at 4-bytes */
0372     /* NOTE: interrupt generated after T=(time)4-bytes
0373      * if less than UART_FCR_TRIGGER bytes received
0374      */
0375          ,uart->base + UART_FCR);   /* FIFO Control Register */
0376 
0377     if ((inb(uart->base + UART_IIR) & 0xf0) == 0xc0)
0378         uart->fifo_limit = 16;
0379     if (uart->divisor != 0) {
0380         uart->old_line_ctrl_reg = inb(uart->base + UART_LCR);
0381         outb(UART_LCR_DLAB  /* Divisor latch access bit */
0382              ,uart->base + UART_LCR);   /* Line Control Register */
0383         uart->old_divisor_lsb = inb(uart->base + UART_DLL);
0384         uart->old_divisor_msb = inb(uart->base + UART_DLM);
0385 
0386         outb(uart->divisor
0387              ,uart->base + UART_DLL);   /* Divisor Latch Low */
0388         outb(0
0389              ,uart->base + UART_DLM);   /* Divisor Latch High */
0390         /* DLAB is reset to 0 in next outb() */
0391     }
0392     /* Set serial parameters (parity off, etc) */
0393     outb(UART_LCR_WLEN8 /* 8 data-bits */
0394          | 0        /* 1 stop-bit */
0395          | 0        /* parity off */
0396          | 0        /* DLAB = 0 */
0397          ,uart->base + UART_LCR);   /* Line Control Register */
0398 
0399     switch (uart->adaptor) {
0400     default:
0401         outb(UART_MCR_RTS   /* Set Request-To-Send line active */
0402              | UART_MCR_DTR /* Set Data-Terminal-Ready line active */
0403              | UART_MCR_OUT2    /* Set OUT2 - not always required, but when
0404                      * it is, it is ESSENTIAL for enabling interrupts
0405                  */
0406              ,uart->base + UART_MCR);   /* Modem Control Register */
0407         break;
0408     case SNDRV_SERIAL_MS124W_SA:
0409     case SNDRV_SERIAL_MS124W_MB:
0410         /* MS-124W can draw power from RTS and DTR if they
0411            are in opposite states. */ 
0412         outb(UART_MCR_RTS | (0&UART_MCR_DTR) | UART_MCR_OUT2,
0413              uart->base + UART_MCR);
0414         break;
0415     case SNDRV_SERIAL_MS124T:
0416         /* MS-124T can draw power from RTS and/or DTR (preferably
0417            both) if they are both asserted. */
0418         outb(UART_MCR_RTS | UART_MCR_DTR | UART_MCR_OUT2,
0419              uart->base + UART_MCR);
0420         break;
0421     }
0422 
0423     if (uart->irq < 0) {
0424         byte = (0 & UART_IER_RDI)   /* Disable Receiver data interrupt */
0425             |(0 & UART_IER_THRI)    /* Disable Transmitter holding register empty interrupt */
0426             ;
0427     } else if (uart->adaptor == SNDRV_SERIAL_MS124W_SA) {
0428         byte = UART_IER_RDI /* Enable Receiver data interrupt */
0429             | UART_IER_MSI  /* Enable Modem status interrupt */
0430             ;
0431     } else if (uart->adaptor == SNDRV_SERIAL_GENERIC) {
0432         byte = UART_IER_RDI /* Enable Receiver data interrupt */
0433             | UART_IER_MSI  /* Enable Modem status interrupt */
0434             | UART_IER_THRI /* Enable Transmitter holding register empty interrupt */
0435             ;
0436     } else {
0437         byte = UART_IER_RDI /* Enable Receiver data interrupt */
0438             | UART_IER_THRI /* Enable Transmitter holding register empty interrupt */
0439             ;
0440     }
0441     outb(byte, uart->base + UART_IER);  /* Interrupt enable Register */
0442 
0443     inb(uart->base + UART_LSR); /* Clear any pre-existing overrun indication */
0444     inb(uart->base + UART_IIR); /* Clear any pre-existing transmit interrupt */
0445     inb(uart->base + UART_RX);  /* Clear any pre-existing receive interrupt */
0446 }
0447 
0448 static void snd_uart16550_do_close(struct snd_uart16550 * uart)
0449 {
0450     if (uart->irq < 0)
0451         snd_uart16550_del_timer(uart);
0452 
0453     /* NOTE: may need to disable interrupts before de-registering out handler.
0454      * For now, the consequences are harmless.
0455      */
0456 
0457     outb((0 & UART_IER_RDI)     /* Disable Receiver data interrupt */
0458          |(0 & UART_IER_THRI)   /* Disable Transmitter holding register empty interrupt */
0459          ,uart->base + UART_IER);   /* Interrupt enable Register */
0460 
0461     switch (uart->adaptor) {
0462     default:
0463         outb((0 & UART_MCR_RTS)     /* Deactivate Request-To-Send line  */
0464              |(0 & UART_MCR_DTR)    /* Deactivate Data-Terminal-Ready line */
0465              |(0 & UART_MCR_OUT2)   /* Deactivate OUT2 */
0466              ,uart->base + UART_MCR);   /* Modem Control Register */
0467       break;
0468     case SNDRV_SERIAL_MS124W_SA:
0469     case SNDRV_SERIAL_MS124W_MB:
0470         /* MS-124W can draw power from RTS and DTR if they
0471            are in opposite states; leave it powered. */ 
0472         outb(UART_MCR_RTS | (0&UART_MCR_DTR) | (0&UART_MCR_OUT2),
0473              uart->base + UART_MCR);
0474         break;
0475     case SNDRV_SERIAL_MS124T:
0476         /* MS-124T can draw power from RTS and/or DTR (preferably
0477            both) if they are both asserted; leave it powered. */
0478         outb(UART_MCR_RTS | UART_MCR_DTR | (0&UART_MCR_OUT2),
0479              uart->base + UART_MCR);
0480         break;
0481     }
0482 
0483     inb(uart->base + UART_IIR); /* Clear any outstanding interrupts */
0484 
0485     /* Restore old divisor */
0486     if (uart->divisor != 0) {
0487         outb(UART_LCR_DLAB      /* Divisor latch access bit */
0488              ,uart->base + UART_LCR);   /* Line Control Register */
0489         outb(uart->old_divisor_lsb
0490              ,uart->base + UART_DLL);   /* Divisor Latch Low */
0491         outb(uart->old_divisor_msb
0492              ,uart->base + UART_DLM);   /* Divisor Latch High */
0493         /* Restore old LCR (data bits, stop bits, parity, DLAB) */
0494         outb(uart->old_line_ctrl_reg
0495              ,uart->base + UART_LCR);   /* Line Control Register */
0496     }
0497 }
0498 
0499 static int snd_uart16550_input_open(struct snd_rawmidi_substream *substream)
0500 {
0501     unsigned long flags;
0502     struct snd_uart16550 *uart = substream->rmidi->private_data;
0503 
0504     spin_lock_irqsave(&uart->open_lock, flags);
0505     if (uart->filemode == SERIAL_MODE_NOT_OPENED)
0506         snd_uart16550_do_open(uart);
0507     uart->filemode |= SERIAL_MODE_INPUT_OPEN;
0508     uart->midi_input[substream->number] = substream;
0509     spin_unlock_irqrestore(&uart->open_lock, flags);
0510     return 0;
0511 }
0512 
0513 static int snd_uart16550_input_close(struct snd_rawmidi_substream *substream)
0514 {
0515     unsigned long flags;
0516     struct snd_uart16550 *uart = substream->rmidi->private_data;
0517 
0518     spin_lock_irqsave(&uart->open_lock, flags);
0519     uart->filemode &= ~SERIAL_MODE_INPUT_OPEN;
0520     uart->midi_input[substream->number] = NULL;
0521     if (uart->filemode == SERIAL_MODE_NOT_OPENED)
0522         snd_uart16550_do_close(uart);
0523     spin_unlock_irqrestore(&uart->open_lock, flags);
0524     return 0;
0525 }
0526 
0527 static void snd_uart16550_input_trigger(struct snd_rawmidi_substream *substream,
0528                     int up)
0529 {
0530     unsigned long flags;
0531     struct snd_uart16550 *uart = substream->rmidi->private_data;
0532 
0533     spin_lock_irqsave(&uart->open_lock, flags);
0534     if (up)
0535         uart->filemode |= SERIAL_MODE_INPUT_TRIGGERED;
0536     else
0537         uart->filemode &= ~SERIAL_MODE_INPUT_TRIGGERED;
0538     spin_unlock_irqrestore(&uart->open_lock, flags);
0539 }
0540 
0541 static int snd_uart16550_output_open(struct snd_rawmidi_substream *substream)
0542 {
0543     unsigned long flags;
0544     struct snd_uart16550 *uart = substream->rmidi->private_data;
0545 
0546     spin_lock_irqsave(&uart->open_lock, flags);
0547     if (uart->filemode == SERIAL_MODE_NOT_OPENED)
0548         snd_uart16550_do_open(uart);
0549     uart->filemode |= SERIAL_MODE_OUTPUT_OPEN;
0550     uart->midi_output[substream->number] = substream;
0551     spin_unlock_irqrestore(&uart->open_lock, flags);
0552     return 0;
0553 };
0554 
0555 static int snd_uart16550_output_close(struct snd_rawmidi_substream *substream)
0556 {
0557     unsigned long flags;
0558     struct snd_uart16550 *uart = substream->rmidi->private_data;
0559 
0560     spin_lock_irqsave(&uart->open_lock, flags);
0561     uart->filemode &= ~SERIAL_MODE_OUTPUT_OPEN;
0562     uart->midi_output[substream->number] = NULL;
0563     if (uart->filemode == SERIAL_MODE_NOT_OPENED)
0564         snd_uart16550_do_close(uart);
0565     spin_unlock_irqrestore(&uart->open_lock, flags);
0566     return 0;
0567 };
0568 
0569 static inline int snd_uart16550_buffer_can_write(struct snd_uart16550 *uart,
0570                          int Num)
0571 {
0572     if (uart->buff_in_count + Num < TX_BUFF_SIZE)
0573         return 1;
0574     else
0575         return 0;
0576 }
0577 
0578 static inline int snd_uart16550_write_buffer(struct snd_uart16550 *uart,
0579                          unsigned char byte)
0580 {
0581     unsigned short buff_in = uart->buff_in;
0582     if (uart->buff_in_count < TX_BUFF_SIZE) {
0583         uart->tx_buff[buff_in] = byte;
0584         buff_in++;
0585         buff_in &= TX_BUFF_MASK;
0586         uart->buff_in = buff_in;
0587         uart->buff_in_count++;
0588         if (uart->irq < 0) /* polling mode */
0589             snd_uart16550_add_timer(uart);
0590         return 1;
0591     } else
0592         return 0;
0593 }
0594 
0595 static int snd_uart16550_output_byte(struct snd_uart16550 *uart,
0596                      struct snd_rawmidi_substream *substream,
0597                      unsigned char midi_byte)
0598 {
0599     if (uart->buff_in_count == 0                    /* Buffer empty? */
0600         && ((uart->adaptor != SNDRV_SERIAL_MS124W_SA &&
0601         uart->adaptor != SNDRV_SERIAL_GENERIC) ||
0602         (uart->fifo_count == 0                  /* FIFO empty? */
0603          && (inb(uart->base + UART_MSR) & UART_MSR_CTS)))) { /* CTS? */
0604 
0605             /* Tx Buffer Empty - try to write immediately */
0606         if ((inb(uart->base + UART_LSR) & UART_LSR_THRE) != 0) {
0607                 /* Transmitter holding register (and Tx FIFO) empty */
0608                 uart->fifo_count = 1;
0609             outb(midi_byte, uart->base + UART_TX);
0610         } else {
0611                 if (uart->fifo_count < uart->fifo_limit) {
0612                     uart->fifo_count++;
0613                 outb(midi_byte, uart->base + UART_TX);
0614             } else {
0615                     /* Cannot write (buffer empty) -
0616                  * put char in buffer */
0617                 snd_uart16550_write_buffer(uart, midi_byte);
0618             }
0619         }
0620     } else {
0621         if (!snd_uart16550_write_buffer(uart, midi_byte)) {
0622             snd_printk(KERN_WARNING
0623                    "%s: Buffer overrun on device at 0x%lx\n",
0624                    uart->rmidi->name, uart->base);
0625             return 0;
0626         }
0627     }
0628 
0629     return 1;
0630 }
0631 
0632 static void snd_uart16550_output_write(struct snd_rawmidi_substream *substream)
0633 {
0634     unsigned long flags;
0635     unsigned char midi_byte, addr_byte;
0636     struct snd_uart16550 *uart = substream->rmidi->private_data;
0637     char first;
0638     static unsigned long lasttime = 0;
0639     
0640     /* Interrupts are disabled during the updating of the tx_buff,
0641      * since it is 'bad' to have two processes updating the same
0642      * variables (ie buff_in & buff_out)
0643      */
0644 
0645     spin_lock_irqsave(&uart->open_lock, flags);
0646 
0647     if (uart->irq < 0)  /* polling */
0648         snd_uart16550_io_loop(uart);
0649 
0650     if (uart->adaptor == SNDRV_SERIAL_MS124W_MB) {
0651         while (1) {
0652             /* buffer full? */
0653             /* in this mode we need two bytes of space */
0654             if (uart->buff_in_count > TX_BUFF_SIZE - 2)
0655                 break;
0656             if (snd_rawmidi_transmit(substream, &midi_byte, 1) != 1)
0657                 break;
0658 #ifdef SNDRV_SERIAL_MS124W_MB_NOCOMBO
0659             /* select exactly one of the four ports */
0660             addr_byte = (1 << (substream->number + 4)) | 0x08;
0661 #else
0662             /* select any combination of the four ports */
0663             addr_byte = (substream->number << 4) | 0x08;
0664             /* ...except none */
0665             if (addr_byte == 0x08)
0666                 addr_byte = 0xf8;
0667 #endif
0668             snd_uart16550_output_byte(uart, substream, addr_byte);
0669             /* send midi byte */
0670             snd_uart16550_output_byte(uart, substream, midi_byte);
0671         }
0672     } else {
0673         first = 0;
0674         while (snd_rawmidi_transmit_peek(substream, &midi_byte, 1) == 1) {
0675             /* Also send F5 after 3 seconds with no data
0676              * to handle device disconnect */
0677             if (first == 0 &&
0678                 (uart->adaptor == SNDRV_SERIAL_SOUNDCANVAS ||
0679                  uart->adaptor == SNDRV_SERIAL_GENERIC) &&
0680                 (uart->prev_out != substream->number ||
0681                  time_after(jiffies, lasttime + 3*HZ))) {
0682 
0683                 if (snd_uart16550_buffer_can_write(uart, 3)) {
0684                     /* Roland Soundcanvas part selection */
0685                     /* If this substream of the data is
0686                      * different previous substream
0687                      * in this uart, send the change part
0688                      * event
0689                      */
0690                     uart->prev_out = substream->number;
0691                     /* change part */
0692                     snd_uart16550_output_byte(uart, substream,
0693                                   0xf5);
0694                     /* data */
0695                     snd_uart16550_output_byte(uart, substream,
0696                                   uart->prev_out + 1);
0697                     /* If midi_byte is a data byte,
0698                      * send the previous status byte */
0699                     if (midi_byte < 0x80 &&
0700                         uart->adaptor == SNDRV_SERIAL_SOUNDCANVAS)
0701                         snd_uart16550_output_byte(uart, substream, uart->prev_status[uart->prev_out]);
0702                 } else if (!uart->drop_on_full)
0703                     break;
0704 
0705             }
0706 
0707             /* send midi byte */
0708             if (!snd_uart16550_output_byte(uart, substream, midi_byte) &&
0709                 !uart->drop_on_full )
0710                 break;
0711 
0712             if (midi_byte >= 0x80 && midi_byte < 0xf0)
0713                 uart->prev_status[uart->prev_out] = midi_byte;
0714             first = 1;
0715 
0716             snd_rawmidi_transmit_ack( substream, 1 );
0717         }
0718         lasttime = jiffies;
0719     }
0720     spin_unlock_irqrestore(&uart->open_lock, flags);
0721 }
0722 
0723 static void snd_uart16550_output_trigger(struct snd_rawmidi_substream *substream,
0724                      int up)
0725 {
0726     unsigned long flags;
0727     struct snd_uart16550 *uart = substream->rmidi->private_data;
0728 
0729     spin_lock_irqsave(&uart->open_lock, flags);
0730     if (up)
0731         uart->filemode |= SERIAL_MODE_OUTPUT_TRIGGERED;
0732     else
0733         uart->filemode &= ~SERIAL_MODE_OUTPUT_TRIGGERED;
0734     spin_unlock_irqrestore(&uart->open_lock, flags);
0735     if (up)
0736         snd_uart16550_output_write(substream);
0737 }
0738 
0739 static const struct snd_rawmidi_ops snd_uart16550_output =
0740 {
0741     .open =     snd_uart16550_output_open,
0742     .close =    snd_uart16550_output_close,
0743     .trigger =  snd_uart16550_output_trigger,
0744 };
0745 
0746 static const struct snd_rawmidi_ops snd_uart16550_input =
0747 {
0748     .open =     snd_uart16550_input_open,
0749     .close =    snd_uart16550_input_close,
0750     .trigger =  snd_uart16550_input_trigger,
0751 };
0752 
0753 static int snd_uart16550_create(struct snd_card *card,
0754                 unsigned long iobase,
0755                 int irq,
0756                 unsigned int speed,
0757                 unsigned int base,
0758                 int adaptor,
0759                 int droponfull,
0760                 struct snd_uart16550 **ruart)
0761 {
0762     struct snd_uart16550 *uart;
0763     int err;
0764 
0765 
0766     uart = devm_kzalloc(card->dev, sizeof(*uart), GFP_KERNEL);
0767     if (!uart)
0768         return -ENOMEM;
0769     uart->adaptor = adaptor;
0770     uart->card = card;
0771     spin_lock_init(&uart->open_lock);
0772     uart->irq = -1;
0773     uart->base = iobase;
0774     uart->drop_on_full = droponfull;
0775 
0776     err = snd_uart16550_detect(uart);
0777     if (err <= 0) {
0778         printk(KERN_ERR "no UART detected at 0x%lx\n", iobase);
0779         return -ENODEV;
0780     }
0781 
0782     if (irq >= 0 && irq != SNDRV_AUTO_IRQ) {
0783         if (devm_request_irq(card->dev, irq, snd_uart16550_interrupt,
0784                      0, "Serial MIDI", uart)) {
0785             snd_printk(KERN_WARNING
0786                    "irq %d busy. Using Polling.\n", irq);
0787         } else {
0788             uart->irq = irq;
0789         }
0790     }
0791     uart->divisor = base / speed;
0792     uart->speed = base / (unsigned int)uart->divisor;
0793     uart->speed_base = base;
0794     uart->prev_out = -1;
0795     uart->prev_in = 0;
0796     uart->rstatus = 0;
0797     memset(uart->prev_status, 0x80, sizeof(unsigned char) * SNDRV_SERIAL_MAX_OUTS);
0798     timer_setup(&uart->buffer_timer, snd_uart16550_buffer_timer, 0);
0799     uart->timer_running = 0;
0800 
0801     switch (uart->adaptor) {
0802     case SNDRV_SERIAL_MS124W_SA:
0803     case SNDRV_SERIAL_MS124W_MB:
0804         /* MS-124W can draw power from RTS and DTR if they
0805            are in opposite states. */ 
0806         outb(UART_MCR_RTS | (0&UART_MCR_DTR), uart->base + UART_MCR);
0807         break;
0808     case SNDRV_SERIAL_MS124T:
0809         /* MS-124T can draw power from RTS and/or DTR (preferably
0810            both) if they are asserted. */
0811         outb(UART_MCR_RTS | UART_MCR_DTR, uart->base + UART_MCR);
0812         break;
0813     default:
0814         break;
0815     }
0816 
0817     if (ruart)
0818         *ruart = uart;
0819 
0820     return 0;
0821 }
0822 
0823 static void snd_uart16550_substreams(struct snd_rawmidi_str *stream)
0824 {
0825     struct snd_rawmidi_substream *substream;
0826 
0827     list_for_each_entry(substream, &stream->substreams, list) {
0828         sprintf(substream->name, "Serial MIDI %d", substream->number + 1);
0829     }
0830 }
0831 
0832 static int snd_uart16550_rmidi(struct snd_uart16550 *uart, int device,
0833                    int outs, int ins,
0834                    struct snd_rawmidi **rmidi)
0835 {
0836     struct snd_rawmidi *rrawmidi;
0837     int err;
0838 
0839     err = snd_rawmidi_new(uart->card, "UART Serial MIDI", device,
0840                   outs, ins, &rrawmidi);
0841     if (err < 0)
0842         return err;
0843     snd_rawmidi_set_ops(rrawmidi, SNDRV_RAWMIDI_STREAM_INPUT,
0844                 &snd_uart16550_input);
0845     snd_rawmidi_set_ops(rrawmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
0846                 &snd_uart16550_output);
0847     strcpy(rrawmidi->name, "Serial MIDI");
0848     snd_uart16550_substreams(&rrawmidi->streams[SNDRV_RAWMIDI_STREAM_OUTPUT]);
0849     snd_uart16550_substreams(&rrawmidi->streams[SNDRV_RAWMIDI_STREAM_INPUT]);
0850     rrawmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT |
0851                    SNDRV_RAWMIDI_INFO_INPUT |
0852                    SNDRV_RAWMIDI_INFO_DUPLEX;
0853     rrawmidi->private_data = uart;
0854     if (rmidi)
0855         *rmidi = rrawmidi;
0856     return 0;
0857 }
0858 
0859 static int snd_serial_probe(struct platform_device *devptr)
0860 {
0861     struct snd_card *card;
0862     struct snd_uart16550 *uart;
0863     int err;
0864     int dev = devptr->id;
0865 
0866     switch (adaptor[dev]) {
0867     case SNDRV_SERIAL_SOUNDCANVAS:
0868         ins[dev] = 1;
0869         break;
0870     case SNDRV_SERIAL_MS124T:
0871     case SNDRV_SERIAL_MS124W_SA:
0872         outs[dev] = 1;
0873         ins[dev] = 1;
0874         break;
0875     case SNDRV_SERIAL_MS124W_MB:
0876         outs[dev] = 16;
0877         ins[dev] = 1;
0878         break;
0879     case SNDRV_SERIAL_GENERIC:
0880         break;
0881     default:
0882         snd_printk(KERN_ERR
0883                "Adaptor type is out of range 0-%d (%d)\n",
0884                SNDRV_SERIAL_MAX_ADAPTOR, adaptor[dev]);
0885         return -ENODEV;
0886     }
0887 
0888     if (outs[dev] < 1 || outs[dev] > SNDRV_SERIAL_MAX_OUTS) {
0889         snd_printk(KERN_ERR
0890                "Count of outputs is out of range 1-%d (%d)\n",
0891                SNDRV_SERIAL_MAX_OUTS, outs[dev]);
0892         return -ENODEV;
0893     }
0894 
0895     if (ins[dev] < 1 || ins[dev] > SNDRV_SERIAL_MAX_INS) {
0896         snd_printk(KERN_ERR
0897                "Count of inputs is out of range 1-%d (%d)\n",
0898                SNDRV_SERIAL_MAX_INS, ins[dev]);
0899         return -ENODEV;
0900     }
0901 
0902     err  = snd_devm_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
0903                  0, &card);
0904     if (err < 0)
0905         return err;
0906 
0907     strcpy(card->driver, "Serial");
0908     strcpy(card->shortname, "Serial MIDI (UART16550A)");
0909 
0910     err = snd_uart16550_create(card, port[dev], irq[dev], speed[dev],
0911                    base[dev], adaptor[dev], droponfull[dev],
0912                    &uart);
0913     if (err < 0)
0914         return err;
0915 
0916     err = snd_uart16550_rmidi(uart, 0, outs[dev], ins[dev], &uart->rmidi);
0917     if (err < 0)
0918         return err;
0919 
0920     sprintf(card->longname, "%s [%s] at %#lx, irq %d",
0921         card->shortname,
0922         adaptor_names[uart->adaptor],
0923         uart->base,
0924         uart->irq);
0925 
0926     err = snd_card_register(card);
0927     if (err < 0)
0928         return err;
0929 
0930     platform_set_drvdata(devptr, card);
0931     return 0;
0932 }
0933 
0934 #define SND_SERIAL_DRIVER   "snd_serial_u16550"
0935 
0936 static struct platform_driver snd_serial_driver = {
0937     .probe      = snd_serial_probe,
0938     .driver     = {
0939         .name   = SND_SERIAL_DRIVER,
0940     },
0941 };
0942 
0943 static void snd_serial_unregister_all(void)
0944 {
0945     int i;
0946 
0947     for (i = 0; i < ARRAY_SIZE(devices); ++i)
0948         platform_device_unregister(devices[i]);
0949     platform_driver_unregister(&snd_serial_driver);
0950 }
0951 
0952 static int __init alsa_card_serial_init(void)
0953 {
0954     int i, cards, err;
0955 
0956     err = platform_driver_register(&snd_serial_driver);
0957     if (err < 0)
0958         return err;
0959 
0960     cards = 0;
0961     for (i = 0; i < SNDRV_CARDS; i++) {
0962         struct platform_device *device;
0963         if (! enable[i])
0964             continue;
0965         device = platform_device_register_simple(SND_SERIAL_DRIVER,
0966                              i, NULL, 0);
0967         if (IS_ERR(device))
0968             continue;
0969         if (!platform_get_drvdata(device)) {
0970             platform_device_unregister(device);
0971             continue;
0972         }
0973         devices[i] = device;
0974         cards++;
0975     }
0976     if (! cards) {
0977 #ifdef MODULE
0978         printk(KERN_ERR "serial midi soundcard not found or device busy\n");
0979 #endif
0980         snd_serial_unregister_all();
0981         return -ENODEV;
0982     }
0983     return 0;
0984 }
0985 
0986 static void __exit alsa_card_serial_exit(void)
0987 {
0988     snd_serial_unregister_all();
0989 }
0990 
0991 module_init(alsa_card_serial_init)
0992 module_exit(alsa_card_serial_exit)
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