source: rtems/bsps/shared/grlib/uart/apbuart_cons.c @ 411c297

/*  This file contains the driver for the GRLIB APBUART serial port. The driver
 *  is implemented by using the cons.c console layer. Interrupt/Polling/Task
 *  driven mode can be configured using driver resources:
 *
 *  - mode   (0=Polling, 1=Interrupt, 2=Task-Driven-Interrupt Mode)
 *  - syscon (0=Force not Ssystem Console, 1=Suggest System Console)
 *
 *  The BSP define APBUART_INFO_AVAIL in order to add the info routine
 *  used for debugging.
 *
 *  COPYRIGHT (c) 2010.
 *  Cobham Gaisler AB.
 *
 *  The license and distribution terms for this file may be
 *  found in the file LICENSE in this distribution or at
 *  http://www.rtems.org/license/LICENSE.
 */

/******************* Driver manager interface ***********************/
#include <bsp.h>
#include <stdlib.h>
#include <assert.h>
#include <rtems/bspIo.h>
#include <string.h>
#include <stdio.h>

#include <drvmgr/drvmgr.h>
#include <grlib/ambapp_bus.h>
#include <grlib/apbuart.h>
#include <grlib/ambapp.h>
#include <grlib/grlib.h>
#include <grlib/cons.h>
#include <rtems/termiostypes.h>
#include <grlib/apbuart_cons.h>

/*#define DEBUG 1  */

#ifdef DEBUG
#define DBG(x...) printk(x)
#else
#define DBG(x...)
#endif

/* LEON3 Low level transmit/receive functions provided by debug-uart code */
#ifdef LEON3
extern struct apbuart_regs *leon3_debug_uart; /* The debug UART */
#endif

/* Probed hardware capabilities */
enum {
        CAP_FIFO = 0x01, /* FIFO available */
        CAP_DI   = 0x02, /* RX delayed interrupt available */
};
struct apbuart_priv {
        struct console_dev condev;
        struct drvmgr_dev *dev;
        struct apbuart_regs *regs;
        struct rtems_termios_tty *tty;
        char devName[32];
        volatile int sending;
        int mode;
        int cap;
};

/* Getters for different interfaces. It happens to be just casting which we do
 * in one place to avoid getting cast away. */
static struct console_dev *base_get_condev(rtems_termios_device_context *base)
{
        return (struct console_dev *) base;
}

static struct apbuart_priv *condev_get_priv(struct console_dev *condev)
{
        return (struct apbuart_priv *) condev;
}

static struct apbuart_priv *base_get_priv(rtems_termios_device_context *base)
{
        return condev_get_priv(base_get_condev(base));
}

/* TERMIOS Layer Callback functions */
static bool first_open(
  rtems_termios_tty *tty,
  rtems_termios_device_context *base,
  struct termios *term,
  rtems_libio_open_close_args_t *args
);
static void last_close(
  rtems_termios_tty *tty,
  rtems_termios_device_context *base,
  rtems_libio_open_close_args_t *args
);
static void write_interrupt(
  rtems_termios_device_context *base,
  const char *buf,
  size_t len
);
static bool set_attributes(
        rtems_termios_device_context *base,
        const struct termios *t
);
static void get_attributes(
        rtems_termios_device_context *base,
        struct termios *t
);
static int read_polled(rtems_termios_device_context *base);
static int read_task(rtems_termios_device_context *base);
static void write_polled(
  rtems_termios_device_context *base,
  const char *buf,
  size_t len
);

static void apbuart_cons_isr(void *arg);
int apbuart_get_baud(struct apbuart_priv *uart);

int apbuart_init1(struct drvmgr_dev *dev);
#ifdef APBUART_INFO_AVAIL
static int apbuart_info(
        struct drvmgr_dev *dev,
        void (*print_line)(void *p, char *str),
        void *p, int, char *argv[]);
#define APBUART_INFO_FUNC apbuart_info
#else
#define APBUART_INFO_FUNC NULL
#endif

struct drvmgr_drv_ops apbuart_ops =
{
        .init = {apbuart_init1, NULL, NULL, NULL},
        .remove = NULL,
        .info = APBUART_INFO_FUNC
};

static struct amba_dev_id apbuart_ids[] =
{
        {VENDOR_GAISLER, GAISLER_APBUART},
        {0, 0}          /* Mark end of table */
};

static struct amba_drv_info apbuart_drv_info =
{
        {
                DRVMGR_OBJ_DRV,                         /* Driver */
                NULL,                                   /* Next driver */
                NULL,                                   /* Device list */
                DRIVER_AMBAPP_GAISLER_APBUART_ID,       /* Driver ID */
                "APBUART_DRV",                          /* Driver Name */
                DRVMGR_BUS_TYPE_AMBAPP,                 /* Bus Type */
                &apbuart_ops,
                NULL,                                   /* Funcs */
                0,                                      /* No devices yet */
                sizeof(struct apbuart_priv),            /*DrvMgr alloc private*/
        },
        &apbuart_ids[0]
};

void apbuart_cons_register_drv (void)
{
        DBG("Registering APBUART Console driver\n");
        drvmgr_drv_register(&apbuart_drv_info.general);
}

static const rtems_termios_device_handler handler_interrupt = {
        .first_open     = first_open,
        .last_close     = last_close,
        .write          = write_interrupt,
        .set_attributes = set_attributes,
        .mode           = TERMIOS_IRQ_DRIVEN
};

static const rtems_termios_device_handler handler_task = {
        .first_open     = first_open,
        .last_close     = last_close,
        .poll_read      = read_task,
        .write          = write_interrupt,
        .set_attributes = set_attributes,
        .mode           = TERMIOS_TASK_DRIVEN
};

static const rtems_termios_device_handler handler_polled = {
        .first_open     = first_open,
        .last_close     = last_close,
        .poll_read      = read_polled,
        .write          = write_polled,
        .set_attributes = set_attributes,
        .mode           = TERMIOS_POLLED
};

/*
 * APBUART hardware instantiation is flexible. Probe features here and driver
 * can select appropriate routines for the hardware. probecap() return value
 * is a CAP_ bitmask.
 */
static int probecap(struct apbuart_regs *regs)
{
        int cap = 0;

        /* Probe FIFO */
        if (regs->ctrl & APBUART_CTRL_FA) {
                cap |= CAP_FIFO;

                /* Probe RX delayed interrupt */
                regs->ctrl |= APBUART_CTRL_DI;
                if (regs->ctrl & APBUART_CTRL_DI) {
                        regs->ctrl &= ~APBUART_CTRL_DI;
                        cap |= CAP_DI;
                }
        }

        return cap;
}

int apbuart_init1(struct drvmgr_dev *dev)
{
        struct apbuart_priv *priv;
        struct amba_dev_info *ambadev;
        struct ambapp_core *pnpinfo;
        union drvmgr_key_value *value;
        char prefix[32];
        unsigned int db;
        static int first_uart = 1;

        /* The default operation in AMP is to use APBUART[0] for CPU[0],
         * APBUART[1] for CPU[1] and so on. The remaining UARTs is not used
         * since we don't know how many CPU-cores there are. Note this only
         * affects the on-chip amba bus (the root bus). The user can override
         * the default resource sharing by defining driver resources for the
         * APBUART devices on each AMP OS instance.
         */
#if defined(RTEMS_MULTIPROCESSING) && defined(LEON3)
        if (drvmgr_on_rootbus(dev) && dev->minor_drv != LEON3_Cpu_Index &&
            drvmgr_keys_get(dev, NULL) != 0) {
                /* User hasn't configured on-chip APBUART, leave it untouched */
                return DRVMGR_EBUSY;
        }
#endif

        DBG("APBUART[%d] on bus %s\n", dev->minor_drv, dev->parent->dev->name);
        /* Private data was allocated and zeroed by driver manager */
        priv = dev->priv;
        if (!priv)
                return DRVMGR_NOMEM;
        priv->dev = dev;

        /* Get device information from AMBA PnP information */
        ambadev = (struct amba_dev_info *)priv->dev->businfo;
        if (ambadev == NULL)
                return -1;
        pnpinfo = &ambadev->info;
        priv->regs = (struct apbuart_regs *)pnpinfo->apb_slv->start;

        /* Clear HW regs, leave baudrate register as it is */
        priv->regs->status = 0;

        /* leave Transmitter/receiver if this is the RTEMS debug UART (assume
         * it has been setup by boot loader).
         */
        db = 0;
#ifdef LEON3
        if (priv->regs == leon3_debug_uart) {
                db = priv->regs->ctrl & (APBUART_CTRL_RE |
                                        APBUART_CTRL_TE |
                                        APBUART_CTRL_PE |
                                        APBUART_CTRL_PS);
        }
#endif
        /* Let UART debug tunnelling be untouched if Flow-control is set.
         *
         * With old APBUARTs debug is enabled by setting LB and FL, since LB or
         * DB are not reset we can not trust them. However since FL is reset we
         * guess that we are debugging if FL is already set, the debugger set
         * either LB or DB depending on UART capabilities.
         */
        if (priv->regs->ctrl & APBUART_CTRL_FL) {
                db |= priv->regs->ctrl & (APBUART_CTRL_DB |
                      APBUART_CTRL_LB | APBUART_CTRL_FL);
        }

        priv->regs->ctrl = db;

        priv->cap = probecap(priv->regs);

        /* The system console and Debug console may depend on this device, so
         * initialize it straight away.
         *
         * We default to have System Console on first APBUART, user may override
         * this behaviour by setting the syscon option to 0.
         */
        if (drvmgr_on_rootbus(dev) && first_uart) {
                priv->condev.flags = CONSOLE_FLAG_SYSCON;
                first_uart = 0;
        } else {
                priv->condev.flags = 0;
        }

        value = drvmgr_dev_key_get(priv->dev, "syscon", DRVMGR_KT_INT);
        if (value) {
                if (value->i)
                        priv->condev.flags |= CONSOLE_FLAG_SYSCON;
                else
                        priv->condev.flags &= ~CONSOLE_FLAG_SYSCON;
        }

        /* Select 0=Polled, 1=IRQ, 2=Task-Driven UART Mode */
        value = drvmgr_dev_key_get(priv->dev, "mode", DRVMGR_KT_INT);
        if (value)
                priv->mode = value->i;
        else
                priv->mode = TERMIOS_POLLED;
        /* TERMIOS device handlers */
        if (priv->mode == TERMIOS_IRQ_DRIVEN) {
                priv->condev.handler = &handler_interrupt;
        } else if (priv->mode == TERMIOS_TASK_DRIVEN) {
                priv->condev.handler = &handler_task;
        } else {
                priv->condev.handler = &handler_polled;
        }

        priv->condev.fsname = NULL;
        /* Get Filesystem name prefix */
        prefix[0] = '\0';
        if (drvmgr_get_dev_prefix(dev, prefix)) {
                /* Got special prefix, this means we have a bus prefix
                 * And we should use our "bus minor"
                 */
                sprintf(priv->devName, "/dev/%sapbuart%d", prefix, dev->minor_bus);
                priv->condev.fsname = priv->devName;
        } else {
                sprintf(priv->devName, "/dev/apbuart%d", dev->minor_drv);
        }

        /* Register it as a console device, the console driver will register
         * a termios device as well
         */
        console_dev_register(&priv->condev);

        return DRVMGR_OK;
}

#ifdef APBUART_INFO_AVAIL
static int apbuart_info(
        struct drvmgr_dev *dev,
        void (*print_line)(void *p, char *str),
        void *p, int argc, char *argv[])
{
        struct apbuart_priv *priv = dev->priv;
        char *str1;
        char buf[64];

        if (dev->priv == NULL)
                return -DRVMGR_EINVAL;

        if (priv->mode == TERMIOS_POLLED)
                str1 = "TERMIOS_POLLED";
        else if (priv->mode == TERMIOS_IRQ_DRIVEN)
                str1 = "TERMIOS_IRQ_DRIVEN";
        else if (priv->mode == TERMIOS_TASK_DRIVEN)
                str1 = "TERMIOS_TASK_DRIVEN";
        else
                str1 = "BAD MODE";

        sprintf(buf, "UART Mode:   %s", str1);
        print_line(p, buf);
        if (priv->condev.fsname) {
                sprintf(buf, "FS Name:     %s", priv->condev.fsname);
                print_line(p, buf);
        }
        sprintf(buf, "STATUS REG:  0x%x", priv->regs->status);
        print_line(p, buf);
        sprintf(buf, "CTRL REG:    0x%x", priv->regs->ctrl);
        print_line(p, buf);
        sprintf(buf, "SCALER REG:  0x%x  baud rate %d",
                                priv->regs->scaler, apbuart_get_baud(priv));
        print_line(p, buf);

        return DRVMGR_OK;
}
#endif

static bool first_open(
        rtems_termios_tty *tty,
        rtems_termios_device_context *base,
        struct termios *term,
        rtems_libio_open_close_args_t *args
)
{
        struct apbuart_priv *uart = base_get_priv(base);

        uart->tty = tty;

        /* Inherit UART hardware parameters from bootloader on system console */
        if (uart->condev.flags & CONSOLE_FLAG_SYSCON_GRANT) {
                get_attributes(base, term);
                term->c_oflag |= ONLCR;
                set_attributes(base, term);
        }

        /* Enable TX/RX */
        uart->regs->ctrl |= APBUART_CTRL_RE | APBUART_CTRL_TE;

        if (uart->mode != TERMIOS_POLLED) {
                int ret;
                uint32_t ctrl;

                /* Register interrupt and enable it */
                ret = drvmgr_interrupt_register(
                        uart->dev, 0, uart->devName, apbuart_cons_isr, tty
                );
                if (ret) {
                        return false;
                }

                uart->sending = 0;

                /* Turn on RX interrupts */
                ctrl = uart->regs->ctrl;
                ctrl |= APBUART_CTRL_RI;
                if (uart->cap & CAP_DI) {
                        /* Use RX FIFO interrupt only if delayed interrupt available. */
                        ctrl |= (APBUART_CTRL_DI | APBUART_CTRL_RF);
                }
                uart->regs->ctrl = ctrl;
        }

        return true;
}

static void last_close(
        rtems_termios_tty *tty,
        rtems_termios_device_context *base,
        rtems_libio_open_close_args_t *args
)
{
        struct apbuart_priv *uart = base_get_priv(base);
        rtems_interrupt_lock_context lock_context;

        if (uart->mode != TERMIOS_POLLED) {
                /* Turn off RX interrupts */
                rtems_termios_device_lock_acquire(base, &lock_context);
                uart->regs->ctrl &=
                        ~(APBUART_CTRL_DI | APBUART_CTRL_RI | APBUART_CTRL_RF);
                rtems_termios_device_lock_release(base, &lock_context);

                /**** Flush device ****/
                while (uart->sending) {
                        /* Wait until all data has been sent */
                }
                while (
                        (uart->regs->ctrl & APBUART_CTRL_TE) &&
                        !(uart->regs->status & APBUART_STATUS_TS)
                ) {
                        /* Wait until all data has left shift register */
                }

                /* Disable and unregister interrupt handler */
                drvmgr_interrupt_unregister(uart->dev, 0, apbuart_cons_isr, tty);
        }

#ifdef LEON3
        /* Disable TX/RX if not used for DEBUG */
        if (uart->regs != leon3_debug_uart)
                uart->regs->ctrl &= ~(APBUART_CTRL_RE | APBUART_CTRL_TE);
#endif
}

static int read_polled(rtems_termios_device_context *base)
{
        struct apbuart_priv *uart = base_get_priv(base);

        return apbuart_inbyte_nonblocking(uart->regs);
}

/* This function is called from TERMIOS rxdaemon task without device lock. */
static int read_task(rtems_termios_device_context *base)
{
        rtems_interrupt_lock_context lock_context;
        struct apbuart_priv *uart = base_get_priv(base);
        struct apbuart_regs *regs = uart->regs;
        int cnt;
        char buf[33];
        struct rtems_termios_tty *tty;
        uint32_t ctrl_add;

        ctrl_add = APBUART_CTRL_RI;
        if (uart->cap & CAP_DI) {
                ctrl_add |= (APBUART_CTRL_DI | APBUART_CTRL_RF);
        }
        tty = uart->tty;
        do {
                cnt = 0;
                while (
                        (regs->status & APBUART_STATUS_DR) &&
                        (cnt < sizeof(buf))
                ) {
                        buf[cnt] = regs->data;
                        cnt++;
                }
                if (0 < cnt) {
                        /* Tell termios layer about new characters */
                        rtems_termios_enqueue_raw_characters(tty, &buf[0], cnt);
                }

                /*
                 * Turn on RX interrupts. A new character in FIFO now may not
                 * cause interrupt so we must check data ready again
                 * afterwards.
                 */
                rtems_termios_device_lock_acquire(base, &lock_context);
                regs->ctrl |= ctrl_add;
                rtems_termios_device_lock_release(base, &lock_context);
        } while (regs->status & APBUART_STATUS_DR);

        return EOF;
}

int apbuart_get_baud(struct apbuart_priv *uart)
{
        unsigned int core_clk_hz;
        unsigned int scaler;

        /* Get current scaler setting */
        scaler = uart->regs->scaler;

        /* Get APBUART core frequency */
        drvmgr_freq_get(uart->dev, DEV_APB_SLV, &core_clk_hz);

        /* Calculate baud rate from generator "scaler" number */
        return core_clk_hz / ((scaler + 1) * 8);
}

static bool set_attributes(
        rtems_termios_device_context *base,
        const struct termios *t
)
{
        unsigned int core_clk_hz;
        unsigned int scaler;
        unsigned int ctrl;
        int baud;
        struct apbuart_priv *uart = base_get_priv(base);
        rtems_interrupt_lock_context lock_context;

        switch(t->c_cflag & CSIZE) {
                default:
                case CS5:
                case CS6:
                case CS7:
                        /* Hardware doesn't support other than CS8 */
                        return false;
                case CS8:
                        break;
        }

        rtems_termios_device_lock_acquire(base, &lock_context);

        /* Read out current value */
        ctrl = uart->regs->ctrl;

        switch(t->c_cflag & (PARENB|PARODD)){
                case (PARENB|PARODD):
                        /* Odd parity */
                        ctrl |= APBUART_CTRL_PE|APBUART_CTRL_PS;
                        break;

                case PARENB:
                        /* Even parity */
                        ctrl &= ~APBUART_CTRL_PS;
                        ctrl |= APBUART_CTRL_PE;
                        break;

                default:
                case 0:
                case PARODD:
                        /* No Parity */
                        ctrl &= ~(APBUART_CTRL_PS|APBUART_CTRL_PE);
        }

        if (!(t->c_cflag & CLOCAL))
                ctrl |= APBUART_CTRL_FL;
        else
                ctrl &= ~APBUART_CTRL_FL;

        /* Update new settings */
        uart->regs->ctrl = ctrl;

        rtems_termios_device_lock_release(base, &lock_context);

        /* Baud rate */
        baud = rtems_termios_baud_to_number(t->c_ospeed);
        if (baud > 0){
                /* Get APBUART core frequency */
                drvmgr_freq_get(uart->dev, DEV_APB_SLV, &core_clk_hz);

                /* Calculate Baud rate generator "scaler" number */
                scaler = (((core_clk_hz*10)/(baud*8))-5)/10;

                /* Set new baud rate by setting scaler */
                uart->regs->scaler = scaler;
        }

        return true;
}

static void get_attributes(
        rtems_termios_device_context *base,
        struct termios *t
)
{
        struct apbuart_priv *uart = base_get_priv(base);
        unsigned int ctrl;

        t->c_cflag = t->c_cflag & ~(CSIZE|PARENB|PARODD|CLOCAL);

        /* Hardware support only CS8 */
        t->c_cflag |= CS8;

        /* Read out current parity */
        ctrl = uart->regs->ctrl;
        if (ctrl & APBUART_CTRL_PE) {
                if (ctrl & APBUART_CTRL_PS)
                        t->c_cflag |= PARENB|PARODD; /* Odd parity */
                else
                        t->c_cflag |= PARENB; /* Even parity */
        }

        if ((ctrl & APBUART_CTRL_FL) == 0)
                t->c_cflag |= CLOCAL;

        rtems_termios_set_best_baud(t, apbuart_get_baud(uart));
}

static void write_polled(
        rtems_termios_device_context *base,
        const char *buf,
        size_t len
)
{
        struct apbuart_priv *uart = base_get_priv(base);
        int nwrite = 0;

        while (nwrite < len) {
                apbuart_outbyte_polled(uart->regs, *buf++, 0, 0);
                nwrite++;
        }
}

static void write_interrupt(
        rtems_termios_device_context *base,
        const char *buf,
        size_t len
)
{
        struct apbuart_priv *uart = base_get_priv(base);
        struct apbuart_regs *regs = uart->regs;
        int sending;
        unsigned int ctrl;

        ctrl = regs->ctrl;

        if (len > 0) {
                /*
                 * sending is used to remember how much we have outstanding so
                 * we can tell termios later.
                 */
                /* Enable TX interrupt (interrupt is edge-triggered) */
                regs->ctrl = ctrl | APBUART_CTRL_TI;

                if (ctrl & APBUART_CTRL_FA) {
                        /* APBUART with FIFO.. Fill as many as FIFO allows */
                        sending = 0;
                        while (
                                ((regs->status & APBUART_STATUS_TF) == 0) &&
                                (sending < len)
                        ) {
                                regs->data = *buf;
                                buf++;
                                sending++;
                        }
                } else {
                        /* start UART TX, this will result in an interrupt when done */
                        regs->data = *buf;

                        sending = 1;
                }
        } else {
                /* No more to send, disable TX interrupts */
                regs->ctrl = ctrl & ~APBUART_CTRL_TI;

                /* Tell close that we sent everything */
                sending = 0;
        }

        uart->sending = sending;
}

/* Handle UART interrupts */
static void apbuart_cons_isr(void *arg)
{
        rtems_termios_tty *tty = arg;
        rtems_termios_device_context *base;
        struct console_dev *condev = rtems_termios_get_device_context(tty);
        struct apbuart_priv *uart = condev_get_priv(condev);
        struct apbuart_regs *regs = uart->regs;
        unsigned int status;
        char buf[33];
        int cnt;

        if (uart->mode == TERMIOS_TASK_DRIVEN) {
                if ((status = regs->status) & APBUART_STATUS_DR) {
                        rtems_interrupt_lock_context lock_context;

                        /* Turn off RX interrupts */
                        base = rtems_termios_get_device_context(tty);
                        rtems_termios_device_lock_acquire(base, &lock_context);
                        regs->ctrl &=
                            ~(APBUART_CTRL_DI | APBUART_CTRL_RI |
                              APBUART_CTRL_RF);
                        rtems_termios_device_lock_release(base, &lock_context);
                        /* Activate termios RX daemon task */
                        rtems_termios_rxirq_occured(tty);
                }
        } else {
                /*
                 * Get all new characters from APBUART RX (FIFO) and store them
                 * on the stack. Then tell termios about the new characters.
                 * Maximum APBUART RX FIFO size is 32 characters.
                 */
                cnt = 0;
                while (
                        ((status=regs->status) & APBUART_STATUS_DR) &&
                        (cnt < sizeof(buf))
                ) {
                        buf[cnt] = regs->data;
                        cnt++;
                }
                if (0 < cnt) {
                        /* Tell termios layer about new characters */
                        rtems_termios_enqueue_raw_characters(tty, &buf[0], cnt);
                }
        }

        if (uart->sending && (status & APBUART_STATUS_TE)) {
                /* Tell close that we sent everything */
                cnt = uart->sending;

                /*
                 * Tell termios how much we have sent. dequeue() may call
                 * write_interrupt() to refill the transmitter.
                 * write_interrupt() will eventually be called with 0 len to
                 * disable TX interrupts.
                 */
                rtems_termios_dequeue_characters(tty, cnt);
        }
}