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author | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2014-10-07 08:29:16 +0200 |
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committer | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2014-10-07 16:35:20 +0200 |
commit | 6ec438e8a323cf623cdaecce6f2b3b52b062881a (patch) | |
tree | 8cd71b9fb974897a825b36ea1f070dd4405af46f /c/src/libchip/serial/ns16550-context.c | |
parent | bsps: Add Termios console driver initialization (diff) | |
download | rtems-6ec438e8a323cf623cdaecce6f2b3b52b062881a.tar.bz2 |
libchip/serial: Add alternative NS16550 driver
Use the Termios device API.
Diffstat (limited to 'c/src/libchip/serial/ns16550-context.c')
-rw-r--r-- | c/src/libchip/serial/ns16550-context.c | 677 |
1 files changed, 677 insertions, 0 deletions
diff --git a/c/src/libchip/serial/ns16550-context.c b/c/src/libchip/serial/ns16550-context.c new file mode 100644 index 0000000000..a812271037 --- /dev/null +++ b/c/src/libchip/serial/ns16550-context.c @@ -0,0 +1,677 @@ +/** + * @file + * + * This file contains the TTY driver for the National Semiconductor NS16550. + * + * This part is widely cloned and second sourced. It is found in a number + * of "Super IO" controllers. + * + * This driver uses the termios pseudo driver. + */ + +/* + * COPYRIGHT (c) 1998 by Radstone Technology + * + * THIS FILE IS PROVIDED TO YOU, THE USER, "AS IS", WITHOUT WARRANTY OF ANY + * KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK + * AS TO THE QUALITY AND PERFORMANCE OF ALL CODE IN THIS FILE IS WITH YOU. + * + * You are hereby granted permission to use, copy, modify, and distribute + * this file, provided that this notice, plus the above copyright notice + * and disclaimer, appears in all copies. Radstone Technology will provide + * no support for this code. + * + * COPYRIGHT (c) 1989-2012. + * On-Line Applications Research Corporation (OAR). + * + * 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. + */ + +#include <stdlib.h> + +#include <rtems/bspIo.h> + +#include <bsp.h> + +#include "ns16550.h" +#include "ns16550_p.h" + +#if defined(BSP_FEATURE_IRQ_EXTENSION) + #include <bsp/irq.h> +#elif defined(BSP_FEATURE_IRQ_LEGACY) + #include <bsp/irq.h> +#elif defined(__PPC__) || defined(__i386__) + #include <bsp/irq.h> + #define BSP_FEATURE_IRQ_LEGACY + #ifdef BSP_SHARED_HANDLER_SUPPORT + #define BSP_FEATURE_IRQ_LEGACY_SHARED_HANDLER_SUPPORT + #endif +#endif + +static uint32_t NS16550_GetBaudDivisor(ns16550_context *ctx, uint32_t baud) +{ + uint32_t clock = ctx->clock; + uint32_t baudDivisor = (clock != 0 ? clock : 115200) / (baud * 16); + + if (ctx->has_fractional_divider_register) { + uint32_t fractionalDivider = 0x10; + uint32_t err = baud; + uint32_t mulVal; + uint32_t divAddVal; + + clock /= 16 * baudDivisor; + for (mulVal = 1; mulVal < 16; ++mulVal) { + for (divAddVal = 0; divAddVal < mulVal; ++divAddVal) { + uint32_t actual = (mulVal * clock) / (mulVal + divAddVal); + uint32_t newErr = actual > baud ? actual - baud : baud - actual; + + if (newErr < err) { + err = newErr; + fractionalDivider = (mulVal << 4) | divAddVal; + } + } + } + + (*ctx->set_reg)( + ctx->port, + NS16550_FRACTIONAL_DIVIDER, + fractionalDivider + ); + } + + return baudDivisor; +} + +/* + * ns16550_enable_interrupts + * + * This routine initializes the port to have the specified interrupts masked. + */ +static void ns16550_enable_interrupts( + ns16550_context *ctx, + int mask +) +{ + (*ctx->set_reg)(ctx->port, NS16550_INTERRUPT_ENABLE, mask); +} + +/* + * ns16550_probe + */ + +bool ns16550_probe(rtems_termios_device_context *base) +{ + ns16550_context *ctx = (ns16550_context *) base; + uintptr_t pNS16550; + uint8_t ucDataByte; + uint32_t ulBaudDivisor; + ns16550_set_reg setReg; + ns16550_get_reg getReg; + + ctx->modem_control = SP_MODEM_IRQ; + + pNS16550 = ctx->port; + setReg = ctx->set_reg; + getReg = ctx->get_reg; + + /* Clear the divisor latch, clear all interrupt enables, + * and reset and + * disable the FIFO's. + */ + + (*setReg)(pNS16550, NS16550_LINE_CONTROL, 0x0); + ns16550_enable_interrupts(ctx, NS16550_DISABLE_ALL_INTR ); + + /* Set the divisor latch and set the baud rate. */ + + ulBaudDivisor = NS16550_GetBaudDivisor(ctx, ctx->initial_baud); + ucDataByte = SP_LINE_DLAB; + (*setReg)(pNS16550, NS16550_LINE_CONTROL, ucDataByte); + + /* XXX */ + (*setReg)(pNS16550,NS16550_TRANSMIT_BUFFER,(uint8_t)(ulBaudDivisor & 0xffU)); + (*setReg)( + pNS16550,NS16550_INTERRUPT_ENABLE, + (uint8_t)(( ulBaudDivisor >> 8 ) & 0xffU ) + ); + + /* Clear the divisor latch and set the character size to eight bits */ + /* with one stop bit and no parity checking. */ + ucDataByte = EIGHT_BITS; + (*setReg)(pNS16550, NS16550_LINE_CONTROL, ucDataByte); + + /* Enable and reset transmit and receive FIFOs. TJA */ + ucDataByte = SP_FIFO_ENABLE; + (*setReg)(pNS16550, NS16550_FIFO_CONTROL, ucDataByte); + + ucDataByte = SP_FIFO_ENABLE | SP_FIFO_RXRST | SP_FIFO_TXRST; + (*setReg)(pNS16550, NS16550_FIFO_CONTROL, ucDataByte); + + ns16550_enable_interrupts(ctx, NS16550_DISABLE_ALL_INTR); + + /* Set data terminal ready. */ + /* And open interrupt tristate line */ + (*setReg)(pNS16550, NS16550_MODEM_CONTROL,ctx->modem_control); + + (*getReg)(pNS16550, NS16550_LINE_STATUS ); + (*getReg)(pNS16550, NS16550_RECEIVE_BUFFER ); + + return true; +} + +#if defined(BSP_FEATURE_IRQ_EXTENSION) || defined(BSP_FEATURE_IRQ_LEGACY) + +/** + * @brief Process interrupt. + */ +static void ns16550_isr(void *arg) +{ + rtems_termios_tty *tty = arg; + ns16550_context *ctx = rtems_termios_get_device_context(tty); + uint32_t port = ctx->port; + ns16550_get_reg get = ctx->get_reg; + int i = 0; + char buf [SP_FIFO_SIZE]; + + /* Iterate until no more interrupts are pending */ + do { + /* Fetch received characters */ + for (i = 0; i < SP_FIFO_SIZE; ++i) { + if ((get( port, NS16550_LINE_STATUS) & SP_LSR_RDY) != 0) { + buf [i] = (char) get(port, NS16550_RECEIVE_BUFFER); + } else { + break; + } + } + + /* Enqueue fetched characters */ + rtems_termios_enqueue_raw_characters(tty, buf, i); + + /* Check if we can dequeue transmitted characters */ + if (ctx->transmit_fifo_chars > 0 + && (get( port, NS16550_LINE_STATUS) & SP_LSR_THOLD) != 0) { + + /* Dequeue transmitted characters */ + rtems_termios_dequeue_characters( + tty, + ctx->transmit_fifo_chars + ); + } + } while ((get( port, NS16550_INTERRUPT_ID) & SP_IID_0) == 0); +} +#endif + +/* + * ns16550_initialize_interrupts + * + * This routine initializes the port to operate in interrupt driver mode. + */ +static void ns16550_initialize_interrupts( + struct rtems_termios_tty *tty, + ns16550_context *ctx +) +{ + #ifdef BSP_FEATURE_IRQ_EXTENSION + { + rtems_status_code sc = RTEMS_SUCCESSFUL; + sc = rtems_interrupt_handler_install( + ctx->irq, + "NS16550", + RTEMS_INTERRUPT_SHARED, + ns16550_isr, + tty + ); + if (sc != RTEMS_SUCCESSFUL) { + /* FIXME */ + printk( "%s: Error: Install interrupt handler\n", __func__); + rtems_fatal_error_occurred( 0xdeadbeef); + } + } + #elif defined(BSP_FEATURE_IRQ_LEGACY) + { + int rv = 0; + #ifdef BSP_FEATURE_IRQ_LEGACY_SHARED_HANDLER_SUPPORT + rtems_irq_connect_data cd = { + ctx->irq, + ns16550_isr, + tty, + NULL, + NULL, + NULL, + NULL + }; + rv = BSP_install_rtems_shared_irq_handler( &cd); + #else + rtems_irq_connect_data cd = { + ctx->irq, + ns16550_isr, + tty, + NULL, + NULL, + NULL + }; + rv = BSP_install_rtems_irq_handler( &cd); + #endif + if (rv == 0) { + /* FIXME */ + printk( "%s: Error: Install interrupt handler\n", __func__); + rtems_fatal_error_occurred( 0xdeadbeef); + } + } + #endif +} + +/* + * ns16550_open + */ + +static bool ns16550_open( + struct rtems_termios_tty *tty, + rtems_termios_device_context *base, + struct termios *term, + rtems_libio_open_close_args_t *args +) +{ + ns16550_context *ctx = (ns16550_context *) base; + + /* Set initial baud */ + rtems_termios_set_initial_baud(tty, ctx->initial_baud); + + if (tty->handler.mode == TERMIOS_IRQ_DRIVEN) { + ns16550_initialize_interrupts(tty, ctx); + ns16550_enable_interrupts(ctx, NS16550_ENABLE_ALL_INTR_EXCEPT_TX); + } + + return true; +} + +static void ns16550_cleanup_interrupts( + struct rtems_termios_tty *tty, + ns16550_context *ctx +) +{ + #if defined(BSP_FEATURE_IRQ_EXTENSION) + rtems_status_code sc = RTEMS_SUCCESSFUL; + sc = rtems_interrupt_handler_remove( + ctx->irq, + ns16550_isr, + tty + ); + if (sc != RTEMS_SUCCESSFUL) { + /* FIXME */ + printk("%s: Error: Remove interrupt handler\n", __func__); + rtems_fatal_error_occurred(0xdeadbeef); + } + #elif defined(BSP_FEATURE_IRQ_LEGACY) + int rv = 0; + rtems_irq_connect_data cd = { + .name = ctx->irq, + .hdl = ns16550_isr, + .handle = tty + }; + rv = BSP_remove_rtems_irq_handler(&cd); + if (rv == 0) { + /* FIXME */ + printk("%s: Error: Remove interrupt handler\n", __func__); + rtems_fatal_error_occurred(0xdeadbeef); + } + #endif +} + +/* + * ns16550_close + */ + +static void ns16550_close( + struct rtems_termios_tty *tty, + rtems_termios_device_context *base, + rtems_libio_open_close_args_t *args +) +{ + ns16550_context *ctx = (ns16550_context *) base; + + ns16550_enable_interrupts(ctx, NS16550_DISABLE_ALL_INTR); + + if (tty->handler.mode == TERMIOS_IRQ_DRIVEN) { + ns16550_cleanup_interrupts(tty, ctx); + } +} + +/** + * @brief Polled write for NS16550. + */ +void ns16550_polled_putchar(rtems_termios_device_context *base, char out) +{ + ns16550_context *ctx = (ns16550_context *) base; + uintptr_t port = ctx->port; + ns16550_get_reg get = ctx->get_reg; + ns16550_set_reg set = ctx->set_reg; + uint32_t status = 0; + rtems_interrupt_lock_context lock_context; + + /* Save port interrupt mask */ + uint32_t interrupt_mask = get( port, NS16550_INTERRUPT_ENABLE); + + /* Disable port interrupts */ + ns16550_enable_interrupts(ctx, NS16550_DISABLE_ALL_INTR); + + while (true) { + /* Try to transmit the character in a critical section */ + rtems_termios_device_lock_acquire(&ctx->base, &lock_context); + + /* Read the transmitter holding register and check it */ + status = get( port, NS16550_LINE_STATUS); + if ((status & SP_LSR_THOLD) != 0) { + /* Transmit character */ + set( port, NS16550_TRANSMIT_BUFFER, out); + + /* Finished */ + rtems_termios_device_lock_release(&ctx->base, &lock_context); + break; + } else { + rtems_termios_device_lock_release(&ctx->base, &lock_context); + } + + /* Wait for transmitter holding register to be empty */ + do { + status = get( port, NS16550_LINE_STATUS); + } while ((status & SP_LSR_THOLD) == 0); + } + + /* Restore port interrupt mask */ + set( port, NS16550_INTERRUPT_ENABLE, interrupt_mask); +} + +/* + * These routines provide control of the RTS and DTR lines + */ + +/* + * ns16550_assert_RTS + */ + +static void ns16550_assert_RTS(rtems_termios_device_context *base) +{ + ns16550_context *ctx = (ns16550_context *) base; + rtems_interrupt_lock_context lock_context; + + /* + * Assert RTS + */ + rtems_termios_device_lock_acquire(base, &lock_context); + ctx->modem_control |= SP_MODEM_RTS; + (*ctx->set_reg)(ctx->port, NS16550_MODEM_CONTROL, ctx->modem_control); + rtems_termios_device_lock_release(base, &lock_context); +} + +/* + * ns16550_negate_RTS + */ + +static void ns16550_negate_RTS(rtems_termios_device_context *base) +{ + ns16550_context *ctx = (ns16550_context *) base; + rtems_interrupt_lock_context lock_context; + + /* + * Negate RTS + */ + rtems_termios_device_lock_acquire(base, &lock_context); + ctx->modem_control &= ~SP_MODEM_RTS; + (*ctx->set_reg)(ctx->port, NS16550_MODEM_CONTROL, ctx->modem_control); + rtems_termios_device_lock_release(base, &lock_context); +} + +/* + * These flow control routines utilise a connection from the local DTR + * line to the remote CTS line + */ + +/* + * ns16550_assert_DTR + */ + +static void ns16550_assert_DTR(rtems_termios_device_context *base) +{ + ns16550_context *ctx = (ns16550_context *) base; + rtems_interrupt_lock_context lock_context; + + /* + * Assert DTR + */ + rtems_termios_device_lock_acquire(base, &lock_context); + ctx->modem_control |= SP_MODEM_DTR; + (*ctx->set_reg)(ctx->port, NS16550_MODEM_CONTROL, ctx->modem_control); + rtems_termios_device_lock_release(base, &lock_context); +} + +/* + * ns16550_negate_DTR + */ + +static void ns16550_negate_DTR(rtems_termios_device_context *base) +{ + ns16550_context *ctx = (ns16550_context *) base; + rtems_interrupt_lock_context lock_context; + + /* + * Negate DTR + */ + rtems_termios_device_lock_acquire(base, &lock_context); + ctx->modem_control &=~SP_MODEM_DTR; + (*ctx->set_reg)(ctx->port, NS16550_MODEM_CONTROL,ctx->modem_control); + rtems_termios_device_lock_release(base, &lock_context); +} + +/* + * ns16550_set_attributes + * + * This function sets the channel to reflect the requested termios + * port settings. + */ + +static bool ns16550_set_attributes( + rtems_termios_device_context *base, + const struct termios *t +) +{ + ns16550_context *ctx = (ns16550_context *) base; + uint32_t pNS16550; + uint32_t ulBaudDivisor; + uint8_t ucLineControl; + uint32_t baud_requested; + ns16550_set_reg setReg; + rtems_interrupt_lock_context lock_context; + + pNS16550 = ctx->port; + setReg = ctx->set_reg; + + /* + * Calculate the baud rate divisor + */ + + baud_requested = rtems_termios_baud_to_number(t->c_cflag); + ulBaudDivisor = NS16550_GetBaudDivisor(ctx, baud_requested); + + ucLineControl = 0; + + /* + * Parity + */ + + if (t->c_cflag & PARENB) { + ucLineControl |= SP_LINE_PAR; + if (!(t->c_cflag & PARODD)) + ucLineControl |= SP_LINE_ODD; + } + + /* + * Character Size + */ + + if (t->c_cflag & CSIZE) { + switch (t->c_cflag & CSIZE) { + case CS5: ucLineControl |= FIVE_BITS; break; + case CS6: ucLineControl |= SIX_BITS; break; + case CS7: ucLineControl |= SEVEN_BITS; break; + case CS8: ucLineControl |= EIGHT_BITS; break; + } + } else { + ucLineControl |= EIGHT_BITS; /* default to 9600,8,N,1 */ + } + + /* + * Stop Bits + */ + + if (t->c_cflag & CSTOPB) { + ucLineControl |= SP_LINE_STOP; /* 2 stop bits */ + } else { + ; /* 1 stop bit */ + } + + /* + * Now actually set the chip + */ + + rtems_termios_device_lock_acquire(base, &lock_context); + + /* + * Set the baud rate + * + * NOTE: When the Divisor Latch Access Bit (DLAB) is set to 1, + * the transmit buffer and interrupt enable registers + * turn into the LSB and MSB divisor latch registers. + */ + + (*setReg)(pNS16550, NS16550_LINE_CONTROL, SP_LINE_DLAB); + (*setReg)(pNS16550, NS16550_TRANSMIT_BUFFER, ulBaudDivisor&0xff); + (*setReg)(pNS16550, NS16550_INTERRUPT_ENABLE, (ulBaudDivisor>>8)&0xff); + + /* + * Now write the line control + */ + (*setReg)(pNS16550, NS16550_LINE_CONTROL, ucLineControl ); + + rtems_termios_device_lock_release(base, &lock_context); + + return true; +} + +/** + * @brief Transmits up to @a len characters from @a buf. + * + * This routine is invoked either from task context with disabled interrupts to + * start a new transmission process with exactly one character in case of an + * idle output state or from the interrupt handler to refill the transmitter. + * + * Returns always zero. + */ +static void ns16550_write_support_int( + rtems_termios_device_context *base, + const char *buf, + size_t len +) +{ + ns16550_context *ctx = (ns16550_context *) base; + uint32_t port = ctx->port; + ns16550_set_reg set = ctx->set_reg; + int i = 0; + int out = len > SP_FIFO_SIZE ? SP_FIFO_SIZE : len; + + for (i = 0; i < out; ++i) { + set( port, NS16550_TRANSMIT_BUFFER, buf [i]); + } + + ctx->transmit_fifo_chars = out; + + if (out > 0) { + ns16550_enable_interrupts(ctx, NS16550_ENABLE_ALL_INTR); + } else { + ns16550_enable_interrupts(ctx, NS16550_ENABLE_ALL_INTR_EXCEPT_TX); + } +} + +/* + * ns16550_write_support_polled + * + * Console Termios output entry point. + * + */ + +static void ns16550_write_support_polled( + rtems_termios_device_context *base, + const char *buf, + size_t len +) +{ + size_t nwrite = 0; + + /* + * poll each byte in the string out of the port. + */ + while (nwrite < len) { + /* + * transmit character + */ + ns16550_polled_putchar(base, *buf++); + nwrite++; + } +} + +/* + * Debug gets() support + */ +int ns16550_polled_getchar(rtems_termios_device_context *base) +{ + ns16550_context *ctx = (ns16550_context *) base; + uint32_t pNS16550; + unsigned char ucLineStatus; + uint8_t cChar; + ns16550_get_reg getReg; + + pNS16550 = ctx->port; + getReg = ctx->get_reg; + + ucLineStatus = (*getReg)(pNS16550, NS16550_LINE_STATUS); + if (ucLineStatus & SP_LSR_RDY) { + cChar = (*getReg)(pNS16550, NS16550_RECEIVE_BUFFER); + return (int)cChar; + } + return -1; +} + +/* + * Flow control is only supported when using interrupts + */ + +const rtems_termios_device_flow ns16550_flow_rtscts = { + .stop_remote_tx = ns16550_negate_RTS, + .start_remote_tx = ns16550_assert_RTS +}; + +const rtems_termios_device_flow ns16550_flow_dtrcts = { + .stop_remote_tx = ns16550_negate_DTR, + .start_remote_tx = ns16550_assert_DTR +}; + +const rtems_termios_device_handler ns16550_handler_interrupt = { + .first_open = ns16550_open, + .last_close = ns16550_close, + .poll_read = NULL, + .write = ns16550_write_support_int, + .set_attributes = ns16550_set_attributes, + .mode = TERMIOS_IRQ_DRIVEN +}; + +const rtems_termios_device_handler ns16550_handler_polled = { + .first_open = ns16550_open, + .last_close = ns16550_close, + .poll_read = ns16550_polled_getchar, + .write = ns16550_write_support_polled, + .set_attributes = ns16550_set_attributes, + .mode = TERMIOS_POLLED +}; |