/*
* Copyright (c) 2016.
* Chris Johns <chrisj@rtems.org>
*
* This software is Copyright (C) 1998 by T.sqware - all rights limited
* It is provided in to the public domain "as is", can be freely modified
* as far as this copyight notice is kept unchanged, but does not imply
* an endorsement by T.sqware of the product in which it is included.
*/
#include <bsp.h>
#include <bsp/irq-generic.h>
#include <libchip/serial.h>
#include "../../../shared/dev/serial/legacy-console.h"
int putDebugChar(int ch); /* write a single character */
int getDebugChar(void); /* read and return a single char */
/* Check is any characters received are a ^C */
int i386_gdb_uart_ctrl_c_check(void);
/* Raw interrupt handler. */
void i386_gdb_uart_isr(void);
/* assign an exception handler */
void exceptionHandler(int, void (*handler)(void));
/* User supplied remote debug option. */
extern int remote_debug;
/* Current uart and port used by the gdb stub */
static int uart_current;
static int uart_vector;
static console_tbl* port_current;
/*
* Interrupt service routine for all, it does it check whether ^C is received
* if yes it will flip TF bit before returning.
*
* Note: it should be installed as raw interrupt handler.
*
* Warning: I do not like the use of the global data, I am not
* sure if this is SMP safe.
*/
int i386_gdb_uart_isr_regsav[4] RTEMS_UNUSED;
__asm__ (".p2align 4");
__asm__ (".text");
__asm__ (".globl i386_gdb_uart_isr");
__asm__ ("i386_gdb_uart_isr:");
__asm__ (" pusha"); /* Push all */
__asm__ (" call i386_gdb_uart_ctrl_c_check"); /* Look for ^C */
__asm__ (" movl %eax, i386_gdb_uart_isr_regsav"); /* Save eax */
__asm__ (" popa"); /* Pop all */
__asm__ (" xchgl %eax, i386_gdb_uart_isr_regsav"); /* Exchange eax */
__asm__ (" cmpl $0, %eax"); /* 1 == ^C */
__asm__ (" je i386_gdb_uart_isr_1"); /* branch if 0 */
__asm__ (" movl %ebx, i386_gdb_uart_isr_regsav + 4"); /* Save ebx */
__asm__ (" movl %edx, i386_gdb_uart_isr_regsav + 8"); /* Save edx */
__asm__ (" popl %ebx"); /* Pop eip */
__asm__ (" popl %edx"); /* Pop cs */
__asm__ (" popl %eax"); /* Pop flags */
__asm__ (" orl $0x100, %eax"); /* Modify it */
__asm__ (" pushl %eax"); /* Push it back */
__asm__ (" pushl %edx"); /* Push cs */
__asm__ (" pushl %ebx"); /* Push eip */
__asm__ (" movl i386_gdb_uart_isr_regsav + 4, %ebx"); /* Restore ebx */
__asm__ (" movl i386_gdb_uart_isr_regsav + 8, %edx"); /* Restore edx */
__asm__ ("i386_gdb_uart_isr_1:");
__asm__ (" movl i386_gdb_uart_isr_regsav, %eax"); /* Restore eax */
__asm__ (" iret"); /* Done */
static int gdb_hello_index;
static const char *const gdb_hello = "+";
static inline uint8_t BSP_i8259a_irq_in_service_reg(uint32_t ioport)
{
uint8_t isr;
outport_byte(ioport, PIC_OCW3_SEL | PIC_OCW3_RR | PIC_OCW3_RIS);
inport_byte(ioport, isr);
outport_byte(ioport, PIC_OCW3_SEL | PIC_OCW3_RR);
return isr;
}
static inline void BSP_irq_ack_at_i8259a(const int irqLine)
{
uint8_t slave_isr = 0;
if (irqLine >= 8) {
outport_byte(PIC_SLAVE_COMMAND_IO_PORT, PIC_EOI);
slave_isr = BSP_i8259a_irq_in_service_reg(PIC_SLAVE_COMMAND_IO_PORT);
}
/*
* Only issue the EOI to the master if there are no more interrupts in
* service for the slave. i8259a data sheet page 18, The Special Fully Nested
* Mode, b.
*/
if (slave_isr == 0)
outport_byte(PIC_MASTER_COMMAND_IO_PORT, PIC_EOI);
}
int i386_gdb_uart_ctrl_c_check(void)
{
BSP_irq_ack_at_i8259a(uart_vector);
if (port_current) {
int c = 0;
while (c >= 0) {
c = port_current->pDeviceFns->deviceRead(uart_current);
if (c == 3) {
gdb_hello_index = 0;
return 1;
} else if (gdb_hello[gdb_hello_index] == (char) c) {
++gdb_hello_index;
if (gdb_hello[gdb_hello_index] == '\0') {
gdb_hello_index = 0;
return 1;
}
} else {
gdb_hello_index = 0;
}
}
}
return 0;
}
static void
nop(const rtems_raw_irq_connect_data* notused)
{
}
static int
isOn(const rtems_raw_irq_connect_data* notused)
{
return 1;
}
int i386_stub_glue_uart(void)
{
if (port_current == NULL)
return -1;
return uart_current;
}
/*
* Initialize glue code linking i386-stub with the rest of
* the system
*/
void
i386_stub_glue_init(int uart)
{
rtems_device_minor_number minor = (rtems_device_minor_number) uart;
port_current = console_find_console_entry(NULL, 0, &minor);
if (port_current == NULL) {
printk("GDB: invalid minor number for UART\n");
return;
}
uart_current = uart;
/* Intialise the UART, assuming polled drivers */
port_current->pDeviceFns->deviceInitialize(uart);
}
static void BSP_uart_on(const rtems_raw_irq_connect_data* used)
{
bsp_interrupt_vector_enable(used->idtIndex - BSP_IRQ_VECTOR_BASE);
}
static void BSP_uart_off(const rtems_raw_irq_connect_data* used)
{
bsp_interrupt_vector_disable(used->idtIndex - BSP_IRQ_VECTOR_BASE);
}
/*
* In order to have a possibility to break into
* running program, one has to call this function
*/
void i386_stub_glue_init_breakin(void)
{
rtems_raw_irq_connect_data uart_raw_irq_data;
if (port_current == NULL) {
printk("GDB: no port initialised\n");
return;
}
if ((port_current->ulIntVector == 0) || (port_current->ulIntVector > 16)) {
printk("GDB: no UART interrupt support\n");
}
else {
uart_vector = port_current->ulIntVector;
uart_raw_irq_data.idtIndex = port_current->ulIntVector + BSP_IRQ_VECTOR_BASE;
if (!i386_get_current_idt_entry(&uart_raw_irq_data)) {
printk("GBD: cannot get idt entry\n");
rtems_fatal_error_occurred(1);
}
if (!i386_delete_idt_entry(&uart_raw_irq_data)) {
printk("GDB: cannot delete idt entry\n");
rtems_fatal_error_occurred(1);
}
uart_raw_irq_data.on = BSP_uart_on;
uart_raw_irq_data.off = BSP_uart_off;
/* Install ISR */
uart_raw_irq_data.idtIndex = port_current->ulIntVector + BSP_IRQ_VECTOR_BASE;
uart_raw_irq_data.hdl = i386_gdb_uart_isr;
if (!i386_set_idt_entry (&uart_raw_irq_data)) {
printk("GDB: raw exception handler connection failed\n");
rtems_fatal_error_occurred(1);
}
/* Enable interrupts, this is a bit of a hack because we
* have to know the device but there is no other call. */
(*port_current->setRegister)(port_current->ulCtrlPort1, 1, 0x01);
}
}
int
putDebugChar(int ch)
{
if (port_current != NULL) {
port_current->pDeviceFns->deviceWritePolled(uart_current, ch);
}
return 1;
}
int getDebugChar(void)
{
int c = -1;
if (port_current != NULL) {
while (c < 0)
c = port_current->pDeviceFns->deviceRead(uart_current);
}
return c;
}
void exceptionHandler(int vector, void (*handler)(void))
{
rtems_raw_irq_connect_data excep_raw_irq_data;
excep_raw_irq_data.idtIndex = vector;
if(!i386_get_current_idt_entry(&excep_raw_irq_data))
{
printk("GDB: cannot get idt entry\n");
rtems_fatal_error_occurred(1);
}
if(!i386_delete_idt_entry(&excep_raw_irq_data))
{
printk("GDB: cannot delete idt entry\n");
rtems_fatal_error_occurred(1);
}
excep_raw_irq_data.on = nop;
excep_raw_irq_data.off = nop;
excep_raw_irq_data.isOn = isOn;
excep_raw_irq_data.hdl = handler;
if (!i386_set_idt_entry (&excep_raw_irq_data)) {
printk("GDB: raw exception handler connection failed\n");
rtems_fatal_error_occurred(1);
}
return;
}
