/* dv-m68hc11spi.c -- Simulation of the 68HC11 SPI Copyright (C) 2000 Free Software Foundation, Inc. Written by Stephane Carrez (stcarrez@worldnet.fr) (From a driver model Contributed by Cygnus Solutions.) This file is part of the program GDB, the GNU debugger. 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. */ #include "sim-main.h" #include "hw-main.h" #include "dv-sockser.h" #include "sim-assert.h" /* DEVICE m68hc11spi - m68hc11 SPI interface DESCRIPTION Implements the m68hc11 Synchronous Serial Peripheral Interface described in the m68hc11 user guide (Chapter 8 in pink book). The SPI I/O controller is directly connected to the CPU interrupt. The simulator implements: - SPI clock emulation - Data transfer - Write collision detection PROPERTIES None PORTS reset (input) Reset port. This port is only used to simulate a reset of the SPI I/O controller. It should be connected to the RESET output of the cpu. */ /* port ID's */ enum { RESET_PORT }; static const struct hw_port_descriptor m68hc11spi_ports[] = { { "reset", RESET_PORT, 0, input_port, }, { NULL, }, }; /* SPI */ struct m68hc11spi { /* Information about next character to be transmited. */ unsigned char tx_char; int tx_bit; unsigned char mode; unsigned char rx_char; unsigned char rx_clear_scsr; unsigned char clk_pin; /* SPI clock rate (twice the real clock). */ unsigned int clock; /* Periodic SPI event. */ struct hw_event* spi_event; }; /* Finish off the partially created hw device. Attach our local callbacks. Wire up our port names etc */ static hw_io_read_buffer_method m68hc11spi_io_read_buffer; static hw_io_write_buffer_method m68hc11spi_io_write_buffer; static hw_port_event_method m68hc11spi_port_event; static hw_ioctl_method m68hc11spi_ioctl; #define M6811_SPI_FIRST_REG (M6811_SPCR) #define M6811_SPI_LAST_REG (M6811_SPDR) static void attach_m68hc11spi_regs (struct hw *me, struct m68hc11spi *controller) { hw_attach_address (hw_parent (me), M6811_IO_LEVEL, io_map, M6811_SPI_FIRST_REG, M6811_SPI_LAST_REG - M6811_SPI_FIRST_REG + 1, me); } static void m68hc11spi_finish (struct hw *me) { struct m68hc11spi *controller; controller = HW_ZALLOC (me, struct m68hc11spi); set_hw_data (me, controller); set_hw_io_read_buffer (me, m68hc11spi_io_read_buffer); set_hw_io_write_buffer (me, m68hc11spi_io_write_buffer); set_hw_ports (me, m68hc11spi_ports); set_hw_port_event (me, m68hc11spi_port_event); #ifdef set_hw_ioctl set_hw_ioctl (me, m68hc11spi_ioctl); #else me->to_ioctl = m68hc11spi_ioctl; #endif /* Attach ourself to our parent bus. */ attach_m68hc11spi_regs (me, controller); /* Initialize to reset state. */ controller->spi_event = NULL; controller->rx_clear_scsr = 0; } /* An event arrives on an interrupt port */ static void m68hc11spi_port_event (struct hw *me, int my_port, struct hw *source, int source_port, int level) { SIM_DESC sd; struct m68hc11spi *controller; sim_cpu* cpu; unsigned8 val; controller = hw_data (me); sd = hw_system (me); cpu = STATE_CPU (sd, 0); switch (my_port) { case RESET_PORT: { HW_TRACE ((me, "SPI reset")); /* Reset the state of SPI registers. */ controller->rx_clear_scsr = 0; if (controller->spi_event) { hw_event_queue_deschedule (me, controller->spi_event); controller->spi_event = 0; } val = 0; m68hc11spi_io_write_buffer (me, &val, io_map, (unsigned_word) M6811_SPCR, 1); break; } default: hw_abort (me, "Event on unknown port %d", my_port); break; } } static void set_bit_port (struct hw *me, sim_cpu *cpu, int port, int mask, int value) { /* TODO: Post an event to inform other devices that pin 'port' changes. This has only a sense if we provide some device that is logically connected to these pin ports (SCLK and MOSI) and that handles the SPI protocol. */ if (value) cpu->ios[port] |= mask; else cpu->ios[port] &= ~mask; } /* When a character is sent/received by the SPI, the PD2..PD5 line are driven by the following signals: B7 B6 -----+---------+--------+---/-+------- MOSI | | | | | | MISO +---------+--------+---/-+ ____ ___ CLK _______/ \____/ \__ CPOL=0, CPHA=0 _______ ____ __ \____/ \___/ CPOL=1, CPHA=0 ____ ____ __ __/ \____/ \___/ CPOL=0, CPHA=1 __ ____ ___ \____/ \____/ \__ CPOL=1, CPHA=1 SS ___ ____ \__________________________//___/ MISO = PD2 MOSI = PD3 SCK = PD4 SS = PD5 */ #define SPI_START_BYTE 0 #define SPI_START_BIT 1 #define SPI_MIDDLE_BIT 2 void m68hc11spi_clock (struct hw *me, void *data) { SIM_DESC sd; struct m68hc11spi* controller; sim_cpu *cpu; int check_interrupt = 0; controller = hw_data (me); sd = hw_system (me); cpu = STATE_CPU (sd, 0); /* Cleanup current event. */ if (controller->spi_event) { hw_event_queue_deschedule (me, controller->spi_event); controller->spi_event = 0; } /* Change a bit of data at each two SPI event. */ if (controller->mode == SPI_START_BIT) { /* Reflect the bit value on bit 2 of port D. */ set_bit_port (me, cpu, M6811_PORTD, (1 << 2), (controller->tx_char & (1 << controller->tx_bit))); controller->tx_bit--; controller->mode = SPI_MIDDLE_BIT; } else if (controller->mode == SPI_MIDDLE_BIT) { controller->mode = SPI_START_BIT; } if (controller->mode == SPI_START_BYTE) { /* Start a new SPI transfer. */ /* TBD: clear SS output. */ controller->mode = SPI_START_BIT; controller->tx_bit = 7; set_bit_port (me, cpu, M6811_PORTD, (1 << 4), ~controller->clk_pin); } else { /* Change the SPI clock at each event on bit 4 of port D. */ controller->clk_pin = ~controller->clk_pin; set_bit_port (me, cpu, M6811_PORTD, (1 << 4), controller->clk_pin); } /* Transmit is now complete for this byte. */ if (controller->mode == SPI_START_BIT && controller->tx_bit < 0) { controller->rx_clear_scsr = 0; cpu->ios[M6811_SPSR] |= M6811_SPIF; if (cpu->ios[M6811_SPCR] & M6811_SPIE) check_interrupt = 1; } else { controller->spi_event = hw_event_queue_schedule (me, controller->clock, m68hc11spi_clock, NULL); } if (check_interrupt) interrupts_update_pending (&cpu->cpu_interrupts); } /* Flags of the SPCR register. */ io_reg_desc spcr_desc[] = { { M6811_SPIE, "SPIE ", "Serial Peripheral Interrupt Enable" }, { M6811_SPE, "SPE ", "Serial Peripheral System Enable" }, { M6811_DWOM, "DWOM ", "Port D Wire-OR mode option" }, { M6811_MSTR, "MSTR ", "Master Mode Select" }, { M6811_CPOL, "CPOL ", "Clock Polarity" }, { M6811_CPHA, "CPHA ", "Clock Phase" }, { M6811_SPR1, "SPR1 ", "SPI Clock Rate Select" }, { M6811_SPR0, "SPR0 ", "SPI Clock Rate Select" }, { 0, 0, 0 } }; /* Flags of the SPSR register. */ io_reg_desc spsr_desc[] = { { M6811_SPIF, "SPIF ", "SPI Transfer Complete flag" }, { M6811_WCOL, "WCOL ", "Write Collision" }, { M6811_MODF, "MODF ", "Mode Fault" }, { 0, 0, 0 } }; static void m68hc11spi_info (struct hw *me) { SIM_DESC sd; uint16 base = 0; sim_cpu *cpu; struct m68hc11spi *controller; uint8 val; sd = hw_system (me); cpu = STATE_CPU (sd, 0); controller = hw_data (me); sim_io_printf (sd, "M68HC11 SPI:\n"); base = cpu_get_io_base (cpu); val = cpu->ios[M6811_SPCR]; print_io_byte (sd, "SPCR", spcr_desc, val, base + M6811_SPCR); sim_io_printf (sd, "\n"); val = cpu->ios[M6811_SPSR]; print_io_byte (sd, "SPSR", spsr_desc, val, base + M6811_SPSR); sim_io_printf (sd, "\n"); if (controller->spi_event) { signed64 t; sim_io_printf (sd, " SPI has %d bits to send\n", controller->tx_bit + 1); t = hw_event_remain_time (me, controller->spi_event); sim_io_printf (sd, " SPI operation finished in %ld cycles\n", (long) t); } } static int m68hc11spi_ioctl (struct hw *me, hw_ioctl_request request, va_list ap) { m68hc11spi_info (me); return 0; } /* generic read/write */ static unsigned m68hc11spi_io_read_buffer (struct hw *me, void *dest, int space, unsigned_word base, unsigned nr_bytes) { SIM_DESC sd; struct m68hc11spi *controller; sim_cpu *cpu; unsigned8 val; HW_TRACE ((me, "read 0x%08lx %d", (long) base, (int) nr_bytes)); sd = hw_system (me); cpu = STATE_CPU (sd, 0); controller = hw_data (me); switch (base) { case M6811_SPSR: controller->rx_clear_scsr = cpu->ios[M6811_SCSR] & (M6811_SPIF | M6811_WCOL | M6811_MODF); case M6811_SPCR: val = cpu->ios[base]; break; case M6811_SPDR: if (controller->rx_clear_scsr) { cpu->ios[M6811_SPSR] &= ~controller->rx_clear_scsr; controller->rx_clear_scsr = 0; interrupts_update_pending (&cpu->cpu_interrupts); } val = controller->rx_char; break; default: return 0; } *((unsigned8*) dest) = val; return 1; } static unsigned m68hc11spi_io_write_buffer (struct hw *me, const void *source, int space, unsigned_word base, unsigned nr_bytes) { SIM_DESC sd; struct m68hc11spi *controller; sim_cpu *cpu; unsigned8 val; HW_TRACE ((me, "write 0x%08lx %d", (long) base, (int) nr_bytes)); sd = hw_system (me); cpu = STATE_CPU (sd, 0); controller = hw_data (me); val = *((const unsigned8*) source); switch (base) { case M6811_SPCR: cpu->ios[M6811_SPCR] = val; /* The SPI clock rate is 2, 4, 16, 32 of the internal CPU clock. We have to drive the clock pin and need a 2x faster clock. */ switch (val & (M6811_SPR1 | M6811_SPR0)) { case 0: controller->clock = 1; break; case 1: controller->clock = 2; break; case 2: controller->clock = 8; break; default: controller->clock = 16; break; } /* Set the clock pin. */ if ((val & M6811_CPOL) && (controller->spi_event == 0 || ((val & M6811_CPHA) && controller->mode == 1))) controller->clk_pin = 1; else controller->clk_pin = 0; set_bit_port (me, cpu, M6811_PORTD, (1 << 4), controller->clk_pin); break; /* Can't write to SPSR. */ case M6811_SPSR: break; case M6811_SPDR: if (!(cpu->ios[M6811_SPCR] & M6811_SPE)) { return 0; } if (controller->rx_clear_scsr) { cpu->ios[M6811_SPSR] &= ~controller->rx_clear_scsr; controller->rx_clear_scsr = 0; interrupts_update_pending (&cpu->cpu_interrupts); } /* If transfer is taking place, a write to SPDR generates a collision. */ if (controller->spi_event) { cpu->ios[M6811_SPSR] |= M6811_WCOL; break; } /* Refuse the write if there was no read of SPSR. */ /* ???? TBD. */ /* Prepare to send a byte. */ controller->tx_char = val; controller->mode = SPI_START_BYTE; /* Toggle clock pin internal value when CPHA is 0 so that it will really change in the middle of a bit. */ if (!(cpu->ios[M6811_SPCR] & M6811_CPHA)) controller->clk_pin = ~controller->clk_pin; cpu->ios[M6811_SPDR] = val; /* Activate transmission. */ m68hc11spi_clock (me, NULL); break; default: return 0; } return nr_bytes; } const struct hw_descriptor dv_m68hc11spi_descriptor[] = { { "m68hc11spi", m68hc11spi_finish, }, { NULL }, };