diff options
Diffstat (limited to 'arch/mips/momentum/ocelot_c/uart-irq.c')
| -rw-r--r-- | arch/mips/momentum/ocelot_c/uart-irq.c | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/arch/mips/momentum/ocelot_c/uart-irq.c b/arch/mips/momentum/ocelot_c/uart-irq.c new file mode 100644 index 0000000..ebe1507 --- /dev/null +++ b/arch/mips/momentum/ocelot_c/uart-irq.c @@ -0,0 +1,147 @@ +/* + * Copyright 2002 Momentum Computer + * Author: mdharm@momenco.com + * + * arch/mips/momentum/ocelot_c/uart-irq.c + * Interrupt routines for UARTs. Interrupt numbers are assigned from + * 80 to 81 (2 interrupt sources). + * + * 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. + */ + +#include <linux/module.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/kernel.h> +#include <asm/ptrace.h> +#include <linux/sched.h> +#include <linux/kernel_stat.h> +#include <asm/io.h> +#include <asm/irq.h> +#include "ocelot_c_fpga.h" + +static inline int ls1bit8(unsigned int x) +{ + int b = 7, s; + + s = 4; if (((unsigned char)(x << 4)) == 0) s = 0; b -= s; x <<= s; + s = 2; if (((unsigned char)(x << 2)) == 0) s = 0; b -= s; x <<= s; + s = 1; if (((unsigned char)(x << 1)) == 0) s = 0; b -= s; + + return b; +} + +/* mask off an interrupt -- 0 is enable, 1 is disable */ +static inline void mask_uart_irq(unsigned int irq) +{ + uint8_t value; + + value = OCELOT_FPGA_READ(UART_INTMASK); + value |= 1 << (irq - 74); + OCELOT_FPGA_WRITE(value, UART_INTMASK); + + /* read the value back to assure that it's really been written */ + value = OCELOT_FPGA_READ(UART_INTMASK); +} + +/* unmask an interrupt -- 0 is enable, 1 is disable */ +static inline void unmask_uart_irq(unsigned int irq) +{ + uint8_t value; + + value = OCELOT_FPGA_READ(UART_INTMASK); + value &= ~(1 << (irq - 74)); + OCELOT_FPGA_WRITE(value, UART_INTMASK); + + /* read the value back to assure that it's really been written */ + value = OCELOT_FPGA_READ(UART_INTMASK); +} + +/* + * Enables the IRQ in the FPGA + */ +static void enable_uart_irq(unsigned int irq) +{ + unmask_uart_irq(irq); +} + +/* + * Initialize the IRQ in the FPGA + */ +static unsigned int startup_uart_irq(unsigned int irq) +{ + unmask_uart_irq(irq); + return 0; +} + +/* + * Disables the IRQ in the FPGA + */ +static void disable_uart_irq(unsigned int irq) +{ + mask_uart_irq(irq); +} + +/* + * Masks and ACKs an IRQ + */ +static void mask_and_ack_uart_irq(unsigned int irq) +{ + mask_uart_irq(irq); +} + +/* + * End IRQ processing + */ +static void end_uart_irq(unsigned int irq) +{ + if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS))) + unmask_uart_irq(irq); +} + +/* + * Interrupt handler for interrupts coming from the FPGA chip. + */ +void ll_uart_irq(struct pt_regs *regs) +{ + unsigned int irq_src, irq_mask; + + /* read the interrupt status registers */ + irq_src = OCELOT_FPGA_READ(UART_INTSTAT); + irq_mask = OCELOT_FPGA_READ(UART_INTMASK); + + /* mask for just the interrupts we want */ + irq_src &= ~irq_mask; + + do_IRQ(ls1bit8(irq_src) + 74, regs); +} + +#define shutdown_uart_irq disable_uart_irq + +struct hw_interrupt_type uart_irq_type = { + "UART/FPGA", + startup_uart_irq, + shutdown_uart_irq, + enable_uart_irq, + disable_uart_irq, + mask_and_ack_uart_irq, + end_uart_irq, + NULL +}; + +void uart_irq_init(void) +{ + /* Reset irq handlers pointers to NULL */ + irq_desc[80].status = IRQ_DISABLED; + irq_desc[80].action = 0; + irq_desc[80].depth = 2; + irq_desc[80].handler = &uart_irq_type; + + irq_desc[81].status = IRQ_DISABLED; + irq_desc[81].action = 0; + irq_desc[81].depth = 2; + irq_desc[81].handler = &uart_irq_type; +} |