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Diffstat (limited to 'arch/sh/boards/dreamcast/irq.c')
| -rw-r--r-- | arch/sh/boards/dreamcast/irq.c | 153 |
1 files changed, 0 insertions, 153 deletions
diff --git a/arch/sh/boards/dreamcast/irq.c b/arch/sh/boards/dreamcast/irq.c deleted file mode 100644 index 9d0673a9092..00000000000 --- a/arch/sh/boards/dreamcast/irq.c +++ /dev/null @@ -1,153 +0,0 @@ -/* - * arch/sh/boards/dreamcast/irq.c - * - * Holly IRQ support for the Sega Dreamcast. - * - * Copyright (c) 2001, 2002 M. R. Brown <mrbrown@0xd6.org> - * - * This file is part of the LinuxDC project (www.linuxdc.org) - * Released under the terms of the GNU GPL v2.0 - */ - -#include <linux/irq.h> -#include <asm/io.h> -#include <asm/irq.h> -#include <asm/dreamcast/sysasic.h> - -/* Dreamcast System ASIC Hardware Events - - - The Dreamcast's System ASIC (a.k.a. Holly) is responsible for receiving - hardware events from system peripherals and triggering an SH7750 IRQ. - Hardware events can trigger IRQs 13, 11, or 9 depending on which bits are - set in the Event Mask Registers (EMRs). When a hardware event is - triggered, it's corresponding bit in the Event Status Registers (ESRs) - is set, and that bit should be rewritten to the ESR to acknowledge that - event. - - There are three 32-bit ESRs located at 0xa05f8900 - 0xa05f6908. Event - types can be found in include/asm-sh/dreamcast/sysasic.h. There are three - groups of EMRs that parallel the ESRs. Each EMR group corresponds to an - IRQ, so 0xa05f6910 - 0xa05f6918 triggers IRQ 13, 0xa05f6920 - 0xa05f6928 - triggers IRQ 11, and 0xa05f6930 - 0xa05f6938 triggers IRQ 9. - - In the kernel, these events are mapped to virtual IRQs so that drivers can - respond to them as they would a normal interrupt. In order to keep this - mapping simple, the events are mapped as: - - 6900/6910 - Events 0-31, IRQ 13 - 6904/6924 - Events 32-63, IRQ 11 - 6908/6938 - Events 64-95, IRQ 9 - -*/ - -#define ESR_BASE 0x005f6900 /* Base event status register */ -#define EMR_BASE 0x005f6910 /* Base event mask register */ - -/* Helps us determine the EMR group that this event belongs to: 0 = 0x6910, - 1 = 0x6920, 2 = 0x6930; also determine the event offset */ -#define LEVEL(event) (((event) - HW_EVENT_IRQ_BASE) / 32) - -/* Return the hardware event's bit positon within the EMR/ESR */ -#define EVENT_BIT(event) (((event) - HW_EVENT_IRQ_BASE) & 31) - -/* For each of these *_irq routines, the IRQ passed in is the virtual IRQ - (logically mapped to the corresponding bit for the hardware event). */ - -/* Disable the hardware event by masking its bit in its EMR */ -static inline void disable_systemasic_irq(unsigned int irq) -{ - __u32 emr = EMR_BASE + (LEVEL(irq) << 4) + (LEVEL(irq) << 2); - __u32 mask; - - mask = inl(emr); - mask &= ~(1 << EVENT_BIT(irq)); - outl(mask, emr); -} - -/* Enable the hardware event by setting its bit in its EMR */ -static inline void enable_systemasic_irq(unsigned int irq) -{ - __u32 emr = EMR_BASE + (LEVEL(irq) << 4) + (LEVEL(irq) << 2); - __u32 mask; - - mask = inl(emr); - mask |= (1 << EVENT_BIT(irq)); - outl(mask, emr); -} - -/* Acknowledge a hardware event by writing its bit back to its ESR */ -static void ack_systemasic_irq(unsigned int irq) -{ - __u32 esr = ESR_BASE + (LEVEL(irq) << 2); - disable_systemasic_irq(irq); - outl((1 << EVENT_BIT(irq)), esr); -} - -/* After a IRQ has been ack'd and responded to, it needs to be renabled */ -static void end_systemasic_irq(unsigned int irq) -{ - if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS))) - enable_systemasic_irq(irq); -} - -static unsigned int startup_systemasic_irq(unsigned int irq) -{ - enable_systemasic_irq(irq); - - return 0; -} - -static void shutdown_systemasic_irq(unsigned int irq) -{ - disable_systemasic_irq(irq); -} - -struct hw_interrupt_type systemasic_int = { - .typename = "System ASIC", - .startup = startup_systemasic_irq, - .shutdown = shutdown_systemasic_irq, - .enable = enable_systemasic_irq, - .disable = disable_systemasic_irq, - .ack = ack_systemasic_irq, - .end = end_systemasic_irq, -}; - -/* - * Map the hardware event indicated by the processor IRQ to a virtual IRQ. - */ -int systemasic_irq_demux(int irq) -{ - __u32 emr, esr, status, level; - __u32 j, bit; - - switch (irq) { - case 13: - level = 0; - break; - case 11: - level = 1; - break; - case 9: - level = 2; - break; - default: - return irq; - } - emr = EMR_BASE + (level << 4) + (level << 2); - esr = ESR_BASE + (level << 2); - - /* Mask the ESR to filter any spurious, unwanted interrupts */ - status = inl(esr); - status &= inl(emr); - - /* Now scan and find the first set bit as the event to map */ - for (bit = 1, j = 0; j < 32; bit <<= 1, j++) { - if (status & bit) { - irq = HW_EVENT_IRQ_BASE + j + (level << 5); - return irq; - } - } - - /* Not reached */ - return irq; -} |