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sh: Convert Dreamcast support from hw_interrupt_type to irq_chip
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Switch the dreamcast IRQ code over to the irq_chip way of doing things,
so that we can set GENERIC_HARDIRQS_NO__DO_IRQ for all SuperH boards.

Also, whilst I'm here change some things to make checkpatch.pl happy:
	- Indent with tabs, not with spaces
	- Include <linux/io.h>, not <asm/io.h>
	- Fix the multi-line comment style
	- Fix some typos in the comments

Tested-by: Adrian McMenamin <adrian@newgolddream.dyndns.info>
Signed-off-by: Matt Fleming <mjf@gentoo.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
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Matt Fleming authored and Paul Mundt committed Dec 22, 2008
1 parent bd0a22d commit e85a477
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Showing 2 changed files with 91 additions and 106 deletions.
192 changes: 88 additions & 104 deletions arch/sh/boards/mach-dreamcast/irq.c
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Original file line number Diff line number Diff line change
Expand Up @@ -10,144 +10,128 @@
*/

#include <linux/irq.h>
#include <asm/io.h>
#include <linux/io.h>
#include <asm/irq.h>
#include <mach/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
*/
/*
* 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, its 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 0xa05f6900 - 0xa05f6908. Event
* types can be found in arch/sh/include/mach-dreamcast/mach/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 */
/*
* 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). */
/*
* 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;
__u32 emr = EMR_BASE + (LEVEL(irq) << 4) + (LEVEL(irq) << 2);
__u32 mask;

mask = inl(emr);
mask &= ~(1 << EVENT_BIT(irq));
outl(mask, emr);
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;
__u32 emr = EMR_BASE + (LEVEL(irq) << 4) + (LEVEL(irq) << 2);
__u32 mask;

mask = inl(emr);
mask |= (1 << EVENT_BIT(irq));
outl(mask, emr);
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)
static void mask_ack_systemasic_irq(unsigned int irq)
{
disable_systemasic_irq(irq);
__u32 esr = ESR_BASE + (LEVEL(irq) << 2);
disable_systemasic_irq(irq);
outl((1 << EVENT_BIT(irq)), esr);
}

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,
struct irq_chip systemasic_int = {
.name = "System ASIC",
.mask = disable_systemasic_irq,
.mask_ack = mask_ack_systemasic_irq,
.unmask = enable_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;
__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;
}
5 changes: 3 additions & 2 deletions arch/sh/boards/mach-dreamcast/setup.c
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Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,7 @@
#include <asm/machvec.h>
#include <mach/sysasic.h>

extern struct hw_interrupt_type systemasic_int;
extern struct irq_chip systemasic_int;
extern void aica_time_init(void);
extern int gapspci_init(void);
extern int systemasic_irq_demux(int);
Expand All @@ -47,7 +47,8 @@ static void __init dreamcast_setup(char **cmdline_p)

/* Assign all virtual IRQs to the System ASIC int. handler */
for (i = HW_EVENT_IRQ_BASE; i < HW_EVENT_IRQ_MAX; i++)
irq_desc[i].chip = &systemasic_int;
set_irq_chip_and_handler(i, &systemasic_int,
handle_level_irq);

board_time_init = aica_time_init;

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