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m68k/atari: Remove code and comments about different irq types
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This code was obsoleted during the irq restructuring in 2006.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
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Geert Uytterhoeven committed Nov 8, 2011
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236 changes: 0 additions & 236 deletions arch/m68k/atari/ataints.c
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* <asm/atariints.h>): Autovector interrupts are 1..7, then follow ST-MFP,
* TT-MFP, SCC, and finally VME interrupts. Vector numbers for the latter can
* be allocated by atari_register_vme_int().
*
* Each interrupt can be of three types:
*
* - SLOW: The handler runs with all interrupts enabled, except the one it
* was called by (to avoid reentering). This should be the usual method.
* But it is currently possible only for MFP ints, since only the MFP
* offers an easy way to mask interrupts.
*
* - FAST: The handler runs with all interrupts disabled. This should be used
* only for really fast handlers, that just do actions immediately
* necessary, and let the rest do a bottom half or task queue.
*
* - PRIORITIZED: The handler can be interrupted by higher-level ints
* (greater IPL, no MFP priorities!). This is the method of choice for ints
* which should be slow, but are not from a MFP.
*
* The feature of more than one handler for one int source is still there, but
* only applicable if all handers are of the same type. To not slow down
* processing of ints with only one handler by the chaining feature, the list
* calling function atari_call_irq_list() is only plugged in at the time the
* second handler is registered.
*
* Implementation notes: For fast-as-possible int handling, there are separate
* entry points for each type (slow/fast/prio). The assembler handler calls
* the irq directly in the usual case, no C wrapper is involved. In case of
* multiple handlers, atari_call_irq_list() is registered as handler and calls
* in turn the real irq's. To ease access from assembler level to the irq
* function pointer and accompanying data, these two are stored in a separate
* array, irq_handler[]. The rest of data (type, name) are put into a second
* array, irq_param, that is accessed from C only. For each slow interrupt (32
* in all) there are separate handler functions, which makes it possible to
* hard-code the MFP register address and value, are necessary to mask the
* int. If there'd be only one generic function, lots of calculations would be
* needed to determine MFP register and int mask from the vector number :-(
*
* Furthermore, slow ints may not lower the IPL below its previous value
* (before the int happened). This is needed so that an int of class PRIO, on
* that this int may be stacked, cannot be reentered. This feature is
* implemented as follows: If the stack frame format is 1 (throwaway), the int
* is not stacked, and the IPL is anded with 0xfbff, resulting in a new level
* 2, which still blocks the HSYNC, but no interrupts of interest. If the
* frame format is 0, the int is nested, and the old IPL value can be found in
* the sr copy in the frame.
*/

#if 0

#define NUM_INT_SOURCES (8 + NUM_ATARI_SOURCES)

typedef void (*asm_irq_handler)(void);

struct irqhandler {
irqreturn_t (*handler)(int, void *, struct pt_regs *);
void *dev_id;
};

struct irqparam {
unsigned long flags;
const char *devname;
};

/*
* Array with irq's and their parameter data. This array is accessed from low
* level assembler code, so an element size of 8 allows usage of index scaling
* addressing mode.
*/
static struct irqhandler irq_handler[NUM_INT_SOURCES];

/*
* This array hold the rest of parameters of int handlers: type
* (slow,fast,prio) and the name of the handler. These values are only
* accessed from C
*/
static struct irqparam irq_param[NUM_INT_SOURCES];

/* check for valid int number (complex, sigh...) */
#define IS_VALID_INTNO(n) \
((n) > 0 && \
/* autovec and ST-MFP ok anyway */ \
(((n) < TTMFP_SOURCE_BASE) || \
/* TT-MFP ok if present */ \
((n) >= TTMFP_SOURCE_BASE && (n) < SCC_SOURCE_BASE && \
ATARIHW_PRESENT(TT_MFP)) || \
/* SCC ok if present and number even */ \
((n) >= SCC_SOURCE_BASE && (n) < VME_SOURCE_BASE && \
!((n) & 1) && ATARIHW_PRESENT(SCC)) || \
/* greater numbers ok if they are registered VME vectors */ \
((n) >= VME_SOURCE_BASE && (n) < VME_SOURCE_BASE + VME_MAX_SOURCES && \
free_vme_vec_bitmap & (1 << ((n) - VME_SOURCE_BASE)))))


/*
* Here start the assembler entry points for interrupts
*/

#define IRQ_NAME(nr) atari_slow_irq_##nr##_handler(void)

#define BUILD_SLOW_IRQ(n) \
asmlinkage void IRQ_NAME(n); \
/* Dummy function to allow asm with operands. */ \
void atari_slow_irq_##n##_dummy (void) { \
__asm__ (__ALIGN_STR "\n" \
"atari_slow_irq_" #n "_handler:\t" \
" addl %6,%5\n" /* preempt_count() += HARDIRQ_OFFSET */ \
SAVE_ALL_INT "\n" \
GET_CURRENT(%%d0) "\n" \
" andb #~(1<<(%c3&7)),%a4:w\n" /* mask this interrupt */ \
/* get old IPL from stack frame */ \
" bfextu %%sp@(%c2){#5,#3},%%d0\n" \
" movew %%sr,%%d1\n" \
" bfins %%d0,%%d1{#21,#3}\n" \
" movew %%d1,%%sr\n" /* set IPL = previous value */ \
" addql #1,%a0\n" \
" lea %a1,%%a0\n" \
" pea %%sp@\n" /* push addr of frame */ \
" movel %%a0@(4),%%sp@-\n" /* push handler data */ \
" pea (%c3+8)\n" /* push int number */ \
" movel %%a0@,%%a0\n" \
" jbsr %%a0@\n" /* call the handler */ \
" addql #8,%%sp\n" \
" addql #4,%%sp\n" \
" orw #0x0600,%%sr\n" \
" andw #0xfeff,%%sr\n" /* set IPL = 6 again */ \
" orb #(1<<(%c3&7)),%a4:w\n" /* now unmask the int again */ \
" jbra ret_from_interrupt\n" \
: : "i" (&kstat_cpu(0).irqs[n+8]), "i" (&irq_handler[n+8]), \
"n" (PT_OFF_SR), "n" (n), \
"i" (n & 8 ? (n & 16 ? &tt_mfp.int_mk_a : &st_mfp.int_mk_a) \
: (n & 16 ? &tt_mfp.int_mk_b : &st_mfp.int_mk_b)), \
"m" (preempt_count()), "di" (HARDIRQ_OFFSET) \
); \
for (;;); /* fake noreturn */ \
}

BUILD_SLOW_IRQ(0);
BUILD_SLOW_IRQ(1);
BUILD_SLOW_IRQ(2);
BUILD_SLOW_IRQ(3);
BUILD_SLOW_IRQ(4);
BUILD_SLOW_IRQ(5);
BUILD_SLOW_IRQ(6);
BUILD_SLOW_IRQ(7);
BUILD_SLOW_IRQ(8);
BUILD_SLOW_IRQ(9);
BUILD_SLOW_IRQ(10);
BUILD_SLOW_IRQ(11);
BUILD_SLOW_IRQ(12);
BUILD_SLOW_IRQ(13);
BUILD_SLOW_IRQ(14);
BUILD_SLOW_IRQ(15);
BUILD_SLOW_IRQ(16);
BUILD_SLOW_IRQ(17);
BUILD_SLOW_IRQ(18);
BUILD_SLOW_IRQ(19);
BUILD_SLOW_IRQ(20);
BUILD_SLOW_IRQ(21);
BUILD_SLOW_IRQ(22);
BUILD_SLOW_IRQ(23);
BUILD_SLOW_IRQ(24);
BUILD_SLOW_IRQ(25);
BUILD_SLOW_IRQ(26);
BUILD_SLOW_IRQ(27);
BUILD_SLOW_IRQ(28);
BUILD_SLOW_IRQ(29);
BUILD_SLOW_IRQ(30);
BUILD_SLOW_IRQ(31);

asm_irq_handler slow_handlers[32] = {
[0] = atari_slow_irq_0_handler,
[1] = atari_slow_irq_1_handler,
[2] = atari_slow_irq_2_handler,
[3] = atari_slow_irq_3_handler,
[4] = atari_slow_irq_4_handler,
[5] = atari_slow_irq_5_handler,
[6] = atari_slow_irq_6_handler,
[7] = atari_slow_irq_7_handler,
[8] = atari_slow_irq_8_handler,
[9] = atari_slow_irq_9_handler,
[10] = atari_slow_irq_10_handler,
[11] = atari_slow_irq_11_handler,
[12] = atari_slow_irq_12_handler,
[13] = atari_slow_irq_13_handler,
[14] = atari_slow_irq_14_handler,
[15] = atari_slow_irq_15_handler,
[16] = atari_slow_irq_16_handler,
[17] = atari_slow_irq_17_handler,
[18] = atari_slow_irq_18_handler,
[19] = atari_slow_irq_19_handler,
[20] = atari_slow_irq_20_handler,
[21] = atari_slow_irq_21_handler,
[22] = atari_slow_irq_22_handler,
[23] = atari_slow_irq_23_handler,
[24] = atari_slow_irq_24_handler,
[25] = atari_slow_irq_25_handler,
[26] = atari_slow_irq_26_handler,
[27] = atari_slow_irq_27_handler,
[28] = atari_slow_irq_28_handler,
[29] = atari_slow_irq_29_handler,
[30] = atari_slow_irq_30_handler,
[31] = atari_slow_irq_31_handler
};

asmlinkage void atari_fast_irq_handler( void );
asmlinkage void atari_prio_irq_handler( void );

/* Dummy function to allow asm with operands. */
void atari_fast_prio_irq_dummy (void) {
__asm__ (__ALIGN_STR "\n"
"atari_fast_irq_handler:\n\t"
"orw #0x700,%%sr\n" /* disable all interrupts */
"atari_prio_irq_handler:\n\t"
"addl %3,%2\n\t" /* preempt_count() += HARDIRQ_OFFSET */
SAVE_ALL_INT "\n\t"
GET_CURRENT(%%d0) "\n\t"
/* get vector number from stack frame and convert to source */
"bfextu %%sp@(%c1){#4,#10},%%d0\n\t"
"subw #(0x40-8),%%d0\n\t"
"jpl 1f\n\t"
"addw #(0x40-8-0x18),%%d0\n"
"1:\tlea %a0,%%a0\n\t"
"addql #1,%%a0@(%%d0:l:4)\n\t"
"lea irq_handler,%%a0\n\t"
"lea %%a0@(%%d0:l:8),%%a0\n\t"
"pea %%sp@\n\t" /* push frame address */
"movel %%a0@(4),%%sp@-\n\t" /* push handler data */
"movel %%d0,%%sp@-\n\t" /* push int number */
"movel %%a0@,%%a0\n\t"
"jsr %%a0@\n\t" /* and call the handler */
"addql #8,%%sp\n\t"
"addql #4,%%sp\n\t"
"jbra ret_from_interrupt"
: : "i" (&kstat_cpu(0).irqs), "n" (PT_OFF_FORMATVEC),
"m" (preempt_count()), "di" (HARDIRQ_OFFSET)
);
for (;;);
}
#endif

/*
* Bitmap for free interrupt vector numbers
* (new vectors starting from 0x70 can be allocated by
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