C++ IO_FIELD函数代码示例

static int __init
i2c_init(void)
{
	int res;

	/* Setup and enable the Port B I2C interface */

#ifndef CONFIG_ETRAX_I2C_USES_PB_NOT_PB_I2C
	*R_PORT_PB_I2C = port_pb_i2c_shadow |= 
		IO_STATE(R_PORT_PB_I2C, i2c_en,  on) |
		IO_FIELD(R_PORT_PB_I2C, i2c_d,   1)  |
		IO_FIELD(R_PORT_PB_I2C, i2c_clk, 1)  |
		IO_STATE(R_PORT_PB_I2C, i2c_oe_, enable);
#endif

	port_pb_dir_shadow &= ~IO_MASK(R_PORT_PB_DIR, dir0);
	port_pb_dir_shadow &= ~IO_MASK(R_PORT_PB_DIR, dir1);

	*R_PORT_PB_DIR = (port_pb_dir_shadow |=
			  IO_STATE(R_PORT_PB_DIR, dir0, input)  |
			  IO_STATE(R_PORT_PB_DIR, dir1, output));

	/* register char device */

	res = register_chrdev(I2C_MAJOR, i2c_name, &i2c_fops);
	if(res < 0) {
		printk(KERN_ERR "i2c: couldn't get a major number.\n");
		return res;
	}

	printk("I2C driver v2.2, (c) 1999-2001 Axis Communications AB\n");
	
	return 0;
}

void
flush_tlb_mm(struct mm_struct *mm)
{
	int i;
	int page_id = mm->context.page_id;
	unsigned long flags;

	D(printk("tlb: flush mm context %d (%p)\n", page_id, mm));

	if(page_id == NO_CONTEXT)
		return;


	local_irq_save(flags);
	for(i = 0; i < NUM_TLB_ENTRIES; i++) {
		*R_TLB_SELECT = IO_FIELD(R_TLB_SELECT, index, i);
		if (IO_EXTRACT(R_TLB_HI, page_id, *R_TLB_HI) == page_id) {
			*R_TLB_HI = ( IO_FIELD(R_TLB_HI, page_id, INVALID_PAGEID ) |
				      IO_FIELD(R_TLB_HI, vpn,     i & 0xf ) );

			*R_TLB_LO = ( IO_STATE(R_TLB_LO, global,no  ) |
				      IO_STATE(R_TLB_LO, valid, no  ) |
				      IO_STATE(R_TLB_LO, kernel,no  ) |
				      IO_STATE(R_TLB_LO, we,    no  ) |
				      IO_FIELD(R_TLB_LO, pfn,   0   ) );
		}
	}
	local_irq_restore(flags);
}

void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
{
	struct mm_struct *mm = vma->vm_mm;
	int page_id = mm->context.page_id;
	int i;
	unsigned long flags;

	D(printk("tlb: flush page %p in context %d (%p)\n", addr, page_id, mm));

	if(page_id == NO_CONTEXT)
		return;

	addr &= PAGE_MASK; 


	local_irq_save(flags);
	for(i = 0; i < NUM_TLB_ENTRIES; i++) {
		unsigned long tlb_hi;
		*R_TLB_SELECT = IO_FIELD(R_TLB_SELECT, index, i);
		tlb_hi = *R_TLB_HI;
		if (IO_EXTRACT(R_TLB_HI, page_id, tlb_hi) == page_id &&
		    (tlb_hi & PAGE_MASK) == addr) {
			*R_TLB_HI = IO_FIELD(R_TLB_HI, page_id, INVALID_PAGEID ) |
				addr; 

			*R_TLB_LO = ( IO_STATE(R_TLB_LO, global,no  ) |
				      IO_STATE(R_TLB_LO, valid, no  ) |
				      IO_STATE(R_TLB_LO, kernel,no  ) |
				      IO_STATE(R_TLB_LO, we,    no  ) |
				      IO_FIELD(R_TLB_LO, pfn,   0   ) );
		}
	}
	local_irq_restore(flags);
}

void
flush_tlb_all(void)
{
	int i;
	unsigned long flags;

	/* the vpn of i & 0xf is so we dont write similar TLB entries
	 * in the same 4-way entry group. details.. 
	 */

	save_and_cli(flags); /* flush needs to be atomic */
	for(i = 0; i < NUM_TLB_ENTRIES; i++) {
		*R_TLB_SELECT = ( IO_FIELD(R_TLB_SELECT, index, i) );
		*R_TLB_HI = ( IO_FIELD(R_TLB_HI, page_id, INVALID_PAGEID ) |
			      IO_FIELD(R_TLB_HI, vpn,     i & 0xf ) );
		
		*R_TLB_LO = ( IO_STATE(R_TLB_LO, global,no       ) |
			      IO_STATE(R_TLB_LO, valid, no       ) |
			      IO_STATE(R_TLB_LO, kernel,no	 ) |
			      IO_STATE(R_TLB_LO, we,    no       ) |
			      IO_FIELD(R_TLB_LO, pfn,   0        ) );
	}
	restore_flags(flags);
	D(printk("tlb: flushed all\n"));
}

static inline irqreturn_t
timer_interrupt(int irq, void *dev_id)
{
	struct pt_regs *regs = get_irq_regs();
	/* acknowledge the timer irq */

#ifdef USE_CASCADE_TIMERS
	*R_TIMER_CTRL =
		IO_FIELD( R_TIMER_CTRL, timerdiv1, 0) |
		IO_FIELD( R_TIMER_CTRL, timerdiv0, 0) |
		IO_STATE( R_TIMER_CTRL, i1, clr) |
		IO_STATE( R_TIMER_CTRL, tm1, run) |
		IO_STATE( R_TIMER_CTRL, clksel1, cascade0) |
		IO_STATE( R_TIMER_CTRL, i0, clr) |
		IO_STATE( R_TIMER_CTRL, tm0, run) |
		IO_STATE( R_TIMER_CTRL, clksel0, c6250kHz);
#else
	*R_TIMER_CTRL = r_timer_ctrl_shadow |
		IO_STATE(R_TIMER_CTRL, i0, clr);
#endif

	/* reset watchdog otherwise it resets us! */
	reset_watchdog();

	/* Update statistics. */
	update_process_times(user_mode(regs));

	/* call the real timer interrupt handler */

	do_timer(1);

        cris_do_profile(regs); /* Save profiling information */
        return IRQ_HANDLED;
}

void
flush_tlb_mm(struct mm_struct *mm)
{
	int i;
	int page_id = mm->context;
	unsigned long flags;

	D(printk("tlb: flush mm context %d (%p)\n", page_id, mm));

	if(page_id == NO_CONTEXT)
		return;
	
	/* mark the TLB entries that match the page_id as invalid.
	 * here we could also check the _PAGE_GLOBAL bit and NOT flush
	 * global pages. is it worth the extra I/O ? 
	 */

	save_and_cli(flags);  /* flush needs to be atomic */
	for(i = 0; i < NUM_TLB_ENTRIES; i++) {
		*R_TLB_SELECT = IO_FIELD(R_TLB_SELECT, index, i);
		if (IO_EXTRACT(R_TLB_HI, page_id, *R_TLB_HI) == page_id) {
			*R_TLB_HI = ( IO_FIELD(R_TLB_HI, page_id, INVALID_PAGEID ) |
				      IO_FIELD(R_TLB_HI, vpn,     i & 0xf ) );
			
			*R_TLB_LO = ( IO_STATE(R_TLB_LO, global,no  ) |
				      IO_STATE(R_TLB_LO, valid, no  ) |
				      IO_STATE(R_TLB_LO, kernel,no  ) |
				      IO_STATE(R_TLB_LO, we,    no  ) |
				      IO_FIELD(R_TLB_LO, pfn,   0   ) );
		}
	}
	restore_flags(flags);
}

static inline irqreturn_t
timer_interrupt(int irq, void *dev_id)
{
	struct pt_regs *regs = get_irq_regs();
	/* acknowledge the timer irq */

#ifdef USE_CASCADE_TIMERS
	*R_TIMER_CTRL =
		IO_FIELD( R_TIMER_CTRL, timerdiv1, 0) |
		IO_FIELD( R_TIMER_CTRL, timerdiv0, 0) |
		IO_STATE( R_TIMER_CTRL, i1, clr) |
		IO_STATE( R_TIMER_CTRL, tm1, run) |
		IO_STATE( R_TIMER_CTRL, clksel1, cascade0) |
		IO_STATE( R_TIMER_CTRL, i0, clr) |
		IO_STATE( R_TIMER_CTRL, tm0, run) |
		IO_STATE( R_TIMER_CTRL, clksel0, c6250kHz);
#else
	*R_TIMER_CTRL = r_timer_ctrl_shadow | 
		IO_STATE(R_TIMER_CTRL, i0, clr);
#endif

	/* reset watchdog otherwise it resets us! */
	reset_watchdog();
	
	/* Update statistics. */
	update_process_times(user_mode(regs));

	/* call the real timer interrupt handler */

	do_timer(1);
	
        cris_do_profile(regs); /* Save profiling information */

	/*
	 * If we have an externally synchronized Linux clock, then update
	 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
	 * called as close as possible to 500 ms before the new second starts.
	 *
	 * The division here is not time critical since it will run once in 
	 * 11 minutes
	 */
	if (ntp_synced() &&
	    xtime.tv_sec > last_rtc_update + 660 &&
	    (xtime.tv_nsec / 1000) >= 500000 - (tick_nsec / 1000) / 2 &&
	    (xtime.tv_nsec / 1000) <= 500000 + (tick_nsec / 1000) / 2) {
		if (set_rtc_mmss(xtime.tv_sec) == 0)
			last_rtc_update = xtime.tv_sec;
		else
			last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
	}
        return IRQ_HANDLED;
}

void switch_mm(struct mm_struct *prev, struct mm_struct *next,
	struct task_struct *tsk)
{
	if (prev != next) {
		/* make sure we have a context */
		get_mmu_context(next);

		/* remember the pgd for the fault handlers
		 * this is similar to the pgd register in some other CPU's.
		 * we need our own copy of it because current and active_mm
		 * might be invalid at points where we still need to derefer
		 * the pgd.
		 */

		per_cpu(current_pgd, smp_processor_id()) = next->pgd;

		/* switch context in the MMU */

		D(printk(KERN_DEBUG "switching mmu_context to %d (%p)\n",
			next->context, next));

		*R_MMU_CONTEXT = IO_FIELD(R_MMU_CONTEXT,
					  page_id, next->context.page_id);
	}
}

void hard_reset_now (void)
{
    /*
     * Don't declare this variable elsewhere.  We don't want any other
     * code to know about it than the watchdog handler in entry.S and
     * this code, implementing hard reset through the watchdog.
     */
#if defined(CONFIG_ETRAX_WATCHDOG) && !defined(CONFIG_SVINTO_SIM)
    extern int cause_of_death;
#endif

    printk("*** HARD RESET ***\n");
    local_irq_disable();

#if defined(CONFIG_ETRAX_WATCHDOG) && !defined(CONFIG_SVINTO_SIM)
    cause_of_death = 0xbedead;
#else
    /* Since we dont plan to keep on resetting the watchdog,
       the key can be arbitrary hence three */
    *R_WATCHDOG = IO_FIELD(R_WATCHDOG, key, 3) |
                  IO_STATE(R_WATCHDOG, enable, start);
#endif

    while(1) /* waiting for RETRIBUTION! */ ;
}

void
stop_watchdog(void)
{
#if defined(CONFIG_ETRAX_WATCHDOG) && !defined(CONFIG_SVINTO_SIM)
	watchdog_key ^= 0x7; /* invert key, which is 3 bits */
	*R_WATCHDOG = IO_FIELD(R_WATCHDOG, key, watchdog_key) |
		IO_STATE(R_WATCHDOG, enable, stop);
#endif
}

void
flush_tlb_range(struct mm_struct *mm, 
		unsigned long start,
		unsigned long end)
{
	int page_id = mm->context;
	int i;
	unsigned long flags;

	D(printk("tlb: flush range %p<->%p in context %d (%p)\n",
		 start, end, page_id, mm));

	if(page_id == NO_CONTEXT)
		return;

	start &= PAGE_MASK;  /* probably not necessary */
	end &= PAGE_MASK;    /* dito */

	/* invalidate those TLB entries that match both the mm context
	 * and the virtual address range
	 */

	save_and_cli(flags);  /* flush needs to be atomic */
	for(i = 0; i < NUM_TLB_ENTRIES; i++) {
		unsigned long tlb_hi, vpn;
		*R_TLB_SELECT = IO_FIELD(R_TLB_SELECT, index, i);
		tlb_hi = *R_TLB_HI;
		vpn = tlb_hi & PAGE_MASK;
		if (IO_EXTRACT(R_TLB_HI, page_id, tlb_hi) == page_id &&
		    vpn >= start && vpn < end) {
			*R_TLB_HI = ( IO_FIELD(R_TLB_HI, page_id, INVALID_PAGEID ) |
				      IO_FIELD(R_TLB_HI, vpn,     i & 0xf ) );
			
			*R_TLB_LO = ( IO_STATE(R_TLB_LO, global,no  ) |
				      IO_STATE(R_TLB_LO, valid, no  ) |
				      IO_STATE(R_TLB_LO, kernel,no  ) |
				      IO_STATE(R_TLB_LO, we,    no  ) |
				      IO_FIELD(R_TLB_LO, pfn,   0   ) );
		}
	}
	restore_flags(flags);
}

void
flush_tlb_page(struct vm_area_struct *vma, 
	       unsigned long addr)
{
	struct mm_struct *mm = vma->vm_mm;
	int page_id = mm->context;
	int i;
	unsigned long flags;

	D(printk("tlb: flush page %p in context %d (%p)\n", addr, page_id, mm));

	if(page_id == NO_CONTEXT)
		return;

	addr &= PAGE_MASK; /* perhaps not necessary */

	/* invalidate those TLB entries that match both the mm context
	 * and the virtual address requested 
	 */

	save_and_cli(flags);  /* flush needs to be atomic */
	for(i = 0; i < NUM_TLB_ENTRIES; i++) {
		unsigned long tlb_hi;
		*R_TLB_SELECT = IO_FIELD(R_TLB_SELECT, index, i);
		tlb_hi = *R_TLB_HI;
		if (IO_EXTRACT(R_TLB_HI, page_id, tlb_hi) == page_id &&
		    (tlb_hi & PAGE_MASK) == addr) {
			*R_TLB_HI = IO_FIELD(R_TLB_HI, page_id, INVALID_PAGEID ) |
				addr; /* same addr as before works. */
			
			*R_TLB_LO = ( IO_STATE(R_TLB_LO, global,no  ) |
				      IO_STATE(R_TLB_LO, valid, no  ) |
				      IO_STATE(R_TLB_LO, kernel,no  ) |
				      IO_STATE(R_TLB_LO, we,    no  ) |
				      IO_FIELD(R_TLB_LO, pfn,   0   ) );
		}
	}
	restore_flags(flags);
}

void
flush_tlb_all(void)
{
	int i;
	unsigned long flags;


	local_irq_save(flags);
	for(i = 0; i < NUM_TLB_ENTRIES; i++) {
		*R_TLB_SELECT = ( IO_FIELD(R_TLB_SELECT, index, i) );
		*R_TLB_HI = ( IO_FIELD(R_TLB_HI, page_id, INVALID_PAGEID ) |
			      IO_FIELD(R_TLB_HI, vpn,     i & 0xf ) );

		*R_TLB_LO = ( IO_STATE(R_TLB_LO, global,no       ) |
			      IO_STATE(R_TLB_LO, valid, no       ) |
			      IO_STATE(R_TLB_LO, kernel,no	 ) |
			      IO_STATE(R_TLB_LO, we,    no       ) |
			      IO_FIELD(R_TLB_LO, pfn,   0        ) );
	}
	local_irq_restore(flags);
	D(printk("tlb: flushed all\n"));
}

void
reset_watchdog(void)
{
#if defined(CONFIG_ETRAX_WATCHDOG) && !defined(CONFIG_SVINTO_SIM)
	/* only keep watchdog happy as long as we have memory left! */
	if(nr_free_pages() > WATCHDOG_MIN_FREE_PAGES) {
		/* reset the watchdog with the inverse of the old key */
		watchdog_key ^= 0x7; /* invert key, which is 3 bits */
		*R_WATCHDOG = IO_FIELD(R_WATCHDOG, key, watchdog_key) |
			IO_STATE(R_WATCHDOG, enable, start);
	}
#endif
}

void
dump_tlb_all(void)
{
	int i;
	unsigned long flags;
	
	printk("TLB dump. LO is: pfn | reserved | global | valid | kernel | we  |\n");

	save_and_cli(flags);
	for(i = 0; i < NUM_TLB_ENTRIES; i++) {
		*R_TLB_SELECT = ( IO_FIELD(R_TLB_SELECT, index, i) );
		printk("Entry %d: HI 0x%08lx, LO 0x%08lx\n",
		       i, *R_TLB_HI, *R_TLB_LO);
	}
	restore_flags(flags);
}