arch/sh/mm/cache-sh4.c - kernel/msm-4.19 - Gitiles

 /*
  * arch/sh/mm/cache-sh4.c
  *
  * Copyright (C) 1999, 2000, 2002  Niibe Yutaka
  * Copyright (C) 2001 - 2007  Paul Mundt
  * Copyright (C) 2003  Richard Curnow
  * Copyright (c) 2007 STMicroelectronics (R&D) Ltd.
  *
  * This file is subject to the terms and conditions of the GNU General Public
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  */
 #include <linux/init.h>
 #include <linux/mm.h>
 #include <linux/io.h>
 #include <linux/mutex.h>
 #include <linux/fs.h>
 #include <asm/mmu_context.h>
 #include <asm/cacheflush.h>

 /*
  * The maximum number of pages we support up to when doing ranged dcache
  * flushing. Anything exceeding this will simply flush the dcache in its
  * entirety.
  */
 #define MAX_DCACHE_PAGES	64	/* XXX: Tune for ways */
 #define MAX_ICACHE_PAGES	32

 static void __flush_dcache_segment_1way(unsigned long start,
 					unsigned long extent);
 static void __flush_dcache_segment_2way(unsigned long start,
 					unsigned long extent);
 static void __flush_dcache_segment_4way(unsigned long start,
 					unsigned long extent);

 static void __flush_cache_4096(unsigned long addr, unsigned long phys,
 			       unsigned long exec_offset);

 /*
  * This is initialised here to ensure that it is not placed in the BSS.  If
  * that were to happen, note that cache_init gets called before the BSS is
  * cleared, so this would get nulled out which would be hopeless.
  */
 static void (*__flush_dcache_segment_fn)(unsigned long, unsigned long) =
 	(void (*)(unsigned long, unsigned long))0xdeadbeef;

 static void compute_alias(struct cache_info *c)
 {
 	c->alias_mask = ((c->sets - 1) << c->entry_shift) & ~(PAGE_SIZE - 1);
 	c->n_aliases = c->alias_mask ? (c->alias_mask >> PAGE_SHIFT) + 1 : 0;
 }

 static void __init emit_cache_params(void)
 {
 	printk("PVR=%08x CVR=%08x PRR=%08x\n",
 		ctrl_inl(CCN_PVR),
 		ctrl_inl(CCN_CVR),
 		ctrl_inl(CCN_PRR));
 	printk("I-cache : n_ways=%d n_sets=%d way_incr=%d\n",
 		boot_cpu_data.icache.ways,
 		boot_cpu_data.icache.sets,
 		boot_cpu_data.icache.way_incr);
 	printk("I-cache : entry_mask=0x%08x alias_mask=0x%08x n_aliases=%d\n",
 		boot_cpu_data.icache.entry_mask,
 		boot_cpu_data.icache.alias_mask,
 		boot_cpu_data.icache.n_aliases);
 	printk("D-cache : n_ways=%d n_sets=%d way_incr=%d\n",
 		boot_cpu_data.dcache.ways,
 		boot_cpu_data.dcache.sets,
 		boot_cpu_data.dcache.way_incr);
 	printk("D-cache : entry_mask=0x%08x alias_mask=0x%08x n_aliases=%d\n",
 		boot_cpu_data.dcache.entry_mask,
 		boot_cpu_data.dcache.alias_mask,
 		boot_cpu_data.dcache.n_aliases);

 	/*
 	 * Emit Secondary Cache parameters if the CPU has a probed L2.
 	 */
 	if (boot_cpu_data.flags & CPU_HAS_L2_CACHE) {
 		printk("S-cache : n_ways=%d n_sets=%d way_incr=%d\n",
 			boot_cpu_data.scache.ways,
 			boot_cpu_data.scache.sets,
 			boot_cpu_data.scache.way_incr);
 		printk("S-cache : entry_mask=0x%08x alias_mask=0x%08x n_aliases=%d\n",
 			boot_cpu_data.scache.entry_mask,
 			boot_cpu_data.scache.alias_mask,
 			boot_cpu_data.scache.n_aliases);
 	}

 	if (!__flush_dcache_segment_fn)
 		panic("unknown number of cache ways\n");
 }

 /*
  * SH-4 has virtually indexed and physically tagged cache.
  */
 void __init p3_cache_init(void)
 {
 	compute_alias(&boot_cpu_data.icache);
 	compute_alias(&boot_cpu_data.dcache);
 	compute_alias(&boot_cpu_data.scache);

 	switch (boot_cpu_data.dcache.ways) {
 	case 1:
 		__flush_dcache_segment_fn = __flush_dcache_segment_1way;
 		break;
 	case 2:
 		__flush_dcache_segment_fn = __flush_dcache_segment_2way;
 		break;
 	case 4:
 		__flush_dcache_segment_fn = __flush_dcache_segment_4way;
 		break;
 	default:
 		__flush_dcache_segment_fn = NULL;
 		break;
 	}

 	emit_cache_params();
 }

 /*
  * Write back the dirty D-caches, but not invalidate them.
  *
  * START: Virtual Address (U0, P1, or P3)
  * SIZE: Size of the region.
  */
 void __flush_wback_region(void *start, int size)
 {
 	unsigned long v;
 	unsigned long begin, end;

 	begin = (unsigned long)start & ~(L1_CACHE_BYTES-1);
 	end = ((unsigned long)start + size + L1_CACHE_BYTES-1)
 		& ~(L1_CACHE_BYTES-1);
 	for (v = begin; v < end; v+=L1_CACHE_BYTES) {
 		asm volatile("ocbwb	%0"
 			     : /* no output */
 			     : "m" (__m(v)));
 	}
 }

 /*
  * Write back the dirty D-caches and invalidate them.
  *
  * START: Virtual Address (U0, P1, or P3)
  * SIZE: Size of the region.
  */
 void __flush_purge_region(void *start, int size)
 {
 	unsigned long v;
 	unsigned long begin, end;

 	begin = (unsigned long)start & ~(L1_CACHE_BYTES-1);
 	end = ((unsigned long)start + size + L1_CACHE_BYTES-1)
 		& ~(L1_CACHE_BYTES-1);
 	for (v = begin; v < end; v+=L1_CACHE_BYTES) {
 		asm volatile("ocbp	%0"
 			     : /* no output */
 			     : "m" (__m(v)));
 	}
 }

 /*
  * No write back please
  */
 void __flush_invalidate_region(void *start, int size)
 {
 	unsigned long v;
 	unsigned long begin, end;

 	begin = (unsigned long)start & ~(L1_CACHE_BYTES-1);
 	end = ((unsigned long)start + size + L1_CACHE_BYTES-1)
 		& ~(L1_CACHE_BYTES-1);
 	for (v = begin; v < end; v+=L1_CACHE_BYTES) {
 		asm volatile("ocbi	%0"
 			     : /* no output */
 			     : "m" (__m(v)));
 	}
 }

 /*
  * Write back the range of D-cache, and purge the I-cache.
  *
  * Called from kernel/module.c:sys_init_module and routine for a.out format,
  * signal handler code and kprobes code
  */
 void flush_icache_range(unsigned long start, unsigned long end)
 {
 	int icacheaddr;
 	unsigned long flags, v;
 	int i;

        /* If there are too many pages then just blow the caches */
         if (((end - start) >> PAGE_SHIFT) >= MAX_ICACHE_PAGES) {
                 flush_cache_all();
        } else {
                /* selectively flush d-cache then invalidate the i-cache */
                /* this is inefficient, so only use for small ranges */
                start &= ~(L1_CACHE_BYTES-1);
                end += L1_CACHE_BYTES-1;
                end &= ~(L1_CACHE_BYTES-1);

                local_irq_save(flags);
                jump_to_uncached();

                for (v = start; v < end; v+=L1_CACHE_BYTES) {
                        asm volatile("ocbwb     %0"
                                     : /* no output */
                                     : "m" (__m(v)));

                        icacheaddr = CACHE_IC_ADDRESS_ARRAY | (
                                        v & cpu_data->icache.entry_mask);

                        for (i = 0; i < cpu_data->icache.ways;
                                i++, icacheaddr += cpu_data->icache.way_incr)
                                        /* Clear i-cache line valid-bit */
                                        ctrl_outl(0, icacheaddr);
                }

 		back_to_cached();
 		local_irq_restore(flags);
 	}
 }

 static inline void flush_cache_4096(unsigned long start,
 				    unsigned long phys)
 {
 	unsigned long flags, exec_offset = 0;

 	/*
 	 * All types of SH-4 require PC to be in P2 to operate on the I-cache.
 	 * Some types of SH-4 require PC to be in P2 to operate on the D-cache.
 	 */
 	if ((boot_cpu_data.flags & CPU_HAS_P2_FLUSH_BUG) ||
 	    (start < CACHE_OC_ADDRESS_ARRAY))
 		exec_offset = 0x20000000;

 	local_irq_save(flags);
 	__flush_cache_4096(start | SH_CACHE_ASSOC,
 			   P1SEGADDR(phys), exec_offset);
 	local_irq_restore(flags);
 }

 /*
  * Write back & invalidate the D-cache of the page.
  * (To avoid "alias" issues)
  */
 void flush_dcache_page(struct page *page)
 {
 	struct address_space *mapping = page_mapping(page);

 #ifndef CONFIG_SMP
 	if (mapping && !mapping_mapped(mapping))
 		set_bit(PG_dcache_dirty, &page->flags);
 	else
 #endif
 	{
 		unsigned long phys = PHYSADDR(page_address(page));
 		unsigned long addr = CACHE_OC_ADDRESS_ARRAY;
 		int i, n;

 		/* Loop all the D-cache */
 		n = boot_cpu_data.dcache.n_aliases;
 		for (i = 0; i < n; i++, addr += 4096)
 			flush_cache_4096(addr, phys);
 	}

 	wmb();
 }

 /* TODO: Selective icache invalidation through IC address array.. */
 static void __uses_jump_to_uncached flush_icache_all(void)
 {
 	unsigned long flags, ccr;

 	local_irq_save(flags);
 	jump_to_uncached();

 	/* Flush I-cache */
 	ccr = ctrl_inl(CCR);
 	ccr |= CCR_CACHE_ICI;
 	ctrl_outl(ccr, CCR);

 	/*
 	 * back_to_cached() will take care of the barrier for us, don't add
 	 * another one!
 	 */

 	back_to_cached();
 	local_irq_restore(flags);
 }

 void flush_dcache_all(void)
 {
 	(*__flush_dcache_segment_fn)(0UL, boot_cpu_data.dcache.way_size);
 	wmb();
 }

 void flush_cache_all(void)
 {
 	flush_dcache_all();
 	flush_icache_all();
 }

 static void __flush_cache_mm(struct mm_struct *mm, unsigned long start,
 			     unsigned long end)
 {
 	unsigned long d = 0, p = start & PAGE_MASK;
 	unsigned long alias_mask = boot_cpu_data.dcache.alias_mask;
 	unsigned long n_aliases = boot_cpu_data.dcache.n_aliases;
 	unsigned long select_bit;
 	unsigned long all_aliases_mask;
 	unsigned long addr_offset;
 	pgd_t *dir;
 	pmd_t *pmd;
 	pud_t *pud;
 	pte_t *pte;
 	int i;

 	dir = pgd_offset(mm, p);
 	pud = pud_offset(dir, p);
 	pmd = pmd_offset(pud, p);
 	end = PAGE_ALIGN(end);

 	all_aliases_mask = (1 << n_aliases) - 1;

 	do {
 		if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) {
 			p &= PMD_MASK;
 			p += PMD_SIZE;
 			pmd++;

 			continue;
 		}

 		pte = pte_offset_kernel(pmd, p);

 		do {
 			unsigned long phys;
 			pte_t entry = *pte;

 			if (!(pte_val(entry) & _PAGE_PRESENT)) {
 				pte++;
 				p += PAGE_SIZE;
 				continue;
 			}

 			phys = pte_val(entry) & PTE_PHYS_MASK;

 			if ((p ^ phys) & alias_mask) {
 				d |= 1 << ((p & alias_mask) >> PAGE_SHIFT);
 				d |= 1 << ((phys & alias_mask) >> PAGE_SHIFT);

 				if (d == all_aliases_mask)
 					goto loop_exit;
 			}

 			pte++;
 			p += PAGE_SIZE;
 		} while (p < end && ((unsigned long)pte & ~PAGE_MASK));
 		pmd++;
 	} while (p < end);

 loop_exit:
 	addr_offset = 0;
 	select_bit = 1;

 	for (i = 0; i < n_aliases; i++) {
 		if (d & select_bit) {
 			(*__flush_dcache_segment_fn)(addr_offset, PAGE_SIZE);
 			wmb();
 		}

 		select_bit <<= 1;
 		addr_offset += PAGE_SIZE;
 	}
 }

 /*
  * Note : (RPC) since the caches are physically tagged, the only point
  * of flush_cache_mm for SH-4 is to get rid of aliases from the
  * D-cache.  The assumption elsewhere, e.g. flush_cache_range, is that
  * lines can stay resident so long as the virtual address they were
  * accessed with (hence cache set) is in accord with the physical
  * address (i.e. tag).  It's no different here.  So I reckon we don't
  * need to flush the I-cache, since aliases don't matter for that.  We
  * should try that.
  *
  * Caller takes mm->mmap_sem.
  */
 void flush_cache_mm(struct mm_struct *mm)
 {
 	/*
 	 * If cache is only 4k-per-way, there are never any 'aliases'.  Since
 	 * the cache is physically tagged, the data can just be left in there.
 	 */
 	if (boot_cpu_data.dcache.n_aliases == 0)
 		return;

 	/*
 	 * Don't bother groveling around the dcache for the VMA ranges
 	 * if there are too many PTEs to make it worthwhile.
 	 */
 	if (mm->nr_ptes >= MAX_DCACHE_PAGES)
 		flush_dcache_all();
 	else {
 		struct vm_area_struct *vma;

 		/*
 		 * In this case there are reasonably sized ranges to flush,
 		 * iterate through the VMA list and take care of any aliases.
 		 */
 		for (vma = mm->mmap; vma; vma = vma->vm_next)
 			__flush_cache_mm(mm, vma->vm_start, vma->vm_end);
 	}

 	/* Only touch the icache if one of the VMAs has VM_EXEC set. */
 	if (mm->exec_vm)
 		flush_icache_all();
 }

 /*
  * Write back and invalidate I/D-caches for the page.
  *
  * ADDR: Virtual Address (U0 address)
  * PFN: Physical page number
  */
 void flush_cache_page(struct vm_area_struct *vma, unsigned long address,
 		      unsigned long pfn)
 {
 	unsigned long phys = pfn << PAGE_SHIFT;
 	unsigned int alias_mask;

 	alias_mask = boot_cpu_data.dcache.alias_mask;

 	/* We only need to flush D-cache when we have alias */
 	if ((address^phys) & alias_mask) {
 		/* Loop 4K of the D-cache */
 		flush_cache_4096(
 			CACHE_OC_ADDRESS_ARRAY | (address & alias_mask),
 			phys);
 		/* Loop another 4K of the D-cache */
 		flush_cache_4096(
 			CACHE_OC_ADDRESS_ARRAY | (phys & alias_mask),
 			phys);
 	}

 	alias_mask = boot_cpu_data.icache.alias_mask;
 	if (vma->vm_flags & VM_EXEC) {
 		/*
 		 * Evict entries from the portion of the cache from which code
 		 * may have been executed at this address (virtual).  There's
 		 * no need to evict from the portion corresponding to the
 		 * physical address as for the D-cache, because we know the
 		 * kernel has never executed the code through its identity
 		 * translation.
 		 */
 		flush_cache_4096(
 			CACHE_IC_ADDRESS_ARRAY | (address & alias_mask),
 			phys);
 	}
 }

 /*
  * Write back and invalidate D-caches.
  *
  * START, END: Virtual Address (U0 address)
  *
  * NOTE: We need to flush the _physical_ page entry.
  * Flushing the cache lines for U0 only isn't enough.
  * We need to flush for P1 too, which may contain aliases.
  */
 void flush_cache_range(struct vm_area_struct *vma, unsigned long start,
 		       unsigned long end)
 {
 	/*
 	 * If cache is only 4k-per-way, there are never any 'aliases'.  Since
 	 * the cache is physically tagged, the data can just be left in there.
 	 */
 	if (boot_cpu_data.dcache.n_aliases == 0)
 		return;

 	/*
 	 * Don't bother with the lookup and alias check if we have a
 	 * wide range to cover, just blow away the dcache in its
 	 * entirety instead. -- PFM.
 	 */
 	if (((end - start) >> PAGE_SHIFT) >= MAX_DCACHE_PAGES)
 		flush_dcache_all();
 	else
 		__flush_cache_mm(vma->vm_mm, start, end);

 	if (vma->vm_flags & VM_EXEC) {
 		/*
 		 * TODO: Is this required???  Need to look at how I-cache
 		 * coherency is assured when new programs are loaded to see if
 		 * this matters.
 		 */
 		flush_icache_all();
 	}
 }

 /*
  * flush_icache_user_range
  * @vma: VMA of the process
  * @page: page
  * @addr: U0 address
  * @len: length of the range (< page size)
  */
 void flush_icache_user_range(struct vm_area_struct *vma,
 			     struct page *page, unsigned long addr, int len)
 {
 	flush_cache_page(vma, addr, page_to_pfn(page));
 	mb();
 }

 /**
  * __flush_cache_4096
  *
  * @addr:  address in memory mapped cache array
  * @phys:  P1 address to flush (has to match tags if addr has 'A' bit
  *         set i.e. associative write)
  * @exec_offset: set to 0x20000000 if flush has to be executed from P2
  *               region else 0x0
  *
  * The offset into the cache array implied by 'addr' selects the
  * 'colour' of the virtual address range that will be flushed.  The
  * operation (purge/write-back) is selected by the lower 2 bits of
  * 'phys'.
  */
 static void __flush_cache_4096(unsigned long addr, unsigned long phys,
 			       unsigned long exec_offset)
 {
 	int way_count;
 	unsigned long base_addr = addr;
 	struct cache_info *dcache;
 	unsigned long way_incr;
 	unsigned long a, ea, p;
 	unsigned long temp_pc;

 	dcache = &boot_cpu_data.dcache;
 	/* Write this way for better assembly. */
 	way_count = dcache->ways;
 	way_incr = dcache->way_incr;

 	/*
 	 * Apply exec_offset (i.e. branch to P2 if required.).
 	 *
 	 * FIXME:
 	 *
 	 *	If I write "=r" for the (temp_pc), it puts this in r6 hence
 	 *	trashing exec_offset before it's been added on - why?  Hence
 	 *	"=&r" as a 'workaround'
 	 */
 	asm volatile("mov.l 1f, %0\n\t"
 		     "add   %1, %0\n\t"
 		     "jmp   @%0\n\t"
 		     "nop\n\t"
 		     ".balign 4\n\t"
 		     "1:  .long 2f\n\t"
 		     "2:\n" : "=&r" (temp_pc) : "r" (exec_offset));

 	/*
 	 * We know there will be >=1 iteration, so write as do-while to avoid
 	 * pointless nead-of-loop check for 0 iterations.
 	 */
 	do {
 		ea = base_addr + PAGE_SIZE;
 		a = base_addr;
 		p = phys;

 		do {
 			*(volatile unsigned long *)a = p;
 			/*
 			 * Next line: intentionally not p+32, saves an add, p
 			 * will do since only the cache tag bits need to
 			 * match.
 			 */
 			*(volatile unsigned long *)(a+32) = p;
 			a += 64;
 			p += 64;
 		} while (a < ea);

 		base_addr += way_incr;
 	} while (--way_count != 0);
 }

 /*
  * Break the 1, 2 and 4 way variants of this out into separate functions to
  * avoid nearly all the overhead of having the conditional stuff in the function
  * bodies (+ the 1 and 2 way cases avoid saving any registers too).
  */
 static void __flush_dcache_segment_1way(unsigned long start,
 					unsigned long extent_per_way)
 {
 	unsigned long orig_sr, sr_with_bl;
 	unsigned long base_addr;
 	unsigned long way_incr, linesz, way_size;
 	struct cache_info *dcache;
 	register unsigned long a0, a0e;

 	asm volatile("stc sr, %0" : "=r" (orig_sr));
 	sr_with_bl = orig_sr | (1<<28);
 	base_addr = ((unsigned long)&empty_zero_page[0]);

 	/*
 	 * The previous code aligned base_addr to 16k, i.e. the way_size of all
 	 * existing SH-4 D-caches.  Whilst I don't see a need to have this
 	 * aligned to any better than the cache line size (which it will be
 	 * anyway by construction), let's align it to at least the way_size of
 	 * any existing or conceivable SH-4 D-cache.  -- RPC
 	 */
 	base_addr = ((base_addr >> 16) << 16);
 	base_addr |= start;

 	dcache = &boot_cpu_data.dcache;
 	linesz = dcache->linesz;
 	way_incr = dcache->way_incr;
 	way_size = dcache->way_size;

 	a0 = base_addr;
 	a0e = base_addr + extent_per_way;
 	do {
 		asm volatile("ldc %0, sr" : : "r" (sr_with_bl));
 		asm volatile("movca.l r0, @%0\n\t"
 			     "ocbi @%0" : : "r" (a0));
 		a0 += linesz;
 		asm volatile("movca.l r0, @%0\n\t"
 			     "ocbi @%0" : : "r" (a0));
 		a0 += linesz;
 		asm volatile("movca.l r0, @%0\n\t"
 			     "ocbi @%0" : : "r" (a0));
 		a0 += linesz;
 		asm volatile("movca.l r0, @%0\n\t"
 			     "ocbi @%0" : : "r" (a0));
 		asm volatile("ldc %0, sr" : : "r" (orig_sr));
 		a0 += linesz;
 	} while (a0 < a0e);
 }

 static void __flush_dcache_segment_2way(unsigned long start,
 					unsigned long extent_per_way)
 {
 	unsigned long orig_sr, sr_with_bl;
 	unsigned long base_addr;
 	unsigned long way_incr, linesz, way_size;
 	struct cache_info *dcache;
 	register unsigned long a0, a1, a0e;

 	asm volatile("stc sr, %0" : "=r" (orig_sr));
 	sr_with_bl = orig_sr | (1<<28);
 	base_addr = ((unsigned long)&empty_zero_page[0]);

 	/* See comment under 1-way above */
 	base_addr = ((base_addr >> 16) << 16);
 	base_addr |= start;

 	dcache = &boot_cpu_data.dcache;
 	linesz = dcache->linesz;
 	way_incr = dcache->way_incr;
 	way_size = dcache->way_size;

 	a0 = base_addr;
 	a1 = a0 + way_incr;
 	a0e = base_addr + extent_per_way;
 	do {
 		asm volatile("ldc %0, sr" : : "r" (sr_with_bl));
 		asm volatile("movca.l r0, @%0\n\t"
 			     "movca.l r0, @%1\n\t"
 			     "ocbi @%0\n\t"
 			     "ocbi @%1" : :
 			     "r" (a0), "r" (a1));
 		a0 += linesz;
 		a1 += linesz;
 		asm volatile("movca.l r0, @%0\n\t"
 			     "movca.l r0, @%1\n\t"
 			     "ocbi @%0\n\t"
 			     "ocbi @%1" : :
 			     "r" (a0), "r" (a1));
 		a0 += linesz;
 		a1 += linesz;
 		asm volatile("movca.l r0, @%0\n\t"
 			     "movca.l r0, @%1\n\t"
 			     "ocbi @%0\n\t"
 			     "ocbi @%1" : :
 			     "r" (a0), "r" (a1));
 		a0 += linesz;
 		a1 += linesz;
 		asm volatile("movca.l r0, @%0\n\t"
 			     "movca.l r0, @%1\n\t"
 			     "ocbi @%0\n\t"
 			     "ocbi @%1" : :
 			     "r" (a0), "r" (a1));
 		asm volatile("ldc %0, sr" : : "r" (orig_sr));
 		a0 += linesz;
 		a1 += linesz;
 	} while (a0 < a0e);
 }

 static void __flush_dcache_segment_4way(unsigned long start,
 					unsigned long extent_per_way)
 {
 	unsigned long orig_sr, sr_with_bl;
 	unsigned long base_addr;
 	unsigned long way_incr, linesz, way_size;
 	struct cache_info *dcache;
 	register unsigned long a0, a1, a2, a3, a0e;

 	asm volatile("stc sr, %0" : "=r" (orig_sr));
 	sr_with_bl = orig_sr | (1<<28);
 	base_addr = ((unsigned long)&empty_zero_page[0]);

 	/* See comment under 1-way above */
 	base_addr = ((base_addr >> 16) << 16);
 	base_addr |= start;

 	dcache = &boot_cpu_data.dcache;
 	linesz = dcache->linesz;
 	way_incr = dcache->way_incr;
 	way_size = dcache->way_size;

 	a0 = base_addr;
 	a1 = a0 + way_incr;
 	a2 = a1 + way_incr;
 	a3 = a2 + way_incr;
 	a0e = base_addr + extent_per_way;
 	do {
 		asm volatile("ldc %0, sr" : : "r" (sr_with_bl));
 		asm volatile("movca.l r0, @%0\n\t"
 			     "movca.l r0, @%1\n\t"
 			     "movca.l r0, @%2\n\t"
 			     "movca.l r0, @%3\n\t"
 			     "ocbi @%0\n\t"
 			     "ocbi @%1\n\t"
 			     "ocbi @%2\n\t"
 			     "ocbi @%3\n\t" : :
 			     "r" (a0), "r" (a1), "r" (a2), "r" (a3));
 		a0 += linesz;
 		a1 += linesz;
 		a2 += linesz;
 		a3 += linesz;
 		asm volatile("movca.l r0, @%0\n\t"
 			     "movca.l r0, @%1\n\t"
 			     "movca.l r0, @%2\n\t"
 			     "movca.l r0, @%3\n\t"
 			     "ocbi @%0\n\t"
 			     "ocbi @%1\n\t"
 			     "ocbi @%2\n\t"
 			     "ocbi @%3\n\t" : :
 			     "r" (a0), "r" (a1), "r" (a2), "r" (a3));
 		a0 += linesz;
 		a1 += linesz;
 		a2 += linesz;
 		a3 += linesz;
 		asm volatile("movca.l r0, @%0\n\t"
 			     "movca.l r0, @%1\n\t"
 			     "movca.l r0, @%2\n\t"
 			     "movca.l r0, @%3\n\t"
 			     "ocbi @%0\n\t"
 			     "ocbi @%1\n\t"
 			     "ocbi @%2\n\t"
 			     "ocbi @%3\n\t" : :
 			     "r" (a0), "r" (a1), "r" (a2), "r" (a3));
 		a0 += linesz;
 		a1 += linesz;
 		a2 += linesz;
 		a3 += linesz;
 		asm volatile("movca.l r0, @%0\n\t"
 			     "movca.l r0, @%1\n\t"
 			     "movca.l r0, @%2\n\t"
 			     "movca.l r0, @%3\n\t"
 			     "ocbi @%0\n\t"
 			     "ocbi @%1\n\t"
 			     "ocbi @%2\n\t"
 			     "ocbi @%3\n\t" : :
 			     "r" (a0), "r" (a1), "r" (a2), "r" (a3));
 		asm volatile("ldc %0, sr" : : "r" (orig_sr));
 		a0 += linesz;
 		a1 += linesz;
 		a2 += linesz;
 		a3 += linesz;
 	} while (a0 < a0e);
 }
	/*
	* arch/sh/mm/cache-sh4.c
	*
	* Copyright (C) 1999, 2000, 2002 Niibe Yutaka
	* Copyright (C) 2001 - 2007 Paul Mundt
	* Copyright (C) 2003 Richard Curnow
	* Copyright (c) 2007 STMicroelectronics (R&D) Ltd.
	*
	* This file is subject to the terms and conditions of the GNU General Public
	* License. See the file "COPYING" in the main directory of this archive
	* for more details.
	*/
	#include <linux/init.h>
	#include <linux/mm.h>
	#include <linux/io.h>
	#include <linux/mutex.h>
	#include <linux/fs.h>
	#include <asm/mmu_context.h>
	#include <asm/cacheflush.h>

	/*
	* The maximum number of pages we support up to when doing ranged dcache
	* flushing. Anything exceeding this will simply flush the dcache in its
	* entirety.
	*/
	#define MAX_DCACHE_PAGES 64 /* XXX: Tune for ways */
	#define MAX_ICACHE_PAGES 32

	static void __flush_dcache_segment_1way(unsigned long start,
	unsigned long extent);
	static void __flush_dcache_segment_2way(unsigned long start,
	unsigned long extent);
	static void __flush_dcache_segment_4way(unsigned long start,
	unsigned long extent);

	static void __flush_cache_4096(unsigned long addr, unsigned long phys,
	unsigned long exec_offset);

	/*
	* This is initialised here to ensure that it is not placed in the BSS. If
	* that were to happen, note that cache_init gets called before the BSS is
	* cleared, so this would get nulled out which would be hopeless.
	*/
	static void (*__flush_dcache_segment_fn)(unsigned long, unsigned long) =
	(void (*)(unsigned long, unsigned long))0xdeadbeef;

	static void compute_alias(struct cache_info *c)
	{
	c->alias_mask = ((c->sets - 1) << c->entry_shift) & ~(PAGE_SIZE - 1);
	c->n_aliases = c->alias_mask ? (c->alias_mask >> PAGE_SHIFT) + 1 : 0;
	}

	static void __init emit_cache_params(void)
	{
	printk("PVR=%08x CVR=%08x PRR=%08x\n",
	ctrl_inl(CCN_PVR),
	ctrl_inl(CCN_CVR),
	ctrl_inl(CCN_PRR));
	printk("I-cache : n_ways=%d n_sets=%d way_incr=%d\n",
	boot_cpu_data.icache.ways,
	boot_cpu_data.icache.sets,
	boot_cpu_data.icache.way_incr);
	printk("I-cache : entry_mask=0x%08x alias_mask=0x%08x n_aliases=%d\n",
	boot_cpu_data.icache.entry_mask,
	boot_cpu_data.icache.alias_mask,
	boot_cpu_data.icache.n_aliases);
	printk("D-cache : n_ways=%d n_sets=%d way_incr=%d\n",
	boot_cpu_data.dcache.ways,
	boot_cpu_data.dcache.sets,
	boot_cpu_data.dcache.way_incr);
	printk("D-cache : entry_mask=0x%08x alias_mask=0x%08x n_aliases=%d\n",
	boot_cpu_data.dcache.entry_mask,
	boot_cpu_data.dcache.alias_mask,
	boot_cpu_data.dcache.n_aliases);

	/*
	* Emit Secondary Cache parameters if the CPU has a probed L2.
	*/
	if (boot_cpu_data.flags & CPU_HAS_L2_CACHE) {
	printk("S-cache : n_ways=%d n_sets=%d way_incr=%d\n",
	boot_cpu_data.scache.ways,
	boot_cpu_data.scache.sets,
	boot_cpu_data.scache.way_incr);
	printk("S-cache : entry_mask=0x%08x alias_mask=0x%08x n_aliases=%d\n",
	boot_cpu_data.scache.entry_mask,
	boot_cpu_data.scache.alias_mask,
	boot_cpu_data.scache.n_aliases);
	}

	if (!__flush_dcache_segment_fn)
	panic("unknown number of cache ways\n");
	}

	/*
	* SH-4 has virtually indexed and physically tagged cache.
	*/
	void __init p3_cache_init(void)
	{
	compute_alias(&boot_cpu_data.icache);
	compute_alias(&boot_cpu_data.dcache);
	compute_alias(&boot_cpu_data.scache);

	switch (boot_cpu_data.dcache.ways) {
	case 1:
	__flush_dcache_segment_fn = __flush_dcache_segment_1way;
	break;
	case 2:
	__flush_dcache_segment_fn = __flush_dcache_segment_2way;
	break;
	case 4:
	__flush_dcache_segment_fn = __flush_dcache_segment_4way;
	break;
	default:
	__flush_dcache_segment_fn = NULL;
	break;
	}

	emit_cache_params();
	}

	/*
	* Write back the dirty D-caches, but not invalidate them.
	*
	* START: Virtual Address (U0, P1, or P3)
	* SIZE: Size of the region.
	*/
	void __flush_wback_region(void *start, int size)
	{
	unsigned long v;
	unsigned long begin, end;

	begin = (unsigned long)start & ~(L1_CACHE_BYTES-1);
	end = ((unsigned long)start + size + L1_CACHE_BYTES-1)
	& ~(L1_CACHE_BYTES-1);
	for (v = begin; v < end; v+=L1_CACHE_BYTES) {
	asm volatile("ocbwb %0"
	: /* no output */
	: "m" (__m(v)));
	}
	}

	/*
	* Write back the dirty D-caches and invalidate them.
	*
	* START: Virtual Address (U0, P1, or P3)
	* SIZE: Size of the region.
	*/
	void __flush_purge_region(void *start, int size)
	{
	unsigned long v;
	unsigned long begin, end;

	begin = (unsigned long)start & ~(L1_CACHE_BYTES-1);
	end = ((unsigned long)start + size + L1_CACHE_BYTES-1)
	& ~(L1_CACHE_BYTES-1);
	for (v = begin; v < end; v+=L1_CACHE_BYTES) {
	asm volatile("ocbp %0"
	: /* no output */
	: "m" (__m(v)));
	}
	}

	/*
	* No write back please
	*/
	void __flush_invalidate_region(void *start, int size)
	{
	unsigned long v;
	unsigned long begin, end;

	begin = (unsigned long)start & ~(L1_CACHE_BYTES-1);
	end = ((unsigned long)start + size + L1_CACHE_BYTES-1)
	& ~(L1_CACHE_BYTES-1);
	for (v = begin; v < end; v+=L1_CACHE_BYTES) {
	asm volatile("ocbi %0"
	: /* no output */
	: "m" (__m(v)));
	}
	}

	/*
	* Write back the range of D-cache, and purge the I-cache.
	*
	* Called from kernel/module.c:sys_init_module and routine for a.out format,
	* signal handler code and kprobes code
	*/
	void flush_icache_range(unsigned long start, unsigned long end)
	{
	int icacheaddr;
	unsigned long flags, v;
	int i;

	/* If there are too many pages then just blow the caches */
	if (((end - start) >> PAGE_SHIFT) >= MAX_ICACHE_PAGES) {
	flush_cache_all();
	} else {
	/* selectively flush d-cache then invalidate the i-cache */
	/* this is inefficient, so only use for small ranges */
	start &= ~(L1_CACHE_BYTES-1);
	end += L1_CACHE_BYTES-1;
	end &= ~(L1_CACHE_BYTES-1);

	local_irq_save(flags);
	jump_to_uncached();

	for (v = start; v < end; v+=L1_CACHE_BYTES) {
	asm volatile("ocbwb %0"
	: /* no output */
	: "m" (__m(v)));

	icacheaddr = CACHE_IC_ADDRESS_ARRAY \| (
	v & cpu_data->icache.entry_mask);

	for (i = 0; i < cpu_data->icache.ways;
	i++, icacheaddr += cpu_data->icache.way_incr)
	/* Clear i-cache line valid-bit */
	ctrl_outl(0, icacheaddr);
	}

	back_to_cached();
	local_irq_restore(flags);
	}
	}

	static inline void flush_cache_4096(unsigned long start,
	unsigned long phys)
	{
	unsigned long flags, exec_offset = 0;

	/*
	* All types of SH-4 require PC to be in P2 to operate on the I-cache.
	* Some types of SH-4 require PC to be in P2 to operate on the D-cache.
	*/
	if ((boot_cpu_data.flags & CPU_HAS_P2_FLUSH_BUG) \|\|
	(start < CACHE_OC_ADDRESS_ARRAY))
	exec_offset = 0x20000000;

	local_irq_save(flags);
	__flush_cache_4096(start \| SH_CACHE_ASSOC,
	P1SEGADDR(phys), exec_offset);
	local_irq_restore(flags);
	}

	/*
	* Write back & invalidate the D-cache of the page.
	* (To avoid "alias" issues)
	*/
	void flush_dcache_page(struct page *page)
	{
	struct address_space *mapping = page_mapping(page);

	#ifndef CONFIG_SMP
	if (mapping && !mapping_mapped(mapping))
	set_bit(PG_dcache_dirty, &page->flags);
	else
	#endif
	{
	unsigned long phys = PHYSADDR(page_address(page));
	unsigned long addr = CACHE_OC_ADDRESS_ARRAY;
	int i, n;

	/* Loop all the D-cache */
	n = boot_cpu_data.dcache.n_aliases;
	for (i = 0; i < n; i++, addr += 4096)
	flush_cache_4096(addr, phys);
	}

	wmb();
	}

	/* TODO: Selective icache invalidation through IC address array.. */
	static void __uses_jump_to_uncached flush_icache_all(void)
	{
	unsigned long flags, ccr;

	local_irq_save(flags);
	jump_to_uncached();

	/* Flush I-cache */
	ccr = ctrl_inl(CCR);
	ccr \|= CCR_CACHE_ICI;
	ctrl_outl(ccr, CCR);

	/*
	* back_to_cached() will take care of the barrier for us, don't add
	* another one!
	*/

	back_to_cached();
	local_irq_restore(flags);
	}

	void flush_dcache_all(void)
	{
	(*__flush_dcache_segment_fn)(0UL, boot_cpu_data.dcache.way_size);
	wmb();
	}

	void flush_cache_all(void)
	{
	flush_dcache_all();
	flush_icache_all();
	}

	static void __flush_cache_mm(struct mm_struct *mm, unsigned long start,
	unsigned long end)
	{
	unsigned long d = 0, p = start & PAGE_MASK;
	unsigned long alias_mask = boot_cpu_data.dcache.alias_mask;
	unsigned long n_aliases = boot_cpu_data.dcache.n_aliases;
	unsigned long select_bit;
	unsigned long all_aliases_mask;
	unsigned long addr_offset;
	pgd_t *dir;
	pmd_t *pmd;
	pud_t *pud;
	pte_t *pte;
	int i;

	dir = pgd_offset(mm, p);
	pud = pud_offset(dir, p);
	pmd = pmd_offset(pud, p);
	end = PAGE_ALIGN(end);

	all_aliases_mask = (1 << n_aliases) - 1;

	do {
	if (pmd_none(pmd) \|\| unlikely(pmd_bad(pmd))) {
	p &= PMD_MASK;
	p += PMD_SIZE;
	pmd++;

	continue;
	}

	pte = pte_offset_kernel(pmd, p);

	do {
	unsigned long phys;
	pte_t entry = *pte;

	if (!(pte_val(entry) & _PAGE_PRESENT)) {
	pte++;
	p += PAGE_SIZE;
	continue;
	}

	phys = pte_val(entry) & PTE_PHYS_MASK;

	if ((p ^ phys) & alias_mask) {
	d \|= 1 << ((p & alias_mask) >> PAGE_SHIFT);
	d \|= 1 << ((phys & alias_mask) >> PAGE_SHIFT);

	if (d == all_aliases_mask)
	goto loop_exit;
	}

	pte++;
	p += PAGE_SIZE;
	} while (p < end && ((unsigned long)pte & ~PAGE_MASK));
	pmd++;
	} while (p < end);

	loop_exit:
	addr_offset = 0;
	select_bit = 1;

	for (i = 0; i < n_aliases; i++) {
	if (d & select_bit) {
	(*__flush_dcache_segment_fn)(addr_offset, PAGE_SIZE);
	wmb();
	}

	select_bit <<= 1;
	addr_offset += PAGE_SIZE;
	}
	}

	/*
	* Note : (RPC) since the caches are physically tagged, the only point
	* of flush_cache_mm for SH-4 is to get rid of aliases from the
	* D-cache. The assumption elsewhere, e.g. flush_cache_range, is that
	* lines can stay resident so long as the virtual address they were
	* accessed with (hence cache set) is in accord with the physical
	* address (i.e. tag). It's no different here. So I reckon we don't
	* need to flush the I-cache, since aliases don't matter for that. We
	* should try that.
	*
	* Caller takes mm->mmap_sem.
	*/
	void flush_cache_mm(struct mm_struct *mm)
	{
	/*
	* If cache is only 4k-per-way, there are never any 'aliases'. Since
	* the cache is physically tagged, the data can just be left in there.
	*/
	if (boot_cpu_data.dcache.n_aliases == 0)
	return;

	/*
	* Don't bother groveling around the dcache for the VMA ranges
	* if there are too many PTEs to make it worthwhile.
	*/
	if (mm->nr_ptes >= MAX_DCACHE_PAGES)
	flush_dcache_all();
	else {
	struct vm_area_struct *vma;

	/*
	* In this case there are reasonably sized ranges to flush,
	* iterate through the VMA list and take care of any aliases.
	*/
	for (vma = mm->mmap; vma; vma = vma->vm_next)
	__flush_cache_mm(mm, vma->vm_start, vma->vm_end);
	}

	/* Only touch the icache if one of the VMAs has VM_EXEC set. */
	if (mm->exec_vm)
	flush_icache_all();
	}

	/*
	* Write back and invalidate I/D-caches for the page.
	*
	* ADDR: Virtual Address (U0 address)
	* PFN: Physical page number
	*/
	void flush_cache_page(struct vm_area_struct *vma, unsigned long address,
	unsigned long pfn)
	{
	unsigned long phys = pfn << PAGE_SHIFT;
	unsigned int alias_mask;

	alias_mask = boot_cpu_data.dcache.alias_mask;

	/* We only need to flush D-cache when we have alias */
	if ((address^phys) & alias_mask) {
	/* Loop 4K of the D-cache */
	flush_cache_4096(
	CACHE_OC_ADDRESS_ARRAY \| (address & alias_mask),
	phys);
	/* Loop another 4K of the D-cache */
	flush_cache_4096(
	CACHE_OC_ADDRESS_ARRAY \| (phys & alias_mask),
	phys);
	}

	alias_mask = boot_cpu_data.icache.alias_mask;
	if (vma->vm_flags & VM_EXEC) {
	/*
	* Evict entries from the portion of the cache from which code
	* may have been executed at this address (virtual). There's
	* no need to evict from the portion corresponding to the
	* physical address as for the D-cache, because we know the
	* kernel has never executed the code through its identity
	* translation.
	*/
	flush_cache_4096(
	CACHE_IC_ADDRESS_ARRAY \| (address & alias_mask),
	phys);
	}
	}

	/*
	* Write back and invalidate D-caches.
	*
	* START, END: Virtual Address (U0 address)
	*
	* NOTE: We need to flush the _physical_ page entry.
	* Flushing the cache lines for U0 only isn't enough.
	* We need to flush for P1 too, which may contain aliases.
	*/
	void flush_cache_range(struct vm_area_struct *vma, unsigned long start,
	unsigned long end)
	{
	/*
	* If cache is only 4k-per-way, there are never any 'aliases'. Since
	* the cache is physically tagged, the data can just be left in there.
	*/
	if (boot_cpu_data.dcache.n_aliases == 0)
	return;

	/*
	* Don't bother with the lookup and alias check if we have a
	* wide range to cover, just blow away the dcache in its
	* entirety instead. -- PFM.
	*/
	if (((end - start) >> PAGE_SHIFT) >= MAX_DCACHE_PAGES)
	flush_dcache_all();
	else
	__flush_cache_mm(vma->vm_mm, start, end);

	if (vma->vm_flags & VM_EXEC) {
	/*
	* TODO: Is this required??? Need to look at how I-cache
	* coherency is assured when new programs are loaded to see if
	* this matters.
	*/
	flush_icache_all();
	}
	}

	/*
	* flush_icache_user_range
	* @vma: VMA of the process
	* @page: page
	* @addr: U0 address
	* @len: length of the range (< page size)
	*/
	void flush_icache_user_range(struct vm_area_struct *vma,
	struct page *page, unsigned long addr, int len)
	{
	flush_cache_page(vma, addr, page_to_pfn(page));
	mb();
	}

	/**
	* __flush_cache_4096
	*
	* @addr: address in memory mapped cache array
	* @phys: P1 address to flush (has to match tags if addr has 'A' bit
	* set i.e. associative write)
	* @exec_offset: set to 0x20000000 if flush has to be executed from P2
	* region else 0x0
	*
	* The offset into the cache array implied by 'addr' selects the
	* 'colour' of the virtual address range that will be flushed. The
	* operation (purge/write-back) is selected by the lower 2 bits of
	* 'phys'.
	*/
	static void __flush_cache_4096(unsigned long addr, unsigned long phys,
	unsigned long exec_offset)
	{
	int way_count;
	unsigned long base_addr = addr;
	struct cache_info *dcache;
	unsigned long way_incr;
	unsigned long a, ea, p;
	unsigned long temp_pc;

	dcache = &boot_cpu_data.dcache;
	/* Write this way for better assembly. */
	way_count = dcache->ways;
	way_incr = dcache->way_incr;

	/*
	* Apply exec_offset (i.e. branch to P2 if required.).
	*
	* FIXME:
	*
	* If I write "=r" for the (temp_pc), it puts this in r6 hence
	* trashing exec_offset before it's been added on - why? Hence
	* "=&r" as a 'workaround'
	*/
	asm volatile("mov.l 1f, %0\n\t"
	"add %1, %0\n\t"
	"jmp @%0\n\t"
	"nop\n\t"
	".balign 4\n\t"
	"1: .long 2f\n\t"
	"2:\n" : "=&r" (temp_pc) : "r" (exec_offset));

	/*
	* We know there will be >=1 iteration, so write as do-while to avoid
	* pointless nead-of-loop check for 0 iterations.
	*/
	do {
	ea = base_addr + PAGE_SIZE;
	a = base_addr;
	p = phys;

	do {
	(volatile unsigned long )a = p;
	/*
	* Next line: intentionally not p+32, saves an add, p
	* will do since only the cache tag bits need to
	* match.
	*/
	(volatile unsigned long )(a+32) = p;
	a += 64;
	p += 64;
	} while (a < ea);

	base_addr += way_incr;
	} while (--way_count != 0);
	}

	/*
	* Break the 1, 2 and 4 way variants of this out into separate functions to
	* avoid nearly all the overhead of having the conditional stuff in the function
	* bodies (+ the 1 and 2 way cases avoid saving any registers too).
	*/
	static void __flush_dcache_segment_1way(unsigned long start,
	unsigned long extent_per_way)
	{
	unsigned long orig_sr, sr_with_bl;
	unsigned long base_addr;
	unsigned long way_incr, linesz, way_size;
	struct cache_info *dcache;
	register unsigned long a0, a0e;

	asm volatile("stc sr, %0" : "=r" (orig_sr));
	sr_with_bl = orig_sr \| (1<<28);
	base_addr = ((unsigned long)&empty_zero_page[0]);

	/*
	* The previous code aligned base_addr to 16k, i.e. the way_size of all
	* existing SH-4 D-caches. Whilst I don't see a need to have this
	* aligned to any better than the cache line size (which it will be
	* anyway by construction), let's align it to at least the way_size of
	* any existing or conceivable SH-4 D-cache. -- RPC
	*/
	base_addr = ((base_addr >> 16) << 16);
	base_addr \|= start;

	dcache = &boot_cpu_data.dcache;
	linesz = dcache->linesz;
	way_incr = dcache->way_incr;
	way_size = dcache->way_size;

	a0 = base_addr;
	a0e = base_addr + extent_per_way;
	do {
	asm volatile("ldc %0, sr" : : "r" (sr_with_bl));
	asm volatile("movca.l r0, @%0\n\t"
	"ocbi @%0" : : "r" (a0));
	a0 += linesz;
	asm volatile("movca.l r0, @%0\n\t"
	"ocbi @%0" : : "r" (a0));
	a0 += linesz;
	asm volatile("movca.l r0, @%0\n\t"
	"ocbi @%0" : : "r" (a0));
	a0 += linesz;
	asm volatile("movca.l r0, @%0\n\t"
	"ocbi @%0" : : "r" (a0));
	asm volatile("ldc %0, sr" : : "r" (orig_sr));
	a0 += linesz;
	} while (a0 < a0e);
	}

	static void __flush_dcache_segment_2way(unsigned long start,
	unsigned long extent_per_way)
	{
	unsigned long orig_sr, sr_with_bl;
	unsigned long base_addr;
	unsigned long way_incr, linesz, way_size;
	struct cache_info *dcache;
	register unsigned long a0, a1, a0e;

	asm volatile("stc sr, %0" : "=r" (orig_sr));
	sr_with_bl = orig_sr \| (1<<28);
	base_addr = ((unsigned long)&empty_zero_page[0]);

	/* See comment under 1-way above */
	base_addr = ((base_addr >> 16) << 16);
	base_addr \|= start;

	dcache = &boot_cpu_data.dcache;
	linesz = dcache->linesz;
	way_incr = dcache->way_incr;
	way_size = dcache->way_size;

	a0 = base_addr;
	a1 = a0 + way_incr;
	a0e = base_addr + extent_per_way;
	do {
	asm volatile("ldc %0, sr" : : "r" (sr_with_bl));
	asm volatile("movca.l r0, @%0\n\t"
	"movca.l r0, @%1\n\t"
	"ocbi @%0\n\t"
	"ocbi @%1" : :
	"r" (a0), "r" (a1));
	a0 += linesz;
	a1 += linesz;
	asm volatile("movca.l r0, @%0\n\t"
	"movca.l r0, @%1\n\t"
	"ocbi @%0\n\t"
	"ocbi @%1" : :
	"r" (a0), "r" (a1));
	a0 += linesz;
	a1 += linesz;
	asm volatile("movca.l r0, @%0\n\t"
	"movca.l r0, @%1\n\t"
	"ocbi @%0\n\t"
	"ocbi @%1" : :
	"r" (a0), "r" (a1));
	a0 += linesz;
	a1 += linesz;
	asm volatile("movca.l r0, @%0\n\t"
	"movca.l r0, @%1\n\t"
	"ocbi @%0\n\t"
	"ocbi @%1" : :
	"r" (a0), "r" (a1));
	asm volatile("ldc %0, sr" : : "r" (orig_sr));
	a0 += linesz;
	a1 += linesz;
	} while (a0 < a0e);
	}

	static void __flush_dcache_segment_4way(unsigned long start,
	unsigned long extent_per_way)
	{
	unsigned long orig_sr, sr_with_bl;
	unsigned long base_addr;
	unsigned long way_incr, linesz, way_size;
	struct cache_info *dcache;
	register unsigned long a0, a1, a2, a3, a0e;

	asm volatile("stc sr, %0" : "=r" (orig_sr));
	sr_with_bl = orig_sr \| (1<<28);
	base_addr = ((unsigned long)&empty_zero_page[0]);

	/* See comment under 1-way above */
	base_addr = ((base_addr >> 16) << 16);
	base_addr \|= start;

	dcache = &boot_cpu_data.dcache;
	linesz = dcache->linesz;
	way_incr = dcache->way_incr;
	way_size = dcache->way_size;

	a0 = base_addr;
	a1 = a0 + way_incr;
	a2 = a1 + way_incr;
	a3 = a2 + way_incr;
	a0e = base_addr + extent_per_way;
	do {
	asm volatile("ldc %0, sr" : : "r" (sr_with_bl));
	asm volatile("movca.l r0, @%0\n\t"
	"movca.l r0, @%1\n\t"
	"movca.l r0, @%2\n\t"
	"movca.l r0, @%3\n\t"
	"ocbi @%0\n\t"
	"ocbi @%1\n\t"
	"ocbi @%2\n\t"
	"ocbi @%3\n\t" : :
	"r" (a0), "r" (a1), "r" (a2), "r" (a3));
	a0 += linesz;
	a1 += linesz;
	a2 += linesz;
	a3 += linesz;
	asm volatile("movca.l r0, @%0\n\t"
	"movca.l r0, @%1\n\t"
	"movca.l r0, @%2\n\t"
	"movca.l r0, @%3\n\t"
	"ocbi @%0\n\t"
	"ocbi @%1\n\t"
	"ocbi @%2\n\t"
	"ocbi @%3\n\t" : :
	"r" (a0), "r" (a1), "r" (a2), "r" (a3));
	a0 += linesz;
	a1 += linesz;
	a2 += linesz;
	a3 += linesz;
	asm volatile("movca.l r0, @%0\n\t"
	"movca.l r0, @%1\n\t"
	"movca.l r0, @%2\n\t"
	"movca.l r0, @%3\n\t"
	"ocbi @%0\n\t"
	"ocbi @%1\n\t"
	"ocbi @%2\n\t"
	"ocbi @%3\n\t" : :
	"r" (a0), "r" (a1), "r" (a2), "r" (a3));
	a0 += linesz;
	a1 += linesz;
	a2 += linesz;
	a3 += linesz;
	asm volatile("movca.l r0, @%0\n\t"
	"movca.l r0, @%1\n\t"
	"movca.l r0, @%2\n\t"
	"movca.l r0, @%3\n\t"
	"ocbi @%0\n\t"
	"ocbi @%1\n\t"
	"ocbi @%2\n\t"
	"ocbi @%3\n\t" : :
	"r" (a0), "r" (a1), "r" (a2), "r" (a3));
	asm volatile("ldc %0, sr" : : "r" (orig_sr));
	a0 += linesz;
	a1 += linesz;
	a2 += linesz;
	a3 += linesz;
	} while (a0 < a0e);
	}