/*
   * arch/sh/mm/cache-sh4.c
   *
   * Copyright (C) 1999, 2000, 2002  Niibe Yutaka
   * Copyright (C) 2001 - 2009  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 <linux/highmem.h>
  #include <asm/pgtable.h>
  #include <asm/mmu_context.h>
  #include <asm/cache_insns.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_ICACHE_PAGES	32
  
  static void __flush_cache_one(unsigned long addr, unsigned long phys,
  			       unsigned long exec_offset);
  
  /*
   * 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
   */
  static void sh4_flush_icache_range(void *args)
  {
  	struct flusher_data *data = args;
  	unsigned long start, end;
  	unsigned long flags, v;
  	int i;
  
  	start = data->addr1;
  	end = data->addr2;
  
  	/* If there are too many pages then just blow away the caches */
  	if (((end - start) >> PAGE_SHIFT) >= MAX_ICACHE_PAGES) {
  		local_flush_cache_all(NULL);
  		return;
  	}
  
  	/*
  	 * Selectively flush d-cache then invalidate the i-cache.
  	 * This is inefficient, so only use this 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) {
  		unsigned long icacheaddr;
  		int j, n;
  
  		__ocbwb(v);
  
  		icacheaddr = CACHE_IC_ADDRESS_ARRAY | (v &
  				cpu_data->icache.entry_mask);
  
  		/* Clear i-cache line valid-bit */
  		n = boot_cpu_data.icache.n_aliases;
  		for (i = 0; i < cpu_data->icache.ways; i++) {
  			for (j = 0; j < n; j++)
  				__raw_writel(0, icacheaddr + (j * PAGE_SIZE));
  			icacheaddr += cpu_data->icache.way_incr;
  		}
  	}
  
  	back_to_cached();
  	local_irq_restore(flags);
  }
  
  static inline void flush_cache_one(unsigned long start, unsigned long phys)
  {
  	unsigned long flags, exec_offset = 0;
  
  	/*
  	 * All types of SH-4 require PC to be uncached to operate on the I-cache.
  	 * Some types of SH-4 require PC to be uncached to operate on the D-cache.
  	 */
  	if ((boot_cpu_data.flags & CPU_HAS_P2_FLUSH_BUG) ||
  	    (start < CACHE_OC_ADDRESS_ARRAY))
  		exec_offset = cached_to_uncached;
  
  	local_irq_save(flags);
  	__flush_cache_one(start, phys, exec_offset);
  	local_irq_restore(flags);
  }
  
  /*
   * Write back & invalidate the D-cache of the page.
   * (To avoid "alias" issues)
   */
  static void sh4_flush_dcache_page(void *arg)
  {
  	struct page *page = arg;
  	unsigned long addr = (unsigned long)page_address(page);
  #ifndef CONFIG_SMP
  	struct address_space *mapping = page_mapping(page);
  
  	if (mapping && !mapping_mapped(mapping))
  		clear_bit(PG_dcache_clean, &page->flags);
  	else
  #endif
  		flush_cache_one(CACHE_OC_ADDRESS_ARRAY |
  				(addr & shm_align_mask), page_to_phys(page));
  
  	wmb();
  }
  
  /* TODO: Selective icache invalidation through IC address array.. */
  static void flush_icache_all(void)
  {
  	unsigned long flags, ccr;
  
  	local_irq_save(flags);
  	jump_to_uncached();
  
  	/* Flush I-cache */
  	ccr = __raw_readl(SH_CCR);
  	ccr |= CCR_CACHE_ICI;
  	__raw_writel(ccr, SH_CCR);
  
  	/*
  	 * back_to_cached() will take care of the barrier for us, don't add
  	 * another one!
  	 */
  
  	back_to_cached();
  	local_irq_restore(flags);
  }
  
  static void flush_dcache_all(void)
  {
  	unsigned long addr, end_addr, entry_offset;
  
  	end_addr = CACHE_OC_ADDRESS_ARRAY +
  		(current_cpu_data.dcache.sets <<
  		 current_cpu_data.dcache.entry_shift) *
  			current_cpu_data.dcache.ways;
  
  	entry_offset = 1 << current_cpu_data.dcache.entry_shift;
  
  	for (addr = CACHE_OC_ADDRESS_ARRAY; addr < end_addr; ) {
  		__raw_writel(0, addr); addr += entry_offset;
  		__raw_writel(0, addr); addr += entry_offset;
  		__raw_writel(0, addr); addr += entry_offset;
  		__raw_writel(0, addr); addr += entry_offset;
  		__raw_writel(0, addr); addr += entry_offset;
  		__raw_writel(0, addr); addr += entry_offset;
  		__raw_writel(0, addr); addr += entry_offset;
  		__raw_writel(0, addr); addr += entry_offset;
  	}
  }
  
  static void sh4_flush_cache_all(void *unused)
  {
  	flush_dcache_all();
  	flush_icache_all();
  }
  
  /*
   * 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.
   *
   * Caller takes mm->mmap_sem.
   */
  static void sh4_flush_cache_mm(void *arg)
  {
  	struct mm_struct *mm = arg;
  
  	if (cpu_context(smp_processor_id(), mm) == NO_CONTEXT)
  		return;
  
  	flush_dcache_all();
  }
  
  /*
   * Write back and invalidate I/D-caches for the page.
   *
   * ADDR: Virtual Address (U0 address)
   * PFN: Physical page number
   */
  static void sh4_flush_cache_page(void *args)
  {
  	struct flusher_data *data = args;
  	struct vm_area_struct *vma;
  	struct page *page;
  	unsigned long address, pfn, phys;
  	int map_coherent = 0;
  	pgd_t *pgd;
  	pud_t *pud;
  	pmd_t *pmd;
  	pte_t *pte;
  	void *vaddr;
  
  	vma = data->vma;
  	address = data->addr1 & PAGE_MASK;
  	pfn = data->addr2;
  	phys = pfn << PAGE_SHIFT;
  	page = pfn_to_page(pfn);
  
  	if (cpu_context(smp_processor_id(), vma->vm_mm) == NO_CONTEXT)
  		return;
  
  	pgd = pgd_offset(vma->vm_mm, address);
  	pud = pud_offset(pgd, address);
  	pmd = pmd_offset(pud, address);
  	pte = pte_offset_kernel(pmd, address);
  
  	/* If the page isn't present, there is nothing to do here. */
  	if (!(pte_val(*pte) & _PAGE_PRESENT))
  		return;
  
  	if ((vma->vm_mm == current->active_mm))
  		vaddr = NULL;
  	else {
  		/*
  		 * Use kmap_coherent or kmap_atomic to do flushes for
  		 * another ASID than the current one.
  		 */
  		map_coherent = (current_cpu_data.dcache.n_aliases &&
  			test_bit(PG_dcache_clean, &page->flags) &&
  			page_mapped(page));
  		if (map_coherent)
  			vaddr = kmap_coherent(page, address);
  		else
  			vaddr = kmap_atomic(page);
  
  		address = (unsigned long)vaddr;
  	}
  
  	flush_cache_one(CACHE_OC_ADDRESS_ARRAY |
  			(address & shm_align_mask), phys);
  
  	if (vma->vm_flags & VM_EXEC)
  		flush_icache_all();
  
  	if (vaddr) {
  		if (map_coherent)
  			kunmap_coherent(vaddr);
  		else
  			kunmap_atomic(vaddr);
  	}
  }
  
  /*
   * 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.
   */
  static void sh4_flush_cache_range(void *args)
  {
  	struct flusher_data *data = args;
  	struct vm_area_struct *vma;
  	unsigned long start, end;
  
  	vma = data->vma;
  	start = data->addr1;
  	end = data->addr2;
  
  	if (cpu_context(smp_processor_id(), vma->vm_mm) == NO_CONTEXT)
  		return;
  
  	/*
  	 * 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;
  
  	flush_dcache_all();
  
  	if (vma->vm_flags & VM_EXEC)
  		flush_icache_all();
  }
  
  /**
   * __flush_cache_one
   *
   * @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_one(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
  \t"
  		     "add   %1, %0
  \t"
  		     "jmp   @%0
  \t"
  		     "nop
  \t"
  		     ".balign 4
  \t"
  		     "1:  .long 2f
  \t"
  		     "2:
  " : "=&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);
  }
  
  extern void __weak sh4__flush_region_init(void);
  
  /*
   * SH-4 has virtually indexed and physically tagged cache.
   */
  void __init sh4_cache_init(void)
  {
  	printk("PVR=%08x CVR=%08x PRR=%08x
  ",
  		__raw_readl(CCN_PVR),
  		__raw_readl(CCN_CVR),
  		__raw_readl(CCN_PRR));
  
  	local_flush_icache_range	= sh4_flush_icache_range;
  	local_flush_dcache_page		= sh4_flush_dcache_page;
  	local_flush_cache_all		= sh4_flush_cache_all;
  	local_flush_cache_mm		= sh4_flush_cache_mm;
  	local_flush_cache_dup_mm	= sh4_flush_cache_mm;
  	local_flush_cache_page		= sh4_flush_cache_page;
  	local_flush_cache_range		= sh4_flush_cache_range;
  
  	sh4__flush_region_init();
  }