microblaze: Add consistent code

Remove ancient Kconfig option for consistent code.
MMU uses cache inhibit pages.

noMMU uses UNCACHE SHADOW feature where is used double ram size.
For example:
Physical ram is 256MB and cache are setup to cover the same size.
But if you setup in HW that size is 512MB and cache covers 256MB
than you can use adresses from 256-512MB without caches and
correspond with 0-256MB with cache. That's why I am using
dcache base/high addresses to find out uncache area.

Signed-off-by: Michal Simek <monstr@monstr.eu>

3 files changed, 256 insertions, 1 deletions

diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig
index e451c0898e7..203ec61c6d4 100644
--- a/arch/microblaze/Kconfig
+++ b/arch/microblaze/Kconfig
@@ -156,6 +156,15 @@ config ADVANCED_OPTIONS
 comment "Default settings for advanced configuration options are used"
 	depends on !ADVANCED_OPTIONS
 
+config XILINX_UNCACHED_SHADOW
+	bool "Are you using uncached shadow for RAM ?"
+	depends on ADVANCED_OPTIONS && !MMU
+	default n
+	help
+	  This is needed to be able to allocate uncachable memory regions.
+	  The feature requires the design to define the RAM memory controller
+	  window to be twice as large as the actual physical memory.
+
 config HIGHMEM_START_BOOL
 	bool "Set high memory pool address"
 	depends on ADVANCED_OPTIONS && HIGHMEM
diff --git a/arch/microblaze/mm/Makefile b/arch/microblaze/mm/Makefile
index 6c8a924d9e2..09c49ed8723 100644
--- a/arch/microblaze/mm/Makefile
+++ b/arch/microblaze/mm/Makefile
@@ -2,6 +2,6 @@
 # Makefile
 #
 
-obj-y := init.o
+obj-y := consistent.o init.o
 
 obj-$(CONFIG_MMU) += pgtable.o mmu_context.o fault.o
diff --git a/arch/microblaze/mm/consistent.c b/arch/microblaze/mm/consistent.c
new file mode 100644
index 00000000000..a9b443e3fb9
--- /dev/null
+++ b/arch/microblaze/mm/consistent.c
@@ -0,0 +1,246 @@
+/*
+ * Microblaze support for cache consistent memory.
+ * Copyright (C) 2010 Michal Simek <monstr@monstr.eu>
+ * Copyright (C) 2010 PetaLogix
+ * Copyright (C) 2005 John Williams <jwilliams@itee.uq.edu.au>
+ *
+ * Based on PowerPC version derived from arch/arm/mm/consistent.c
+ * Copyright (C) 2001 Dan Malek (dmalek@jlc.net)
+ * Copyright (C) 2000 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/stddef.h>
+#include <linux/vmalloc.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/bootmem.h>
+#include <linux/highmem.h>
+#include <linux/pci.h>
+#include <linux/interrupt.h>
+
+#include <asm/pgalloc.h>
+#include <linux/io.h>
+#include <linux/hardirq.h>
+#include <asm/mmu_context.h>
+#include <asm/mmu.h>
+#include <linux/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/cpuinfo.h>
+
+#ifndef CONFIG_MMU
+
+/* I have to use dcache values because I can't relate on ram size */
+#define UNCACHED_SHADOW_MASK (cpuinfo.dcache_high - cpuinfo.dcache_base + 1)
+
+/*
+ * Consistent memory allocators. Used for DMA devices that want to
+ * share uncached memory with the processor core.
+ * My crufty no-MMU approach is simple. In the HW platform we can optionally
+ * mirror the DDR up above the processor cacheable region.  So, memory accessed
+ * in this mirror region will not be cached.  It's alloced from the same
+ * pool as normal memory, but the handle we return is shifted up into the
+ * uncached region.  This will no doubt cause big problems if memory allocated
+ * here is not also freed properly. -- JW
+ */
+void *consistent_alloc(int gfp, size_t size, dma_addr_t *dma_handle)
+{
+	struct page *page, *end, *free;
+	unsigned long order;
+	void *ret, *virt;
+
+	if (in_interrupt())
+		BUG();
+
+	size = PAGE_ALIGN(size);
+	order = get_order(size);
+
+	page = alloc_pages(gfp, order);
+	if (!page)
+		goto no_page;
+
+	/* We could do with a page_to_phys and page_to_bus here. */
+	virt = page_address(page);
+	ret = ioremap(virt_to_phys(virt), size);
+	if (!ret)
+		goto no_remap;
+
+	/*
+	 * Here's the magic!  Note if the uncached shadow is not implemented,
+	 * it's up to the calling code to also test that condition and make
+	 * other arranegments, such as manually flushing the cache and so on.
+	 */
+#ifdef CONFIG_XILINX_UNCACHED_SHADOW
+	ret = (void *)((unsigned) ret | UNCACHED_SHADOW_MASK);
+#endif
+	/* dma_handle is same as physical (shadowed) address */
+	*dma_handle = (dma_addr_t)ret;
+
+	/*
+	 * free wasted pages.  We skip the first page since we know
+	 * that it will have count = 1 and won't require freeing.
+	 * We also mark the pages in use as reserved so that
+	 * remap_page_range works.
+	 */
+	page = virt_to_page(virt);
+	free = page + (size >> PAGE_SHIFT);
+	end  = page + (1 << order);
+
+	for (; page < end; page++) {
+		init_page_count(page);
+		if (page >= free)
+			__free_page(page);
+		else
+			SetPageReserved(page);
+	}
+
+	return ret;
+no_remap:
+	__free_pages(page, order);
+no_page:
+	return NULL;
+}
+
+#else
+
+void *consistent_alloc(int gfp, size_t size, dma_addr_t *dma_handle)
+{
+	int order, err, i;
+	unsigned long page, va, flags;
+	phys_addr_t pa;
+	struct vm_struct *area;
+	void	 *ret;
+
+	if (in_interrupt())
+		BUG();
+
+	/* Only allocate page size areas. */
+	size = PAGE_ALIGN(size);
+	order = get_order(size);
+
+	page = __get_free_pages(gfp, order);
+	if (!page) {
+		BUG();
+		return NULL;
+	}
+
+	/*
+	 * we need to ensure that there are no cachelines in use,
+	 * or worse dirty in this area.
+	 */
+	flush_dcache_range(virt_to_phys(page), virt_to_phys(page) + size);
+
+	/* Allocate some common virtual space to map the new pages. */
+	area = get_vm_area(size, VM_ALLOC);
+	if (area == NULL) {
+		free_pages(page, order);
+		return NULL;
+	}
+	va = (unsigned long) area->addr;
+	ret = (void *)va;
+
+	/* This gives us the real physical address of the first page. */
+	*dma_handle = pa = virt_to_bus((void *)page);
+
+	/* MS: This is the whole magic - use cache inhibit pages */
+	flags = _PAGE_KERNEL | _PAGE_NO_CACHE;
+
+	/*
+	 * Set refcount=1 on all pages in an order>0
+	 * allocation so that vfree() will actually
+	 * free all pages that were allocated.
+	 */
+	if (order > 0) {
+		struct page *rpage = virt_to_page(page);
+		for (i = 1; i < (1 << order); i++)
+			init_page_count(rpage+i);
+	}
+
+	err = 0;
+	for (i = 0; i < size && err == 0; i += PAGE_SIZE)
+		err = map_page(va+i, pa+i, flags);
+
+	if (err) {
+		vfree((void *)va);
+		return NULL;
+	}
+
+	return ret;
+}
+#endif /* CONFIG_MMU */
+EXPORT_SYMBOL(consistent_alloc);
+
+/*
+ * free page(s) as defined by the above mapping.
+ */
+void consistent_free(void *vaddr)
+{
+	if (in_interrupt())
+		BUG();
+
+	/* Clear SHADOW_MASK bit in address, and free as per usual */
+#ifdef CONFIG_XILINX_UNCACHED_SHADOW
+	vaddr = (void *)((unsigned)vaddr & ~UNCACHED_SHADOW_MASK);
+#endif
+	vfree(vaddr);
+}
+EXPORT_SYMBOL(consistent_free);
+
+/*
+ * make an area consistent.
+ */
+void consistent_sync(void *vaddr, size_t size, int direction)
+{
+	unsigned long start;
+	unsigned long end;
+
+	start = (unsigned long)vaddr;
+
+	/* Convert start address back down to unshadowed memory region */
+#ifdef CONFIG_XILINX_UNCACHED_SHADOW
+	start &= ~UNCACHED_SHADOW_MASK;
+#endif
+	end = start + size;
+
+	switch (direction) {
+	case PCI_DMA_NONE:
+		BUG();
+	case PCI_DMA_FROMDEVICE:	/* invalidate only */
+		flush_dcache_range(start, end);
+		break;
+	case PCI_DMA_TODEVICE:		/* writeback only */
+		flush_dcache_range(start, end);
+		break;
+	case PCI_DMA_BIDIRECTIONAL:	/* writeback and invalidate */
+		flush_dcache_range(start, end);
+		break;
+	}
+}
+EXPORT_SYMBOL(consistent_sync);
+
+/*
+ * consistent_sync_page makes memory consistent. identical
+ * to consistent_sync, but takes a struct page instead of a
+ * virtual address
+ */
+void consistent_sync_page(struct page *page, unsigned long offset,
+	size_t size, int direction)
+{
+	unsigned long start = (unsigned long)page_address(page) + offset;
+	consistent_sync((void *)start, size, direction);
+}
+EXPORT_SYMBOL(consistent_sync_page);