3 files changed, 256 insertions, 1 deletions

diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig
index e451c0898e7a..203ec61c6d4c 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 6c8a924d9e26..09c49ed87235 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 000000000000..a9b443e3fb98
--- /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);