powerpc: Move dma-noncoherent.c from arch/powerpc/lib to arch/powerpc/mm

(pre-requisite to make the next patches more palatable)

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 426 insertions, 0 deletions

diff --git a/arch/powerpc/mm/dma-noncoherent.c b/arch/powerpc/mm/dma-noncoherent.c
new file mode 100644
index 000000000000..b7dc4c19f582
--- /dev/null
+++ b/arch/powerpc/mm/dma-noncoherent.c
@@ -0,0 +1,426 @@
+/*
+ *  PowerPC version derived from arch/arm/mm/consistent.c
+ *    Copyright (C) 2001 Dan Malek (dmalek@jlc.net)
+ *
+ *  Copyright (C) 2000 Russell King
+ *
+ * Consistent memory allocators.  Used for DMA devices that want to
+ * share uncached memory with the processor core.  The function return
+ * is the virtual address and 'dma_handle' is the physical address.
+ * Mostly stolen from the ARM port, with some changes for PowerPC.
+ *                                              -- Dan
+ *
+ * Reorganized to get rid of the arch-specific consistent_* functions
+ * and provide non-coherent implementations for the DMA API. -Matt
+ *
+ * Added in_interrupt() safe dma_alloc_coherent()/dma_free_coherent()
+ * implementation. This is pulled straight from ARM and barely
+ * modified. -Matt
+ *
+ * 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/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/highmem.h>
+#include <linux/dma-mapping.h>
+
+#include <asm/tlbflush.h>
+
+/*
+ * This address range defaults to a value that is safe for all
+ * platforms which currently set CONFIG_NOT_COHERENT_CACHE. It
+ * can be further configured for specific applications under
+ * the "Advanced Setup" menu. -Matt
+ */
+#define CONSISTENT_BASE (CONFIG_CONSISTENT_START)
+#define CONSISTENT_END  (CONFIG_CONSISTENT_START + CONFIG_CONSISTENT_SIZE)
+#define CONSISTENT_OFFSET(x)    (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT)
+
+/*
+ * This is the page table (2MB) covering uncached, DMA consistent allocations
+ */
+static pte_t *consistent_pte;
+static DEFINE_SPINLOCK(consistent_lock);
+
+/*
+ * VM region handling support.
+ *
+ * This should become something generic, handling VM region allocations for
+ * vmalloc and similar (ioremap, module space, etc).
+ *
+ * I envisage vmalloc()'s supporting vm_struct becoming:
+ *
+ *  struct vm_struct {
+ *    struct vm_region  region;
+ *    unsigned long     flags;
+ *    struct page       **pages;
+ *    unsigned int      nr_pages;
+ *    unsigned long     phys_addr;
+ *  };
+ *
+ * get_vm_area() would then call vm_region_alloc with an appropriate
+ * struct vm_region head (eg):
+ *
+ *  struct vm_region vmalloc_head = {
+ *      .vm_list        = LIST_HEAD_INIT(vmalloc_head.vm_list),
+ *      .vm_start       = VMALLOC_START,
+ *      .vm_end         = VMALLOC_END,
+ *  };
+ *
+ * However, vmalloc_head.vm_start is variable (typically, it is dependent on
+ * the amount of RAM found at boot time.)  I would imagine that get_vm_area()
+ * would have to initialise this each time prior to calling vm_region_alloc().
+ */
+struct ppc_vm_region {
+        struct list_head        vm_list;
+        unsigned long           vm_start;
+        unsigned long           vm_end;
+};
+
+static struct ppc_vm_region consistent_head = {
+        .vm_list        = LIST_HEAD_INIT(consistent_head.vm_list),
+        .vm_start       = CONSISTENT_BASE,
+        .vm_end         = CONSISTENT_END,
+};
+
+static struct ppc_vm_region *
+ppc_vm_region_alloc(struct ppc_vm_region *head, size_t size, gfp_t gfp)
+{
+        unsigned long addr = head->vm_start, end = head->vm_end - size;
+        unsigned long flags;
+        struct ppc_vm_region *c, *new;
+
+        new = kmalloc(sizeof(struct ppc_vm_region), gfp);
+        if (!new)
+                goto out;
+
+        spin_lock_irqsave(&consistent_lock, flags);
+
+        list_for_each_entry(c, &head->vm_list, vm_list) {
+                if ((addr + size) < addr)
+                        goto nospc;
+                if ((addr + size) <= c->vm_start)
+                        goto found;
+                addr = c->vm_end;
+                if (addr > end)
+                        goto nospc;
+        }
+
+ found:
+        /*
+         * Insert this entry _before_ the one we found.
+         */
+        list_add_tail(&new->vm_list, &c->vm_list);
+        new->vm_start = addr;
+        new->vm_end = addr + size;
+
+        spin_unlock_irqrestore(&consistent_lock, flags);
+        return new;
+
+ nospc:
+        spin_unlock_irqrestore(&consistent_lock, flags);
+        kfree(new);
+ out:
+        return NULL;
+}
+
+static struct ppc_vm_region *ppc_vm_region_find(struct ppc_vm_region *head, unsigned long addr)
+{
+        struct ppc_vm_region *c;
+
+        list_for_each_entry(c, &head->vm_list, vm_list) {
+                if (c->vm_start == addr)
+                        goto out;
+        }
+        c = NULL;
+ out:
+        return c;
+}
+
+/*
+ * Allocate DMA-coherent memory space and return both the kernel remapped
+ * virtual and bus address for that space.
+ */
+void *
+__dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp)
+{
+        struct page *page;
+        struct ppc_vm_region *c;
+        unsigned long order;
+        u64 mask = 0x00ffffff, limit; /* ISA default */
+
+        if (!consistent_pte) {
+                printk(KERN_ERR "%s: not initialised\n", __func__);
+                dump_stack();
+                return NULL;
+        }
+
+        size = PAGE_ALIGN(size);
+        limit = (mask + 1) & ~mask;
+        if ((limit && size >= limit) || size >= (CONSISTENT_END - CONSISTENT_BASE)) {
+                printk(KERN_WARNING "coherent allocation too big (requested %#x mask %#Lx)\n",
+                       size, mask);
+                return NULL;
+        }
+
+        order = get_order(size);
+
+        if (mask != 0xffffffff)
+                gfp |= GFP_DMA;
+
+        page = alloc_pages(gfp, order);
+        if (!page)
+                goto no_page;
+
+        /*
+         * Invalidate any data that might be lurking in the
+         * kernel direct-mapped region for device DMA.
+         */
+        {
+                unsigned long kaddr = (unsigned long)page_address(page);
+                memset(page_address(page), 0, size);
+                flush_dcache_range(kaddr, kaddr + size);
+        }
+
+        /*
+         * Allocate a virtual address in the consistent mapping region.
+         */
+        c = ppc_vm_region_alloc(&consistent_head, size,
+                            gfp & ~(__GFP_DMA | __GFP_HIGHMEM));
+        if (c) {
+                unsigned long vaddr = c->vm_start;
+                pte_t *pte = consistent_pte + CONSISTENT_OFFSET(vaddr);
+                struct page *end = page + (1 << order);
+
+                split_page(page, order);
+
+                /*
+                 * Set the "dma handle"
+                 */
+                *handle = page_to_phys(page);
+
+                do {
+                        BUG_ON(!pte_none(*pte));
+
+                        SetPageReserved(page);
+                        set_pte_at(&init_mm, vaddr,
+                                   pte, mk_pte(page, pgprot_noncached(PAGE_KERNEL)));
+                        page++;
+                        pte++;
+                        vaddr += PAGE_SIZE;
+                } while (size -= PAGE_SIZE);
+
+                /*
+                 * Free the otherwise unused pages.
+                 */
+                while (page < end) {
+                        __free_page(page);
+                        page++;
+                }
+
+                return (void *)c->vm_start;
+        }
+
+        if (page)
+                __free_pages(page, order);
+ no_page:
+        return NULL;
+}
+EXPORT_SYMBOL(__dma_alloc_coherent);
+
+/*
+ * free a page as defined by the above mapping.
+ */
+void __dma_free_coherent(size_t size, void *vaddr)
+{
+        struct ppc_vm_region *c;
+        unsigned long flags, addr;
+        pte_t *ptep;
+
+        size = PAGE_ALIGN(size);
+
+        spin_lock_irqsave(&consistent_lock, flags);
+
+        c = ppc_vm_region_find(&consistent_head, (unsigned long)vaddr);
+        if (!c)
+                goto no_area;
+
+        if ((c->vm_end - c->vm_start) != size) {
+                printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
+                       __func__, c->vm_end - c->vm_start, size);
+                dump_stack();
+                size = c->vm_end - c->vm_start;
+        }
+
+        ptep = consistent_pte + CONSISTENT_OFFSET(c->vm_start);
+        addr = c->vm_start;
+        do {
+                pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep);
+                unsigned long pfn;
+
+                ptep++;
+                addr += PAGE_SIZE;
+
+                if (!pte_none(pte) && pte_present(pte)) {
+                        pfn = pte_pfn(pte);
+
+                        if (pfn_valid(pfn)) {
+                                struct page *page = pfn_to_page(pfn);
+                                ClearPageReserved(page);
+
+                                __free_page(page);
+                                continue;
+                        }
+                }
+
+                printk(KERN_CRIT "%s: bad page in kernel page table\n",
+                       __func__);
+        } while (size -= PAGE_SIZE);
+
+        flush_tlb_kernel_range(c->vm_start, c->vm_end);
+
+        list_del(&c->vm_list);
+
+        spin_unlock_irqrestore(&consistent_lock, flags);
+
+        kfree(c);
+        return;
+
+ no_area:
+        spin_unlock_irqrestore(&consistent_lock, flags);
+        printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n",
+               __func__, vaddr);
+        dump_stack();
+}
+EXPORT_SYMBOL(__dma_free_coherent);
+
+/*
+ * Initialise the consistent memory allocation.
+ */
+static int __init dma_alloc_init(void)
+{
+        pgd_t *pgd;
+        pud_t *pud;
+        pmd_t *pmd;
+        pte_t *pte;
+        int ret = 0;
+
+        do {
+                pgd = pgd_offset(&init_mm, CONSISTENT_BASE);
+                pud = pud_alloc(&init_mm, pgd, CONSISTENT_BASE);
+                pmd = pmd_alloc(&init_mm, pud, CONSISTENT_BASE);
+                if (!pmd) {
+                        printk(KERN_ERR "%s: no pmd tables\n", __func__);
+                        ret = -ENOMEM;
+                        break;
+                }
+
+                pte = pte_alloc_kernel(pmd, CONSISTENT_BASE);
+                if (!pte) {
+                        printk(KERN_ERR "%s: no pte tables\n", __func__);
+                        ret = -ENOMEM;
+                        break;
+                }
+
+                consistent_pte = pte;
+        } while (0);
+
+        return ret;
+}
+
+core_initcall(dma_alloc_init);
+
+/*
+ * make an area consistent.
+ */
+void __dma_sync(void *vaddr, size_t size, int direction)
+{
+        unsigned long start = (unsigned long)vaddr;
+        unsigned long end   = start + size;
+
+        switch (direction) {
+        case DMA_NONE:
+                BUG();
+        case DMA_FROM_DEVICE:
+                /*
+                 * invalidate only when cache-line aligned otherwise there is
+                 * the potential for discarding uncommitted data from the cache
+                 */
+                if ((start & (L1_CACHE_BYTES - 1)) || (size & (L1_CACHE_BYTES - 1)))
+                        flush_dcache_range(start, end);
+                else
+                        invalidate_dcache_range(start, end);
+                break;
+        case DMA_TO_DEVICE:             /* writeback only */
+                clean_dcache_range(start, end);
+                break;
+        case DMA_BIDIRECTIONAL: /* writeback and invalidate */
+                flush_dcache_range(start, end);
+                break;
+        }
+}
+EXPORT_SYMBOL(__dma_sync);
+
+#ifdef CONFIG_HIGHMEM
+/*
+ * __dma_sync_page() implementation for systems using highmem.
+ * In this case, each page of a buffer must be kmapped/kunmapped
+ * in order to have a virtual address for __dma_sync(). This must
+ * not sleep so kmap_atomic()/kunmap_atomic() are used.
+ *
+ * Note: yes, it is possible and correct to have a buffer extend
+ * beyond the first page.
+ */
+static inline void __dma_sync_page_highmem(struct page *page,
+                unsigned long offset, size_t size, int direction)
+{
+        size_t seg_size = min((size_t)(PAGE_SIZE - offset), size);
+        size_t cur_size = seg_size;
+        unsigned long flags, start, seg_offset = offset;
+        int nr_segs = 1 + ((size - seg_size) + PAGE_SIZE - 1)/PAGE_SIZE;
+        int seg_nr = 0;
+
+        local_irq_save(flags);
+
+        do {
+                start = (unsigned long)kmap_atomic(page + seg_nr,
+                                KM_PPC_SYNC_PAGE) + seg_offset;
+
+                /* Sync this buffer segment */
+                __dma_sync((void *)start, seg_size, direction);
+                kunmap_atomic((void *)start, KM_PPC_SYNC_PAGE);
+                seg_nr++;
+
+                /* Calculate next buffer segment size */
+                seg_size = min((size_t)PAGE_SIZE, size - cur_size);
+
+                /* Add the segment size to our running total */
+                cur_size += seg_size;
+                seg_offset = 0;
+        } while (seg_nr < nr_segs);
+
+        local_irq_restore(flags);
+}
+#endif /* CONFIG_HIGHMEM */
+
+/*
+ * __dma_sync_page makes memory consistent. identical to __dma_sync, but
+ * takes a struct page instead of a virtual address
+ */
+void __dma_sync_page(struct page *page, unsigned long offset,
+        size_t size, int direction)
+{
+#ifdef CONFIG_HIGHMEM
+        __dma_sync_page_highmem(page, offset, size, direction);
+#else
+        unsigned long start = (unsigned long)page_address(page) + offset;
+        __dma_sync((void *)start, size, direction);
+#endif
+}
+EXPORT_SYMBOL(__dma_sync_page);