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Subject[PATCH v3 31/44] metag: DMA
Date
Add DMA mapping code.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
---
arch/metag/include/asm/dma-mapping.h | 183 ++++++++++++
arch/metag/kernel/dma.c | 507 ++++++++++++++++++++++++++++++++++
2 files changed, 690 insertions(+), 0 deletions(-)
create mode 100644 arch/metag/include/asm/dma-mapping.h
create mode 100644 arch/metag/kernel/dma.c

diff --git a/arch/metag/include/asm/dma-mapping.h b/arch/metag/include/asm/dma-mapping.h
new file mode 100644
index 0000000..b5f80a6
--- /dev/null
+++ b/arch/metag/include/asm/dma-mapping.h
@@ -0,0 +1,183 @@
+#ifndef _ASM_METAG_DMA_MAPPING_H
+#define _ASM_METAG_DMA_MAPPING_H
+
+#include <linux/mm.h>
+
+#include <asm/cache.h>
+#include <asm/io.h>
+#include <linux/scatterlist.h>
+#include <asm/bug.h>
+
+#define dma_alloc_noncoherent(d, s, h, f) dma_alloc_coherent(d, s, h, f)
+#define dma_free_noncoherent(d, s, v, h) dma_free_coherent(d, s, v, h)
+
+void *dma_alloc_coherent(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, gfp_t flag);
+
+void dma_free_coherent(struct device *dev, size_t size,
+ void *vaddr, dma_addr_t dma_handle);
+
+void dma_sync_for_device(void *vaddr, size_t size, int dma_direction);
+void dma_sync_for_cpu(void *vaddr, size_t size, int dma_direction);
+
+int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
+ void *cpu_addr, dma_addr_t dma_addr, size_t size);
+
+int dma_mmap_writecombine(struct device *dev, struct vm_area_struct *vma,
+ void *cpu_addr, dma_addr_t dma_addr, size_t size);
+
+static inline dma_addr_t
+dma_map_single(struct device *dev, void *ptr, size_t size,
+ enum dma_data_direction direction)
+{
+ BUG_ON(!valid_dma_direction(direction));
+ WARN_ON(size == 0);
+ dma_sync_for_device(ptr, size, direction);
+ return virt_to_phys(ptr);
+}
+
+static inline void
+dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
+ enum dma_data_direction direction)
+{
+ BUG_ON(!valid_dma_direction(direction));
+ dma_sync_for_cpu(phys_to_virt(dma_addr), size, direction);
+}
+
+static inline int
+dma_map_sg(struct device *dev, struct scatterlist *sglist, int nents,
+ enum dma_data_direction direction)
+{
+ struct scatterlist *sg;
+ int i;
+
+ BUG_ON(!valid_dma_direction(direction));
+ WARN_ON(nents == 0 || sglist[0].length == 0);
+
+ for_each_sg(sglist, sg, nents, i) {
+ BUG_ON(!sg_page(sg));
+
+ sg->dma_address = sg_phys(sg);
+ dma_sync_for_device(sg_virt(sg), sg->length, direction);
+ }
+
+ return nents;
+}
+
+static inline dma_addr_t
+dma_map_page(struct device *dev, struct page *page, unsigned long offset,
+ size_t size, enum dma_data_direction direction)
+{
+ BUG_ON(!valid_dma_direction(direction));
+ dma_sync_for_device((void *)(page_to_phys(page) + offset), size,
+ direction);
+ return page_to_phys(page) + offset;
+}
+
+static inline void
+dma_unmap_page(struct device *dev, dma_addr_t dma_address, size_t size,
+ enum dma_data_direction direction)
+{
+ BUG_ON(!valid_dma_direction(direction));
+ dma_sync_for_cpu(phys_to_virt(dma_address), size, direction);
+}
+
+
+static inline void
+dma_unmap_sg(struct device *dev, struct scatterlist *sglist, int nhwentries,
+ enum dma_data_direction direction)
+{
+ struct scatterlist *sg;
+ int i;
+
+ BUG_ON(!valid_dma_direction(direction));
+ WARN_ON(nhwentries == 0 || sglist[0].length == 0);
+
+ for_each_sg(sglist, sg, nhwentries, i) {
+ BUG_ON(!sg_page(sg));
+
+ sg->dma_address = sg_phys(sg);
+ dma_sync_for_cpu(sg_virt(sg), sg->length, direction);
+ }
+}
+
+static inline void
+dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle, size_t size,
+ enum dma_data_direction direction)
+{
+ dma_sync_for_cpu(phys_to_virt(dma_handle), size, direction);
+}
+
+static inline void
+dma_sync_single_for_device(struct device *dev, dma_addr_t dma_handle,
+ size_t size, enum dma_data_direction direction)
+{
+ dma_sync_for_device(phys_to_virt(dma_handle), size, direction);
+}
+
+static inline void
+dma_sync_single_range_for_cpu(struct device *dev, dma_addr_t dma_handle,
+ unsigned long offset, size_t size,
+ enum dma_data_direction direction)
+{
+ dma_sync_for_cpu(phys_to_virt(dma_handle)+offset, size,
+ direction);
+}
+
+static inline void
+dma_sync_single_range_for_device(struct device *dev, dma_addr_t dma_handle,
+ unsigned long offset, size_t size,
+ enum dma_data_direction direction)
+{
+ dma_sync_for_device(phys_to_virt(dma_handle)+offset, size,
+ direction);
+}
+
+static inline void
+dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nelems,
+ enum dma_data_direction direction)
+{
+ int i;
+ for (i = 0; i < nelems; i++, sg++)
+ dma_sync_for_cpu(sg_virt(sg), sg->length, direction);
+}
+
+static inline void
+dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nelems,
+ enum dma_data_direction direction)
+{
+ int i;
+ for (i = 0; i < nelems; i++, sg++)
+ dma_sync_for_device(sg_virt(sg), sg->length, direction);
+}
+
+static inline int
+dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
+{
+ return 0;
+}
+
+#define dma_supported(dev, mask) (1)
+
+static inline int
+dma_set_mask(struct device *dev, u64 mask)
+{
+ if (!dev->dma_mask || !dma_supported(dev, mask))
+ return -EIO;
+
+ *dev->dma_mask = mask;
+
+ return 0;
+}
+
+/*
+ * dma_alloc_noncoherent() returns non-cacheable memory, so there's no need to
+ * do any flushing here.
+ */
+static inline void
+dma_cache_sync(struct device *dev, void *vaddr, size_t size,
+ enum dma_data_direction direction)
+{
+}
+
+#endif
diff --git a/arch/metag/kernel/dma.c b/arch/metag/kernel/dma.c
new file mode 100644
index 0000000..8c00ded
--- /dev/null
+++ b/arch/metag/kernel/dma.c
@@ -0,0 +1,507 @@
+/*
+ * Meta version derived from arch/powerpc/lib/dma-noncoherent.c
+ * Copyright (C) 2008 Imagination Technologies Ltd.
+ *
+ * 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/export.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/highmem.h>
+#include <linux/dma-mapping.h>
+#include <linux/slab.h>
+
+#include <asm/tlbflush.h>
+#include <asm/mmu.h>
+
+#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_START) \
+ >> PAGE_SHIFT)
+
+static u64 get_coherent_dma_mask(struct device *dev)
+{
+ u64 mask = ~0ULL;
+
+ if (dev) {
+ mask = dev->coherent_dma_mask;
+
+ /*
+ * Sanity check the DMA mask - it must be non-zero, and
+ * must be able to be satisfied by a DMA allocation.
+ */
+ if (mask == 0) {
+ dev_warn(dev, "coherent DMA mask is unset\n");
+ return 0;
+ }
+ }
+
+ return mask;
+}
+/*
+ * 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 metag_vm_region region;
+ * unsigned long flags;
+ * struct page **pages;
+ * unsigned int nr_pages;
+ * unsigned long phys_addr;
+ * };
+ *
+ * get_vm_area() would then call metag_vm_region_alloc with an appropriate
+ * struct metag_vm_region head (eg):
+ *
+ * struct metag_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
+ * metag_vm_region_alloc().
+ */
+struct metag_vm_region {
+ struct list_head vm_list;
+ unsigned long vm_start;
+ unsigned long vm_end;
+ struct page *vm_pages;
+ int vm_active;
+};
+
+static struct metag_vm_region consistent_head = {
+ .vm_list = LIST_HEAD_INIT(consistent_head.vm_list),
+ .vm_start = CONSISTENT_START,
+ .vm_end = CONSISTENT_END,
+};
+
+static struct metag_vm_region *metag_vm_region_alloc(struct metag_vm_region
+ *head, size_t size,
+ gfp_t gfp)
+{
+ unsigned long addr = head->vm_start, end = head->vm_end - size;
+ unsigned long flags;
+ struct metag_vm_region *c, *new;
+
+ new = kmalloc(sizeof(struct metag_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;
+ new->vm_active = 1;
+
+ spin_unlock_irqrestore(&consistent_lock, flags);
+ return new;
+
+nospc:
+ spin_unlock_irqrestore(&consistent_lock, flags);
+ kfree(new);
+out:
+ return NULL;
+}
+
+static struct metag_vm_region *metag_vm_region_find(struct metag_vm_region
+ *head, unsigned long addr)
+{
+ struct metag_vm_region *c;
+
+ list_for_each_entry(c, &head->vm_list, vm_list) {
+ if (c->vm_active && 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(struct device *dev, size_t size,
+ dma_addr_t *handle, gfp_t gfp)
+{
+ struct page *page;
+ struct metag_vm_region *c;
+ unsigned long order;
+ u64 mask = get_coherent_dma_mask(dev);
+ u64 limit;
+
+ if (!consistent_pte) {
+ pr_err("%s: not initialised\n", __func__);
+ dump_stack();
+ return NULL;
+ }
+
+ if (!mask)
+ goto no_page;
+ size = PAGE_ALIGN(size);
+ limit = (mask + 1) & ~mask;
+ if ((limit && size >= limit)
+ || size >= (CONSISTENT_END - CONSISTENT_START)) {
+ pr_warn("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.
+ */
+ {
+ void *kaddr = page_address(page);
+ memset(kaddr, 0, size);
+ flush_dcache_region(kaddr, size);
+ }
+
+ /*
+ * Allocate a virtual address in the consistent mapping region.
+ */
+ c = metag_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);
+
+ c->vm_pages = page;
+ split_page(page, order);
+
+ /*
+ * Set the "dma handle"
+ */
+ *handle = page_to_bus(page);
+
+ do {
+ BUG_ON(!pte_none(*pte));
+
+ SetPageReserved(page);
+ set_pte_at(&init_mm, vaddr,
+ pte, mk_pte(page,
+ pgprot_writecombine
+ (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(struct device *dev, size_t size,
+ void *vaddr, dma_addr_t dma_handle)
+{
+ struct metag_vm_region *c;
+ unsigned long flags, addr;
+ pte_t *ptep;
+
+ size = PAGE_ALIGN(size);
+
+ spin_lock_irqsave(&consistent_lock, flags);
+
+ c = metag_vm_region_find(&consistent_head, (unsigned long)vaddr);
+ if (!c)
+ goto no_area;
+
+ c->vm_active = 0;
+ if ((c->vm_end - c->vm_start) != size) {
+ pr_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;
+ }
+ }
+
+ pr_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);
+ pr_err("%s: trying to free invalid coherent area: %p\n",
+ __func__, vaddr);
+ dump_stack();
+}
+EXPORT_SYMBOL(dma_free_coherent);
+
+
+static int dma_mmap(struct device *dev, struct vm_area_struct *vma,
+ void *cpu_addr, dma_addr_t dma_addr, size_t size)
+{
+ int ret = -ENXIO;
+
+ unsigned long flags, user_size, kern_size;
+ struct metag_vm_region *c;
+
+ user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+
+ spin_lock_irqsave(&consistent_lock, flags);
+ c = metag_vm_region_find(&consistent_head, (unsigned long)cpu_addr);
+ spin_unlock_irqrestore(&consistent_lock, flags);
+
+ if (c) {
+ unsigned long off = vma->vm_pgoff;
+
+ kern_size = (c->vm_end - c->vm_start) >> PAGE_SHIFT;
+
+ if (off < kern_size &&
+ user_size <= (kern_size - off)) {
+ ret = remap_pfn_range(vma, vma->vm_start,
+ page_to_pfn(c->vm_pages) + off,
+ user_size << PAGE_SHIFT,
+ vma->vm_page_prot);
+ }
+ }
+
+
+ return ret;
+}
+
+int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
+ void *cpu_addr, dma_addr_t dma_addr, size_t size)
+{
+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+ return dma_mmap(dev, vma, cpu_addr, dma_addr, size);
+}
+EXPORT_SYMBOL(dma_mmap_coherent);
+
+int dma_mmap_writecombine(struct device *dev, struct vm_area_struct *vma,
+ void *cpu_addr, dma_addr_t dma_addr, size_t size)
+{
+ vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
+ return dma_mmap(dev, vma, cpu_addr, dma_addr, size);
+}
+EXPORT_SYMBOL(dma_mmap_writecombine);
+
+
+
+
+/*
+ * Initialise the consistent memory allocation.
+ */
+static int __init dma_alloc_init(void)
+{
+ pgd_t *pgd, *pgd_k;
+ pud_t *pud, *pud_k;
+ pmd_t *pmd, *pmd_k;
+ pte_t *pte;
+ int ret = 0;
+
+ do {
+ int offset = pgd_index(CONSISTENT_START);
+ pgd = pgd_offset(&init_mm, CONSISTENT_START);
+ pud = pud_alloc(&init_mm, pgd, CONSISTENT_START);
+ pmd = pmd_alloc(&init_mm, pud, CONSISTENT_START);
+ if (!pmd) {
+ pr_err("%s: no pmd tables\n", __func__);
+ ret = -ENOMEM;
+ break;
+ }
+ WARN_ON(!pmd_none(*pmd));
+
+ pte = pte_alloc_kernel(pmd, CONSISTENT_START);
+ if (!pte) {
+ pr_err("%s: no pte tables\n", __func__);
+ ret = -ENOMEM;
+ break;
+ }
+
+ pgd_k = ((pgd_t *) mmu_get_base()) + offset;
+ pud_k = pud_offset(pgd_k, CONSISTENT_START);
+ pmd_k = pmd_offset(pud_k, CONSISTENT_START);
+ set_pmd(pmd_k, *pmd);
+
+ consistent_pte = pte;
+ } while (0);
+
+ return ret;
+}
+early_initcall(dma_alloc_init);
+
+/*
+ * make an area consistent to devices.
+ */
+void dma_sync_for_device(void *vaddr, size_t size, int dma_direction)
+{
+ /*
+ * Ensure any writes get through the write combiner. This is necessary
+ * even with DMA_FROM_DEVICE, or the write may dirty the cache after
+ * we've invalidated it and get written back during the DMA.
+ */
+
+ barrier();
+
+ switch (dma_direction) {
+ case DMA_BIDIRECTIONAL:
+ /*
+ * Writeback to ensure the device can see our latest changes and
+ * so that we have no dirty lines, and invalidate the cache
+ * lines too in preparation for receiving the buffer back
+ * (dma_sync_for_cpu) later.
+ */
+ flush_dcache_region(vaddr, size);
+ break;
+ case DMA_TO_DEVICE:
+ /*
+ * Writeback to ensure the device can see our latest changes.
+ * There's no need to invalidate as the device shouldn't write
+ * to the buffer.
+ */
+ writeback_dcache_region(vaddr, size);
+ break;
+ case DMA_FROM_DEVICE:
+ /*
+ * Invalidate to ensure we have no dirty lines that could get
+ * written back during the DMA. It's also safe to flush
+ * (writeback) here if necessary.
+ */
+ invalidate_dcache_region(vaddr, size);
+ break;
+ case DMA_NONE:
+ BUG();
+ }
+
+ wmb();
+}
+EXPORT_SYMBOL(dma_sync_for_device);
+
+/*
+ * make an area consistent to the core.
+ */
+void dma_sync_for_cpu(void *vaddr, size_t size, int dma_direction)
+{
+ /*
+ * Hardware L2 cache prefetch doesn't occur across 4K physical
+ * boundaries, however according to Documentation/DMA-API-HOWTO.txt
+ * kmalloc'd memory is DMA'able, so accesses in nearby memory could
+ * trigger a cache fill in the DMA buffer.
+ *
+ * This should never cause dirty lines, so a flush or invalidate should
+ * be safe to allow us to see data from the device.
+ */
+ if (_meta_l2c_pf_is_enabled()) {
+ switch (dma_direction) {
+ case DMA_BIDIRECTIONAL:
+ case DMA_FROM_DEVICE:
+ invalidate_dcache_region(vaddr, size);
+ break;
+ case DMA_TO_DEVICE:
+ /* The device shouldn't have written to the buffer */
+ break;
+ case DMA_NONE:
+ BUG();
+ }
+ }
+
+ rmb();
+}
+EXPORT_SYMBOL(dma_sync_for_cpu);
--
1.7.7.6



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