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Subject[PATCH 07/19] OpenRISC: DMA
Date

Simple DMA implementation. There's some work to do here, but
this allows for allocation of coherent memory (simply uncached) for DMA
operations.

Signed-off-by: Jonas Bonn <jonas@southpole.se>
---
arch/openrisc/include/asm/dma-mapping.h | 129 ++++++++++++++++++++++++++
arch/openrisc/kernel/dma.c | 152 +++++++++++++++++++++++++++++++
2 files changed, 281 insertions(+), 0 deletions(-)
create mode 100644 arch/openrisc/include/asm/dma-mapping.h
create mode 100644 arch/openrisc/kernel/dma.c
diff --git a/arch/openrisc/include/asm/dma-mapping.h b/arch/openrisc/include/asm/dma-mapping.h
new file mode 100644
index 0000000..10066f4
--- /dev/null
+++ b/arch/openrisc/include/asm/dma-mapping.h
@@ -0,0 +1,129 @@
+/*
+ * OpenRISC Linux
+ *
+ * Linux architectural port borrowing liberally from similar works of
+ * others. All original copyrights apply as per the original source
+ * declaration.
+ *
+ * OpenRISC implementation:
+ * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
+ * et al.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef __ASM_OPENRISC_DMA_MAPPING_H
+#define __ASM_OPENRISC_DMA_MAPPING_H
+
+/*
+ * See Documentation/PCI/PCI-DMA-mapping.txt and
+ * Documentation/DMA-API.txt for documentation.
+ */
+
+#include <linux/types.h>
+#include <linux/cache.h>
+#include <linux/mm.h>
+#include <linux/scatterlist.h>
+#include <linux/dma-debug.h>
+#include <linux/dma-attrs.h>
+#include <asm/io.h>
+#include <asm-generic/dma-coherent.h>
+
+#define DMA_ERROR_CODE (~(dma_addr_t)0x0)
+
+static inline unsigned long device_to_mask(struct device *dev)
+{
+ if (dev->dma_mask && *dev->dma_mask)
+ return *dev->dma_mask;
+ /* Assume devices without mask can take 32 bit addresses */
+ return 0xfffffffful;
+}
+
+extern struct dma_map_ops or1k_dma_ops;
+
+static inline struct dma_map_ops* get_dma_ops(struct device *dev)
+{
+ return &or1k_dma_ops;
+/*#else
+ if (unlikely(!dev) || !dev->archdata.dma_ops)
+ return dma_ops;
+ else
+ return dev->archdata.dma_ops;
+#endif
+*/
+}
+
+#include <asm-generic/dma-mapping-common.h>
+
+/*
+static inline void set_dma_ops(struct device *dev, struct dma_map_ops *ops)
+{
+ dev->archdata.dma_ops = ops;
+}
+*/
+
+static inline int
+dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
+{
+ return 0;
+}
+
+static inline int
+dma_supported(struct device *dev, u64 mask)
+{
+ return 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;
+}
+
+#if 0
+static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
+{
+ struct dma_map_ops *ops = get_dma_ops(dev);
+ if (ops->mapping_error)
+ return ops->mapping_error(dev, dma_addr);
+
+ return (dma_addr == DMA_ERROR_CODE);
+}
+#endif
+
+#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)
+
+static inline void *dma_alloc_coherent(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, gfp_t flag)
+{
+ struct dma_map_ops *ops = get_dma_ops(dev);
+ void *memory;
+
+ BUG_ON(!ops);
+
+ memory = ops->alloc_coherent(dev, size, dma_handle, flag);
+
+ debug_dma_alloc_coherent(dev, size, *dma_handle, memory);
+ return memory;
+}
+
+static inline void dma_free_coherent(struct device *dev, size_t size,
+ void *cpu_addr, dma_addr_t dma_handle)
+{
+ struct dma_map_ops *ops = get_dma_ops(dev);
+
+ BUG_ON(!ops);
+ debug_dma_free_coherent(dev, size, cpu_addr, dma_handle);
+ ops->free_coherent(dev, size, cpu_addr, dma_handle);
+}
+
+#endif /* __ASM_OPENRISC_DMA_MAPPING_H */
diff --git a/arch/openrisc/kernel/dma.c b/arch/openrisc/kernel/dma.c
new file mode 100644
index 0000000..3c813a0
--- /dev/null
+++ b/arch/openrisc/kernel/dma.c
@@ -0,0 +1,152 @@
+/*
+ * OpenRISC dma.c
+ *
+ * Linux architectural port borrowing liberally from similar works of
+ * others. All original copyrights apply as per the original source
+ * declaration.
+ *
+ * Modifications for the OpenRISC architecture:
+ * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
+ * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * DMA mapping callbacks...
+ * As alloc_coherent is the only DMA callback being used currently, that's
+ * the only thing implemented properly. The rest need looking into...
+ */
+
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/gfp.h>
+#include <linux/dma-debug.h>
+#include <linux/io.h>
+#include <linux/vmalloc.h>
+#include <asm/bug.h>
+
+/*
+ * Alloc "coherent" memory, which for OpenRISC means simply uncached.
+ */
+static void*
+or1k_dma_alloc_coherent(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, gfp_t flag)
+{
+ int order;
+ unsigned long page, va;
+ pgprot_t prot;
+ struct vm_struct *area;
+
+ /* Only allocate page size areas. */
+ size = PAGE_ALIGN(size);
+ order = get_order(size);
+
+ page = __get_free_pages(flag, order);
+ if (!page) {
+ return NULL;
+ }
+
+ /* 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;
+
+ /* This gives us the real physical address of the first page. */
+ //*dma_handle = __pa(page);
+
+ prot = PAGE_KERNEL_NOCACHE;
+
+ /* This isn't so much ioremap as just simply 'remap' */
+ if (ioremap_page_range(va, va + size, page, prot)) {
+ vfree(area->addr);
+ return NULL;
+ }
+
+ *dma_handle = page;
+ return (void*) va;
+}
+
+static void
+or1k_dma_free_coherent(struct device* dev, size_t size, void* vaddr,
+ dma_addr_t dma_handle)
+{
+ vfree(vaddr);
+}
+
+static int
+or1k_dma_map_sg(struct device *dev, struct scatterlist *sgl,
+ int nents, enum dma_data_direction direction,
+ struct dma_attrs *attrs)
+{
+ struct scatterlist *sg;
+ int i;
+
+ BUG();
+ return 0;
+#if 0
+ /* FIXME this part of code is untested */
+ for_each_sg(sgl, sg, nents, i) {
+ sg->dma_address = sg_phys(sg);
+ __dma_sync_page(page_to_phys(sg_page(sg)), sg->offset,
+ sg->length, direction);
+ }
+
+ return nents;
+#endif
+}
+
+static inline dma_addr_t
+or1k_dma_map_page(struct device *dev,
+ struct page *page,
+ unsigned long offset,
+ size_t size,
+ enum dma_data_direction direction,
+ struct dma_attrs *attrs)
+{
+ BUG();
+ return NULL;
+}
+
+#if 0
+static void
+__dma_map_range(dma_addr_t dma_addr, size_t size)
+{
+ struct page *page = pfn_to_page(PFN_DOWN(dma_addr));
+ size_t bytesleft = PAGE_SIZE - (dma_addr & (PAGE_SIZE - 1));
+
+ while ((ssize_t)size > 0) {
+ /* Flush the page. */
+
+ homecache_flush_cache(page++, 0);
+
+ /* Figure out if we need to continue on the next page. */
+ size -= bytesleft;
+ bytesleft = PAGE_SIZE;
+ }
+cacheflush(...);
+}
+#endif
+
+struct dma_map_ops or1k_dma_ops = {
+ .alloc_coherent = or1k_dma_alloc_coherent,
+ .free_coherent = or1k_dma_free_coherent,
+ .map_sg = or1k_dma_map_sg,
+ .map_page = or1k_dma_map_page,
+};
+EXPORT_SYMBOL(or1k_dma_ops);
+
+/* Number of entries preallocated for DMA-API debugging */
+#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
+
+static int __init dma_init(void)
+{
+ dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
+
+ return 0;
+}
+fs_initcall(dma_init);
--
1.7.4.1


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