metag: DMA

#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

/*

 *  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);