linux/arch/arm/include/asm/dma-mapping.h

#ifndef ASMARM_DMA_MAPPING_H
#define ASMARM_DMA_MAPPING_H

#ifdef __KERNEL__

#include <linux/mm_types.h>
#include <linux/scatterlist.h>
#include <linux/dma-debug.h>

#include <asm/memory.h>

#include <xen/xen.h>
#include <asm/xen/hypervisor.h>

extern const struct dma_map_ops arm_dma_ops;
extern const struct dma_map_ops arm_coherent_dma_ops;

static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
{
	return IS_ENABLED(CONFIG_MMU) ? &arm_dma_ops : &dma_noop_ops;
}

#ifdef __arch_page_to_dma
#error Please update to __arch_pfn_to_dma
#endif

/*
 * dma_to_pfn/pfn_to_dma/dma_to_virt/virt_to_dma are architecture private
 * functions used internally by the DMA-mapping API to provide DMA
 * addresses. They must not be used by drivers.
 */
#ifndef __arch_pfn_to_dma
static inline dma_addr_t pfn_to_dma(struct device *dev, unsigned long pfn)
{
	if (dev)
		pfn -= dev->dma_pfn_offset;
	return (dma_addr_t)__pfn_to_bus(pfn);
}

static inline unsigned long dma_to_pfn(struct device *dev, dma_addr_t addr)
{
	unsigned long pfn = __bus_to_pfn(addr);

	if (dev)
		pfn += dev->dma_pfn_offset;

	return pfn;
}

static inline void *dma_to_virt(struct device *dev, dma_addr_t addr)
{
	if (dev) {
		unsigned long pfn = dma_to_pfn(dev, addr);

		return phys_to_virt(__pfn_to_phys(pfn));
	}

	return (void *)__bus_to_virt((unsigned long)addr);
}

static inline dma_addr_t virt_to_dma(struct device *dev, void *addr)
{
	if (dev)
		return pfn_to_dma(dev, virt_to_pfn(addr));

	return (dma_addr_t)__virt_to_bus((unsigned long)(addr));
}

#else
static inline dma_addr_t pfn_to_dma(struct device *dev, unsigned long pfn)
{
	return __arch_pfn_to_dma(dev, pfn);
}

static inline unsigned long dma_to_pfn(struct device *dev, dma_addr_t addr)
{
	return __arch_dma_to_pfn(dev, addr);
}

static inline void *dma_to_virt(struct device *dev, dma_addr_t addr)
{
	return __arch_dma_to_virt(dev, addr);
}

static inline dma_addr_t virt_to_dma(struct device *dev, void *addr)
{
	return __arch_virt_to_dma(dev, addr);
}
#endif

/* The ARM override for dma_max_pfn() */
static inline unsigned long dma_max_pfn(struct device *dev)
{
	return dma_to_pfn(dev, *dev->dma_mask);
}
#define dma_max_pfn(dev) dma_max_pfn(dev)

#define arch_setup_dma_ops arch_setup_dma_ops
extern void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
			       const struct iommu_ops *iommu, bool coherent);

#define arch_teardown_dma_ops arch_teardown_dma_ops
extern void arch_teardown_dma_ops(struct device *dev);

/* do not use this function in a driver */
static inline bool is_device_dma_coherent(struct device *dev)
{
	return dev->archdata.dma_coherent;
}

static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
{
	unsigned int offset = paddr & ~PAGE_MASK;
	return pfn_to_dma(dev, __phys_to_pfn(paddr)) + offset;
}

static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr)
{
	unsigned int offset = dev_addr & ~PAGE_MASK;
	return __pfn_to_phys(dma_to_pfn(dev, dev_addr)) + offset;
}

static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
{
	u64 limit, mask;

	if (!dev->dma_mask)
		return 0;

	mask = *dev->dma_mask;

	limit = (mask + 1) & ~mask;
	if (limit && size > limit)
		return 0;

	if ((addr | (addr + size - 1)) & ~mask)
		return 0;

	return 1;
}

static inline void dma_mark_clean(void *addr, size_t size) { }

/**
 * arm_dma_alloc - allocate consistent memory for DMA
 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 * @size: required memory size
 * @handle: bus-specific DMA address
 * @attrs: optinal attributes that specific mapping properties
 *
 * Allocate some memory for a device for performing DMA.  This function
 * allocates pages, and will return the CPU-viewed address, and sets @handle
 * to be the device-viewed address.
 */
extern void *arm_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
			   gfp_t gfp, unsigned long attrs);

/**
 * arm_dma_free - free memory allocated by arm_dma_alloc
 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 * @size: size of memory originally requested in dma_alloc_coherent
 * @cpu_addr: CPU-view address returned from dma_alloc_coherent
 * @handle: device-view address returned from dma_alloc_coherent
 * @attrs: optinal attributes that specific mapping properties
 *
 * Free (and unmap) a DMA buffer previously allocated by
 * arm_dma_alloc().
 *
 * References to memory and mappings associated with cpu_addr/handle
 * during and after this call executing are illegal.
 */
extern void arm_dma_free(struct device *dev, size_t size, void *cpu_addr,
			 dma_addr_t handle, unsigned long attrs);

/**
 * arm_dma_mmap - map a coherent DMA allocation into user space
 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 * @vma: vm_area_struct describing requested user mapping
 * @cpu_addr: kernel CPU-view address returned from dma_alloc_coherent
 * @handle: device-view address returned from dma_alloc_coherent
 * @size: size of memory originally requested in dma_alloc_coherent
 * @attrs: optinal attributes that specific mapping properties
 *
 * Map a coherent DMA buffer previously allocated by dma_alloc_coherent
 * into user space.  The coherent DMA buffer must not be freed by the
 * driver until the user space mapping has been released.
 */
extern int arm_dma_mmap(struct device *dev, struct vm_area_struct *vma,
			void *cpu_addr, dma_addr_t dma_addr, size_t size,
			unsigned long attrs);

/*
 * This can be called during early boot to increase the size of the atomic
 * coherent DMA pool above the default value of 256KiB. It must be called
 * before postcore_initcall.
 */
extern void __init init_dma_coherent_pool_size(unsigned long size);

/*
 * For SA-1111, IXP425, and ADI systems  the dma-mapping functions are "magic"
 * and utilize bounce buffers as needed to work around limited DMA windows.
 *
 * On the SA-1111, a bug limits DMA to only certain regions of RAM.
 * On the IXP425, the PCI inbound window is 64MB (256MB total RAM)
 * On some ADI engineering systems, PCI inbound window is 32MB (12MB total RAM)
 *
 * The following are helper functions used by the dmabounce subystem
 *
 */

/**
 * dmabounce_register_dev
 *
 * @dev: valid struct device pointer
 * @small_buf_size: size of buffers to use with small buffer pool
 * @large_buf_size: size of buffers to use with large buffer pool (can be 0)
 * @needs_bounce_fn: called to determine whether buffer needs bouncing
 *
 * This function should be called by low-level platform code to register
 * a device as requireing DMA buffer bouncing. The function will allocate
 * appropriate DMA pools for the device.
 */
extern int dmabounce_register_dev(struct device *, unsigned long,
		unsigned long, int (*)(struct device *, dma_addr_t, size_t));

/**
 * dmabounce_unregister_dev
 *
 * @dev: valid struct device pointer
 *
 * This function should be called by low-level platform code when device
 * that was previously registered with dmabounce_register_dev is removed
 * from the system.
 *
 */
extern void dmabounce_unregister_dev(struct device *);



/*
 * The scatter list versions of the above methods.
 */
extern int arm_dma_map_sg(struct device *, struct scatterlist *, int,
		enum dma_data_direction, unsigned long attrs);
extern void arm_dma_unmap_sg(struct device *, struct scatterlist *, int,
		enum dma_data_direction, unsigned long attrs);
extern void arm_dma_sync_sg_for_cpu(struct device *, struct scatterlist *, int,
		enum dma_data_direction);
extern void arm_dma_sync_sg_for_device(struct device *, struct scatterlist *, int,
		enum dma_data_direction);
extern int arm_dma_get_sgtable(struct device *dev, struct sg_table *sgt,
		void *cpu_addr, dma_addr_t dma_addr, size_t size,
		unsigned long attrs);

#endif /* __KERNEL__ */
#endif