[mirror_ubuntu-focal-kernel.git] / arch / arm / xen / mm.c

#include <linux/cpu.h>
#include <linux/dma-mapping.h>
#include <linux/gfp.h>
#include <linux/highmem.h>
#include <linux/export.h>
#include <linux/memblock.h>
#include <linux/of_address.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/vmalloc.h>
#include <linux/swiotlb.h>

#include <xen/xen.h>
#include <xen/interface/grant_table.h>
#include <xen/interface/memory.h>
#include <xen/page.h>
#include <xen/swiotlb-xen.h>

#include <asm/cacheflush.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/interface.h>

unsigned long xen_get_swiotlb_free_pages(unsigned int order)
{
	struct memblock_region *reg;
	gfp_t flags = __GFP_NOWARN|__GFP_KSWAPD_RECLAIM;

	for_each_memblock(memory, reg) {
		if (reg->base < (phys_addr_t)0xffffffff) {
			flags |= __GFP_DMA;
			break;
		}
	}
	return __get_free_pages(flags, order);
}

enum dma_cache_op {
       DMA_UNMAP,
       DMA_MAP,
};
static bool hypercall_cflush = false;

/* functions called by SWIOTLB */

static void dma_cache_maint(dma_addr_t handle, unsigned long offset,
	size_t size, enum dma_data_direction dir, enum dma_cache_op op)
{
	struct gnttab_cache_flush cflush;
	unsigned long xen_pfn;
	size_t left = size;

	xen_pfn = (handle >> XEN_PAGE_SHIFT) + offset / XEN_PAGE_SIZE;
	offset %= XEN_PAGE_SIZE;

	do {
		size_t len = left;
	
		/* buffers in highmem or foreign pages cannot cross page
		 * boundaries */
		if (len + offset > XEN_PAGE_SIZE)
			len = XEN_PAGE_SIZE - offset;

		cflush.op = 0;
		cflush.a.dev_bus_addr = xen_pfn << XEN_PAGE_SHIFT;
		cflush.offset = offset;
		cflush.length = len;

		if (op == DMA_UNMAP && dir != DMA_TO_DEVICE)
			cflush.op = GNTTAB_CACHE_INVAL;
		if (op == DMA_MAP) {
			if (dir == DMA_FROM_DEVICE)
				cflush.op = GNTTAB_CACHE_INVAL;
			else
				cflush.op = GNTTAB_CACHE_CLEAN;
		}
		if (cflush.op)
			HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1);

		offset = 0;
		xen_pfn++;
		left -= len;
	} while (left);
}

static void __xen_dma_page_dev_to_cpu(struct device *hwdev, dma_addr_t handle,
		size_t size, enum dma_data_direction dir)
{
	dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, DMA_UNMAP);
}

static void __xen_dma_page_cpu_to_dev(struct device *hwdev, dma_addr_t handle,
		size_t size, enum dma_data_direction dir)
{
	dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, DMA_MAP);
}

void __xen_dma_map_page(struct device *hwdev, struct page *page,
	     dma_addr_t dev_addr, unsigned long offset, size_t size,
	     enum dma_data_direction dir, unsigned long attrs)
{
	if (is_device_dma_coherent(hwdev))
		return;
	if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
		return;

	__xen_dma_page_cpu_to_dev(hwdev, dev_addr, size, dir);
}

void __xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,
		size_t size, enum dma_data_direction dir,
		unsigned long attrs)

{
	if (is_device_dma_coherent(hwdev))
		return;
	if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
		return;

	__xen_dma_page_dev_to_cpu(hwdev, handle, size, dir);
}

void __xen_dma_sync_single_for_cpu(struct device *hwdev,
		dma_addr_t handle, size_t size, enum dma_data_direction dir)
{
	if (is_device_dma_coherent(hwdev))
		return;
	__xen_dma_page_dev_to_cpu(hwdev, handle, size, dir);
}

void __xen_dma_sync_single_for_device(struct device *hwdev,
		dma_addr_t handle, size_t size, enum dma_data_direction dir)
{
	if (is_device_dma_coherent(hwdev))
		return;
	__xen_dma_page_cpu_to_dev(hwdev, handle, size, dir);
}

bool xen_arch_need_swiotlb(struct device *dev,
			   phys_addr_t phys,
			   dma_addr_t dev_addr)
{
	unsigned int xen_pfn = XEN_PFN_DOWN(phys);
	unsigned int bfn = XEN_PFN_DOWN(dev_addr);

	/*
	 * The swiotlb buffer should be used if
	 *	- Xen doesn't have the cache flush hypercall
	 *	- The Linux page refers to foreign memory
	 *	- The device doesn't support coherent DMA request
	 *
	 * The Linux page may be spanned acrros multiple Xen page, although
	 * it's not possible to have a mix of local and foreign Xen page.
	 * Furthermore, range_straddles_page_boundary is already checking
	 * if buffer is physically contiguous in the host RAM.
	 *
	 * Therefore we only need to check the first Xen page to know if we
	 * require a bounce buffer because the device doesn't support coherent
	 * memory and we are not able to flush the cache.
	 */
	return (!hypercall_cflush && (xen_pfn != bfn) &&
		!is_device_dma_coherent(dev));
}

int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
				 unsigned int address_bits,
				 dma_addr_t *dma_handle)
{
	if (!xen_initial_domain())
		return -EINVAL;

	/* we assume that dom0 is mapped 1:1 for now */
	*dma_handle = pstart;
	return 0;
}
EXPORT_SYMBOL_GPL(xen_create_contiguous_region);

void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
{
	return;
}
EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);

const struct dma_map_ops *xen_dma_ops;
EXPORT_SYMBOL(xen_dma_ops);

int __init xen_mm_init(void)
{
	struct gnttab_cache_flush cflush;
	if (!xen_initial_domain())
		return 0;
	xen_swiotlb_init(1, false);
	xen_dma_ops = &xen_swiotlb_dma_ops;

	cflush.op = 0;
	cflush.a.dev_bus_addr = 0;
	cflush.offset = 0;
	cflush.length = 0;
	if (HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1) != -ENOSYS)
		hypercall_cflush = true;
	return 0;
}
arch_initcall(xen_mm_init);
Commit	Line	Data
5121872a SS	1	#include <linux/cpu.h>
5121872a SS	2	#include <linux/dma-mapping.h>
83862ccf	3	#include <linux/gfp.h>
5121872a	4	#include <linux/highmem.h>
83862ccf	5	#include <linux/export.h>
8746515d	6	#include <linux/memblock.h>
5121872a	7	#include <linux/of_address.h>
83862ccf SS	8	#include <linux/slab.h>
83862ccf SS	9	#include <linux/types.h>
83862ccf SS	10	#include <linux/vmalloc.h>
	11	#include <linux/swiotlb.h>
	12
	13	#include <xen/xen.h>
da095a99	14	#include <xen/interface/grant_table.h>
83862ccf	15	#include <xen/interface/memory.h>
a9fd60e2	16	#include <xen/page.h>
83862ccf SS	17	#include <xen/swiotlb-xen.h>
	18
	19	#include <asm/cacheflush.h>
83862ccf SS	20	#include <asm/xen/hypercall.h>
	21	#include <asm/xen/interface.h>
	22
8746515d SS	23	unsigned long xen_get_swiotlb_free_pages(unsigned int order)
	24	{
	25	struct memblock_region *reg;
d0164adc	26	gfp_t flags = __GFP_NOWARN\|__GFP_KSWAPD_RECLAIM;
8746515d SS	27
	28	for_each_memblock(memory, reg) {
	29	if (reg->base < (phys_addr_t)0xffffffff) {
	30	flags \|= __GFP_DMA;
	31	break;
	32	}
	33	}
	34	return __get_free_pages(flags, order);
	35	}
	36
5121872a SS	37	enum dma_cache_op {
	38	DMA_UNMAP,
	39	DMA_MAP,
	40	};
da095a99	41	static bool hypercall_cflush = false;
5121872a SS	42
	43	/* functions called by SWIOTLB */
	44
	45	static void dma_cache_maint(dma_addr_t handle, unsigned long offset,
	46	size_t size, enum dma_data_direction dir, enum dma_cache_op op)
	47	{
da095a99	48	struct gnttab_cache_flush cflush;
9435cce8	49	unsigned long xen_pfn;
5121872a SS	50	size_t left = size;
5121872a SS	51
9435cce8 JG	52	xen_pfn = (handle >> XEN_PAGE_SHIFT) + offset / XEN_PAGE_SIZE;
9435cce8 JG	53	offset %= XEN_PAGE_SIZE;
5121872a SS	54
	55	do {
	56	size_t len = left;
	57
da095a99 SS	58	/* buffers in highmem or foreign pages cannot cross page
da095a99 SS	59	* boundaries */
9435cce8 JG	60	if (len + offset > XEN_PAGE_SIZE)
9435cce8 JG	61	len = XEN_PAGE_SIZE - offset;
da095a99 SS	62
da095a99 SS	63	cflush.op = 0;
9435cce8	64	cflush.a.dev_bus_addr = xen_pfn << XEN_PAGE_SHIFT;
da095a99 SS	65	cflush.offset = offset;
	66	cflush.length = len;
	67
	68	if (op == DMA_UNMAP && dir != DMA_TO_DEVICE)
	69	cflush.op = GNTTAB_CACHE_INVAL;
	70	if (op == DMA_MAP) {
	71	if (dir == DMA_FROM_DEVICE)
	72	cflush.op = GNTTAB_CACHE_INVAL;
	73	else
	74	cflush.op = GNTTAB_CACHE_CLEAN;
	75	}
	76	if (cflush.op)
	77	HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1);
5121872a SS	78
5121872a SS	79	offset = 0;
9435cce8	80	xen_pfn++;
5121872a SS	81	left -= len;
	82	} while (left);
	83	}
	84
	85	static void __xen_dma_page_dev_to_cpu(struct device *hwdev, dma_addr_t handle,
	86	size_t size, enum dma_data_direction dir)
	87	{
	88	dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, DMA_UNMAP);
	89	}
	90
	91	static void __xen_dma_page_cpu_to_dev(struct device *hwdev, dma_addr_t handle,
	92	size_t size, enum dma_data_direction dir)
	93	{
	94	dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, DMA_MAP);
	95	}
	96
	97	void __xen_dma_map_page(struct device hwdev, struct page page,
	98	dma_addr_t dev_addr, unsigned long offset, size_t size,
00085f1e	99	enum dma_data_direction dir, unsigned long attrs)
5121872a SS	100	{
	101	if (is_device_dma_coherent(hwdev))
	102	return;
00085f1e	103	if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
5121872a SS	104	return;
	105
	106	__xen_dma_page_cpu_to_dev(hwdev, dev_addr, size, dir);
	107	}
	108
	109	void __xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,
	110	size_t size, enum dma_data_direction dir,
00085f1e	111	unsigned long attrs)
5121872a SS	112
	113	{
	114	if (is_device_dma_coherent(hwdev))
	115	return;
00085f1e	116	if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
5121872a SS	117	return;
	118
	119	__xen_dma_page_dev_to_cpu(hwdev, handle, size, dir);
	120	}
	121
	122	void __xen_dma_sync_single_for_cpu(struct device *hwdev,
	123	dma_addr_t handle, size_t size, enum dma_data_direction dir)
	124	{
	125	if (is_device_dma_coherent(hwdev))
	126	return;
	127	__xen_dma_page_dev_to_cpu(hwdev, handle, size, dir);
	128	}
	129
	130	void __xen_dma_sync_single_for_device(struct device *hwdev,
	131	dma_addr_t handle, size_t size, enum dma_data_direction dir)
	132	{
	133	if (is_device_dma_coherent(hwdev))
	134	return;
	135	__xen_dma_page_cpu_to_dev(hwdev, handle, size, dir);
	136	}
	137
a4dba130	138	bool xen_arch_need_swiotlb(struct device *dev,
291be10f JG	139	phys_addr_t phys,
291be10f JG	140	dma_addr_t dev_addr)
a4dba130	141	{
9435cce8 JG	142	unsigned int xen_pfn = XEN_PFN_DOWN(phys);
	143	unsigned int bfn = XEN_PFN_DOWN(dev_addr);
	144
	145	/*
	146	* The swiotlb buffer should be used if
	147	* - Xen doesn't have the cache flush hypercall
	148	* - The Linux page refers to foreign memory
	149	* - The device doesn't support coherent DMA request
	150	*
	151	* The Linux page may be spanned acrros multiple Xen page, although
	152	* it's not possible to have a mix of local and foreign Xen page.
	153	* Furthermore, range_straddles_page_boundary is already checking
	154	* if buffer is physically contiguous in the host RAM.
	155	*
	156	* Therefore we only need to check the first Xen page to know if we
	157	* require a bounce buffer because the device doesn't support coherent
	158	* memory and we are not able to flush the cache.
	159	*/
	160	return (!hypercall_cflush && (xen_pfn != bfn) &&
	161	!is_device_dma_coherent(dev));
a4dba130 SS	162	}
a4dba130 SS	163
1b65c4e5	164	int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
83862ccf SS	165	unsigned int address_bits,
	166	dma_addr_t *dma_handle)
	167	{
	168	if (!xen_initial_domain())
	169	return -EINVAL;
	170
	171	/* we assume that dom0 is mapped 1:1 for now */
1b65c4e5	172	*dma_handle = pstart;
83862ccf SS	173	return 0;
	174	}
	175	EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
	176
1b65c4e5	177	void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
83862ccf SS	178	{
	179	return;
	180	}
	181	EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
	182
5299709d	183	const struct dma_map_ops *xen_dma_ops;
35c8ab4c	184	EXPORT_SYMBOL(xen_dma_ops);
83862ccf	185
83862ccf SS	186	int __init xen_mm_init(void)
83862ccf SS	187	{
da095a99	188	struct gnttab_cache_flush cflush;
83862ccf SS	189	if (!xen_initial_domain())
	190	return 0;
	191	xen_swiotlb_init(1, false);
	192	xen_dma_ops = &xen_swiotlb_dma_ops;
da095a99 SS	193
	194	cflush.op = 0;
	195	cflush.a.dev_bus_addr = 0;
	196	cflush.offset = 0;
	197	cflush.length = 0;
	198	if (HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1) != -ENOSYS)
	199	hypercall_cflush = true;
83862ccf SS	200	return 0;
	201	}
	202	arch_initcall(xen_mm_init);