1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *  Port on Texas Instruments TMS320C6x architecture
4 *
5 *  Copyright (C) 2004, 2009, 2010, 2011 Texas Instruments Incorporated
6 *  Author: Aurelien Jacquiot <aurelien.jacquiot@ti.com>
7 *
8 *  DMA uncached mapping support.
9 *
10 *  Using code pulled from ARM
11 *  Copyright (C) 2000-2004 Russell King
12 */
13#include <linux/slab.h>
14#include <linux/bitmap.h>
15#include <linux/bitops.h>
16#include <linux/module.h>
17#include <linux/interrupt.h>
18#include <linux/dma-map-ops.h>
19#include <linux/memblock.h>
20
21#include <asm/cacheflush.h>
22#include <asm/page.h>
23#include <asm/setup.h>
24
25/*
26 * DMA coherent memory management, can be redefined using the memdma=
27 * kernel command line
28 */
29
30/* none by default */
31static phys_addr_t dma_base;
32static u32 dma_size;
33static u32 dma_pages;
34
35static unsigned long *dma_bitmap;
36
37/* bitmap lock */
38static DEFINE_SPINLOCK(dma_lock);
39
40/*
41 * Return a DMA coherent and contiguous memory chunk from the DMA memory
42 */
43static inline u32 __alloc_dma_pages(int order)
44{
45	unsigned long flags;
46	u32 pos;
47
48	spin_lock_irqsave(&dma_lock, flags);
49	pos = bitmap_find_free_region(dma_bitmap, dma_pages, order);
50	spin_unlock_irqrestore(&dma_lock, flags);
51
52	return dma_base + (pos << PAGE_SHIFT);
53}
54
55static void __free_dma_pages(u32 addr, int order)
56{
57	unsigned long flags;
58	u32 pos = (addr - dma_base) >> PAGE_SHIFT;
59
60	if (addr < dma_base || (pos + (1 << order)) >= dma_pages) {
61		printk(KERN_ERR "%s: freeing outside range.\n", __func__);
62		BUG();
63	}
64
65	spin_lock_irqsave(&dma_lock, flags);
66	bitmap_release_region(dma_bitmap, pos, order);
67	spin_unlock_irqrestore(&dma_lock, flags);
68}
69
70/*
71 * Allocate DMA coherent memory space and return both the kernel
72 * virtual and DMA address for that space.
73 */
74void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
75		gfp_t gfp, unsigned long attrs)
76{
77	void *ret;
78	u32 paddr;
79	int order;
80
81	if (!dma_size || !size)
82		return NULL;
83
84	order = get_count_order(((size - 1) >> PAGE_SHIFT) + 1);
85
86	paddr = __alloc_dma_pages(order);
87
88	if (handle)
89		*handle = paddr;
90
91	if (!paddr)
92		return NULL;
93
94	ret = phys_to_virt(paddr);
95	memset(ret, 0, 1 << order);
96	return ret;
97}
98
99/*
100 * Free DMA coherent memory as defined by the above mapping.
101 */
102void arch_dma_free(struct device *dev, size_t size, void *vaddr,
103		dma_addr_t dma_handle, unsigned long attrs)
104{
105	int order;
106
107	if (!dma_size || !size)
108		return;
109
110	order = get_count_order(((size - 1) >> PAGE_SHIFT) + 1);
111
112	__free_dma_pages(virt_to_phys(vaddr), order);
113}
114
115/*
116 * Initialise the coherent DMA memory allocator using the given uncached region.
117 */
118void __init coherent_mem_init(phys_addr_t start, u32 size)
119{
120	if (!size)
121		return;
122
123	printk(KERN_INFO
124	       "Coherent memory (DMA) region start=0x%x size=0x%x\n",
125	       start, size);
126
127	dma_base = start;
128	dma_size = size;
129
130	/* allocate bitmap */
131	dma_pages = dma_size >> PAGE_SHIFT;
132	if (dma_size & (PAGE_SIZE - 1))
133		++dma_pages;
134
135	dma_bitmap = memblock_alloc(BITS_TO_LONGS(dma_pages) * sizeof(long),
136				    sizeof(long));
137	if (!dma_bitmap)
138		panic("%s: Failed to allocate %zu bytes align=0x%zx\n",
139		      __func__, BITS_TO_LONGS(dma_pages) * sizeof(long),
140		      sizeof(long));
141}
142
143static void c6x_dma_sync(phys_addr_t paddr, size_t size,
144		enum dma_data_direction dir)
145{
146	BUG_ON(!valid_dma_direction(dir));
147
148	switch (dir) {
149	case DMA_FROM_DEVICE:
150		L2_cache_block_invalidate(paddr, paddr + size);
151		break;
152	case DMA_TO_DEVICE:
153		L2_cache_block_writeback(paddr, paddr + size);
154		break;
155	case DMA_BIDIRECTIONAL:
156		L2_cache_block_writeback_invalidate(paddr, paddr + size);
157		break;
158	default:
159		break;
160	}
161}
162
163void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
164		enum dma_data_direction dir)
165{
166	return c6x_dma_sync(paddr, size, dir);
167}
168
169void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
170		enum dma_data_direction dir)
171{
172	return c6x_dma_sync(paddr, size, dir);
173}
174