1/* dma-alloc.c: consistent DMA memory allocation
2 *
3 * Derived from arch/ppc/mm/cachemap.c
4 *
5 *  PowerPC version derived from arch/arm/mm/consistent.c
6 *    Copyright (C) 2001 Dan Malek (dmalek@jlc.net)
7 *
8 *  linux/arch/arm/mm/consistent.c
9 *
10 *  Copyright (C) 2000 Russell King
11 *
12 * Consistent memory allocators.  Used for DMA devices that want to
13 * share uncached memory with the processor core.  The function return
14 * is the virtual address and 'dma_handle' is the physical address.
15 * Mostly stolen from the ARM port, with some changes for PowerPC.
16 *						-- Dan
17 * Modified for 36-bit support.  -Matt
18 *
19 * This program is free software; you can redistribute it and/or modify
20 * it under the terms of the GNU General Public License version 2 as
21 * published by the Free Software Foundation.
22 */
23
24#include <linux/module.h>
25#include <linux/signal.h>
26#include <linux/sched.h>
27#include <linux/kernel.h>
28#include <linux/errno.h>
29#include <linux/string.h>
30#include <linux/types.h>
31#include <linux/ptrace.h>
32#include <linux/mman.h>
33#include <linux/mm.h>
34#include <linux/swap.h>
35#include <linux/stddef.h>
36#include <linux/vmalloc.h>
37#include <linux/init.h>
38#include <linux/pci.h>
39
40#include <asm/pgalloc.h>
41#include <asm/io.h>
42#include <asm/hardirq.h>
43#include <asm/mmu_context.h>
44#include <asm/pgtable.h>
45#include <asm/mmu.h>
46#include <asm/uaccess.h>
47#include <asm/smp.h>
48
49static int map_page(unsigned long va, unsigned long pa, pgprot_t prot)
50{
51	pgd_t *pge;
52	pud_t *pue;
53	pmd_t *pme;
54	pte_t *pte;
55	int err = -ENOMEM;
56
57	/* Use upper 10 bits of VA to index the first level map */
58	pge = pgd_offset_k(va);
59	pue = pud_offset(pge, va);
60	pme = pmd_offset(pue, va);
61
62	/* Use middle 10 bits of VA to index the second-level map */
63	pte = pte_alloc_kernel(pme, va);
64	if (pte != 0) {
65		err = 0;
66		set_pte(pte, mk_pte_phys(pa & PAGE_MASK, prot));
67	}
68
69	return err;
70}
71
72/*
73 * This function will allocate the requested contiguous pages and
74 * map them into the kernel's vmalloc() space.  This is done so we
75 * get unique mapping for these pages, outside of the kernel's 1:1
76 * virtual:physical mapping.  This is necessary so we can cover large
77 * portions of the kernel with single large page TLB entries, and
78 * still get unique uncached pages for consistent DMA.
79 */
80void *consistent_alloc(gfp_t gfp, size_t size, dma_addr_t *dma_handle)
81{
82	struct vm_struct *area;
83	unsigned long page, va, pa;
84	void *ret;
85	int order, err, i;
86
87	if (in_interrupt())
88		BUG();
89
90	/* only allocate page size areas */
91	size = PAGE_ALIGN(size);
92	order = get_order(size);
93
94	page = __get_free_pages(gfp, order);
95	if (!page) {
96		BUG();
97		return NULL;
98	}
99
100	/* allocate some common virtual space to map the new pages */
101	area = get_vm_area(size, VM_ALLOC);
102	if (area == 0) {
103		free_pages(page, order);
104		return NULL;
105	}
106	va = VMALLOC_VMADDR(area->addr);
107	ret = (void *) va;
108
109	/* this gives us the real physical address of the first page */
110	*dma_handle = pa = virt_to_bus((void *) page);
111
112	/* set refcount=1 on all pages in an order>0 allocation so that vfree() will actually free
113	 * all pages that were allocated.
114	 */
115	if (order > 0) {
116		struct page *rpage = virt_to_page(page);
117		split_page(rpage, order);
118	}
119
120	err = 0;
121	for (i = 0; i < size && err == 0; i += PAGE_SIZE)
122		err = map_page(va + i, pa + i, PAGE_KERNEL_NOCACHE);
123
124	if (err) {
125		vfree((void *) va);
126		return NULL;
127	}
128
129	/* we need to ensure that there are no cachelines in use, or worse dirty in this area
130	 * - can't do until after virtual address mappings are created
131	 */
132	frv_cache_invalidate(va, va + size);
133
134	return ret;
135}
136
137/*
138 * free page(s) as defined by the above mapping.
139 */
140void consistent_free(void *vaddr)
141{
142	if (in_interrupt())
143		BUG();
144	vfree(vaddr);
145}
146
147/*
148 * make an area consistent.
149 */
150void consistent_sync(void *vaddr, size_t size, int direction)
151{
152	unsigned long start = (unsigned long) vaddr;
153	unsigned long end   = start + size;
154
155	switch (direction) {
156	case PCI_DMA_NONE:
157		BUG();
158	case PCI_DMA_FROMDEVICE:	/* invalidate only */
159		frv_cache_invalidate(start, end);
160		break;
161	case PCI_DMA_TODEVICE:		/* writeback only */
162		frv_dcache_writeback(start, end);
163		break;
164	case PCI_DMA_BIDIRECTIONAL:	/* writeback and invalidate */
165		frv_dcache_writeback(start, end);
166		break;
167	}
168}
169
170/*
171 * consistent_sync_page make a page are consistent. identical
172 * to consistent_sync, but takes a struct page instead of a virtual address
173 */
174
175void consistent_sync_page(struct page *page, unsigned long offset,
176			  size_t size, int direction)
177{
178	void *start;
179
180	start = page_address(page) + offset;
181	consistent_sync(start, size, direction);
182}
183