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#include <linux/hardirq.h>
 40#include <linux/gfp.h>
 41
 42#include <asm/pgalloc.h>
 43#include <asm/io.h>
 44#include <asm/mmu_context.h>
 45#include <asm/pgtable.h>
 46#include <asm/mmu.h>
 47#include <asm/uaccess.h>
 48#include <asm/smp.h>
 49
 50static int map_page(unsigned long va, unsigned long pa, pgprot_t prot)
 51{
 52	pgd_t *pge;
 53	pud_t *pue;
 54	pmd_t *pme;
 55	pte_t *pte;
 56	int err = -ENOMEM;
 57
 58	/* Use upper 10 bits of VA to index the first level map */
 59	pge = pgd_offset_k(va);
 60	pue = pud_offset(pge, va);
 61	pme = pmd_offset(pue, va);
 62
 63	/* Use middle 10 bits of VA to index the second-level map */
 64	pte = pte_alloc_kernel(pme, va);
 65	if (pte != 0) {
 66		err = 0;
 67		set_pte(pte, mk_pte_phys(pa & PAGE_MASK, prot));
 68	}
 69
 70	return err;
 71}
 72
 73/*
 74 * This function will allocate the requested contiguous pages and
 75 * map them into the kernel's vmalloc() space.  This is done so we
 76 * get unique mapping for these pages, outside of the kernel's 1:1
 77 * virtual:physical mapping.  This is necessary so we can cover large
 78 * portions of the kernel with single large page TLB entries, and
 79 * still get unique uncached pages for consistent DMA.
 80 */
 81void *consistent_alloc(gfp_t gfp, size_t size, dma_addr_t *dma_handle)
 82{
 83	struct vm_struct *area;
 84	unsigned long page, va, pa;
 85	void *ret;
 86	int order, err, i;
 87
 88	if (in_interrupt())
 89		BUG();
 90
 91	/* only allocate page size areas */
 92	size = PAGE_ALIGN(size);
 93	order = get_order(size);
 94
 95	page = __get_free_pages(gfp, order);
 96	if (!page) {
 97		BUG();
 98		return NULL;
 99	}
100
101	/* allocate some common virtual space to map the new pages */
102	area = get_vm_area(size, VM_ALLOC);
103	if (area == 0) {
104		free_pages(page, order);
105		return NULL;
106	}
107	va = VMALLOC_VMADDR(area->addr);
108	ret = (void *) va;
109
110	/* this gives us the real physical address of the first page */
111	*dma_handle = pa = virt_to_bus((void *) page);
112
113	/* set refcount=1 on all pages in an order>0 allocation so that vfree() will actually free
114	 * all pages that were allocated.
115	 */
116	if (order > 0) {
117		struct page *rpage = virt_to_page(page);
118		split_page(rpage, order);
119	}
120
121	err = 0;
122	for (i = 0; i < size && err == 0; i += PAGE_SIZE)
123		err = map_page(va + i, pa + i, PAGE_KERNEL_NOCACHE);
124
125	if (err) {
126		vfree((void *) va);
127		return NULL;
128	}
129
130	/* we need to ensure that there are no cachelines in use, or worse dirty in this area
131	 * - can't do until after virtual address mappings are created
132	 */
133	frv_cache_invalidate(va, va + size);
134
135	return ret;
136}
137
138/*
139 * free page(s) as defined by the above mapping.
140 */
141void consistent_free(void *vaddr)
142{
143	if (in_interrupt())
144		BUG();
145	vfree(vaddr);
146}
147
148/*
149 * make an area consistent.
150 */
151void consistent_sync(void *vaddr, size_t size, int direction)
152{
153	unsigned long start = (unsigned long) vaddr;
154	unsigned long end   = start + size;
155
156	switch (direction) {
157	case PCI_DMA_NONE:
158		BUG();
159	case PCI_DMA_FROMDEVICE:	/* invalidate only */
160		frv_cache_invalidate(start, end);
161		break;
162	case PCI_DMA_TODEVICE:		/* writeback only */
163		frv_dcache_writeback(start, end);
164		break;
165	case PCI_DMA_BIDIRECTIONAL:	/* writeback and invalidate */
166		frv_dcache_writeback(start, end);
167		break;
168	}
169}
170
171/*
172 * consistent_sync_page make a page are consistent. identical
173 * to consistent_sync, but takes a struct page instead of a virtual address
174 */
175
176void consistent_sync_page(struct page *page, unsigned long offset,
177			  size_t size, int direction)
178{
179	void *start;
180
181	start = page_address(page) + offset;
182	consistent_sync(start, size, direction);
183}