dvma.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Virtual DMA allocation
  4 *
  5 * (C) 1999 Thomas Bogendoerfer (tsbogend@alpha.franken.de)
  6 *
  7 * 11/26/2000 -- disabled the existing code because it didn't work for
  8 * me in 2.4.  Replaced with a significantly more primitive version
  9 * similar to the sun3 code.  the old functionality was probably more
 10 * desirable, but....   -- Sam Creasey (sammy@oh.verio.com)
 11 *
 12 */
 13
 14#include <linux/kernel.h>
 15#include <linux/init.h>
 16#include <linux/bitops.h>
 17#include <linux/mm.h>
 18#include <linux/memblock.h>
 19#include <linux/vmalloc.h>
 20
 21#include <asm/sun3x.h>
 22#include <asm/dvma.h>
 23#include <asm/io.h>
 24#include <asm/page.h>
 25#include <asm/tlbflush.h>
 26
 27/* IOMMU support */
 28
 29#define IOMMU_ADDR_MASK            0x03ffe000
 30#define IOMMU_CACHE_INHIBIT        0x00000040
 31#define IOMMU_FULL_BLOCK           0x00000020
 32#define IOMMU_MODIFIED             0x00000010
 33#define IOMMU_USED                 0x00000008
 34#define IOMMU_WRITE_PROTECT        0x00000004
 35#define IOMMU_DT_MASK              0x00000003
 36#define IOMMU_DT_INVALID           0x00000000
 37#define IOMMU_DT_VALID             0x00000001
 38#define IOMMU_DT_BAD               0x00000002
 39
 40
 41static volatile unsigned long *iommu_pte = (unsigned long *)SUN3X_IOMMU;
 42
 43
 44#define dvma_entry_paddr(index)		(iommu_pte[index] & IOMMU_ADDR_MASK)
 45#define dvma_entry_vaddr(index,paddr)	((index << DVMA_PAGE_SHIFT) |  \
 46					 (paddr & (DVMA_PAGE_SIZE-1)))
 47#if 0
 48#define dvma_entry_set(index,addr)	(iommu_pte[index] =            \
 49					    (addr & IOMMU_ADDR_MASK) | \
 50				             IOMMU_DT_VALID | IOMMU_CACHE_INHIBIT)
 51#else
 52#define dvma_entry_set(index,addr)	(iommu_pte[index] =            \
 53					    (addr & IOMMU_ADDR_MASK) | \
 54				             IOMMU_DT_VALID)
 55#endif
 56#define dvma_entry_clr(index)		(iommu_pte[index] = IOMMU_DT_INVALID)
 57#define dvma_entry_hash(addr)		((addr >> DVMA_PAGE_SHIFT) ^ \
 58					 ((addr & 0x03c00000) >>     \
 59						(DVMA_PAGE_SHIFT+4)))
 60
 61#ifdef DEBUG
 62/* code to print out a dvma mapping for debugging purposes */
 63static void dvma_print (unsigned long dvma_addr)
 64{
 65
 66	unsigned long index;
 67
 68	index = dvma_addr >> DVMA_PAGE_SHIFT;
 69
 70	pr_info("idx %lx dvma_addr %08lx paddr %08lx\n", index, dvma_addr,
 71		dvma_entry_paddr(index));
 72}
 73#endif
 74
 75
 76/* create a virtual mapping for a page assigned within the IOMMU
 77   so that the cpu can reach it easily */
 78inline int dvma_map_cpu(unsigned long kaddr,
 79			       unsigned long vaddr, int len)
 80{
 81	pgd_t *pgd;
 82	p4d_t *p4d;
 83	pud_t *pud;
 84	unsigned long end;
 85	int ret = 0;
 86
 87	kaddr &= PAGE_MASK;
 88	vaddr &= PAGE_MASK;
 89
 90	end = PAGE_ALIGN(vaddr + len);
 91
 92	pr_debug("dvma: mapping kern %08lx to virt %08lx\n", kaddr, vaddr);
 93	pgd = pgd_offset_k(vaddr);
 94	p4d = p4d_offset(pgd, vaddr);
 95	pud = pud_offset(p4d, vaddr);
 96
 97	do {
 98		pmd_t *pmd;
 99		unsigned long end2;
100
101		if((pmd = pmd_alloc(&init_mm, pud, vaddr)) == NULL) {
102			ret = -ENOMEM;
103			goto out;
104		}
105
106		if((end & PGDIR_MASK) > (vaddr & PGDIR_MASK))
107			end2 = (vaddr + (PGDIR_SIZE-1)) & PGDIR_MASK;
108		else
109			end2 = end;
110
111		do {
112			pte_t *pte;
113			unsigned long end3;
114
115			if((pte = pte_alloc_kernel(pmd, vaddr)) == NULL) {
116				ret = -ENOMEM;
117				goto out;
118			}
119
120			if((end2 & PMD_MASK) > (vaddr & PMD_MASK))
121				end3 = (vaddr + (PMD_SIZE-1)) & PMD_MASK;
122			else
123				end3 = end2;
124
125			do {
126				pr_debug("mapping %08lx phys to %08lx\n",
127					 __pa(kaddr), vaddr);
128				set_pte(pte, pfn_pte(virt_to_pfn((void *)kaddr),
129						     PAGE_KERNEL));
130				pte++;
131				kaddr += PAGE_SIZE;
132				vaddr += PAGE_SIZE;
133			} while(vaddr < end3);
134
135		} while(vaddr < end2);
136
137	} while(vaddr < end);
138
139	flush_tlb_all();
140
141 out:
142	return ret;
143}
144
145
146int dvma_map_iommu(unsigned long kaddr, unsigned long baddr, int len)
147{
148	unsigned long end, index;
149
150	index = baddr >> DVMA_PAGE_SHIFT;
151	end = ((baddr+len) >> DVMA_PAGE_SHIFT);
152
153	if(len & ~DVMA_PAGE_MASK)
154		end++;
155
156	for(; index < end ; index++) {
157//		if(dvma_entry_use(index))
158//			BUG();
159//		pr_info("mapping pa %lx to ba %lx\n", __pa(kaddr),
160//			index << DVMA_PAGE_SHIFT);
161
162		dvma_entry_set(index, __pa(kaddr));
163
164		iommu_pte[index] |= IOMMU_FULL_BLOCK;
165//		dvma_entry_inc(index);
166
167		kaddr += DVMA_PAGE_SIZE;
168	}
169
170#ifdef DEBUG
171	for(index = (baddr >> DVMA_PAGE_SHIFT); index < end; index++)
172		dvma_print(index << DVMA_PAGE_SHIFT);
173#endif
174	return 0;
175
176}
177
178void dvma_unmap_iommu(unsigned long baddr, int len)
179{
180
181	int index, end;
182
183
184	index = baddr >> DVMA_PAGE_SHIFT;
185	end = (DVMA_PAGE_ALIGN(baddr+len) >> DVMA_PAGE_SHIFT);
186
187	for(; index < end ; index++) {
188		pr_debug("freeing bus mapping %08x\n",
189			 index << DVMA_PAGE_SHIFT);
190#if 0
191		if(!dvma_entry_use(index))
192			pr_info("dvma_unmap freeing unused entry %04x\n",
193				index);
194		else
195			dvma_entry_dec(index);
196#endif
197		dvma_entry_clr(index);
198	}
199
200}