io-unit.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * io-unit.c:  IO-UNIT specific routines for memory management.
  4 *
  5 * Copyright (C) 1997,1998 Jakub Jelinek    (jj@sunsite.mff.cuni.cz)
  6 */
  7 
  8#include <linux/kernel.h>
  9#include <linux/init.h>
 10#include <linux/slab.h>
 11#include <linux/spinlock.h>
 12#include <linux/mm.h>
 13#include <linux/bitops.h>
 14#include <linux/dma-map-ops.h>
 15#include <linux/of.h>
 16#include <linux/of_platform.h>
 17#include <linux/platform_device.h>
 18
 19#include <asm/io.h>
 20#include <asm/io-unit.h>
 21#include <asm/mxcc.h>
 22#include <asm/cacheflush.h>
 23#include <asm/tlbflush.h>
 24#include <asm/dma.h>
 25#include <asm/oplib.h>
 26
 27#include "mm_32.h"
 28
 29/* #define IOUNIT_DEBUG */
 30#ifdef IOUNIT_DEBUG
 31#define IOD(x) printk(x)
 32#else
 33#define IOD(x) do { } while (0)
 34#endif
 35
 36#define IOPERM        (IOUPTE_CACHE | IOUPTE_WRITE | IOUPTE_VALID)
 37#define MKIOPTE(phys) __iopte((((phys)>>4) & IOUPTE_PAGE) | IOPERM)
 38
 39static const struct dma_map_ops iounit_dma_ops;
 40
 41static void __init iounit_iommu_init(struct platform_device *op)
 42{
 43	struct iounit_struct *iounit;
 44	iopte_t __iomem *xpt;
 45	iopte_t __iomem *xptend;
 46
 47	iounit = kzalloc(sizeof(struct iounit_struct), GFP_ATOMIC);
 48	if (!iounit) {
 49		prom_printf("SUN4D: Cannot alloc iounit, halting.\n");
 50		prom_halt();
 51	}
 52
 53	iounit->limit[0] = IOUNIT_BMAP1_START;
 54	iounit->limit[1] = IOUNIT_BMAP2_START;
 55	iounit->limit[2] = IOUNIT_BMAPM_START;
 56	iounit->limit[3] = IOUNIT_BMAPM_END;
 57	iounit->rotor[1] = IOUNIT_BMAP2_START;
 58	iounit->rotor[2] = IOUNIT_BMAPM_START;
 59
 60	xpt = of_ioremap(&op->resource[2], 0, PAGE_SIZE * 16, "XPT");
 61	if (!xpt) {
 62		prom_printf("SUN4D: Cannot map External Page Table.");
 63		prom_halt();
 64	}
 65	
 66	op->dev.archdata.iommu = iounit;
 67	iounit->page_table = xpt;
 68	spin_lock_init(&iounit->lock);
 69
 70	xptend = iounit->page_table + (16 * PAGE_SIZE) / sizeof(iopte_t);
 71	for (; xpt < xptend; xpt++)
 72		sbus_writel(0, xpt);
 73
 74	op->dev.dma_ops = &iounit_dma_ops;
 75}
 76
 77static int __init iounit_init(void)
 78{
 79	extern void sun4d_init_sbi_irq(void);
 80	struct device_node *dp;
 81
 82	for_each_node_by_name(dp, "sbi") {
 83		struct platform_device *op = of_find_device_by_node(dp);
 84
 85		iounit_iommu_init(op);
 86		of_propagate_archdata(op);
 87	}
 88
 89	sun4d_init_sbi_irq();
 90
 91	return 0;
 92}
 93
 94subsys_initcall(iounit_init);
 95
 96/* One has to hold iounit->lock to call this */
 97static dma_addr_t iounit_get_area(struct iounit_struct *iounit,
 98				  phys_addr_t phys, int size)
 99{
100	int i, j, k, npages;
101	unsigned long rotor, scan, limit;
102	iopte_t iopte;
103
104	npages = (offset_in_page(phys) + size + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
105
106	/* A tiny bit of magic ingredience :) */
107	switch (npages) {
108	case 1: i = 0x0231; break;
109	case 2: i = 0x0132; break;
110	default: i = 0x0213; break;
111	}
112	
113	IOD(("%s(%pa,%d[%d])=", __func__, &phys, size, npages));
114	
115next:	j = (i & 15);
116	rotor = iounit->rotor[j - 1];
117	limit = iounit->limit[j];
118	scan = rotor;
119nexti:	scan = find_next_zero_bit(iounit->bmap, limit, scan);
120	if (scan + npages > limit) {
121		if (limit != rotor) {
122			limit = rotor;
123			scan = iounit->limit[j - 1];
124			goto nexti;
125		}
126		i >>= 4;
127		if (!(i & 15))
128			panic("iounit_get_area: Couldn't find free iopte slots for (%pa,%d)\n",
129			      &phys, size);
130		goto next;
131	}
132	for (k = 1, scan++; k < npages; k++)
133		if (test_bit(scan++, iounit->bmap))
134			goto nexti;
135	iounit->rotor[j - 1] = (scan < limit) ? scan : iounit->limit[j - 1];
136	scan -= npages;
137	iopte = MKIOPTE(phys & PAGE_MASK);
138	phys = IOUNIT_DMA_BASE + (scan << PAGE_SHIFT) + offset_in_page(phys);
139	for (k = 0; k < npages; k++, iopte = __iopte(iopte_val(iopte) + 0x100), scan++) {
140		set_bit(scan, iounit->bmap);
141		sbus_writel(iopte_val(iopte), &iounit->page_table[scan]);
142	}
143	IOD(("%pa\n", &phys));
144	return phys;
145}
146
147static dma_addr_t iounit_map_phys(struct device *dev, phys_addr_t phys,
148		size_t len, enum dma_data_direction dir, unsigned long attrs)
149{
150	struct iounit_struct *iounit = dev->archdata.iommu;
151	unsigned long flags;
152	dma_addr_t ret;
153	
154	/* XXX So what is maxphys for us and how do drivers know it? */
155	if (!len || len > 256 * 1024)
156		return DMA_MAPPING_ERROR;
157
158	spin_lock_irqsave(&iounit->lock, flags);
159	ret = iounit_get_area(iounit, phys, len);
160	spin_unlock_irqrestore(&iounit->lock, flags);
161	return ret;
162}
163
164static int iounit_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
165		enum dma_data_direction dir, unsigned long attrs)
166{
167	struct iounit_struct *iounit = dev->archdata.iommu;
168	struct scatterlist *sg;
169	unsigned long flags;
170	int i;
171
172	/* FIXME: Cache some resolved pages - often several sg entries are to the same page */
173	spin_lock_irqsave(&iounit->lock, flags);
174	for_each_sg(sgl, sg, nents, i) {
175		sg->dma_address =
176			iounit_get_area(iounit, sg_phys(sg), sg->length);
177		sg->dma_length = sg->length;
178	}
179	spin_unlock_irqrestore(&iounit->lock, flags);
180	return nents;
181}
182
183static void iounit_unmap_phys(struct device *dev, dma_addr_t vaddr, size_t len,
184		enum dma_data_direction dir, unsigned long attrs)
185{
186	struct iounit_struct *iounit = dev->archdata.iommu;
187	unsigned long flags;
188	
189	spin_lock_irqsave(&iounit->lock, flags);
190	len = ((vaddr & ~PAGE_MASK) + len + (PAGE_SIZE-1)) >> PAGE_SHIFT;
191	vaddr = (vaddr - IOUNIT_DMA_BASE) >> PAGE_SHIFT;
192	IOD(("iounit_release %08lx-%08lx\n", (long)vaddr, (long)len+vaddr));
193	for (len += vaddr; vaddr < len; vaddr++)
194		clear_bit(vaddr, iounit->bmap);
195	spin_unlock_irqrestore(&iounit->lock, flags);
196}
197
198static void iounit_unmap_sg(struct device *dev, struct scatterlist *sgl,
199		int nents, enum dma_data_direction dir, unsigned long attrs)
200{
201	struct iounit_struct *iounit = dev->archdata.iommu;
202	unsigned long flags, vaddr, len;
203	struct scatterlist *sg;
204	int i;
205
206	spin_lock_irqsave(&iounit->lock, flags);
207	for_each_sg(sgl, sg, nents, i) {
208		len = ((sg->dma_address & ~PAGE_MASK) + sg->length + (PAGE_SIZE-1)) >> PAGE_SHIFT;
209		vaddr = (sg->dma_address - IOUNIT_DMA_BASE) >> PAGE_SHIFT;
210		IOD(("iounit_release %08lx-%08lx\n", (long)vaddr, (long)len+vaddr));
211		for (len += vaddr; vaddr < len; vaddr++)
212			clear_bit(vaddr, iounit->bmap);
213	}
214	spin_unlock_irqrestore(&iounit->lock, flags);
215}
216
217#ifdef CONFIG_SBUS
218static void *iounit_alloc(struct device *dev, size_t len,
219		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
220{
221	struct iounit_struct *iounit = dev->archdata.iommu;
222	unsigned long va, addr, page, end, ret;
223	pgprot_t dvma_prot;
224	iopte_t __iomem *iopte;
225
226	/* XXX So what is maxphys for us and how do drivers know it? */
227	if (!len || len > 256 * 1024)
228		return NULL;
229
230	len = PAGE_ALIGN(len);
231	va = __get_free_pages(gfp | __GFP_ZERO, get_order(len));
232	if (!va)
233		return NULL;
234
235	addr = ret = sparc_dma_alloc_resource(dev, len);
236	if (!addr)
237		goto out_free_pages;
238	*dma_handle = addr;
239
240	dvma_prot = __pgprot(SRMMU_CACHE | SRMMU_ET_PTE | SRMMU_PRIV);
241	end = PAGE_ALIGN((addr + len));
242	while(addr < end) {
243		page = va;
244		{
245			pmd_t *pmdp;
246			pte_t *ptep;
247			long i;
248
249			pmdp = pmd_off_k(addr);
250			ptep = pte_offset_kernel(pmdp, addr);
251
252			set_pte(ptep, mk_pte(virt_to_page(page), dvma_prot));
253
254			i = ((addr - IOUNIT_DMA_BASE) >> PAGE_SHIFT);
255
256			iopte = iounit->page_table + i;
257			sbus_writel(iopte_val(MKIOPTE(__pa(page))), iopte);
258		}
259		addr += PAGE_SIZE;
260		va += PAGE_SIZE;
261	}
262	flush_cache_all();
263	flush_tlb_all();
264
265	return (void *)ret;
266
267out_free_pages:
268	free_pages(va, get_order(len));
269	return NULL;
270}
271
272static void iounit_free(struct device *dev, size_t size, void *cpu_addr,
273		dma_addr_t dma_addr, unsigned long attrs)
274{
275	/* XXX Somebody please fill this in */
276}
277#endif
278
279static const struct dma_map_ops iounit_dma_ops = {
280#ifdef CONFIG_SBUS
281	.alloc			= iounit_alloc,
282	.free			= iounit_free,
283#endif
284	.map_phys		= iounit_map_phys,
285	.unmap_phys		= iounit_unmap_phys,
286	.map_sg			= iounit_map_sg,
287	.unmap_sg		= iounit_unmap_sg,
288};