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 unsigned long iounit_get_area(struct iounit_struct *iounit, unsigned long vaddr, int size)
98{
99	int i, j, k, npages;
100	unsigned long rotor, scan, limit;
101	iopte_t iopte;
102
103        npages = ((vaddr & ~PAGE_MASK) + size + (PAGE_SIZE-1)) >> PAGE_SHIFT;
104
105	/* A tiny bit of magic ingredience :) */
106	switch (npages) {
107	case 1: i = 0x0231; break;
108	case 2: i = 0x0132; break;
109	default: i = 0x0213; break;
110	}
111
112	IOD(("iounit_get_area(%08lx,%d[%d])=", vaddr, size, npages));
113
114next:	j = (i & 15);
115	rotor = iounit->rotor[j - 1];
116	limit = iounit->limit[j];
117	scan = rotor;
118nexti:	scan = find_next_zero_bit(iounit->bmap, limit, scan);
119	if (scan + npages > limit) {
120		if (limit != rotor) {
121			limit = rotor;
122			scan = iounit->limit[j - 1];
123			goto nexti;
124		}
125		i >>= 4;
126		if (!(i & 15))
127			panic("iounit_get_area: Couldn't find free iopte slots for (%08lx,%d)\n", vaddr, size);
128		goto next;
129	}
130	for (k = 1, scan++; k < npages; k++)
131		if (test_bit(scan++, iounit->bmap))
132			goto nexti;
133	iounit->rotor[j - 1] = (scan < limit) ? scan : iounit->limit[j - 1];
134	scan -= npages;
135	iopte = MKIOPTE(__pa(vaddr & PAGE_MASK));
136	vaddr = IOUNIT_DMA_BASE + (scan << PAGE_SHIFT) + (vaddr & ~PAGE_MASK);
137	for (k = 0; k < npages; k++, iopte = __iopte(iopte_val(iopte) + 0x100), scan++) {
138		set_bit(scan, iounit->bmap);
139		sbus_writel(iopte_val(iopte), &iounit->page_table[scan]);
140	}
141	IOD(("%08lx\n", vaddr));
142	return vaddr;
143}
144
145static dma_addr_t iounit_map_page(struct device *dev, struct page *page,
146		unsigned long offset, size_t len, enum dma_data_direction dir,
147		unsigned long attrs)
148{
149	void *vaddr = page_address(page) + offset;
150	struct iounit_struct *iounit = dev->archdata.iommu;
151	unsigned long ret, flags;
152
153	/* XXX So what is maxphys for us and how do drivers know it? */
154	if (!len || len > 256 * 1024)
155		return DMA_MAPPING_ERROR;
156
157	spin_lock_irqsave(&iounit->lock, flags);
158	ret = iounit_get_area(iounit, (unsigned long)vaddr, len);
159	spin_unlock_irqrestore(&iounit->lock, flags);
160	return ret;
161}
162
163static int iounit_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
164		enum dma_data_direction dir, unsigned long attrs)
165{
166	struct iounit_struct *iounit = dev->archdata.iommu;
167	struct scatterlist *sg;
168	unsigned long flags;
169	int i;
170
171	/* FIXME: Cache some resolved pages - often several sg entries are to the same page */
172	spin_lock_irqsave(&iounit->lock, flags);
173	for_each_sg(sgl, sg, nents, i) {
174		sg->dma_address = iounit_get_area(iounit, (unsigned long) sg_virt(sg), sg->length);
175		sg->dma_length = sg->length;
176	}
177	spin_unlock_irqrestore(&iounit->lock, flags);
178	return nents;
179}
180
181static void iounit_unmap_page(struct device *dev, dma_addr_t vaddr, size_t len,
182		enum dma_data_direction dir, unsigned long attrs)
183{
184	struct iounit_struct *iounit = dev->archdata.iommu;
185	unsigned long flags;
186
187	spin_lock_irqsave(&iounit->lock, flags);
188	len = ((vaddr & ~PAGE_MASK) + len + (PAGE_SIZE-1)) >> PAGE_SHIFT;
189	vaddr = (vaddr - IOUNIT_DMA_BASE) >> PAGE_SHIFT;
190	IOD(("iounit_release %08lx-%08lx\n", (long)vaddr, (long)len+vaddr));
191	for (len += vaddr; vaddr < len; vaddr++)
192		clear_bit(vaddr, iounit->bmap);
193	spin_unlock_irqrestore(&iounit->lock, flags);
194}
195
196static void iounit_unmap_sg(struct device *dev, struct scatterlist *sgl,
197		int nents, enum dma_data_direction dir, unsigned long attrs)
198{
199	struct iounit_struct *iounit = dev->archdata.iommu;
200	unsigned long flags, vaddr, len;
201	struct scatterlist *sg;
202	int i;
203
204	spin_lock_irqsave(&iounit->lock, flags);
205	for_each_sg(sgl, sg, nents, i) {
206		len = ((sg->dma_address & ~PAGE_MASK) + sg->length + (PAGE_SIZE-1)) >> PAGE_SHIFT;
207		vaddr = (sg->dma_address - IOUNIT_DMA_BASE) >> PAGE_SHIFT;
208		IOD(("iounit_release %08lx-%08lx\n", (long)vaddr, (long)len+vaddr));
209		for (len += vaddr; vaddr < len; vaddr++)
210			clear_bit(vaddr, iounit->bmap);
211	}
212	spin_unlock_irqrestore(&iounit->lock, flags);
213}
214
215#ifdef CONFIG_SBUS
216static void *iounit_alloc(struct device *dev, size_t len,
217		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
218{
219	struct iounit_struct *iounit = dev->archdata.iommu;
220	unsigned long va, addr, page, end, ret;
221	pgprot_t dvma_prot;
222	iopte_t __iomem *iopte;
223
224	/* XXX So what is maxphys for us and how do drivers know it? */
225	if (!len || len > 256 * 1024)
226		return NULL;
227
228	len = PAGE_ALIGN(len);
229	va = __get_free_pages(gfp | __GFP_ZERO, get_order(len));
230	if (!va)
231		return NULL;
232
233	addr = ret = sparc_dma_alloc_resource(dev, len);
234	if (!addr)
235		goto out_free_pages;
236	*dma_handle = addr;
237
238	dvma_prot = __pgprot(SRMMU_CACHE | SRMMU_ET_PTE | SRMMU_PRIV);
239	end = PAGE_ALIGN((addr + len));
240	while(addr < end) {
241		page = va;
242		{
243			pmd_t *pmdp;
244			pte_t *ptep;
245			long i;
246
247			pmdp = pmd_off_k(addr);
248			ptep = pte_offset_kernel(pmdp, addr);
249
250			set_pte(ptep, mk_pte(virt_to_page(page), dvma_prot));
251
252			i = ((addr - IOUNIT_DMA_BASE) >> PAGE_SHIFT);
253
254			iopte = iounit->page_table + i;
255			sbus_writel(iopte_val(MKIOPTE(__pa(page))), iopte);
256		}
257		addr += PAGE_SIZE;
258		va += PAGE_SIZE;
259	}
260	flush_cache_all();
261	flush_tlb_all();
262
263	return (void *)ret;
264
265out_free_pages:
266	free_pages(va, get_order(len));
267	return NULL;
268}
269
270static void iounit_free(struct device *dev, size_t size, void *cpu_addr,
271		dma_addr_t dma_addr, unsigned long attrs)
272{
273	/* XXX Somebody please fill this in */
274}
275#endif
276
277static const struct dma_map_ops iounit_dma_ops = {
278#ifdef CONFIG_SBUS
279	.alloc			= iounit_alloc,
280	.free			= iounit_free,
281#endif
282	.map_page		= iounit_map_page,
283	.unmap_page		= iounit_unmap_page,
284	.map_sg			= iounit_map_sg,
285	.unmap_sg		= iounit_unmap_sg,
286};
287