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1/*
2 * linux/arch/cris/arch-v10/mm/init.c
3 *
4 */
5#include <linux/mmzone.h>
6#include <linux/init.h>
7#include <linux/bootmem.h>
8#include <linux/mm.h>
9#include <asm/pgtable.h>
10#include <asm/page.h>
11#include <asm/types.h>
12#include <asm/mmu.h>
13#include <asm/io.h>
14#include <asm/mmu_context.h>
15#include <arch/svinto.h>
16
17extern void tlb_init(void);
18
19/*
20 * The kernel is already mapped with a kernel segment at kseg_c so
21 * we don't need to map it with a page table. However head.S also
22 * temporarily mapped it at kseg_4 so we should set up the ksegs again,
23 * clear the TLB and do some other paging setup stuff.
24 */
25
26void __init
27paging_init(void)
28{
29 int i;
30 unsigned long zones_size[MAX_NR_ZONES];
31
32 printk("Setting up paging and the MMU.\n");
33
34 /* clear out the init_mm.pgd that will contain the kernel's mappings */
35
36 for(i = 0; i < PTRS_PER_PGD; i++)
37 swapper_pg_dir[i] = __pgd(0);
38
39 /* make sure the current pgd table points to something sane
40 * (even if it is most probably not used until the next
41 * switch_mm)
42 */
43
44 per_cpu(current_pgd, smp_processor_id()) = init_mm.pgd;
45
46 /* initialise the TLB (tlb.c) */
47
48 tlb_init();
49
50 /* see README.mm for details on the KSEG setup */
51
52#ifdef CONFIG_CRIS_LOW_MAP
53 /* Etrax-100 LX version 1 has a bug so that we cannot map anything
54 * across the 0x80000000 boundary, so we need to shrink the user-virtual
55 * area to 0x50000000 instead of 0xb0000000 and map things slightly
56 * different. The unused areas are marked as paged so that we can catch
57 * freak kernel accesses there.
58 *
59 * The ARTPEC chip is mapped at 0xa so we pass that segment straight
60 * through. We cannot vremap it because the vmalloc area is below 0x8
61 * and Juliette needs an uncached area above 0x8.
62 *
63 * Same thing with 0xc and 0x9, which is memory-mapped I/O on some boards.
64 * We map them straight over in LOW_MAP, but use vremap in LX version 2.
65 */
66
67#define CACHED_BOOTROM (KSEG_F | 0x08000000UL)
68
69 *R_MMU_KSEG = ( IO_STATE(R_MMU_KSEG, seg_f, seg ) | /* bootrom */
70 IO_STATE(R_MMU_KSEG, seg_e, page ) |
71 IO_STATE(R_MMU_KSEG, seg_d, page ) |
72 IO_STATE(R_MMU_KSEG, seg_c, page ) |
73 IO_STATE(R_MMU_KSEG, seg_b, seg ) | /* kernel reg area */
74#ifdef CONFIG_JULIETTE
75 IO_STATE(R_MMU_KSEG, seg_a, seg ) | /* ARTPEC etc. */
76#else
77 IO_STATE(R_MMU_KSEG, seg_a, page ) |
78#endif
79 IO_STATE(R_MMU_KSEG, seg_9, seg ) | /* LED's on some boards */
80 IO_STATE(R_MMU_KSEG, seg_8, seg ) | /* CSE0/1, flash and I/O */
81 IO_STATE(R_MMU_KSEG, seg_7, page ) | /* kernel vmalloc area */
82 IO_STATE(R_MMU_KSEG, seg_6, seg ) | /* kernel DRAM area */
83 IO_STATE(R_MMU_KSEG, seg_5, seg ) | /* cached flash */
84 IO_STATE(R_MMU_KSEG, seg_4, page ) | /* user area */
85 IO_STATE(R_MMU_KSEG, seg_3, page ) | /* user area */
86 IO_STATE(R_MMU_KSEG, seg_2, page ) | /* user area */
87 IO_STATE(R_MMU_KSEG, seg_1, page ) | /* user area */
88 IO_STATE(R_MMU_KSEG, seg_0, page ) ); /* user area */
89
90 *R_MMU_KBASE_HI = ( IO_FIELD(R_MMU_KBASE_HI, base_f, 0x3 ) |
91 IO_FIELD(R_MMU_KBASE_HI, base_e, 0x0 ) |
92 IO_FIELD(R_MMU_KBASE_HI, base_d, 0x0 ) |
93 IO_FIELD(R_MMU_KBASE_HI, base_c, 0x0 ) |
94 IO_FIELD(R_MMU_KBASE_HI, base_b, 0xb ) |
95#ifdef CONFIG_JULIETTE
96 IO_FIELD(R_MMU_KBASE_HI, base_a, 0xa ) |
97#else
98 IO_FIELD(R_MMU_KBASE_HI, base_a, 0x0 ) |
99#endif
100 IO_FIELD(R_MMU_KBASE_HI, base_9, 0x9 ) |
101 IO_FIELD(R_MMU_KBASE_HI, base_8, 0x8 ) );
102
103 *R_MMU_KBASE_LO = ( IO_FIELD(R_MMU_KBASE_LO, base_7, 0x0 ) |
104 IO_FIELD(R_MMU_KBASE_LO, base_6, 0x4 ) |
105 IO_FIELD(R_MMU_KBASE_LO, base_5, 0x0 ) |
106 IO_FIELD(R_MMU_KBASE_LO, base_4, 0x0 ) |
107 IO_FIELD(R_MMU_KBASE_LO, base_3, 0x0 ) |
108 IO_FIELD(R_MMU_KBASE_LO, base_2, 0x0 ) |
109 IO_FIELD(R_MMU_KBASE_LO, base_1, 0x0 ) |
110 IO_FIELD(R_MMU_KBASE_LO, base_0, 0x0 ) );
111#else
112 /* This code is for the corrected Etrax-100 LX version 2... */
113
114#define CACHED_BOOTROM (KSEG_A | 0x08000000UL)
115
116 *R_MMU_KSEG = ( IO_STATE(R_MMU_KSEG, seg_f, seg ) | /* cached flash */
117 IO_STATE(R_MMU_KSEG, seg_e, seg ) | /* uncached flash */
118 IO_STATE(R_MMU_KSEG, seg_d, page ) | /* vmalloc area */
119 IO_STATE(R_MMU_KSEG, seg_c, seg ) | /* kernel area */
120 IO_STATE(R_MMU_KSEG, seg_b, seg ) | /* kernel reg area */
121 IO_STATE(R_MMU_KSEG, seg_a, seg ) | /* bootrom */
122 IO_STATE(R_MMU_KSEG, seg_9, page ) | /* user area */
123 IO_STATE(R_MMU_KSEG, seg_8, page ) |
124 IO_STATE(R_MMU_KSEG, seg_7, page ) |
125 IO_STATE(R_MMU_KSEG, seg_6, page ) |
126 IO_STATE(R_MMU_KSEG, seg_5, page ) |
127 IO_STATE(R_MMU_KSEG, seg_4, page ) |
128 IO_STATE(R_MMU_KSEG, seg_3, page ) |
129 IO_STATE(R_MMU_KSEG, seg_2, page ) |
130 IO_STATE(R_MMU_KSEG, seg_1, page ) |
131 IO_STATE(R_MMU_KSEG, seg_0, page ) );
132
133 *R_MMU_KBASE_HI = ( IO_FIELD(R_MMU_KBASE_HI, base_f, 0x0 ) |
134 IO_FIELD(R_MMU_KBASE_HI, base_e, 0x8 ) |
135 IO_FIELD(R_MMU_KBASE_HI, base_d, 0x0 ) |
136 IO_FIELD(R_MMU_KBASE_HI, base_c, 0x4 ) |
137 IO_FIELD(R_MMU_KBASE_HI, base_b, 0xb ) |
138 IO_FIELD(R_MMU_KBASE_HI, base_a, 0x3 ) |
139 IO_FIELD(R_MMU_KBASE_HI, base_9, 0x0 ) |
140 IO_FIELD(R_MMU_KBASE_HI, base_8, 0x0 ) );
141
142 *R_MMU_KBASE_LO = ( IO_FIELD(R_MMU_KBASE_LO, base_7, 0x0 ) |
143 IO_FIELD(R_MMU_KBASE_LO, base_6, 0x0 ) |
144 IO_FIELD(R_MMU_KBASE_LO, base_5, 0x0 ) |
145 IO_FIELD(R_MMU_KBASE_LO, base_4, 0x0 ) |
146 IO_FIELD(R_MMU_KBASE_LO, base_3, 0x0 ) |
147 IO_FIELD(R_MMU_KBASE_LO, base_2, 0x0 ) |
148 IO_FIELD(R_MMU_KBASE_LO, base_1, 0x0 ) |
149 IO_FIELD(R_MMU_KBASE_LO, base_0, 0x0 ) );
150#endif
151
152 *R_MMU_CONTEXT = ( IO_FIELD(R_MMU_CONTEXT, page_id, 0 ) );
153
154 /* The MMU has been enabled ever since head.S but just to make
155 * it totally obvious we do it here as well.
156 */
157
158 *R_MMU_CTRL = ( IO_STATE(R_MMU_CTRL, inv_excp, enable ) |
159 IO_STATE(R_MMU_CTRL, acc_excp, enable ) |
160 IO_STATE(R_MMU_CTRL, we_excp, enable ) );
161
162 *R_MMU_ENABLE = IO_STATE(R_MMU_ENABLE, mmu_enable, enable);
163
164 /*
165 * initialize the bad page table and bad page to point
166 * to a couple of allocated pages
167 */
168
169 empty_zero_page = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
170 memset((void *)empty_zero_page, 0, PAGE_SIZE);
171
172 /* All pages are DMA'able in Etrax, so put all in the DMA'able zone */
173
174 zones_size[0] = ((unsigned long)high_memory - PAGE_OFFSET) >> PAGE_SHIFT;
175
176 for (i = 1; i < MAX_NR_ZONES; i++)
177 zones_size[i] = 0;
178
179 /* Use free_area_init_node instead of free_area_init, because the former
180 * is designed for systems where the DRAM starts at an address substantially
181 * higher than 0, like us (we start at PAGE_OFFSET). This saves space in the
182 * mem_map page array.
183 */
184
185 free_area_init_node(0, zones_size, PAGE_OFFSET >> PAGE_SHIFT, 0);
186}
187
188/* Initialize remaps of some I/O-ports. It is important that this
189 * is called before any driver is initialized.
190 */
191
192static int
193__init init_ioremap(void)
194{
195
196 /* Give the external I/O-port addresses their values */
197
198#ifdef CONFIG_CRIS_LOW_MAP
199 /* Simply a linear map (see the KSEG map above in paging_init) */
200 port_cse1_addr = (volatile unsigned long *)(MEM_CSE1_START |
201 MEM_NON_CACHEABLE);
202 port_csp0_addr = (volatile unsigned long *)(MEM_CSP0_START |
203 MEM_NON_CACHEABLE);
204 port_csp4_addr = (volatile unsigned long *)(MEM_CSP4_START |
205 MEM_NON_CACHEABLE);
206#else
207 /* Note that nothing blows up just because we do this remapping
208 * it's ok even if the ports are not used or connected
209 * to anything (or connected to a non-I/O thing) */
210 port_cse1_addr = (volatile unsigned long *)
211 ioremap((unsigned long)(MEM_CSE1_START | MEM_NON_CACHEABLE), 16);
212 port_csp0_addr = (volatile unsigned long *)
213 ioremap((unsigned long)(MEM_CSP0_START | MEM_NON_CACHEABLE), 16);
214 port_csp4_addr = (volatile unsigned long *)
215 ioremap((unsigned long)(MEM_CSP4_START | MEM_NON_CACHEABLE), 16);
216#endif
217 return 0;
218}
219
220__initcall(init_ioremap);
221
222/* Helper function for the two below */
223
224static inline void
225flush_etrax_cacherange(void *startadr, int length)
226{
227 /* CACHED_BOOTROM is mapped to the boot-rom area (cached) which
228 * we can use to get fast dummy-reads of cachelines
229 */
230
231 volatile short *flushadr = (volatile short *)(((unsigned long)startadr & ~PAGE_MASK) |
232 CACHED_BOOTROM);
233
234 length = length > 8192 ? 8192 : length; /* No need to flush more than cache size */
235
236 while(length > 0) {
237 *flushadr; /* dummy read to flush */
238 flushadr += (32/sizeof(short)); /* a cacheline is 32 bytes */
239 length -= 32;
240 }
241}
242
243/* Due to a bug in Etrax100(LX) all versions, receiving DMA buffers
244 * will occasionally corrupt certain CPU writes if the DMA buffers
245 * happen to be hot in the cache.
246 *
247 * As a workaround, we have to flush the relevant parts of the cache
248 * before (re) inserting any receiving descriptor into the DMA HW.
249 */
250
251void
252prepare_rx_descriptor(struct etrax_dma_descr *desc)
253{
254 flush_etrax_cacherange((void *)desc->buf, desc->sw_len ? desc->sw_len : 65536);
255}
256
257/* Do the same thing but flush the entire cache */
258
259void
260flush_etrax_cache(void)
261{
262 flush_etrax_cacherange(0, 8192);
263}