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eaad2db0 AV |
1 | /* |
2 | * arch/arm/mach-at91/pm_slow_clock.S | |
3 | * | |
4 | * Copyright (C) 2006 Savin Zlobec | |
5 | * | |
6 | * AT91SAM9 support: | |
7 | * Copyright (C) 2007 Anti Sullin <anti.sullin@artecdesign.ee | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License version 2 as | |
11 | * published by the Free Software Foundation. | |
12 | * | |
13 | */ | |
14 | ||
15 | #include <linux/linkage.h> | |
2edb90ae | 16 | #include <linux/clk/at91_pmc.h> |
eaad2db0 | 17 | #include <mach/hardware.h> |
f363c407 | 18 | #include <mach/at91_ramc.h> |
eaad2db0 | 19 | |
eaad2db0 AV |
20 | /* |
21 | * When SLOWDOWN_MASTER_CLOCK is defined we will also slow down the Master | |
22 | * clock during suspend by adjusting its prescalar and divisor. | |
23 | * NOTE: This hasn't been shown to be stable on SAM9s; and on the RM9200 there | |
24 | * are errata regarding adjusting the prescalar and divisor. | |
25 | */ | |
26 | #undef SLOWDOWN_MASTER_CLOCK | |
27 | ||
8ff12ad3 JCPV |
28 | pmc .req r0 |
29 | sdramc .req r1 | |
30 | ramc1 .req r2 | |
fb7e197b JCPV |
31 | memctrl .req r3 |
32 | tmp1 .req r4 | |
33 | tmp2 .req r5 | |
eaad2db0 AV |
34 | |
35 | /* | |
36 | * Wait until master clock is ready (after switching master clock source) | |
37 | */ | |
38 | .macro wait_mckrdy | |
ad4a38d2 | 39 | 1: ldr tmp1, [pmc, #AT91_PMC_SR] |
0dcfed14 | 40 | tst tmp1, #AT91_PMC_MCKRDY |
eaad2db0 | 41 | beq 1b |
eaad2db0 AV |
42 | .endm |
43 | ||
44 | /* | |
45 | * Wait until master oscillator has stabilized. | |
46 | */ | |
47 | .macro wait_moscrdy | |
ad4a38d2 | 48 | 1: ldr tmp1, [pmc, #AT91_PMC_SR] |
0dcfed14 | 49 | tst tmp1, #AT91_PMC_MOSCS |
eaad2db0 | 50 | beq 1b |
eaad2db0 AV |
51 | .endm |
52 | ||
53 | /* | |
54 | * Wait until PLLA has locked. | |
55 | */ | |
56 | .macro wait_pllalock | |
ad4a38d2 | 57 | 1: ldr tmp1, [pmc, #AT91_PMC_SR] |
0dcfed14 | 58 | tst tmp1, #AT91_PMC_LOCKA |
eaad2db0 | 59 | beq 1b |
eaad2db0 AV |
60 | .endm |
61 | ||
62 | /* | |
63 | * Wait until PLLB has locked. | |
64 | */ | |
65 | .macro wait_pllblock | |
ad4a38d2 | 66 | 1: ldr tmp1, [pmc, #AT91_PMC_SR] |
0dcfed14 | 67 | tst tmp1, #AT91_PMC_LOCKB |
eaad2db0 | 68 | beq 1b |
eaad2db0 AV |
69 | .endm |
70 | ||
71 | .text | |
72 | ||
fb7e197b JCPV |
73 | /* void at91_slow_clock(void __iomem *pmc, void __iomem *sdramc, |
74 | * void __iomem *ramc1, int memctrl) | |
75 | */ | |
eaad2db0 AV |
76 | ENTRY(at91_slow_clock) |
77 | /* Save registers on stack */ | |
fb7e197b | 78 | stmfd sp!, {r4 - r12, lr} |
eaad2db0 AV |
79 | |
80 | /* | |
81 | * Register usage: | |
8ff12ad3 JCPV |
82 | * R0 = Base address of AT91_PMC |
83 | * R1 = Base address of RAM Controller (SDRAM, DDRSDR, or AT91_SYS) | |
84 | * R2 = Base address of second RAM Controller or 0 if not present | |
fb7e197b | 85 | * R3 = Memory controller |
eaad2db0 | 86 | * R4 = temporary register |
fb7e197b | 87 | * R5 = temporary register |
eaad2db0 | 88 | */ |
eaad2db0 AV |
89 | |
90 | /* Drain write buffer */ | |
0dcfed14 JCPV |
91 | mov tmp1, #0 |
92 | mcr p15, 0, tmp1, c7, c10, 4 | |
eaad2db0 | 93 | |
fb7e197b JCPV |
94 | cmp memctrl, #AT91_MEMCTRL_MC |
95 | bne ddr_sr_enable | |
96 | ||
97 | /* | |
98 | * at91rm9200 Memory controller | |
99 | */ | |
eaad2db0 | 100 | /* Put SDRAM in self-refresh mode */ |
0dcfed14 | 101 | mov tmp1, #1 |
1a269ade | 102 | str tmp1, [sdramc, #AT91RM9200_SDRAMC_SRR] |
fb7e197b JCPV |
103 | b sdr_sr_done |
104 | ||
105 | /* | |
106 | * DDRSDR Memory controller | |
107 | */ | |
108 | ddr_sr_enable: | |
109 | cmp memctrl, #AT91_MEMCTRL_DDRSDR | |
110 | bne sdr_sr_enable | |
eaad2db0 | 111 | |
7dca3343 | 112 | /* prepare for DDRAM self-refresh mode */ |
0dcfed14 JCPV |
113 | ldr tmp1, [sdramc, #AT91_DDRSDRC_LPR] |
114 | str tmp1, .saved_sam9_lpr | |
115 | bic tmp1, #AT91_DDRSDRC_LPCB | |
116 | orr tmp1, #AT91_DDRSDRC_LPCB_SELF_REFRESH | |
7dca3343 NF |
117 | |
118 | /* figure out if we use the second ram controller */ | |
0dcfed14 JCPV |
119 | cmp ramc1, #0 |
120 | ldrne tmp2, [ramc1, #AT91_DDRSDRC_LPR] | |
121 | strne tmp2, .saved_sam9_lpr1 | |
122 | bicne tmp2, #AT91_DDRSDRC_LPCB | |
123 | orrne tmp2, #AT91_DDRSDRC_LPCB_SELF_REFRESH | |
7dca3343 NF |
124 | |
125 | /* Enable DDRAM self-refresh mode */ | |
0dcfed14 JCPV |
126 | str tmp1, [sdramc, #AT91_DDRSDRC_LPR] |
127 | strne tmp2, [ramc1, #AT91_DDRSDRC_LPR] | |
fb7e197b JCPV |
128 | |
129 | b sdr_sr_done | |
130 | ||
131 | /* | |
132 | * SDRAMC Memory controller | |
133 | */ | |
134 | sdr_sr_enable: | |
eaad2db0 | 135 | /* Enable SDRAM self-refresh mode */ |
0dcfed14 JCPV |
136 | ldr tmp1, [sdramc, #AT91_SDRAMC_LPR] |
137 | str tmp1, .saved_sam9_lpr | |
eaad2db0 | 138 | |
0dcfed14 JCPV |
139 | bic tmp1, #AT91_SDRAMC_LPCB |
140 | orr tmp1, #AT91_SDRAMC_LPCB_SELF_REFRESH | |
141 | str tmp1, [sdramc, #AT91_SDRAMC_LPR] | |
eaad2db0 | 142 | |
fb7e197b | 143 | sdr_sr_done: |
eaad2db0 | 144 | /* Save Master clock setting */ |
b5514952 | 145 | ldr tmp1, [pmc, #AT91_PMC_MCKR] |
0dcfed14 | 146 | str tmp1, .saved_mckr |
eaad2db0 AV |
147 | |
148 | /* | |
149 | * Set the Master clock source to slow clock | |
150 | */ | |
0dcfed14 | 151 | bic tmp1, tmp1, #AT91_PMC_CSS |
b5514952 | 152 | str tmp1, [pmc, #AT91_PMC_MCKR] |
eaad2db0 AV |
153 | |
154 | wait_mckrdy | |
155 | ||
156 | #ifdef SLOWDOWN_MASTER_CLOCK | |
157 | /* | |
158 | * Set the Master Clock PRES and MDIV fields. | |
159 | * | |
160 | * See AT91RM9200 errata #27 and #28 for details. | |
161 | */ | |
0dcfed14 | 162 | mov tmp1, #0 |
b5514952 | 163 | str tmp1, [pmc, #AT91_PMC_MCKR] |
eaad2db0 AV |
164 | |
165 | wait_mckrdy | |
166 | #endif | |
167 | ||
168 | /* Save PLLA setting and disable it */ | |
b5514952 | 169 | ldr tmp1, [pmc, #AT91_CKGR_PLLAR] |
0dcfed14 | 170 | str tmp1, .saved_pllar |
eaad2db0 | 171 | |
0dcfed14 JCPV |
172 | mov tmp1, #AT91_PMC_PLLCOUNT |
173 | orr tmp1, tmp1, #(1 << 29) /* bit 29 always set */ | |
b5514952 | 174 | str tmp1, [pmc, #AT91_CKGR_PLLAR] |
eaad2db0 | 175 | |
eaad2db0 | 176 | /* Save PLLB setting and disable it */ |
b5514952 | 177 | ldr tmp1, [pmc, #AT91_CKGR_PLLBR] |
0dcfed14 | 178 | str tmp1, .saved_pllbr |
eaad2db0 | 179 | |
0dcfed14 | 180 | mov tmp1, #AT91_PMC_PLLCOUNT |
b5514952 | 181 | str tmp1, [pmc, #AT91_CKGR_PLLBR] |
eaad2db0 | 182 | |
eaad2db0 | 183 | /* Turn off the main oscillator */ |
b5514952 | 184 | ldr tmp1, [pmc, #AT91_CKGR_MOR] |
0dcfed14 | 185 | bic tmp1, tmp1, #AT91_PMC_MOSCEN |
b5514952 | 186 | str tmp1, [pmc, #AT91_CKGR_MOR] |
eaad2db0 AV |
187 | |
188 | /* Wait for interrupt */ | |
0dcfed14 | 189 | mcr p15, 0, tmp1, c7, c0, 4 |
eaad2db0 AV |
190 | |
191 | /* Turn on the main oscillator */ | |
b5514952 | 192 | ldr tmp1, [pmc, #AT91_CKGR_MOR] |
0dcfed14 | 193 | orr tmp1, tmp1, #AT91_PMC_MOSCEN |
b5514952 | 194 | str tmp1, [pmc, #AT91_CKGR_MOR] |
eaad2db0 AV |
195 | |
196 | wait_moscrdy | |
197 | ||
198 | /* Restore PLLB setting */ | |
0dcfed14 | 199 | ldr tmp1, .saved_pllbr |
b5514952 | 200 | str tmp1, [pmc, #AT91_CKGR_PLLBR] |
eaad2db0 | 201 | |
0dcfed14 | 202 | tst tmp1, #(AT91_PMC_MUL & 0xff0000) |
9823f1a8 | 203 | bne 1f |
0dcfed14 | 204 | tst tmp1, #(AT91_PMC_MUL & ~0xff0000) |
9823f1a8 AL |
205 | beq 2f |
206 | 1: | |
eaad2db0 | 207 | wait_pllblock |
9823f1a8 | 208 | 2: |
eaad2db0 AV |
209 | |
210 | /* Restore PLLA setting */ | |
0dcfed14 | 211 | ldr tmp1, .saved_pllar |
b5514952 | 212 | str tmp1, [pmc, #AT91_CKGR_PLLAR] |
eaad2db0 | 213 | |
0dcfed14 | 214 | tst tmp1, #(AT91_PMC_MUL & 0xff0000) |
9823f1a8 | 215 | bne 3f |
0dcfed14 | 216 | tst tmp1, #(AT91_PMC_MUL & ~0xff0000) |
9823f1a8 AL |
217 | beq 4f |
218 | 3: | |
eaad2db0 | 219 | wait_pllalock |
9823f1a8 | 220 | 4: |
eaad2db0 AV |
221 | |
222 | #ifdef SLOWDOWN_MASTER_CLOCK | |
223 | /* | |
224 | * First set PRES if it was not 0, | |
225 | * than set CSS and MDIV fields. | |
226 | * | |
227 | * See AT91RM9200 errata #27 and #28 for details. | |
228 | */ | |
0dcfed14 JCPV |
229 | ldr tmp1, .saved_mckr |
230 | tst tmp1, #AT91_PMC_PRES | |
eaad2db0 | 231 | beq 2f |
0dcfed14 | 232 | and tmp1, tmp1, #AT91_PMC_PRES |
b5514952 | 233 | str tmp1, [pmc, #AT91_PMC_MCKR] |
eaad2db0 AV |
234 | |
235 | wait_mckrdy | |
236 | #endif | |
237 | ||
238 | /* | |
239 | * Restore master clock setting | |
240 | */ | |
0dcfed14 | 241 | 2: ldr tmp1, .saved_mckr |
b5514952 | 242 | str tmp1, [pmc, #AT91_PMC_MCKR] |
eaad2db0 AV |
243 | |
244 | wait_mckrdy | |
245 | ||
fb7e197b JCPV |
246 | /* |
247 | * at91rm9200 Memory controller | |
248 | * Do nothing - self-refresh is automatically disabled. | |
249 | */ | |
250 | cmp memctrl, #AT91_MEMCTRL_MC | |
251 | beq ram_restored | |
252 | ||
253 | /* | |
254 | * DDRSDR Memory controller | |
255 | */ | |
256 | cmp memctrl, #AT91_MEMCTRL_DDRSDR | |
257 | bne sdr_en_restore | |
7dca3343 | 258 | /* Restore LPR on AT91 with DDRAM */ |
0dcfed14 JCPV |
259 | ldr tmp1, .saved_sam9_lpr |
260 | str tmp1, [sdramc, #AT91_DDRSDRC_LPR] | |
7dca3343 NF |
261 | |
262 | /* if we use the second ram controller */ | |
0dcfed14 JCPV |
263 | cmp ramc1, #0 |
264 | ldrne tmp2, .saved_sam9_lpr1 | |
265 | strne tmp2, [ramc1, #AT91_DDRSDRC_LPR] | |
7dca3343 | 266 | |
fb7e197b JCPV |
267 | b ram_restored |
268 | ||
269 | /* | |
270 | * SDRAMC Memory controller | |
271 | */ | |
272 | sdr_en_restore: | |
7dca3343 | 273 | /* Restore LPR on AT91 with SDRAM */ |
0dcfed14 JCPV |
274 | ldr tmp1, .saved_sam9_lpr |
275 | str tmp1, [sdramc, #AT91_SDRAMC_LPR] | |
eaad2db0 | 276 | |
fb7e197b | 277 | ram_restored: |
eaad2db0 | 278 | /* Restore registers, and return */ |
fb7e197b | 279 | ldmfd sp!, {r4 - r12, pc} |
eaad2db0 AV |
280 | |
281 | ||
282 | .saved_mckr: | |
283 | .word 0 | |
284 | ||
285 | .saved_pllar: | |
286 | .word 0 | |
287 | ||
288 | .saved_pllbr: | |
289 | .word 0 | |
290 | ||
291 | .saved_sam9_lpr: | |
292 | .word 0 | |
293 | ||
7dca3343 NF |
294 | .saved_sam9_lpr1: |
295 | .word 0 | |
296 | ||
eaad2db0 AV |
297 | ENTRY(at91_slow_clock_sz) |
298 | .word .-at91_slow_clock |