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670c104a TL |
1 | /* |
2 | * linux/arch/arm/mach-omap2/sleep.S | |
3 | * | |
4 | * (C) Copyright 2004 | |
5 | * Texas Instruments, <www.ti.com> | |
6 | * Richard Woodruff <r-woodruff2@ti.com> | |
7 | * | |
1835f1d7 TL |
8 | * (C) Copyright 2006 Nokia Corporation |
9 | * Fixed idle loop sleep | |
10 | * Igor Stoppa <igor.stoppa@nokia.com> | |
11 | * | |
670c104a TL |
12 | * This program is free software; you can redistribute it and/or |
13 | * modify it under the terms of the GNU General Public License as | |
14 | * published by the Free Software Foundation; either version 2 of | |
15 | * the License, or (at your option) any later version. | |
16 | * | |
17 | * This program is distributed in the hope that it will be useful, | |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR /PURPOSE. See the | |
20 | * GNU General Public License for more details. | |
21 | * | |
22 | * You should have received a copy of the GNU General Public License | |
23 | * along with this program; if not, write to the Free Software | |
24 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, | |
25 | * MA 02111-1307 USA | |
26 | */ | |
27 | ||
670c104a TL |
28 | #include <linux/linkage.h> |
29 | #include <asm/assembler.h> | |
a09e64fb | 30 | #include <mach/io.h> |
670c104a | 31 | |
1835f1d7 TL |
32 | #include <mach/omap24xx.h> |
33 | ||
44595982 | 34 | #include "sdrc.h" |
670c104a | 35 | |
44595982 | 36 | /* First address of reserved address space? apparently valid for OMAP2 & 3 */ |
670c104a | 37 | #define A_SDRC0_V (0xC0000000) |
670c104a TL |
38 | |
39 | .text | |
40 | ||
41 | /* | |
42 | * Forces OMAP into idle state | |
43 | * | |
44 | * omap24xx_idle_loop_suspend() - This bit of code just executes the WFI | |
45 | * for normal idles. | |
46 | * | |
47 | * Note: This code get's copied to internal SRAM at boot. When the OMAP | |
48 | * wakes up it continues execution at the point it went to sleep. | |
49 | */ | |
50 | ENTRY(omap24xx_idle_loop_suspend) | |
51 | stmfd sp!, {r0, lr} @ save registers on stack | |
52 | mov r0, #0 @ clear for mcr setup | |
53 | mcr p15, 0, r0, c7, c0, 4 @ wait for interrupt | |
54 | ldmfd sp!, {r0, pc} @ restore regs and return | |
55 | ||
56 | ENTRY(omap24xx_idle_loop_suspend_sz) | |
57 | .word . - omap24xx_idle_loop_suspend | |
58 | ||
59 | /* | |
1835f1d7 | 60 | * omap24xx_cpu_suspend() - Forces OMAP into deep sleep state by completing |
670c104a TL |
61 | * SDRC shutdown then ARM shutdown. Upon wake MPU is back on so just restore |
62 | * SDRC. | |
63 | * | |
64 | * Input: | |
65 | * R0 : DLL ctrl value pre-Sleep | |
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66 | * R1 : SDRC_DLLA_CTRL |
67 | * R2 : SDRC_POWER | |
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68 | * |
69 | * The if the DPLL is going to AutoIdle. It seems like the DPLL may be back on | |
70 | * when we get called, but the DLL probably isn't. We will wait a bit more in | |
71 | * case the DPLL isn't quite there yet. The code will wait on DLL for DDR even | |
72 | * if in unlocked mode. | |
73 | * | |
74 | * For less than 242x-ES2.2 upon wake from a sleep mode where the external | |
75 | * oscillator was stopped, a timing bug exists where a non-stabilized 12MHz | |
76 | * clock can pass into the PRCM can cause problems at DSP and IVA. | |
77 | * To work around this the code will switch to the 32kHz source prior to sleep. | |
78 | * Post sleep we will shift back to using the DPLL. Apparently, | |
79 | * CM_IDLEST_CLKGEN does not reflect the full clock change so you need to wait | |
80 | * 3x12MHz + 3x32kHz clocks for a full switch. | |
81 | * | |
82 | * The DLL load value is not kept in RETENTION or OFF. It needs to be restored | |
83 | * at wake | |
84 | */ | |
85 | ENTRY(omap24xx_cpu_suspend) | |
86 | stmfd sp!, {r0 - r12, lr} @ save registers on stack | |
1835f1d7 | 87 | mov r3, #0x0 @ clear for mcr call |
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88 | mcr p15, 0, r3, c7, c10, 4 @ memory barrier, hope SDR/DDR finished |
89 | nop | |
90 | nop | |
1835f1d7 | 91 | ldr r4, [r2] @ read SDRC_POWER |
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92 | orr r4, r4, #0x40 @ enable self refresh on idle req |
93 | mov r5, #0x2000 @ set delay (DPLL relock + DLL relock) | |
1835f1d7 | 94 | str r4, [r2] @ make it so |
670c104a | 95 | nop |
0dc23d70 | 96 | mcr p15, 0, r3, c7, c0, 4 @ wait for interrupt |
670c104a TL |
97 | nop |
98 | loop: | |
99 | subs r5, r5, #0x1 @ awake, wait just a bit | |
100 | bne loop | |
101 | ||
1835f1d7 | 102 | /* The DPLL has to be on before we take the DDR out of self refresh */ |
670c104a | 103 | bic r4, r4, #0x40 @ now clear self refresh bit. |
1835f1d7 | 104 | str r4, [r2] @ write to SDRC_POWER |
670c104a | 105 | ldr r4, A_SDRC0 @ make a clock happen |
1835f1d7 | 106 | ldr r4, [r4] @ read A_SDRC0 |
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107 | nop @ start auto refresh only after clk ok |
108 | movs r0, r0 @ see if DDR or SDR | |
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109 | strne r0, [r1] @ rewrite DLLA to force DLL reload |
110 | addne r1, r1, #0x8 @ move to DLLB | |
111 | strne r0, [r1] @ rewrite DLLB to force DLL reload | |
112 | ||
113 | mov r5, #0x1000 | |
114 | loop2: | |
115 | subs r5, r5, #0x1 | |
116 | bne loop2 | |
117 | /* resume*/ | |
118 | ldmfd sp!, {r0 - r12, pc} @ restore regs and return | |
119 | ||
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120 | A_SDRC0: |
121 | .word A_SDRC0_V | |
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122 | |
123 | ENTRY(omap24xx_cpu_suspend_sz) | |
124 | .word . - omap24xx_cpu_suspend |