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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 | /* * Copyright (C) 2014-2015 Altera Corporation. All rights reserved. * * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. * * You should have received a copy of the GNU General Public License along with * this program. If not, see <http://www.gnu.org/licenses/>. */ #include <linux/linkage.h> #include <asm/assembler.h> #define MAX_LOOP_COUNT 1000 /* Register offset */ #define SDR_CTRLGRP_LOWPWREQ_ADDR 0x54 #define SDR_CTRLGRP_LOWPWRACK_ADDR 0x58 /* Bitfield positions */ #define SELFRSHREQ_POS 3 #define SELFRSHREQ_MASK 0x8 #define SELFRFSHACK_POS 1 #define SELFRFSHACK_MASK 0x2 /* * This code assumes that when the bootloader configured * the sdram controller for the DDR on the board it * configured the following fields depending on the DDR * vendor/configuration: * * sdr.ctrlcfg.lowpwreq.selfrfshmask * sdr.ctrlcfg.lowpwrtiming.clkdisablecycles * sdr.ctrlcfg.dramtiming4.selfrfshexit */ .arch armv7-a .text .align 3 /* * socfpga_sdram_self_refresh * * r0 : sdr_ctl_base_addr * r1 : temp storage of return value * r2 : temp storage of register values * r3 : loop counter * * return value: lower 16 bits: loop count going into self refresh * upper 16 bits: loop count exiting self refresh */ ENTRY(socfpga_sdram_self_refresh) /* Enable dynamic clock gating in the Power Control Register. */ mrc p15, 0, r2, c15, c0, 0 orr r2, r2, #1 mcr p15, 0, r2, c15, c0, 0 /* Enable self refresh: set sdr.ctrlgrp.lowpwreq.selfrshreq = 1 */ ldr r2, [r0, #SDR_CTRLGRP_LOWPWREQ_ADDR] orr r2, r2, #SELFRSHREQ_MASK str r2, [r0, #SDR_CTRLGRP_LOWPWREQ_ADDR] /* Poll until sdr.ctrlgrp.lowpwrack.selfrfshack == 1 or hit max loops */ mov r3, #0 while_ack_0: ldr r2, [r0, #SDR_CTRLGRP_LOWPWRACK_ADDR] and r2, r2, #SELFRFSHACK_MASK cmp r2, #SELFRFSHACK_MASK beq ack_1 add r3, #1 cmp r3, #MAX_LOOP_COUNT bne while_ack_0 ack_1: mov r1, r3 /* * Execute an ISB instruction to ensure that all of the * CP15 register changes have been committed. */ isb /* * Execute a barrier instruction to ensure that all cache, * TLB and branch predictor maintenance operations issued * by any CPU in the cluster have completed. */ dsb dmb wfi /* Disable self-refresh: set sdr.ctrlgrp.lowpwreq.selfrshreq = 0 */ ldr r2, [r0, #SDR_CTRLGRP_LOWPWREQ_ADDR] bic r2, r2, #SELFRSHREQ_MASK str r2, [r0, #SDR_CTRLGRP_LOWPWREQ_ADDR] /* Poll until sdr.ctrlgrp.lowpwrack.selfrfshack == 0 or hit max loops */ mov r3, #0 while_ack_1: ldr r2, [r0, #SDR_CTRLGRP_LOWPWRACK_ADDR] and r2, r2, #SELFRFSHACK_MASK cmp r2, #SELFRFSHACK_MASK bne ack_0 add r3, #1 cmp r3, #MAX_LOOP_COUNT bne while_ack_1 ack_0: /* * Prepare return value: * Shift loop count for exiting self refresh into upper 16 bits. * Leave loop count for requesting self refresh in lower 16 bits. */ mov r3, r3, lsl #16 add r1, r1, r3 /* Disable dynamic clock gating in the Power Control Register. */ mrc p15, 0, r2, c15, c0, 0 bic r2, r2, #1 mcr p15, 0, r2, c15, c0, 0 mov r0, r1 @ return value bx lr @ return ENDPROC(socfpga_sdram_self_refresh) ENTRY(socfpga_sdram_self_refresh_sz) .word . - socfpga_sdram_self_refresh |