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authorKevin Hilman <khilman@linaro.org>2015-06-25 04:32:13 (GMT)
committerKevin Hilman <khilman@linaro.org>2015-06-25 04:32:13 (GMT)
commit03fa626774a30145bdb97ce1bc909a0cfd419ce6 (patch)
treea0d66f91d4a983b94f6d74b7b03b5c9e00697499 /arch/arm/mach-socfpga/self-refresh.S
parent8d2977bf36bf6fc66d0c8e64263711cc2f0c1e4b (diff)
parent2879e43f09122f8b3ef5456e3d7e48716b086e60 (diff)
downloadlinux-03fa626774a30145bdb97ce1bc909a0cfd419ce6.tar.xz
Merge tag 'armsoc-soc' into test-merge
ARM: SoC: platform support for v4.2 Our SoC branch usually contains expanded support for new SoCs and other core platform code. Some highlights from this round: - sunxi: SMP support for A23 SoC - socpga: big-endian support - pxa: conversion to common clock framework - bcm: SMP support for BCM63138 - imx: support new I.MX7D SoC - zte: basic support for ZX296702 SoC Conflicts: arch/arm/mach-socfpga/core.h Trivial remove/remove conflict with our cleanup branch. Resolution: remove both sides # gpg: Signature made Wed Jun 24 21:32:12 2015 PDT using RSA key ID D3FBC665 # gpg: Good signature from "Kevin Hilman <khilman@deeprootsystems.com>" # gpg: aka "Kevin Hilman <khilman@linaro.org>" # gpg: aka "Kevin Hilman <khilman@kernel.org>" # Conflicts: # arch/arm/mach-socfpga/core.h
Diffstat (limited to 'arch/arm/mach-socfpga/self-refresh.S')
-rw-r--r--arch/arm/mach-socfpga/self-refresh.S136
1 files changed, 136 insertions, 0 deletions
diff --git a/arch/arm/mach-socfpga/self-refresh.S b/arch/arm/mach-socfpga/self-refresh.S
new file mode 100644
index 0000000..f2d7f88
--- /dev/null
+++ b/arch/arm/mach-socfpga/self-refresh.S
@@ -0,0 +1,136 @@
+/*
+ * 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