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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /arch/arm/mach-socfpga/self-refresh.S
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/arm/mach-socfpga/self-refresh.S')
-rw-r--r--arch/arm/mach-socfpga/self-refresh.S125
1 files changed, 125 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 0000000000..649f277905
--- /dev/null
+++ b/arch/arm/mach-socfpga/self-refresh.S
@@ -0,0 +1,125 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2014-2015 Altera Corporation. All rights reserved.
+ */
+#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