[PATCH v2 2/2] socfpga: support suspend to ram

atull at opensource.altera.com
2014-10-01T19:38:24Z

From: Alan Tull <atull@opensource.altera.com>

Add code that requests that the sdr controller go into
self-refresh mode. This code is run from ocram.

This patch assumes that u-boot has already configured sdr:
sdr.ctrlcfg.lowpwreq.selfrfshmask = 3
sdr.ctrlcfg.lowpwrtiming.clkdisablecycles = 8
sdr.ctrlcfg.dramtiming4.selfrfshexit = 512

How to suspend to ram:
$ echo enabled > \
/sys/devices/soc/ffc02000.serial0/tty/ttyS0/power/wakeup

$ echo -n mem > /sys/power/state

Signed-off-by: Alan Tull <atull@opensource.altera.com>

v2: use Generic on-chip SRAM driver to allocate ocram
rm fncpy_align since generic allocator handles alignment
check __arm_ioremap_exec return code
check for NULL pointers
add a comment regarding sdram controller configuration
---
arch/arm/mach-socfpga/Kconfig | 1 +
arch/arm/mach-socfpga/Makefile | 1 +
arch/arm/mach-socfpga/core.h | 6 +-
arch/arm/mach-socfpga/platsmp.c | 4 +-
arch/arm/mach-socfpga/pm.c | 147 +++++++++++++++++++++++++++++++
arch/arm/mach-socfpga/self-refresh.S | 157 ++++++++++++++++++++++++++++++++++
arch/arm/mach-socfpga/socfpga.c | 10 +++
7 files changed, 323 insertions(+), 3 deletions(-)
create mode 100644 arch/arm/mach-socfpga/pm.c
create mode 100644 arch/arm/mach-socfpga/self-refresh.S

diff --git a/arch/arm/mach-socfpga/Kconfig b/arch/arm/mach-socfpga/Kconfig
index b5f8d75..81449da 100644
--- a/arch/arm/mach-socfpga/Kconfig
+++ b/arch/arm/mach-socfpga/Kconfig
@@ -4,6 +4,7 @@ config ARCH_SOCFPGA
select ARM_GIC
select CACHE_L2X0
select DW_APB_TIMER_OF
+ select GENERIC_ALLOCATOR
select GPIO_PL061 if GPIOLIB
select HAVE_ARM_SCU
select HAVE_ARM_TWD if SMP
diff --git a/arch/arm/mach-socfpga/Makefile b/arch/arm/mach-socfpga/Makefile
index 6dd7a93..0591927 100644
--- a/arch/arm/mach-socfpga/Makefile
+++ b/arch/arm/mach-socfpga/Makefile
@@ -4,3 +4,4 @@

obj-y := socfpga.o
obj-$(CONFIG_SMP) += headsmp.o platsmp.o
+obj-$(CONFIG_SUSPEND) += pm.o self-refresh.o
diff --git a/arch/arm/mach-socfpga/core.h b/arch/arm/mach-socfpga/core.h
index 953a9c0..211adfd 100644
--- a/arch/arm/mach-socfpga/core.h
+++ b/arch/arm/mach-socfpga/core.h
@@ -21,7 +21,7 @@
#define __MACH_CORE_H

#define SOCFPGA_RSTMGR_CTRL 0x04
-#define SOCFPGA_RSTMGR_MODMPURST 0x10
+#define SOCFPGA_RSTMGR_MPUMODRST 0x10
#define SOCFPGA_RSTMGR_MODPERRST 0x14
#define SOCFPGA_RSTMGR_BRGMODRST 0x1c

@@ -39,6 +39,7 @@ extern void socfpga_sysmgr_init(void);

extern void __iomem *sys_manager_base_addr;
extern void __iomem *rst_manager_base_addr;
+extern void __iomem *sdr_ctl_base_addr;

extern struct smp_operations socfpga_smp_ops;
extern char secondary_trampoline, secondary_trampoline_end;
@@ -47,4 +48,7 @@ extern unsigned long cpu1start_addr;

#define SOCFPGA_SCU_VIRT_BASE 0xfffec000

+u32 socfpga_sdram_self_refresh(u32 sdr_base, u32 scu_base);
+extern unsigned int socfpga_sdram_self_refresh_sz;
+
#endif
diff --git a/arch/arm/mach-socfpga/platsmp.c b/arch/arm/mach-socfpga/platsmp.c
index 97907dd..4093852 100644
--- a/arch/arm/mach-socfpga/platsmp.c
+++ b/arch/arm/mach-socfpga/platsmp.c
@@ -36,7 +36,7 @@ static int socfpga_boot_secondary(unsigned int cpu, struct task_struct *idle)
if (cpu1start_addr) {
/* This will put CPU #1 into reset. */
__raw_writel(RSTMGR_MPUMODRST_CPU1,
- rst_manager_base_addr + SOCFPGA_RSTMGR_MODMPURST);
+ rst_manager_base_addr + SOCFPGA_RSTMGR_MPUMODRST);

memcpy(phys_to_virt(0), &secondary_trampoline, trampoline_size);

@@ -49,7 +49,7 @@ static int socfpga_boot_secondary(unsigned int cpu, struct task_struct *idle)

/* This will release CPU #1 out of reset. */
__raw_writel(0,
- rst_manager_base_addr + SOCFPGA_RSTMGR_MODMPURST);
+ rst_manager_base_addr + SOCFPGA_RSTMGR_MPUMODRST);
}

return 0;
diff --git a/arch/arm/mach-socfpga/pm.c b/arch/arm/mach-socfpga/pm.c
new file mode 100644
index 0000000..912aab8
--- /dev/null
+++ b/arch/arm/mach-socfpga/pm.c
@@ -0,0 +1,147 @@
+/*
+ * arch/arm/mach-socfpga/pm.c
+ *
+ * Copyright (C) 2014 Altera Corporation. All rights reserved.
+ *
+ * with code from pm-imx6.c
+ * Copyright 2011-2014 Freescale Semiconductor, Inc.
+ * Copyright 2011 Linaro Ltd.
+ *
+ * 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/bitops.h>
+#include <linux/genalloc.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/of_platform.h>
+#include <linux/suspend.h>
+#include <asm/suspend.h>
+#include <asm/fncpy.h>
+#include "core.h"
+
+/* Pointer to function copied to ocram */
+static u32 (*socfpga_sdram_self_refresh_in_ocram)(u32 sdr_base, u32 scu_base);
+
+static int socfpga_setup_ocram_self_refresh(void)
+{
+ struct platform_device *pdev;
+ phys_addr_t ocram_pbase;
+ struct device_node *np;
+ struct gen_pool *ocram_pool;
+ unsigned long ocram_base;
+ void __iomem *suspend_ocram_base;
+ int ret = 0;
+
+ np = of_find_compatible_node(NULL, NULL, "mmio-sram");
+ if (!np) {
+ pr_err("%s: Unable to find mmio-sram in dtb\n", __func__);
+ return 0;
+ }
+
+ pdev = of_find_device_by_node(np);
+ if (!pdev) {
+ pr_warn("%s: failed to find ocram device!\n", __func__);
+ ret = -ENODEV;
+ goto put_node;
+ }
+
+ ocram_pool = dev_get_gen_pool(&pdev->dev);
+ if (!ocram_pool) {
+ pr_warn("%s: ocram pool unavailable!\n", __func__);
+ ret = -ENODEV;
+ goto put_node;
+ }
+
+ ocram_base = gen_pool_alloc(ocram_pool, socfpga_sdram_self_refresh_sz);
+ if (!ocram_base) {
+ pr_warn("%s: unable to alloc ocram!\n", __func__);
+ ret = -ENOMEM;
+ goto put_node;
+ }
+
+ ocram_pbase = gen_pool_virt_to_phys(ocram_pool, ocram_base);
+
+ suspend_ocram_base = __arm_ioremap_exec(ocram_pbase,
+ socfpga_sdram_self_refresh_sz,
+ false);
+ if (!suspend_ocram_base) {
+ pr_warn("%s: __arm_ioremap_exec failed!\n", __func__);
+ ret = -ENOMEM;
+ goto put_node;
+ }
+
+ /* Copy the code that puts DDR in self refresh to ocram */
+ socfpga_sdram_self_refresh_in_ocram =
+ (void *)fncpy(suspend_ocram_base,
+ &socfpga_sdram_self_refresh,
+ socfpga_sdram_self_refresh_sz);
+
+ WARN(!socfpga_sdram_self_refresh_in_ocram,
+ "could not copy function to ocram");
+ if (!socfpga_sdram_self_refresh_in_ocram)
+ ret = -EFAULT;
+
+put_node:
+ of_node_put(np);
+
+ return ret;
+}
+
+static int socfpga_pm_suspend(unsigned long arg)
+{
+ u32 ret;
+
+ if (!sdr_ctl_base_addr || !socfpga_scu_base_addr)
+ return -EFAULT;
+
+ ret = socfpga_sdram_self_refresh_in_ocram(
+ (u32)sdr_ctl_base_addr, (u32)socfpga_scu_base_addr);
+
+ pr_debug("%s self-refresh loops request=%d exit=%d\n", __func__,
+ ret & 0xffff, (ret >> 16) & 0xffff);
+
+ return 0;
+}
+
+static int socfpga_pm_enter(suspend_state_t state)
+{
+ switch (state) {
+ case PM_SUSPEND_STANDBY:
+ case PM_SUSPEND_MEM:
+ outer_disable();
+ cpu_suspend(0, socfpga_pm_suspend);
+ outer_resume();
+ break;
+ default:
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static const struct platform_suspend_ops socfpga_pm_ops = {
+ .valid = suspend_valid_only_mem,
+ .enter = socfpga_pm_enter,
+};
+
+static int __init socfpga_pm_init(void)
+{
+ if (socfpga_setup_ocram_self_refresh())
+ return -EFAULT;
+
+ suspend_set_ops(&socfpga_pm_ops);
+ pr_info("SoCFPGA initialized for DDR self-refresh during suspend.\n");
+
+ return 0;
+}
+arch_initcall(socfpga_pm_init);
diff --git a/arch/arm/mach-socfpga/self-refresh.S b/arch/arm/mach-socfpga/self-refresh.S
new file mode 100644
index 0000000..93962d4
--- /dev/null
+++ b/arch/arm/mach-socfpga/self-refresh.S
@@ -0,0 +1,157 @@
+/*
+ * Copyright (C) 2014 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 SOCFPGA_SCU_CTRL_OFFS 0
+#define SCU_STANDBY_ENA 0x20
+#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 the bootloader has already
+ * properly configured the sdram controller:
+ *
+ * sdr.ctrlcfg.lowpwreq.selfrfshmask = 3
+ * sdr.ctrlcfg.lowpwrtiming.clkdisablecycles = 8
+ * sdr.ctrlcfg.dramtiming4.selfrfshexit = 512
+ */
+
+ .arch armv7-a
+ .text
+ .align 3
+
+ /*
+ * socfpga_sdram_self_refresh
+ *
+ * r0 : sdr_ctl_base_addr
+ * r1 : socfpga_scu_base_addr
+ * r2 : temp storage of register values
+ * r3 : loop counter
+ * r4 : temp storage of return value
+ *
+ * return value: lower 16 bits: loop count going into self refresh
+ * upper 16 bits: loop count exiting self refresh
+ */
+ENTRY(socfpga_sdram_self_refresh)
+ stmfd sp!, {r4}
+
+ /*
+ * Enable SCU (snoop) standby mode.
+ *
+ * From the ARM Cortex-A9 MPCore Technical Reference Manual:
+ * "When set, SCU CLK is turned off when all processors are in WFI
+ * mode, there is no pending request on the ACP (if implemented), and
+ * there is no remaining activity in the SCU."
+ */
+ ldr r2, [r1, #SOCFPGA_SCU_CTRL_OFFS]
+ orr r2, r2, #SCU_STANDBY_ENA
+ str r2, [r1, #SOCFPGA_SCU_CTRL_OFFS]
+
+ /* 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 r4, 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 r4, r4, 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
+
+ /* Disable SCU standby mode */
+ ldr r2, [r1, #SOCFPGA_SCU_CTRL_OFFS]
+ bic r2, r2, #SCU_STANDBY_ENA
+ str r2, [r1, #SOCFPGA_SCU_CTRL_OFFS]
+
+ mov r0, r4 @ return value
+ ldmfd sp!, {r4}
+ bx lr @ return
+
+ENDPROC(socfpga_sdram_self_refresh)
+ENTRY(socfpga_sdram_self_refresh_sz)
+ .word . - socfpga_sdram_self_refresh
diff --git a/arch/arm/mach-socfpga/socfpga.c b/arch/arm/mach-socfpga/socfpga.c
index adbf383..34b4cc5 100644
--- a/arch/arm/mach-socfpga/socfpga.c
+++ b/arch/arm/mach-socfpga/socfpga.c
@@ -30,6 +30,7 @@ void __iomem *socfpga_scu_base_addr = ((void __iomem *)(SOCFPGA_SCU_VIRT_BASE));
void __iomem *sys_manager_base_addr;
void __iomem *rst_manager_base_addr;
unsigned long cpu1start_addr;
+void __iomem *sdr_ctl_base_addr;

static struct map_desc scu_io_desc __initdata = {
.virtual = SOCFPGA_SCU_VIRT_BASE,
@@ -77,6 +78,15 @@ void __init socfpga_sysmgr_init(void)

np = of_find_compatible_node(NULL, NULL, "altr,rst-mgr");
rst_manager_base_addr = of_iomap(np, 0);
+
+ np = of_find_compatible_node(NULL, NULL, "altr,sdr-ctl");
+ if (!np) {
+ pr_err("SOCFPGA: Unable to find sdr-ctl\n");
+ return;
+ }
+
+ sdr_ctl_base_addr = of_iomap(np, 0);
+ WARN_ON(!sdr_ctl_base_addr);
}

static void __init socfpga_init_irq(void)
--
1.7.9.5