Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 859 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/prm44xx.c b/arch/arm/mach-omap2/prm44xx.c
new file mode 100644
index 0000000000..25093c1e5b
--- /dev/null
+++ b/arch/arm/mach-omap2/prm44xx.c
@@ -0,0 +1,859 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * OMAP4 PRM module functions
+ *
+ * Copyright (C) 2011-2012 Texas Instruments, Inc.
+ * Copyright (C) 2010 Nokia Corporation
+ * Benoît Cousson
+ * Paul Walmsley
+ * Rajendra Nayak <rnayak@ti.com>
+ */
+
+#include <linux/cpu_pm.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/of_irq.h>
+#include <linux/of.h>
+
+#include "soc.h"
+#include "iomap.h"
+#include "common.h"
+#include "vp.h"
+#include "prm44xx.h"
+#include "prcm43xx.h"
+#include "prm-regbits-44xx.h"
+#include "prcm44xx.h"
+#include "prminst44xx.h"
+#include "powerdomain.h"
+#include "pm.h"
+
+/* Static data */
+
+static void omap44xx_prm_read_pending_irqs(unsigned long *events);
+static void omap44xx_prm_ocp_barrier(void);
+static void omap44xx_prm_save_and_clear_irqen(u32 *saved_mask);
+static void omap44xx_prm_restore_irqen(u32 *saved_mask);
+static void omap44xx_prm_reconfigure_io_chain(void);
+
+static const struct omap_prcm_irq omap4_prcm_irqs[] = {
+	OMAP_PRCM_IRQ("io",     9,      1),
+};
+
+static struct omap_prcm_irq_setup omap4_prcm_irq_setup = {
+	.ack			= OMAP4_PRM_IRQSTATUS_MPU_OFFSET,
+	.mask			= OMAP4_PRM_IRQENABLE_MPU_OFFSET,
+	.pm_ctrl		= OMAP4_PRM_IO_PMCTRL_OFFSET,
+	.nr_regs		= 2,
+	.irqs			= omap4_prcm_irqs,
+	.nr_irqs		= ARRAY_SIZE(omap4_prcm_irqs),
+	.read_pending_irqs	= &omap44xx_prm_read_pending_irqs,
+	.ocp_barrier		= &omap44xx_prm_ocp_barrier,
+	.save_and_clear_irqen	= &omap44xx_prm_save_and_clear_irqen,
+	.restore_irqen		= &omap44xx_prm_restore_irqen,
+	.reconfigure_io_chain	= &omap44xx_prm_reconfigure_io_chain,
+};
+
+struct omap_prm_irq_context {
+	unsigned long irq_enable;
+	unsigned long pm_ctrl;
+};
+
+static struct omap_prm_irq_context omap_prm_context;
+
+/*
+ * omap44xx_prm_reset_src_map - map from bits in the PRM_RSTST
+ *   hardware register (which are specific to OMAP44xx SoCs) to reset
+ *   source ID bit shifts (which is an OMAP SoC-independent
+ *   enumeration)
+ */
+static struct prm_reset_src_map omap44xx_prm_reset_src_map[] = {
+	{ OMAP4430_GLOBAL_WARM_SW_RST_SHIFT,
+	  OMAP_GLOBAL_WARM_RST_SRC_ID_SHIFT },
+	{ OMAP4430_GLOBAL_COLD_RST_SHIFT,
+	  OMAP_GLOBAL_COLD_RST_SRC_ID_SHIFT },
+	{ OMAP4430_MPU_SECURITY_VIOL_RST_SHIFT,
+	  OMAP_SECU_VIOL_RST_SRC_ID_SHIFT },
+	{ OMAP4430_MPU_WDT_RST_SHIFT, OMAP_MPU_WD_RST_SRC_ID_SHIFT },
+	{ OMAP4430_SECURE_WDT_RST_SHIFT, OMAP_SECU_WD_RST_SRC_ID_SHIFT },
+	{ OMAP4430_EXTERNAL_WARM_RST_SHIFT, OMAP_EXTWARM_RST_SRC_ID_SHIFT },
+	{ OMAP4430_VDD_MPU_VOLT_MGR_RST_SHIFT,
+	  OMAP_VDD_MPU_VM_RST_SRC_ID_SHIFT },
+	{ OMAP4430_VDD_IVA_VOLT_MGR_RST_SHIFT,
+	  OMAP_VDD_IVA_VM_RST_SRC_ID_SHIFT },
+	{ OMAP4430_VDD_CORE_VOLT_MGR_RST_SHIFT,
+	  OMAP_VDD_CORE_VM_RST_SRC_ID_SHIFT },
+	{ OMAP4430_ICEPICK_RST_SHIFT, OMAP_ICEPICK_RST_SRC_ID_SHIFT },
+	{ OMAP4430_C2C_RST_SHIFT, OMAP_C2C_RST_SRC_ID_SHIFT },
+	{ -1, -1 },
+};
+
+/* PRM low-level functions */
+
+/* Read a register in a CM/PRM instance in the PRM module */
+static u32 omap4_prm_read_inst_reg(s16 inst, u16 reg)
+{
+	return readl_relaxed(prm_base.va + inst + reg);
+}
+
+/* Write into a register in a CM/PRM instance in the PRM module */
+static void omap4_prm_write_inst_reg(u32 val, s16 inst, u16 reg)
+{
+	writel_relaxed(val, prm_base.va + inst + reg);
+}
+
+/* Read-modify-write a register in a PRM module. Caller must lock */
+static u32 omap4_prm_rmw_inst_reg_bits(u32 mask, u32 bits, s16 inst, s16 reg)
+{
+	u32 v;
+
+	v = omap4_prm_read_inst_reg(inst, reg);
+	v &= ~mask;
+	v |= bits;
+	omap4_prm_write_inst_reg(v, inst, reg);
+
+	return v;
+}
+
+/* PRM VP */
+
+/*
+ * struct omap4_vp - OMAP4 VP register access description.
+ * @irqstatus_mpu: offset to IRQSTATUS_MPU register for VP
+ * @tranxdone_status: VP_TRANXDONE_ST bitmask in PRM_IRQSTATUS_MPU reg
+ */
+struct omap4_vp {
+	u32 irqstatus_mpu;
+	u32 tranxdone_status;
+};
+
+static struct omap4_vp omap4_vp[] = {
+	[OMAP4_VP_VDD_MPU_ID] = {
+		.irqstatus_mpu = OMAP4_PRM_IRQSTATUS_MPU_2_OFFSET,
+		.tranxdone_status = OMAP4430_VP_MPU_TRANXDONE_ST_MASK,
+	},
+	[OMAP4_VP_VDD_IVA_ID] = {
+		.irqstatus_mpu = OMAP4_PRM_IRQSTATUS_MPU_OFFSET,
+		.tranxdone_status = OMAP4430_VP_IVA_TRANXDONE_ST_MASK,
+	},
+	[OMAP4_VP_VDD_CORE_ID] = {
+		.irqstatus_mpu = OMAP4_PRM_IRQSTATUS_MPU_OFFSET,
+		.tranxdone_status = OMAP4430_VP_CORE_TRANXDONE_ST_MASK,
+	},
+};
+
+static u32 omap4_prm_vp_check_txdone(u8 vp_id)
+{
+	struct omap4_vp *vp = &omap4_vp[vp_id];
+	u32 irqstatus;
+
+	irqstatus = omap4_prminst_read_inst_reg(OMAP4430_PRM_PARTITION,
+						OMAP4430_PRM_OCP_SOCKET_INST,
+						vp->irqstatus_mpu);
+	return irqstatus & vp->tranxdone_status;
+}
+
+static void omap4_prm_vp_clear_txdone(u8 vp_id)
+{
+	struct omap4_vp *vp = &omap4_vp[vp_id];
+
+	omap4_prminst_write_inst_reg(vp->tranxdone_status,
+				     OMAP4430_PRM_PARTITION,
+				     OMAP4430_PRM_OCP_SOCKET_INST,
+				     vp->irqstatus_mpu);
+};
+
+u32 omap4_prm_vcvp_read(u8 offset)
+{
+	s32 inst = omap4_prmst_get_prm_dev_inst();
+
+	if (inst == PRM_INSTANCE_UNKNOWN)
+		return 0;
+
+	return omap4_prminst_read_inst_reg(OMAP4430_PRM_PARTITION,
+					   inst, offset);
+}
+
+void omap4_prm_vcvp_write(u32 val, u8 offset)
+{
+	s32 inst = omap4_prmst_get_prm_dev_inst();
+
+	if (inst == PRM_INSTANCE_UNKNOWN)
+		return;
+
+	omap4_prminst_write_inst_reg(val, OMAP4430_PRM_PARTITION,
+				     inst, offset);
+}
+
+u32 omap4_prm_vcvp_rmw(u32 mask, u32 bits, u8 offset)
+{
+	s32 inst = omap4_prmst_get_prm_dev_inst();
+
+	if (inst == PRM_INSTANCE_UNKNOWN)
+		return 0;
+
+	return omap4_prminst_rmw_inst_reg_bits(mask, bits,
+					       OMAP4430_PRM_PARTITION,
+					       inst,
+					       offset);
+}
+
+static inline u32 _read_pending_irq_reg(u16 irqen_offs, u16 irqst_offs)
+{
+	u32 mask, st;
+
+	/* XXX read mask from RAM? */
+	mask = omap4_prm_read_inst_reg(OMAP4430_PRM_OCP_SOCKET_INST,
+				       irqen_offs);
+	st = omap4_prm_read_inst_reg(OMAP4430_PRM_OCP_SOCKET_INST, irqst_offs);
+
+	return mask & st;
+}
+
+/**
+ * omap44xx_prm_read_pending_irqs - read pending PRM MPU IRQs into @events
+ * @events: ptr to two consecutive u32s, preallocated by caller
+ *
+ * Read PRM_IRQSTATUS_MPU* bits, AND'ed with the currently-enabled PRM
+ * MPU IRQs, and store the result into the two u32s pointed to by @events.
+ * No return value.
+ */
+static void omap44xx_prm_read_pending_irqs(unsigned long *events)
+{
+	int i;
+
+	for (i = 0; i < omap4_prcm_irq_setup.nr_regs; i++)
+		events[i] = _read_pending_irq_reg(omap4_prcm_irq_setup.mask +
+				i * 4, omap4_prcm_irq_setup.ack + i * 4);
+}
+
+/**
+ * omap44xx_prm_ocp_barrier - force buffered MPU writes to the PRM to complete
+ *
+ * Force any buffered writes to the PRM IP block to complete.  Needed
+ * by the PRM IRQ handler, which reads and writes directly to the IP
+ * block, to avoid race conditions after acknowledging or clearing IRQ
+ * bits.  No return value.
+ */
+static void omap44xx_prm_ocp_barrier(void)
+{
+	omap4_prm_read_inst_reg(OMAP4430_PRM_OCP_SOCKET_INST,
+				OMAP4_REVISION_PRM_OFFSET);
+}
+
+/**
+ * omap44xx_prm_save_and_clear_irqen - save/clear PRM_IRQENABLE_MPU* regs
+ * @saved_mask: ptr to a u32 array to save IRQENABLE bits
+ *
+ * Save the PRM_IRQENABLE_MPU and PRM_IRQENABLE_MPU_2 registers to
+ * @saved_mask.  @saved_mask must be allocated by the caller.
+ * Intended to be used in the PRM interrupt handler suspend callback.
+ * The OCP barrier is needed to ensure the write to disable PRM
+ * interrupts reaches the PRM before returning; otherwise, spurious
+ * interrupts might occur.  No return value.
+ */
+static void omap44xx_prm_save_and_clear_irqen(u32 *saved_mask)
+{
+	int i;
+	u16 reg;
+
+	for (i = 0; i < omap4_prcm_irq_setup.nr_regs; i++) {
+		reg = omap4_prcm_irq_setup.mask + i * 4;
+
+		saved_mask[i] =
+			omap4_prm_read_inst_reg(OMAP4430_PRM_OCP_SOCKET_INST,
+						reg);
+		omap4_prm_write_inst_reg(0, OMAP4430_PRM_OCP_SOCKET_INST, reg);
+	}
+
+	/* OCP barrier */
+	omap4_prm_read_inst_reg(OMAP4430_PRM_OCP_SOCKET_INST,
+				OMAP4_REVISION_PRM_OFFSET);
+}
+
+/**
+ * omap44xx_prm_restore_irqen - set PRM_IRQENABLE_MPU* registers from args
+ * @saved_mask: ptr to a u32 array of IRQENABLE bits saved previously
+ *
+ * Restore the PRM_IRQENABLE_MPU and PRM_IRQENABLE_MPU_2 registers from
+ * @saved_mask.  Intended to be used in the PRM interrupt handler resume
+ * callback to restore values saved by omap44xx_prm_save_and_clear_irqen().
+ * No OCP barrier should be needed here; any pending PRM interrupts will fire
+ * once the writes reach the PRM.  No return value.
+ */
+static void omap44xx_prm_restore_irqen(u32 *saved_mask)
+{
+	int i;
+
+	for (i = 0; i < omap4_prcm_irq_setup.nr_regs; i++)
+		omap4_prm_write_inst_reg(saved_mask[i],
+					 OMAP4430_PRM_OCP_SOCKET_INST,
+					 omap4_prcm_irq_setup.mask + i * 4);
+}
+
+/**
+ * omap44xx_prm_reconfigure_io_chain - clear latches and reconfigure I/O chain
+ *
+ * Clear any previously-latched I/O wakeup events and ensure that the
+ * I/O wakeup gates are aligned with the current mux settings.  Works
+ * by asserting WUCLKIN, waiting for WUCLKOUT to be asserted, and then
+ * deasserting WUCLKIN and waiting for WUCLKOUT to be deasserted.
+ * No return value. XXX Are the final two steps necessary?
+ */
+static void omap44xx_prm_reconfigure_io_chain(void)
+{
+	int i = 0;
+	s32 inst = omap4_prmst_get_prm_dev_inst();
+
+	if (inst == PRM_INSTANCE_UNKNOWN)
+		return;
+
+	/* Trigger WUCLKIN enable */
+	omap4_prm_rmw_inst_reg_bits(OMAP4430_WUCLK_CTRL_MASK,
+				    OMAP4430_WUCLK_CTRL_MASK,
+				    inst,
+				    omap4_prcm_irq_setup.pm_ctrl);
+	omap_test_timeout(
+		(((omap4_prm_read_inst_reg(inst,
+					   omap4_prcm_irq_setup.pm_ctrl) &
+		   OMAP4430_WUCLK_STATUS_MASK) >>
+		  OMAP4430_WUCLK_STATUS_SHIFT) == 1),
+		MAX_IOPAD_LATCH_TIME, i);
+	if (i == MAX_IOPAD_LATCH_TIME)
+		pr_warn("PRM: I/O chain clock line assertion timed out\n");
+
+	/* Trigger WUCLKIN disable */
+	omap4_prm_rmw_inst_reg_bits(OMAP4430_WUCLK_CTRL_MASK, 0x0,
+				    inst,
+				    omap4_prcm_irq_setup.pm_ctrl);
+	omap_test_timeout(
+		(((omap4_prm_read_inst_reg(inst,
+					   omap4_prcm_irq_setup.pm_ctrl) &
+		   OMAP4430_WUCLK_STATUS_MASK) >>
+		  OMAP4430_WUCLK_STATUS_SHIFT) == 0),
+		MAX_IOPAD_LATCH_TIME, i);
+	if (i == MAX_IOPAD_LATCH_TIME)
+		pr_warn("PRM: I/O chain clock line deassertion timed out\n");
+
+	return;
+}
+
+/**
+ * omap44xx_prm_enable_io_wakeup - enable wakeup events from I/O wakeup latches
+ *
+ * Activates the I/O wakeup event latches and allows events logged by
+ * those latches to signal a wakeup event to the PRCM.  For I/O wakeups
+ * to occur, WAKEUPENABLE bits must be set in the pad mux registers, and
+ * omap44xx_prm_reconfigure_io_chain() must be called.  No return value.
+ */
+static void omap44xx_prm_enable_io_wakeup(void)
+{
+	s32 inst = omap4_prmst_get_prm_dev_inst();
+
+	if (inst == PRM_INSTANCE_UNKNOWN)
+		return;
+
+	omap4_prm_rmw_inst_reg_bits(OMAP4430_GLOBAL_WUEN_MASK,
+				    OMAP4430_GLOBAL_WUEN_MASK,
+				    inst,
+				    omap4_prcm_irq_setup.pm_ctrl);
+}
+
+/**
+ * omap44xx_prm_read_reset_sources - return the last SoC reset source
+ *
+ * Return a u32 representing the last reset sources of the SoC.  The
+ * returned reset source bits are standardized across OMAP SoCs.
+ */
+static u32 omap44xx_prm_read_reset_sources(void)
+{
+	struct prm_reset_src_map *p;
+	u32 r = 0;
+	u32 v;
+	s32 inst = omap4_prmst_get_prm_dev_inst();
+
+	if (inst == PRM_INSTANCE_UNKNOWN)
+		return 0;
+
+
+	v = omap4_prm_read_inst_reg(inst,
+				    OMAP4_RM_RSTST);
+
+	p = omap44xx_prm_reset_src_map;
+	while (p->reg_shift >= 0 && p->std_shift >= 0) {
+		if (v & (1 << p->reg_shift))
+			r |= 1 << p->std_shift;
+		p++;
+	}
+
+	return r;
+}
+
+/**
+ * omap44xx_prm_was_any_context_lost_old - was module hardware context lost?
+ * @part: PRM partition ID (e.g., OMAP4430_PRM_PARTITION)
+ * @inst: PRM instance offset (e.g., OMAP4430_PRM_MPU_INST)
+ * @idx: CONTEXT register offset
+ *
+ * Return 1 if any bits were set in the *_CONTEXT_* register
+ * identified by (@part, @inst, @idx), which means that some context
+ * was lost for that module; otherwise, return 0.
+ */
+static bool omap44xx_prm_was_any_context_lost_old(u8 part, s16 inst, u16 idx)
+{
+	return (omap4_prminst_read_inst_reg(part, inst, idx)) ? 1 : 0;
+}
+
+/**
+ * omap44xx_prm_clear_context_lost_flags_old - clear context loss flags
+ * @part: PRM partition ID (e.g., OMAP4430_PRM_PARTITION)
+ * @inst: PRM instance offset (e.g., OMAP4430_PRM_MPU_INST)
+ * @idx: CONTEXT register offset
+ *
+ * Clear hardware context loss bits for the module identified by
+ * (@part, @inst, @idx).  No return value.  XXX Writes to reserved bits;
+ * is there a way to avoid this?
+ */
+static void omap44xx_prm_clear_context_loss_flags_old(u8 part, s16 inst,
+						      u16 idx)
+{
+	omap4_prminst_write_inst_reg(0xffffffff, part, inst, idx);
+}
+
+/* Powerdomain low-level functions */
+
+static int omap4_pwrdm_set_next_pwrst(struct powerdomain *pwrdm, u8 pwrst)
+{
+	omap4_prminst_rmw_inst_reg_bits(OMAP_POWERSTATE_MASK,
+					(pwrst << OMAP_POWERSTATE_SHIFT),
+					pwrdm->prcm_partition,
+					pwrdm->prcm_offs, OMAP4_PM_PWSTCTRL);
+	return 0;
+}
+
+static int omap4_pwrdm_read_next_pwrst(struct powerdomain *pwrdm)
+{
+	u32 v;
+
+	v = omap4_prminst_read_inst_reg(pwrdm->prcm_partition, pwrdm->prcm_offs,
+					OMAP4_PM_PWSTCTRL);
+	v &= OMAP_POWERSTATE_MASK;
+	v >>= OMAP_POWERSTATE_SHIFT;
+
+	return v;
+}
+
+static int omap4_pwrdm_read_pwrst(struct powerdomain *pwrdm)
+{
+	u32 v;
+
+	v = omap4_prminst_read_inst_reg(pwrdm->prcm_partition, pwrdm->prcm_offs,
+					OMAP4_PM_PWSTST);
+	v &= OMAP_POWERSTATEST_MASK;
+	v >>= OMAP_POWERSTATEST_SHIFT;
+
+	return v;
+}
+
+static int omap4_pwrdm_read_prev_pwrst(struct powerdomain *pwrdm)
+{
+	u32 v;
+
+	v = omap4_prminst_read_inst_reg(pwrdm->prcm_partition, pwrdm->prcm_offs,
+					OMAP4_PM_PWSTST);
+	v &= OMAP4430_LASTPOWERSTATEENTERED_MASK;
+	v >>= OMAP4430_LASTPOWERSTATEENTERED_SHIFT;
+
+	return v;
+}
+
+static int omap4_pwrdm_set_lowpwrstchange(struct powerdomain *pwrdm)
+{
+	omap4_prminst_rmw_inst_reg_bits(OMAP4430_LOWPOWERSTATECHANGE_MASK,
+					(1 << OMAP4430_LOWPOWERSTATECHANGE_SHIFT),
+					pwrdm->prcm_partition,
+					pwrdm->prcm_offs, OMAP4_PM_PWSTCTRL);
+	return 0;
+}
+
+static int omap4_pwrdm_clear_all_prev_pwrst(struct powerdomain *pwrdm)
+{
+	omap4_prminst_rmw_inst_reg_bits(OMAP4430_LASTPOWERSTATEENTERED_MASK,
+					OMAP4430_LASTPOWERSTATEENTERED_MASK,
+					pwrdm->prcm_partition,
+					pwrdm->prcm_offs, OMAP4_PM_PWSTST);
+	return 0;
+}
+
+static int omap4_pwrdm_set_logic_retst(struct powerdomain *pwrdm, u8 pwrst)
+{
+	u32 v;
+
+	v = pwrst << __ffs(OMAP4430_LOGICRETSTATE_MASK);
+	omap4_prminst_rmw_inst_reg_bits(OMAP4430_LOGICRETSTATE_MASK, v,
+					pwrdm->prcm_partition, pwrdm->prcm_offs,
+					OMAP4_PM_PWSTCTRL);
+
+	return 0;
+}
+
+static int omap4_pwrdm_set_mem_onst(struct powerdomain *pwrdm, u8 bank,
+				    u8 pwrst)
+{
+	u32 m;
+
+	m = omap2_pwrdm_get_mem_bank_onstate_mask(bank);
+
+	omap4_prminst_rmw_inst_reg_bits(m, (pwrst << __ffs(m)),
+					pwrdm->prcm_partition, pwrdm->prcm_offs,
+					OMAP4_PM_PWSTCTRL);
+
+	return 0;
+}
+
+static int omap4_pwrdm_set_mem_retst(struct powerdomain *pwrdm, u8 bank,
+				     u8 pwrst)
+{
+	u32 m;
+
+	m = omap2_pwrdm_get_mem_bank_retst_mask(bank);
+
+	omap4_prminst_rmw_inst_reg_bits(m, (pwrst << __ffs(m)),
+					pwrdm->prcm_partition, pwrdm->prcm_offs,
+					OMAP4_PM_PWSTCTRL);
+
+	return 0;
+}
+
+static int omap4_pwrdm_read_logic_pwrst(struct powerdomain *pwrdm)
+{
+	u32 v;
+
+	v = omap4_prminst_read_inst_reg(pwrdm->prcm_partition, pwrdm->prcm_offs,
+					OMAP4_PM_PWSTST);
+	v &= OMAP4430_LOGICSTATEST_MASK;
+	v >>= OMAP4430_LOGICSTATEST_SHIFT;
+
+	return v;
+}
+
+static int omap4_pwrdm_read_logic_retst(struct powerdomain *pwrdm)
+{
+	u32 v;
+
+	v = omap4_prminst_read_inst_reg(pwrdm->prcm_partition, pwrdm->prcm_offs,
+					OMAP4_PM_PWSTCTRL);
+	v &= OMAP4430_LOGICRETSTATE_MASK;
+	v >>= OMAP4430_LOGICRETSTATE_SHIFT;
+
+	return v;
+}
+
+/**
+ * omap4_pwrdm_read_prev_logic_pwrst - read the previous logic powerstate
+ * @pwrdm: struct powerdomain * to read the state for
+ *
+ * Reads the previous logic powerstate for a powerdomain. This
+ * function must determine the previous logic powerstate by first
+ * checking the previous powerstate for the domain. If that was OFF,
+ * then logic has been lost. If previous state was RETENTION, the
+ * function reads the setting for the next retention logic state to
+ * see the actual value.  In every other case, the logic is
+ * retained. Returns either PWRDM_POWER_OFF or PWRDM_POWER_RET
+ * depending whether the logic was retained or not.
+ */
+static int omap4_pwrdm_read_prev_logic_pwrst(struct powerdomain *pwrdm)
+{
+	int state;
+
+	state = omap4_pwrdm_read_prev_pwrst(pwrdm);
+
+	if (state == PWRDM_POWER_OFF)
+		return PWRDM_POWER_OFF;
+
+	if (state != PWRDM_POWER_RET)
+		return PWRDM_POWER_RET;
+
+	return omap4_pwrdm_read_logic_retst(pwrdm);
+}
+
+static int omap4_pwrdm_read_mem_pwrst(struct powerdomain *pwrdm, u8 bank)
+{
+	u32 m, v;
+
+	m = omap2_pwrdm_get_mem_bank_stst_mask(bank);
+
+	v = omap4_prminst_read_inst_reg(pwrdm->prcm_partition, pwrdm->prcm_offs,
+					OMAP4_PM_PWSTST);
+	v &= m;
+	v >>= __ffs(m);
+
+	return v;
+}
+
+static int omap4_pwrdm_read_mem_retst(struct powerdomain *pwrdm, u8 bank)
+{
+	u32 m, v;
+
+	m = omap2_pwrdm_get_mem_bank_retst_mask(bank);
+
+	v = omap4_prminst_read_inst_reg(pwrdm->prcm_partition, pwrdm->prcm_offs,
+					OMAP4_PM_PWSTCTRL);
+	v &= m;
+	v >>= __ffs(m);
+
+	return v;
+}
+
+/**
+ * omap4_pwrdm_read_prev_mem_pwrst - reads the previous memory powerstate
+ * @pwrdm: struct powerdomain * to read mem powerstate for
+ * @bank: memory bank index
+ *
+ * Reads the previous memory powerstate for a powerdomain. This
+ * function must determine the previous memory powerstate by first
+ * checking the previous powerstate for the domain. If that was OFF,
+ * then logic has been lost. If previous state was RETENTION, the
+ * function reads the setting for the next memory retention state to
+ * see the actual value.  In every other case, the logic is
+ * retained. Returns either PWRDM_POWER_OFF or PWRDM_POWER_RET
+ * depending whether logic was retained or not.
+ */
+static int omap4_pwrdm_read_prev_mem_pwrst(struct powerdomain *pwrdm, u8 bank)
+{
+	int state;
+
+	state = omap4_pwrdm_read_prev_pwrst(pwrdm);
+
+	if (state == PWRDM_POWER_OFF)
+		return PWRDM_POWER_OFF;
+
+	if (state != PWRDM_POWER_RET)
+		return PWRDM_POWER_RET;
+
+	return omap4_pwrdm_read_mem_retst(pwrdm, bank);
+}
+
+static int omap4_pwrdm_wait_transition(struct powerdomain *pwrdm)
+{
+	u32 c = 0;
+
+	/*
+	 * REVISIT: pwrdm_wait_transition() may be better implemented
+	 * via a callback and a periodic timer check -- how long do we expect
+	 * powerdomain transitions to take?
+	 */
+
+	/* XXX Is this udelay() value meaningful? */
+	while ((omap4_prminst_read_inst_reg(pwrdm->prcm_partition,
+					    pwrdm->prcm_offs,
+					    OMAP4_PM_PWSTST) &
+		OMAP_INTRANSITION_MASK) &&
+	       (c++ < PWRDM_TRANSITION_BAILOUT))
+		udelay(1);
+
+	if (c > PWRDM_TRANSITION_BAILOUT) {
+		pr_err("powerdomain: %s: waited too long to complete transition\n",
+		       pwrdm->name);
+		return -EAGAIN;
+	}
+
+	pr_debug("powerdomain: completed transition in %d loops\n", c);
+
+	return 0;
+}
+
+static int omap4_check_vcvp(void)
+{
+	if (prm_features & PRM_HAS_VOLTAGE)
+		return 1;
+
+	return 0;
+}
+
+/**
+ * omap4_pwrdm_save_context - Saves the powerdomain state
+ * @pwrdm: pointer to individual powerdomain
+ *
+ * The function saves the powerdomain state control information.
+ * This is needed in rtc+ddr modes where we lose powerdomain context.
+ */
+static void omap4_pwrdm_save_context(struct powerdomain *pwrdm)
+{
+	pwrdm->context = omap4_prminst_read_inst_reg(pwrdm->prcm_partition,
+						     pwrdm->prcm_offs,
+						     pwrdm->pwrstctrl_offs);
+
+	/*
+	 * Do not save LOWPOWERSTATECHANGE, writing a 1 indicates a request,
+	 * reading back a 1 indicates a request in progress.
+	 */
+	pwrdm->context &= ~OMAP4430_LOWPOWERSTATECHANGE_MASK;
+}
+
+/**
+ * omap4_pwrdm_restore_context - Restores the powerdomain state
+ * @pwrdm: pointer to individual powerdomain
+ *
+ * The function restores the powerdomain state control information.
+ * This is needed in rtc+ddr modes where we lose powerdomain context.
+ */
+static void omap4_pwrdm_restore_context(struct powerdomain *pwrdm)
+{
+	int st, ctrl;
+
+	st = omap4_prminst_read_inst_reg(pwrdm->prcm_partition,
+					 pwrdm->prcm_offs,
+					 pwrdm->pwrstctrl_offs);
+
+	omap4_prminst_write_inst_reg(pwrdm->context,
+				     pwrdm->prcm_partition,
+				     pwrdm->prcm_offs,
+				     pwrdm->pwrstctrl_offs);
+
+	/* Make sure we only wait for a transition if there is one */
+	st &= OMAP_POWERSTATEST_MASK;
+	ctrl = OMAP_POWERSTATEST_MASK & pwrdm->context;
+
+	if (st != ctrl)
+		omap4_pwrdm_wait_transition(pwrdm);
+}
+
+struct pwrdm_ops omap4_pwrdm_operations = {
+	.pwrdm_set_next_pwrst	= omap4_pwrdm_set_next_pwrst,
+	.pwrdm_read_next_pwrst	= omap4_pwrdm_read_next_pwrst,
+	.pwrdm_read_pwrst	= omap4_pwrdm_read_pwrst,
+	.pwrdm_read_prev_pwrst	= omap4_pwrdm_read_prev_pwrst,
+	.pwrdm_set_lowpwrstchange	= omap4_pwrdm_set_lowpwrstchange,
+	.pwrdm_clear_all_prev_pwrst	= omap4_pwrdm_clear_all_prev_pwrst,
+	.pwrdm_set_logic_retst	= omap4_pwrdm_set_logic_retst,
+	.pwrdm_read_logic_pwrst	= omap4_pwrdm_read_logic_pwrst,
+	.pwrdm_read_prev_logic_pwrst	= omap4_pwrdm_read_prev_logic_pwrst,
+	.pwrdm_read_logic_retst	= omap4_pwrdm_read_logic_retst,
+	.pwrdm_read_mem_pwrst	= omap4_pwrdm_read_mem_pwrst,
+	.pwrdm_read_mem_retst	= omap4_pwrdm_read_mem_retst,
+	.pwrdm_read_prev_mem_pwrst	= omap4_pwrdm_read_prev_mem_pwrst,
+	.pwrdm_set_mem_onst	= omap4_pwrdm_set_mem_onst,
+	.pwrdm_set_mem_retst	= omap4_pwrdm_set_mem_retst,
+	.pwrdm_wait_transition	= omap4_pwrdm_wait_transition,
+	.pwrdm_has_voltdm	= omap4_check_vcvp,
+	.pwrdm_save_context	= omap4_pwrdm_save_context,
+	.pwrdm_restore_context	= omap4_pwrdm_restore_context,
+};
+
+static int omap44xx_prm_late_init(void);
+
+static void prm_save_context(void)
+{
+	omap_prm_context.irq_enable =
+			omap4_prm_read_inst_reg(AM43XX_PRM_OCP_SOCKET_INST,
+						omap4_prcm_irq_setup.mask);
+
+	omap_prm_context.pm_ctrl =
+			omap4_prm_read_inst_reg(AM43XX_PRM_DEVICE_INST,
+						omap4_prcm_irq_setup.pm_ctrl);
+}
+
+static void prm_restore_context(void)
+{
+	omap4_prm_write_inst_reg(omap_prm_context.irq_enable,
+				 OMAP4430_PRM_OCP_SOCKET_INST,
+				 omap4_prcm_irq_setup.mask);
+
+	omap4_prm_write_inst_reg(omap_prm_context.pm_ctrl,
+				 AM43XX_PRM_DEVICE_INST,
+				 omap4_prcm_irq_setup.pm_ctrl);
+}
+
+static int cpu_notifier(struct notifier_block *nb, unsigned long cmd, void *v)
+{
+	switch (cmd) {
+	case CPU_CLUSTER_PM_ENTER:
+		if (enable_off_mode)
+			prm_save_context();
+		break;
+	case CPU_CLUSTER_PM_EXIT:
+		if (enable_off_mode)
+			prm_restore_context();
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+/*
+ * XXX document
+ */
+static struct prm_ll_data omap44xx_prm_ll_data = {
+	.read_reset_sources = &omap44xx_prm_read_reset_sources,
+	.was_any_context_lost_old = &omap44xx_prm_was_any_context_lost_old,
+	.clear_context_loss_flags_old = &omap44xx_prm_clear_context_loss_flags_old,
+	.late_init = &omap44xx_prm_late_init,
+	.assert_hardreset	= omap4_prminst_assert_hardreset,
+	.deassert_hardreset	= omap4_prminst_deassert_hardreset,
+	.is_hardreset_asserted	= omap4_prminst_is_hardreset_asserted,
+	.reset_system		= omap4_prminst_global_warm_sw_reset,
+	.vp_check_txdone	= omap4_prm_vp_check_txdone,
+	.vp_clear_txdone	= omap4_prm_vp_clear_txdone,
+};
+
+static const struct omap_prcm_init_data *prm_init_data;
+
+int __init omap44xx_prm_init(const struct omap_prcm_init_data *data)
+{
+	static struct notifier_block nb;
+	omap_prm_base_init();
+
+	prm_init_data = data;
+
+	if (data->flags & PRM_HAS_IO_WAKEUP)
+		prm_features |= PRM_HAS_IO_WAKEUP;
+
+	if (data->flags & PRM_HAS_VOLTAGE)
+		prm_features |= PRM_HAS_VOLTAGE;
+
+	omap4_prminst_set_prm_dev_inst(data->device_inst_offset);
+
+	/* Add AM437X specific differences */
+	if (of_device_is_compatible(data->np, "ti,am4-prcm")) {
+		omap4_prcm_irq_setup.nr_irqs = 1;
+		omap4_prcm_irq_setup.nr_regs = 1;
+		omap4_prcm_irq_setup.pm_ctrl = AM43XX_PRM_IO_PMCTRL_OFFSET;
+		omap4_prcm_irq_setup.ack = AM43XX_PRM_IRQSTATUS_MPU_OFFSET;
+		omap4_prcm_irq_setup.mask = AM43XX_PRM_IRQENABLE_MPU_OFFSET;
+	}
+
+	/* Only AM43XX can lose prm context during rtc-ddr suspend */
+	if (soc_is_am43xx()) {
+		nb.notifier_call = cpu_notifier;
+		cpu_pm_register_notifier(&nb);
+	}
+
+	return prm_register(&omap44xx_prm_ll_data);
+}
+
+static int omap44xx_prm_late_init(void)
+{
+	int irq_num;
+
+	if (!(prm_features & PRM_HAS_IO_WAKEUP))
+		return 0;
+
+	irq_num = of_irq_get(prm_init_data->np, 0);
+	if (irq_num == -EPROBE_DEFER)
+		return irq_num;
+
+	omap4_prcm_irq_setup.irq = irq_num;
+
+	omap44xx_prm_enable_io_wakeup();
+
+	return omap_prcm_register_chain_handler(&omap4_prcm_irq_setup);
+}
+
+static void __exit omap44xx_prm_exit(void)
+{
+	prm_unregister(&omap44xx_prm_ll_data);
+}
+__exitcall(omap44xx_prm_exit);