Initial import

1 files changed, 670 insertions, 0 deletions

diff --git a/arch/arm/mach-mvebu/pmsu.c b/arch/arm/mach-mvebu/pmsu.c
new file mode 100644
index 000000000..4f4e22206
--- /dev/null
+++ b/arch/arm/mach-mvebu/pmsu.c
@@ -0,0 +1,670 @@
+/*
+ * Power Management Service Unit(PMSU) support for Armada 370/XP platforms.
+ *
+ * Copyright (C) 2012 Marvell
+ *
+ * Yehuda Yitschak <yehuday@marvell.com>
+ * Gregory Clement <gregory.clement@free-electrons.com>
+ * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ *
+ * The Armada 370 and Armada XP SOCs have a power management service
+ * unit which is responsible for powering down and waking up CPUs and
+ * other SOC units
+ */
+
+#define pr_fmt(fmt) "mvebu-pmsu: " fmt
+
+#include <linux/clk.h>
+#include <linux/cpu_pm.h>
+#include <linux/cpufreq-dt.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mbus.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/resource.h>
+#include <linux/slab.h>
+#include <linux/smp.h>
+#include <asm/cacheflush.h>
+#include <asm/cp15.h>
+#include <asm/smp_scu.h>
+#include <asm/smp_plat.h>
+#include <asm/suspend.h>
+#include <asm/tlbflush.h>
+#include "common.h"
+
+
+#define PMSU_BASE_OFFSET    0x100
+#define PMSU_REG_SIZE	    0x1000
+
+/* PMSU MP registers */
+#define PMSU_CONTROL_AND_CONFIG(cpu)	    ((cpu * 0x100) + 0x104)
+#define PMSU_CONTROL_AND_CONFIG_DFS_REQ		BIT(18)
+#define PMSU_CONTROL_AND_CONFIG_PWDDN_REQ	BIT(16)
+#define PMSU_CONTROL_AND_CONFIG_L2_PWDDN	BIT(20)
+
+#define PMSU_CPU_POWER_DOWN_CONTROL(cpu)    ((cpu * 0x100) + 0x108)
+
+#define PMSU_CPU_POWER_DOWN_DIS_SNP_Q_SKIP	BIT(0)
+
+#define PMSU_STATUS_AND_MASK(cpu)	    ((cpu * 0x100) + 0x10c)
+#define PMSU_STATUS_AND_MASK_CPU_IDLE_WAIT	BIT(16)
+#define PMSU_STATUS_AND_MASK_SNP_Q_EMPTY_WAIT	BIT(17)
+#define PMSU_STATUS_AND_MASK_IRQ_WAKEUP		BIT(20)
+#define PMSU_STATUS_AND_MASK_FIQ_WAKEUP		BIT(21)
+#define PMSU_STATUS_AND_MASK_DBG_WAKEUP		BIT(22)
+#define PMSU_STATUS_AND_MASK_IRQ_MASK		BIT(24)
+#define PMSU_STATUS_AND_MASK_FIQ_MASK		BIT(25)
+
+#define PMSU_EVENT_STATUS_AND_MASK(cpu)     ((cpu * 0x100) + 0x120)
+#define PMSU_EVENT_STATUS_AND_MASK_DFS_DONE        BIT(1)
+#define PMSU_EVENT_STATUS_AND_MASK_DFS_DONE_MASK   BIT(17)
+
+#define PMSU_BOOT_ADDR_REDIRECT_OFFSET(cpu) ((cpu * 0x100) + 0x124)
+
+/* PMSU fabric registers */
+#define L2C_NFABRIC_PM_CTL		    0x4
+#define L2C_NFABRIC_PM_CTL_PWR_DOWN		BIT(20)
+
+/* PMSU delay registers */
+#define PMSU_POWERDOWN_DELAY		    0xF04
+#define PMSU_POWERDOWN_DELAY_PMU		BIT(1)
+#define PMSU_POWERDOWN_DELAY_MASK		0xFFFE
+#define PMSU_DFLT_ARMADA38X_DELAY	        0x64
+
+/* CA9 MPcore SoC Control registers */
+
+#define MPCORE_RESET_CTL		    0x64
+#define MPCORE_RESET_CTL_L2			BIT(0)
+#define MPCORE_RESET_CTL_DEBUG			BIT(16)
+
+#define SRAM_PHYS_BASE  0xFFFF0000
+#define BOOTROM_BASE    0xFFF00000
+#define BOOTROM_SIZE    0x100000
+
+#define ARMADA_370_CRYPT0_ENG_TARGET   0x9
+#define ARMADA_370_CRYPT0_ENG_ATTR     0x1
+
+extern void ll_disable_coherency(void);
+extern void ll_enable_coherency(void);
+
+extern void armada_370_xp_cpu_resume(void);
+extern void armada_38x_cpu_resume(void);
+
+static phys_addr_t pmsu_mp_phys_base;
+static void __iomem *pmsu_mp_base;
+
+static void *mvebu_cpu_resume;
+
+static const struct of_device_id of_pmsu_table[] = {
+	{ .compatible = "marvell,armada-370-pmsu", },
+	{ .compatible = "marvell,armada-370-xp-pmsu", },
+	{ .compatible = "marvell,armada-380-pmsu", },
+	{ /* end of list */ },
+};
+
+void mvebu_pmsu_set_cpu_boot_addr(int hw_cpu, void *boot_addr)
+{
+	writel(virt_to_phys(boot_addr), pmsu_mp_base +
+		PMSU_BOOT_ADDR_REDIRECT_OFFSET(hw_cpu));
+}
+
+extern unsigned char mvebu_boot_wa_start;
+extern unsigned char mvebu_boot_wa_end;
+
+/*
+ * This function sets up the boot address workaround needed for SMP
+ * boot on Armada 375 Z1 and cpuidle on Armada 370. It unmaps the
+ * BootROM Mbus window, and instead remaps a crypto SRAM into which a
+ * custom piece of code is copied to replace the problematic BootROM.
+ */
+int mvebu_setup_boot_addr_wa(unsigned int crypto_eng_target,
+			     unsigned int crypto_eng_attribute,
+			     phys_addr_t resume_addr_reg)
+{
+	void __iomem *sram_virt_base;
+	u32 code_len = &mvebu_boot_wa_end - &mvebu_boot_wa_start;
+
+	mvebu_mbus_del_window(BOOTROM_BASE, BOOTROM_SIZE);
+	mvebu_mbus_add_window_by_id(crypto_eng_target, crypto_eng_attribute,
+				    SRAM_PHYS_BASE, SZ_64K);
+
+	sram_virt_base = ioremap(SRAM_PHYS_BASE, SZ_64K);
+	if (!sram_virt_base) {
+		pr_err("Unable to map SRAM to setup the boot address WA\n");
+		return -ENOMEM;
+	}
+
+	memcpy(sram_virt_base, &mvebu_boot_wa_start, code_len);
+
+	/*
+	 * The last word of the code copied in SRAM must contain the
+	 * physical base address of the PMSU register. We
+	 * intentionally store this address in the native endianness
+	 * of the system.
+	 */
+	__raw_writel((unsigned long)resume_addr_reg,
+		     sram_virt_base + code_len - 4);
+
+	iounmap(sram_virt_base);
+
+	return 0;
+}
+
+static int __init mvebu_v7_pmsu_init(void)
+{
+	struct device_node *np;
+	struct resource res;
+	int ret = 0;
+
+	np = of_find_matching_node(NULL, of_pmsu_table);
+	if (!np)
+		return 0;
+
+	pr_info("Initializing Power Management Service Unit\n");
+
+	if (of_address_to_resource(np, 0, &res)) {
+		pr_err("unable to get resource\n");
+		ret = -ENOENT;
+		goto out;
+	}
+
+	if (of_device_is_compatible(np, "marvell,armada-370-xp-pmsu")) {
+		pr_warn(FW_WARN "deprecated pmsu binding\n");
+		res.start = res.start - PMSU_BASE_OFFSET;
+		res.end = res.start + PMSU_REG_SIZE - 1;
+	}
+
+	if (!request_mem_region(res.start, resource_size(&res),
+				np->full_name)) {
+		pr_err("unable to request region\n");
+		ret = -EBUSY;
+		goto out;
+	}
+
+	pmsu_mp_phys_base = res.start;
+
+	pmsu_mp_base = ioremap(res.start, resource_size(&res));
+	if (!pmsu_mp_base) {
+		pr_err("unable to map registers\n");
+		release_mem_region(res.start, resource_size(&res));
+		ret = -ENOMEM;
+		goto out;
+	}
+
+ out:
+	of_node_put(np);
+	return ret;
+}
+
+static void mvebu_v7_pmsu_enable_l2_powerdown_onidle(void)
+{
+	u32 reg;
+
+	if (pmsu_mp_base == NULL)
+		return;
+
+	/* Enable L2 & Fabric powerdown in Deep-Idle mode - Fabric */
+	reg = readl(pmsu_mp_base + L2C_NFABRIC_PM_CTL);
+	reg |= L2C_NFABRIC_PM_CTL_PWR_DOWN;
+	writel(reg, pmsu_mp_base + L2C_NFABRIC_PM_CTL);
+}
+
+enum pmsu_idle_prepare_flags {
+	PMSU_PREPARE_NORMAL = 0,
+	PMSU_PREPARE_DEEP_IDLE = BIT(0),
+	PMSU_PREPARE_SNOOP_DISABLE = BIT(1),
+};
+
+/* No locking is needed because we only access per-CPU registers */
+static int mvebu_v7_pmsu_idle_prepare(unsigned long flags)
+{
+	unsigned int hw_cpu = cpu_logical_map(smp_processor_id());
+	u32 reg;
+
+	if (pmsu_mp_base == NULL)
+		return -EINVAL;
+
+	/*
+	 * Adjust the PMSU configuration to wait for WFI signal, enable
+	 * IRQ and FIQ as wakeup events, set wait for snoop queue empty
+	 * indication and mask IRQ and FIQ from CPU
+	 */
+	reg = readl(pmsu_mp_base + PMSU_STATUS_AND_MASK(hw_cpu));
+	reg |= PMSU_STATUS_AND_MASK_CPU_IDLE_WAIT    |
+	       PMSU_STATUS_AND_MASK_IRQ_WAKEUP       |
+	       PMSU_STATUS_AND_MASK_FIQ_WAKEUP       |
+	       PMSU_STATUS_AND_MASK_SNP_Q_EMPTY_WAIT |
+	       PMSU_STATUS_AND_MASK_IRQ_MASK         |
+	       PMSU_STATUS_AND_MASK_FIQ_MASK;
+	writel(reg, pmsu_mp_base + PMSU_STATUS_AND_MASK(hw_cpu));
+
+	reg = readl(pmsu_mp_base + PMSU_CONTROL_AND_CONFIG(hw_cpu));
+	/* ask HW to power down the L2 Cache if needed */
+	if (flags & PMSU_PREPARE_DEEP_IDLE)
+		reg |= PMSU_CONTROL_AND_CONFIG_L2_PWDDN;
+
+	/* request power down */
+	reg |= PMSU_CONTROL_AND_CONFIG_PWDDN_REQ;
+	writel(reg, pmsu_mp_base + PMSU_CONTROL_AND_CONFIG(hw_cpu));
+
+	if (flags & PMSU_PREPARE_SNOOP_DISABLE) {
+		/* Disable snoop disable by HW - SW is taking care of it */
+		reg = readl(pmsu_mp_base + PMSU_CPU_POWER_DOWN_CONTROL(hw_cpu));
+		reg |= PMSU_CPU_POWER_DOWN_DIS_SNP_Q_SKIP;
+		writel(reg, pmsu_mp_base + PMSU_CPU_POWER_DOWN_CONTROL(hw_cpu));
+	}
+
+	return 0;
+}
+
+int armada_370_xp_pmsu_idle_enter(unsigned long deepidle)
+{
+	unsigned long flags = PMSU_PREPARE_SNOOP_DISABLE;
+	int ret;
+
+	if (deepidle)
+		flags |= PMSU_PREPARE_DEEP_IDLE;
+
+	ret = mvebu_v7_pmsu_idle_prepare(flags);
+	if (ret)
+		return ret;
+
+	v7_exit_coherency_flush(all);
+
+	ll_disable_coherency();
+
+	dsb();
+
+	wfi();
+
+	/* If we are here, wfi failed. As processors run out of
+	 * coherency for some time, tlbs might be stale, so flush them
+	 */
+	local_flush_tlb_all();
+
+	ll_enable_coherency();
+
+	/* Test the CR_C bit and set it if it was cleared */
+	asm volatile(
+	"mrc	p15, 0, r0, c1, c0, 0 \n\t"
+	"tst	r0, #(1 << 2) \n\t"
+	"orreq	r0, r0, #(1 << 2) \n\t"
+	"mcreq	p15, 0, r0, c1, c0, 0 \n\t"
+	"isb	"
+	: : : "r0");
+
+	pr_debug("Failed to suspend the system\n");
+
+	return 0;
+}
+
+static int armada_370_xp_cpu_suspend(unsigned long deepidle)
+{
+	return cpu_suspend(deepidle, armada_370_xp_pmsu_idle_enter);
+}
+
+int armada_38x_do_cpu_suspend(unsigned long deepidle)
+{
+	unsigned long flags = 0;
+
+	if (deepidle)
+		flags |= PMSU_PREPARE_DEEP_IDLE;
+
+	mvebu_v7_pmsu_idle_prepare(flags);
+	/*
+	 * Already flushed cache, but do it again as the outer cache
+	 * functions dirty the cache with spinlocks
+	 */
+	v7_exit_coherency_flush(louis);
+
+	scu_power_mode(mvebu_get_scu_base(), SCU_PM_POWEROFF);
+
+	cpu_do_idle();
+
+	return 1;
+}
+
+static int armada_38x_cpu_suspend(unsigned long deepidle)
+{
+	return cpu_suspend(false, armada_38x_do_cpu_suspend);
+}
+
+/* No locking is needed because we only access per-CPU registers */
+void mvebu_v7_pmsu_idle_exit(void)
+{
+	unsigned int hw_cpu = cpu_logical_map(smp_processor_id());
+	u32 reg;
+
+	if (pmsu_mp_base == NULL)
+		return;
+	/* cancel ask HW to power down the L2 Cache if possible */
+	reg = readl(pmsu_mp_base + PMSU_CONTROL_AND_CONFIG(hw_cpu));
+	reg &= ~PMSU_CONTROL_AND_CONFIG_L2_PWDDN;
+	writel(reg, pmsu_mp_base + PMSU_CONTROL_AND_CONFIG(hw_cpu));
+
+	/* cancel Enable wakeup events and mask interrupts */
+	reg = readl(pmsu_mp_base + PMSU_STATUS_AND_MASK(hw_cpu));
+	reg &= ~(PMSU_STATUS_AND_MASK_IRQ_WAKEUP | PMSU_STATUS_AND_MASK_FIQ_WAKEUP);
+	reg &= ~PMSU_STATUS_AND_MASK_CPU_IDLE_WAIT;
+	reg &= ~PMSU_STATUS_AND_MASK_SNP_Q_EMPTY_WAIT;
+	reg &= ~(PMSU_STATUS_AND_MASK_IRQ_MASK | PMSU_STATUS_AND_MASK_FIQ_MASK);
+	writel(reg, pmsu_mp_base + PMSU_STATUS_AND_MASK(hw_cpu));
+}
+
+static int mvebu_v7_cpu_pm_notify(struct notifier_block *self,
+				    unsigned long action, void *hcpu)
+{
+	if (action == CPU_PM_ENTER) {
+		unsigned int hw_cpu = cpu_logical_map(smp_processor_id());
+		mvebu_pmsu_set_cpu_boot_addr(hw_cpu, mvebu_cpu_resume);
+	} else if (action == CPU_PM_EXIT) {
+		mvebu_v7_pmsu_idle_exit();
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block mvebu_v7_cpu_pm_notifier = {
+	.notifier_call = mvebu_v7_cpu_pm_notify,
+};
+
+static struct platform_device mvebu_v7_cpuidle_device;
+
+static __init int armada_370_cpuidle_init(void)
+{
+	struct device_node *np;
+	phys_addr_t redirect_reg;
+
+	np = of_find_compatible_node(NULL, NULL, "marvell,coherency-fabric");
+	if (!np)
+		return -ENODEV;
+	of_node_put(np);
+
+	/*
+	 * On Armada 370, there is "a slow exit process from the deep
+	 * idle state due to heavy L1/L2 cache cleanup operations
+	 * performed by the BootROM software". To avoid this, we
+	 * replace the restart code of the bootrom by a a simple jump
+	 * to the boot address. Then the code located at this boot
+	 * address will take care of the initialization.
+	 */
+	redirect_reg = pmsu_mp_phys_base + PMSU_BOOT_ADDR_REDIRECT_OFFSET(0);
+	mvebu_setup_boot_addr_wa(ARMADA_370_CRYPT0_ENG_TARGET,
+				 ARMADA_370_CRYPT0_ENG_ATTR,
+				 redirect_reg);
+
+	mvebu_cpu_resume = armada_370_xp_cpu_resume;
+	mvebu_v7_cpuidle_device.dev.platform_data = armada_370_xp_cpu_suspend;
+	mvebu_v7_cpuidle_device.name = "cpuidle-armada-370";
+
+	return 0;
+}
+
+static __init int armada_38x_cpuidle_init(void)
+{
+	struct device_node *np;
+	void __iomem *mpsoc_base;
+	u32 reg;
+
+	pr_warn("CPU idle is currently broken on Armada 38x: disabling");
+	return 0;
+
+	np = of_find_compatible_node(NULL, NULL,
+				     "marvell,armada-380-coherency-fabric");
+	if (!np)
+		return -ENODEV;
+	of_node_put(np);
+
+	np = of_find_compatible_node(NULL, NULL,
+				     "marvell,armada-380-mpcore-soc-ctrl");
+	if (!np)
+		return -ENODEV;
+	mpsoc_base = of_iomap(np, 0);
+	BUG_ON(!mpsoc_base);
+	of_node_put(np);
+
+	/* Set up reset mask when powering down the cpus */
+	reg = readl(mpsoc_base + MPCORE_RESET_CTL);
+	reg |= MPCORE_RESET_CTL_L2;
+	reg |= MPCORE_RESET_CTL_DEBUG;
+	writel(reg, mpsoc_base + MPCORE_RESET_CTL);
+	iounmap(mpsoc_base);
+
+	/* Set up delay */
+	reg = readl(pmsu_mp_base + PMSU_POWERDOWN_DELAY);
+	reg &= ~PMSU_POWERDOWN_DELAY_MASK;
+	reg |= PMSU_DFLT_ARMADA38X_DELAY;
+	reg |= PMSU_POWERDOWN_DELAY_PMU;
+	writel(reg, pmsu_mp_base + PMSU_POWERDOWN_DELAY);
+
+	mvebu_cpu_resume = armada_38x_cpu_resume;
+	mvebu_v7_cpuidle_device.dev.platform_data = armada_38x_cpu_suspend;
+	mvebu_v7_cpuidle_device.name = "cpuidle-armada-38x";
+
+	return 0;
+}
+
+static __init int armada_xp_cpuidle_init(void)
+{
+	struct device_node *np;
+
+	np = of_find_compatible_node(NULL, NULL, "marvell,coherency-fabric");
+	if (!np)
+		return -ENODEV;
+	of_node_put(np);
+
+	mvebu_cpu_resume = armada_370_xp_cpu_resume;
+	mvebu_v7_cpuidle_device.dev.platform_data = armada_370_xp_cpu_suspend;
+	mvebu_v7_cpuidle_device.name = "cpuidle-armada-xp";
+
+	return 0;
+}
+
+static int __init mvebu_v7_cpu_pm_init(void)
+{
+	struct device_node *np;
+	int ret;
+
+	np = of_find_matching_node(NULL, of_pmsu_table);
+	if (!np)
+		return 0;
+	of_node_put(np);
+
+	/*
+	 * Currently the CPU idle support for Armada 38x is broken, as
+	 * the CPU hotplug uses some of the CPU idle functions it is
+	 * broken too, so let's disable it
+	 */
+	if (of_machine_is_compatible("marvell,armada380")) {
+		cpu_hotplug_disable();
+		pr_warn("CPU hotplug support is currently broken on Armada 38x: disabling");
+	}
+
+	if (of_machine_is_compatible("marvell,armadaxp"))
+		ret = armada_xp_cpuidle_init();
+	else if (of_machine_is_compatible("marvell,armada370"))
+		ret = armada_370_cpuidle_init();
+	else if (of_machine_is_compatible("marvell,armada380"))
+		ret = armada_38x_cpuidle_init();
+	else
+		return 0;
+
+	if (ret)
+		return ret;
+
+	mvebu_v7_pmsu_enable_l2_powerdown_onidle();
+	if (mvebu_v7_cpuidle_device.name)
+		platform_device_register(&mvebu_v7_cpuidle_device);
+	cpu_pm_register_notifier(&mvebu_v7_cpu_pm_notifier);
+
+	return 0;
+}
+
+arch_initcall(mvebu_v7_cpu_pm_init);
+early_initcall(mvebu_v7_pmsu_init);
+
+static void mvebu_pmsu_dfs_request_local(void *data)
+{
+	u32 reg;
+	u32 cpu = smp_processor_id();
+	unsigned long flags;
+
+	local_irq_save(flags);
+
+	/* Prepare to enter idle */
+	reg = readl(pmsu_mp_base + PMSU_STATUS_AND_MASK(cpu));
+	reg |= PMSU_STATUS_AND_MASK_CPU_IDLE_WAIT |
+	       PMSU_STATUS_AND_MASK_IRQ_MASK     |
+	       PMSU_STATUS_AND_MASK_FIQ_MASK;
+	writel(reg, pmsu_mp_base + PMSU_STATUS_AND_MASK(cpu));
+
+	/* Request the DFS transition */
+	reg = readl(pmsu_mp_base + PMSU_CONTROL_AND_CONFIG(cpu));
+	reg |= PMSU_CONTROL_AND_CONFIG_DFS_REQ;
+	writel(reg, pmsu_mp_base + PMSU_CONTROL_AND_CONFIG(cpu));
+
+	/* The fact of entering idle will trigger the DFS transition */
+	wfi();
+
+	/*
+	 * We're back from idle, the DFS transition has completed,
+	 * clear the idle wait indication.
+	 */
+	reg = readl(pmsu_mp_base + PMSU_STATUS_AND_MASK(cpu));
+	reg &= ~PMSU_STATUS_AND_MASK_CPU_IDLE_WAIT;
+	writel(reg, pmsu_mp_base + PMSU_STATUS_AND_MASK(cpu));
+
+	local_irq_restore(flags);
+}
+
+int mvebu_pmsu_dfs_request(int cpu)
+{
+	unsigned long timeout;
+	int hwcpu = cpu_logical_map(cpu);
+	u32 reg;
+
+	/* Clear any previous DFS DONE event */
+	reg = readl(pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
+	reg &= ~PMSU_EVENT_STATUS_AND_MASK_DFS_DONE;
+	writel(reg, pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
+
+	/* Mask the DFS done interrupt, since we are going to poll */
+	reg = readl(pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
+	reg |= PMSU_EVENT_STATUS_AND_MASK_DFS_DONE_MASK;
+	writel(reg, pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
+
+	/* Trigger the DFS on the appropriate CPU */
+	smp_call_function_single(cpu, mvebu_pmsu_dfs_request_local,
+				 NULL, false);
+
+	/* Poll until the DFS done event is generated */
+	timeout = jiffies + HZ;
+	while (time_before(jiffies, timeout)) {
+		reg = readl(pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
+		if (reg & PMSU_EVENT_STATUS_AND_MASK_DFS_DONE)
+			break;
+		udelay(10);
+	}
+
+	if (time_after(jiffies, timeout))
+		return -ETIME;
+
+	/* Restore the DFS mask to its original state */
+	reg = readl(pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
+	reg &= ~PMSU_EVENT_STATUS_AND_MASK_DFS_DONE_MASK;
+	writel(reg, pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
+
+	return 0;
+}
+
+struct cpufreq_dt_platform_data cpufreq_dt_pd = {
+	.independent_clocks = true,
+};
+
+static int __init armada_xp_pmsu_cpufreq_init(void)
+{
+	struct device_node *np;
+	struct resource res;
+	int ret, cpu;
+
+	if (!of_machine_is_compatible("marvell,armadaxp"))
+		return 0;
+
+	/*
+	 * In order to have proper cpufreq handling, we need to ensure
+	 * that the Device Tree description of the CPU clock includes
+	 * the definition of the PMU DFS registers. If not, we do not
+	 * register the clock notifier and the cpufreq driver. This
+	 * piece of code is only for compatibility with old Device
+	 * Trees.
+	 */
+	np = of_find_compatible_node(NULL, NULL, "marvell,armada-xp-cpu-clock");
+	if (!np)
+		return 0;
+
+	ret = of_address_to_resource(np, 1, &res);
+	if (ret) {
+		pr_warn(FW_WARN "not enabling cpufreq, deprecated armada-xp-cpu-clock binding\n");
+		of_node_put(np);
+		return 0;
+	}
+
+	of_node_put(np);
+
+	/*
+	 * For each CPU, this loop registers the operating points
+	 * supported (which are the nominal CPU frequency and half of
+	 * it), and registers the clock notifier that will take care
+	 * of doing the PMSU part of a frequency transition.
+	 */
+	for_each_possible_cpu(cpu) {
+		struct device *cpu_dev;
+		struct clk *clk;
+		int ret;
+
+		cpu_dev = get_cpu_device(cpu);
+		if (!cpu_dev) {
+			pr_err("Cannot get CPU %d\n", cpu);
+			continue;
+		}
+
+		clk = clk_get(cpu_dev, 0);
+		if (IS_ERR(clk)) {
+			pr_err("Cannot get clock for CPU %d\n", cpu);
+			return PTR_ERR(clk);
+		}
+
+		/*
+		 * In case of a failure of dev_pm_opp_add(), we don't
+		 * bother with cleaning up the registered OPP (there's
+		 * no function to do so), and simply cancel the
+		 * registration of the cpufreq device.
+		 */
+		ret = dev_pm_opp_add(cpu_dev, clk_get_rate(clk), 0);
+		if (ret) {
+			clk_put(clk);
+			return ret;
+		}
+
+		ret = dev_pm_opp_add(cpu_dev, clk_get_rate(clk) / 2, 0);
+		if (ret) {
+			clk_put(clk);
+			return ret;
+		}
+	}
+
+	platform_device_register_data(NULL, "cpufreq-dt", -1,
+				      &cpufreq_dt_pd, sizeof(cpufreq_dt_pd));
+	return 0;
+}
+
+device_initcall(armada_xp_pmsu_cpufreq_init);