[U-Boot,v3,2/2] x86: Introduce minimal PMU driver for Intel MID platforms

diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index 0ee13b1eb1..c00687a20a 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -54,6 +54,7 @@  enum {
 	X86_NONE,
 	X86_SYSCON_ME,		/* Intel Management Engine */
 	X86_SYSCON_PINCONF,	/* Intel x86 pin configuration */
+	X86_SYSCON_PMU,		/* Power Management Unit */
 	X86_SYSCON_SCU,		/* System Controller Unit */
 };
 
diff --git a/arch/x86/include/asm/pmu.h b/arch/x86/include/asm/pmu.h
new file mode 100644
index 0000000000..96b968ff8f
--- /dev/null
+++ b/arch/x86/include/asm/pmu.h
@@ -0,0 +1,11 @@ 
+/*
+ * Copyright (c) 2017 Intel Corporation
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+#ifndef _X86_ASM_PMU_IPC_H_
+#define _X86_ASM_PMU_IPC_H_
+
+int pmu_turn_power(unsigned int lss, bool on);
+
+#endif	/* _X86_ASM_PMU_IPC_H_ */
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 320e45e4a0..d1ad37af64 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -31,6 +31,7 @@  obj-y	+= pinctrl_ich6.o
 obj-y	+= pirq_routing.o
 obj-y	+= relocate.o
 obj-y += physmem.o
+obj-$(CONFIG_INTEL_MID) += pmu.o
 obj-$(CONFIG_X86_RAMTEST) += ramtest.o
 obj-$(CONFIG_INTEL_MID) += scu.o
 obj-y	+= sections.o
diff --git a/arch/x86/lib/pmu.c b/arch/x86/lib/pmu.c
new file mode 100644
index 0000000000..4ceab8dc64
--- /dev/null
+++ b/arch/x86/lib/pmu.c
@@ -0,0 +1,117 @@ 
+/*
+ * Copyright (c) 2017 Intel Corporation
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+#include <common.h>
+#include <dm.h>
+#include <regmap.h>
+#include <syscon.h>
+#include <asm/cpu.h>
+#include <asm/pmu.h>
+#include <linux/errno.h>
+#include <linux/io.h>
+
+/* Registers */
+struct pmu_regs {
+	u32	sts;
+	u32	cmd;
+	u32	ics;
+	u32	reserved;
+	u32	wkc[4];
+	u32	wks[4];
+	u32	ssc[4];
+	u32	sss[4];
+};
+
+/* Bits in PMU_REGS_STS */
+#define PMU_REGS_STS_BUSY		(1 << 8)
+
+struct pmu_mid {
+	struct pmu_regs *regs;
+};
+
+static int pmu_read_status(struct pmu_regs *regs)
+{
+	int retry = 500000;
+	u32 val;
+
+	do {
+		val = readl(&regs->sts);
+		if (!(val & PMU_REGS_STS_BUSY))
+			return 0;
+
+		udelay(1);
+	} while (--retry);
+
+	printf("WARNING: PMU still busy\n");
+	return -EBUSY;
+}
+
+static int pmu_power_lss(struct pmu_regs *regs, unsigned int lss, bool on)
+{
+	unsigned int offset = (lss * 2) / 32;
+	unsigned int shift = (lss * 2) % 32;
+	u32 ssc;
+	int ret;
+
+	/* Check PMU status */
+	ret = pmu_read_status(regs);
+	if (ret)
+		return ret;
+
+	/* Read PMU values */
+	ssc = readl(&regs->sss[offset]);
+
+	/* Modify PMU values */
+	if (on)
+		ssc &= ~(0x3 << shift);		/* D0 */
+	else
+		ssc |= 0x3 << shift;		/* D3hot */
+
+	/* Write modified PMU values */
+	writel(ssc, &regs->ssc[offset]);
+
+	/* Update modified PMU values */
+	writel(0x00002201, &regs->cmd);
+
+	/* Check PMU status */
+	return pmu_read_status(regs);
+}
+
+int pmu_turn_power(unsigned int lss, bool on)
+{
+	struct pmu_mid *pmu;
+	struct udevice *dev;
+	int ret;
+
+	ret = syscon_get_by_driver_data(X86_SYSCON_PMU, &dev);
+	if (ret)
+		return ret;
+
+	pmu = dev_get_priv(dev);
+
+	return pmu_power_lss(pmu->regs, lss, on);
+}
+
+static int pmu_mid_probe(struct udevice *dev)
+{
+	struct pmu_mid *pmu = dev_get_priv(dev);
+
+	pmu->regs = syscon_get_first_range(X86_SYSCON_PMU);
+
+	return 0;
+}
+
+static const struct udevice_id pmu_mid_match[] = {
+	{ .compatible = "intel,pmu-mid", .data = X86_SYSCON_PMU },
+	{ /* sentinel */ }
+};
+
+U_BOOT_DRIVER(intel_mid_pmu) = {
+	.name		= "pmu_mid",
+	.id		= UCLASS_SYSCON,
+	.of_match	= pmu_mid_match,
+	.probe		= pmu_mid_probe,
+	.priv_auto_alloc_size = sizeof(struct pmu_mid),
+};