Eric Lee / smarc-uboot

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arch/x86/lib/pmu.c 2.06 KB
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d41ce506b   Eric Lee   Initial Release, ... 
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  /*
   * 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
  ");
  	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),
  };