3 files changed, 305 insertions, 99 deletions

diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index b1652cab631a..2afe798d1586 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -48,11 +48,6 @@ acpi_handle acpi_get_processor_handle(int cpu)
 
 static int acpi_processor_errata_piix4(struct pci_dev *dev)
 {
-	u8 value1 = 0;
-	u8 value2 = 0;
-	struct pci_dev *ide_dev = NULL, *isa_dev = NULL;
-
-
 	if (!dev)
 		return -EINVAL;
 
@@ -108,16 +103,16 @@ static int acpi_processor_errata_piix4(struct pci_dev *dev)
 		 * each IDE controller's DMA status to make sure we catch all
 		 * DMA activity.
 		 */
-		ide_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
+		dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
 				     PCI_DEVICE_ID_INTEL_82371AB,
 				     PCI_ANY_ID, PCI_ANY_ID, NULL);
-		if (ide_dev) {
-			errata.piix4.bmisx = pci_resource_start(ide_dev, 4);
+		if (dev) {
+			errata.piix4.bmisx = pci_resource_start(dev, 4);
 			if (errata.piix4.bmisx)
-				dev_dbg(&ide_dev->dev,
+				dev_dbg(&dev->dev,
 					"Bus master activity detection (BM-IDE) erratum enabled\n");
 
-			pci_dev_put(ide_dev);
+			pci_dev_put(dev);
 		}
 
 		/*
@@ -129,18 +124,20 @@ static int acpi_processor_errata_piix4(struct pci_dev *dev)
 		 * disable C3 support if this is enabled, as some legacy
 		 * devices won't operate well if fast DMA is disabled.
 		 */
-		isa_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
+		dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
 				     PCI_DEVICE_ID_INTEL_82371AB_0,
 				     PCI_ANY_ID, PCI_ANY_ID, NULL);
-		if (isa_dev) {
-			pci_read_config_byte(isa_dev, 0x76, &value1);
-			pci_read_config_byte(isa_dev, 0x77, &value2);
+		if (dev) {
+			u8 value1 = 0, value2 = 0;
+
+			pci_read_config_byte(dev, 0x76, &value1);
+			pci_read_config_byte(dev, 0x77, &value2);
 			if ((value1 & 0x80) || (value2 & 0x80)) {
 				errata.piix4.fdma = 1;
-				dev_dbg(&isa_dev->dev,
+				dev_dbg(&dev->dev,
 					"Type-F DMA livelock erratum (C3 disabled)\n");
 			}
-			pci_dev_put(isa_dev);
+			pci_dev_put(dev);
 		}
 
 		break;
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index f0e513e9ed5d..053fc6765a59 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -177,12 +177,12 @@ __ATTR(_name, 0444, show_##_name, NULL)
 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, highest_perf);
 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_perf);
 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_perf);
+show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, reference_perf);
 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_nonlinear_perf);
 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, guaranteed_perf);
 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_freq);
 show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_freq);
 
-show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, reference_perf);
 show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, wraparound_time);
 
 /* Check for valid access_width, otherwise, fallback to using bit_width */
@@ -854,6 +854,16 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
 	per_cpu(cpu_pcc_subspace_idx, pr->id) = pcc_subspace_id;
 
 	/*
+	 * In CPPC v1, DESIRED_PERF is mandatory. In CPPC v2, it is optional
+	 * only when AUTO_SEL_ENABLE is supported.
+	 */
+	if (!CPC_SUPPORTED(&cpc_ptr->cpc_regs[DESIRED_PERF]) &&
+	    (!osc_sb_cppc2_support_acked ||
+	     !CPC_SUPPORTED(&cpc_ptr->cpc_regs[AUTO_SEL_ENABLE])))
+		pr_warn("Desired perf. register is mandatory if CPPC v2 is not supported "
+			"or autonomous selection is disabled\n");
+
+	/*
 	 * Initialize the remaining cpc_regs as unsupported.
 	 * Example: In case FW exposes CPPC v2, the below loop will initialize
 	 * LOWEST_FREQ and NOMINAL_FREQ regs as unsupported
@@ -1342,9 +1352,10 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
 {
 	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
 	struct cpc_register_resource *highest_reg, *lowest_reg,
-		*lowest_non_linear_reg, *nominal_reg, *guaranteed_reg,
-		*low_freq_reg = NULL, *nom_freq_reg = NULL;
-	u64 high, low, guaranteed, nom, min_nonlinear, low_f = 0, nom_f = 0;
+		*lowest_non_linear_reg, *nominal_reg, *reference_reg,
+		*guaranteed_reg, *low_freq_reg = NULL, *nom_freq_reg = NULL;
+	u64 high, low, guaranteed, nom, ref, min_nonlinear,
+	    low_f = 0, nom_f = 0;
 	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
 	struct cppc_pcc_data *pcc_ss_data = NULL;
 	int ret = 0, regs_in_pcc = 0;
@@ -1358,6 +1369,7 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
 	lowest_reg = &cpc_desc->cpc_regs[LOWEST_PERF];
 	lowest_non_linear_reg = &cpc_desc->cpc_regs[LOW_NON_LINEAR_PERF];
 	nominal_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
+	reference_reg = &cpc_desc->cpc_regs[REFERENCE_PERF];
 	low_freq_reg = &cpc_desc->cpc_regs[LOWEST_FREQ];
 	nom_freq_reg = &cpc_desc->cpc_regs[NOMINAL_FREQ];
 	guaranteed_reg = &cpc_desc->cpc_regs[GUARANTEED_PERF];
@@ -1365,6 +1377,7 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
 	/* Are any of the regs PCC ?*/
 	if (CPC_IN_PCC(highest_reg) || CPC_IN_PCC(lowest_reg) ||
 		CPC_IN_PCC(lowest_non_linear_reg) || CPC_IN_PCC(nominal_reg) ||
+		(CPC_SUPPORTED(reference_reg) && CPC_IN_PCC(reference_reg)) ||
 		CPC_IN_PCC(low_freq_reg) || CPC_IN_PCC(nom_freq_reg) ||
 		CPC_IN_PCC(guaranteed_reg)) {
 		if (pcc_ss_id < 0) {
@@ -1381,35 +1394,66 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
 		}
 	}
 
-	cpc_read(cpunum, highest_reg, &high);
+	ret = cpc_read(cpunum, highest_reg, &high);
+	if (ret)
+		goto out_err;
 	perf_caps->highest_perf = high;
 
-	cpc_read(cpunum, lowest_reg, &low);
+	ret = cpc_read(cpunum, lowest_reg, &low);
+	if (ret)
+		goto out_err;
 	perf_caps->lowest_perf = low;
 
-	cpc_read(cpunum, nominal_reg, &nom);
+	ret = cpc_read(cpunum, nominal_reg, &nom);
+	if (ret)
+		goto out_err;
 	perf_caps->nominal_perf = nom;
 
+	/*
+	 * If reference perf register is not supported then we should
+	 * use the nominal perf value
+	 */
+	if (CPC_SUPPORTED(reference_reg)) {
+		ret = cpc_read(cpunum, reference_reg, &ref);
+		if (ret)
+			goto out_err;
+	} else {
+		ref = nom;
+	}
+	perf_caps->reference_perf = ref;
+
 	if (guaranteed_reg->type != ACPI_TYPE_BUFFER  ||
 	    IS_NULL_REG(&guaranteed_reg->cpc_entry.reg)) {
 		perf_caps->guaranteed_perf = 0;
 	} else {
-		cpc_read(cpunum, guaranteed_reg, &guaranteed);
+		ret = cpc_read(cpunum, guaranteed_reg, &guaranteed);
+		if (ret)
+			goto out_err;
 		perf_caps->guaranteed_perf = guaranteed;
 	}
 
-	cpc_read(cpunum, lowest_non_linear_reg, &min_nonlinear);
+	ret = cpc_read(cpunum, lowest_non_linear_reg, &min_nonlinear);
+	if (ret)
+		goto out_err;
 	perf_caps->lowest_nonlinear_perf = min_nonlinear;
 
-	if (!high || !low || !nom || !min_nonlinear)
+	if (!high || !low || !nom || !ref || !min_nonlinear) {
 		ret = -EFAULT;
+		goto out_err;
+	}
 
 	/* Read optional lowest and nominal frequencies if present */
-	if (CPC_SUPPORTED(low_freq_reg))
-		cpc_read(cpunum, low_freq_reg, &low_f);
+	if (CPC_SUPPORTED(low_freq_reg)) {
+		ret = cpc_read(cpunum, low_freq_reg, &low_f);
+		if (ret)
+			goto out_err;
+	}
 
-	if (CPC_SUPPORTED(nom_freq_reg))
-		cpc_read(cpunum, nom_freq_reg, &nom_f);
+	if (CPC_SUPPORTED(nom_freq_reg)) {
+		ret = cpc_read(cpunum, nom_freq_reg, &nom_f);
+		if (ret)
+			goto out_err;
+	}
 
 	perf_caps->lowest_freq = low_f;
 	perf_caps->nominal_freq = nom_f;
@@ -1431,20 +1475,10 @@ EXPORT_SYMBOL_GPL(cppc_get_perf_caps);
 bool cppc_perf_ctrs_in_pcc_cpu(unsigned int cpu)
 {
 	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
-	struct cpc_register_resource *ref_perf_reg;
-
-	/*
-	 * If reference perf register is not supported then we should use the
-	 * nominal perf value
-	 */
-	ref_perf_reg = &cpc_desc->cpc_regs[REFERENCE_PERF];
-	if (!CPC_SUPPORTED(ref_perf_reg))
-		ref_perf_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
 
 	return CPC_IN_PCC(&cpc_desc->cpc_regs[DELIVERED_CTR]) ||
 		CPC_IN_PCC(&cpc_desc->cpc_regs[REFERENCE_CTR]) ||
-		CPC_IN_PCC(&cpc_desc->cpc_regs[CTR_WRAP_TIME]) ||
-		CPC_IN_PCC(ref_perf_reg);
+		CPC_IN_PCC(&cpc_desc->cpc_regs[CTR_WRAP_TIME]);
 }
 EXPORT_SYMBOL_GPL(cppc_perf_ctrs_in_pcc_cpu);
 
@@ -1481,10 +1515,10 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
 {
 	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
 	struct cpc_register_resource *delivered_reg, *reference_reg,
-		*ref_perf_reg, *ctr_wrap_reg;
+		*ctr_wrap_reg;
 	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
 	struct cppc_pcc_data *pcc_ss_data = NULL;
-	u64 delivered, reference, ref_perf, ctr_wrap_time;
+	u64 delivered, reference, ctr_wrap_time;
 	int ret = 0, regs_in_pcc = 0;
 
 	if (!cpc_desc) {
@@ -1494,19 +1528,11 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
 
 	delivered_reg = &cpc_desc->cpc_regs[DELIVERED_CTR];
 	reference_reg = &cpc_desc->cpc_regs[REFERENCE_CTR];
-	ref_perf_reg = &cpc_desc->cpc_regs[REFERENCE_PERF];
 	ctr_wrap_reg = &cpc_desc->cpc_regs[CTR_WRAP_TIME];
 
-	/*
-	 * If reference perf register is not supported then we should
-	 * use the nominal perf value
-	 */
-	if (!CPC_SUPPORTED(ref_perf_reg))
-		ref_perf_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
-
 	/* Are any of the regs PCC ?*/
 	if (CPC_IN_PCC(delivered_reg) || CPC_IN_PCC(reference_reg) ||
-		CPC_IN_PCC(ctr_wrap_reg) || CPC_IN_PCC(ref_perf_reg)) {
+		CPC_IN_PCC(ctr_wrap_reg)) {
 		if (pcc_ss_id < 0) {
 			pr_debug("Invalid pcc_ss_id\n");
 			return -ENODEV;
@@ -1521,9 +1547,13 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
 		}
 	}
 
-	cpc_read(cpunum, delivered_reg, &delivered);
-	cpc_read(cpunum, reference_reg, &reference);
-	cpc_read(cpunum, ref_perf_reg, &ref_perf);
+	ret = cpc_read(cpunum, delivered_reg, &delivered);
+	if (ret)
+		goto out_err;
+
+	ret = cpc_read(cpunum, reference_reg, &reference);
+	if (ret)
+		goto out_err;
 
 	/*
 	 * Per spec, if ctr_wrap_time optional register is unsupported, then the
@@ -1531,17 +1561,19 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
 	 * platform
 	 */
 	ctr_wrap_time = (u64)(~((u64)0));
-	if (CPC_SUPPORTED(ctr_wrap_reg))
-		cpc_read(cpunum, ctr_wrap_reg, &ctr_wrap_time);
+	if (CPC_SUPPORTED(ctr_wrap_reg)) {
+		ret = cpc_read(cpunum, ctr_wrap_reg, &ctr_wrap_time);
+		if (ret)
+			goto out_err;
+	}
 
-	if (!delivered || !reference ||	!ref_perf) {
+	if (!delivered || !reference) {
 		ret = -EFAULT;
 		goto out_err;
 	}
 
 	perf_fb_ctrs->delivered = delivered;
 	perf_fb_ctrs->reference = reference;
-	perf_fb_ctrs->reference_perf = ref_perf;
 	perf_fb_ctrs->wraparound_time = ctr_wrap_time;
 out_err:
 	if (regs_in_pcc)
@@ -1561,6 +1593,8 @@ int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable)
 	struct cpc_register_resource *auto_sel_reg;
 	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
 	struct cppc_pcc_data *pcc_ss_data = NULL;
+	bool autosel_ffh_sysmem;
+	bool epp_ffh_sysmem;
 	int ret;
 
 	if (!cpc_desc) {
@@ -1571,6 +1605,11 @@ int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable)
 	auto_sel_reg = &cpc_desc->cpc_regs[AUTO_SEL_ENABLE];
 	epp_set_reg = &cpc_desc->cpc_regs[ENERGY_PERF];
 
+	epp_ffh_sysmem = CPC_SUPPORTED(epp_set_reg) &&
+		(CPC_IN_FFH(epp_set_reg) || CPC_IN_SYSTEM_MEMORY(epp_set_reg));
+	autosel_ffh_sysmem = CPC_SUPPORTED(auto_sel_reg) &&
+		(CPC_IN_FFH(auto_sel_reg) || CPC_IN_SYSTEM_MEMORY(auto_sel_reg));
+
 	if (CPC_IN_PCC(epp_set_reg) || CPC_IN_PCC(auto_sel_reg)) {
 		if (pcc_ss_id < 0) {
 			pr_debug("Invalid pcc_ss_id for CPU:%d\n", cpu);
@@ -1596,11 +1635,22 @@ int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable)
 		ret = send_pcc_cmd(pcc_ss_id, CMD_WRITE);
 		up_write(&pcc_ss_data->pcc_lock);
 	} else if (osc_cpc_flexible_adr_space_confirmed &&
-		   CPC_SUPPORTED(epp_set_reg) && CPC_IN_FFH(epp_set_reg)) {
-		ret = cpc_write(cpu, epp_set_reg, perf_ctrls->energy_perf);
+		   (epp_ffh_sysmem || autosel_ffh_sysmem)) {
+		if (autosel_ffh_sysmem) {
+			ret = cpc_write(cpu, auto_sel_reg, enable);
+			if (ret)
+				return ret;
+		}
+
+		if (epp_ffh_sysmem) {
+			ret = cpc_write(cpu, epp_set_reg,
+					perf_ctrls->energy_perf);
+			if (ret)
+				return ret;
+		}
 	} else {
 		ret = -ENOTSUPP;
-		pr_debug("_CPC in PCC and _CPC in FFH are not supported\n");
+		pr_debug("_CPC in PCC/FFH/SystemMemory are not supported\n");
 	}
 
 	return ret;
@@ -1739,6 +1789,101 @@ int cppc_set_enable(int cpu, bool enable)
 EXPORT_SYMBOL_GPL(cppc_set_enable);
 
 /**
+ * cppc_get_perf - Get a CPU's performance controls.
+ * @cpu: CPU for which to get performance controls.
+ * @perf_ctrls: ptr to cppc_perf_ctrls. See cppc_acpi.h
+ *
+ * Return: 0 for success with perf_ctrls, -ERRNO otherwise.
+ */
+int cppc_get_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
+{
+	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
+	struct cpc_register_resource *desired_perf_reg,
+				     *min_perf_reg, *max_perf_reg,
+				     *energy_perf_reg, *auto_sel_reg;
+	u64 desired_perf = 0, min = 0, max = 0, energy_perf = 0, auto_sel = 0;
+	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
+	struct cppc_pcc_data *pcc_ss_data = NULL;
+	int ret = 0, regs_in_pcc = 0;
+
+	if (!cpc_desc) {
+		pr_debug("No CPC descriptor for CPU:%d\n", cpu);
+		return -ENODEV;
+	}
+
+	if (!perf_ctrls) {
+		pr_debug("Invalid perf_ctrls pointer\n");
+		return -EINVAL;
+	}
+
+	desired_perf_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
+	min_perf_reg = &cpc_desc->cpc_regs[MIN_PERF];
+	max_perf_reg = &cpc_desc->cpc_regs[MAX_PERF];
+	energy_perf_reg = &cpc_desc->cpc_regs[ENERGY_PERF];
+	auto_sel_reg = &cpc_desc->cpc_regs[AUTO_SEL_ENABLE];
+
+	/* Are any of the regs PCC ?*/
+	if (CPC_IN_PCC(desired_perf_reg) || CPC_IN_PCC(min_perf_reg) ||
+	    CPC_IN_PCC(max_perf_reg) || CPC_IN_PCC(energy_perf_reg) ||
+	    CPC_IN_PCC(auto_sel_reg)) {
+		if (pcc_ss_id < 0) {
+			pr_debug("Invalid pcc_ss_id for CPU:%d\n", cpu);
+			return -ENODEV;
+		}
+		pcc_ss_data = pcc_data[pcc_ss_id];
+		regs_in_pcc = 1;
+		down_write(&pcc_ss_data->pcc_lock);
+		/* Ring doorbell once to update PCC subspace */
+		if (send_pcc_cmd(pcc_ss_id, CMD_READ) < 0) {
+			ret = -EIO;
+			goto out_err;
+		}
+	}
+
+	/* Read optional elements if present */
+	if (CPC_SUPPORTED(max_perf_reg)) {
+		ret = cpc_read(cpu, max_perf_reg, &max);
+		if (ret)
+			goto out_err;
+	}
+	perf_ctrls->max_perf = max;
+
+	if (CPC_SUPPORTED(min_perf_reg)) {
+		ret = cpc_read(cpu, min_perf_reg, &min);
+		if (ret)
+			goto out_err;
+	}
+	perf_ctrls->min_perf = min;
+
+	if (CPC_SUPPORTED(desired_perf_reg)) {
+		ret = cpc_read(cpu, desired_perf_reg, &desired_perf);
+		if (ret)
+			goto out_err;
+	}
+	perf_ctrls->desired_perf = desired_perf;
+
+	if (CPC_SUPPORTED(energy_perf_reg)) {
+		ret = cpc_read(cpu, energy_perf_reg, &energy_perf);
+		if (ret)
+			goto out_err;
+	}
+	perf_ctrls->energy_perf = energy_perf;
+
+	if (CPC_SUPPORTED(auto_sel_reg)) {
+		ret = cpc_read(cpu, auto_sel_reg, &auto_sel);
+		if (ret)
+			goto out_err;
+	}
+	perf_ctrls->auto_sel = (bool)auto_sel;
+
+out_err:
+	if (regs_in_pcc)
+		up_write(&pcc_ss_data->pcc_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(cppc_get_perf);
+
+/**
  * cppc_set_perf - Set a CPU's performance controls.
  * @cpu: CPU for which to set performance controls.
  * @perf_ctrls: ptr to cppc_perf_ctrls. See cppc_acpi.h
@@ -1871,6 +2016,62 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
 EXPORT_SYMBOL_GPL(cppc_set_perf);
 
 /**
+ * cppc_get_perf_limited - Get the Performance Limited register value.
+ * @cpu: CPU from which to get Performance Limited register.
+ * @perf_limited: Pointer to store the Performance Limited value.
+ *
+ * The returned value contains sticky status bits indicating platform-imposed
+ * performance limitations.
+ *
+ * Return: 0 for success, -EIO on failure, -EOPNOTSUPP if not supported.
+ */
+int cppc_get_perf_limited(int cpu, u64 *perf_limited)
+{
+	return cppc_get_reg_val(cpu, PERF_LIMITED, perf_limited);
+}
+EXPORT_SYMBOL_GPL(cppc_get_perf_limited);
+
+/**
+ * cppc_set_perf_limited() - Clear bits in the Performance Limited register.
+ * @cpu: CPU on which to write register.
+ * @bits_to_clear: Bitmask of bits to clear in the perf_limited register.
+ *
+ * The Performance Limited register contains two sticky bits set by platform:
+ *   - Bit 0 (Desired_Excursion): Set when delivered performance is constrained
+ *     below desired performance. Not used when Autonomous Selection is enabled.
+ *   - Bit 1 (Minimum_Excursion): Set when delivered performance is constrained
+ *     below minimum performance.
+ *
+ * These bits are sticky and remain set until OSPM explicitly clears them.
+ * This function only allows clearing bits (the platform sets them).
+ *
+ * Return: 0 for success, -EINVAL for invalid bits, -EIO on register
+ *         access failure, -EOPNOTSUPP if not supported.
+ */
+int cppc_set_perf_limited(int cpu, u64 bits_to_clear)
+{
+	u64 current_val, new_val;
+	int ret;
+
+	/* Only bits 0 and 1 are valid */
+	if (bits_to_clear & ~CPPC_PERF_LIMITED_MASK)
+		return -EINVAL;
+
+	if (!bits_to_clear)
+		return 0;
+
+	ret = cppc_get_perf_limited(cpu, &current_val);
+	if (ret)
+		return ret;
+
+	/* Clear the specified bits */
+	new_val = current_val & ~bits_to_clear;
+
+	return cppc_set_reg_val(cpu, PERF_LIMITED, new_val);
+}
+EXPORT_SYMBOL_GPL(cppc_set_perf_limited);
+
+/**
  * cppc_get_transition_latency - returns frequency transition latency in ns
  * @cpu_num: CPU number for per_cpu().
  *
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index f6c72e3a2be1..ee5facccbe10 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -819,19 +819,13 @@ static void acpi_processor_setup_cstates(struct acpi_processor *pr)
 	drv->state_count = count;
 }
 
-static inline void acpi_processor_cstate_first_run_checks(void)
+static inline void acpi_processor_update_max_cstate(void)
 {
-	static int first_run;
-
-	if (first_run)
-		return;
 	dmi_check_system(processor_power_dmi_table);
 	max_cstate = acpi_processor_cstate_check(max_cstate);
 	if (max_cstate < ACPI_C_STATES_MAX)
 		pr_notice("processor limited to max C-state %d\n", max_cstate);
 
-	first_run++;
-
 	if (nocst)
 		return;
 
@@ -840,7 +834,7 @@ static inline void acpi_processor_cstate_first_run_checks(void)
 #else
 
 static inline int disabled_by_idle_boot_param(void) { return 0; }
-static inline void acpi_processor_cstate_first_run_checks(void) { }
+static inline void acpi_processor_update_max_cstate(void) { }
 static int acpi_processor_get_cstate_info(struct acpi_processor *pr)
 {
 	return -ENODEV;
@@ -1016,9 +1010,7 @@ static bool combine_lpi_states(struct acpi_lpi_state *local,
 	result->arch_flags = parent->arch_flags;
 	result->index = parent->index;
 
-	strscpy(result->desc, local->desc, ACPI_CX_DESC_LEN);
-	strlcat(result->desc, "+", ACPI_CX_DESC_LEN);
-	strlcat(result->desc, parent->desc, ACPI_CX_DESC_LEN);
+	scnprintf(result->desc, ACPI_CX_DESC_LEN, "%s+%s", local->desc, parent->desc);
 	return true;
 }
 
@@ -1068,6 +1060,8 @@ static unsigned int flatten_lpi_states(struct acpi_processor *pr,
 				stash_composite_state(curr_level, flpi);
 				flat_state_cnt++;
 				flpi++;
+				if (flat_state_cnt >= ACPI_PROCESSOR_MAX_POWER)
+					break;
 			}
 		}
 	}
@@ -1273,16 +1267,15 @@ static int acpi_processor_get_power_info(struct acpi_processor *pr)
 
 int acpi_processor_hotplug(struct acpi_processor *pr)
 {
+	struct cpuidle_device *dev = per_cpu(acpi_cpuidle_device, pr->id);
 	int ret = 0;
-	struct cpuidle_device *dev;
 
 	if (disabled_by_idle_boot_param())
 		return 0;
 
-	if (!pr->flags.power_setup_done)
+	if (!pr->flags.power_setup_done || !dev)
 		return -ENODEV;
 
-	dev = per_cpu(acpi_cpuidle_device, pr->id);
 	cpuidle_pause_and_lock();
 	cpuidle_disable_device(dev);
 	ret = acpi_processor_get_power_info(pr);
@@ -1314,37 +1307,42 @@ int acpi_processor_power_state_has_changed(struct acpi_processor *pr)
 	 */
 
 	if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) {
-
 		/* Protect against cpu-hotplug */
 		cpus_read_lock();
-		cpuidle_pause_and_lock();
 
-		/* Disable all cpuidle devices */
-		for_each_online_cpu(cpu) {
+		/* Unregister cpuidle device of all CPUs */
+		cpuidle_pause_and_lock();
+		for_each_possible_cpu(cpu) {
+			dev = per_cpu(acpi_cpuidle_device, cpu);
 			_pr = per_cpu(processors, cpu);
-			if (!_pr || !_pr->flags.power_setup_done)
+			if (!_pr || !_pr->flags.power || !dev)
 				continue;
-			dev = per_cpu(acpi_cpuidle_device, cpu);
-			cpuidle_disable_device(dev);
+
+			cpuidle_unregister_device_no_lock(dev);
+			kfree(dev);
+			_pr->flags.power = 0;
 		}
+		cpuidle_resume_and_unlock();
 
-		/* Populate Updated C-state information */
-		acpi_processor_get_power_info(pr);
-		acpi_processor_setup_cpuidle_states(pr);
+		/*
+		 * Unregister ACPI idle driver, reinitialize ACPI idle states
+		 * and register ACPI idle driver again.
+		 */
+		acpi_processor_unregister_idle_driver();
+		acpi_processor_register_idle_driver();
 
-		/* Enable all cpuidle devices */
-		for_each_online_cpu(cpu) {
+		/*
+		 * Reinitialize power information of all CPUs and re-register
+		 * all cpuidle devices. Now idle states is ok to use, can enable
+		 * cpuidle of each CPU safely one by one.
+		 */
+		for_each_possible_cpu(cpu) {
 			_pr = per_cpu(processors, cpu);
-			if (!_pr || !_pr->flags.power_setup_done)
+			if (!_pr)
 				continue;
-			acpi_processor_get_power_info(_pr);
-			if (_pr->flags.power) {
-				dev = per_cpu(acpi_cpuidle_device, cpu);
-				acpi_processor_setup_cpuidle_dev(_pr, dev);
-				cpuidle_enable_device(dev);
-			}
+			acpi_processor_power_init(_pr);
 		}
-		cpuidle_resume_and_unlock();
+
 		cpus_read_unlock();
 	}
 
@@ -1357,6 +1355,8 @@ void acpi_processor_register_idle_driver(void)
 	int ret = -ENODEV;
 	int cpu;
 
+	acpi_processor_update_max_cstate();
+
 	/*
 	 * ACPI idle driver is used by all possible CPUs.
 	 * Use the processor power info of one in them to set up idle states.
@@ -1368,7 +1368,6 @@ void acpi_processor_register_idle_driver(void)
 		if (!pr)
 			continue;
 
-		acpi_processor_cstate_first_run_checks();
 		ret = acpi_processor_get_power_info(pr);
 		if (!ret) {
 			pr->flags.power_setup_done = 1;
@@ -1384,6 +1383,7 @@ void acpi_processor_register_idle_driver(void)
 
 	ret = cpuidle_register_driver(&acpi_idle_driver);
 	if (ret) {
+		pr->flags.power_setup_done = 0;
 		pr_debug("register %s failed.\n", acpi_idle_driver.name);
 		return;
 	}
@@ -1392,7 +1392,16 @@ void acpi_processor_register_idle_driver(void)
 
 void acpi_processor_unregister_idle_driver(void)
 {
+	struct acpi_processor *pr;
+	int cpu;
+
 	cpuidle_unregister_driver(&acpi_idle_driver);
+	for_each_possible_cpu(cpu) {
+		pr = per_cpu(processors, cpu);
+		if (!pr)
+			continue;
+		pr->flags.power_setup_done = 0;
+	}
 }
 
 void acpi_processor_power_init(struct acpi_processor *pr)
@@ -1409,8 +1418,6 @@ void acpi_processor_power_init(struct acpi_processor *pr)
 	if (disabled_by_idle_boot_param())
 		return;
 
-	acpi_processor_cstate_first_run_checks();
-
 	if (!acpi_processor_get_power_info(pr))
 		pr->flags.power_setup_done = 1;
 
@@ -1431,6 +1438,7 @@ void acpi_processor_power_init(struct acpi_processor *pr)
 	 */
 	if (cpuidle_register_device(dev)) {
 		per_cpu(acpi_cpuidle_device, pr->id) = NULL;
+		pr->flags.power_setup_done = 0;
 		kfree(dev);
 	}
 }