1 files changed, 105 insertions, 54 deletions

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 735c74a4cbdb..d9ce4b162e2c 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -39,6 +39,7 @@
 
 #include <linux/cpufreq.h>
 #include <linux/delay.h>
+#include <linux/iopoll.h>
 #include <linux/ktime.h>
 #include <linux/rwsem.h>
 #include <linux/wait.h>
@@ -49,7 +50,7 @@ struct cppc_pcc_data {
 	struct mbox_chan *pcc_channel;
 	void __iomem *pcc_comm_addr;
 	bool pcc_channel_acquired;
-	ktime_t deadline;
+	unsigned int deadline_us;
 	unsigned int pcc_mpar, pcc_mrtt, pcc_nominal;
 
 	bool pending_pcc_write_cmd;	/* Any pending/batched PCC write cmds? */
@@ -156,6 +157,9 @@ 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, lowest_nonlinear_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);
 
@@ -183,6 +187,8 @@ static struct attribute *cppc_attrs[] = {
 	&lowest_perf.attr,
 	&lowest_nonlinear_perf.attr,
 	&nominal_perf.attr,
+	&nominal_freq.attr,
+	&lowest_freq.attr,
 	NULL
 };
 
@@ -193,42 +199,31 @@ static struct kobj_type cppc_ktype = {
 
 static int check_pcc_chan(int pcc_ss_id, bool chk_err_bit)
 {
-	int ret = -EIO, status = 0;
+	int ret, status;
 	struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
 	struct acpi_pcct_shared_memory __iomem *generic_comm_base =
 		pcc_ss_data->pcc_comm_addr;
-	ktime_t next_deadline = ktime_add(ktime_get(),
-					  pcc_ss_data->deadline);
 
 	if (!pcc_ss_data->platform_owns_pcc)
 		return 0;
 
-	/* Retry in case the remote processor was too slow to catch up. */
-	while (!ktime_after(ktime_get(), next_deadline)) {
-		/*
-		 * Per spec, prior to boot the PCC space wil be initialized by
-		 * platform and should have set the command completion bit when
-		 * PCC can be used by OSPM
-		 */
-		status = readw_relaxed(&generic_comm_base->status);
-		if (status & PCC_CMD_COMPLETE_MASK) {
-			ret = 0;
-			if (chk_err_bit && (status & PCC_ERROR_MASK))
-				ret = -EIO;
-			break;
-		}
-		/*
-		 * Reducing the bus traffic in case this loop takes longer than
-		 * a few retries.
-		 */
-		udelay(3);
-	}
+	/*
+	 * Poll PCC status register every 3us(delay_us) for maximum of
+	 * deadline_us(timeout_us) until PCC command complete bit is set(cond)
+	 */
+	ret = readw_relaxed_poll_timeout(&generic_comm_base->status, status,
+					status & PCC_CMD_COMPLETE_MASK, 3,
+					pcc_ss_data->deadline_us);
 
-	if (likely(!ret))
+	if (likely(!ret)) {
 		pcc_ss_data->platform_owns_pcc = false;
-	else
-		pr_err("PCC check channel failed for ss: %d. Status=%x\n",
-		       pcc_ss_id, status);
+		if (chk_err_bit && (status & PCC_ERROR_MASK))
+			ret = -EIO;
+	}
+
+	if (unlikely(ret))
+		pr_err("PCC check channel failed for ss: %d. ret=%d\n",
+		       pcc_ss_id, ret);
 
 	return ret;
 }
@@ -580,7 +575,7 @@ static int register_pcc_channel(int pcc_ss_idx)
 		 * So add an arbitrary amount of wait on top of Nominal.
 		 */
 		usecs_lat = NUM_RETRIES * cppc_ss->latency;
-		pcc_data[pcc_ss_idx]->deadline = ns_to_ktime(usecs_lat * NSEC_PER_USEC);
+		pcc_data[pcc_ss_idx]->deadline_us = usecs_lat;
 		pcc_data[pcc_ss_idx]->pcc_mrtt = cppc_ss->min_turnaround_time;
 		pcc_data[pcc_ss_idx]->pcc_mpar = cppc_ss->max_access_rate;
 		pcc_data[pcc_ss_idx]->pcc_nominal = cppc_ss->latency;
@@ -613,7 +608,6 @@ bool __weak cpc_ffh_supported(void)
 	return false;
 }
 
-
 /**
  * pcc_data_alloc() - Allocate the pcc_data memory for pcc subspace
  *
@@ -641,6 +635,34 @@ int pcc_data_alloc(int pcc_ss_id)
 
 	return 0;
 }
+
+/* Check if CPPC revision + num_ent combination is supported */
+static bool is_cppc_supported(int revision, int num_ent)
+{
+	int expected_num_ent;
+
+	switch (revision) {
+	case CPPC_V2_REV:
+		expected_num_ent = CPPC_V2_NUM_ENT;
+		break;
+	case CPPC_V3_REV:
+		expected_num_ent = CPPC_V3_NUM_ENT;
+		break;
+	default:
+		pr_debug("Firmware exports unsupported CPPC revision: %d\n",
+			revision);
+		return false;
+	}
+
+	if (expected_num_ent != num_ent) {
+		pr_debug("Firmware exports %d entries. Expected: %d for CPPC rev:%d\n",
+			num_ent, expected_num_ent, revision);
+		return false;
+	}
+
+	return true;
+}
+
 /*
  * An example CPC table looks like the following.
  *
@@ -731,14 +753,6 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
 				cpc_obj->type);
 		goto out_free;
 	}
-
-	/* Only support CPPCv2. Bail otherwise. */
-	if (num_ent != CPPC_NUM_ENT) {
-		pr_debug("Firmware exports %d entries. Expected: %d\n",
-				num_ent, CPPC_NUM_ENT);
-		goto out_free;
-	}
-
 	cpc_ptr->num_entries = num_ent;
 
 	/* Second entry should be revision. */
@@ -750,12 +764,10 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
 				cpc_obj->type);
 		goto out_free;
 	}
+	cpc_ptr->version = cpc_rev;
 
-	if (cpc_rev != CPPC_REV) {
-		pr_debug("Firmware exports revision:%d. Expected:%d\n",
-				cpc_rev, CPPC_REV);
+	if (!is_cppc_supported(cpc_rev, num_ent))
 		goto out_free;
-	}
 
 	/* Iterate through remaining entries in _CPC */
 	for (i = 2; i < num_ent; i++) {
@@ -808,6 +820,18 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
 		}
 	}
 	per_cpu(cpu_pcc_subspace_idx, pr->id) = pcc_subspace_id;
+
+	/*
+	 * 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
+	 */
+	for (i = num_ent - 2; i < MAX_CPC_REG_ENT; i++) {
+		cpc_ptr->cpc_regs[i].type = ACPI_TYPE_INTEGER;
+		cpc_ptr->cpc_regs[i].cpc_entry.int_value = 0;
+	}
+
+
 	/* Store CPU Logical ID */
 	cpc_ptr->cpu_id = pr->id;
 
@@ -1037,26 +1061,34 @@ 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;
-	u64 high, low, nom, min_nonlinear;
+		*lowest_non_linear_reg, *nominal_reg,
+		*low_freq_reg = NULL, *nom_freq_reg = NULL;
+	u64 high, low, nom, 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;
+	struct cppc_pcc_data *pcc_ss_data = NULL;
 	int ret = 0, regs_in_pcc = 0;
 
-	if (!cpc_desc || pcc_ss_id < 0) {
+	if (!cpc_desc) {
 		pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
 		return -ENODEV;
 	}
 
-	pcc_ss_data = pcc_data[pcc_ss_id];
 	highest_reg = &cpc_desc->cpc_regs[HIGHEST_PERF];
 	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];
+	low_freq_reg = &cpc_desc->cpc_regs[LOWEST_FREQ];
+	nom_freq_reg = &cpc_desc->cpc_regs[NOMINAL_FREQ];
 
 	/* 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_IN_PCC(lowest_non_linear_reg) || CPC_IN_PCC(nominal_reg) ||
+		CPC_IN_PCC(low_freq_reg) || CPC_IN_PCC(nom_freq_reg)) {
+		if (pcc_ss_id < 0) {
+			pr_debug("Invalid pcc_ss_id\n");
+			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 */
@@ -1081,6 +1113,17 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
 	if (!high || !low || !nom || !min_nonlinear)
 		ret = -EFAULT;
 
+	/* 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(nom_freq_reg))
+		cpc_read(cpunum, nom_freq_reg, &nom_f);
+
+	perf_caps->lowest_freq = low_f;
+	perf_caps->nominal_freq = nom_f;
+
+
 out_err:
 	if (regs_in_pcc)
 		up_write(&pcc_ss_data->pcc_lock);
@@ -1101,16 +1144,15 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
 	struct cpc_register_resource *delivered_reg, *reference_reg,
 		*ref_perf_reg, *ctr_wrap_reg;
 	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
-	struct cppc_pcc_data *pcc_ss_data;
+	struct cppc_pcc_data *pcc_ss_data = NULL;
 	u64 delivered, reference, ref_perf, ctr_wrap_time;
 	int ret = 0, regs_in_pcc = 0;
 
-	if (!cpc_desc || pcc_ss_id < 0) {
+	if (!cpc_desc) {
 		pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
 		return -ENODEV;
 	}
 
-	pcc_ss_data = pcc_data[pcc_ss_id];
 	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];
@@ -1126,6 +1168,11 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
 	/* 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)) {
+		if (pcc_ss_id < 0) {
+			pr_debug("Invalid pcc_ss_id\n");
+			return -ENODEV;
+		}
+		pcc_ss_data = pcc_data[pcc_ss_id];
 		down_write(&pcc_ss_data->pcc_lock);
 		regs_in_pcc = 1;
 		/* Ring doorbell once to update PCC subspace */
@@ -1176,15 +1223,14 @@ int cppc_set_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_reg;
 	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
-	struct cppc_pcc_data *pcc_ss_data;
+	struct cppc_pcc_data *pcc_ss_data = NULL;
 	int ret = 0;
 
-	if (!cpc_desc || pcc_ss_id < 0) {
+	if (!cpc_desc) {
 		pr_debug("No CPC descriptor for CPU:%d\n", cpu);
 		return -ENODEV;
 	}
 
-	pcc_ss_data = pcc_data[pcc_ss_id];
 	desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
 
 	/*
@@ -1195,6 +1241,11 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
 	 * achieve that goal here
 	 */
 	if (CPC_IN_PCC(desired_reg)) {
+		if (pcc_ss_id < 0) {
+			pr_debug("Invalid pcc_ss_id\n");
+			return -ENODEV;
+		}
+		pcc_ss_data = pcc_data[pcc_ss_id];
 		down_read(&pcc_ss_data->pcc_lock); /* BEGIN Phase-I */
 		if (pcc_ss_data->platform_owns_pcc) {
 			ret = check_pcc_chan(pcc_ss_id, false);