[PATCH 2/2] ACPI / CPPC: Make cppc acpi driver aware of pcc subspace ids

[George Cherian <george.cherian@cavium.com>]

Based on Section 14.1 of ACPI specification, it is possible to have a
maximum of 256 PCC subspace ids. Add support of multiple PCC subspace id
instead of using a single global pcc_data structure.

While at that fix the time_delta check in send_pcc_cmd() so that last_mpar_reset
and mpar_count is initialized properly. Also maintain a global total_mpar_count
which is a sum of per subspace id mpar value.

Signed-off-by: George Cherian <george.cherian@cavium.com>
---
 drivers/acpi/cppc_acpi.c | 189 ++++++++++++++++++++++++++---------------------
 1 file changed, 105 insertions(+), 84 deletions(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 3ca0729..7ba05ac 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -77,12 +77,16 @@ struct cppc_pcc_data {
 	wait_queue_head_t pcc_write_wait_q;
 };
 
-/* Structure to represent the single PCC channel */
-static struct cppc_pcc_data pcc_data = {
-	.pcc_subspace_idx = -1,
-	.platform_owns_pcc = true,
-};
+/* Array  to represent the PCC channel per subspace id */
+static struct cppc_pcc_data pcc_data[MAX_PCC_SUBSPACES];
+/*
+ * It is quiet possible that multiple CPU's can share
+ * same subspace ids. The cpu_pcc_subspace_idx maintains
+ * the cpu to pcc subspace id map.
+ */
+static DEFINE_PER_CPU(int, cpu_pcc_subspace_idx);
 
+static int total_mpar_count;
 /*
  * The cpc_desc structure contains the ACPI register details
  * as described in the per CPU _CPC tables. The details
@@ -93,7 +97,8 @@ static struct cppc_pcc_data pcc_data = {
 static DEFINE_PER_CPU(struct cpc_desc *, cpc_desc_ptr);
 
 /* pcc mapped address + header size + offset within PCC subspace */
-#define GET_PCC_VADDR(offs) (pcc_data.pcc_comm_addr + 0x8 + (offs))
+#define GET_PCC_VADDR(offs, pcc_ss_id) (pcc_data[pcc_ss_id].pcc_comm_addr + \
+						0x8 + (offs))
 
 /* Check if a CPC regsiter is in PCC */
 #define CPC_IN_PCC(cpc) ((cpc)->type == ACPI_TYPE_BUFFER &&		\
@@ -183,13 +188,17 @@ static struct kobj_type cppc_ktype = {
 	.default_attrs = cppc_attrs,
 };
 
-static int check_pcc_chan(bool chk_err_bit)
+static int check_pcc_chan(int cpunum, bool chk_err_bit)
 {
 	int ret = -EIO, status = 0;
-	struct acpi_pcct_shared_memory __iomem *generic_comm_base = pcc_data.pcc_comm_addr;
-	ktime_t next_deadline = ktime_add(ktime_get(), pcc_data.deadline);
-
-	if (!pcc_data.platform_owns_pcc)
+	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
+	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. */
@@ -214,7 +223,7 @@ static int check_pcc_chan(bool chk_err_bit)
 	}
 
 	if (likely(!ret))
-		pcc_data.platform_owns_pcc = false;
+		pcc_ss_data->platform_owns_pcc = false;
 	else
 		pr_err("PCC check channel failed. Status=%x\n", status);
 
@@ -225,11 +234,13 @@ static int check_pcc_chan(bool chk_err_bit)
  * This function transfers the ownership of the PCC to the platform
  * So it must be called while holding write_lock(pcc_lock)
  */
-static int send_pcc_cmd(u16 cmd)
+static int send_pcc_cmd(int cpunum, u16 cmd)
 {
 	int ret = -EIO, i;
+	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
+	struct cppc_pcc_data *pcc_ss_data = &pcc_data[pcc_ss_id];
 	struct acpi_pcct_shared_memory *generic_comm_base =
-		(struct acpi_pcct_shared_memory *) pcc_data.pcc_comm_addr;
+		(struct acpi_pcct_shared_memory *)pcc_ss_data->pcc_comm_addr;
 	static ktime_t last_cmd_cmpl_time, last_mpar_reset;
 	static int mpar_count;
 	unsigned int time_delta;
@@ -244,24 +255,24 @@ static int send_pcc_cmd(u16 cmd)
 		 * before write completion, so first send a WRITE command to
 		 * platform
 		 */
-		if (pcc_data.pending_pcc_write_cmd)
-			send_pcc_cmd(CMD_WRITE);
+		if (pcc_ss_data->pending_pcc_write_cmd)
+			send_pcc_cmd(cpunum, CMD_WRITE);
 
-		ret = check_pcc_chan(false);
+		ret = check_pcc_chan(cpunum, false);
 		if (ret)
 			goto end;
 	} else /* CMD_WRITE */
-		pcc_data.pending_pcc_write_cmd = FALSE;
+		pcc_ss_data->pending_pcc_write_cmd = FALSE;
 
 	/*
 	 * Handle the Minimum Request Turnaround Time(MRTT)
 	 * "The minimum amount of time that OSPM must wait after the completion
 	 * of a command before issuing the next command, in microseconds"
 	 */
-	if (pcc_data.pcc_mrtt) {
+	if (pcc_ss_data->pcc_mrtt) {
 		time_delta = ktime_us_delta(ktime_get(), last_cmd_cmpl_time);
-		if (pcc_data.pcc_mrtt > time_delta)
-			udelay(pcc_data.pcc_mrtt - time_delta);
+		if (pcc_ss_data->pcc_mrtt > time_delta)
+			udelay(pcc_ss_data->pcc_mrtt - time_delta);
 	}
 
 	/*
@@ -275,16 +286,16 @@ static int send_pcc_cmd(u16 cmd)
 	 * not send the request to the platform after hitting the MPAR limit in
 	 * any 60s window
 	 */
-	if (pcc_data.pcc_mpar) {
+	if (pcc_ss_data->pcc_mpar) {
 		if (mpar_count == 0) {
 			time_delta = ktime_ms_delta(ktime_get(), last_mpar_reset);
-			if (time_delta < 60 * MSEC_PER_SEC) {
+			if ((time_delta < 60 * MSEC_PER_SEC) && last_mpar_reset) {
 				pr_debug("PCC cmd not sent due to MPAR limit");
 				ret = -EIO;
 				goto end;
 			}
 			last_mpar_reset = ktime_get();
-			mpar_count = pcc_data.pcc_mpar;
+			mpar_count = total_mpar_count;
 		}
 		mpar_count--;
 	}
@@ -295,10 +306,10 @@ static int send_pcc_cmd(u16 cmd)
 	/* Flip CMD COMPLETE bit */
 	writew_relaxed(0, &generic_comm_base->status);
 
-	pcc_data.platform_owns_pcc = true;
+	pcc_ss_data->platform_owns_pcc = true;
 
 	/* Ring doorbell */
-	ret = mbox_send_message(pcc_data.pcc_channel, &cmd);
+	ret = mbox_send_message(pcc_ss_data->pcc_channel, &cmd);
 	if (ret < 0) {
 		pr_err("Err sending PCC mbox message. cmd:%d, ret:%d\n",
 				cmd, ret);
@@ -306,15 +317,15 @@ static int send_pcc_cmd(u16 cmd)
 	}
 
 	/* wait for completion and check for PCC errro bit */
-	ret = check_pcc_chan(true);
+	ret = check_pcc_chan(cpunum, true);
 
-	if (pcc_data.pcc_mrtt)
+	if (pcc_ss_data->pcc_mrtt)
 		last_cmd_cmpl_time = ktime_get();
 
-	if (pcc_data.pcc_channel->mbox->txdone_irq)
-		mbox_chan_txdone(pcc_data.pcc_channel, ret);
+	if (pcc_ss_data->pcc_channel->mbox->txdone_irq)
+		mbox_chan_txdone(pcc_ss_data->pcc_channel, ret);
 	else
-		mbox_client_txdone(pcc_data.pcc_channel, ret);
+		mbox_client_txdone(pcc_ss_data->pcc_channel, ret);
 
 end:
 	if (cmd == CMD_WRITE) {
@@ -324,12 +335,12 @@ static int send_pcc_cmd(u16 cmd)
 				if (!desc)
 					continue;
 
-				if (desc->write_cmd_id == pcc_data.pcc_write_cnt)
+				if (desc->write_cmd_id == pcc_ss_data->pcc_write_cnt)
 					desc->write_cmd_status = ret;
 			}
 		}
-		pcc_data.pcc_write_cnt++;
-		wake_up_all(&pcc_data.pcc_write_wait_q);
+		pcc_ss_data->pcc_write_cnt++;
+		wake_up_all(&pcc_ss_data->pcc_write_wait_q);
 	}
 
 	return ret;
@@ -531,16 +542,16 @@ int acpi_get_psd_map(struct cppc_cpudata **all_cpu_data)
 }
 EXPORT_SYMBOL_GPL(acpi_get_psd_map);
 
-static int register_pcc_channel(int pcc_subspace_idx)
+static int register_pcc_channel(int pcc_ss_idx)
 {
 	struct acpi_pcct_hw_reduced *cppc_ss;
 	u64 usecs_lat;
 
-	if (pcc_subspace_idx >= 0) {
-		pcc_data.pcc_channel = pcc_mbox_request_channel(&cppc_mbox_cl,
-				pcc_subspace_idx);
+	if (pcc_ss_idx >= 0) {
+		pcc_data[pcc_ss_idx].pcc_channel =
+			pcc_mbox_request_channel(&cppc_mbox_cl,	pcc_ss_idx);
 
-		if (IS_ERR(pcc_data.pcc_channel)) {
+		if (IS_ERR(pcc_data[pcc_ss_idx].pcc_channel)) {
 			pr_err("Failed to find PCC communication channel\n");
 			return -ENODEV;
 		}
@@ -551,7 +562,7 @@ static int register_pcc_channel(int pcc_subspace_idx)
 		 * PCC channels) and stored pointers to the
 		 * subspace communication region in con_priv.
 		 */
-		cppc_ss = (pcc_data.pcc_channel)->con_priv;
+		cppc_ss = (pcc_data[pcc_ss_idx].pcc_channel)->con_priv;
 
 		if (!cppc_ss) {
 			pr_err("No PCC subspace found for CPPC\n");
@@ -564,19 +575,21 @@ static int register_pcc_channel(int pcc_subspace_idx)
 		 * So add an arbitrary amount of wait on top of Nominal.
 		 */
 		usecs_lat = NUM_RETRIES * cppc_ss->latency;
-		pcc_data.deadline = ns_to_ktime(usecs_lat * NSEC_PER_USEC);
-		pcc_data.pcc_mrtt = cppc_ss->min_turnaround_time;
-		pcc_data.pcc_mpar = cppc_ss->max_access_rate;
-		pcc_data.pcc_nominal = cppc_ss->latency;
-
-		pcc_data.pcc_comm_addr = acpi_os_ioremap(cppc_ss->base_address, cppc_ss->length);
-		if (!pcc_data.pcc_comm_addr) {
+		pcc_data[pcc_ss_idx].deadline = ns_to_ktime(usecs_lat * NSEC_PER_USEC);
+		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;
+		total_mpar_count += cppc_ss->max_access_rate;
+
+		pcc_data[pcc_ss_idx].pcc_comm_addr =
+			acpi_os_ioremap(cppc_ss->base_address, cppc_ss->length);
+		if (!pcc_data[pcc_ss_idx].pcc_comm_addr) {
 			pr_err("Failed to ioremap PCC comm region mem\n");
 			return -ENOMEM;
 		}
 
 		/* Set flag so that we dont come here for each CPU. */
-		pcc_data.pcc_channel_acquired = true;
+		pcc_data[pcc_ss_idx].pcc_channel_acquired = true;
 	}
 
 	return 0;
@@ -656,6 +669,7 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
 	struct device *cpu_dev;
 	acpi_handle handle = pr->handle;
 	unsigned int num_ent, i, cpc_rev;
+	unsigned int pcc_subspace_id = 0;
 	acpi_status status;
 	int ret = -EFAULT;
 
@@ -728,12 +742,9 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
 			 * so extract it only once.
 			 */
 			if (gas_t->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
-				if (pcc_data.pcc_subspace_idx < 0)
-					pcc_data.pcc_subspace_idx = gas_t->access_width;
-				else if (pcc_data.pcc_subspace_idx != gas_t->access_width) {
-					pr_debug("Mismatched PCC ids.\n");
-					goto out_free;
-				}
+				pcc_subspace_id = gas_t->access_width;
+				pcc_data[pcc_subspace_id].pcc_subspace_idx = gas_t->access_width;
+				per_cpu(cpu_pcc_subspace_idx, pr->id) = gas_t->access_width;
 			} else if (gas_t->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
 				if (gas_t->address) {
 					void __iomem *addr;
@@ -766,14 +777,14 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
 	if (ret)
 		goto out_free;
 
-	/* Register PCC channel once for all CPUs. */
-	if (!pcc_data.pcc_channel_acquired) {
-		ret = register_pcc_channel(pcc_data.pcc_subspace_idx);
+	/* Register PCC channel once for all PCC subspace id. */
+	if (!pcc_data[pcc_subspace_id].pcc_channel_acquired) {
+		ret = register_pcc_channel(pcc_data[pcc_subspace_id].pcc_subspace_idx);
 		if (ret)
 			goto out_free;
 
-		init_rwsem(&pcc_data.pcc_lock);
-		init_waitqueue_head(&pcc_data.pcc_write_wait_q);
+		init_rwsem(&pcc_data[pcc_subspace_id].pcc_lock);
+		init_waitqueue_head(&pcc_data[pcc_subspace_id].pcc_write_wait_q);
 	}
 
 	/* Everything looks okay */
@@ -883,6 +894,7 @@ static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
 {
 	int ret_val = 0;
 	void __iomem *vaddr = 0;
+	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
 	struct cpc_reg *reg = &reg_res->cpc_entry.reg;
 
 	if (reg_res->type == ACPI_TYPE_INTEGER) {
@@ -892,7 +904,7 @@ static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
 
 	*val = 0;
 	if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM)
-		vaddr = GET_PCC_VADDR(reg->address);
+		vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id);
 	else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
 		vaddr = reg_res->sys_mem_vaddr;
 	else if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE)
@@ -927,10 +939,11 @@ static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
 {
 	int ret_val = 0;
 	void __iomem *vaddr = 0;
+	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
 	struct cpc_reg *reg = &reg_res->cpc_entry.reg;
 
 	if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM)
-		vaddr = GET_PCC_VADDR(reg->address);
+		vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id);
 	else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
 		vaddr = reg_res->sys_mem_vaddr;
 	else if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE)
@@ -974,6 +987,8 @@ 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, *ref_perf,
 								 *nom_perf;
+	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
+	struct cppc_pcc_data *pcc_ss_data = &pcc_data[pcc_ss_id];
 	u64 high, low, nom;
 	int ret = 0, regs_in_pcc = 0;
 
@@ -991,9 +1006,9 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
 	if (CPC_IN_PCC(highest_reg) || CPC_IN_PCC(lowest_reg) ||
 		CPC_IN_PCC(ref_perf) || CPC_IN_PCC(nom_perf)) {
 		regs_in_pcc = 1;
-		down_write(&pcc_data.pcc_lock);
+		down_write(&pcc_ss_data->pcc_lock);
 		/* Ring doorbell once to update PCC subspace */
-		if (send_pcc_cmd(CMD_READ) < 0) {
+		if (send_pcc_cmd(cpunum, CMD_READ) < 0) {
 			ret = -EIO;
 			goto out_err;
 		}
@@ -1013,7 +1028,7 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
 
 out_err:
 	if (regs_in_pcc)
-		up_write(&pcc_data.pcc_lock);
+		up_write(&pcc_ss_data->pcc_lock);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(cppc_get_perf_caps);
@@ -1030,6 +1045,8 @@ 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;
+	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
+	struct cppc_pcc_data *pcc_ss_data = &pcc_data[pcc_ss_id];
 	u64 delivered, reference, ref_perf, ctr_wrap_time;
 	int ret = 0, regs_in_pcc = 0;
 
@@ -1053,10 +1070,10 @@ 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)) {
-		down_write(&pcc_data.pcc_lock);
+		down_write(&pcc_ss_data->pcc_lock);
 		regs_in_pcc = 1;
 		/* Ring doorbell once to update PCC subspace */
-		if (send_pcc_cmd(CMD_READ) < 0) {
+		if (send_pcc_cmd(cpunum, CMD_READ) < 0) {
 			ret = -EIO;
 			goto out_err;
 		}
@@ -1086,7 +1103,7 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
 	perf_fb_ctrs->ctr_wrap_time = ctr_wrap_time;
 out_err:
 	if (regs_in_pcc)
-		up_write(&pcc_data.pcc_lock);
+		up_write(&pcc_ss_data->pcc_lock);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);
@@ -1102,6 +1119,8 @@ 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 = &pcc_data[pcc_ss_id];
 	int ret = 0;
 
 	if (!cpc_desc) {
@@ -1119,11 +1138,11 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
 	 * achieve that goal here
 	 */
 	if (CPC_IN_PCC(desired_reg)) {
-		down_read(&pcc_data.pcc_lock);	/* BEGIN Phase-I */
-		if (pcc_data.platform_owns_pcc) {
-			ret = check_pcc_chan(false);
+		down_read(&pcc_ss_data->pcc_lock); /* BEGIN Phase-I */
+		if (pcc_ss_data->platform_owns_pcc) {
+			ret = check_pcc_chan(cpu, false);
 			if (ret) {
-				up_read(&pcc_data.pcc_lock);
+				up_read(&pcc_ss_data->pcc_lock);
 				return ret;
 			}
 		}
@@ -1131,8 +1150,8 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
 		 * Update the pending_write to make sure a PCC CMD_READ will not
 		 * arrive and steal the channel during the switch to write lock
 		 */
-		pcc_data.pending_pcc_write_cmd = true;
-		cpc_desc->write_cmd_id = pcc_data.pcc_write_cnt;
+		pcc_ss_data->pending_pcc_write_cmd = true;
+		cpc_desc->write_cmd_id = pcc_ss_data->pcc_write_cnt;
 		cpc_desc->write_cmd_status = 0;
 	}
 
@@ -1143,7 +1162,7 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
 	cpc_write(cpu, desired_reg, perf_ctrls->desired_perf);
 
 	if (CPC_IN_PCC(desired_reg))
-		up_read(&pcc_data.pcc_lock);	/* END Phase-I */
+		up_read(&pcc_ss_data->pcc_lock);	/* END Phase-I */
 	/*
 	 * This is Phase-II where we transfer the ownership of PCC to Platform
 	 *
@@ -1191,15 +1210,15 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
 	 * the write command before servicing the read command
 	 */
 	if (CPC_IN_PCC(desired_reg)) {
-		if (down_write_trylock(&pcc_data.pcc_lock)) {	/* BEGIN Phase-II */
+		if (down_write_trylock(&pcc_ss_data->pcc_lock)) {/* BEGIN Phase-II */
 			/* Update only if there are pending write commands */
-			if (pcc_data.pending_pcc_write_cmd)
-				send_pcc_cmd(CMD_WRITE);
-			up_write(&pcc_data.pcc_lock);		/* END Phase-II */
+			if (pcc_ss_data->pending_pcc_write_cmd)
+				send_pcc_cmd(cpu, CMD_WRITE);
+			up_write(&pcc_ss_data->pcc_lock);	/* END Phase-II */
 		} else
 			/* Wait until pcc_write_cnt is updated by send_pcc_cmd */
-			wait_event(pcc_data.pcc_write_wait_q,
-				cpc_desc->write_cmd_id != pcc_data.pcc_write_cnt);
+			wait_event(pcc_ss_data->pcc_write_wait_q,
+				   cpc_desc->write_cmd_id != pcc_ss_data->pcc_write_cnt);
 
 		/* send_pcc_cmd updates the status in case of failure */
 		ret = cpc_desc->write_cmd_status;
@@ -1232,6 +1251,8 @@ unsigned int cppc_get_transition_latency(int cpu_num)
 	unsigned int latency_ns = 0;
 	struct cpc_desc *cpc_desc;
 	struct cpc_register_resource *desired_reg;
+	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu_num);
+	struct cppc_pcc_data *pcc_ss_data = &pcc_data[pcc_ss_id];
 
 	cpc_desc = per_cpu(cpc_desc_ptr, cpu_num);
 	if (!cpc_desc)
@@ -1241,11 +1262,11 @@ unsigned int cppc_get_transition_latency(int cpu_num)
 	if (!CPC_IN_PCC(desired_reg))
 		return CPUFREQ_ETERNAL;
 
-	if (pcc_data.pcc_mpar)
-		latency_ns = 60 * (1000 * 1000 * 1000 / pcc_data.pcc_mpar);
+	if (pcc_ss_data->pcc_mpar)
+		latency_ns = 60 * (1000 * 1000 * 1000 / pcc_ss_data->pcc_mpar);
 
-	latency_ns = max(latency_ns, pcc_data.pcc_nominal * 1000);
-	latency_ns = max(latency_ns, pcc_data.pcc_mrtt * 1000);
+	latency_ns = max(latency_ns, pcc_ss_data->pcc_nominal * 1000);
+	latency_ns = max(latency_ns, pcc_ss_data->pcc_mrtt * 1000);
 
 	return latency_ns;
 }
-- 
2.1.4