Merge branches 'acpi-x86', 'acpi-cppc' and 'acpi-soc'

* acpi-x86:
  x86: ACPI: make variable names clearer in acpi_parse_madt_lapic_entries()
  x86: ACPI: remove extraneous white space after semicolon

* acpi-cppc:
  ACPI / CPPC: Support PCC with interrupt flag
  ACPI / CPPC: Add prefix cppc to cpudata structure name
  ACPI / CPPC: Add support for functional fixed hardware address
  ACPI / CPPC: Don't return on CPPC probe failure
  ACPI / CPPC: Allow build with ACPI_CPU_FREQ_PSS config
  ACPI / CPPC: check for error bit in PCC status field
  ACPI / CPPC: move all PCC related information into pcc_data
  ACPI / CPPC: add sysfs support to compute delivered performance
  ACPI / CPPC: set a non-zero value for transition_latency
  ACPI / CPPC: support for batching CPPC requests
  ACPI / CPPC: acquire pcc_lock only while accessing PCC subspace
  ACPI / CPPC: restructure read/writes for efficient sys mapped reg ops
  mailbox: pcc: Support HW-Reduced Communication Subspace type 2

* acpi-soc:
  ACPI / APD: constify local structures
  ACPI / APD: Add device HID for Vulcan SPI controller

arch/x86/kernel/acpi/Makefile

@@ -1,6 +1,7 @@
 obj-$(CONFIG_ACPI)		+= boot.o
 obj-$(CONFIG_ACPI_SLEEP)	+= sleep.o wakeup_$(BITS).o
 obj-$(CONFIG_ACPI_APEI)		+= apei.o
+obj-$(CONFIG_ACPI_CPPC_LIB)	+= cppc_msr.o
 
 ifneq ($(CONFIG_ACPI_PROCESSOR),)
 obj-y				+= cstate.o

arch/x86/kernel/acpi/boot.c

@@ -1031,8 +1031,8 @@ static int __init acpi_parse_madt_lapic_entries(void)
 			return ret;
 		}
 
-		x2count = madt_proc[0].count;
-		count = madt_proc[1].count;
+		count = madt_proc[0].count;
+		x2count = madt_proc[1].count;
 	}
 	if (!count && !x2count) {
 		printk(KERN_ERR PREFIX "No LAPIC entries present\n");
@@ -1513,7 +1513,7 @@ void __init acpi_boot_table_init(void)
 	 * If acpi_disabled, bail out
 	 */
 	if (acpi_disabled)
-		return; 
+		return;
 
 	/*
 	 * Initialize the ACPI boot-time table parser.

arch/x86/kernel/acpi/cppc_msr.c

@@ -0,0 +1,58 @@
+/*
+ * cppc_msr.c:  MSR Interface for CPPC
+ * Copyright (c) 2016, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include <acpi/cppc_acpi.h>
+#include <asm/msr.h>
+
+/* Refer to drivers/acpi/cppc_acpi.c for the description of functions */
+
+bool cpc_ffh_supported(void)
+{
+	return true;
+}
+
+int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val)
+{
+	int err;
+
+	err = rdmsrl_safe_on_cpu(cpunum, reg->address, val);
+	if (!err) {
+		u64 mask = GENMASK_ULL(reg->bit_offset + reg->bit_width - 1,
+				       reg->bit_offset);
+
+		*val &= mask;
+		*val >>= reg->bit_offset;
+	}
+	return err;
+}
+
+int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val)
+{
+	u64 rd_val;
+	int err;
+
+	err = rdmsrl_safe_on_cpu(cpunum, reg->address, &rd_val);
+	if (!err) {
+		u64 mask = GENMASK_ULL(reg->bit_offset + reg->bit_width - 1,
+				       reg->bit_offset);
+
+		val <<= reg->bit_offset;
+		val &= mask;
+		rd_val &= ~mask;
+		rd_val |= val;
+		err = wrmsrl_safe_on_cpu(cpunum, reg->address, rd_val);
+	}
+	return err;
+}

drivers/acpi/Kconfig

@@ -227,7 +227,6 @@ config ACPI_MCFG
 config ACPI_CPPC_LIB
 	bool
 	depends on ACPI_PROCESSOR
-	depends on !ACPI_CPU_FREQ_PSS
 	select MAILBOX
 	select PCC
 	help

drivers/acpi/acpi_apd.c

@@ -72,7 +72,7 @@ static int acpi_apd_setup(struct apd_private_data *pdata)
 }
 
 #ifdef CONFIG_X86_AMD_PLATFORM_DEVICE
-static struct apd_device_desc cz_i2c_desc = {
+static const struct apd_device_desc cz_i2c_desc = {
 	.setup = acpi_apd_setup,
 	.fixed_clk_rate = 133000000,
 };
@@ -84,7 +84,7 @@ static struct property_entry uart_properties[] = {
 	{ },
 };
 
-static struct apd_device_desc cz_uart_desc = {
+static const struct apd_device_desc cz_uart_desc = {
 	.setup = acpi_apd_setup,
 	.fixed_clk_rate = 48000000,
 	.properties = uart_properties,
@@ -92,10 +92,15 @@ static struct apd_device_desc cz_uart_desc = {
 #endif
 
 #ifdef CONFIG_ARM64
-static struct apd_device_desc xgene_i2c_desc = {
+static const struct apd_device_desc xgene_i2c_desc = {
 	.setup = acpi_apd_setup,
 	.fixed_clk_rate = 100000000,
 };
+
+static const struct apd_device_desc vulcan_spi_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 133000000,
+};
 #endif
 
 #else
@@ -164,6 +169,7 @@ static const struct acpi_device_id acpi_apd_device_ids[] = {
 #endif
 #ifdef CONFIG_ARM64
 	{ "APMC0D0F", APD_ADDR(xgene_i2c_desc) },
+	{ "BRCM900D", APD_ADDR(vulcan_spi_desc) },
 #endif
 	{ }
 };

drivers/acpi/cppc_acpi.c

@@ -40,15 +40,48 @@
 #include <linux/cpufreq.h>
 #include <linux/delay.h>
 #include <linux/ktime.h>
+#include <linux/rwsem.h>
+#include <linux/wait.h>
 
 #include <acpi/cppc_acpi.h>
-/*
- * Lock to provide mutually exclusive access to the PCC
- * channel. e.g. When the remote updates the shared region
- * with new data, the reader needs to be protected from
- * other CPUs activity on the same channel.
- */
-static DEFINE_SPINLOCK(pcc_lock);
+
+struct cppc_pcc_data {
+	struct mbox_chan *pcc_channel;
+	void __iomem *pcc_comm_addr;
+	int pcc_subspace_idx;
+	bool pcc_channel_acquired;
+	ktime_t deadline;
+	unsigned int pcc_mpar, pcc_mrtt, pcc_nominal;
+
+	bool pending_pcc_write_cmd;	/* Any pending/batched PCC write cmds? */
+	bool platform_owns_pcc;		/* Ownership of PCC subspace */
+	unsigned int pcc_write_cnt;	/* Running count of PCC write commands */
+
+	/*
+	 * Lock to provide controlled access to the PCC channel.
+	 *
+	 * For performance critical usecases(currently cppc_set_perf)
+	 *	We need to take read_lock and check if channel belongs to OSPM
+	 * before reading or writing to PCC subspace
+	 *	We need to take write_lock before transferring the channel
+	 * ownership to the platform via a Doorbell
+	 *	This allows us to batch a number of CPPC requests if they happen
+	 * to originate in about the same time
+	 *
+	 * For non-performance critical usecases(init)
+	 *	Take write_lock for all purposes which gives exclusive access
+	 */
+	struct rw_semaphore pcc_lock;
+
+	/* Wait queue for CPUs whose requests were batched */
+	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,
+};
 
 /*
  * The cpc_desc structure contains the ACPI register details
@@ -59,18 +92,25 @@ static DEFINE_SPINLOCK(pcc_lock);
  */
 static DEFINE_PER_CPU(struct cpc_desc *, cpc_desc_ptr);
 
-/* This layer handles all the PCC specifics for CPPC. */
-static struct mbox_chan *pcc_channel;
-static void __iomem *pcc_comm_addr;
-static u64 comm_base_addr;
-static int pcc_subspace_idx = -1;
-static bool pcc_channel_acquired;
-static ktime_t deadline;
-static unsigned int pcc_mpar, pcc_mrtt;
-
 /* pcc mapped address + header size + offset within PCC subspace */
-#define GET_PCC_VADDR(offs) (pcc_comm_addr + 0x8 + (offs))
-
+#define GET_PCC_VADDR(offs) (pcc_data.pcc_comm_addr + 0x8 + (offs))
+
+/* Check if a CPC regsiter is in PCC */
+#define CPC_IN_PCC(cpc) ((cpc)->type == ACPI_TYPE_BUFFER &&		\
+				(cpc)->cpc_entry.reg.space_id ==	\
+				ACPI_ADR_SPACE_PLATFORM_COMM)
+
+/* Evalutes to True if reg is a NULL register descriptor */
+#define IS_NULL_REG(reg) ((reg)->space_id ==  ACPI_ADR_SPACE_SYSTEM_MEMORY && \
+				(reg)->address == 0 &&			\
+				(reg)->bit_width == 0 &&		\
+				(reg)->bit_offset == 0 &&		\
+				(reg)->access_width == 0)
+
+/* Evalutes to True if an optional cpc field is supported */
+#define CPC_SUPPORTED(cpc) ((cpc)->type == ACPI_TYPE_INTEGER ?		\
+				!!(cpc)->cpc_entry.int_value :		\
+				!IS_NULL_REG(&(cpc)->cpc_entry.reg))
 /*
  * Arbitrary Retries in case the remote processor is slow to respond
  * to PCC commands. Keeping it high enough to cover emulators where
@@ -78,11 +118,79 @@ static unsigned int pcc_mpar, pcc_mrtt;
  */
 #define NUM_RETRIES 500
 
-static int check_pcc_chan(void)
+struct cppc_attr {
+	struct attribute attr;
+	ssize_t (*show)(struct kobject *kobj,
+			struct attribute *attr, char *buf);
+	ssize_t (*store)(struct kobject *kobj,
+			struct attribute *attr, const char *c, ssize_t count);
+};
+
+#define define_one_cppc_ro(_name)		\
+static struct cppc_attr _name =			\
+__ATTR(_name, 0444, show_##_name, NULL)
+
+#define to_cpc_desc(a) container_of(a, struct cpc_desc, kobj)
+
+static ssize_t show_feedback_ctrs(struct kobject *kobj,
+		struct attribute *attr, char *buf)
+{
+	struct cpc_desc *cpc_ptr = to_cpc_desc(kobj);
+	struct cppc_perf_fb_ctrs fb_ctrs = {0};
+
+	cppc_get_perf_ctrs(cpc_ptr->cpu_id, &fb_ctrs);
+
+	return scnprintf(buf, PAGE_SIZE, "ref:%llu del:%llu\n",
+			fb_ctrs.reference, fb_ctrs.delivered);
+}
+define_one_cppc_ro(feedback_ctrs);
+
+static ssize_t show_reference_perf(struct kobject *kobj,
+		struct attribute *attr, char *buf)
+{
+	struct cpc_desc *cpc_ptr = to_cpc_desc(kobj);
+	struct cppc_perf_fb_ctrs fb_ctrs = {0};
+
+	cppc_get_perf_ctrs(cpc_ptr->cpu_id, &fb_ctrs);
+
+	return scnprintf(buf, PAGE_SIZE, "%llu\n",
+			fb_ctrs.reference_perf);
+}
+define_one_cppc_ro(reference_perf);
+
+static ssize_t show_wraparound_time(struct kobject *kobj,
+				struct attribute *attr, char *buf)
+{
+	struct cpc_desc *cpc_ptr = to_cpc_desc(kobj);
+	struct cppc_perf_fb_ctrs fb_ctrs = {0};
+
+	cppc_get_perf_ctrs(cpc_ptr->cpu_id, &fb_ctrs);
+
+	return scnprintf(buf, PAGE_SIZE, "%llu\n", fb_ctrs.ctr_wrap_time);
+
+}
+define_one_cppc_ro(wraparound_time);
+
+static struct attribute *cppc_attrs[] = {
+	&feedback_ctrs.attr,
+	&reference_perf.attr,
+	&wraparound_time.attr,
+	NULL
+};
+
+static struct kobj_type cppc_ktype = {
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_attrs = cppc_attrs,
+};
+
+static int check_pcc_chan(bool chk_err_bit)
 {
-	int ret = -EIO;
-	struct acpi_pcct_shared_memory __iomem *generic_comm_base = pcc_comm_addr;
-	ktime_t next_deadline = ktime_add(ktime_get(), deadline);
+	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)
+		return 0;
 
 	/* Retry in case the remote processor was too slow to catch up. */
 	while (!ktime_after(ktime_get(), next_deadline)) {
@@ -91,8 +199,11 @@ static int check_pcc_chan(void)
 		 * platform and should have set the command completion bit when
 		 * PCC can be used by OSPM
 		 */
-		if (readw_relaxed(&generic_comm_base->status) & PCC_CMD_COMPLETE) {
+		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;
 		}
 		/*
@@ -102,14 +213,23 @@ static int check_pcc_chan(void)
 		udelay(3);
 	}
 
+	if (likely(!ret))
+		pcc_data.platform_owns_pcc = false;
+	else
+		pr_err("PCC check channel failed. Status=%x\n", status);
+
 	return ret;
 }
 
+/*
+ * 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)
 {
-	int ret = -EIO;
+	int ret = -EIO, i;
 	struct acpi_pcct_shared_memory *generic_comm_base =
-		(struct acpi_pcct_shared_memory *) pcc_comm_addr;
+		(struct acpi_pcct_shared_memory *) pcc_data.pcc_comm_addr;
 	static ktime_t last_cmd_cmpl_time, last_mpar_reset;
 	static int mpar_count;
 	unsigned int time_delta;
@@ -119,20 +239,29 @@ static int send_pcc_cmd(u16 cmd)
 	 * the channel before writing to PCC space
 	 */
 	if (cmd == CMD_READ) {
-		ret = check_pcc_chan();
+		/*
+		 * If there are pending cpc_writes, then we stole the channel
+		 * before write completion, so first send a WRITE command to
+		 * platform
+		 */
+		if (pcc_data.pending_pcc_write_cmd)
+			send_pcc_cmd(CMD_WRITE);
+
+		ret = check_pcc_chan(false);
 		if (ret)
-			return ret;
-	}
+			goto end;
+	} else /* CMD_WRITE */
+		pcc_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_mrtt) {
+	if (pcc_data.pcc_mrtt) {
 		time_delta = ktime_us_delta(ktime_get(), last_cmd_cmpl_time);
-		if (pcc_mrtt > time_delta)
-			udelay(pcc_mrtt - time_delta);
+		if (pcc_data.pcc_mrtt > time_delta)
+			udelay(pcc_data.pcc_mrtt - time_delta);
 	}
 
 	/*
@@ -146,15 +275,16 @@ 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_mpar) {
+	if (pcc_data.pcc_mpar) {
 		if (mpar_count == 0) {
 			time_delta = ktime_ms_delta(ktime_get(), last_mpar_reset);
 			if (time_delta < 60 * MSEC_PER_SEC) {
 				pr_debug("PCC cmd not sent due to MPAR limit");
-				return -EIO;
+				ret = -EIO;
+				goto end;
 			}
 			last_mpar_reset = ktime_get();
-			mpar_count = pcc_mpar;
+			mpar_count = pcc_data.pcc_mpar;
 		}
 		mpar_count--;
 	}
@@ -165,33 +295,43 @@ static int send_pcc_cmd(u16 cmd)
 	/* Flip CMD COMPLETE bit */
 	writew_relaxed(0, &generic_comm_base->status);
 
+	pcc_data.platform_owns_pcc = true;
+
 	/* Ring doorbell */
-	ret = mbox_send_message(pcc_channel, &cmd);
+	ret = mbox_send_message(pcc_data.pcc_channel, &cmd);
 	if (ret < 0) {
 		pr_err("Err sending PCC mbox message. cmd:%d, ret:%d\n",
 				cmd, ret);
-		return ret;
+		goto end;
 	}
 
-	/*
-	 * For READs we need to ensure the cmd completed to ensure
-	 * the ensuing read()s can proceed. For WRITEs we dont care
-	 * because the actual write()s are done before coming here
-	 * and the next READ or WRITE will check if the channel
-	 * is busy/free at the entry of this call.
-	 *
-	 * If Minimum Request Turnaround Time is non-zero, we need
-	 * to record the completion time of both READ and WRITE
-	 * command for proper handling of MRTT, so we need to check
-	 * for pcc_mrtt in addition to CMD_READ
-	 */
-	if (cmd == CMD_READ || pcc_mrtt) {
-		ret = check_pcc_chan();
-		if (pcc_mrtt)
-			last_cmd_cmpl_time = ktime_get();
+	/* wait for completion and check for PCC errro bit */
+	ret = check_pcc_chan(true);
+
+	if (pcc_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);
+	else
+		mbox_client_txdone(pcc_data.pcc_channel, ret);
+
+end:
+	if (cmd == CMD_WRITE) {
+		if (unlikely(ret)) {
+			for_each_possible_cpu(i) {
+				struct cpc_desc *desc = per_cpu(cpc_desc_ptr, i);
+				if (!desc)
+					continue;
+
+				if (desc->write_cmd_id == pcc_data.pcc_write_cnt)
+					desc->write_cmd_status = ret;
+			}
+		}
+		pcc_data.pcc_write_cnt++;
+		wake_up_all(&pcc_data.pcc_write_wait_q);
 	}
 
-	mbox_client_txdone(pcc_channel, ret);
 	return ret;
 }
 
@@ -272,13 +412,13 @@ end:
  *
  *	Return: 0 for success or negative value for err.
  */
-int acpi_get_psd_map(struct cpudata **all_cpu_data)
+int acpi_get_psd_map(struct cppc_cpudata **all_cpu_data)
 {
 	int count_target;
 	int retval = 0;
 	unsigned int i, j;
 	cpumask_var_t covered_cpus;
-	struct cpudata *pr, *match_pr;
+	struct cppc_cpudata *pr, *match_pr;
 	struct acpi_psd_package *pdomain;
 	struct acpi_psd_package *match_pdomain;
 	struct cpc_desc *cpc_ptr, *match_cpc_ptr;
@@ -394,14 +534,13 @@ EXPORT_SYMBOL_GPL(acpi_get_psd_map);
 static int register_pcc_channel(int pcc_subspace_idx)
 {
 	struct acpi_pcct_hw_reduced *cppc_ss;
-	unsigned int len;
 	u64 usecs_lat;
 
 	if (pcc_subspace_idx >= 0) {
-		pcc_channel = pcc_mbox_request_channel(&cppc_mbox_cl,
+		pcc_data.pcc_channel = pcc_mbox_request_channel(&cppc_mbox_cl,
 				pcc_subspace_idx);
 
-		if (IS_ERR(pcc_channel)) {
+		if (IS_ERR(pcc_data.pcc_channel)) {
 			pr_err("Failed to find PCC communication channel\n");
 			return -ENODEV;
 		}
@@ -412,43 +551,50 @@ 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_channel->con_priv;
+		cppc_ss = (pcc_data.pcc_channel)->con_priv;
 
 		if (!cppc_ss) {
 			pr_err("No PCC subspace found for CPPC\n");
 			return -ENODEV;
 		}
 
-		/*
-		 * This is the shared communication region
-		 * for the OS and Platform to communicate over.
-		 */
-		comm_base_addr = cppc_ss->base_address;
-		len = cppc_ss->length;
-
 		/*
 		 * cppc_ss->latency is just a Nominal value. In reality
 		 * the remote processor could be much slower to reply.
 		 * So add an arbitrary amount of wait on top of Nominal.
 		 */
 		usecs_lat = NUM_RETRIES * cppc_ss->latency;
-		deadline = ns_to_ktime(usecs_lat * NSEC_PER_USEC);
-		pcc_mrtt = cppc_ss->min_turnaround_time;
-		pcc_mpar = cppc_ss->max_access_rate;
+		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_comm_addr = acpi_os_ioremap(comm_base_addr, len);
-		if (!pcc_comm_addr) {
+		pcc_data.pcc_comm_addr = acpi_os_ioremap(cppc_ss->base_address, cppc_ss->length);
+		if (!pcc_data.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_channel_acquired = true;
+		pcc_data.pcc_channel_acquired = true;
 	}
 
 	return 0;
 }
 
+/**
+ * cpc_ffh_supported() - check if FFH reading supported
+ *
+ * Check if the architecture has support for functional fixed hardware
+ * read/write capability.
+ *
+ * Return: true for supported, false for not supported
+ */
+bool __weak cpc_ffh_supported(void)
+{
+	return false;
+}
+
 /*
  * An example CPC table looks like the following.
  *
@@ -507,6 +653,7 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
 	union acpi_object *out_obj, *cpc_obj;
 	struct cpc_desc *cpc_ptr;
 	struct cpc_reg *gas_t;
+	struct device *cpu_dev;
 	acpi_handle handle = pr->handle;
 	unsigned int num_ent, i, cpc_rev;
 	acpi_status status;
@@ -545,6 +692,8 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
 		goto out_free;
 	}
 
+	cpc_ptr->num_entries = num_ent;
+
 	/* Second entry should be revision. */
 	cpc_obj = &out_obj->package.elements[1];
 	if (cpc_obj->type == ACPI_TYPE_INTEGER)	{
@@ -579,16 +728,27 @@ 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_subspace_idx < 0)
-					pcc_subspace_idx = gas_t->access_width;
-				else if (pcc_subspace_idx != gas_t->access_width) {
+				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;
 				}
-			} else if (gas_t->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) {
-				/* Support only PCC and SYS MEM type regs */
-				pr_debug("Unsupported register type: %d\n", gas_t->space_id);
-				goto out_free;
+			} else if (gas_t->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
+				if (gas_t->address) {
+					void __iomem *addr;
+
+					addr = ioremap(gas_t->address, gas_t->bit_width/8);
+					if (!addr)
+						goto out_free;
+					cpc_ptr->cpc_regs[i-2].sys_mem_vaddr = addr;
+				}
+			} else {
+				if (gas_t->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE || !cpc_ffh_supported()) {
+					/* Support only PCC ,SYS MEM and FFH type regs */
+					pr_debug("Unsupported register type: %d\n", gas_t->space_id);
+					goto out_free;
+				}
 			}
 
 			cpc_ptr->cpc_regs[i-2].type = ACPI_TYPE_BUFFER;
@@ -607,10 +767,13 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
 		goto out_free;
 
 	/* Register PCC channel once for all CPUs. */
-	if (!pcc_channel_acquired) {
-		ret = register_pcc_channel(pcc_subspace_idx);
+	if (!pcc_data.pcc_channel_acquired) {
+		ret = register_pcc_channel(pcc_data.pcc_subspace_idx);
 		if (ret)
 			goto out_free;
+
+		init_rwsem(&pcc_data.pcc_lock);
+		init_waitqueue_head(&pcc_data.pcc_write_wait_q);
 	}
 
 	/* Plug PSD data into this CPUs CPC descriptor. */
@@ -619,10 +782,27 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
 	/* Everything looks okay */
 	pr_debug("Parsed CPC struct for CPU: %d\n", pr->id);
 
+	/* Add per logical CPU nodes for reading its feedback counters. */
+	cpu_dev = get_cpu_device(pr->id);
+	if (!cpu_dev)
+		goto out_free;
+
+	ret = kobject_init_and_add(&cpc_ptr->kobj, &cppc_ktype, &cpu_dev->kobj,
+			"acpi_cppc");
+	if (ret)
+		goto out_free;
+
 	kfree(output.pointer);
 	return 0;
 
 out_free:
+	/* Free all the mapped sys mem areas for this CPU */
+	for (i = 2; i < cpc_ptr->num_entries; i++) {
+		void __iomem *addr = cpc_ptr->cpc_regs[i-2].sys_mem_vaddr;
+
+		if (addr)
+			iounmap(addr);
+	}
 	kfree(cpc_ptr);
 
 out_buf_free:
@@ -640,26 +820,82 @@ EXPORT_SYMBOL_GPL(acpi_cppc_processor_probe);
 void acpi_cppc_processor_exit(struct acpi_processor *pr)
 {
 	struct cpc_desc *cpc_ptr;
+	unsigned int i;
+	void __iomem *addr;
+
 	cpc_ptr = per_cpu(cpc_desc_ptr, pr->id);
+
+	/* Free all the mapped sys mem areas for this CPU */
+	for (i = 2; i < cpc_ptr->num_entries; i++) {
+		addr = cpc_ptr->cpc_regs[i-2].sys_mem_vaddr;
+		if (addr)
+			iounmap(addr);
+	}
+
+	kobject_put(&cpc_ptr->kobj);
 	kfree(cpc_ptr);
 }
 EXPORT_SYMBOL_GPL(acpi_cppc_processor_exit);
 
+/**
+ * cpc_read_ffh() - Read FFH register
+ * @cpunum:	cpu number to read
+ * @reg:	cppc register information
+ * @val:	place holder for return value
+ *
+ * Read bit_width bits from a specified address and bit_offset
+ *
+ * Return: 0 for success and error code
+ */
+int __weak cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val)
+{
+	return -ENOTSUPP;
+}
+
+/**
+ * cpc_write_ffh() - Write FFH register
+ * @cpunum:	cpu number to write
+ * @reg:	cppc register information
+ * @val:	value to write
+ *
+ * Write value of bit_width bits to a specified address and bit_offset
+ *
+ * Return: 0 for success and error code
+ */
+int __weak cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val)
+{
+	return -ENOTSUPP;
+}
+
 /*
  * Since cpc_read and cpc_write are called while holding pcc_lock, it should be
  * as fast as possible. We have already mapped the PCC subspace during init, so
  * we can directly write to it.
  */
 
-static int cpc_read(struct cpc_reg *reg, u64 *val)
+static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
 {
 	int ret_val = 0;
+	void __iomem *vaddr = 0;
+	struct cpc_reg *reg = &reg_res->cpc_entry.reg;
+
+	if (reg_res->type == ACPI_TYPE_INTEGER) {
+		*val = reg_res->cpc_entry.int_value;
+		return ret_val;
+	}
 
 	*val = 0;
-	if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
-		void __iomem *vaddr = GET_PCC_VADDR(reg->address);
+	if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM)
+		vaddr = GET_PCC_VADDR(reg->address);
+	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)
+		return cpc_read_ffh(cpu, reg, val);
+	else
+		return acpi_os_read_memory((acpi_physical_address)reg->address,
+				val, reg->bit_width);
 
-		switch (reg->bit_width) {
+	switch (reg->bit_width) {
 		case 8:
 			*val = readb_relaxed(vaddr);
 			break;
@@ -674,23 +910,30 @@ static int cpc_read(struct cpc_reg *reg, u64 *val)
 			break;
 		default:
 			pr_debug("Error: Cannot read %u bit width from PCC\n",
-				reg->bit_width);
+					reg->bit_width);
 			ret_val = -EFAULT;
-		}
-	} else
-		ret_val = acpi_os_read_memory((acpi_physical_address)reg->address,
-					val, reg->bit_width);
+	}
+
 	return ret_val;
 }
 
-static int cpc_write(struct cpc_reg *reg, u64 val)
+static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
 {
 	int ret_val = 0;
+	void __iomem *vaddr = 0;
+	struct cpc_reg *reg = &reg_res->cpc_entry.reg;
+
+	if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM)
+		vaddr = GET_PCC_VADDR(reg->address);
+	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)
+		return cpc_write_ffh(cpu, reg, val);
+	else
+		return acpi_os_write_memory((acpi_physical_address)reg->address,
+				val, reg->bit_width);
 
-	if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
-		void __iomem *vaddr = GET_PCC_VADDR(reg->address);
-
-		switch (reg->bit_width) {
+	switch (reg->bit_width) {
 		case 8:
 			writeb_relaxed(val, vaddr);
 			break;
@@ -705,13 +948,11 @@ static int cpc_write(struct cpc_reg *reg, u64 val)
 			break;
 		default:
 			pr_debug("Error: Cannot write %u bit width to PCC\n",
-				reg->bit_width);
+					reg->bit_width);
 			ret_val = -EFAULT;
 			break;
-		}
-	} else
-		ret_val = acpi_os_write_memory((acpi_physical_address)reg->address,
-				val, reg->bit_width);
+	}
+
 	return ret_val;
 }
 
@@ -727,8 +968,8 @@ 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;
-	u64 high, low, ref, nom;
-	int ret = 0;
+	u64 high, low, nom;
+	int ret = 0, regs_in_pcc = 0;
 
 	if (!cpc_desc) {
 		pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
@@ -740,13 +981,11 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
 	ref_perf = &cpc_desc->cpc_regs[REFERENCE_PERF];
 	nom_perf = &cpc_desc->cpc_regs[NOMINAL_PERF];
 
-	spin_lock(&pcc_lock);
-
 	/* Are any of the regs PCC ?*/
-	if ((highest_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) ||
-			(lowest_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) ||
-			(ref_perf->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) ||
-			(nom_perf->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM)) {
+	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);
 		/* Ring doorbell once to update PCC subspace */
 		if (send_pcc_cmd(CMD_READ) < 0) {
 			ret = -EIO;
@@ -754,26 +993,21 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
 		}
 	}
 
-	cpc_read(&highest_reg->cpc_entry.reg, &high);
+	cpc_read(cpunum, highest_reg, &high);
 	perf_caps->highest_perf = high;
 
-	cpc_read(&lowest_reg->cpc_entry.reg, &low);
+	cpc_read(cpunum, lowest_reg, &low);
 	perf_caps->lowest_perf = low;
 
-	cpc_read(&ref_perf->cpc_entry.reg, &ref);
-	perf_caps->reference_perf = ref;
-
-	cpc_read(&nom_perf->cpc_entry.reg, &nom);
+	cpc_read(cpunum, nom_perf, &nom);
 	perf_caps->nominal_perf = nom;
 
-	if (!ref)
-		perf_caps->reference_perf = perf_caps->nominal_perf;
-
 	if (!high || !low || !nom)
 		ret = -EFAULT;
 
 out_err:
-	spin_unlock(&pcc_lock);
+	if (regs_in_pcc)
+		up_write(&pcc_data.pcc_lock);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(cppc_get_perf_caps);
@@ -788,9 +1022,10 @@ EXPORT_SYMBOL_GPL(cppc_get_perf_caps);
 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;
-	u64 delivered, reference;
-	int ret = 0;
+	struct cpc_register_resource *delivered_reg, *reference_reg,
+		*ref_perf_reg, *ctr_wrap_reg;
+	u64 delivered, reference, ref_perf, ctr_wrap_time;
+	int ret = 0, regs_in_pcc = 0;
 
 	if (!cpc_desc) {
 		pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
@@ -799,12 +1034,21 @@ 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];
 
-	spin_lock(&pcc_lock);
+	/*
+	 * If refernce 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 ((delivered_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) ||
-			(reference_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM)) {
+	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);
+		regs_in_pcc = 1;
 		/* Ring doorbell once to update PCC subspace */
 		if (send_pcc_cmd(CMD_READ) < 0) {
 			ret = -EIO;
@@ -812,25 +1056,31 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
 		}
 	}
 
-	cpc_read(&delivered_reg->cpc_entry.reg, &delivered);
-	cpc_read(&reference_reg->cpc_entry.reg, &reference);
+	cpc_read(cpunum, delivered_reg, &delivered);
+	cpc_read(cpunum, reference_reg, &reference);
+	cpc_read(cpunum, ref_perf_reg, &ref_perf);
 
-	if (!delivered || !reference) {
+	/*
+	 * Per spec, if ctr_wrap_time optional register is unsupported, then the
+	 * performance counters are assumed to never wrap during the lifetime of
+	 * platform
+	 */
+	ctr_wrap_time = (u64)(~((u64)0));
+	if (CPC_SUPPORTED(ctr_wrap_reg))
+		cpc_read(cpunum, ctr_wrap_reg, &ctr_wrap_time);
+
+	if (!delivered || !reference ||	!ref_perf) {
 		ret = -EFAULT;
 		goto out_err;
 	}
 
 	perf_fb_ctrs->delivered = delivered;
 	perf_fb_ctrs->reference = reference;
-
-	perf_fb_ctrs->delivered -= perf_fb_ctrs->prev_delivered;
-	perf_fb_ctrs->reference -= perf_fb_ctrs->prev_reference;
-
-	perf_fb_ctrs->prev_delivered = delivered;
-	perf_fb_ctrs->prev_reference = reference;
-
+	perf_fb_ctrs->reference_perf = ref_perf;
+	perf_fb_ctrs->ctr_wrap_time = ctr_wrap_time;
 out_err:
-	spin_unlock(&pcc_lock);
+	if (regs_in_pcc)
+		up_write(&pcc_data.pcc_lock);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);
@@ -855,30 +1105,142 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
 
 	desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
 
-	spin_lock(&pcc_lock);
-
-	/* If this is PCC reg, check if channel is free before writing */
-	if (desired_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
-		ret = check_pcc_chan();
-		if (ret)
-			goto busy_channel;
+	/*
+	 * This is Phase-I where we want to write to CPC registers
+	 * -> We want all CPUs to be able to execute this phase in parallel
+	 *
+	 * Since read_lock can be acquired by multiple CPUs simultaneously we
+	 * 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);
+			if (ret) {
+				up_read(&pcc_data.pcc_lock);
+				return ret;
+			}
+		}
+		/*
+		 * 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;
+		cpc_desc->write_cmd_status = 0;
 	}
 
 	/*
 	 * Skip writing MIN/MAX until Linux knows how to come up with
 	 * useful values.
 	 */
-	cpc_write(&desired_reg->cpc_entry.reg, perf_ctrls->desired_perf);
+	cpc_write(cpu, desired_reg, perf_ctrls->desired_perf);
 
-	/* Is this a PCC reg ?*/
-	if (desired_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
-		/* Ring doorbell so Remote can get our perf request. */
-		if (send_pcc_cmd(CMD_WRITE) < 0)
-			ret = -EIO;
+	if (CPC_IN_PCC(desired_reg))
+		up_read(&pcc_data.pcc_lock);	/* END Phase-I */
+	/*
+	 * This is Phase-II where we transfer the ownership of PCC to Platform
+	 *
+	 * Short Summary: Basically if we think of a group of cppc_set_perf
+	 * requests that happened in short overlapping interval. The last CPU to
+	 * come out of Phase-I will enter Phase-II and ring the doorbell.
+	 *
+	 * We have the following requirements for Phase-II:
+	 *     1. We want to execute Phase-II only when there are no CPUs
+	 * currently executing in Phase-I
+	 *     2. Once we start Phase-II we want to avoid all other CPUs from
+	 * entering Phase-I.
+	 *     3. We want only one CPU among all those who went through Phase-I
+	 * to run phase-II
+	 *
+	 * If write_trylock fails to get the lock and doesn't transfer the
+	 * PCC ownership to the platform, then one of the following will be TRUE
+	 *     1. There is at-least one CPU in Phase-I which will later execute
+	 * write_trylock, so the CPUs in Phase-I will be responsible for
+	 * executing the Phase-II.
+	 *     2. Some other CPU has beaten this CPU to successfully execute the
+	 * write_trylock and has already acquired the write_lock. We know for a
+	 * fact it(other CPU acquiring the write_lock) couldn't have happened
+	 * before this CPU's Phase-I as we held the read_lock.
+	 *     3. Some other CPU executing pcc CMD_READ has stolen the
+	 * down_write, in which case, send_pcc_cmd will check for pending
+	 * CMD_WRITE commands by checking the pending_pcc_write_cmd.
+	 * So this CPU can be certain that its request will be delivered
+	 *    So in all cases, this CPU knows that its request will be delivered
+	 * by another CPU and can return
+	 *
+	 * After getting the down_write we still need to check for
+	 * pending_pcc_write_cmd to take care of the following scenario
+	 *    The thread running this code could be scheduled out between
+	 * Phase-I and Phase-II. Before it is scheduled back on, another CPU
+	 * could have delivered the request to Platform by triggering the
+	 * doorbell and transferred the ownership of PCC to platform. So this
+	 * avoids triggering an unnecessary doorbell and more importantly before
+	 * triggering the doorbell it makes sure that the PCC channel ownership
+	 * is still with OSPM.
+	 *   pending_pcc_write_cmd can also be cleared by a different CPU, if
+	 * there was a pcc CMD_READ waiting on down_write and it steals the lock
+	 * before the pcc CMD_WRITE is completed. pcc_send_cmd checks for this
+	 * case during a CMD_READ and if there are pending writes it delivers
+	 * 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 */
+			/* 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 */
+		} 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);
+
+		/* send_pcc_cmd updates the status in case of failure */
+		ret = cpc_desc->write_cmd_status;
 	}
-busy_channel:
-	spin_unlock(&pcc_lock);
-
 	return ret;
 }
 EXPORT_SYMBOL_GPL(cppc_set_perf);
+
+/**
+ * cppc_get_transition_latency - returns frequency transition latency in ns
+ *
+ * ACPI CPPC does not explicitly specifiy how a platform can specify the
+ * transition latency for perfromance change requests. The closest we have
+ * is the timing information from the PCCT tables which provides the info
+ * on the number and frequency of PCC commands the platform can handle.
+ */
+unsigned int cppc_get_transition_latency(int cpu_num)
+{
+	/*
+	 * Expected transition latency is based on the PCCT timing values
+	 * Below are definition from ACPI spec:
+	 * pcc_nominal- Expected latency to process a command, in microseconds
+	 * pcc_mpar   - The maximum number of periodic requests that the subspace
+	 *              channel can support, reported in commands per minute. 0
+	 *              indicates no limitation.
+	 * pcc_mrtt   - The minimum amount of time that OSPM must wait after the
+	 *              completion of a command before issuing the next command,
+	 *              in microseconds.
+	 */
+	unsigned int latency_ns = 0;
+	struct cpc_desc *cpc_desc;
+	struct cpc_register_resource *desired_reg;
+
+	cpc_desc = per_cpu(cpc_desc_ptr, cpu_num);
+	if (!cpc_desc)
+		return CPUFREQ_ETERNAL;
+
+	desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
+	if (!CPC_IN_PCC(desired_reg))
+		return CPUFREQ_ETERNAL;
+
+	if (pcc_data.pcc_mpar)
+		latency_ns = 60 * (1000 * 1000 * 1000 / pcc_data.pcc_mpar);
+
+	latency_ns = max(latency_ns, pcc_data.pcc_nominal * 1000);
+	latency_ns = max(latency_ns, pcc_data.pcc_mrtt * 1000);
+
+	return latency_ns;
+}
+EXPORT_SYMBOL_GPL(cppc_get_transition_latency);

drivers/acpi/processor_driver.c

@@ -245,8 +245,8 @@ static int __acpi_processor_start(struct acpi_device *device)
 		return 0;
 
 	result = acpi_cppc_processor_probe(pr);
-	if (result)
-		return -ENODEV;
+	if (result && !IS_ENABLED(CONFIG_ACPI_CPU_FREQ_PSS))
+		dev_warn(&device->dev, "CPPC data invalid or not present\n");
 
 	if (!cpuidle_get_driver() || cpuidle_get_driver() == &acpi_idle_driver)
 		acpi_processor_power_init(pr);

drivers/cpufreq/cppc_cpufreq.c

@@ -30,13 +30,13 @@
  * performance capabilities, desired performance level
  * requested etc.
  */
-static struct cpudata **all_cpu_data;
+static struct cppc_cpudata **all_cpu_data;
 
 static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
 		unsigned int target_freq,
 		unsigned int relation)
 {
-	struct cpudata *cpu;
+	struct cppc_cpudata *cpu;
 	struct cpufreq_freqs freqs;
 	int ret = 0;
 
@@ -66,7 +66,7 @@ static int cppc_verify_policy(struct cpufreq_policy *policy)
 static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
 {
 	int cpu_num = policy->cpu;
-	struct cpudata *cpu = all_cpu_data[cpu_num];
+	struct cppc_cpudata *cpu = all_cpu_data[cpu_num];
 	int ret;
 
 	cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;
@@ -79,7 +79,7 @@ static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
 
 static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
 {
-	struct cpudata *cpu;
+	struct cppc_cpudata *cpu;
 	unsigned int cpu_num = policy->cpu;
 	int ret = 0;
 
@@ -98,6 +98,7 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
 	policy->max = cpu->perf_caps.highest_perf;
 	policy->cpuinfo.min_freq = policy->min;
 	policy->cpuinfo.max_freq = policy->max;
+	policy->cpuinfo.transition_latency = cppc_get_transition_latency(cpu_num);
 	policy->shared_type = cpu->shared_type;
 
 	if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
@@ -134,7 +135,7 @@ static struct cpufreq_driver cppc_cpufreq_driver = {
 static int __init cppc_cpufreq_init(void)
 {
 	int i, ret = 0;
-	struct cpudata *cpu;
+	struct cppc_cpudata *cpu;
 
 	if (acpi_disabled)
 		return -ENODEV;
@@ -144,7 +145,7 @@ static int __init cppc_cpufreq_init(void)
 		return -ENOMEM;
 
 	for_each_possible_cpu(i) {
-		all_cpu_data[i] = kzalloc(sizeof(struct cpudata), GFP_KERNEL);
+		all_cpu_data[i] = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL);
 		if (!all_cpu_data[i])
 			goto out;
 
@@ -175,7 +176,7 @@ out:
 
 static void __exit cppc_cpufreq_exit(void)
 {
-	struct cpudata *cpu;
+	struct cppc_cpudata *cpu;
 	int i;
 
 	cpufreq_unregister_driver(&cppc_cpufreq_driver);

drivers/mailbox/pcc.c

@@ -59,6 +59,7 @@
 #include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/init.h>
+#include <linux/interrupt.h>
 #include <linux/list.h>
 #include <linux/platform_device.h>
 #include <linux/mailbox_controller.h>
@@ -68,11 +69,16 @@
 #include "mailbox.h"
 
 #define MAX_PCC_SUBSPACES	256
+#define MBOX_IRQ_NAME		"pcc-mbox"
 
 static struct mbox_chan *pcc_mbox_channels;
 
 /* Array of cached virtual address for doorbell registers */
 static void __iomem **pcc_doorbell_vaddr;
+/* Array of cached virtual address for doorbell ack registers */
+static void __iomem **pcc_doorbell_ack_vaddr;
+/* Array of doorbell interrupts */
+static int *pcc_doorbell_irq;
 
 static struct mbox_controller pcc_mbox_ctrl = {};
 /**
@@ -91,6 +97,132 @@ static struct mbox_chan *get_pcc_channel(int id)
 	return &pcc_mbox_channels[id];
 }
 
+/*
+ * PCC can be used with perf critical drivers such as CPPC
+ * So it makes sense to locally cache the virtual address and
+ * use it to read/write to PCC registers such as doorbell register
+ *
+ * The below read_register and write_registers are used to read and
+ * write from perf critical registers such as PCC doorbell register
+ */
+static int read_register(void __iomem *vaddr, u64 *val, unsigned int bit_width)
+{
+	int ret_val = 0;
+
+	switch (bit_width) {
+	case 8:
+		*val = readb(vaddr);
+		break;
+	case 16:
+		*val = readw(vaddr);
+		break;
+	case 32:
+		*val = readl(vaddr);
+		break;
+	case 64:
+		*val = readq(vaddr);
+		break;
+	default:
+		pr_debug("Error: Cannot read register of %u bit width",
+			bit_width);
+		ret_val = -EFAULT;
+		break;
+	}
+	return ret_val;
+}
+
+static int write_register(void __iomem *vaddr, u64 val, unsigned int bit_width)
+{
+	int ret_val = 0;
+
+	switch (bit_width) {
+	case 8:
+		writeb(val, vaddr);
+		break;
+	case 16:
+		writew(val, vaddr);
+		break;
+	case 32:
+		writel(val, vaddr);
+		break;
+	case 64:
+		writeq(val, vaddr);
+		break;
+	default:
+		pr_debug("Error: Cannot write register of %u bit width",
+			bit_width);
+		ret_val = -EFAULT;
+		break;
+	}
+	return ret_val;
+}
+
+/**
+ * pcc_map_interrupt - Map a PCC subspace GSI to a linux IRQ number
+ * @interrupt: GSI number.
+ * @flags: interrupt flags
+ *
+ * Returns: a valid linux IRQ number on success
+ *		0 or -EINVAL on failure
+ */
+static int pcc_map_interrupt(u32 interrupt, u32 flags)
+{
+	int trigger, polarity;
+
+	if (!interrupt)
+		return 0;
+
+	trigger = (flags & ACPI_PCCT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
+			: ACPI_LEVEL_SENSITIVE;
+
+	polarity = (flags & ACPI_PCCT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
+			: ACPI_ACTIVE_HIGH;
+
+	return acpi_register_gsi(NULL, interrupt, trigger, polarity);
+}
+
+/**
+ * pcc_mbox_irq - PCC mailbox interrupt handler
+ */
+static irqreturn_t pcc_mbox_irq(int irq, void *p)
+{
+	struct acpi_generic_address *doorbell_ack;
+	struct acpi_pcct_hw_reduced *pcct_ss;
+	struct mbox_chan *chan = p;
+	u64 doorbell_ack_preserve;
+	u64 doorbell_ack_write;
+	u64 doorbell_ack_val;
+	int ret;
+
+	pcct_ss = chan->con_priv;
+
+	mbox_chan_received_data(chan, NULL);
+
+	if (pcct_ss->header.type == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
+		struct acpi_pcct_hw_reduced_type2 *pcct2_ss = chan->con_priv;
+		u32 id = chan - pcc_mbox_channels;
+
+		doorbell_ack = &pcct2_ss->doorbell_ack_register;
+		doorbell_ack_preserve = pcct2_ss->ack_preserve_mask;
+		doorbell_ack_write = pcct2_ss->ack_write_mask;
+
+		ret = read_register(pcc_doorbell_ack_vaddr[id],
+				    &doorbell_ack_val,
+				    doorbell_ack->bit_width);
+		if (ret)
+			return IRQ_NONE;
+
+		ret = write_register(pcc_doorbell_ack_vaddr[id],
+				     (doorbell_ack_val & doorbell_ack_preserve)
+					| doorbell_ack_write,
+				     doorbell_ack->bit_width);
+		if (ret)
+			return IRQ_NONE;
+	}
+
+	return IRQ_HANDLED;
+}
+
 /**
  * pcc_mbox_request_channel - PCC clients call this function to
  *		request a pointer to their PCC subspace, from which they
@@ -135,6 +267,18 @@ struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
 	if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
 		chan->txdone_method |= TXDONE_BY_ACK;
 
+	if (pcc_doorbell_irq[subspace_id] > 0) {
+		int rc;
+
+		rc = devm_request_irq(dev, pcc_doorbell_irq[subspace_id],
+				      pcc_mbox_irq, 0, MBOX_IRQ_NAME, chan);
+		if (unlikely(rc)) {
+			dev_err(dev, "failed to register PCC interrupt %d\n",
+				pcc_doorbell_irq[subspace_id]);
+			chan = ERR_PTR(rc);
+		}
+	}
+
 	spin_unlock_irqrestore(&chan->lock, flags);
 
 	return chan;
@@ -149,80 +293,30 @@ EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
  */
 void pcc_mbox_free_channel(struct mbox_chan *chan)
 {
+	u32 id = chan - pcc_mbox_channels;
 	unsigned long flags;
 
 	if (!chan || !chan->cl)
 		return;
 
+	if (id >= pcc_mbox_ctrl.num_chans) {
+		pr_debug("pcc_mbox_free_channel: Invalid mbox_chan passed\n");
+		return;
+	}
+
 	spin_lock_irqsave(&chan->lock, flags);
 	chan->cl = NULL;
 	chan->active_req = NULL;
 	if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
 		chan->txdone_method = TXDONE_BY_POLL;
 
+	if (pcc_doorbell_irq[id] > 0)
+		devm_free_irq(chan->mbox->dev, pcc_doorbell_irq[id], chan);
+
 	spin_unlock_irqrestore(&chan->lock, flags);
 }
 EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
 
-/*
- * PCC can be used with perf critical drivers such as CPPC
- * So it makes sense to locally cache the virtual address and
- * use it to read/write to PCC registers such as doorbell register
- *
- * The below read_register and write_registers are used to read and
- * write from perf critical registers such as PCC doorbell register
- */
-static int read_register(void __iomem *vaddr, u64 *val, unsigned int bit_width)
-{
-	int ret_val = 0;
-
-	switch (bit_width) {
-	case 8:
-		*val = readb(vaddr);
-		break;
-	case 16:
-		*val = readw(vaddr);
-		break;
-	case 32:
-		*val = readl(vaddr);
-		break;
-	case 64:
-		*val = readq(vaddr);
-		break;
-	default:
-		pr_debug("Error: Cannot read register of %u bit width",
-			bit_width);
-		ret_val = -EFAULT;
-		break;
-	}
-	return ret_val;
-}
-
-static int write_register(void __iomem *vaddr, u64 val, unsigned int bit_width)
-{
-	int ret_val = 0;
-
-	switch (bit_width) {
-	case 8:
-		writeb(val, vaddr);
-		break;
-	case 16:
-		writew(val, vaddr);
-		break;
-	case 32:
-		writel(val, vaddr);
-		break;
-	case 64:
-		writeq(val, vaddr);
-		break;
-	default:
-		pr_debug("Error: Cannot write register of %u bit width",
-			bit_width);
-		ret_val = -EFAULT;
-		break;
-	}
-	return ret_val;
-}
 
 /**
  * pcc_send_data - Called from Mailbox Controller code. Used
@@ -296,8 +390,10 @@ static int parse_pcc_subspace(struct acpi_subtable_header *header,
 	if (pcc_mbox_ctrl.num_chans <= MAX_PCC_SUBSPACES) {
 		pcct_ss = (struct acpi_pcct_hw_reduced *) header;
 
-		if (pcct_ss->header.type !=
-				ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE) {
+		if ((pcct_ss->header.type !=
+				ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE)
+		    && (pcct_ss->header.type !=
+				ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2)) {
 			pr_err("Incorrect PCC Subspace type detected\n");
 			return -EINVAL;
 		}
@@ -306,6 +402,43 @@ static int parse_pcc_subspace(struct acpi_subtable_header *header,
 	return 0;
 }
 
+/**
+ * pcc_parse_subspace_irq - Parse the PCC IRQ and PCC ACK register
+ *		There should be one entry per PCC client.
+ * @id: PCC subspace index.
+ * @pcct_ss: Pointer to the ACPI subtable header under the PCCT.
+ *
+ * Return: 0 for Success, else errno.
+ *
+ * This gets called for each entry in the PCC table.
+ */
+static int pcc_parse_subspace_irq(int id,
+				  struct acpi_pcct_hw_reduced *pcct_ss)
+{
+	pcc_doorbell_irq[id] = pcc_map_interrupt(pcct_ss->doorbell_interrupt,
+						 (u32)pcct_ss->flags);
+	if (pcc_doorbell_irq[id] <= 0) {
+		pr_err("PCC GSI %d not registered\n",
+		       pcct_ss->doorbell_interrupt);
+		return -EINVAL;
+	}
+
+	if (pcct_ss->header.type
+		== ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
+		struct acpi_pcct_hw_reduced_type2 *pcct2_ss = (void *)pcct_ss;
+
+		pcc_doorbell_ack_vaddr[id] = acpi_os_ioremap(
+				pcct2_ss->doorbell_ack_register.address,
+				pcct2_ss->doorbell_ack_register.bit_width / 8);
+		if (!pcc_doorbell_ack_vaddr[id]) {
+			pr_err("Failed to ioremap PCC ACK register\n");
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+
 /**
  * acpi_pcc_probe - Parse the ACPI tree for the PCCT.
  *
@@ -316,7 +449,9 @@ static int __init acpi_pcc_probe(void)
 	acpi_size pcct_tbl_header_size;
 	struct acpi_table_header *pcct_tbl;
 	struct acpi_subtable_header *pcct_entry;
-	int count, i;
+	struct acpi_table_pcct *acpi_pcct_tbl;
+	int count, i, rc;
+	int sum = 0;
 	acpi_status status = AE_OK;
 
 	/* Search for PCCT */
@@ -333,37 +468,66 @@ static int __init acpi_pcc_probe(void)
 			sizeof(struct acpi_table_pcct),
 			ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE,
 			parse_pcc_subspace, MAX_PCC_SUBSPACES);
+	sum += (count > 0) ? count : 0;
+
+	count = acpi_table_parse_entries(ACPI_SIG_PCCT,
+			sizeof(struct acpi_table_pcct),
+			ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2,
+			parse_pcc_subspace, MAX_PCC_SUBSPACES);
+	sum += (count > 0) ? count : 0;
 
-	if (count <= 0) {
+	if (sum == 0 || sum >= MAX_PCC_SUBSPACES) {
 		pr_err("Error parsing PCC subspaces from PCCT\n");
 		return -EINVAL;
 	}
 
 	pcc_mbox_channels = kzalloc(sizeof(struct mbox_chan) *
-			count, GFP_KERNEL);
-
+			sum, GFP_KERNEL);
 	if (!pcc_mbox_channels) {
 		pr_err("Could not allocate space for PCC mbox channels\n");
 		return -ENOMEM;
 	}
 
-	pcc_doorbell_vaddr = kcalloc(count, sizeof(void *), GFP_KERNEL);
+	pcc_doorbell_vaddr = kcalloc(sum, sizeof(void *), GFP_KERNEL);
 	if (!pcc_doorbell_vaddr) {
-		kfree(pcc_mbox_channels);
-		return -ENOMEM;
+		rc = -ENOMEM;
+		goto err_free_mbox;
+	}
+
+	pcc_doorbell_ack_vaddr = kcalloc(sum, sizeof(void *), GFP_KERNEL);
+	if (!pcc_doorbell_ack_vaddr) {
+		rc = -ENOMEM;
+		goto err_free_db_vaddr;
+	}
+
+	pcc_doorbell_irq = kcalloc(sum, sizeof(int), GFP_KERNEL);
+	if (!pcc_doorbell_irq) {
+		rc = -ENOMEM;
+		goto err_free_db_ack_vaddr;
 	}
 
 	/* Point to the first PCC subspace entry */
 	pcct_entry = (struct acpi_subtable_header *) (
 		(unsigned long) pcct_tbl + sizeof(struct acpi_table_pcct));
 
-	for (i = 0; i < count; i++) {
+	acpi_pcct_tbl = (struct acpi_table_pcct *) pcct_tbl;
+	if (acpi_pcct_tbl->flags & ACPI_PCCT_DOORBELL)
+		pcc_mbox_ctrl.txdone_irq = true;
+
+	for (i = 0; i < sum; i++) {
 		struct acpi_generic_address *db_reg;
 		struct acpi_pcct_hw_reduced *pcct_ss;
 		pcc_mbox_channels[i].con_priv = pcct_entry;
 
+		pcct_ss = (struct acpi_pcct_hw_reduced *) pcct_entry;
+
+		if (pcc_mbox_ctrl.txdone_irq) {
+			rc = pcc_parse_subspace_irq(i, pcct_ss);
+			if (rc < 0)
+				goto err;
+		}
+
 		/* If doorbell is in system memory cache the virt address */
-		pcct_ss = (struct acpi_pcct_hw_reduced *)pcct_entry;
 		db_reg = &pcct_ss->doorbell_register;
 		if (db_reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
 			pcc_doorbell_vaddr[i] = acpi_os_ioremap(db_reg->address,
@@ -372,11 +536,21 @@ static int __init acpi_pcc_probe(void)
 			((unsigned long) pcct_entry + pcct_entry->length);
 	}
 
-	pcc_mbox_ctrl.num_chans = count;
+	pcc_mbox_ctrl.num_chans = sum;
 
 	pr_info("Detected %d PCC Subspaces\n", pcc_mbox_ctrl.num_chans);
 
 	return 0;
+
+err:
+	kfree(pcc_doorbell_irq);
+err_free_db_ack_vaddr:
+	kfree(pcc_doorbell_ack_vaddr);
+err_free_db_vaddr:
+	kfree(pcc_doorbell_vaddr);
+err_free_mbox:
+	kfree(pcc_mbox_channels);
+	return rc;
 }
 
 /**

include/acpi/cppc_acpi.h

@@ -24,7 +24,9 @@
 #define CPPC_NUM_ENT	21
 #define CPPC_REV	2
 
-#define PCC_CMD_COMPLETE 1
+#define PCC_CMD_COMPLETE_MASK	(1 << 0)
+#define PCC_ERROR_MASK		(1 << 2)
+
 #define MAX_CPC_REG_ENT 19
 
 /* CPPC specific PCC commands. */
@@ -49,6 +51,7 @@ struct cpc_reg {
  */
 struct cpc_register_resource {
 	acpi_object_type type;
+	u64 __iomem *sys_mem_vaddr;
 	union {
 		struct cpc_reg reg;
 		u64 int_value;
@@ -60,8 +63,11 @@ struct cpc_desc {
 	int num_entries;
 	int version;
 	int cpu_id;
+	int write_cmd_status;
+	int write_cmd_id;
 	struct cpc_register_resource cpc_regs[MAX_CPC_REG_ENT];
 	struct acpi_psd_package domain_info;
+	struct kobject kobj;
 };
 
 /* These are indexes into the per-cpu cpc_regs[]. Order is important. */
@@ -96,7 +102,6 @@ enum cppc_regs {
 struct cppc_perf_caps {
 	u32 highest_perf;
 	u32 nominal_perf;
-	u32 reference_perf;
 	u32 lowest_perf;
 };
 
@@ -108,13 +113,13 @@ struct cppc_perf_ctrls {
 
 struct cppc_perf_fb_ctrs {
 	u64 reference;
-	u64 prev_reference;
 	u64 delivered;
-	u64 prev_delivered;
+	u64 reference_perf;
+	u64 ctr_wrap_time;
 };
 
 /* Per CPU container for runtime CPPC management. */
-struct cpudata {
+struct cppc_cpudata {
 	int cpu;
 	struct cppc_perf_caps perf_caps;
 	struct cppc_perf_ctrls perf_ctrls;
@@ -127,6 +132,7 @@ struct cpudata {
 extern int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs);
 extern int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);
 extern int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps);
-extern int acpi_get_psd_map(struct cpudata **);
+extern int acpi_get_psd_map(struct cppc_cpudata **);
+extern unsigned int cppc_get_transition_latency(int cpu);
 
 #endif /* _CPPC_ACPI_H*/