--- /dev/null
+/*
+ * pcc-cpufreq.txt - PCC interface documentation
+ *
+ * Copyright (C) 2009 Red Hat, Matthew Garrett <mjg@redhat.com>
+ * Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
+ * Nagananda Chumbalkar <nagananda.chumbalkar@hp.com>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or NON
+ * INFRINGEMENT. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+
+ Processor Clocking Control Driver
+ ---------------------------------
+
+Contents:
+---------
+1. Introduction
+1.1 PCC interface
+1.1.1 Get Average Frequency
+1.1.2 Set Desired Frequency
+1.2 Platforms affected
+2. Driver and /sys details
+2.1 scaling_available_frequencies
+2.2 cpuinfo_transition_latency
+2.3 cpuinfo_cur_freq
+2.4 related_cpus
+3. Caveats
+
+1. Introduction:
+----------------
+Processor Clocking Control (PCC) is an interface between the platform
+firmware and OSPM. It is a mechanism for coordinating processor
+performance (ie: frequency) between the platform firmware and the OS.
+
+The PCC driver (pcc-cpufreq) allows OSPM to take advantage of the PCC
+interface.
+
+OS utilizes the PCC interface to inform platform firmware what frequency the
+OS wants for a logical processor. The platform firmware attempts to achieve
+the requested frequency. If the request for the target frequency could not be
+satisfied by platform firmware, then it usually means that power budget
+conditions are in place, and "power capping" is taking place.
+
+1.1 PCC interface:
+------------------
+The complete PCC specification is available here:
+http://www.acpica.org/download/Processor-Clocking-Control-v1p0.pdf
+
+PCC relies on a shared memory region that provides a channel for communication
+between the OS and platform firmware. PCC also implements a "doorbell" that
+is used by the OS to inform the platform firmware that a command has been
+sent.
+
+The ACPI PCCH() method is used to discover the location of the PCC shared
+memory region. The shared memory region header contains the "command" and
+"status" interface. PCCH() also contains details on how to access the platform
+doorbell.
+
+The following commands are supported by the PCC interface:
+* Get Average Frequency
+* Set Desired Frequency
+
+The ACPI PCCP() method is implemented for each logical processor and is
+used to discover the offsets for the input and output buffers in the shared
+memory region.
+
+When PCC mode is enabled, the platform will not expose processor performance
+or throttle states (_PSS, _TSS and related ACPI objects) to OSPM. Therefore,
+the native P-state driver (such as acpi-cpufreq for Intel, powernow-k8 for
+AMD) will not load.
+
+However, OSPM remains in control of policy. The governor (eg: "ondemand")
+computes the required performance for each processor based on server workload.
+The PCC driver fills in the command interface, and the input buffer and
+communicates the request to the platform firmware. The platform firmware is
+responsible for delivering the requested performance.
+
+Each PCC command is "global" in scope and can affect all the logical CPUs in
+the system. Therefore, PCC is capable of performing "group" updates. With PCC
+the OS is capable of getting/setting the frequency of all the logical CPUs in
+the system with a single call to the BIOS.
+
+1.1.1 Get Average Frequency:
+----------------------------
+This command is used by the OSPM to query the running frequency of the
+processor since the last time this command was completed. The output buffer
+indicates the average unhalted frequency of the logical processor expressed as
+a percentage of the nominal (ie: maximum) CPU frequency. The output buffer
+also signifies if the CPU frequency is limited by a power budget condition.
+
+1.1.2 Set Desired Frequency:
+----------------------------
+This command is used by the OSPM to communicate to the platform firmware the
+desired frequency for a logical processor. The output buffer is currently
+ignored by OSPM. The next invocation of "Get Average Frequency" will inform
+OSPM if the desired frequency was achieved or not.
+
+1.2 Platforms affected:
+-----------------------
+The PCC driver will load on any system where the platform firmware:
+* supports the PCC interface, and the associated PCCH() and PCCP() methods
+* assumes responsibility for managing the hardware clocking controls in order
+to deliver the requested processor performance
+
+Currently, certain HP ProLiant platforms implement the PCC interface. On those
+platforms PCC is the "default" choice.
+
+However, it is possible to disable this interface via a BIOS setting. In
+such an instance, as is also the case on platforms where the PCC interface
+is not implemented, the PCC driver will fail to load silently.
+
+2. Driver and /sys details:
+---------------------------
+When the driver loads, it merely prints the lowest and the highest CPU
+frequencies supported by the platform firmware.
+
+The PCC driver loads with a message such as:
+pcc-cpufreq: (v1.00.00) driver loaded with frequency limits: 1600 MHz, 2933
+MHz
+
+This means that the OPSM can request the CPU to run at any frequency in
+between the limits (1600 MHz, and 2933 MHz) specified in the message.
+
+Internally, there is no need for the driver to convert the "target" frequency
+to a corresponding P-state.
+
+The VERSION number for the driver will be of the format v.xy.ab.
+eg: 1.00.02
+ ----- --
+ | |
+ | -- this will increase with bug fixes/enhancements to the driver
+ |-- this is the version of the PCC specification the driver adheres to
+
+
+The following is a brief discussion on some of the fields exported via the
+/sys filesystem and how their values are affected by the PCC driver:
+
+2.1 scaling_available_frequencies:
+----------------------------------
+scaling_available_frequencies is not created in /sys. No intermediate
+frequencies need to be listed because the BIOS will try to achieve any
+frequency, within limits, requested by the governor. A frequency does not have
+to be strictly associated with a P-state.
+
+2.2 cpuinfo_transition_latency:
+-------------------------------
+The cpuinfo_transition_latency field is 0. The PCC specification does
+not include a field to expose this value currently.
+
+2.3 cpuinfo_cur_freq:
+---------------------
+A) Often cpuinfo_cur_freq will show a value different than what is declared
+in the scaling_available_frequencies or scaling_cur_freq, or scaling_max_freq.
+This is due to "turbo boost" available on recent Intel processors. If certain
+conditions are met the BIOS can achieve a slightly higher speed than requested
+by OSPM. An example:
+
+scaling_cur_freq : 2933000
+cpuinfo_cur_freq : 3196000
+
+B) There is a round-off error associated with the cpuinfo_cur_freq value.
+Since the driver obtains the current frequency as a "percentage" (%) of the
+nominal frequency from the BIOS, sometimes, the values displayed by
+scaling_cur_freq and cpuinfo_cur_freq may not match. An example:
+
+scaling_cur_freq : 1600000
+cpuinfo_cur_freq : 1583000
+
+In this example, the nominal frequency is 2933 MHz. The driver obtains the
+current frequency, cpuinfo_cur_freq, as 54% of the nominal frequency:
+
+ 54% of 2933 MHz = 1583 MHz
+
+Nominal frequency is the maximum frequency of the processor, and it usually
+corresponds to the frequency of the P0 P-state.
+
+2.4 related_cpus:
+-----------------
+The related_cpus field is identical to affected_cpus.
+
+affected_cpus : 4
+related_cpus : 4
+
+Currently, the PCC driver does not evaluate _PSD. The platforms that support
+PCC do not implement SW_ALL. So OSPM doesn't need to perform any coordination
+to ensure that the same frequency is requested of all dependent CPUs.
+
+3. Caveats:
+-----------
+The "cpufreq_stats" module in its present form cannot be loaded and
+expected to work with the PCC driver. Since the "cpufreq_stats" module
+provides information wrt each P-state, it is not applicable to the PCC driver.
--- /dev/null
+/*
+ * pcc-cpufreq.c - Processor Clocking Control firmware cpufreq interface
+ *
+ * Copyright (C) 2009 Red Hat, Matthew Garrett <mjg@redhat.com>
+ * Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
+ * Nagananda Chumbalkar <nagananda.chumbalkar@hp.com>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or NON
+ * INFRINGEMENT. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/sched.h>
+#include <linux/cpufreq.h>
+#include <linux/compiler.h>
+
+#include <linux/acpi.h>
+#include <linux/io.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+
+#include <acpi/processor.h>
+
+#define PCC_VERSION "1.00.00"
+#define POLL_LOOPS 300
+
+#define CMD_COMPLETE 0x1
+#define CMD_GET_FREQ 0x0
+#define CMD_SET_FREQ 0x1
+
+#define BUF_SZ 4
+
+#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, \
+ "pcc-cpufreq", msg)
+
+struct pcc_register_resource {
+ u8 descriptor;
+ u16 length;
+ u8 space_id;
+ u8 bit_width;
+ u8 bit_offset;
+ u8 access_size;
+ u64 address;
+} __attribute__ ((packed));
+
+struct pcc_memory_resource {
+ u8 descriptor;
+ u16 length;
+ u8 space_id;
+ u8 resource_usage;
+ u8 type_specific;
+ u64 granularity;
+ u64 minimum;
+ u64 maximum;
+ u64 translation_offset;
+ u64 address_length;
+} __attribute__ ((packed));
+
+static struct cpufreq_driver pcc_cpufreq_driver;
+
+struct pcc_header {
+ u32 signature;
+ u16 length;
+ u8 major;
+ u8 minor;
+ u32 features;
+ u16 command;
+ u16 status;
+ u32 latency;
+ u32 minimum_time;
+ u32 maximum_time;
+ u32 nominal;
+ u32 throttled_frequency;
+ u32 minimum_frequency;
+};
+
+static void __iomem *pcch_virt_addr;
+static struct pcc_header __iomem *pcch_hdr;
+
+static DEFINE_SPINLOCK(pcc_lock);
+
+static struct acpi_generic_address doorbell;
+
+static u64 doorbell_preserve;
+static u64 doorbell_write;
+
+static u8 OSC_UUID[16] = {0x63, 0x9B, 0x2C, 0x9F, 0x70, 0x91, 0x49, 0x1f,
+ 0xBB, 0x4F, 0xA5, 0x98, 0x2F, 0xA1, 0xB5, 0x46};
+
+struct pcc_cpu {
+ u32 input_offset;
+ u32 output_offset;
+};
+
+static struct pcc_cpu *pcc_cpu_info;
+
+static int pcc_cpufreq_verify(struct cpufreq_policy *policy)
+{
+ cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
+ policy->cpuinfo.max_freq);
+ return 0;
+}
+
+static inline void pcc_cmd(void)
+{
+ u64 doorbell_value;
+ int i;
+
+ acpi_read(&doorbell_value, &doorbell);
+ acpi_write((doorbell_value & doorbell_preserve) | doorbell_write,
+ &doorbell);
+
+ for (i = 0; i < POLL_LOOPS; i++) {
+ if (ioread16(&pcch_hdr->status) & CMD_COMPLETE)
+ break;
+ }
+}
+
+static inline void pcc_clear_mapping(void)
+{
+ if (pcch_virt_addr)
+ iounmap(pcch_virt_addr);
+ pcch_virt_addr = NULL;
+}
+
+static unsigned int pcc_get_freq(unsigned int cpu)
+{
+ struct pcc_cpu *pcc_cpu_data;
+ unsigned int curr_freq;
+ unsigned int freq_limit;
+ u16 status;
+ u32 input_buffer;
+ u32 output_buffer;
+
+ spin_lock(&pcc_lock);
+
+ dprintk("get: get_freq for CPU %d\n", cpu);
+ pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
+
+ input_buffer = 0x1;
+ iowrite32(input_buffer,
+ (pcch_virt_addr + pcc_cpu_data->input_offset));
+ iowrite16(CMD_GET_FREQ, &pcch_hdr->command);
+
+ pcc_cmd();
+
+ output_buffer =
+ ioread32(pcch_virt_addr + pcc_cpu_data->output_offset);
+
+ /* Clear the input buffer - we are done with the current command */
+ memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
+
+ status = ioread16(&pcch_hdr->status);
+ if (status != CMD_COMPLETE) {
+ dprintk("get: FAILED: for CPU %d, status is %d\n",
+ cpu, status);
+ goto cmd_incomplete;
+ }
+ iowrite16(0, &pcch_hdr->status);
+ curr_freq = (((ioread32(&pcch_hdr->nominal) * (output_buffer & 0xff))
+ / 100) * 1000);
+
+ dprintk("get: SUCCESS: (virtual) output_offset for cpu %d is "
+ "0x%x, contains a value of: 0x%x. Speed is: %d MHz\n",
+ cpu, (pcch_virt_addr + pcc_cpu_data->output_offset),
+ output_buffer, curr_freq);
+
+ freq_limit = (output_buffer >> 8) & 0xff;
+ if (freq_limit != 0xff) {
+ dprintk("get: frequency for cpu %d is being temporarily"
+ " capped at %d\n", cpu, curr_freq);
+ }
+
+ spin_unlock(&pcc_lock);
+ return curr_freq;
+
+cmd_incomplete:
+ iowrite16(0, &pcch_hdr->status);
+ spin_unlock(&pcc_lock);
+ return -EINVAL;
+}
+
+static int pcc_cpufreq_target(struct cpufreq_policy *policy,
+ unsigned int target_freq,
+ unsigned int relation)
+{
+ struct pcc_cpu *pcc_cpu_data;
+ struct cpufreq_freqs freqs;
+ u16 status;
+ u32 input_buffer;
+ int cpu;
+
+ spin_lock(&pcc_lock);
+ cpu = policy->cpu;
+ pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
+
+ dprintk("target: CPU %d should go to target freq: %d "
+ "(virtual) input_offset is 0x%x\n",
+ cpu, target_freq,
+ (pcch_virt_addr + pcc_cpu_data->input_offset));
+
+ freqs.new = target_freq;
+ freqs.cpu = cpu;
+ cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+ input_buffer = 0x1 | (((target_freq * 100)
+ / (ioread32(&pcch_hdr->nominal) * 1000)) << 8);
+ iowrite32(input_buffer,
+ (pcch_virt_addr + pcc_cpu_data->input_offset));
+ iowrite16(CMD_SET_FREQ, &pcch_hdr->command);
+
+ pcc_cmd();
+
+ /* Clear the input buffer - we are done with the current command */
+ memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
+
+ status = ioread16(&pcch_hdr->status);
+ if (status != CMD_COMPLETE) {
+ dprintk("target: FAILED for cpu %d, with status: 0x%x\n",
+ cpu, status);
+ goto cmd_incomplete;
+ }
+ iowrite16(0, &pcch_hdr->status);
+
+ cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+ dprintk("target: was SUCCESSFUL for cpu %d\n", cpu);
+ spin_unlock(&pcc_lock);
+
+ return 0;
+
+cmd_incomplete:
+ iowrite16(0, &pcch_hdr->status);
+ spin_unlock(&pcc_lock);
+ return -EINVAL;
+}
+
+static int pcc_get_offset(int cpu)
+{
+ acpi_status status;
+ struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
+ union acpi_object *pccp, *offset;
+ struct pcc_cpu *pcc_cpu_data;
+ struct acpi_processor *pr;
+ int ret = 0;
+
+ pr = per_cpu(processors, cpu);
+ pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
+
+ status = acpi_evaluate_object(pr->handle, "PCCP", NULL, &buffer);
+ if (ACPI_FAILURE(status))
+ return -ENODEV;
+
+ pccp = buffer.pointer;
+ if (!pccp || pccp->type != ACPI_TYPE_PACKAGE) {
+ ret = -ENODEV;
+ goto out_free;
+ };
+
+ offset = &(pccp->package.elements[0]);
+ if (!offset || offset->type != ACPI_TYPE_INTEGER) {
+ ret = -ENODEV;
+ goto out_free;
+ }
+
+ pcc_cpu_data->input_offset = offset->integer.value;
+
+ offset = &(pccp->package.elements[1]);
+ if (!offset || offset->type != ACPI_TYPE_INTEGER) {
+ ret = -ENODEV;
+ goto out_free;
+ }
+
+ pcc_cpu_data->output_offset = offset->integer.value;
+
+ memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
+ memset_io((pcch_virt_addr + pcc_cpu_data->output_offset), 0, BUF_SZ);
+
+ dprintk("pcc_get_offset: for CPU %d: pcc_cpu_data "
+ "input_offset: 0x%x, pcc_cpu_data output_offset: 0x%x\n",
+ cpu, pcc_cpu_data->input_offset, pcc_cpu_data->output_offset);
+out_free:
+ kfree(buffer.pointer);
+ return ret;
+}
+
+static int __init pcc_cpufreq_do_osc(acpi_handle *handle)
+{
+ acpi_status status;
+ struct acpi_object_list input;
+ struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
+ union acpi_object in_params[4];
+ union acpi_object *out_obj;
+ u32 capabilities[2];
+ u32 errors;
+ u32 supported;
+ int ret = 0;
+
+ input.count = 4;
+ input.pointer = in_params;
+ input.count = 4;
+ input.pointer = in_params;
+ in_params[0].type = ACPI_TYPE_BUFFER;
+ in_params[0].buffer.length = 16;
+ in_params[0].buffer.pointer = OSC_UUID;
+ in_params[1].type = ACPI_TYPE_INTEGER;
+ in_params[1].integer.value = 1;
+ in_params[2].type = ACPI_TYPE_INTEGER;
+ in_params[2].integer.value = 2;
+ in_params[3].type = ACPI_TYPE_BUFFER;
+ in_params[3].buffer.length = 8;
+ in_params[3].buffer.pointer = (u8 *)&capabilities;
+
+ capabilities[0] = OSC_QUERY_ENABLE;
+ capabilities[1] = 0x1;
+
+ status = acpi_evaluate_object(*handle, "_OSC", &input, &output);
+ if (ACPI_FAILURE(status))
+ return -ENODEV;
+
+ if (!output.length)
+ return -ENODEV;
+
+ out_obj = output.pointer;
+ if (out_obj->type != ACPI_TYPE_BUFFER) {
+ ret = -ENODEV;
+ goto out_free;
+ }
+
+ errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
+ if (errors) {
+ ret = -ENODEV;
+ goto out_free;
+ }
+
+ supported = *((u32 *)(out_obj->buffer.pointer + 4));
+ if (!(supported & 0x1)) {
+ ret = -ENODEV;
+ goto out_free;
+ }
+
+ kfree(output.pointer);
+ capabilities[0] = 0x0;
+ capabilities[1] = 0x1;
+
+ status = acpi_evaluate_object(*handle, "_OSC", &input, &output);
+ if (ACPI_FAILURE(status))
+ return -ENODEV;
+
+ if (!output.length)
+ return -ENODEV;
+
+ out_obj = output.pointer;
+ if (out_obj->type != ACPI_TYPE_BUFFER) {
+ ret = -ENODEV;
+ goto out_free;
+ }
+
+ errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
+ if (errors) {
+ ret = -ENODEV;
+ goto out_free;
+ }
+
+ supported = *((u32 *)(out_obj->buffer.pointer + 4));
+ if (!(supported & 0x1)) {
+ ret = -ENODEV;
+ goto out_free;
+ }
+
+out_free:
+ kfree(output.pointer);
+ return ret;
+}
+
+static int __init pcc_cpufreq_probe(void)
+{
+ acpi_status status;
+ struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
+ struct pcc_memory_resource *mem_resource;
+ struct pcc_register_resource *reg_resource;
+ union acpi_object *out_obj, *member;
+ acpi_handle handle, osc_handle;
+ int ret = 0;
+
+ status = acpi_get_handle(NULL, "\\_SB", &handle);
+ if (ACPI_FAILURE(status))
+ return -ENODEV;
+
+ status = acpi_get_handle(handle, "_OSC", &osc_handle);
+ if (ACPI_SUCCESS(status)) {
+ ret = pcc_cpufreq_do_osc(&osc_handle);
+ if (ret)
+ dprintk("probe: _OSC evaluation did not succeed\n");
+ /* Firmware's use of _OSC is optional */
+ ret = 0;
+ }
+
+ status = acpi_evaluate_object(handle, "PCCH", NULL, &output);
+ if (ACPI_FAILURE(status))
+ return -ENODEV;
+
+ out_obj = output.pointer;
+ if (out_obj->type != ACPI_TYPE_PACKAGE) {
+ ret = -ENODEV;
+ goto out_free;
+ }
+
+ member = &out_obj->package.elements[0];
+ if (member->type != ACPI_TYPE_BUFFER) {
+ ret = -ENODEV;
+ goto out_free;
+ }
+
+ mem_resource = (struct pcc_memory_resource *)member->buffer.pointer;
+
+ dprintk("probe: mem_resource descriptor: 0x%x,"
+ " length: %d, space_id: %d, resource_usage: %d,"
+ " type_specific: %d, granularity: 0x%llx,"
+ " minimum: 0x%llx, maximum: 0x%llx,"
+ " translation_offset: 0x%llx, address_length: 0x%llx\n",
+ mem_resource->descriptor, mem_resource->length,
+ mem_resource->space_id, mem_resource->resource_usage,
+ mem_resource->type_specific, mem_resource->granularity,
+ mem_resource->minimum, mem_resource->maximum,
+ mem_resource->translation_offset,
+ mem_resource->address_length);
+
+ if (mem_resource->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) {
+ ret = -ENODEV;
+ goto out_free;
+ }
+
+ pcch_virt_addr = ioremap_nocache(mem_resource->minimum,
+ mem_resource->address_length);
+ if (pcch_virt_addr == NULL) {
+ dprintk("probe: could not map shared mem region\n");
+ goto out_free;
+ }
+ pcch_hdr = pcch_virt_addr;
+
+ dprintk("probe: PCCH header (virtual) addr: 0x%p\n", pcch_hdr);
+ dprintk("probe: PCCH header is at physical address: 0x%llx,"
+ " signature: 0x%x, length: %d bytes, major: %d, minor: %d,"
+ " supported features: 0x%x, command field: 0x%x,"
+ " status field: 0x%x, nominal latency: %d us\n",
+ mem_resource->minimum, ioread32(&pcch_hdr->signature),
+ ioread16(&pcch_hdr->length), ioread8(&pcch_hdr->major),
+ ioread8(&pcch_hdr->minor), ioread32(&pcch_hdr->features),
+ ioread16(&pcch_hdr->command), ioread16(&pcch_hdr->status),
+ ioread32(&pcch_hdr->latency));
+
+ dprintk("probe: min time between commands: %d us,"
+ " max time between commands: %d us,"
+ " nominal CPU frequency: %d MHz,"
+ " minimum CPU frequency: %d MHz,"
+ " minimum CPU frequency without throttling: %d MHz\n",
+ ioread32(&pcch_hdr->minimum_time),
+ ioread32(&pcch_hdr->maximum_time),
+ ioread32(&pcch_hdr->nominal),
+ ioread32(&pcch_hdr->throttled_frequency),
+ ioread32(&pcch_hdr->minimum_frequency));
+
+ member = &out_obj->package.elements[1];
+ if (member->type != ACPI_TYPE_BUFFER) {
+ ret = -ENODEV;
+ goto pcch_free;
+ }
+
+ reg_resource = (struct pcc_register_resource *)member->buffer.pointer;
+
+ doorbell.space_id = reg_resource->space_id;
+ doorbell.bit_width = reg_resource->bit_width;
+ doorbell.bit_offset = reg_resource->bit_offset;
+ doorbell.access_width = 64;
+ doorbell.address = reg_resource->address;
+
+ dprintk("probe: doorbell: space_id is %d, bit_width is %d, "
+ "bit_offset is %d, access_width is %d, address is 0x%llx\n",
+ doorbell.space_id, doorbell.bit_width, doorbell.bit_offset,
+ doorbell.access_width, reg_resource->address);
+
+ member = &out_obj->package.elements[2];
+ if (member->type != ACPI_TYPE_INTEGER) {
+ ret = -ENODEV;
+ goto pcch_free;
+ }
+
+ doorbell_preserve = member->integer.value;
+
+ member = &out_obj->package.elements[3];
+ if (member->type != ACPI_TYPE_INTEGER) {
+ ret = -ENODEV;
+ goto pcch_free;
+ }
+
+ doorbell_write = member->integer.value;
+
+ dprintk("probe: doorbell_preserve: 0x%llx,"
+ " doorbell_write: 0x%llx\n",
+ doorbell_preserve, doorbell_write);
+
+ pcc_cpu_info = alloc_percpu(struct pcc_cpu);
+ if (!pcc_cpu_info) {
+ ret = -ENOMEM;
+ goto pcch_free;
+ }
+
+ printk(KERN_DEBUG "pcc-cpufreq: (v%s) driver loaded with frequency"
+ " limits: %d MHz, %d MHz\n", PCC_VERSION,
+ ioread32(&pcch_hdr->minimum_frequency),
+ ioread32(&pcch_hdr->nominal));
+ kfree(output.pointer);
+ return ret;
+pcch_free:
+ pcc_clear_mapping();
+out_free:
+ kfree(output.pointer);
+ return ret;
+}
+
+static int pcc_cpufreq_cpu_init(struct cpufreq_policy *policy)
+{
+ unsigned int cpu = policy->cpu;
+ unsigned int result = 0;
+
+ if (!pcch_virt_addr) {
+ result = -1;
+ goto pcch_null;
+ }
+
+ result = pcc_get_offset(cpu);
+ if (result) {
+ dprintk("init: PCCP evaluation failed\n");
+ goto free;
+ }
+
+ policy->max = policy->cpuinfo.max_freq =
+ ioread32(&pcch_hdr->nominal) * 1000;
+ policy->min = policy->cpuinfo.min_freq =
+ ioread32(&pcch_hdr->minimum_frequency) * 1000;
+ policy->cur = pcc_get_freq(cpu);
+
+ dprintk("init: policy->max is %d, policy->min is %d\n",
+ policy->max, policy->min);
+
+ return 0;
+free:
+ pcc_clear_mapping();
+ free_percpu(pcc_cpu_info);
+pcch_null:
+ return result;
+}
+
+static int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy)
+{
+ return 0;
+}
+
+static struct cpufreq_driver pcc_cpufreq_driver = {
+ .flags = CPUFREQ_CONST_LOOPS,
+ .get = pcc_get_freq,
+ .verify = pcc_cpufreq_verify,
+ .target = pcc_cpufreq_target,
+ .init = pcc_cpufreq_cpu_init,
+ .exit = pcc_cpufreq_cpu_exit,
+ .name = "pcc-cpufreq",
+ .owner = THIS_MODULE,
+};
+
+static int __init pcc_cpufreq_init(void)
+{
+ int ret;
+
+ if (acpi_disabled)
+ return 0;
+
+ ret = pcc_cpufreq_probe();
+ if (ret) {
+ dprintk("pcc_cpufreq_init: PCCH evaluation failed\n");
+ return ret;
+ }
+
+ ret = cpufreq_register_driver(&pcc_cpufreq_driver);
+
+ return ret;
+}
+
+static void __exit pcc_cpufreq_exit(void)
+{
+ cpufreq_unregister_driver(&pcc_cpufreq_driver);
+
+ pcc_clear_mapping();
+
+ free_percpu(pcc_cpu_info);
+}
+
+MODULE_AUTHOR("Matthew Garrett, Naga Chumbalkar");
+MODULE_VERSION(PCC_VERSION);
+MODULE_DESCRIPTION("Processor Clocking Control interface driver");
+MODULE_LICENSE("GPL");
+
+late_initcall(pcc_cpufreq_init);
+module_exit(pcc_cpufreq_exit);
projects / ~andy / linux / commitdiff