Commit a6cbcdd5 authored by Srinivas Pandruvada's avatar Srinivas Pandruvada Committed by Rafael J. Wysocki
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ACPI / CPPC: Add support for functional fixed hardware address 



The CPPC registers can also be accessed via functional fixed hardware
addresse(FFH) in X86. Add support by modifying cpc_read and cpc_write to
be able to read/write MSRs on x86 platform on per cpu basis.
Also with this change, acpi_cppc_processor_probe doesn't bail out if
address space id is not equal to PCC or memory address space and FFH
is supported on the system.

Signed-off-by: default avatarSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 5448f146

arch/x86/kernel/acpi/Makefile

+1 −0
Original line number Diff line number Diff line 
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/cppc_msr.c

0 → 100644
+58 −0
Original line number Diff line number Diff line 
/*

 * 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/cppc_acpi.c

+62 −13
Original line number Diff line number Diff line
@@ -579,6 +579,19 @@ static int register_pcc_channel(int pcc_subspace_idx) 
	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.

 *
@@ -728,10 +741,12 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr) 
					cpc_ptr->cpc_regs[i-2].sys_mem_vaddr = addr;

				}

			} else {

				/* Support only PCC and SYS MEM type regs */

				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;

			memcpy(&cpc_ptr->cpc_regs[i-2].cpc_entry.reg, gas_t, sizeof(*gas_t));
@@ -819,13 +834,43 @@ void acpi_cppc_processor_exit(struct acpi_processor *pr) 
}

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_register_resource *reg_res, u64 *val)

static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)

{

	int ret_val = 0;

	void __iomem *vaddr = 0;
@@ -841,6 +886,8 @@ static int cpc_read(struct cpc_register_resource *reg_res, u64 *val) 
		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);
@@ -867,7 +914,7 @@ static int cpc_read(struct cpc_register_resource *reg_res, u64 *val) 
	return ret_val;

}



static int cpc_write(struct cpc_register_resource *reg_res, u64 val)

static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)

{

	int ret_val = 0;

	void __iomem *vaddr = 0;
@@ -877,6 +924,8 @@ static int cpc_write(struct cpc_register_resource *reg_res, u64 val) 
		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);
@@ -941,13 +990,13 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps) 
		}

	}



	cpc_read(highest_reg, &high);

	cpc_read(cpunum, highest_reg, &high);

	perf_caps->highest_perf = high;



	cpc_read(lowest_reg, &low);

	cpc_read(cpunum, lowest_reg, &low);

	perf_caps->lowest_perf = low;



	cpc_read(nom_perf, &nom);

	cpc_read(cpunum, nom_perf, &nom);

	perf_caps->nominal_perf = nom;



	if (!high || !low || !nom)
@@ -1004,9 +1053,9 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs) 
		}

	}



	cpc_read(delivered_reg, &delivered);

	cpc_read(reference_reg, &reference);

	cpc_read(ref_perf_reg, &ref_perf);

	cpc_read(cpunum, delivered_reg, &delivered);

	cpc_read(cpunum, reference_reg, &reference);

	cpc_read(cpunum, ref_perf_reg, &ref_perf);



	/*

	 * Per spec, if ctr_wrap_time optional register is unsupported, then the
@@ -1015,7 +1064,7 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs) 
	 */

	ctr_wrap_time = (u64)(~((u64)0));

	if (CPC_SUPPORTED(ctr_wrap_reg))

		cpc_read(ctr_wrap_reg, &ctr_wrap_time);

		cpc_read(cpunum, ctr_wrap_reg, &ctr_wrap_time);



	if (!delivered || !reference ||	!ref_perf) {

		ret = -EFAULT;
@@ -1082,7 +1131,7 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls) 
	 * Skip writing MIN/MAX until Linux knows how to come up with

	 * useful values.

	 */

	cpc_write(desired_reg, perf_ctrls->desired_perf);

	cpc_write(cpu, desired_reg, perf_ctrls->desired_perf);



	if (CPC_IN_PCC(desired_reg))

		up_read(&pcc_data.pcc_lock);	/* END Phase-I */

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