Re: [PATCH v11 11/14] mfd: intel-peci-client: Add Intel PECI client driver

[Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>]

Hi Lee,

On 12/16/2019 8:01 AM, Lee Jones wrote:
> On Wed, 11 Dec 2019, Jae Hyun Yoo wrote:
> 
>> This commit adds Intel PECI client driver.
>>
>> Cc: Lee Jones <lee.jones@linaro.org>
>> Cc: Randy Dunlap <rdunlap@infradead.org>
>> Cc: Rob Herring <robh+dt@kernel.org>
>> Cc: Andrew Jeffery <andrew@aj.id.au>
>> Cc: James Feist <james.feist@linux.intel.com>
>> Cc: Jason M Biils <jason.m.bills@linux.intel.com>
>> Cc: Joel Stanley <joel@jms.id.au>
>> Cc: Vernon Mauery <vernon.mauery@linux.intel.com>
>> Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
>> ---
>> Changes since v10:
>> - Fixed minor style issues.
>>
>>   drivers/mfd/Kconfig                   |  17 +++
>>   drivers/mfd/Makefile                  |   1 +
>>   drivers/mfd/intel-peci-client.c       | 149 ++++++++++++++++++++++++++
>>   include/linux/mfd/intel-peci-client.h | 117 ++++++++++++++++++++
>>   4 files changed, 284 insertions(+)
>>   create mode 100644 drivers/mfd/intel-peci-client.c
>>   create mode 100644 include/linux/mfd/intel-peci-client.h
>>
>> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
>> index 420900852166..7022e54a4703 100644
>> --- a/drivers/mfd/Kconfig
>> +++ b/drivers/mfd/Kconfig
>> @@ -632,6 +632,23 @@ config MFD_INTEL_MSIC
>>   	  Passage) chip. This chip embeds audio, battery, GPIO, etc.
>>   	  devices used in Intel Medfield platforms.
>>   
>> +config MFD_INTEL_PECI_CLIENT
>> +	tristate "Intel PECI client"
>> +	depends on (PECI || COMPILE_TEST)
>> +	select MFD_CORE
>> +	help
>> +	  If you say yes to this option, support will be included for the
>> +	  Intel PECI (Platform Environment Control Interface) client. PECI is a
>> +	  one-wire bus interface that provides a communication channel from PECI
>> +	  clients in Intel processors and chipset components to external
>> +	  monitoring or control devices.
>> +
>> +	  Additional drivers must be enabled in order to use the functionality
>> +	  of the device.
>> +
>> +	  This driver can also be built as a module. If so, the module
>> +	  will be called intel-peci-client.
>> +
>>   config MFD_IPAQ_MICRO
>>   	bool "Atmel Micro ASIC (iPAQ h3100/h3600/h3700) Support"
>>   	depends on SA1100_H3100 || SA1100_H3600
>> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
>> index aed99f08739f..91c6fda5cec6 100644
>> --- a/drivers/mfd/Makefile
>> +++ b/drivers/mfd/Makefile
>> @@ -211,6 +211,7 @@ obj-$(CONFIG_MFD_INTEL_LPSS)	+= intel-lpss.o
>>   obj-$(CONFIG_MFD_INTEL_LPSS_PCI)	+= intel-lpss-pci.o
>>   obj-$(CONFIG_MFD_INTEL_LPSS_ACPI)	+= intel-lpss-acpi.o
>>   obj-$(CONFIG_MFD_INTEL_MSIC)	+= intel_msic.o
>> +obj-$(CONFIG_MFD_INTEL_PECI_CLIENT)	+= intel-peci-client.o
>>   obj-$(CONFIG_MFD_PALMAS)	+= palmas.o
>>   obj-$(CONFIG_MFD_VIPERBOARD)    += viperboard.o
>>   obj-$(CONFIG_MFD_RC5T583)	+= rc5t583.o rc5t583-irq.o
>> diff --git a/drivers/mfd/intel-peci-client.c b/drivers/mfd/intel-peci-client.c
>> new file mode 100644
>> index 000000000000..18bf0af0e09e
>> --- /dev/null
>> +++ b/drivers/mfd/intel-peci-client.c
>> @@ -0,0 +1,149 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +// Copyright (c) 2018-2019 Intel Corporation
>> +
>> +#include <linux/bitfield.h>
>> +#include <linux/mfd/core.h>
>> +#include <linux/mfd/intel-peci-client.h>
>> +#include <linux/module.h>
>> +#include <linux/of_device.h>
>> +#include <linux/peci.h>
>> +
>> +#define CPU_ID_MODEL_MASK      GENMASK(7, 4)
>> +#define CPU_ID_FAMILY_MASK     GENMASK(11, 8)
>> +#define CPU_ID_EXT_MODEL_MASK  GENMASK(19, 16)
>> +#define CPU_ID_EXT_FAMILY_MASK GENMASK(27, 20)
>> +
>> +#define LOWER_NIBBLE_MASK      GENMASK(3, 0)
>> +#define UPPER_NIBBLE_MASK      GENMASK(7, 4)
>> +#define LOWER_BYTE_MASK        GENMASK(7, 0)
>> +#define UPPER_BYTE_MASK        GENMASK(16, 8)
>> +
>> +static struct mfd_cell peci_functions[] = {
>> +	{ .name = "peci-cputemp", },
>> +	{ .name = "peci-dimmtemp", },
>> +	/* TODO: Add additional PECI sideband functions into here */
> 
> No need for this comment.  It's implied.

I see. I'll remove this comment.

>> +};
>> +
>> +static const struct cpu_gen_info cpu_gen_info_table[] = {
>> +	{ /* Haswell Xeon */
>> +		.family        = 6, /* Family code */
> 
> Nit: Why don't you just define the number, instead of feeling the need
> to further clarify by providing a comment?

Makes sense. Will define the number.

>> +		.model         = INTEL_FAM6_HASWELL_X,
>> +		.core_max      = CORE_MAX_ON_HSX,
>> +		.chan_rank_max = CHAN_RANK_MAX_ON_HSX,
>> +		.dimm_idx_max  = DIMM_IDX_MAX_ON_HSX },
>> +	{ /* Broadwell Xeon */
>> +		.family        = 6, /* Family code */
>> +		.model         = INTEL_FAM6_BROADWELL_X,
>> +		.core_max      = CORE_MAX_ON_BDX,
>> +		.chan_rank_max = CHAN_RANK_MAX_ON_BDX,
>> +		.dimm_idx_max  = DIMM_IDX_MAX_ON_BDX },
>> +	{ /* Skylake Xeon */
>> +		.family        = 6, /* Family code */
>> +		.model         = INTEL_FAM6_SKYLAKE_X,
>> +		.core_max      = CORE_MAX_ON_SKX,
>> +		.chan_rank_max = CHAN_RANK_MAX_ON_SKX,
>> +		.dimm_idx_max  = DIMM_IDX_MAX_ON_SKX },
>> +	{ /* Skylake Xeon D */
>> +		.family        = 6, /* Family code */
>> +		.model         = INTEL_FAM6_SKYLAKE_XD,
>> +		.core_max      = CORE_MAX_ON_SKXD,
>> +		.chan_rank_max = CHAN_RANK_MAX_ON_SKXD,
>> +		.dimm_idx_max  = DIMM_IDX_MAX_ON_SKXD },
>> +};
>> +
>> +static int peci_client_get_cpu_gen_info(struct peci_client_manager *priv)
>> +{
>> +	struct device *dev = &priv->client->dev;
>> +	u32 cpu_id;
>> +	u16 family;
>> +	u8 model;
>> +	int ret;
>> +	int i;
>> +
>> +	ret = peci_get_cpu_id(priv->client->adapter, priv->client->addr,
>> +			      &cpu_id);
>> +	if (ret)
>> +		return ret;
>> +
>> +	family = FIELD_PREP(LOWER_BYTE_MASK,
>> +			    FIELD_GET(CPU_ID_FAMILY_MASK, cpu_id)) |
>> +		 FIELD_PREP(UPPER_BYTE_MASK,
>> +			    FIELD_GET(CPU_ID_EXT_FAMILY_MASK, cpu_id));
>> +	model = FIELD_PREP(LOWER_NIBBLE_MASK,
>> +			   FIELD_GET(CPU_ID_MODEL_MASK, cpu_id)) |
>> +		FIELD_PREP(UPPER_NIBBLE_MASK,
>> +			   FIELD_GET(CPU_ID_EXT_MODEL_MASK, cpu_id));
>> +
>> +	for (i = 0; i < ARRAY_SIZE(cpu_gen_info_table); i++) {
>> +		const struct cpu_gen_info *cpu_info = &cpu_gen_info_table[i];
>> +
>> +		if (family == cpu_info->family && model == cpu_info->model) {
>> +			priv->gen_info = cpu_info;
>> +			break;
>> +		}
>> +	}
>> +
>> +	if (!priv->gen_info) {
>> +		dev_err(dev, "Can't support this CPU: 0x%x\n", cpu_id);
>> +		ret = -ENODEV;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static int peci_client_probe(struct peci_client *client)
>> +{
>> +	struct device *dev = &client->dev;
>> +	struct peci_client_manager *priv;
>> +	uint cpu_no;
>> +	int ret;
>> +
>> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>> +	if (!priv)
>> +		return -ENOMEM;
>> +
>> +	dev_set_drvdata(dev, priv);
>> +	priv->client = client;
>> +	cpu_no = client->addr - PECI_BASE_ADDR;
>> +
>> +	ret = peci_client_get_cpu_gen_info(priv);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = devm_mfd_add_devices(dev, cpu_no, peci_functions,
>> +				   ARRAY_SIZE(peci_functions), NULL, 0, NULL);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to register child devices: %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +#if IS_ENABLED(CONFIG_OF)
> 
> #ifdef CONFIG_OF

Will fix it.

>> +static const struct of_device_id peci_client_of_table[] = {
>> +	{ .compatible = "intel,peci-client" },
>> +	{ }
>> +};
>> +MODULE_DEVICE_TABLE(of, peci_client_of_table);
>> +#endif /* CONFIG_OF */
> 
> Please remove this comment.  It doesn't provide anything here.

I see. I'll remove this comment.

>> +static const struct peci_device_id peci_client_ids[] = {
>> +	{ .name = "peci-client" },
>> +	{ }
>> +};
>> +MODULE_DEVICE_TABLE(peci, peci_client_ids);
> 
> Is this a requirement?  If so, why?
> 
> We're trying to get rid of unnecessary tables.
> 
> Please grep for "probe_new".

This is needed because peci-core.c provides sub tree searching while
registering a peci bus using of_match_device, also it provides
runtime registration through sysfs interface using ID match just like
I2C subsystem does. The probe member in 'struct peci_driver' is defined
as the new style like this:

struct peci_driver {
	int (*probe)(struct peci_client *client);
	[....]
}

>> +static struct peci_driver peci_client_driver = {
>> +	.probe    = peci_client_probe,
>> +	.id_table = peci_client_ids,
>> +	.driver   = {
>> +		.name           = KBUILD_MODNAME,
>> +		.of_match_table = of_match_ptr(peci_client_of_table),
>> +	},
>> +};
>> +module_peci_driver(peci_client_driver);
>> +
>> +MODULE_AUTHOR("Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>");
>> +MODULE_DESCRIPTION("PECI client driver");
>> +MODULE_LICENSE("GPL v2");
>> diff --git a/include/linux/mfd/intel-peci-client.h b/include/linux/mfd/intel-peci-client.h
>> new file mode 100644
>> index 000000000000..9854303bbc26
>> --- /dev/null
>> +++ b/include/linux/mfd/intel-peci-client.h
>> @@ -0,0 +1,117 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/* Copyright (c) 2018-2019 Intel Corporation */
>> +
>> +#ifndef __LINUX_MFD_INTEL_PECI_CLIENT_H
>> +#define __LINUX_MFD_INTEL_PECI_CLIENT_H
>> +
>> +#include <linux/peci.h>
>> +
>> +#if IS_ENABLED(CONFIG_X86)
>> +#include <asm/intel-family.h>
>> +#else
>> +/*
>> + * Architectures other than x86 cannot include the header file so define these
>> + * at here. These are needed for detecting type of client x86 CPUs behind a PECI
>> + * connection.
>> + */
>> +#define INTEL_FAM6_HASWELL_X		0x3F
>> +#define INTEL_FAM6_BROADWELL_X		0x4F
>> +#define INTEL_FAM6_SKYLAKE_X		0x55
>> +#define INTEL_FAM6_SKYLAKE_XD		0x56
>> +#endif
>> +
>> +#define CORE_MAX_ON_HSX        18 /* Max number of cores on Haswell */
>> +#define CHAN_RANK_MAX_ON_HSX   8  /* Max number of channel ranks on Haswell */
>> +#define DIMM_IDX_MAX_ON_HSX    3  /* Max DIMM index per channel on Haswell */
>> +
>> +#define CORE_MAX_ON_BDX        24 /* Max number of cores on Broadwell */
>> +#define CHAN_RANK_MAX_ON_BDX   4  /* Max number of channel ranks on Broadwell */
>> +#define DIMM_IDX_MAX_ON_BDX    3  /* Max DIMM index per channel on Broadwell */
>> +
>> +#define CORE_MAX_ON_SKX        28 /* Max number of cores on Skylake */
>> +#define CHAN_RANK_MAX_ON_SKX   6  /* Max number of channel ranks on Skylake */
>> +#define DIMM_IDX_MAX_ON_SKX    2  /* Max DIMM index per channel on Skylake */
>> +
>> +#define CORE_MAX_ON_SKXD       16 /* Max number of cores on Skylake D */
>> +#define CHAN_RANK_MAX_ON_SKXD  2  /* Max number of channel ranks on Skylake D */
>> +#define DIMM_IDX_MAX_ON_SKXD   2  /* Max DIMM index per channel on Skylake D */
>> +
>> +#define CORE_NUMS_MAX          CORE_MAX_ON_SKX
>> +#define CHAN_RANK_MAX          CHAN_RANK_MAX_ON_HSX
>> +#define DIMM_IDX_MAX           DIMM_IDX_MAX_ON_HSX
>> +#define DIMM_NUMS_MAX          (CHAN_RANK_MAX * DIMM_IDX_MAX)
>> +
>> +/**
>> + * struct cpu_gen_info - CPU generation specific information
>> + * @family: CPU family ID
>> + * @model: CPU model
>> + * @core_max: max number of cores
>> + * @chan_rank_max: max number of channel ranks
>> + * @dimm_idx_max: max number of DIMM indices
>> + *
>> + * CPU generation specific information to identify maximum number of cores and
>> + * DIMM slots.
>> + */
>> +struct cpu_gen_info {
>> +	u16  family;
>> +	u8   model;
>> +	uint core_max;
>> +	uint chan_rank_max;
>> +	uint dimm_idx_max;
>> +};
>> +
>> +/**
>> + * struct peci_client_manager - PECI client manager information
>> + * @client; pointer to the PECI client
>> + * @name: PECI client manager name
>> + * @gen_info: CPU generation info of the detected CPU
>> + *
>> + * PECI client manager information for managing PECI sideband functions on a CPU
>> + * client.
>> + */
>> +struct peci_client_manager {
>> +	struct peci_client *client;
>> +	char name[PECI_NAME_SIZE];
>> +	const struct cpu_gen_info *gen_info;
>> +};
>> +
>> +/**
>> + * peci_client_read_package_config - read from the Package Configuration Space
>> + * @priv: driver private data structure
>> + * @index: encoding index for the requested service
>> + * @param: parameter to specify the exact data being requested
>> + * @data: data buffer to store the result
>> + * Context: can sleep
>> + *
>> + * A generic PECI command that provides read access to the
>> + * "Package Configuration Space" that is maintained by the PCU, including
>> + * various power and thermal management functions. Typical PCS read services
>> + * supported by the processor may include access to temperature data, energy
>> + * status, run time information, DIMM temperatures and so on.
>> + *
>> + * Return: zero on success, else a negative error code.
>> + */
>> +static inline int
>> +peci_client_read_package_config(struct peci_client_manager *priv,
>> +				u8 index, u16 param, u8 *data)
>> +{
>> +	struct peci_rd_pkg_cfg_msg msg;
>> +	int ret;
>> +
>> +	msg.addr = priv->client->addr;
>> +	msg.index = index;
>> +	msg.param = param;
>> +	msg.rx_len = 4;
>> +
>> +	ret = peci_command(priv->client->adapter, PECI_CMD_RD_PKG_CFG, &msg);
>> +	if (msg.cc != PECI_DEV_CC_SUCCESS)
>> +		ret = -EAGAIN;
>> +	if (ret)
>> +		return ret;
>> +
>> +	memcpy(data, msg.pkg_config, 4);
>> +
>> +	return 0;
>> +}
> 
> Where is this function used?

This function is used in MFD cell drivers that are included in this
patch set, peci-cputemp and peci-dimmtemp drivers. I moved it from
intel-peci-client.c to this header file as you commented in the previous
review spin. I also thought about moving it into peci-hwmon.h but
this command macro is a generic thing for Intel CPUs so I moved into
here.

Thanks a lot for your review!

-Jae

>> +#endif /* __LINUX_MFD_INTEL_PECI_CLIENT_H */
>