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Date:   Mon, 20 Jun 2022 19:55:08 +0800
From:   Xu Yilun <yilun.xu@intel.com>
To:     Tianfei Zhang <tianfei.zhang@intel.com>
Cc:     lee.jones@linaro.org, hao.wu@intel.com, trix@redhat.com,
        linux-kernel@vger.kernel.org, linux-fpga@vger.kernel.org,
        russell.h.weight@intel.com, matthew.gerlach@linux.intel.com
Subject: Re: [PATCH v2 3/4] mfd: intel-m10-bmc: add PMCI driver
Message-ID: <20220620115508.GC1319418@yilunxu-OptiPlex-7050>
References: <20220617020405.128352-1-tianfei.zhang@intel.com>
 <20220617020405.128352-4-tianfei.zhang@intel.com>
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In-Reply-To: <20220617020405.128352-4-tianfei.zhang@intel.com>
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On Thu, Jun 16, 2022 at 10:04:04PM -0400, Tianfei Zhang wrote:
> Adding a driver for the PMCI-base interface of Intel MAX10
> BMC controller.
> 
> PMCI(Platform Management Control Interface) is a software-visible
> interface, connected to card BMC which provided telemetry and mailbox

The PMCI interface or the BMC provides the telemetry functionality?

Maybe you should first describe the basic register access
functionality for PMCI interface. This is the main purpose of this
patch.

> functionalities. On the other hand, this driver leverages the regmap
> APIs to support Intel specific Indirect Register Interface for register
> read/write on PMCI.
> 
> Signed-off-by: Tianfei Zhang <tianfei.zhang@intel.com>
> Signed-off-by: Russ Weight <russell.h.weight@intel.com>
> Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
> ---
> v2:
>   - fix compile warning reported by lkp
>   - use regmap API for Indirect Register Interface.
> ---
>  .../ABI/testing/sysfs-driver-intel-m10-bmc    |   8 +-
>  drivers/mfd/Kconfig                           |  12 ++
>  drivers/mfd/Makefile                          |   1 +
>  drivers/mfd/intel-m10-bmc-core.c              |  19 +-
>  drivers/mfd/intel-m10-bmc-pmci.c              | 190 ++++++++++++++++++

Refering to intel-m10-bmc-spi.c, this is the DFL bus driver, PMCI is just
its internal register accessing implementation.

So maybe intel-m10-bmc-dfl.c?

>  include/linux/mfd/intel-m10-bmc.h             |   8 +
>  6 files changed, 230 insertions(+), 8 deletions(-)
>  create mode 100644 drivers/mfd/intel-m10-bmc-pmci.c
> 
> diff --git a/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc
> index 9773925138af..a8ab58035c95 100644
> --- a/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc
> +++ b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc
> @@ -1,4 +1,4 @@
> -What:		/sys/bus/spi/devices/.../bmc_version
> +What:		/sys/bus/.../drivers/intel-m10-bmc/.../bmc_version

The same driver for both PMCI & spi? From your patch, the pmci driver is
named "dfl-pmci-bmc", is it?

>  Date:		June 2020
>  KernelVersion:	5.10
>  Contact:	Xu Yilun <yilun.xu@intel.com>
> @@ -6,7 +6,7 @@ Description:	Read only. Returns the hardware build version of Intel
>  		MAX10 BMC chip.
>  		Format: "0x%x".
>  
> -What:		/sys/bus/spi/devices/.../bmcfw_version
> +What:		/sys/bus/.../drivers/intel-m10-bmc/.../bmcfw_version
>  Date:		June 2020
>  KernelVersion:	5.10
>  Contact:	Xu Yilun <yilun.xu@intel.com>
> @@ -14,7 +14,7 @@ Description:	Read only. Returns the firmware version of Intel MAX10
>  		BMC chip.
>  		Format: "0x%x".
>  
> -What:		/sys/bus/spi/devices/.../mac_address
> +What:		/sys/bus/.../drivers/intel-m10-bmc/.../mac_address
>  Date:		January 2021
>  KernelVersion:  5.12
>  Contact:	Russ Weight <russell.h.weight@intel.com>
> @@ -25,7 +25,7 @@ Description:	Read only. Returns the first MAC address in a block
>  		space.
>  		Format: "%02x:%02x:%02x:%02x:%02x:%02x".
>  
> -What:		/sys/bus/spi/devices/.../mac_count
> +What:		/sys/bus/.../drivers/intel-m10-bmc/.../mac_count
>  Date:		January 2021
>  KernelVersion:  5.12
>  Contact:	Russ Weight <russell.h.weight@intel.com>
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index ee8398b02321..7300efec3617 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -2177,6 +2177,18 @@ config MFD_INTEL_M10_BMC_SPI
>            additional drivers must be enabled in order to use the functionality
>            of the device.
>  
> +config MFD_INTEL_M10_BMC_PMCI
> +	tristate "Intel MAX 10 Board Management Controller with PMCI"
> +	depends on FPGA_DFL
> +	select MFD_INTEL_M10_BMC_CORE
> +	select REGMAP_INDIRECT_REGISTER
> +	help
> +	  Support for the Intel MAX 10 board management controller via PMCI.
> +
> +	  This driver provides common support for accessing the device,
> +	  additional drivers must be enabled in order to use the functionality
> +	  of the device.
> +
>  config MFD_RSMU_I2C
>  	tristate "Renesas Synchronization Management Unit with I2C"
>  	depends on I2C && OF
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index b5d3263c1205..a8ffdc223cf7 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -270,6 +270,7 @@ obj-$(CONFIG_MFD_SIMPLE_MFD_I2C)	+= simple-mfd-i2c.o
>  intel-m10-bmc-objs             := intel-m10-bmc-core.o
>  obj-$(CONFIG_MFD_INTEL_M10_BMC_CORE)   += intel-m10-bmc.o
>  obj-$(CONFIG_MFD_INTEL_M10_BMC_SPI)   += intel-m10-bmc-spi.o
> +obj-$(CONFIG_MFD_INTEL_M10_BMC_PMCI)  += intel-m10-bmc-pmci.o
>  
>  obj-$(CONFIG_MFD_ATC260X)	+= atc260x-core.o
>  obj-$(CONFIG_MFD_ATC260X_I2C)	+= atc260x-i2c.o
> diff --git a/drivers/mfd/intel-m10-bmc-core.c b/drivers/mfd/intel-m10-bmc-core.c
> index f6dc549e1bc3..c6a1a4c28357 100644
> --- a/drivers/mfd/intel-m10-bmc-core.c
> +++ b/drivers/mfd/intel-m10-bmc-core.c
> @@ -10,6 +10,11 @@
>  #include <linux/mfd/intel-m10-bmc.h>
>  #include <linux/module.h>
>  
> +static struct mfd_cell m10bmc_n6000_bmc_subdevs[] = {
> +	{ .name = "n6000bmc-hwmon" },
> +	{ .name = "n6000bmc-sec-update" }
> +};
> +
>  static struct mfd_cell m10bmc_d5005_subdevs[] = {
>  	{ .name = "d5005bmc-hwmon" },
>  };
> @@ -146,10 +151,12 @@ int m10bmc_dev_init(struct intel_m10bmc *m10bmc)
>  
>  	dev_set_drvdata(m10bmc->dev, m10bmc);
>  
> -	ret = check_m10bmc_version(m10bmc);
> -	if (ret) {
> -		dev_err(m10bmc->dev, "Failed to identify m10bmc hardware\n");
> -		return ret;
> +	if (type == M10_N3000 || type == M10_D5005 || type == M10_N5010) {
> +		ret = check_m10bmc_version(m10bmc);
> +		if (ret) {
> +			dev_err(m10bmc->dev, "Failed to identify m10bmc hardware\n");
> +			return ret;
> +		}
>  	}
>  
>  	switch (type) {
> @@ -165,6 +172,10 @@ int m10bmc_dev_init(struct intel_m10bmc *m10bmc)
>  		cells = m10bmc_n5010_subdevs;
>  		n_cell = ARRAY_SIZE(m10bmc_n5010_subdevs);
>  		break;
> +	case M10_N6000:
> +		cells = m10bmc_n6000_bmc_subdevs;
> +		n_cell = ARRAY_SIZE(m10bmc_n6000_bmc_subdevs);
> +		break;
>  	default:
>  		return -ENODEV;
>  	}
> diff --git a/drivers/mfd/intel-m10-bmc-pmci.c b/drivers/mfd/intel-m10-bmc-pmci.c
> new file mode 100644
> index 000000000000..249a2db5e742
> --- /dev/null
> +++ b/drivers/mfd/intel-m10-bmc-pmci.c
> @@ -0,0 +1,190 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * PMCI-based interface to MAX10 BMC
> + *
> + * Copyright (C) 2020-2022 Intel Corporation, Inc.
> + *
> + */
> +
> +#include <linux/dfl.h>
> +#include <linux/mfd/intel-m10-bmc.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +
> +#define M10BMC_PMCI_INDIRECT_BASE 0x400
> +#define INDIRECT_INT_US        1
> +#define INDIRECT_TIMEOUT_US    10000
> +
> +#define INDIRECT_CMD_OFF	0x0
> +#define INDIRECT_CMD_RD	BIT(0)
> +#define INDIRECT_CMD_WR	BIT(1)
> +#define INDIRECT_CMD_ACK	BIT(2)
> +
> +#define INDIRECT_ADDR_OFF	0x4
> +#define INDIRECT_RD_OFF	0x8
> +#define INDIRECT_WR_OFF	0xc
> +
> +struct indirect_ctx {
> +	void __iomem *base;
> +	struct device *dev;
> +	unsigned long sleep_us;
> +	unsigned long timeout_us;
> +};
> +
> +struct pmci_device {
> +	void __iomem *base;
> +	struct device *dev;
> +	struct intel_m10bmc m10bmc;
> +	struct indirect_ctx ctx;
> +};
> +
> +static int pmci_indirect_bus_clr_cmd(struct indirect_ctx *ctx)
> +{
> +	unsigned int cmd;
> +	int ret;
> +
> +	writel(0, ctx->base + INDIRECT_CMD_OFF);
> +	ret = readl_poll_timeout((ctx->base + INDIRECT_CMD_OFF), cmd,
> +				 (!cmd), ctx->sleep_us, ctx->timeout_us);
> +	if (ret)
> +		dev_err(ctx->dev, "%s timed out on clearing cmd 0x%xn", __func__, cmd);
> +
> +	return ret;
> +}
> +
> +static int pmci_indirect_bus_reg_read(void *context, unsigned int reg,
> +				      unsigned int *val)
> +{
> +	struct indirect_ctx *ctx = context;
> +	unsigned int cmd;
> +	int ret;
> +
> +	cmd = readl(ctx->base + INDIRECT_CMD_OFF);
> +	if (cmd)
> +		dev_warn(ctx->dev, "%s non-zero cmd 0x%x\n", __func__, cmd);
> +
> +	writel(reg, ctx->base + INDIRECT_ADDR_OFF);
> +	writel(INDIRECT_CMD_RD, ctx->base + INDIRECT_CMD_OFF);
> +	ret = readl_poll_timeout((ctx->base + INDIRECT_CMD_OFF), cmd,
> +				 (cmd & INDIRECT_CMD_ACK), ctx->sleep_us,
> +				 ctx->timeout_us);
> +	if (ret) {
> +		dev_err(ctx->dev, "%s timed out on reg 0x%x cmd 0x%x\n", __func__, reg, cmd);
> +		goto out;
> +	}
> +
> +	*val = readl(ctx->base + INDIRECT_RD_OFF);
> +
> +	if (pmci_indirect_bus_clr_cmd(ctx))
> +		ret = -ETIMEDOUT;
> +
> +out:
> +	return ret;
> +}
> +
> +static int pmci_indirect_bus_reg_write(void *context, unsigned int reg,
> +				       unsigned int val)
> +{
> +	struct indirect_ctx *ctx = context;
> +	unsigned int cmd;
> +	int ret;
> +
> +	cmd = readl(ctx->base + INDIRECT_CMD_OFF);
> +	if (cmd)
> +		dev_warn(ctx->dev, "%s non-zero cmd 0x%x\n", __func__, cmd);
> +
> +	writel(val, ctx->base + INDIRECT_WR_OFF);
> +	writel(reg, ctx->base + INDIRECT_ADDR_OFF);
> +	writel(INDIRECT_CMD_WR, ctx->base + INDIRECT_CMD_OFF);
> +	ret = readl_poll_timeout((ctx->base + INDIRECT_CMD_OFF), cmd,
> +				 (cmd & INDIRECT_CMD_ACK), ctx->sleep_us,
> +				 ctx->timeout_us);
> +	if (ret) {
> +		dev_err(ctx->dev, "%s timed out on reg 0x%x cmd 0x%x\n", __func__, reg, cmd);
> +		goto out;
> +	}
> +
> +	if (pmci_indirect_bus_clr_cmd(ctx))
> +		ret = -ETIMEDOUT;
> +
> +out:
> +	return ret;
> +}
> +
> +static const struct regmap_bus pmci_indirect_bus = {
> +	.reg_write = pmci_indirect_bus_reg_write,
> +	.reg_read =  pmci_indirect_bus_reg_read,
> +};
> +
> +static const struct regmap_range m10bmc_pmci_regmap_range[] = {
> +	regmap_reg_range(M10BMC_PMCI_SYS_BASE, M10BMC_PMCI_SYS_END),
> +};

If you have just one range, why bother defining it?

> +
> +static const struct regmap_access_table m10_access_table = {
> +	.yes_ranges	= m10bmc_pmci_regmap_range,
> +	.n_yes_ranges	= ARRAY_SIZE(m10bmc_pmci_regmap_range),
> +};
> +
> +static struct regmap_config m10bmc_pmci_regmap_config = {
> +	.reg_bits = 32,
> +	.reg_stride = 4,
> +	.val_bits = 32,
> +	.wr_table = &m10_access_table,
> +	.rd_table = &m10_access_table,
> +	.max_register = M10BMC_PMCI_SYS_END,
> +};

The same concern, these should be specific to BMC, not PMCI interface,
is it?

> +
> +static int pmci_probe(struct dfl_device *ddev)
> +{
> +	struct device *dev = &ddev->dev;
> +	struct pmci_device *pmci;
> +
> +	pmci = devm_kzalloc(dev, sizeof(*pmci), GFP_KERNEL);
> +	if (!pmci)
> +		return -ENOMEM;
> +
> +	pmci->m10bmc.dev = dev;
> +	pmci->dev = dev;
> +	pmci->m10bmc.type = M10_N6000;

The DFL feature only binds to N6000 BMC? Then the driver should be named
dfl-n6000-bmc I think.

> +
> +	pmci->base = devm_ioremap_resource(dev, &ddev->mmio_res);
> +	if (IS_ERR(pmci->base))
> +		return PTR_ERR(pmci->base);
> +
> +	pmci->ctx.base = pmci->base + M10BMC_PMCI_INDIRECT_BASE;
> +	pmci->ctx.sleep_us = INDIRECT_INT_US;
> +	pmci->ctx.timeout_us = INDIRECT_TIMEOUT_US;
> +	pmci->ctx.dev = dev;
> +	pmci->m10bmc.regmap =
> +		devm_regmap_init(dev,
> +				 &pmci_indirect_bus,
> +				 &pmci->ctx,
> +				 &m10bmc_pmci_regmap_config);
> +	if (IS_ERR(pmci->m10bmc.regmap))
> +		return PTR_ERR(pmci->m10bmc.regmap);
> +
> +	return m10bmc_dev_init(&pmci->m10bmc);
> +}
> +
> +#define FME_FEATURE_ID_PMCI_BMC	0x12
> +
> +static const struct dfl_device_id pmci_ids[] = {
> +	{ FME_ID, FME_FEATURE_ID_PMCI_BMC },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(dfl, pmci_ids);
> +
> +static struct dfl_driver pmci_driver = {
> +	.drv	= {
> +		.name       = "dfl-pmci-bmc",
> +		.dev_groups = m10bmc_dev_groups,
> +	},
> +	.id_table = pmci_ids,
> +	.probe    = pmci_probe,
> +};
> +
> +module_dfl_driver(pmci_driver);
> +
> +MODULE_DESCRIPTION("MAX10 BMC PMCI-based interface");
> +MODULE_AUTHOR("Intel Corporation");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/mfd/intel-m10-bmc.h b/include/linux/mfd/intel-m10-bmc.h
> index dd81ffdcf168..83c4d3993dcb 100644
> --- a/include/linux/mfd/intel-m10-bmc.h
> +++ b/include/linux/mfd/intel-m10-bmc.h
> @@ -118,11 +118,19 @@
>  /* Address of 4KB inverted bit vector containing staging area FLASH count */
>  #define STAGING_FLASH_COUNT	0x17ffb000
>  
> +#define M10BMC_PMCI_SYS_BASE 0x0
> +#define M10BMC_PMCI_SYS_END  0xfff
> +
> +/* Telemetry registers */
> +#define M10BMC_PMCI_TELEM_START		0x400
> +#define M10BMC_PMCI_TELEM_END		0x78c

The same concern, I asumme they are specific to BMC, not PMCI interface.

Thanks,
Yilun

> +
>  /* Supported MAX10 BMC types */
>  enum m10bmc_type {
>  	M10_N3000,
>  	M10_D5005,
>  	M10_N5010,
> +	M10_N6000
>  };
>  
>  /**
> -- 
> 2.26.2