Message-ID: <Y4ox5J0junaUYyT7@yilunxu-OptiPlex-7050>
Date:   Sat, 3 Dec 2022 01:12:04 +0800
From:   Xu Yilun <yilun.xu@...el.com>
To:     Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc:     linux-fpga@...r.kernel.org, Wu Hao <hao.wu@...el.com>,
        Tom Rix <trix@...hat.com>, Moritz Fischer <mdf@...nel.org>,
        Lee Jones <lee@...nel.org>,
        Matthew Gerlach <matthew.gerlach@...ux.intel.com>,
        Russ Weight <russell.h.weight@...el.com>,
        Tianfei zhang <tianfei.zhang@...el.com>,
        Mark Brown <broonie@...nel.org>,
        Greg KH <gregkh@...uxfoundation.org>,
        Marco Pagani <marpagan@...hat.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 7/9] mfd: intel-m10-bmc: Add PMCI driver

On 2022-12-02 at 12:08:39 +0200, Ilpo Järvinen wrote:
> Add the mfd driver for the Platform Management Component Interface
> (PMCI) based interface of Intel MAX10 BMC controller.
> 
> PMCI is a software-visible interface, connected to card BMC which
> provided the basic functionality of read/write BMC register. This
> driver leverages the regmap APIs to support Intel specific Indirect
> Register Interface for register read/write on PMCI.
> 
> Previously, intel-m10-bmc provided sysfs under
> /sys/bus/spi/devices/... which is generalized in this change because
> not all MAX10 BMC appear under SPI anymore.
> 
> This patch also adds support for indirect register access via a regmap
> interface. The access to the register goes via a hardware
> controller/bridge that handles read/write/clear commands and
> acknowledgments for the commands. On Intel FPGA IPs with e.g. PMCI or
> HSSI, indirect register access is a generic way to access registers.
> 
> Co-developed-by: Tianfei zhang <tianfei.zhang@...el.com>
> Signed-off-by: Tianfei zhang <tianfei.zhang@...el.com>
> Co-developed-by: Russ Weight <russell.h.weight@...el.com>
> Signed-off-by: Russ Weight <russell.h.weight@...el.com>
> Co-developed-by: Matthew Gerlach <matthew.gerlach@...ux.intel.com>
> Signed-off-by: Matthew Gerlach <matthew.gerlach@...ux.intel.com>
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
> ---
>  .../ABI/testing/sysfs-driver-intel-m10-bmc    |   8 +-
>  drivers/mfd/Kconfig                           |  12 ++
>  drivers/mfd/Makefile                          |   2 +
>  drivers/mfd/intel-m10-bmc-pmci-indirect.c     | 133 ++++++++++++++++
>  drivers/mfd/intel-m10-bmc-pmci-main.c         | 147 ++++++++++++++++++
>  include/linux/mfd/intel-m10-bmc.h             |  22 +++
>  6 files changed, 320 insertions(+), 4 deletions(-)
>  create mode 100644 drivers/mfd/intel-m10-bmc-pmci-indirect.c
>  create mode 100644 drivers/mfd/intel-m10-bmc-pmci-main.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
>  Date:		June 2020
>  KernelVersion:	5.10
>  Contact:	Xu Yilun <yilun.xu@...el.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@...el.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@...el.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@...el.com>
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index a09d4ac60dc7..82f13614d98a 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -2238,6 +2238,18 @@ 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
> +	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 5d1f308ee2a7..603c0a8f1241 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -274,6 +274,8 @@ obj-$(CONFIG_MFD_SIMPLE_MFD_I2C)	+= simple-mfd-i2c.o
>  
>  obj-$(CONFIG_MFD_INTEL_M10_BMC_CORE)	+= intel-m10-bmc-core.o
>  obj-$(CONFIG_MFD_INTEL_M10_BMC_SPI)	+= intel-m10-bmc-spi.o
> +intel-m10-bmc-pmci-objs			:= intel-m10-bmc-pmci-main.o intel-m10-bmc-pmci-indirect.o
> +obj-$(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-pmci-indirect.c b/drivers/mfd/intel-m10-bmc-pmci-indirect.c
> new file mode 100644
> index 000000000000..cf347f93c05d
> --- /dev/null
> +++ b/drivers/mfd/intel-m10-bmc-pmci-indirect.c
> @@ -0,0 +1,133 @@
> +// SPDX-License-Identifier: GPL-2.0
> +//
> +// Intel FGPA indirect register access via hardware controller/bridge.
> +//
> +// Copyright (C) 2020-2022 Intel Corporation.
> +
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +
> +#include <linux/mfd/intel-m10-bmc.h>
> +
> +#define INDIRECT_CMD_OFF	0
> +#define INDIRECT_CMD_CLR	0
> +#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
> +
> +#define INDIRECT_INT_US		1
> +#define INDIRECT_TIMEOUT_US	10000
> +
> +struct indirect_ctx {
> +	void __iomem *base;
> +	struct device *dev;
> +};
> +
> +static int indirect_bus_clear_cmd(struct indirect_ctx *ctx)
> +{
> +	unsigned int cmd;
> +	int ret;
> +
> +	writel(INDIRECT_CMD_CLR, ctx->base + INDIRECT_CMD_OFF);
> +
> +	ret = readl_poll_timeout(ctx->base + INDIRECT_CMD_OFF, cmd,
> +				 cmd == INDIRECT_CMD_CLR,
> +				 INDIRECT_INT_US, INDIRECT_TIMEOUT_US);
> +	if (ret)
> +		dev_err(ctx->dev, "timed out waiting clear cmd (residual cmd=0x%x)\n", cmd);
> +
> +	return ret;
> +}
> +
> +static int indirect_bus_reg_read(void *context, unsigned int reg,
> +				     unsigned int *val)
> +{
> +	struct indirect_ctx *ctx = context;
> +	unsigned int cmd, ack, tmpval;
> +	int ret;
> +
> +	cmd = readl(ctx->base + INDIRECT_CMD_OFF);
> +	if (cmd != INDIRECT_CMD_CLR)
> +		dev_warn(ctx->dev, "residual cmd 0x%x on read entry\n", 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, ack,
> +				 (ack & INDIRECT_CMD_ACK) == INDIRECT_CMD_ACK,
> +				 INDIRECT_INT_US, INDIRECT_TIMEOUT_US);
> +	if (ret)
> +		dev_err(ctx->dev, "read timed out on reg 0x%x ack 0x%x\n", reg, ack);
> +	else
> +		tmpval = readl(ctx->base + INDIRECT_RD_OFF);
> +
> +	if (indirect_bus_clear_cmd(ctx)) {
> +		if (!ret)
> +			ret = -ETIMEDOUT;
> +		goto out;
> +	}
> +
> +	*val = tmpval;
> +out:
> +	return ret;
> +}
> +
> +static int indirect_bus_reg_write(void *context, unsigned int reg,
> +				      unsigned int val)
> +{
> +	struct indirect_ctx *ctx = context;
> +	unsigned int cmd, ack;
> +	int ret;
> +
> +	cmd = readl(ctx->base + INDIRECT_CMD_OFF);
> +	if (cmd != INDIRECT_CMD_CLR)
> +		dev_warn(ctx->dev, "residual cmd 0x%x on write entry\n", 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, ack,
> +				 (ack & INDIRECT_CMD_ACK) == INDIRECT_CMD_ACK,
> +				 INDIRECT_INT_US, INDIRECT_TIMEOUT_US);
> +	if (ret)
> +		dev_err(ctx->dev, "write timed out on reg 0x%x ack 0x%x\n", reg, ack);
> +
> +	if (indirect_bus_clear_cmd(ctx)) {
> +		if (!ret)
> +			ret = -ETIMEDOUT;
> +	}
> +
> +	return ret;
> +}
> +
> +static const struct regmap_bus indirect_bus = {
> +	.reg_write = indirect_bus_reg_write,
> +	.reg_read =  indirect_bus_reg_read,
> +};
> +
> +struct regmap *__devm_m10_regmap_indirect(struct device *dev,

We name the file intel-m10-bmc-pmci-xxx.c, and this function
xx_m10_regmap_xx(). But I can see the implementation is just about the indirect
bus which from your commit message could be used by various DFL features
like HSSI or PMCI. So is it better we put the implementation in
drivers/fpga and name the file dfl-indirect-regmap.c and the
initialization function dfl_indirect_regmap_init()?

> +					  void __iomem *base,
> +					  struct regmap_config *cfg,
> +					  struct lock_class_key *lock_key,
> +					  const char *lock_name)
> +{
> +	struct indirect_ctx *ctx;
> +
> +	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
> +	if (!ctx)
> +		return NULL;
> +
> +	ctx->base = base;
> +	ctx->dev = dev;
> +
> +	indirect_bus_clear_cmd(ctx);
> +
> +	return __devm_regmap_init(dev, &indirect_bus, ctx, cfg, lock_key, lock_name);

Sorry, I just can't remember why don't we just call devm_regmap_init() and
get rid of all lock stuff?

> +}
> diff --git a/drivers/mfd/intel-m10-bmc-pmci-main.c b/drivers/mfd/intel-m10-bmc-pmci-main.c
> new file mode 100644
> index 000000000000..11e528b2f707
> --- /dev/null
> +++ b/drivers/mfd/intel-m10-bmc-pmci-main.c
> @@ -0,0 +1,147 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * MFD driver for Platform Management Component Interface (PMCI) based
> + * interface to MAX10 BMC.
> + *
> + * Copyright (C) 2020-2022 Intel Corporation.
> + *
> + */
> +
> +#include <linux/dfl.h>
> +#include <linux/mfd/core.h>
> +#include <linux/mfd/intel-m10-bmc.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +
> +#define M10BMC_PMCI_INDIRECT_BASE	0x400
> +
> +#define M10BMC_PMCI_SYS_BASE		0x0
> +#define M10BMC_PMCI_SYS_END		0xfff
> +
> +#define M10BMC_PMCI_DOORBELL		0x1c0
> +#define M10BMC_PMCI_AUTH_RESULT		0x1c4
> +
> +/* Telemetry registers */
> +#define M10BMC_PMCI_TELEM_START		0x400
> +#define M10BMC_PMCI_TELEM_END		0x78c
> +
> +#define M10BMC_PMCI_BUILD_VER		0x0
> +#define NIOS2_PMCI_FW_VERSION		0x4
> +#define M10BMC_PMCI_MAC_LOW		0x20
> +#define M10BMC_PMCI_MAC_HIGH		(M10BMC_PMCI_MAC_LOW + 4)
> +
> +/* Addresses for security related data in FLASH */
> +#define M10BMC_PMCI_BMC_REH_ADDR	0x7ffc004
> +#define M10BMC_PMCI_BMC_PROG_ADDR	0x7ffc000
> +#define M10BMC_PMCI_BMC_PROG_MAGIC	0x5746
> +
> +#define M10BMC_PMCI_SR_REH_ADDR		0x7ffd004
> +#define M10BMC_PMCI_SR_PROG_ADDR	0x7ffd000
> +#define M10BMC_PMCI_SR_PROG_MAGIC	0x5253
> +
> +#define M10BMC_PMCI_PR_REH_ADDR		0x7ffe004
> +#define M10BMC_PMCI_PR_PROG_ADDR	0x7ffe000
> +#define M10BMC_PMCI_PR_PROG_MAGIC	0x5250
> +
> +#define M10BMC_PMCI_STAGING_FLASH_COUNT	0x7ff5000

The same concern here, should all PMCI based M10 BMC have the same
register layout? I assume no. I still think the layout should be decided
by board type.

So some concern about these naming.

Thanks,
Yilun

> +
> +struct m10bmc_pmci_device {
> +	void __iomem *base;
> +	struct intel_m10bmc m10bmc;
> +};
> +
> +static const struct regmap_range m10bmc_pmci_regmap_range[] = {
> +	regmap_reg_range(M10BMC_PMCI_SYS_BASE, M10BMC_PMCI_SYS_END),
> +};
> +
> +static const struct regmap_access_table m10bmc_pmci_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 = &m10bmc_pmci_access_table,
> +	.rd_table = &m10bmc_pmci_access_table,
> +	.max_register = M10BMC_PMCI_SYS_END,
> +};
> +
> +static struct mfd_cell m10bmc_pmci_n6000_bmc_subdevs[] = {
> +	{ .name = "n6000bmc-hwmon" },
> +};
> +
> +static const struct m10bmc_csr_map m10bmc_pmci_csr_map = {
> +	.base = M10BMC_PMCI_SYS_BASE,
> +	.build_version = M10BMC_PMCI_BUILD_VER,
> +	.fw_version = NIOS2_PMCI_FW_VERSION,
> +	.mac_low = M10BMC_PMCI_MAC_LOW,
> +	.mac_high = M10BMC_PMCI_MAC_HIGH,
> +	.doorbell = M10BMC_PMCI_DOORBELL,
> +	.auth_result = M10BMC_PMCI_AUTH_RESULT,
> +	.bmc_prog_addr = M10BMC_PMCI_BMC_PROG_ADDR,
> +	.bmc_reh_addr = M10BMC_PMCI_BMC_REH_ADDR,
> +	.bmc_magic = M10BMC_PMCI_BMC_PROG_MAGIC,
> +	.sr_prog_addr = M10BMC_PMCI_SR_PROG_ADDR,
> +	.sr_reh_addr = M10BMC_PMCI_SR_REH_ADDR,
> +	.sr_magic = M10BMC_PMCI_SR_PROG_MAGIC,
> +	.pr_prog_addr = M10BMC_PMCI_PR_PROG_ADDR,
> +	.pr_reh_addr = M10BMC_PMCI_PR_REH_ADDR,
> +	.pr_magic = M10BMC_PMCI_PR_PROG_MAGIC,
> +	.rsu_update_counter = M10BMC_PMCI_STAGING_FLASH_COUNT,
> +};
> +
> +static const struct intel_m10bmc_platform_info m10bmc_pmci_n6000 = {
> +	.cells = m10bmc_pmci_n6000_bmc_subdevs,
> +	.n_cells = ARRAY_SIZE(m10bmc_pmci_n6000_bmc_subdevs),
> +	.csr_map = &m10bmc_pmci_csr_map,
> +};
> +
> +static int m10bmc_pmci_probe(struct dfl_device *ddev)
> +{
> +	struct device *dev = &ddev->dev;
> +	struct m10bmc_pmci_device *pmci;
> +
> +	pmci = devm_kzalloc(dev, sizeof(*pmci), GFP_KERNEL);
> +	if (!pmci)
> +		return -ENOMEM;
> +
> +	pmci->m10bmc.dev = dev;
> +
> +	pmci->base = devm_ioremap_resource(dev, &ddev->mmio_res);
> +	if (IS_ERR(pmci->base))
> +		return PTR_ERR(pmci->base);
> +
> +	pmci->m10bmc.regmap =
> +		devm_m10_regmap_indirect(dev,
> +					 pmci->base + M10BMC_PMCI_INDIRECT_BASE,
> +					 &m10bmc_pmci_regmap_config);
> +	if (IS_ERR(pmci->m10bmc.regmap))
> +		return PTR_ERR(pmci->m10bmc.regmap);
> +
> +	return m10bmc_dev_init(&pmci->m10bmc, &m10bmc_pmci_n6000);
> +}
> +
> +#define FME_FEATURE_ID_M10BMC_PMCI	0x12
> +
> +static const struct dfl_device_id m10bmc_pmci_ids[] = {
> +	{ FME_ID, FME_FEATURE_ID_M10BMC_PMCI },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(dfl, m10bmc_pmci_ids);
> +
> +static struct dfl_driver m10bmc_pmci_driver = {
> +	.drv	= {
> +		.name       = "intel-m10-bmc",
> +		.dev_groups = m10bmc_dev_groups,
> +	},
> +	.id_table = m10bmc_pmci_ids,
> +	.probe    = m10bmc_pmci_probe,
> +};
> +
> +module_dfl_driver(m10bmc_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 71ace732bb48..d0497046de5f 100644
> --- a/include/linux/mfd/intel-m10-bmc.h
> +++ b/include/linux/mfd/intel-m10-bmc.h
> @@ -161,4 +161,26 @@ static inline int m10bmc_sys_read(struct intel_m10bmc *m10bmc, unsigned int offs
>  int m10bmc_dev_init(struct intel_m10bmc *m10bmc, const struct intel_m10bmc_platform_info *info);
>  extern const struct attribute_group *m10bmc_dev_groups[];
>  
> +/*
> + * Intel FPGA indirect register access support
> + */
> +struct regmap *__devm_m10_regmap_indirect(struct device *dev,
> +					  void __iomem *base,
> +					  struct regmap_config *cfg,
> +					  struct lock_class_key *lock_key,
> +					  const char *lock_name);
> +
> +/**
> + * devm_m10_regmap_indirect - create a regmap for indirect register access
> + * @dev: device creating the regmap
> + * @base: __iomem point to base of memory with mailbox
> + * @cfg: regmap_config describing interface
> + *
> + * Return: 0 on success, negative error code otherwise.
> + */
> +#define devm_m10_regmap_indirect(dev, base, config)			\
> +	__regmap_lockdep_wrapper(__devm_m10_regmap_indirect, #config,	\
> +				 dev, base, config)
> +
> +
>  #endif /* __MFD_INTEL_M10_BMC_H */
> -- 
> 2.30.2
> 

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