linux-kernel - Re: [PATCH v1 1/1] mfd: intel-m10-bmc: expose mac address and count

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Date:   Wed, 2 Dec 2020 05:44:13 -0800
From:   Tom Rix <trix@...hat.com>
To:     Russ Weight <russell.h.weight@...el.com>, lee.jones@...aro.org,
        linux-kernel@...r.kernel.org
Cc:     lgoncalv@...hat.com, yilun.xu@...el.com, hao.wu@...el.com,
        matthew.gerlach@...el.com
Subject: Re: [PATCH v1 1/1] mfd: intel-m10-bmc: expose mac address and count


On 12/1/20 12:36 PM, Russ Weight wrote:
> Create two sysfs entries for exposing the MAC address
> and count from the MAX10 BMC register space.
>
> Signed-off-by: Russ Weight <russell.h.weight@...el.com>
> Signed-off-by: Xu Yilun <yilun.xu@...el.com>
> ---
>  .../ABI/testing/sysfs-driver-intel-m10-bmc    | 20 +++++++++
>  drivers/mfd/intel-m10-bmc.c                   | 43 +++++++++++++++++++
>  include/linux/mfd/intel-m10-bmc.h             |  9 ++++
>  3 files changed, 72 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc
> index 979a2d62513f..c4febaefe0a7 100644
> --- a/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc
> +++ b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc
> @@ -13,3 +13,23 @@ Contact:	Xu Yilun <yilun.xu@...el.com>
>  Description:	Read only. Returns the firmware version of Intel MAX10
>  		BMC chip.
>  		Format: "0x%x".
> +
> +What:		/sys/bus/spi/devices/.../mac_address
> +Date:		December 2020
> +KernelVersion:  5.11
> +Contact:	Russ Weight <russell.h.weight@...el.com>
> +Description:	Read only. Returns the base mac address assigned to
> +		the board managed by the Intel MAX10 BMC. It is
> +		stored in flash and is mirrored in the MAX10 BMC
> +		register space.
> +		Format: "%02x:%02x:%02x:%02x:%02x:%02x".
> +
> +What:		/sys/bus/spi/devices/.../mac_count
> +Date:		December 2020
> +KernelVersion:  5.11
> +Contact:	Russ Weight <russell.h.weight@...el.com>
> +Description:	Read only. Returns the number of mac addresses
> +		assigned to the board managed by the Intel MAX10
> +		BMC. This value is stored in flash and is mirrored
> +		in the MAX10 BMC register space.
> +		Format: "%u".
> diff --git a/drivers/mfd/intel-m10-bmc.c b/drivers/mfd/intel-m10-bmc.c
> index b84579b7b4f0..90720e84900e 100644
> --- a/drivers/mfd/intel-m10-bmc.c
> +++ b/drivers/mfd/intel-m10-bmc.c
> @@ -60,9 +60,52 @@ static ssize_t bmcfw_version_show(struct device *dev,
>  }
>  static DEVICE_ATTR_RO(bmcfw_version);
>  
> +static ssize_t mac_address_show(struct device *dev,
> +				struct device_attribute *attr, char *buf)
> +{
> +	struct intel_m10bmc *max10 = dev_get_drvdata(dev);
> +	unsigned int macaddr1, macaddr2;
> +	int ret;
> +
> +	ret = m10bmc_sys_read(max10, M10BMC_MACADDR1, &macaddr1);
> +	if (ret)
> +		return ret;
> +
> +	ret = m10bmc_sys_read(max10, M10BMC_MACADDR2, &macaddr2);
> +	if (ret)
> +		return ret;
> +

The mac_count implies there are more than 1 mac address.

This logic looks like could only do one.

How are the 2nd, 3rd  etc. mac addresses found ?

> +	return sprintf(buf, "%02x:%02x:%02x:%02x:%02x:%02x\n",
> +		       (u8)FIELD_GET(M10BMC_MAC_BYTE1, macaddr1),
> +		       (u8)FIELD_GET(M10BMC_MAC_BYTE2, macaddr1),
> +		       (u8)FIELD_GET(M10BMC_MAC_BYTE3, macaddr1),
> +		       (u8)FIELD_GET(M10BMC_MAC_BYTE4, macaddr1),
> +		       (u8)FIELD_GET(M10BMC_MAC_BYTE5, macaddr2),
> +		       (u8)FIELD_GET(M10BMC_MAC_BYTE6, macaddr2));

consider using sysfs_emit over sprintf

Tom

> +}
> +static DEVICE_ATTR_RO(mac_address);
> +
> +static ssize_t mac_count_show(struct device *dev,
> +			      struct device_attribute *attr, char *buf)
> +{
> +	struct intel_m10bmc *max10 = dev_get_drvdata(dev);
> +	unsigned int macaddr2;
> +	int ret;
> +
> +	ret = m10bmc_sys_read(max10, M10BMC_MACADDR2, &macaddr2);
> +	if (ret)
> +		return ret;
> +
> +	return sprintf(buf, "%u\n",
> +		       (u8)FIELD_GET(M10BMC_MAC_COUNT, macaddr2));
> +}
> +static DEVICE_ATTR_RO(mac_count);
> +
>  static struct attribute *m10bmc_attrs[] = {
>  	&dev_attr_bmc_version.attr,
>  	&dev_attr_bmcfw_version.attr,
> +	&dev_attr_mac_address.attr,
> +	&dev_attr_mac_count.attr,
>  	NULL,
>  };
>  ATTRIBUTE_GROUPS(m10bmc);
> diff --git a/include/linux/mfd/intel-m10-bmc.h b/include/linux/mfd/intel-m10-bmc.h
> index c8ef2f1654a4..2279e34f0814 100644
> --- a/include/linux/mfd/intel-m10-bmc.h
> +++ b/include/linux/mfd/intel-m10-bmc.h
> @@ -15,6 +15,15 @@
>  
>  /* Register offset of system registers */
>  #define NIOS2_FW_VERSION		0x0
> +#define M10BMC_MACADDR1			0x10
> +#define M10BMC_MAC_BYTE4		GENMASK(7, 0)
> +#define M10BMC_MAC_BYTE3		GENMASK(15, 8)
> +#define M10BMC_MAC_BYTE2		GENMASK(23, 16)
> +#define M10BMC_MAC_BYTE1		GENMASK(31, 24)
> +#define M10BMC_MACADDR2			0x14
> +#define M10BMC_MAC_BYTE6		GENMASK(7, 0)
> +#define M10BMC_MAC_BYTE5		GENMASK(15, 8)
> +#define M10BMC_MAC_COUNT		GENMASK(23, 16)
>  #define M10BMC_TEST_REG			0x3c
>  #define M10BMC_BUILD_VER		0x68
>  #define M10BMC_VER_MAJOR_MSK		GENMASK(23, 16)