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

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Message-ID: <6783078e-2dc4-e261-61d6-148cb4f0e848@intel.com>
Date:   Wed, 2 Dec 2020 10:26:40 -0800
From:   Russ Weight <russell.h.weight@...el.com>
To:     Tom Rix <trix@...hat.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 12/2/20 5:44 AM, Tom Rix wrote:
> 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 ?
The MAC addresses assigned to the card are sequential. The base MAC
address is exposed through the mac_address sysfs entry. Add 1 to
that MAC address for the second MAC address, etc.
>
>> +	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
Yes. I'll change to sysfs_emit and resubmit.

Thanks,
- Russ
>
> 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)