Re: [PATCH v3 1/1] mfd: intel-m10-bmc: expose mac address and count

[Russ Weight]

On 1/14/21 5:23 AM, Lee Jones wrote:
> On Tue, 05 Jan 2021, Russ Weight wrote:
>
>> Create two sysfs entries for exposing the MAC address
>> and count from the MAX10 BMC register space. The MAC
>> address is the first in a sequential block of MAC addresses
>> reserved for the FPGA card. The MAC count is the number
>> of MAC addresses in the reserved block.
>>
>> Signed-off-by: Russ Weight <russell.h.weight@xxxxxxxxx>
>> Signed-off-by: Xu Yilun <yilun.xu@xxxxxxxxx>
>> ---
>> v3:
>>   - Updated Date and KernelVersion in ABI documentation
>> v2:
>>   - Updated the documentation for the mac_address and mac_count
>>     sysfs nodes to clarify their usage.
>>   - Changed sysfs _show() functions to use sysfs_emit() instead
>>     of sprintf.
>> ---
>>  .../ABI/testing/sysfs-driver-intel-m10-bmc    | 21 +++++++++
>>  drivers/mfd/intel-m10-bmc.c                   | 43 +++++++++++++++++++
>>  include/linux/mfd/intel-m10-bmc.h             |  9 ++++
>>  3 files changed, 73 insertions(+)
>>
>> diff --git a/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc
>> index 979a2d62513f..9773925138af 100644
>> --- a/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc
>> +++ b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc
>> @@ -13,3 +13,24 @@ Contact:	Xu Yilun <yilun.xu@xxxxxxxxx>
>>  Description:	Read only. Returns the firmware version of Intel MAX10
>>  		BMC chip.
>>  		Format: "0x%x".
>> +
>> +What:		/sys/bus/spi/devices/.../mac_address
>> +Date:		January 2021
>> +KernelVersion:  5.12
>> +Contact:	Russ Weight <russell.h.weight@xxxxxxxxx>
>> +Description:	Read only. Returns the first MAC address in a block
>> +		of sequential MAC addresses assigned to the board
>> +		that is managed by the Intel MAX10 BMC. It is stored in
>> +		FLASH storage and is mirrored in the MAX10 BMC register
>> +		space.
>> +		Format: "%02x:%02x:%02x:%02x:%02x:%02x".
>> +
>> +What:		/sys/bus/spi/devices/.../mac_count
>> +Date:		January 2021
>> +KernelVersion:  5.12
>> +Contact:	Russ Weight <russell.h.weight@xxxxxxxxx>
>> +Description:	Read only. Returns the number of sequential 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..751c0ecf95d6 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;
> This naming convention is confusing.
>
> It took me a minute to work it out.
>
> Does 'high' and 'low' make sense!

Yes - that is more descriptive. I'll make the change and resubmit.

Thanks!
- Russ
>
>> +	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;
>> +
>> +	return sysfs_emit(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));
>> +}
>> +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 sysfs_emit(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)