[PATCH 11/33] arm_mpam: Add support for memory controller MSC on DT platforms

[James Morse]

Hi Shaopeng,

On 09/09/2025 08:11, Shaopeng Tan (Fujitsu) wrote:
>> From: Shanker Donthineni <sdonthineni at nvidia.com>
>>
>> The device-tree binding has two examples for MSC associated with memory
>> controllers. Add the support to discover the component_id from the device-tree
>> and create 'memory' RIS.

>> diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
>> index a0d9a699a6e7..71a1fb1a9c75 100644
>> --- a/drivers/resctrl/mpam_devices.c
>> +++ b/drivers/resctrl/mpam_devices.c
>> @@ -62,41 +62,63 @@ static int mpam_dt_parse_resource(struct mpam_msc
>> *msc, struct device_node *np,
>>  				  u32 ris_idx)
>>  {
>>  	int err = 0;
>> -	u32 level = 0;
>> -	unsigned long cache_id;
>> -	struct device_node *cache;
>> +	u32 class_id = 0, component_id = 0;
>> +	struct device_node *cache = NULL, *memory = NULL;
>> +	enum mpam_class_types type = MPAM_CLASS_UNKNOWN;
>>
>>  	do {
>> +		/* What kind of MSC is this? */
>>  		if (of_device_is_compatible(np, "arm,mpam-cache")) {
>>  			cache = of_parse_phandle(np, "arm,mpam-device",
>> 0);
>>  			if (!cache) {
>>  				pr_err("Failed to read phandle\n");
>>  				break;
>>  			}
>> +			type = MPAM_CLASS_CACHE;
>>  		} else if (of_device_is_compatible(np->parent, "cache")) {
>>  			cache = of_node_get(np->parent);
>> +			type = MPAM_CLASS_CACHE;
>> +		} else if (of_device_is_compatible(np, "arm,mpam-memory"))
>> {
>> +			memory = of_parse_phandle(np, "arm,mpam-device",
>> 0);
>> +			if (!memory) {
>> +				pr_err("Failed to read phandle\n");
>> +				break;
>> +			}
>> +			type = MPAM_CLASS_MEMORY;
>> +		} else if (of_device_is_compatible(np,
>> "arm,mpam-memory-controller-msc")) {
>> +			memory = of_node_get(np->parent);
>> +			type = MPAM_CLASS_MEMORY;
>>  		} else {
>> -			/* For now, only caches are supported */
>> -			cache = NULL;
>> +			/*
>> +			 * For now, only caches and memory controllers are
>> +			 * supported.
>> +			 */
>>  			break;
>>  		}

> There is no need "{}" here.

Sure, but its more than one line, and all the previous parts of this else-if tree have
them. Keeping this here make it much easier to read.


Thanks,

James