Re: [PATCH V7 2/5] interconnect: qcom: Add multidev EPSS L3 support

[Raviteja Laggyshetty <quic_rlaggysh@quicinc.com>]

On 1/12/2025 2:38 AM, Bjorn Andersson wrote:
> On Sat, Jan 11, 2025 at 04:14:26PM +0000, Raviteja Laggyshetty wrote:
>> EPSS on SA8775P has two instances which requires creation of two device
>> nodes with different compatible and device data because of unique
>> icc node id and name limitation in interconnect framework.
>> Add multidevice support to osm-l3 code to get unique node id from icc
>> framework.
>>
>> Signed-off-by: Raviteja Laggyshetty <quic_rlaggysh@quicinc.com>
>> ---
>>  drivers/interconnect/qcom/osm-l3.c | 91 ++++++++++++++++++++++--------
>>  1 file changed, 67 insertions(+), 24 deletions(-)
>>
>> diff --git a/drivers/interconnect/qcom/osm-l3.c b/drivers/interconnect/qcom/osm-l3.c
>> index 6a656ed44d49..8e98d1c9a840 100644
>> --- a/drivers/interconnect/qcom/osm-l3.c
>> +++ b/drivers/interconnect/qcom/osm-l3.c
>> @@ -1,6 +1,7 @@
>>  // SPDX-License-Identifier: GPL-2.0
>>  /*
>>   * Copyright (c) 2020-2021, The Linux Foundation. All rights reserved.
>> + * Copyright (c) 2025 Qualcomm Innovation Center, Inc. All rights reserved.
>>   */
>>  
>>  #include <linux/args.h>
>> @@ -11,6 +12,7 @@
>>  #include <linux/kernel.h>
>>  #include <linux/module.h>
>>  #include <linux/of.h>
>> +#include <linux/of_address.h>
>>  #include <linux/platform_device.h>
>>  
>>  #include <dt-bindings/interconnect/qcom,osm-l3.h>
>> @@ -34,6 +36,9 @@
>>  
>>  #define OSM_L3_MAX_LINKS		1
>>  
>> +#define OSM_L3_NODE_ID_START		10000
>> +#define OSM_NODE_NAME_SUFFIX_SIZE	10
>> +
>>  #define to_osm_l3_provider(_provider) \
>>  	container_of(_provider, struct qcom_osm_l3_icc_provider, provider)
>>  
>> @@ -55,46 +60,40 @@ struct qcom_osm_l3_icc_provider {
>>   */
>>  struct qcom_osm_l3_node {
>>  	const char *name;
>> -	u16 links[OSM_L3_MAX_LINKS];
>> +	const char *links[OSM_L3_MAX_LINKS];
>>  	u16 id;
>>  	u16 num_links;
>>  	u16 buswidth;
>>  };
>>  
>>  struct qcom_osm_l3_desc {
>> -	const struct qcom_osm_l3_node * const *nodes;
>> +	struct qcom_osm_l3_node * const *nodes;
>>  	size_t num_nodes;
>>  	unsigned int lut_row_size;
>>  	unsigned int reg_freq_lut;
>>  	unsigned int reg_perf_state;
>>  };
>>  
>> -enum {
>> -	OSM_L3_MASTER_NODE = 10000,
>> -	OSM_L3_SLAVE_NODE,
>> -};
>> -
>> -#define DEFINE_QNODE(_name, _id, _buswidth, ...)			\
>> -	static const struct qcom_osm_l3_node _name = {			\
>> +#define DEFINE_QNODE(_name, _buswidth, ...)				\
>> +	static struct qcom_osm_l3_node _name = {			\
>>  		.name = #_name,						\
>> -		.id = _id,						\
>>  		.buswidth = _buswidth,					\
>>  		.num_links = COUNT_ARGS(__VA_ARGS__),			\
>> -		.links = { __VA_ARGS__ },				\
>> +		__VA_OPT__(.links = { #__VA_ARGS__ })			\
>>  	}
>>  
>> -DEFINE_QNODE(osm_l3_master, OSM_L3_MASTER_NODE, 16, OSM_L3_SLAVE_NODE);
>> -DEFINE_QNODE(osm_l3_slave, OSM_L3_SLAVE_NODE, 16);
>> +DEFINE_QNODE(osm_l3_master, 16, osm_l3_slave);
>> +DEFINE_QNODE(osm_l3_slave, 16);
>>  
>> -static const struct qcom_osm_l3_node * const osm_l3_nodes[] = {
>> +static struct qcom_osm_l3_node * const osm_l3_nodes[] = {
>>  	[MASTER_OSM_L3_APPS] = &osm_l3_master,
>>  	[SLAVE_OSM_L3] = &osm_l3_slave,
>>  };
>>  
>> -DEFINE_QNODE(epss_l3_master, OSM_L3_MASTER_NODE, 32, OSM_L3_SLAVE_NODE);
>> -DEFINE_QNODE(epss_l3_slave, OSM_L3_SLAVE_NODE, 32);
>> +DEFINE_QNODE(epss_l3_master, 32, epss_l3_slave);
>> +DEFINE_QNODE(epss_l3_slave, 32);
>>  
>> -static const struct qcom_osm_l3_node * const epss_l3_nodes[] = {
>> +static struct qcom_osm_l3_node * const epss_l3_nodes[] = {
>>  	[MASTER_EPSS_L3_APPS] = &epss_l3_master,
>>  	[SLAVE_EPSS_L3_SHARED] = &epss_l3_slave,
>>  };
>> @@ -123,6 +122,19 @@ static const struct qcom_osm_l3_desc epss_l3_l3_vote = {
>>  	.reg_perf_state = EPSS_REG_L3_VOTE,
>>  };
>>  
>> +static u16 get_node_id_by_name(const char *node_name,
>> +			       const struct qcom_osm_l3_desc *desc)
>> +{
>> +	struct qcom_osm_l3_node *const *nodes = desc->nodes;
>> +	int i;
>> +
>> +	for (i = 0; i < desc->num_nodes; i++) {
>> +		if (!strcmp(nodes[i]->name, node_name))
>> +			return nodes[i]->id;
>> +	}
>> +	return 0;
>> +}
>> +
>>  static int qcom_osm_l3_set(struct icc_node *src, struct icc_node *dst)
>>  {
>>  	struct qcom_osm_l3_icc_provider *qp;
>> @@ -164,10 +176,11 @@ static int qcom_osm_l3_probe(struct platform_device *pdev)
>>  	const struct qcom_osm_l3_desc *desc;
>>  	struct icc_onecell_data *data;
>>  	struct icc_provider *provider;
>> -	const struct qcom_osm_l3_node * const *qnodes;
>> +	struct qcom_osm_l3_node * const *qnodes;
>>  	struct icc_node *node;
>>  	size_t num_nodes;
>>  	struct clk *clk;
>> +	u64 addr;
>>  	int ret;
>>  
>>  	clk = clk_get(&pdev->dev, "xo");
>> @@ -188,6 +201,10 @@ static int qcom_osm_l3_probe(struct platform_device *pdev)
>>  	if (!qp)
>>  		return -ENOMEM;
>>  
>> +	ret = of_property_read_reg(pdev->dev.of_node, 0, &addr, NULL);
>> +	if (ret)
>> +		return ret;
>> +
>>  	qp->base = devm_platform_ioremap_resource(pdev, 0);
>>  	if (IS_ERR(qp->base))
>>  		return PTR_ERR(qp->base);
>> @@ -242,26 +259,51 @@ static int qcom_osm_l3_probe(struct platform_device *pdev)
>>  
>>  	icc_provider_init(provider);
>>  
>> +	/* create icc nodes */
>>  	for (i = 0; i < num_nodes; i++) {
>> -		size_t j;
>> +		char *node_name;
>> +		size_t len;
>>  
>> -		node = icc_node_create(qnodes[i]->id);
>> +		node = icc_node_create_alloc_id(OSM_L3_NODE_ID_START);
>>  		if (IS_ERR(node)) {
>>  			ret = PTR_ERR(node);
>>  			goto err;
>>  		}
>> +		qnodes[i]->id = node->id;
>> +
>> +		/* len = strlen(node->name) + @ + 8 (base-address) + NULL */
>> +		len = strlen(qnodes[i]->name) + OSM_NODE_NAME_SUFFIX_SIZE;
>> +		node_name = devm_kzalloc(&pdev->dev, len, GFP_KERNEL);
>> +		if (!node_name) {
>> +			ret = -ENOMEM;
>> +			goto err;
>> +		}
>> +
>> +		snprintf(node_name, len, "%s@%08llx", qnodes[i]->name, addr);
>> +		node->name = node_name;
> 
> I don't think it's reasonable to duplicate this logic and the decision
> of naming convention in each provider driver. Please provide a generic
> solution in the framework.
> 
I will be moving the logic to framework.
> 
> PS. Not that I want you to use it here, but for the next time be aware
> of devm_kasprintf().
> 
Will make use of devm_kasprintf in the next patch revision.
>>  
>> -		node->name = qnodes[i]->name;
>>  		/* Cast away const and add it back in qcom_osm_l3_set() */
>>  		node->data = (void *)qnodes[i];
>>  		icc_node_add(node, provider);
>>  
>> -		for (j = 0; j < qnodes[i]->num_links; j++)
>> -			icc_link_create(node, qnodes[i]->links[j]);
>> -
>>  		data->nodes[i] = node;
>>  	}
>>  
>> +	/* create links in topolgy */
>> +	for (i = 0; i < num_nodes; i++) {
>> +		size_t j;
>> +
>> +		node = data->nodes[i];
>> +		for (j = 0; j < qnodes[i]->num_links; j++) {
>> +			u16 link_node_id = get_node_id_by_name(qnodes[i]->links[j], desc);
> 
> Isn't that O(i^2*j) string comparisons? I don't find that acceptable.

Agreed, I will be linking the nodes using pointers instead of strings,
this will avoid additional loops and lookups while creating the links.

> 
>> +
>> +			if (link_node_id)
>> +				icc_link_create(node, link_node_id);
>> +			else
>> +				goto err;
>> +		}
>> +	}
>> +
>>  	ret = icc_provider_register(provider);
>>  	if (ret)
>>  		goto err;
>> @@ -284,6 +326,7 @@ static const struct of_device_id osm_l3_of_match[] = {
>>  	{ .compatible = "qcom,sm8150-osm-l3", .data = &osm_l3 },
>>  	{ .compatible = "qcom,sc8180x-osm-l3", .data = &osm_l3 },
>>  	{ .compatible = "qcom,sm8250-epss-l3", .data = &epss_l3_perf_state },
>> +	{ .compatible = "qcom,sa8775p-epss-l3", .data = &epss_l3_perf_state },
> 
> With the exception of sc8180x, this list is sorted alphabetically.
> Please insert your entry where it makes sense.
> 
Sure, I will fix it in next patch series.

> Regards,
> Bjorn
> 
>>  	{ }
>>  };
>>  MODULE_DEVICE_TABLE(of, osm_l3_of_match);
>> -- 
>> 2.39.2
>>