memory: tegra: Add interconnect support for DRAM scaling in Tegra234

Add Interconnect framework support to dynamically set the DRAM
bandwidth from different clients. Both the MC and EMC drivers are
added as ICC providers. The path for any request is:
 MC-Client[1-n] -> MC -> EMC -> EMEM/DRAM

MC client's request for bandwidth will go to the MC driver which
passes the client request info like BPMP Client ID, Client type
and the Bandwidth to the BPMP-FW. The final DRAM freq to achieve
the requested bandwidth is set by the BPMP-FW based on the passed
parameters.

Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>

1 files changed, 133 insertions, 0 deletions

diff --git a/drivers/memory/tegra/tegra186-emc.c b/drivers/memory/tegra/tegra186-emc.c
index e935ad4e95b6..6ad8a4023dd7 100644
--- a/drivers/memory/tegra/tegra186-emc.c
+++ b/drivers/memory/tegra/tegra186-emc.c
@@ -7,9 +7,11 @@
 #include <linux/debugfs.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
+#include <linux/of_platform.h>
 #include <linux/platform_device.h>
 
 #include <soc/tegra/bpmp.h>
+#include "mc.h"
 
 struct tegra186_emc_dvfs {
 	unsigned long latency;
@@ -29,8 +31,15 @@ struct tegra186_emc {
 		unsigned long min_rate;
 		unsigned long max_rate;
 	} debugfs;
+
+	struct icc_provider provider;
 };
 
+static inline struct tegra186_emc *to_tegra186_emc(struct icc_provider *provider)
+{
+	return container_of(provider, struct tegra186_emc, provider);
+}
+
 /*
  * debugfs interface
  *
@@ -146,8 +155,102 @@ DEFINE_DEBUGFS_ATTRIBUTE(tegra186_emc_debug_max_rate_fops,
 			  tegra186_emc_debug_max_rate_get,
 			  tegra186_emc_debug_max_rate_set, "%llu\n");
 
+/*
+ * tegra_emc_icc_set_bw() - Set BW api for EMC provider
+ * @src: ICC node for External Memory Controller (EMC)
+ * @dst: ICC node for External Memory (DRAM)
+ *
+ * Do nothing here as info to BPMP-FW is now passed in the BW set function
+ * of the MC driver. BPMP-FW sets the final Freq based on the passed values.
+ */
+static int tegra_emc_icc_set_bw(struct icc_node *src, struct icc_node *dst)
+{
+	return 0;
+}
+
+static struct icc_node *
+tegra_emc_of_icc_xlate(struct of_phandle_args *spec, void *data)
+{
+	struct icc_provider *provider = data;
+	struct icc_node *node;
+
+	/* External Memory is the only possible ICC route */
+	list_for_each_entry(node, &provider->nodes, node_list) {
+		if (node->id != TEGRA_ICC_EMEM)
+			continue;
+
+		return node;
+	}
+
+	return ERR_PTR(-EPROBE_DEFER);
+}
+
+static int tegra_emc_icc_get_init_bw(struct icc_node *node, u32 *avg, u32 *peak)
+{
+	*avg = 0;
+	*peak = 0;
+
+	return 0;
+}
+
+static int tegra_emc_interconnect_init(struct tegra186_emc *emc)
+{
+	struct tegra_mc *mc = dev_get_drvdata(emc->dev->parent);
+	const struct tegra_mc_soc *soc = mc->soc;
+	struct icc_node *node;
+	int err;
+
+	emc->provider.dev = emc->dev;
+	emc->provider.set = tegra_emc_icc_set_bw;
+	emc->provider.data = &emc->provider;
+	emc->provider.aggregate = soc->icc_ops->aggregate;
+	emc->provider.xlate = tegra_emc_of_icc_xlate;
+	emc->provider.get_bw = tegra_emc_icc_get_init_bw;
+
+	icc_provider_init(&emc->provider);
+
+	/* create External Memory Controller node */
+	node = icc_node_create(TEGRA_ICC_EMC);
+	if (IS_ERR(node)) {
+		err = PTR_ERR(node);
+		goto err_msg;
+	}
+
+	node->name = "External Memory Controller";
+	icc_node_add(node, &emc->provider);
+
+	/* link External Memory Controller to External Memory (DRAM) */
+	err = icc_link_create(node, TEGRA_ICC_EMEM);
+	if (err)
+		goto remove_nodes;
+
+	/* create External Memory node */
+	node = icc_node_create(TEGRA_ICC_EMEM);
+	if (IS_ERR(node)) {
+		err = PTR_ERR(node);
+		goto remove_nodes;
+	}
+
+	node->name = "External Memory (DRAM)";
+	icc_node_add(node, &emc->provider);
+
+	err = icc_provider_register(&emc->provider);
+	if (err)
+		goto remove_nodes;
+
+	return 0;
+
+remove_nodes:
+	icc_nodes_remove(&emc->provider);
+err_msg:
+	dev_err(emc->dev, "failed to initialize ICC: %d\n", err);
+
+	return err;
+}
+
 static int tegra186_emc_probe(struct platform_device *pdev)
 {
+	struct tegra_mc *mc = dev_get_drvdata(pdev->dev.parent);
 	struct mrq_emc_dvfs_latency_response response;
 	struct tegra_bpmp_message msg;
 	struct tegra186_emc *emc;
@@ -236,6 +339,32 @@ static int tegra186_emc_probe(struct platform_device *pdev)
 	debugfs_create_file("max_rate", S_IRUGO | S_IWUSR, emc->debugfs.root,
 			    emc, &tegra186_emc_debug_max_rate_fops);
 
+	if (mc && mc->soc->icc_ops) {
+		if (tegra_bpmp_mrq_is_supported(emc->bpmp, MRQ_BWMGR_INT)) {
+			mc->bwmgr_mrq_supported = true;
+
+			/*
+			 * MC driver probe can't get BPMP reference as it gets probed
+			 * earlier than BPMP. So, save the BPMP ref got from the EMC
+			 * DT node in the mc->bpmp and use it in MC's icc_set hook.
+			 */
+			mc->bpmp = emc->bpmp;
+			barrier();
+		}
+
+		/*
+		 * Initialize the ICC even if BPMP-FW doesn't support 'MRQ_BWMGR_INT'.
+		 * Use the flag 'mc->bwmgr_mrq_supported' within MC driver and return
+		 * EINVAL instead of passing the request to BPMP-FW later when the BW
+		 * request is made by client with 'icc_set_bw()' call.
+		 */
+		err = tegra_emc_interconnect_init(emc);
+		if (err) {
+			mc->bpmp = NULL;
+			goto put_bpmp;
+		}
+	}
+
 	return 0;
 
 put_bpmp:
@@ -245,9 +374,12 @@ put_bpmp:
 
 static int tegra186_emc_remove(struct platform_device *pdev)
 {
+	struct tegra_mc *mc = dev_get_drvdata(pdev->dev.parent);
 	struct tegra186_emc *emc = platform_get_drvdata(pdev);
 
 	debugfs_remove_recursive(emc->debugfs.root);
+
+	mc->bpmp = NULL;
 	tegra_bpmp_put(emc->bpmp);
 
 	return 0;
@@ -272,6 +404,7 @@ static struct platform_driver tegra186_emc_driver = {
 		.name = "tegra186-emc",
 		.of_match_table = tegra186_emc_of_match,
 		.suppress_bind_attrs = true,
+		.sync_state = icc_sync_state,
 	},
 	.probe = tegra186_emc_probe,
 	.remove = tegra186_emc_remove,