memory: tegra20: Support interconnect framework

Now Internal and External Memory Controllers are memory interconnection
providers. This allows us to use interconnect API for tuning of memory
configuration. EMC driver now supports OPPs and DVFS.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20201104164923.21238-36-digetx@gmail.comSigned-off-by: Krzysztof Kozlowski <krzk@kernel.org>

drivers/memory/tegra/Kconfig

@@ -11,7 +11,8 @@ config TEGRA_MC
 config TEGRA20_EMC
 	tristate "NVIDIA Tegra20 External Memory Controller driver"
 	default y
-	depends on ARCH_TEGRA_2x_SOC
+	depends on TEGRA_MC && ARCH_TEGRA_2x_SOC
+	select PM_OPP
 	help
 	  This driver is for the External Memory Controller (EMC) found on
 	  Tegra20 chips. The EMC controls the external DRAM on the board.

drivers/memory/tegra/tegra20.c

@@ -3,6 +3,10 @@
  * Copyright (C) 2012 NVIDIA CORPORATION.  All rights reserved.
  */
 
+#include <linux/of_device.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+
 #include <dt-bindings/memory/tegra20-mc.h>
 
 #include "mc.h"
@@ -280,6 +284,78 @@ static const struct tegra_mc_reset_ops tegra20_mc_reset_ops = {
 	.reset_status = tegra20_mc_reset_status,
 };
 
+static int tegra20_mc_icc_set(struct icc_node *src, struct icc_node *dst)
+{
+	/*
+	 * It should be possible to tune arbitration knobs here, but the
+	 * default values are known to work well on all devices. Hence
+	 * nothing to do here so far.
+	 */
+	return 0;
+}
+
+static int tegra20_mc_icc_aggreate(struct icc_node *node, u32 tag, u32 avg_bw,
+				   u32 peak_bw, u32 *agg_avg, u32 *agg_peak)
+{
+	/*
+	 * ISO clients need to reserve extra bandwidth up-front because
+	 * there could be high bandwidth pressure during initial filling
+	 * of the client's FIFO buffers.  Secondly, we need to take into
+	 * account impurities of the memory subsystem.
+	 */
+	if (tag & TEGRA_MC_ICC_TAG_ISO)
+		peak_bw = tegra_mc_scale_percents(peak_bw, 300);
+
+	*agg_avg += avg_bw;
+	*agg_peak = max(*agg_peak, peak_bw);
+
+	return 0;
+}
+
+static struct icc_node_data *
+tegra20_mc_of_icc_xlate_extended(struct of_phandle_args *spec, void *data)
+{
+	struct tegra_mc *mc = icc_provider_to_tegra_mc(data);
+	unsigned int i, idx = spec->args[0];
+	struct icc_node_data *ndata;
+	struct icc_node *node;
+
+	list_for_each_entry(node, &mc->provider.nodes, node_list) {
+		if (node->id != idx)
+			continue;
+
+		ndata = kzalloc(sizeof(*ndata), GFP_KERNEL);
+		if (!ndata)
+			return ERR_PTR(-ENOMEM);
+
+		ndata->node = node;
+
+		/* these clients are isochronous by default */
+		if (strstarts(node->name, "display") ||
+		    strstarts(node->name, "vi"))
+			ndata->tag = TEGRA_MC_ICC_TAG_ISO;
+		else
+			ndata->tag = TEGRA_MC_ICC_TAG_DEFAULT;
+
+		return ndata;
+	}
+
+	for (i = 0; i < mc->soc->num_clients; i++) {
+		if (mc->soc->clients[i].id == idx)
+			return ERR_PTR(-EPROBE_DEFER);
+	}
+
+	dev_err(mc->dev, "invalid ICC client ID %u\n", idx);
+
+	return ERR_PTR(-EINVAL);
+}
+
+static const struct tegra_mc_icc_ops tegra20_mc_icc_ops = {
+	.xlate_extended = tegra20_mc_of_icc_xlate_extended,
+	.aggregate = tegra20_mc_icc_aggreate,
+	.set = tegra20_mc_icc_set,
+};
+
 const struct tegra_mc_soc tegra20_mc_soc = {
 	.clients = tegra20_mc_clients,
 	.num_clients = ARRAY_SIZE(tegra20_mc_clients),
@@ -290,4 +366,5 @@ const struct tegra_mc_soc tegra20_mc_soc = {
 	.reset_ops = &tegra20_mc_reset_ops,
 	.resets = tegra20_mc_resets,
 	.num_resets = ARRAY_SIZE(tegra20_mc_resets),
+	.icc_ops = &tegra20_mc_icc_ops,
 };