[PATCH v12 3/5] memory: tegra124: Support interconnect framework

[Dmitry Osipenko <digetx@gmail.com>]

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.

Tested-by: Nicolas Chauvet <kwizart@gmail.com>
Acked-by: Georgi Djakov <georgi.djakov@linaro.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/memory/tegra/Kconfig        |   1 +
 drivers/memory/tegra/tegra124-emc.c | 320 +++++++++++++++++++++++++++-
 drivers/memory/tegra/tegra124.c     |  82 ++++++-
 3 files changed, 391 insertions(+), 12 deletions(-)

diff --git a/drivers/memory/tegra/Kconfig b/drivers/memory/tegra/Kconfig
index f5b451403c58..a70967a56e52 100644
--- a/drivers/memory/tegra/Kconfig
+++ b/drivers/memory/tegra/Kconfig
@@ -36,6 +36,7 @@ config TEGRA124_EMC
 	default y
 	depends on TEGRA_MC && ARCH_TEGRA_124_SOC
 	select TEGRA124_CLK_EMC
+	select PM_OPP
 	help
 	  This driver is for the External Memory Controller (EMC) found on
 	  Tegra124 chips. The EMC controls the external DRAM on the board.
diff --git a/drivers/memory/tegra/tegra124-emc.c b/drivers/memory/tegra/tegra124-emc.c
index 8fb8c1af25c9..9706550bdd5d 100644
--- a/drivers/memory/tegra/tegra124-emc.c
+++ b/drivers/memory/tegra/tegra124-emc.c
@@ -12,20 +12,26 @@
 #include <linux/clk/tegra.h>
 #include <linux/debugfs.h>
 #include <linux/delay.h>
+#include <linux/interconnect-provider.h>
 #include <linux/io.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/of_address.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
+#include <linux/pm_opp.h>
 #include <linux/sort.h>
 #include <linux/string.h>
 
 #include <soc/tegra/fuse.h>
 #include <soc/tegra/mc.h>
 
+#include "mc.h"
+
 #define EMC_FBIO_CFG5				0x104
 #define	EMC_FBIO_CFG5_DRAM_TYPE_MASK		0x3
 #define	EMC_FBIO_CFG5_DRAM_TYPE_SHIFT		0
+#define EMC_FBIO_CFG5_DRAM_WIDTH_X64		BIT(4)
 
 #define EMC_INTSTATUS				0x0
 #define EMC_INTSTATUS_CLKCHANGE_COMPLETE	BIT(4)
@@ -461,6 +467,17 @@ struct emc_timing {
 	u32 emc_zcal_interval;
 };
 
+enum emc_rate_request_type {
+	EMC_RATE_DEBUG,
+	EMC_RATE_ICC,
+	EMC_RATE_TYPE_MAX,
+};
+
+struct emc_rate_request {
+	unsigned long min_rate;
+	unsigned long max_rate;
+};
+
 struct tegra_emc {
 	struct device *dev;
 
@@ -471,6 +488,7 @@ struct tegra_emc {
 	struct clk *clk;
 
 	enum emc_dram_type dram_type;
+	unsigned int dram_bus_width;
 	unsigned int dram_num;
 
 	struct emc_timing last_timing;
@@ -482,6 +500,17 @@ struct tegra_emc {
 		unsigned long min_rate;
 		unsigned long max_rate;
 	} debugfs;
+
+	struct icc_provider provider;
+
+	/*
+	 * There are multiple sources in the EMC driver which could request
+	 * a min/max clock rate, these rates are contained in this array.
+	 */
+	struct emc_rate_request requested_rate[EMC_RATE_TYPE_MAX];
+
+	/* protect shared rate-change code path */
+	struct mutex rate_lock;
 };
 
 /* Timing change sequence functions */
@@ -870,6 +899,14 @@ static void emc_read_current_timing(struct tegra_emc *emc,
 static int emc_init(struct tegra_emc *emc)
 {
 	emc->dram_type = readl(emc->regs + EMC_FBIO_CFG5);
+
+	if (emc->dram_type & EMC_FBIO_CFG5_DRAM_WIDTH_X64)
+		emc->dram_bus_width = 64;
+	else
+		emc->dram_bus_width = 32;
+
+	dev_info(emc->dev, "%ubit DRAM bus\n", emc->dram_bus_width);
+
 	emc->dram_type &= EMC_FBIO_CFG5_DRAM_TYPE_MASK;
 	emc->dram_type >>= EMC_FBIO_CFG5_DRAM_TYPE_SHIFT;
 
@@ -1009,6 +1046,83 @@ tegra_emc_find_node_by_ram_code(struct device_node *node, u32 ram_code)
 	return NULL;
 }
 
+static void tegra_emc_rate_requests_init(struct tegra_emc *emc)
+{
+	unsigned int i;
+
+	for (i = 0; i < EMC_RATE_TYPE_MAX; i++) {
+		emc->requested_rate[i].min_rate = 0;
+		emc->requested_rate[i].max_rate = ULONG_MAX;
+	}
+}
+
+static int emc_request_rate(struct tegra_emc *emc,
+			    unsigned long new_min_rate,
+			    unsigned long new_max_rate,
+			    enum emc_rate_request_type type)
+{
+	struct emc_rate_request *req = emc->requested_rate;
+	unsigned long min_rate = 0, max_rate = ULONG_MAX;
+	unsigned int i;
+	int err;
+
+	/* select minimum and maximum rates among the requested rates */
+	for (i = 0; i < EMC_RATE_TYPE_MAX; i++, req++) {
+		if (i == type) {
+			min_rate = max(new_min_rate, min_rate);
+			max_rate = min(new_max_rate, max_rate);
+		} else {
+			min_rate = max(req->min_rate, min_rate);
+			max_rate = min(req->max_rate, max_rate);
+		}
+	}
+
+	if (min_rate > max_rate) {
+		dev_err_ratelimited(emc->dev, "%s: type %u: out of range: %lu %lu\n",
+				    __func__, type, min_rate, max_rate);
+		return -ERANGE;
+	}
+
+	/*
+	 * EMC rate-changes should go via OPP API because it manages voltage
+	 * changes.
+	 */
+	err = dev_pm_opp_set_rate(emc->dev, min_rate);
+	if (err)
+		return err;
+
+	emc->requested_rate[type].min_rate = new_min_rate;
+	emc->requested_rate[type].max_rate = new_max_rate;
+
+	return 0;
+}
+
+static int emc_set_min_rate(struct tegra_emc *emc, unsigned long rate,
+			    enum emc_rate_request_type type)
+{
+	struct emc_rate_request *req = &emc->requested_rate[type];
+	int ret;
+
+	mutex_lock(&emc->rate_lock);
+	ret = emc_request_rate(emc, rate, req->max_rate, type);
+	mutex_unlock(&emc->rate_lock);
+
+	return ret;
+}
+
+static int emc_set_max_rate(struct tegra_emc *emc, unsigned long rate,
+			    enum emc_rate_request_type type)
+{
+	struct emc_rate_request *req = &emc->requested_rate[type];
+	int ret;
+
+	mutex_lock(&emc->rate_lock);
+	ret = emc_request_rate(emc, req->min_rate, rate, type);
+	mutex_unlock(&emc->rate_lock);
+
+	return ret;
+}
+
 /*
  * debugfs interface
  *
@@ -1081,7 +1195,7 @@ static int tegra_emc_debug_min_rate_set(void *data, u64 rate)
 	if (!tegra_emc_validate_rate(emc, rate))
 		return -EINVAL;
 
-	err = clk_set_min_rate(emc->clk, rate);
+	err = emc_set_min_rate(emc, rate, EMC_RATE_DEBUG);
 	if (err < 0)
 		return err;
 
@@ -1111,7 +1225,7 @@ static int tegra_emc_debug_max_rate_set(void *data, u64 rate)
 	if (!tegra_emc_validate_rate(emc, rate))
 		return -EINVAL;
 
-	err = clk_set_max_rate(emc->clk, rate);
+	err = emc_set_max_rate(emc, rate, EMC_RATE_DEBUG);
 	if (err < 0)
 		return err;
 
@@ -1129,15 +1243,6 @@ static void emc_debugfs_init(struct device *dev, struct tegra_emc *emc)
 	unsigned int i;
 	int err;
 
-	emc->clk = devm_clk_get(dev, "emc");
-	if (IS_ERR(emc->clk)) {
-		if (PTR_ERR(emc->clk) != -ENODEV) {
-			dev_err(dev, "failed to get EMC clock: %ld\n",
-				PTR_ERR(emc->clk));
-			return;
-		}
-	}
-
 	emc->debugfs.min_rate = ULONG_MAX;
 	emc->debugfs.max_rate = 0;
 
@@ -1177,6 +1282,177 @@ static void emc_debugfs_init(struct device *dev, struct tegra_emc *emc)
 			    emc, &tegra_emc_debug_max_rate_fops);
 }
 
+static inline struct tegra_emc *
+to_tegra_emc_provider(struct icc_provider *provider)
+{
+	return container_of(provider, struct tegra_emc, provider);
+}
+
+static struct icc_node_data *
+emc_of_icc_xlate_extended(struct of_phandle_args *spec, void *data)
+{
+	struct icc_provider *provider = data;
+	struct icc_node_data *ndata;
+	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;
+
+		ndata = kzalloc(sizeof(*ndata), GFP_KERNEL);
+		if (!ndata)
+			return ERR_PTR(-ENOMEM);
+
+		/*
+		 * SRC and DST nodes should have matching TAG in order to have
+		 * it set by default for a requested path.
+		 */
+		ndata->tag = TEGRA_MC_ICC_TAG_ISO;
+		ndata->node = node;
+
+		return ndata;
+	}
+
+	return ERR_PTR(-EPROBE_DEFER);
+}
+
+static int emc_icc_set(struct icc_node *src, struct icc_node *dst)
+{
+	struct tegra_emc *emc = to_tegra_emc_provider(dst->provider);
+	unsigned long long peak_bw = icc_units_to_bps(dst->peak_bw);
+	unsigned long long avg_bw = icc_units_to_bps(dst->avg_bw);
+	unsigned long long rate = max(avg_bw, peak_bw);
+	unsigned int dram_data_bus_width_bytes;
+	const unsigned int ddr = 2;
+	int err;
+
+	/*
+	 * Tegra124 EMC runs on a clock rate of SDRAM bus. This means that
+	 * EMC clock rate is twice smaller than the peak data rate because
+	 * data is sampled on both EMC clock edges.
+	 */
+	dram_data_bus_width_bytes = emc->dram_bus_width / 8;
+	do_div(rate, ddr * dram_data_bus_width_bytes);
+	rate = min_t(u64, rate, U32_MAX);
+
+	err = emc_set_min_rate(emc, rate, EMC_RATE_ICC);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static int tegra_emc_interconnect_init(struct tegra_emc *emc)
+{
+	const struct tegra_mc_soc *soc = emc->mc->soc;
+	struct icc_node *node;
+	int err;
+
+	emc->provider.dev = emc->dev;
+	emc->provider.set = emc_icc_set;
+	emc->provider.data = &emc->provider;
+	emc->provider.aggregate = soc->icc_ops->aggregate;
+	emc->provider.xlate_extended = emc_of_icc_xlate_extended;
+
+	err = icc_provider_add(&emc->provider);
+	if (err)
+		goto err_msg;
+
+	/* create External Memory Controller node */
+	node = icc_node_create(TEGRA_ICC_EMC);
+	if (IS_ERR(node)) {
+		err = PTR_ERR(node);
+		goto del_provider;
+	}
+
+	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);
+
+	return 0;
+
+remove_nodes:
+	icc_nodes_remove(&emc->provider);
+del_provider:
+	icc_provider_del(&emc->provider);
+err_msg:
+	dev_err(emc->dev, "failed to initialize ICC: %d\n", err);
+
+	return err;
+}
+
+static int tegra_emc_opp_table_init(struct tegra_emc *emc)
+{
+	u32 hw_version = BIT(tegra_sku_info.soc_speedo_id);
+	struct opp_table *clk_opp_table, *hw_opp_table;
+	int err;
+
+	clk_opp_table = dev_pm_opp_set_clkname(emc->dev, NULL);
+	err = PTR_ERR_OR_ZERO(clk_opp_table);
+	if (err) {
+		dev_err(emc->dev, "failed to set OPP clk: %d\n", err);
+		return err;
+	}
+
+	hw_opp_table = dev_pm_opp_set_supported_hw(emc->dev, &hw_version, 1);
+	err = PTR_ERR_OR_ZERO(hw_opp_table);
+	if (err) {
+		dev_err(emc->dev, "failed to set OPP supported HW: %d\n", err);
+		goto put_clk_table;
+	}
+
+	err = dev_pm_opp_of_add_table(emc->dev);
+	if (err) {
+		if (err == -ENODEV)
+			dev_err(emc->dev, "OPP table not found, please update your device tree\n");
+		else
+			dev_err(emc->dev, "failed to add OPP table: %d\n", err);
+
+		goto put_hw_table;
+	}
+
+	dev_info(emc->dev, "OPP HW ver. 0x%x, current clock rate %lu MHz\n",
+		 hw_version, clk_get_rate(emc->clk) / 1000000);
+
+	/* first dummy rate-set initializes voltage state */
+	err = dev_pm_opp_set_rate(emc->dev, clk_get_rate(emc->clk));
+	if (err) {
+		dev_err(emc->dev, "failed to initialize OPP clock: %d\n", err);
+		goto remove_table;
+	}
+
+	return 0;
+
+remove_table:
+	dev_pm_opp_of_remove_table(emc->dev);
+put_hw_table:
+	dev_pm_opp_put_supported_hw(hw_opp_table);
+put_clk_table:
+	dev_pm_opp_put_clkname(clk_opp_table);
+
+	return err;
+}
+
+static void devm_tegra_emc_unset_callback(void *data)
+{
+	tegra124_clk_set_emc_callbacks(NULL, NULL);
+}
+
 static int tegra_emc_probe(struct platform_device *pdev)
 {
 	struct device_node *np;
@@ -1188,6 +1464,7 @@ static int tegra_emc_probe(struct platform_device *pdev)
 	if (!emc)
 		return -ENOMEM;
 
+	mutex_init(&emc->rate_lock);
 	emc->dev = &pdev->dev;
 
 	emc->regs = devm_platform_ioremap_resource(pdev, 0);
@@ -1223,9 +1500,29 @@ static int tegra_emc_probe(struct platform_device *pdev)
 	tegra124_clk_set_emc_callbacks(tegra_emc_prepare_timing_change,
 				       tegra_emc_complete_timing_change);
 
+	err = devm_add_action_or_reset(&pdev->dev, devm_tegra_emc_unset_callback,
+				       NULL);
+	if (err)
+		return err;
+
+	emc->clk = devm_clk_get(&pdev->dev, "emc");
+	if (IS_ERR(emc->clk)) {
+		err = PTR_ERR(emc->clk);
+		dev_err(&pdev->dev, "failed to get EMC clock: %d\n", err);
+		return err;
+	}
+
+	err = tegra_emc_opp_table_init(emc);
+	if (err)
+		return err;
+
+	tegra_emc_rate_requests_init(emc);
+
 	if (IS_ENABLED(CONFIG_DEBUG_FS))
 		emc_debugfs_init(&pdev->dev, emc);
 
+	tegra_emc_interconnect_init(emc);
+
 	/*
 	 * Don't allow the kernel module to be unloaded. Unloading adds some
 	 * extra complexity which doesn't really worth the effort in a case of
@@ -1242,6 +1539,7 @@ static struct platform_driver tegra_emc_driver = {
 		.name = "tegra-emc",
 		.of_match_table = tegra_emc_of_match,
 		.suppress_bind_attrs = true,
+		.sync_state = icc_sync_state,
 	},
 };
 module_platform_driver(tegra_emc_driver);
diff --git a/drivers/memory/tegra/tegra124.c b/drivers/memory/tegra/tegra124.c
index e2389573d3c0..459211f50c08 100644
--- a/drivers/memory/tegra/tegra124.c
+++ b/drivers/memory/tegra/tegra124.c
@@ -4,7 +4,8 @@
  */
 
 #include <linux/of.h>
-#include <linux/mm.h>
+#include <linux/of_device.h>
+#include <linux/slab.h>
 
 #include <dt-bindings/memory/tegra124-mc.h>
 
@@ -1010,6 +1011,83 @@ static const struct tegra_mc_reset tegra124_mc_resets[] = {
 	TEGRA124_MC_RESET(GPU,       0x970, 0x974,  2),
 };
 
+static int tegra124_mc_icc_set(struct icc_node *src, struct icc_node *dst)
+{
+	/* TODO: program PTSA */
+	return 0;
+}
+
+static int tegra124_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, 400);
+
+	*agg_avg += avg_bw;
+	*agg_peak = max(*agg_peak, peak_bw);
+
+	return 0;
+}
+
+static struct icc_node_data *
+tegra124_mc_of_icc_xlate_extended(struct of_phandle_args *spec, void *data)
+{
+	struct tegra_mc *mc = icc_provider_to_tegra_mc(data);
+	const struct tegra_mc_client *client;
+	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);
+
+		client = &mc->soc->clients[idx];
+		ndata->node = node;
+
+		switch (client->swgroup) {
+		case TEGRA_SWGROUP_DC:
+		case TEGRA_SWGROUP_DCB:
+		case TEGRA_SWGROUP_PTC:
+		case TEGRA_SWGROUP_VI:
+			/* these clients are isochronous by default */
+			ndata->tag = TEGRA_MC_ICC_TAG_ISO;
+			break;
+
+		default:
+			ndata->tag = TEGRA_MC_ICC_TAG_DEFAULT;
+			break;
+		}
+
+		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 tegra124_mc_icc_ops = {
+	.xlate_extended = tegra124_mc_of_icc_xlate_extended,
+	.aggregate = tegra124_mc_icc_aggreate,
+	.set = tegra124_mc_icc_set,
+};
+
 #ifdef CONFIG_ARCH_TEGRA_124_SOC
 static const unsigned long tegra124_mc_emem_regs[] = {
 	MC_EMEM_ARB_CFG,
@@ -1061,6 +1139,7 @@ const struct tegra_mc_soc tegra124_mc_soc = {
 	.reset_ops = &tegra_mc_reset_ops_common,
 	.resets = tegra124_mc_resets,
 	.num_resets = ARRAY_SIZE(tegra124_mc_resets),
+	.icc_ops = &tegra124_mc_icc_ops,
 };
 #endif /* CONFIG_ARCH_TEGRA_124_SOC */
 
@@ -1091,5 +1170,6 @@ const struct tegra_mc_soc tegra132_mc_soc = {
 	.reset_ops = &tegra_mc_reset_ops_common,
 	.resets = tegra124_mc_resets,
 	.num_resets = ARRAY_SIZE(tegra124_mc_resets),
+	.icc_ops = &tegra124_mc_icc_ops,
 };
 #endif /* CONFIG_ARCH_TEGRA_132_SOC */
-- 
2.29.2

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