memory: tegra124: 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.

Tested-by: Nicolas Chauvet <kwizart@gmail.com>
Acked-by: Georgi Djakov <georgi.djakov@linaro.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20201228154920.18846-4-digetx@gmail.com
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

1 files changed, 309 insertions, 11 deletions

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);