1 files changed, 231 insertions, 68 deletions

diff --git a/drivers/memory/tegra/tegra20-emc.c b/drivers/memory/tegra/tegra20-emc.c
index 9ee5bef49e47..8ae474d9bfb9 100644
--- a/drivers/memory/tegra/tegra20-emc.c
+++ b/drivers/memory/tegra/tegra20-emc.c
@@ -6,10 +6,12 @@
  */
 
 #include <linux/clk.h>
+#include <linux/clk/tegra.h>
 #include <linux/completion.h>
+#include <linux/debugfs.h>
 #include <linux/err.h>
 #include <linux/interrupt.h>
-#include <linux/iopoll.h>
+#include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
@@ -21,6 +23,7 @@
 
 #define EMC_INTSTATUS				0x000
 #define EMC_INTMASK				0x004
+#define EMC_DBG					0x008
 #define EMC_TIMING_CONTROL			0x028
 #define EMC_RC					0x02c
 #define EMC_RFC					0x030
@@ -79,6 +82,12 @@
 #define EMC_REFRESH_OVERFLOW_INT		BIT(3)
 #define EMC_CLKCHANGE_COMPLETE_INT		BIT(4)
 
+#define EMC_DBG_READ_MUX_ASSEMBLY		BIT(0)
+#define EMC_DBG_WRITE_MUX_ACTIVE		BIT(1)
+#define EMC_DBG_FORCE_UPDATE			BIT(2)
+#define EMC_DBG_READ_DQM_CTRL			BIT(9)
+#define EMC_DBG_CFG_PRIORITY			BIT(24)
+
 static const u16 emc_timing_registers[] = {
 	EMC_RC,
 	EMC_RFC,
@@ -137,14 +146,17 @@ struct tegra_emc {
 	struct device *dev;
 	struct completion clk_handshake_complete;
 	struct notifier_block clk_nb;
-	struct clk *backup_clk;
-	struct clk *emc_mux;
-	struct clk *pll_m;
 	struct clk *clk;
 	void __iomem *regs;
 
 	struct emc_timing *timings;
 	unsigned int num_timings;
+
+	struct {
+		struct dentry *root;
+		unsigned long min_rate;
+		unsigned long max_rate;
+	} debugfs;
 };
 
 static irqreturn_t tegra_emc_isr(int irq, void *data)
@@ -219,7 +231,7 @@ static int emc_prepare_timing_change(struct tegra_emc *emc, unsigned long rate)
 
 static int emc_complete_timing_change(struct tegra_emc *emc, bool flush)
 {
-	long timeout;
+	unsigned long timeout;
 
 	dev_dbg(emc->dev, "%s: flush %d\n", __func__, flush);
 
@@ -231,14 +243,10 @@ static int emc_complete_timing_change(struct tegra_emc *emc, bool flush)
 	}
 
 	timeout = wait_for_completion_timeout(&emc->clk_handshake_complete,
-					      usecs_to_jiffies(100));
+					      msecs_to_jiffies(100));
 	if (timeout == 0) {
 		dev_err(emc->dev, "EMC-CAR handshake failed\n");
 		return -EIO;
-	} else if (timeout < 0) {
-		dev_err(emc->dev, "failed to wait for EMC-CAR handshake: %ld\n",
-			timeout);
-		return timeout;
 	}
 
 	return 0;
@@ -363,6 +371,13 @@ static int tegra_emc_load_timings_from_dt(struct tegra_emc *emc,
 	sort(emc->timings, emc->num_timings, sizeof(*timing), cmp_timings,
 	     NULL);
 
+	dev_info(emc->dev,
+		 "got %u timings for RAM code %u (min %luMHz max %luMHz)\n",
+		 emc->num_timings,
+		 tegra_read_ram_code(),
+		 emc->timings[0].rate / 1000000,
+		 emc->timings[emc->num_timings - 1].rate / 1000000);
+
 	return 0;
 }
 
@@ -398,7 +413,7 @@ tegra_emc_find_node_by_ram_code(struct device *dev)
 static int emc_setup_hw(struct tegra_emc *emc)
 {
 	u32 intmask = EMC_REFRESH_OVERFLOW_INT | EMC_CLKCHANGE_COMPLETE_INT;
-	u32 emc_cfg;
+	u32 emc_cfg, emc_dbg;
 
 	emc_cfg = readl_relaxed(emc->regs + EMC_CFG_2);
 
@@ -421,42 +436,218 @@ static int emc_setup_hw(struct tegra_emc *emc)
 	writel_relaxed(intmask, emc->regs + EMC_INTMASK);
 	writel_relaxed(intmask, emc->regs + EMC_INTSTATUS);
 
+	/* ensure that unwanted debug features are disabled */
+	emc_dbg = readl_relaxed(emc->regs + EMC_DBG);
+	emc_dbg |= EMC_DBG_CFG_PRIORITY;
+	emc_dbg &= ~EMC_DBG_READ_MUX_ASSEMBLY;
+	emc_dbg &= ~EMC_DBG_WRITE_MUX_ACTIVE;
+	emc_dbg &= ~EMC_DBG_FORCE_UPDATE;
+	writel_relaxed(emc_dbg, emc->regs + EMC_DBG);
+
 	return 0;
 }
 
-static int emc_init(struct tegra_emc *emc, unsigned long rate)
+static long emc_round_rate(unsigned long rate,
+			   unsigned long min_rate,
+			   unsigned long max_rate,
+			   void *arg)
 {
+	struct emc_timing *timing = NULL;
+	struct tegra_emc *emc = arg;
+	unsigned int i;
+
+	min_rate = min(min_rate, emc->timings[emc->num_timings - 1].rate);
+
+	for (i = 0; i < emc->num_timings; i++) {
+		if (emc->timings[i].rate < rate && i != emc->num_timings - 1)
+			continue;
+
+		if (emc->timings[i].rate > max_rate) {
+			i = max(i, 1u) - 1;
+
+			if (emc->timings[i].rate < min_rate)
+				break;
+		}
+
+		if (emc->timings[i].rate < min_rate)
+			continue;
+
+		timing = &emc->timings[i];
+		break;
+	}
+
+	if (!timing) {
+		dev_err(emc->dev, "no timing for rate %lu min %lu max %lu\n",
+			rate, min_rate, max_rate);
+		return -EINVAL;
+	}
+
+	return timing->rate;
+}
+
+/*
+ * debugfs interface
+ *
+ * The memory controller driver exposes some files in debugfs that can be used
+ * to control the EMC frequency. The top-level directory can be found here:
+ *
+ *   /sys/kernel/debug/emc
+ *
+ * It contains the following files:
+ *
+ *   - available_rates: This file contains a list of valid, space-separated
+ *     EMC frequencies.
+ *
+ *   - min_rate: Writing a value to this file sets the given frequency as the
+ *       floor of the permitted range. If this is higher than the currently
+ *       configured EMC frequency, this will cause the frequency to be
+ *       increased so that it stays within the valid range.
+ *
+ *   - max_rate: Similarily to the min_rate file, writing a value to this file
+ *       sets the given frequency as the ceiling of the permitted range. If
+ *       the value is lower than the currently configured EMC frequency, this
+ *       will cause the frequency to be decreased so that it stays within the
+ *       valid range.
+ */
+
+static bool tegra_emc_validate_rate(struct tegra_emc *emc, unsigned long rate)
+{
+	unsigned int i;
+
+	for (i = 0; i < emc->num_timings; i++)
+		if (rate == emc->timings[i].rate)
+			return true;
+
+	return false;
+}
+
+static int tegra_emc_debug_available_rates_show(struct seq_file *s, void *data)
+{
+	struct tegra_emc *emc = s->private;
+	const char *prefix = "";
+	unsigned int i;
+
+	for (i = 0; i < emc->num_timings; i++) {
+		seq_printf(s, "%s%lu", prefix, emc->timings[i].rate);
+		prefix = " ";
+	}
+
+	seq_puts(s, "\n");
+
+	return 0;
+}
+
+static int tegra_emc_debug_available_rates_open(struct inode *inode,
+						struct file *file)
+{
+	return single_open(file, tegra_emc_debug_available_rates_show,
+			   inode->i_private);
+}
+
+static const struct file_operations tegra_emc_debug_available_rates_fops = {
+	.open = tegra_emc_debug_available_rates_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
+static int tegra_emc_debug_min_rate_get(void *data, u64 *rate)
+{
+	struct tegra_emc *emc = data;
+
+	*rate = emc->debugfs.min_rate;
+
+	return 0;
+}
+
+static int tegra_emc_debug_min_rate_set(void *data, u64 rate)
+{
+	struct tegra_emc *emc = data;
 	int err;
 
-	err = clk_set_parent(emc->emc_mux, emc->backup_clk);
-	if (err) {
-		dev_err(emc->dev,
-			"failed to reparent to backup source: %d\n", err);
+	if (!tegra_emc_validate_rate(emc, rate))
+		return -EINVAL;
+
+	err = clk_set_min_rate(emc->clk, rate);
+	if (err < 0)
 		return err;
-	}
 
-	err = clk_set_rate(emc->pll_m, rate);
-	if (err) {
-		dev_err(emc->dev,
-			"failed to change pll_m rate: %d\n", err);
+	emc->debugfs.min_rate = rate;
+
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(tegra_emc_debug_min_rate_fops,
+			tegra_emc_debug_min_rate_get,
+			tegra_emc_debug_min_rate_set, "%llu\n");
+
+static int tegra_emc_debug_max_rate_get(void *data, u64 *rate)
+{
+	struct tegra_emc *emc = data;
+
+	*rate = emc->debugfs.max_rate;
+
+	return 0;
+}
+
+static int tegra_emc_debug_max_rate_set(void *data, u64 rate)
+{
+	struct tegra_emc *emc = data;
+	int err;
+
+	if (!tegra_emc_validate_rate(emc, rate))
+		return -EINVAL;
+
+	err = clk_set_max_rate(emc->clk, rate);
+	if (err < 0)
 		return err;
+
+	emc->debugfs.max_rate = rate;
+
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(tegra_emc_debug_max_rate_fops,
+			tegra_emc_debug_max_rate_get,
+			tegra_emc_debug_max_rate_set, "%llu\n");
+
+static void tegra_emc_debugfs_init(struct tegra_emc *emc)
+{
+	struct device *dev = emc->dev;
+	unsigned int i;
+	int err;
+
+	emc->debugfs.min_rate = ULONG_MAX;
+	emc->debugfs.max_rate = 0;
+
+	for (i = 0; i < emc->num_timings; i++) {
+		if (emc->timings[i].rate < emc->debugfs.min_rate)
+			emc->debugfs.min_rate = emc->timings[i].rate;
+
+		if (emc->timings[i].rate > emc->debugfs.max_rate)
+			emc->debugfs.max_rate = emc->timings[i].rate;
 	}
 
-	err = clk_set_parent(emc->emc_mux, emc->pll_m);
-	if (err) {
-		dev_err(emc->dev,
-			"failed to reparent to pll_m: %d\n", err);
-		return err;
+	err = clk_set_rate_range(emc->clk, emc->debugfs.min_rate,
+				 emc->debugfs.max_rate);
+	if (err < 0) {
+		dev_err(dev, "failed to set rate range [%lu-%lu] for %pC\n",
+			emc->debugfs.min_rate, emc->debugfs.max_rate,
+			emc->clk);
 	}
 
-	err = clk_set_rate(emc->clk, rate);
-	if (err) {
-		dev_err(emc->dev,
-			"failed to change emc rate: %d\n", err);
-		return err;
+	emc->debugfs.root = debugfs_create_dir("emc", NULL);
+	if (!emc->debugfs.root) {
+		dev_err(emc->dev, "failed to create debugfs directory\n");
+		return;
 	}
 
-	return 0;
+	debugfs_create_file("available_rates", S_IRUGO, emc->debugfs.root,
+			    emc, &tegra_emc_debug_available_rates_fops);
+	debugfs_create_file("min_rate", S_IRUGO | S_IWUSR, emc->debugfs.root,
+			    emc, &tegra_emc_debug_min_rate_fops);
+	debugfs_create_file("max_rate", S_IRUGO | S_IWUSR, emc->debugfs.root,
+			    emc, &tegra_emc_debug_max_rate_fops);
 }
 
 static int tegra_emc_probe(struct platform_device *pdev)
@@ -515,57 +706,29 @@ static int tegra_emc_probe(struct platform_device *pdev)
 		return err;
 	}
 
+	tegra20_clk_set_emc_round_callback(emc_round_rate, emc);
+
 	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;
-	}
-
-	emc->pll_m = clk_get_sys(NULL, "pll_m");
-	if (IS_ERR(emc->pll_m)) {
-		err = PTR_ERR(emc->pll_m);
-		dev_err(&pdev->dev, "failed to get pll_m clock: %d\n", err);
-		return err;
-	}
-
-	emc->backup_clk = clk_get_sys(NULL, "pll_p");
-	if (IS_ERR(emc->backup_clk)) {
-		err = PTR_ERR(emc->backup_clk);
-		dev_err(&pdev->dev, "failed to get pll_p clock: %d\n", err);
-		goto put_pll_m;
-	}
-
-	emc->emc_mux = clk_get_parent(emc->clk);
-	if (IS_ERR(emc->emc_mux)) {
-		err = PTR_ERR(emc->emc_mux);
-		dev_err(&pdev->dev, "failed to get emc_mux clock: %d\n", err);
-		goto put_backup;
+		goto unset_cb;
 	}
 
 	err = clk_notifier_register(emc->clk, &emc->clk_nb);
 	if (err) {
 		dev_err(&pdev->dev, "failed to register clk notifier: %d\n",
 			err);
-		goto put_backup;
+		goto unset_cb;
 	}
 
-	/* set DRAM clock rate to maximum */
-	err = emc_init(emc, emc->timings[emc->num_timings - 1].rate);
-	if (err) {
-		dev_err(&pdev->dev, "failed to initialize EMC clock rate: %d\n",
-			err);
-		goto unreg_notifier;
-	}
+	platform_set_drvdata(pdev, emc);
+	tegra_emc_debugfs_init(emc);
 
 	return 0;
 
-unreg_notifier:
-	clk_notifier_unregister(emc->clk, &emc->clk_nb);
-put_backup:
-	clk_put(emc->backup_clk);
-put_pll_m:
-	clk_put(emc->pll_m);
+unset_cb:
+	tegra20_clk_set_emc_round_callback(NULL, NULL);
 
 	return err;
 }