1 files changed, 470 insertions, 50 deletions

diff --git a/drivers/memory/tegra/tegra20-emc.c b/drivers/memory/tegra/tegra20-emc.c
index 027f46287dbf..686aaf477d8a 100644
--- a/drivers/memory/tegra/tegra20-emc.c
+++ b/drivers/memory/tegra/tegra20-emc.c
@@ -8,19 +8,27 @@
 #include <linux/clk.h>
 #include <linux/clk/tegra.h>
 #include <linux/debugfs.h>
+#include <linux/devfreq.h>
 #include <linux/err.h>
+#include <linux/interconnect-provider.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/iopoll.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/slab.h>
 #include <linux/sort.h>
 #include <linux/types.h>
 
+#include <soc/tegra/common.h>
 #include <soc/tegra/fuse.h>
 
+#include "mc.h"
+
 #define EMC_INTSTATUS				0x000
 #define EMC_INTMASK				0x004
 #define EMC_DBG					0x008
@@ -62,6 +70,11 @@
 #define EMC_ODT_READ				0x0b4
 #define EMC_FBIO_CFG5				0x104
 #define EMC_FBIO_CFG6				0x114
+#define EMC_STAT_CONTROL			0x160
+#define EMC_STAT_LLMC_CONTROL			0x178
+#define EMC_STAT_PWR_CLOCK_LIMIT		0x198
+#define EMC_STAT_PWR_CLOCKS			0x19c
+#define EMC_STAT_PWR_COUNT			0x1a0
 #define EMC_AUTO_CAL_INTERVAL			0x2a8
 #define EMC_CFG_2				0x2b8
 #define EMC_CFG_DIG_DLL				0x2bc
@@ -88,6 +101,12 @@
 #define EMC_DBG_READ_DQM_CTRL			BIT(9)
 #define EMC_DBG_CFG_PRIORITY			BIT(24)
 
+#define EMC_FBIO_CFG5_DRAM_WIDTH_X16		BIT(4)
+
+#define EMC_PWR_GATHER_CLEAR			(1 << 8)
+#define EMC_PWR_GATHER_DISABLE			(2 << 8)
+#define EMC_PWR_GATHER_ENABLE			(3 << 8)
+
 static const u16 emc_timing_registers[] = {
 	EMC_RC,
 	EMC_RFC,
@@ -142,11 +161,26 @@ struct emc_timing {
 	u32 data[ARRAY_SIZE(emc_timing_registers)];
 };
 
+enum emc_rate_request_type {
+	EMC_RATE_DEVFREQ,
+	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;
+	struct tegra_mc *mc;
+	struct icc_provider provider;
 	struct notifier_block clk_nb;
 	struct clk *clk;
 	void __iomem *regs;
+	unsigned int dram_bus_width;
 
 	struct emc_timing *timings;
 	unsigned int num_timings;
@@ -156,6 +190,17 @@ struct tegra_emc {
 		unsigned long min_rate;
 		unsigned long max_rate;
 	} debugfs;
+
+	/*
+	 * 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;
+
+	struct devfreq_simple_ondemand_data ondemand_data;
 };
 
 static irqreturn_t tegra_emc_isr(int irq, void *data)
@@ -383,6 +428,11 @@ tegra_emc_find_node_by_ram_code(struct device *dev)
 	u32 value, ram_code;
 	int err;
 
+	if (of_get_child_count(dev->of_node) == 0) {
+		dev_info(dev, "device-tree doesn't have memory timings\n");
+		return NULL;
+	}
+
 	if (!of_property_read_bool(dev->of_node, "nvidia,use-ram-code"))
 		return of_node_get(dev->of_node);
 
@@ -408,7 +458,7 @@ 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;
-	u32 emc_cfg, emc_dbg;
+	u32 emc_cfg, emc_dbg, emc_fbio;
 
 	emc_cfg = readl_relaxed(emc->regs + EMC_CFG_2);
 
@@ -439,6 +489,15 @@ static int emc_setup_hw(struct tegra_emc *emc)
 	emc_dbg &= ~EMC_DBG_FORCE_UPDATE;
 	writel_relaxed(emc_dbg, emc->regs + EMC_DBG);
 
+	emc_fbio = readl_relaxed(emc->regs + EMC_FBIO_CFG5);
+
+	if (emc_fbio & EMC_FBIO_CFG5_DRAM_WIDTH_X16)
+		emc->dram_bus_width = 16;
+	else
+		emc->dram_bus_width = 32;
+
+	dev_info(emc->dev, "%ubit DRAM bus\n", emc->dram_bus_width);
+
 	return 0;
 }
 
@@ -451,6 +510,9 @@ static long emc_round_rate(unsigned long rate,
 	struct tegra_emc *emc = arg;
 	unsigned int i;
 
+	if (!emc->num_timings)
+		return clk_get_rate(emc->clk);
+
 	min_rate = min(min_rate, emc->timings[emc->num_timings - 1].rate);
 
 	for (i = 0; i < emc->num_timings; i++) {
@@ -480,6 +542,83 @@ static long emc_round_rate(unsigned long rate,
 	return timing->rate;
 }
 
+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
  *
@@ -563,7 +702,7 @@ 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;
 
@@ -593,7 +732,7 @@ 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;
 
@@ -650,47 +789,330 @@ static void tegra_emc_debugfs_init(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;
+	int err;
+
+	/*
+	 * Tegra20 EMC runs on x2 clock rate of SDRAM bus because DDR data
+	 * is sampled on both clock edges.  This means that EMC clock rate
+	 * equals to the peak data-rate.
+	 */
+	dram_data_bus_width_bytes = emc->dram_bus_width / 8;
+	do_div(rate, 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;
+	struct icc_node *node;
+	int err;
+
+	emc->mc = devm_tegra_memory_controller_get(emc->dev);
+	if (IS_ERR(emc->mc))
+		return PTR_ERR(emc->mc);
+
+	soc = emc->mc->soc;
+
+	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_process_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)
+{
+	tegra20_clk_set_emc_round_callback(NULL, NULL);
+}
+
+static void devm_tegra_emc_unreg_clk_notifier(void *data)
+{
+	struct tegra_emc *emc = data;
+
+	clk_notifier_unregister(emc->clk, &emc->clk_nb);
+}
+
+static int tegra_emc_init_clk(struct tegra_emc *emc)
+{
+	int err;
+
+	tegra20_clk_set_emc_round_callback(emc_round_rate, emc);
+
+	err = devm_add_action_or_reset(emc->dev, devm_tegra_emc_unset_callback,
+				       NULL);
+	if (err)
+		return err;
+
+	emc->clk = devm_clk_get(emc->dev, NULL);
+	if (IS_ERR(emc->clk)) {
+		dev_err(emc->dev, "failed to get EMC clock: %pe\n", emc->clk);
+		return PTR_ERR(emc->clk);
+	}
+
+	err = clk_notifier_register(emc->clk, &emc->clk_nb);
+	if (err) {
+		dev_err(emc->dev, "failed to register clk notifier: %d\n", err);
+		return err;
+	}
+
+	err = devm_add_action_or_reset(emc->dev,
+				       devm_tegra_emc_unreg_clk_notifier, emc);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static int tegra_emc_devfreq_target(struct device *dev, unsigned long *freq,
+				    u32 flags)
+{
+	struct tegra_emc *emc = dev_get_drvdata(dev);
+	struct dev_pm_opp *opp;
+	unsigned long rate;
+
+	opp = devfreq_recommended_opp(dev, freq, flags);
+	if (IS_ERR(opp)) {
+		dev_err(dev, "failed to find opp for %lu Hz\n", *freq);
+		return PTR_ERR(opp);
+	}
+
+	rate = dev_pm_opp_get_freq(opp);
+	dev_pm_opp_put(opp);
+
+	return emc_set_min_rate(emc, rate, EMC_RATE_DEVFREQ);
+}
+
+static int tegra_emc_devfreq_get_dev_status(struct device *dev,
+					    struct devfreq_dev_status *stat)
+{
+	struct tegra_emc *emc = dev_get_drvdata(dev);
+
+	/* freeze counters */
+	writel_relaxed(EMC_PWR_GATHER_DISABLE, emc->regs + EMC_STAT_CONTROL);
+
+	/*
+	 *  busy_time: number of clocks EMC request was accepted
+	 * total_time: number of clocks PWR_GATHER control was set to ENABLE
+	 */
+	stat->busy_time = readl_relaxed(emc->regs + EMC_STAT_PWR_COUNT);
+	stat->total_time = readl_relaxed(emc->regs + EMC_STAT_PWR_CLOCKS);
+	stat->current_frequency = clk_get_rate(emc->clk);
+
+	/* clear counters and restart */
+	writel_relaxed(EMC_PWR_GATHER_CLEAR, emc->regs + EMC_STAT_CONTROL);
+	writel_relaxed(EMC_PWR_GATHER_ENABLE, emc->regs + EMC_STAT_CONTROL);
+
+	return 0;
+}
+
+static struct devfreq_dev_profile tegra_emc_devfreq_profile = {
+	.polling_ms = 30,
+	.target = tegra_emc_devfreq_target,
+	.get_dev_status = tegra_emc_devfreq_get_dev_status,
+};
+
+static int tegra_emc_devfreq_init(struct tegra_emc *emc)
+{
+	struct devfreq *devfreq;
+
+	/*
+	 * PWR_COUNT is 1/2 of PWR_CLOCKS at max, and thus, the up-threshold
+	 * should be less than 50.  Secondly, multiple active memory clients
+	 * may cause over 20% of lost clock cycles due to stalls caused by
+	 * competing memory accesses.  This means that threshold should be
+	 * set to a less than 30 in order to have a properly working governor.
+	 */
+	emc->ondemand_data.upthreshold = 20;
+
+	/*
+	 * Reset statistic gathers state, select global bandwidth for the
+	 * statistics collection mode and set clocks counter saturation
+	 * limit to maximum.
+	 */
+	writel_relaxed(0x00000000, emc->regs + EMC_STAT_CONTROL);
+	writel_relaxed(0x00000000, emc->regs + EMC_STAT_LLMC_CONTROL);
+	writel_relaxed(0xffffffff, emc->regs + EMC_STAT_PWR_CLOCK_LIMIT);
+
+	devfreq = devm_devfreq_add_device(emc->dev, &tegra_emc_devfreq_profile,
+					  DEVFREQ_GOV_SIMPLE_ONDEMAND,
+					  &emc->ondemand_data);
+	if (IS_ERR(devfreq)) {
+		dev_err(emc->dev, "failed to initialize devfreq: %pe", devfreq);
+		return PTR_ERR(devfreq);
+	}
+
+	return 0;
+}
+
 static int tegra_emc_probe(struct platform_device *pdev)
 {
 	struct device_node *np;
 	struct tegra_emc *emc;
-	struct resource *res;
 	int irq, err;
 
-	/* driver has nothing to do in a case of memory timing absence */
-	if (of_get_child_count(pdev->dev.of_node) == 0) {
-		dev_info(&pdev->dev,
-			 "EMC device tree node doesn't have memory timings\n");
-		return 0;
-	}
-
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0) {
-		dev_err(&pdev->dev, "interrupt not specified\n");
 		dev_err(&pdev->dev, "please update your device tree\n");
 		return irq;
 	}
 
-	np = tegra_emc_find_node_by_ram_code(&pdev->dev);
-	if (!np)
-		return -EINVAL;
-
 	emc = devm_kzalloc(&pdev->dev, sizeof(*emc), GFP_KERNEL);
-	if (!emc) {
-		of_node_put(np);
+	if (!emc)
 		return -ENOMEM;
-	}
 
+	mutex_init(&emc->rate_lock);
 	emc->clk_nb.notifier_call = tegra_emc_clk_change_notify;
 	emc->dev = &pdev->dev;
 
-	err = tegra_emc_load_timings_from_dt(emc, np);
-	of_node_put(np);
-	if (err)
-		return err;
+	np = tegra_emc_find_node_by_ram_code(&pdev->dev);
+	if (np) {
+		err = tegra_emc_load_timings_from_dt(emc, np);
+		of_node_put(np);
+		if (err)
+			return err;
+	}
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	emc->regs = devm_ioremap_resource(&pdev->dev, res);
+	emc->regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(emc->regs))
 		return PTR_ERR(emc->regs);
 
@@ -701,41 +1123,39 @@ static int tegra_emc_probe(struct platform_device *pdev)
 	err = devm_request_irq(&pdev->dev, irq, tegra_emc_isr, 0,
 			       dev_name(&pdev->dev), emc);
 	if (err) {
-		dev_err(&pdev->dev, "failed to request IRQ#%u: %d\n", irq, err);
+		dev_err(&pdev->dev, "failed to request IRQ: %d\n", err);
 		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);
-		goto unset_cb;
-	}
+	err = tegra_emc_init_clk(emc);
+	if (err)
+		return err;
 
-	err = clk_notifier_register(emc->clk, &emc->clk_nb);
-	if (err) {
-		dev_err(&pdev->dev, "failed to register clk notifier: %d\n",
-			err);
-		goto unset_cb;
-	}
+	err = tegra_emc_opp_table_init(emc);
+	if (err)
+		return err;
 
 	platform_set_drvdata(pdev, emc);
+	tegra_emc_rate_requests_init(emc);
 	tegra_emc_debugfs_init(emc);
+	tegra_emc_interconnect_init(emc);
+	tegra_emc_devfreq_init(emc);
 
-	return 0;
-
-unset_cb:
-	tegra20_clk_set_emc_round_callback(NULL, NULL);
+	/*
+	 * 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
+	 * this driver.
+	 */
+	try_module_get(THIS_MODULE);
 
-	return err;
+	return 0;
 }
 
 static const struct of_device_id tegra_emc_of_match[] = {
 	{ .compatible = "nvidia,tegra20-emc", },
 	{},
 };
+MODULE_DEVICE_TABLE(of, tegra_emc_of_match);
 
 static struct platform_driver tegra_emc_driver = {
 	.probe = tegra_emc_probe,
@@ -743,11 +1163,11 @@ static struct platform_driver tegra_emc_driver = {
 		.name = "tegra20-emc",
 		.of_match_table = tegra_emc_of_match,
 		.suppress_bind_attrs = true,
+		.sync_state = icc_sync_state,
 	},
 };
+module_platform_driver(tegra_emc_driver);
 
-static int __init tegra_emc_init(void)
-{
-	return platform_driver_register(&tegra_emc_driver);
-}
-subsys_initcall(tegra_emc_init);
+MODULE_AUTHOR("Dmitry Osipenko <digetx@gmail.com>");
+MODULE_DESCRIPTION("NVIDIA Tegra20 EMC driver");
+MODULE_LICENSE("GPL v2");