memory: emif: add device tree support to emif driver

Device tree support for the EMIF driver. LPDDR2 generic timings
extraction from device is managed using couple of helper
functions which can be used by other memory controller
drivers.

Reviewed-by: Benoit Cousson <b-cousson@ti.com>
Reviewed-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Aneesh V <aneesh@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/memory/Makefile

@@ -2,6 +2,7 @@
 # Makefile for memory devices
 #
 
+obj-$(CONFIG_OF)		+= of_memory.o
 obj-$(CONFIG_TI_EMIF)		+= emif.o
 obj-$(CONFIG_TEGRA20_MC)	+= tegra20-mc.o
 obj-$(CONFIG_TEGRA30_MC)	+= tegra30-mc.o

drivers/memory/emif.c

@@ -18,6 +18,7 @@
 #include <linux/platform_device.h>
 #include <linux/interrupt.h>
 #include <linux/slab.h>
+#include <linux/of.h>
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
 #include <linux/module.h>
@@ -25,6 +26,7 @@
 #include <linux/spinlock.h>
 #include <memory/jedec_ddr.h>
 #include "emif.h"
+#include "of_memory.h"
 
 /**
  * struct emif_data - Per device static data for driver's use
@@ -49,6 +51,7 @@
  *				frequency in effect at the moment)
  * @plat_data:			Pointer to saved platform data.
  * @debugfs_root:		dentry to the root folder for EMIF in debugfs
+ * @np_ddr:			Pointer to ddr device tree node
  */
 struct emif_data {
 	u8				duplicate;
@@ -63,6 +66,7 @@ struct emif_data {
 	struct emif_regs		*curr_regs;
 	struct emif_platform_data	*plat_data;
 	struct dentry			*debugfs_root;
+	struct device_node		*np_ddr;
 };
 
 static struct emif_data *emif1;
@@ -1148,6 +1152,168 @@ static int is_custom_config_valid(struct emif_custom_configs *cust_cfgs,
 	return valid;
 }
 
+#if defined(CONFIG_OF)
+static void __init_or_module of_get_custom_configs(struct device_node *np_emif,
+		struct emif_data *emif)
+{
+	struct emif_custom_configs	*cust_cfgs = NULL;
+	int				len;
+	const int			*lpmode, *poll_intvl;
+
+	lpmode = of_get_property(np_emif, "low-power-mode", &len);
+	poll_intvl = of_get_property(np_emif, "temp-alert-poll-interval", &len);
+
+	if (lpmode || poll_intvl)
+		cust_cfgs = devm_kzalloc(emif->dev, sizeof(*cust_cfgs),
+			GFP_KERNEL);
+
+	if (!cust_cfgs)
+		return;
+
+	if (lpmode) {
+		cust_cfgs->mask |= EMIF_CUSTOM_CONFIG_LPMODE;
+		cust_cfgs->lpmode = *lpmode;
+		of_property_read_u32(np_emif,
+				"low-power-mode-timeout-performance",
+				&cust_cfgs->lpmode_timeout_performance);
+		of_property_read_u32(np_emif,
+				"low-power-mode-timeout-power",
+				&cust_cfgs->lpmode_timeout_power);
+		of_property_read_u32(np_emif,
+				"low-power-mode-freq-threshold",
+				&cust_cfgs->lpmode_freq_threshold);
+	}
+
+	if (poll_intvl) {
+		cust_cfgs->mask |=
+				EMIF_CUSTOM_CONFIG_TEMP_ALERT_POLL_INTERVAL;
+		cust_cfgs->temp_alert_poll_interval_ms = *poll_intvl;
+	}
+
+	if (!is_custom_config_valid(cust_cfgs, emif->dev)) {
+		devm_kfree(emif->dev, cust_cfgs);
+		return;
+	}
+
+	emif->plat_data->custom_configs = cust_cfgs;
+}
+
+static void __init_or_module of_get_ddr_info(struct device_node *np_emif,
+		struct device_node *np_ddr,
+		struct ddr_device_info *dev_info)
+{
+	u32 density = 0, io_width = 0;
+	int len;
+
+	if (of_find_property(np_emif, "cs1-used", &len))
+		dev_info->cs1_used = true;
+
+	if (of_find_property(np_emif, "cal-resistor-per-cs", &len))
+		dev_info->cal_resistors_per_cs = true;
+
+	if (of_device_is_compatible(np_ddr , "jedec,lpddr2-s4"))
+		dev_info->type = DDR_TYPE_LPDDR2_S4;
+	else if (of_device_is_compatible(np_ddr , "jedec,lpddr2-s2"))
+		dev_info->type = DDR_TYPE_LPDDR2_S2;
+
+	of_property_read_u32(np_ddr, "density", &density);
+	of_property_read_u32(np_ddr, "io-width", &io_width);
+
+	/* Convert from density in Mb to the density encoding in jedc_ddr.h */
+	if (density & (density - 1))
+		dev_info->density = 0;
+	else
+		dev_info->density = __fls(density) - 5;
+
+	/* Convert from io_width in bits to io_width encoding in jedc_ddr.h */
+	if (io_width & (io_width - 1))
+		dev_info->io_width = 0;
+	else
+		dev_info->io_width = __fls(io_width) - 1;
+}
+
+static struct emif_data * __init_or_module of_get_memory_device_details(
+		struct device_node *np_emif, struct device *dev)
+{
+	struct emif_data		*emif = NULL;
+	struct ddr_device_info		*dev_info = NULL;
+	struct emif_platform_data	*pd = NULL;
+	struct device_node		*np_ddr;
+	int				len;
+
+	np_ddr = of_parse_phandle(np_emif, "device-handle", 0);
+	if (!np_ddr)
+		goto error;
+	emif	= devm_kzalloc(dev, sizeof(struct emif_data), GFP_KERNEL);
+	pd	= devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
+	dev_info = devm_kzalloc(dev, sizeof(*dev_info), GFP_KERNEL);
+
+	if (!emif || !pd || !dev_info) {
+		dev_err(dev, "%s: Out of memory!!\n",
+			__func__);
+		goto error;
+	}
+
+	emif->plat_data		= pd;
+	pd->device_info		= dev_info;
+	emif->dev		= dev;
+	emif->np_ddr		= np_ddr;
+	emif->temperature_level	= SDRAM_TEMP_NOMINAL;
+
+	if (of_device_is_compatible(np_emif, "ti,emif-4d"))
+		emif->plat_data->ip_rev = EMIF_4D;
+	else if (of_device_is_compatible(np_emif, "ti,emif-4d5"))
+		emif->plat_data->ip_rev = EMIF_4D5;
+
+	of_property_read_u32(np_emif, "phy-type", &pd->phy_type);
+
+	if (of_find_property(np_emif, "hw-caps-ll-interface", &len))
+		pd->hw_caps |= EMIF_HW_CAPS_LL_INTERFACE;
+
+	of_get_ddr_info(np_emif, np_ddr, dev_info);
+	if (!is_dev_data_valid(pd->device_info->type, pd->device_info->density,
+			pd->device_info->io_width, pd->phy_type, pd->ip_rev,
+			emif->dev)) {
+		dev_err(dev, "%s: invalid device data!!\n", __func__);
+		goto error;
+	}
+	/*
+	 * For EMIF instances other than EMIF1 see if the devices connected
+	 * are exactly same as on EMIF1(which is typically the case). If so,
+	 * mark it as a duplicate of EMIF1. This will save some memory and
+	 * computation.
+	 */
+	if (emif1 && emif1->np_ddr == np_ddr) {
+		emif->duplicate = true;
+		goto out;
+	} else if (emif1) {
+		dev_warn(emif->dev, "%s: Non-symmetric DDR geometry\n",
+			__func__);
+	}
+
+	of_get_custom_configs(np_emif, emif);
+	emif->plat_data->timings = of_get_ddr_timings(np_ddr, emif->dev,
+					emif->plat_data->device_info->type,
+					&emif->plat_data->timings_arr_size);
+
+	emif->plat_data->min_tck = of_get_min_tck(np_ddr, emif->dev);
+	goto out;
+
+error:
+	return NULL;
+out:
+	return emif;
+}
+
+#else
+
+static struct emif_data * __init_or_module of_get_memory_device_details(
+		struct device_node *np_emif, struct device *dev)
+{
+	return NULL;
+}
+#endif
+
 static struct emif_data *__init_or_module get_device_details(
 		struct platform_device *pdev)
 {
@@ -1267,7 +1433,11 @@ static int __init_or_module emif_probe(struct platform_device *pdev)
 	struct resource		*res;
 	int			irq;
 
-	emif = get_device_details(pdev);
+	if (pdev->dev.of_node)
+		emif = of_get_memory_device_details(pdev->dev.of_node, &pdev->dev);
+	else
+		emif = get_device_details(pdev);
+
 	if (!emif) {
 		pr_err("%s: error getting device data\n", __func__);
 		goto error;
@@ -1644,11 +1814,21 @@ static void __attribute__((unused)) freq_post_notify_handling(void)
 	spin_unlock_irqrestore(&emif_lock, irq_state);
 }
 
+#if defined(CONFIG_OF)
+static const struct of_device_id emif_of_match[] = {
+		{ .compatible = "ti,emif-4d" },
+		{ .compatible = "ti,emif-4d5" },
+		{},
+};
+MODULE_DEVICE_TABLE(of, emif_of_match);
+#endif
+
 static struct platform_driver emif_driver = {
 	.remove		= __exit_p(emif_remove),
 	.shutdown	= emif_shutdown,
 	.driver = {
 		.name = "emif",
+		.of_match_table = of_match_ptr(emif_of_match),
 	},
 };
 

drivers/memory/of_memory.c

@@ -0,0 +1,153 @@
+/*
+ * OpenFirmware helpers for memory drivers
+ *
+ * Copyright (C) 2012 Texas Instruments, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/list.h>
+#include <linux/of.h>
+#include <linux/gfp.h>
+#include <memory/jedec_ddr.h>
+#include <linux/export.h>
+
+/**
+ * of_get_min_tck() - extract min timing values for ddr
+ * @np: pointer to ddr device tree node
+ * @device: device requesting for min timing values
+ *
+ * Populates the lpddr2_min_tck structure by extracting data
+ * from device tree node. Returns a pointer to the populated
+ * structure. If any error in populating the structure, returns
+ * default min timings provided by JEDEC.
+ */
+const struct lpddr2_min_tck *of_get_min_tck(struct device_node *np,
+		struct device *dev)
+{
+	int			ret = 0;
+	struct lpddr2_min_tck	*min;
+
+	min = devm_kzalloc(dev, sizeof(*min), GFP_KERNEL);
+	if (!min)
+		goto default_min_tck;
+
+	ret |= of_property_read_u32(np, "tRPab-min-tck", &min->tRPab);
+	ret |= of_property_read_u32(np, "tRCD-min-tck", &min->tRCD);
+	ret |= of_property_read_u32(np, "tWR-min-tck", &min->tWR);
+	ret |= of_property_read_u32(np, "tRASmin-min-tck", &min->tRASmin);
+	ret |= of_property_read_u32(np, "tRRD-min-tck", &min->tRRD);
+	ret |= of_property_read_u32(np, "tWTR-min-tck", &min->tWTR);
+	ret |= of_property_read_u32(np, "tXP-min-tck", &min->tXP);
+	ret |= of_property_read_u32(np, "tRTP-min-tck", &min->tRTP);
+	ret |= of_property_read_u32(np, "tCKE-min-tck", &min->tCKE);
+	ret |= of_property_read_u32(np, "tCKESR-min-tck", &min->tCKESR);
+	ret |= of_property_read_u32(np, "tFAW-min-tck", &min->tFAW);
+
+	if (ret) {
+		devm_kfree(dev, min);
+		goto default_min_tck;
+	}
+
+	return min;
+
+default_min_tck:
+	dev_warn(dev, "%s: using default min-tck values\n", __func__);
+	return &lpddr2_jedec_min_tck;
+}
+EXPORT_SYMBOL(of_get_min_tck);
+
+static int of_do_get_timings(struct device_node *np,
+		struct lpddr2_timings *tim)
+{
+	int ret;
+
+	ret = of_property_read_u32(np, "max-freq", &tim->max_freq);
+	ret |= of_property_read_u32(np, "min-freq", &tim->min_freq);
+	ret |= of_property_read_u32(np, "tRPab", &tim->tRPab);
+	ret |= of_property_read_u32(np, "tRCD", &tim->tRCD);
+	ret |= of_property_read_u32(np, "tWR", &tim->tWR);
+	ret |= of_property_read_u32(np, "tRAS-min", &tim->tRAS_min);
+	ret |= of_property_read_u32(np, "tRRD", &tim->tRRD);
+	ret |= of_property_read_u32(np, "tWTR", &tim->tWTR);
+	ret |= of_property_read_u32(np, "tXP", &tim->tXP);
+	ret |= of_property_read_u32(np, "tRTP", &tim->tRTP);
+	ret |= of_property_read_u32(np, "tCKESR", &tim->tCKESR);
+	ret |= of_property_read_u32(np, "tDQSCK-max", &tim->tDQSCK_max);
+	ret |= of_property_read_u32(np, "tFAW", &tim->tFAW);
+	ret |= of_property_read_u32(np, "tZQCS", &tim->tZQCS);
+	ret |= of_property_read_u32(np, "tZQCL", &tim->tZQCL);
+	ret |= of_property_read_u32(np, "tZQinit", &tim->tZQinit);
+	ret |= of_property_read_u32(np, "tRAS-max-ns", &tim->tRAS_max_ns);
+	ret |= of_property_read_u32(np, "tDQSCK-max-derated",
+		&tim->tDQSCK_max_derated);
+
+	return ret;
+}
+
+/**
+ * of_get_ddr_timings() - extracts the ddr timings and updates no of
+ * frequencies available.
+ * @np_ddr: Pointer to ddr device tree node
+ * @dev: Device requesting for ddr timings
+ * @device_type: Type of ddr(LPDDR2 S2/S4)
+ * @nr_frequencies: No of frequencies available for ddr
+ * (updated by this function)
+ *
+ * Populates lpddr2_timings structure by extracting data from device
+ * tree node. Returns pointer to populated structure. If any error
+ * while populating, returns default timings provided by JEDEC.
+ */
+const struct lpddr2_timings *of_get_ddr_timings(struct device_node *np_ddr,
+		struct device *dev, u32 device_type, u32 *nr_frequencies)
+{
+	struct lpddr2_timings	*timings = NULL;
+	u32			arr_sz = 0, i = 0;
+	struct device_node	*np_tim;
+	char			*tim_compat;
+
+	switch (device_type) {
+	case DDR_TYPE_LPDDR2_S2:
+	case DDR_TYPE_LPDDR2_S4:
+		tim_compat = "jedec,lpddr2-timings";
+		break;
+	default:
+		dev_warn(dev, "%s: un-supported memory type\n", __func__);
+	}
+
+	for_each_child_of_node(np_ddr, np_tim)
+		if (of_device_is_compatible(np_tim, tim_compat))
+			arr_sz++;
+
+	if (arr_sz)
+		timings = devm_kzalloc(dev, sizeof(*timings) * arr_sz,
+			GFP_KERNEL);
+
+	if (!timings)
+		goto default_timings;
+
+	for_each_child_of_node(np_ddr, np_tim) {
+		if (of_device_is_compatible(np_tim, tim_compat)) {
+			if (of_do_get_timings(np_tim, &timings[i])) {
+				devm_kfree(dev, timings);
+				goto default_timings;
+			}
+			i++;
+		}
+	}
+
+	*nr_frequencies = arr_sz;
+
+	return timings;
+
+default_timings:
+	dev_warn(dev, "%s: using default timings\n", __func__);
+	*nr_frequencies = ARRAY_SIZE(lpddr2_jedec_timings);
+	return lpddr2_jedec_timings;
+}
+EXPORT_SYMBOL(of_get_ddr_timings);

drivers/memory/of_memory.h

@@ -0,0 +1,36 @@
+/*
+ * OpenFirmware helpers for memory drivers
+ *
+ * Copyright (C) 2012 Texas Instruments, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef __LINUX_MEMORY_OF_REG_H
+#define __LINUX_MEMORY_OF_REG_H
+
+#ifdef CONFIG_OF
+extern const struct lpddr2_min_tck *of_get_min_tck(struct device_node *np,
+		struct device *dev);
+extern const struct lpddr2_timings
+	*of_get_ddr_timings(struct device_node *np_ddr, struct device *dev,
+	u32 device_type, u32 *nr_frequencies);
+#else
+static inline const struct lpddr2_min_tck
+	*of_get_min_tck(struct device_node *np, struct device *dev)
+{
+	return NULL;
+}
+
+static inline const struct lpddr2_timings
+	*of_get_ddr_timings(struct device_node *np_ddr, struct device *dev,
+	u32 device_type, u32 *nr_frequencies)
+{
+	return NULL;
+}
+#endif /* CONFIG_OF */
+
+#endif /* __LINUX_MEMORY_OF_REG_ */