[PATCH v12 3/9] drivers: memory: extend of_memory by LPDDR3 support

[Lukasz Luba]

The patch adds AC timings information needed to support LPDDR3 and memory
controllers. The structure is used in of_memory and currently in Exynos
5422 DMC. Add parsing data needed for LPDDR3 support.
It is currently used in Exynos5422 Dynamic Memory Controller.

Acked-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
Signed-off-by: Lukasz Luba <l.luba@xxxxxxxxxxxxxxxxxxx>
---
 drivers/memory/jedec_ddr.h |  61 +++++++++++++++
 drivers/memory/of_memory.c | 154 +++++++++++++++++++++++++++++++++++++
 drivers/memory/of_memory.h |  18 +++++
 3 files changed, 233 insertions(+)

diff --git a/drivers/memory/jedec_ddr.h b/drivers/memory/jedec_ddr.h
index 4a21b5044ff8..38e26d461bdb 100644
--- a/drivers/memory/jedec_ddr.h
+++ b/drivers/memory/jedec_ddr.h
@@ -29,6 +29,7 @@
 #define DDR_TYPE_LPDDR2_S4	3
 #define DDR_TYPE_LPDDR2_S2	4
 #define DDR_TYPE_LPDDR2_NVM	5
+#define DDR_TYPE_LPDDR3		6
 
 /* DDR IO width */
 #define DDR_IO_WIDTH_4		1
@@ -169,4 +170,64 @@ extern const struct lpddr2_timings
 	lpddr2_jedec_timings[NUM_DDR_TIMING_TABLE_ENTRIES];
 extern const struct lpddr2_min_tck lpddr2_jedec_min_tck;
 
+/*
+ * Structure for timings for LPDDR3 based on LPDDR2 plus additional fields.
+ * All parameters are in pico seconds(ps) unless explicitly indicated
+ * with a suffix like tRAS_max_ns below
+ */
+struct lpddr3_timings {
+	u32 max_freq;
+	u32 min_freq;
+	u32 tRFC;
+	u32 tRRD;
+	u32 tRPab;
+	u32 tRPpb;
+	u32 tRCD;
+	u32 tRC;
+	u32 tRAS;
+	u32 tWTR;
+	u32 tWR;
+	u32 tRTP;
+	u32 tW2W_C2C;
+	u32 tR2R_C2C;
+	u32 tWL;
+	u32 tDQSCK;
+	u32 tRL;
+	u32 tFAW;
+	u32 tXSR;
+	u32 tXP;
+	u32 tCKE;
+	u32 tCKESR;
+	u32 tMRD;
+};
+
+/*
+ * Min value for some parameters in terms of number of tCK cycles(nCK)
+ * Please set to zero parameters that are not valid for a given memory
+ * type
+ */
+struct lpddr3_min_tck {
+	u32 tRFC;
+	u32 tRRD;
+	u32 tRPab;
+	u32 tRPpb;
+	u32 tRCD;
+	u32 tRC;
+	u32 tRAS;
+	u32 tWTR;
+	u32 tWR;
+	u32 tRTP;
+	u32 tW2W_C2C;
+	u32 tR2R_C2C;
+	u32 tWL;
+	u32 tDQSCK;
+	u32 tRL;
+	u32 tFAW;
+	u32 tXSR;
+	u32 tXP;
+	u32 tCKE;
+	u32 tCKESR;
+	u32 tMRD;
+};
+
 #endif /* __JEDEC_DDR_H */
diff --git a/drivers/memory/of_memory.c b/drivers/memory/of_memory.c
index 46539b27a3fb..4f5b8c81669f 100644
--- a/drivers/memory/of_memory.c
+++ b/drivers/memory/of_memory.c
@@ -3,6 +3,12 @@
  * OpenFirmware helpers for memory drivers
  *
  * Copyright (C) 2012 Texas Instruments, Inc.
+ * Copyright (C) 2019 Samsung Electronics Co., Ltd.
+ *
+ * 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>
@@ -149,3 +155,151 @@ const struct lpddr2_timings *of_get_ddr_timings(struct device_node *np_ddr,
 	return lpddr2_jedec_timings;
 }
 EXPORT_SYMBOL(of_get_ddr_timings);
+
+/**
+ * of_lpddr3_get_min_tck() - extract min timing values for lpddr3
+ * @np: pointer to ddr device tree node
+ * @device: device requesting for min timing values
+ *
+ * Populates the lpddr3_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 NULL.
+ */
+const struct lpddr3_min_tck *of_lpddr3_get_min_tck(struct device_node *np,
+						   struct device *dev)
+{
+	int			ret = 0;
+	struct lpddr3_min_tck	*min;
+
+	min = devm_kzalloc(dev, sizeof(*min), GFP_KERNEL);
+	if (!min)
+		goto default_min_tck;
+
+	ret |= of_property_read_u32(np, "tRFC-min-tck", &min->tRFC);
+	ret |= of_property_read_u32(np, "tRRD-min-tck", &min->tRRD);
+	ret |= of_property_read_u32(np, "tRPab-min-tck", &min->tRPab);
+	ret |= of_property_read_u32(np, "tRPpb-min-tck", &min->tRPpb);
+	ret |= of_property_read_u32(np, "tRCD-min-tck", &min->tRCD);
+	ret |= of_property_read_u32(np, "tRC-min-tck", &min->tRC);
+	ret |= of_property_read_u32(np, "tRAS-min-tck", &min->tRAS);
+	ret |= of_property_read_u32(np, "tWTR-min-tck", &min->tWTR);
+	ret |= of_property_read_u32(np, "tWR-min-tck", &min->tWR);
+	ret |= of_property_read_u32(np, "tRTP-min-tck", &min->tRTP);
+	ret |= of_property_read_u32(np, "tW2W-C2C-min-tck", &min->tW2W_C2C);
+	ret |= of_property_read_u32(np, "tR2R-C2C-min-tck", &min->tR2R_C2C);
+	ret |= of_property_read_u32(np, "tWL-min-tck", &min->tWL);
+	ret |= of_property_read_u32(np, "tDQSCK-min-tck", &min->tDQSCK);
+	ret |= of_property_read_u32(np, "tRL-min-tck", &min->tRL);
+	ret |= of_property_read_u32(np, "tFAW-min-tck", &min->tFAW);
+	ret |= of_property_read_u32(np, "tXSR-min-tck", &min->tXSR);
+	ret |= of_property_read_u32(np, "tXP-min-tck", &min->tXP);
+	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, "tMRD-min-tck", &min->tMRD);
+
+	if (ret) {
+		dev_warn(dev, "%s: errors while parsing min-tck values\n",
+			 __func__);
+		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 NULL;
+}
+EXPORT_SYMBOL(of_lpddr3_get_min_tck);
+
+static int of_lpddr3_do_get_timings(struct device_node *np,
+				    struct lpddr3_timings *tim)
+{
+	int ret;
+
+	/* The 'reg' param required since DT has changed, used as 'max-freq' */
+	ret = of_property_read_u32(np, "reg", &tim->max_freq);
+	ret |= of_property_read_u32(np, "min-freq", &tim->min_freq);
+	ret |= of_property_read_u32(np, "tRFC", &tim->tRFC);
+	ret |= of_property_read_u32(np, "tRRD", &tim->tRRD);
+	ret |= of_property_read_u32(np, "tRPab", &tim->tRPab);
+	ret |= of_property_read_u32(np, "tRPpb", &tim->tRPpb);
+	ret |= of_property_read_u32(np, "tRCD", &tim->tRCD);
+	ret |= of_property_read_u32(np, "tRC", &tim->tRC);
+	ret |= of_property_read_u32(np, "tRAS", &tim->tRAS);
+	ret |= of_property_read_u32(np, "tWTR", &tim->tWTR);
+	ret |= of_property_read_u32(np, "tWR", &tim->tWR);
+	ret |= of_property_read_u32(np, "tRTP", &tim->tRTP);
+	ret |= of_property_read_u32(np, "tW2W-C2C", &tim->tW2W_C2C);
+	ret |= of_property_read_u32(np, "tR2R-C2C", &tim->tR2R_C2C);
+	ret |= of_property_read_u32(np, "tFAW", &tim->tFAW);
+	ret |= of_property_read_u32(np, "tXSR", &tim->tXSR);
+	ret |= of_property_read_u32(np, "tXP", &tim->tXP);
+	ret |= of_property_read_u32(np, "tCKE", &tim->tCKE);
+	ret |= of_property_read_u32(np, "tCKESR", &tim->tCKESR);
+	ret |= of_property_read_u32(np, "tMRD", &tim->tMRD);
+
+	return ret;
+}
+
+/**
+ * of_lpddr3_get_ddr_timings() - extracts the lpddr3 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
+ * @nr_frequencies: No of frequencies available for ddr
+ * (updated by this function)
+ *
+ * Populates lpddr3_timings structure by extracting data from device
+ * tree node. Returns pointer to populated structure. If any error
+ * while populating, returns NULL.
+ */
+const struct lpddr3_timings
+*of_lpddr3_get_ddr_timings(struct device_node *np_ddr, struct device *dev,
+			   u32 device_type, u32 *nr_frequencies)
+{
+	struct lpddr3_timings	*timings = NULL;
+	u32			arr_sz = 0, i = 0;
+	struct device_node	*np_tim;
+	char			*tim_compat = NULL;
+
+	switch (device_type) {
+	case DDR_TYPE_LPDDR3:
+		tim_compat = "jedec,lpddr3-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_kcalloc(dev, arr_sz, sizeof(*timings),
+				       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_lpddr3_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 = 0;
+	return NULL;
+}
+EXPORT_SYMBOL(of_lpddr3_get_ddr_timings);
diff --git a/drivers/memory/of_memory.h b/drivers/memory/of_memory.h
index b077cc836b0b..e39ecc4c733d 100644
--- a/drivers/memory/of_memory.h
+++ b/drivers/memory/of_memory.h
@@ -14,6 +14,11 @@ extern const struct lpddr2_min_tck *of_get_min_tck(struct device_node *np,
 extern const struct lpddr2_timings
 	*of_get_ddr_timings(struct device_node *np_ddr, struct device *dev,
 	u32 device_type, u32 *nr_frequencies);
+extern const struct lpddr3_min_tck
+	*of_lpddr3_get_min_tck(struct device_node *np, struct device *dev);
+extern const struct lpddr3_timings
+	*of_lpddr3_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)
@@ -27,6 +32,19 @@ static inline const struct lpddr2_timings
 {
 	return NULL;
 }
+
+static inline const struct lpddr3_min_tck
+	*of_lpddr3_get_min_tck(struct device_node *np, struct device *dev)
+{
+	return NULL;
+}
+
+static inline const struct lpddr3_timings
+	*of_lpddr3_get_ddr_timings(struct device_node *np_ddr,
+	struct device *dev, u32 device_type, u32 *nr_frequencies)
+{
+	return NULL;
+}
 #endif /* CONFIG_OF && CONFIG_DDR */
 
 #endif /* __LINUX_MEMORY_OF_REG_ */
-- 
2.17.1