From 643e14cfa2005090a6a3a3949191f4baa7b434e7 Mon Sep 17 00:00:00 2001
From: Kaushal Kumar <kaushalk@codeaurora.org>
Date: Tue, 19 Nov 2019 19:14:20 +0530
Subject: [PATCH] ANDROID: GKI: drivers: of: Add APIs to find DDR device rank,
 HBB

Add APIs to find the DDR device rank and Highest
Bank Bit (HBB) information from their respective
memory nodes.

Bug: 153905290
Test: compile
Change-Id: Iae94efc681daf2cf0a531dceb8d2acdcf3484388
Signed-off-by: Kaushal Kumar <kaushalk@codeaurora.org>
(cherry picked from commit 789ad9a7a829c6c423125eac3490967916c46ba9)
Signed-off-by: Will McVicker <willmcvicker@google.com>
---
 drivers/of/fdt.c       | 63 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/of_fdt.h |  2 ++
 2 files changed, 65 insertions(+)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 85b0055a5ae4..688f1226eea2 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -80,6 +80,69 @@ void of_fdt_limit_memory(int limit)
 	}
 }
 
+/**
+ * of_fdt_get_ddrhbb - Return the highest bank bit of ddr on the current device
+ *
+ * On match, returns a non-zero positive value which matches the highest bank
+ * bit.
+ * Otherwise returns -ENOENT.
+ */
+int of_fdt_get_ddrhbb(int channel, int rank)
+{
+	int memory;
+	int len;
+	int ret;
+	/* Single spaces reserved for channel(0-9), rank(0-9) */
+	char pname[] = "ddr_device_hbb_ch _rank ";
+	fdt32_t *prop = NULL;
+
+	memory = fdt_path_offset(initial_boot_params, "/memory");
+	if (memory > 0) {
+		snprintf(pname, sizeof(pname),
+			 "ddr_device_hbb_ch%d_rank%d", channel, rank);
+		prop = fdt_getprop_w(initial_boot_params, memory,
+				     pname, &len);
+	}
+
+	if (!prop || len != sizeof(u32))
+		return -ENOENT;
+
+	ret = fdt32_to_cpu(*prop);
+
+	return ret;
+}
+
+/**
+ * of_fdt_get_ddrrank - Return the rank of ddr on the current device
+ *
+ * On match, returns a non-zero positive value which matches the ddr rank.
+ * Otherwise returns -ENOENT.
+ */
+int of_fdt_get_ddrrank(int channel)
+{
+	int memory;
+	int len;
+	int ret;
+	/* Single space reserved for channel(0-9) */
+	char pname[] = "ddr_device_rank_ch ";
+	fdt32_t *prop = NULL;
+
+	memory = fdt_path_offset(initial_boot_params, "/memory");
+	if (memory > 0) {
+		snprintf(pname, sizeof(pname),
+			 "ddr_device_rank_ch%d", channel);
+		prop = fdt_getprop_w(initial_boot_params, memory,
+				     pname, &len);
+	}
+
+	if (!prop || len != sizeof(u32))
+		return -ENOENT;
+
+	ret = fdt32_to_cpu(*prop);
+
+	return ret;
+}
+
 /**
  * of_fdt_get_ddrtype - Return the type of ddr (4/5) on the current device
  *
diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index f41f3c463307..280bffadd0b4 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -48,6 +48,8 @@ extern char __dtb_end[];
 extern u64 of_flat_dt_translate_address(unsigned long node);
 extern void of_fdt_limit_memory(int limit);
 extern int of_fdt_get_ddrtype(void);
+extern int of_fdt_get_ddrrank(int channel);
+extern int of_fdt_get_ddrhbb(int channel, int rank);
 #endif /* CONFIG_OF_FLATTREE */
 
 #ifdef CONFIG_OF_EARLY_FLATTREE