[PATCH v3 01/19] lib: fdtdec: Handle multiple memory nodes

From: Jiaxun Yang <[email protected]>

Current code only tries to fetch the first memory node found in
fdt tree and determine memory banks from multiple reg properties.

Specification allows multiple memory nodes in devicetree, rework
fdtdec_setup_mem_size_base_lowest and fdtdec_setup_memory_banksize
to iterate over all memory nodes.

Signed-off-by: Jiaxun Yang <[email protected]>
Signed-off-by: Yao Zi <[email protected]>
---

Changed from v2
- Return directly from the inner loop of fdtdec_setup_memory_banksize(),
  instead of using a goto
- Use %pap instead of %llx when appropriate
- Use phys_addr_t for base in fdtdec_get_next_memory_node()

Changed from v1
- Reword commit message to reflect the fact that dtspec allows multiple
  memory nodes
- Replace sort_memory_banks() with qsort()
- Do not use CONFIG_VAL when referencing NR_DRAM_BANKS to avoid breaking
  SPL build
- print gd->ram_size with %pap instead of %lx, drop unnecessary cast for
  gd->ram_base in fdtdec_setup_size_base_lowest()
- Style improvements

 include/asm-generic/global_data.h |   2 +-
 lib/fdtdec.c                      | 127 +++++++++++++++++-------------
 2 files changed, 74 insertions(+), 55 deletions(-)

diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
index 886c12900ddb..75c80c8a0db4 100644
--- a/include/asm-generic/global_data.h
+++ b/include/asm-generic/global_data.h
@@ -462,7 +462,7 @@ struct global_data {
 	/**
 	 * @dram: array describing DRAM banks (start address and size for each bank)
 	 */
-	struct {			/* RAM configuration */
+	struct dram_bank {		/* RAM configuration */
 		phys_addr_t start;
 		phys_size_t size;
 	} dram[CONFIG_NR_DRAM_BANKS];
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index b91e067106dd..dfc30bdb8f85 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -36,6 +36,7 @@
 #include <linux/lzo.h>
 #include <linux/ioport.h>
 #include <asm/global_data.h>
+#include <sort.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -1115,90 +1116,108 @@ ofnode fdtdec_get_next_memory_node(ofnode mem)
 	return get_next_memory_node(mem);
 }
 
+static int cmp_memory_bank(const void *a, const void *b)
+{
+	const struct dram_bank *a1 = a, *b1 = b;
+
+	return a1->start > b1->start ? 1 :
+	       a1->start < b1->start ? -1 : 0;
+}
+
 int fdtdec_setup_memory_banksize(void)
 {
-	int bank, ret, reg = 0;
-	struct resource res;
+	int bank = 0;
 	ofnode mem = ofnode_null();
 
-	mem = get_next_memory_node(mem);
-	if (!ofnode_valid(mem)) {
-		debug("%s: Missing /memory node\n", __func__);
-		return -EINVAL;
-	}
+	while (true) {
+		struct resource res;
+		int reg = 0;
 
-	for (bank = 0; bank < CONFIG_NR_DRAM_BANKS; bank++) {
-		ret = ofnode_read_resource(mem, reg++, &res);
-		if (ret < 0) {
-			reg = 0;
-			mem = get_next_memory_node(mem);
-			if (!ofnode_valid(mem))
-				break;
+		mem = get_next_memory_node(mem);
+		if (!ofnode_valid(mem))
+			break;
+
+		while (true) {
+			int ret = ofnode_read_resource(mem, reg, &res);
 
-			ret = ofnode_read_resource(mem, reg++, &res);
 			if (ret < 0)
 				break;
-		}
 
-		if (ret != 0)
-			return -EINVAL;
+			if (bank >= CONFIG_NR_DRAM_BANKS) {
+				log_warning("%s: Too many memory banks\n", __func__);
+				return -EINVAL;
+			}
 
-		gd->dram[bank].start = (phys_addr_t)res.start;
-		gd->dram[bank].size =
-			(phys_size_t)(res.end - res.start + 1);
+			gd->dram[bank].start = res.start;
+			gd->dram[bank].size =
+					(phys_size_t)(res.end - res.start + 1);
 
-		debug("%s: DRAM Bank #%d: start = %pap, size = %pap\n",
-		      __func__, bank,
-		      &gd->dram[bank].start,
-		      &gd->dram[bank].size);
+			log_debug("%s: DRAM Bank #%d %s.%d: start = 0x%pap, size = 0x%pap\n",
+				  __func__, bank, ofnode_get_name(mem), reg,
+				  &gd->dram[bank].start, &gd->dram[bank].size);
+			reg++;
+			bank++;
+		}
 	}
 
+	if (!bank) {
+		log_warning("%s: Missing /memory node\n", __func__);
+		return -EINVAL;
+	}
+
+	qsort(gd->dram, bank, sizeof(gd->dram[0]), cmp_memory_bank);
+
 	return 0;
 }
 
 int fdtdec_setup_mem_size_base_lowest(void)
 {
-	int bank, ret, reg = 0;
-	struct resource res;
-	unsigned long base;
-	phys_size_t size;
+	int bank = 0;
 	ofnode mem = ofnode_null();
+	__maybe_unused const char *final_name;
+	__maybe_unused int final_reg;
 
-	gd->ram_base = (unsigned long)~0;
+	gd->ram_base = ULONG_MAX;
 
-	mem = get_next_memory_node(mem);
-	if (!ofnode_valid(mem)) {
-		debug("%s: Missing /memory node\n", __func__);
-		return -EINVAL;
-	}
+	while (true) {
+		struct resource res;
+		phys_addr_t base;
+		phys_size_t size;
+		int reg = 0;
 
-	for (bank = 0; bank < CONFIG_NR_DRAM_BANKS; bank++) {
-		ret = ofnode_read_resource(mem, reg++, &res);
-		if (ret < 0) {
-			reg = 0;
-			mem = get_next_memory_node(mem);
-			if (!ofnode_valid(mem))
-				break;
+		mem = get_next_memory_node(mem);
+		if (!ofnode_valid(mem))
+			break;
+
+		while (true) {
+			int ret = ofnode_read_resource(mem, reg, &res);
 
-			ret = ofnode_read_resource(mem, reg++, &res);
 			if (ret < 0)
 				break;
-		}
 
-		if (ret != 0)
-			return -EINVAL;
-
-		base = (unsigned long)res.start;
-		size = (phys_size_t)(res.end - res.start + 1);
+			base = res.start;
+			size = res.end - res.start + 1;
+			if (gd->ram_base > base && size) {
+				gd->ram_base = base;
+				gd->ram_size = size;
+				final_name = ofnode_get_name(mem);
+				final_reg = reg;
+			}
 
-		if (gd->ram_base > base && size) {
-			gd->ram_base = base;
-			gd->ram_size = size;
-			debug("%s: Initial DRAM base %lx size %lx\n",
-			      __func__, base, (unsigned long)size);
+			reg++;
+			bank++;
 		}
 	}
 
+	if (!bank) {
+		log_warning("%s: Missing /memory node\n", __func__);
+		return -EINVAL;
+	}
+
+	log_debug("%s: Initial DRAM %s.%d: base %lx size %pap\n",
+		  __func__, final_name, final_reg,
+		  gd->ram_base, &gd->ram_size);
+
 	return 0;
 }
 
-- 
2.55.0