platform: introduce DT-based configurable heap size

The default heap size will work for most platforms, but for some
special platforms, the heap is too small to hold all the information
or is too big so that it take too much ram. Introduce configurable
heap should solve this problem and make all generic platforms happy.

Add DT-based heap-size for the generic platform.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Reviewed-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>

docs/opensbi_config.md

@@ -23,6 +23,9 @@ The DT properties of a domain configuration DT node are as follows:
   set of harts is permitted to perform a cold boot. Otherwise, all
   harts are allowed to cold boot.
 
+* **heap-size** (Optional) - When present, the specified value is used
+  as the size of the heap in bytes.
+
 * **system-suspend-test** (Optional) - When present, enable a system
   suspend test implementation which simply waits five seconds and issues a WFI.
 
@@ -36,6 +39,7 @@ The OpenSBI Configuration Node will be deleted at the end of cold boot
         opensbi-config {
             compatible = "opensbi,config";
             cold-boot-harts = <&cpu1 &cpu2 &cpu3 &cpu4>;
+            heap-size = <0x400000>;
             system-suspend-test;
         };
     };

platform/generic/platform.c

@@ -69,6 +69,28 @@ static u32 fw_platform_calculate_heap_size(u32 hart_count)
 	return BIT_ALIGN(heap_size, HEAP_BASE_ALIGN);
 }
 
+static u32 fw_platform_get_heap_size(const void *fdt, u32 hart_count)
+{
+	int chosen_offset, config_offset, len;
+	const fdt32_t *val;
+
+	/* Get the heap size from device tree */
+	chosen_offset = fdt_path_offset(fdt, "/chosen");
+	if (chosen_offset < 0)
+		goto default_config;
+
+	config_offset = fdt_node_offset_by_compatible(fdt, chosen_offset, "opensbi,config");
+	if (config_offset < 0)
+		goto default_config;
+
+	val = (fdt32_t *)fdt_getprop(fdt, config_offset, "heap-size", &len);
+	if (len > 0 && val)
+		return BIT_ALIGN(fdt32_to_cpu(*val), HEAP_BASE_ALIGN);
+
+default_config:
+	return fw_platform_calculate_heap_size(hart_count);
+}
+
 extern struct sbi_platform platform;
 static bool platform_has_mlevel_imsic = false;
 static u32 generic_hart_index2id[SBI_HARTMASK_MAX_BITS] = { 0 };
@@ -76,9 +98,9 @@ static u32 generic_hart_index2id[SBI_HARTMASK_MAX_BITS] = { 0 };
 static DECLARE_BITMAP(generic_coldboot_harts, SBI_HARTMASK_MAX_BITS);
 
 /*
- * The fw_platform_coldboot_harts_init() function is called by fw_platform_init() 
+ * The fw_platform_coldboot_harts_init() function is called by fw_platform_init()
  * function to initialize the cold boot harts allowed by the generic platform
- * according to the DT property "cold-boot-harts" in "/chosen/opensbi-config" 
+ * according to the DT property "cold-boot-harts" in "/chosen/opensbi-config"
  * DT node. If there is no "cold-boot-harts" in DT, all harts will be allowed.
  */
 static void fw_platform_coldboot_harts_init(const void *fdt)
@@ -185,7 +207,7 @@ unsigned long fw_platform_init(unsigned long arg0, unsigned long arg1,
 	}
 
 	platform.hart_count = hart_count;
-	platform.heap_size = fw_platform_calculate_heap_size(hart_count);
+	platform.heap_size = fw_platform_get_heap_size(fdt, hart_count);
 	platform_has_mlevel_imsic = fdt_check_imsic_mlevel(fdt);
 
 	fw_platform_coldboot_harts_init(fdt);