[PATCH v1] lib:platform: Add support for specify coldboot harts in DT for generic.

[Cheng Yang]

Added support for the generic platform to specify the set of coldboot
hart in DT. If not specified in DT, all harts are allowed to coldboot
as before.

The functions related to sbi_hartmask are not available before coldboot,
so I used bitmap, and added a new bitmap_test() function to test whether
a certain bit of the bitmap is set.

Signed-off-by: Cheng Yang <yangcheng.work at foxmail.com>
---
 include/sbi/sbi_bitmap.h    |  5 +++
 lib/utils/fdt/fdt_fixup.c   | 18 ++++++++++
 platform/generic/platform.c | 71 ++++++++++++++++++++++++++++++++++++-
 3 files changed, 93 insertions(+), 1 deletion(-)

diff --git a/include/sbi/sbi_bitmap.h b/include/sbi/sbi_bitmap.h
index 4f0ebb6..354476c 100644
--- a/include/sbi/sbi_bitmap.h
+++ b/include/sbi/sbi_bitmap.h
@@ -62,6 +62,11 @@ static inline void bitmap_zero(unsigned long *dst, int nbits)
 	}
 }
 
+static inline int bitmap_test(unsigned long *bmap, int bit)
+{
+	return __test_bit(bit, bmap);
+}
+
 static inline void bitmap_zero_except(unsigned long *dst,
 				      int exception, int nbits)
 {
diff --git a/lib/utils/fdt/fdt_fixup.c b/lib/utils/fdt/fdt_fixup.c
index 5fc7673..0d0df2c 100644
--- a/lib/utils/fdt/fdt_fixup.c
+++ b/lib/utils/fdt/fdt_fixup.c
@@ -385,6 +385,22 @@ int fdt_reserved_memory_fixup(void *fdt)
 	return 0;
 }
 
+void fdt_config_fixup(void *fdt) {
+	int chosen_offset, config_offset;
+
+	chosen_offset = fdt_path_offset(fdt, "/chosen");
+	if (chosen_offset < 0) {
+		return;
+	}
+
+	config_offset = fdt_node_offset_by_compatible(fdt, chosen_offset, "opensbi,config");
+	if (chosen_offset < 0) {
+		return;
+	}
+
+	fdt_nop_node(fdt, config_offset);
+}
+
 void fdt_fixups(void *fdt)
 {
 	fdt_aplic_fixup(fdt);
@@ -398,4 +414,6 @@ void fdt_fixups(void *fdt)
 #ifndef CONFIG_FDT_FIXUPS_PRESERVE_PMU_NODE
 	fdt_pmu_fixup(fdt);
 #endif
+
+	fdt_config_fixup(fdt);
 }
diff --git a/platform/generic/platform.c b/platform/generic/platform.c
index bfd7d31..edd4050 100644
--- a/platform/generic/platform.c
+++ b/platform/generic/platform.c
@@ -73,6 +73,66 @@ extern struct sbi_platform platform;
 static bool platform_has_mlevel_imsic = false;
 static u32 generic_hart_index2id[SBI_HARTMASK_MAX_BITS] = { 0 };
 
+DECLARE_BITMAP(generic_coldboot_harts, SBI_HARTMASK_MAX_BITS);
+
+/*
+ * The fw_platform_coldboot_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" 
+ * DT node. If there is no "cold-boot-harts" in DT, all harts will be allowed.
+ */
+static void fw_platform_coldboot_init(void *fdt)
+{
+	int chosen_offset, config_offset, cpu_offset, len, err;
+	u32 val32;
+	const u32 *val;
+
+	bitmap_zero(generic_coldboot_harts, SBI_HARTMASK_MAX_BITS);
+
+	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 = fdt_getprop(fdt, config_offset, "cold-boot-harts", &len);
+	len = len / sizeof(u32);
+	if (val && len) {
+		for (int i = 0; i < len; i++) {
+			cpu_offset = fdt_node_offset_by_phandle(fdt,
+							fdt32_to_cpu(val[i]));
+			if (cpu_offset < 0) {
+				goto default_config;
+			}
+
+			err = fdt_parse_hart_id(fdt, cpu_offset, &val32);
+			if (err) {
+				goto default_config;
+			}
+
+			if (!fdt_node_is_enabled(fdt, cpu_offset))
+				continue;
+
+			for (int i = 0; i < platform.hart_count; i++) {
+				if (val32 == generic_hart_index2id[i]) {
+					bitmap_set(generic_coldboot_harts, i, 1);
+				}
+			}
+
+		}
+	}
+
+	return;
+
+default_config:
+	bitmap_fill(generic_coldboot_harts, SBI_HARTMASK_MAX_BITS);
+	return;
+}
+
 /*
  * The fw_platform_init() function is called very early on the boot HART
  * OpenSBI reference firmwares so that platform specific code get chance
@@ -133,6 +193,8 @@ unsigned long fw_platform_init(unsigned long arg0, unsigned long arg1,
 	platform.heap_size = fw_platform_calculate_heap_size(hart_count);
 	platform_has_mlevel_imsic = fdt_check_imsic_mlevel(fdt);
 
+	fw_platform_coldboot_init(fdt);
+
 	/* Return original FDT pointer */
 	return arg1;
 
@@ -146,7 +208,14 @@ static bool generic_cold_boot_allowed(u32 hartid)
 	if (generic_plat && generic_plat->cold_boot_allowed)
 		return generic_plat->cold_boot_allowed(
 						hartid, generic_plat_match);
-	return true;
+
+	for (int i = 0; i < platform.hart_count; i++) {
+		if (hartid == generic_hart_index2id[i]) {
+			return bitmap_test(generic_coldboot_harts, i);
+		}
+	}
+
+	return false;
 }
 
 static int generic_nascent_init(void)
-- 
2.34.1