[PATCH v15 06/16] of/fdt: add helper functions for handling properties

From: AKASHI Takahiro
Date: Fri Sep 28 2018 - 02:48:26 EST


These functions will be used later to handle kexec-specific properties
in arm64's kexec_file implementation.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: Frank Rowand <frowand.list@xxxxxxxxx>
Cc: devicetree@xxxxxxxxxxxxxxx
---
drivers/of/fdt.c | 56 ++++++++++++++++++++++++++++++++++++++++++
include/linux/of_fdt.h | 4 +++
2 files changed, 60 insertions(+)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 800ad252cf9c..c65c31562ccb 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -25,6 +25,7 @@
#include <linux/debugfs.h>
#include <linux/serial_core.h>
#include <linux/sysfs.h>
+#include <linux/types.h>

#include <asm/setup.h> /* for COMMAND_LINE_SIZE */
#include <asm/page.h>
@@ -1323,3 +1324,58 @@ late_initcall(of_fdt_raw_init);
#endif

#endif /* CONFIG_OF_EARLY_FLATTREE */
+
+#define FDT_ALIGN(x, a) (((x) + (a) - 1) & ~((a) - 1))
+#define FDT_TAGALIGN(x) (FDT_ALIGN((x), FDT_TAGSIZE))
+
+int fdt_prop_len(const char *prop_name, int len)
+{
+ return (strlen(prop_name) + 1) +
+ sizeof(struct fdt_property) +
+ FDT_TAGALIGN(len);
+}
+
+static void fill_property(void *buf, u64 val64, int cells)
+{
+ __be32 val32;
+
+ while (cells) {
+ val32 = cpu_to_fdt32((val64 >> (32 * (--cells))) & U32_MAX);
+ memcpy(buf, &val32, sizeof(val32));
+ buf += sizeof(val32);
+ }
+}
+
+int fdt_setprop_reg(void *fdt, int nodeoffset, const char *name,
+ u64 addr, u64 size)
+{
+ int addr_cells, size_cells;
+ char buf[sizeof(__be32) * 2 * 2];
+ /* assume dt_root_[addr|size]_cells <= 2 */
+ void *prop;
+ size_t buf_size;
+
+ addr_cells = fdt_address_cells(fdt, 0);
+ if (addr_cells < 0)
+ return addr_cells;
+ size_cells = fdt_size_cells(fdt, 0);
+ if (size_cells < 0)
+ return size_cells;
+
+ /* if *_cells >= 2, cells can hold 64-bit values anyway */
+ if ((addr_cells == 1) && (addr > U32_MAX))
+ return -FDT_ERR_BADVALUE;
+
+ if ((size_cells == 1) && (size > U32_MAX))
+ return -FDT_ERR_BADVALUE;
+
+ buf_size = (addr_cells + size_cells) * sizeof(u32);
+ prop = buf;
+
+ fill_property(prop, addr, addr_cells);
+ prop += addr_cells * sizeof(u32);
+
+ fill_property(prop, size, size_cells);
+
+ return fdt_setprop(fdt, nodeoffset, name, buf, buf_size);
+}
diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index b9cd9ebdf9b9..842af6ea92ea 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -108,5 +108,9 @@ static inline void unflatten_device_tree(void) {}
static inline void unflatten_and_copy_device_tree(void) {}
#endif /* CONFIG_OF_EARLY_FLATTREE */

+int fdt_prop_len(const char *prop_name, int len);
+int fdt_setprop_reg(void *fdt, int nodeoffset, const char *name,
+ u64 addr, u64 size);
+
#endif /* __ASSEMBLY__ */
#endif /* _LINUX_OF_FDT_H */
--
2.19.0