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SubjectRe: [PATCH v16 06/16] lib: fdt: add a helper function for handling memory range property
[moving some DT people to TO:]

On Thu, Nov 15, 2018 at 02:52:45PM +0900, AKASHI Takahiro wrote:
> Added function, fdt_setprop_reg(), will be used later to handle
> kexec-specific property in arm64's kexec_file implementation.
> It will possibly be merged into libfdt in the future.
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Frank Rowand <frowand.list@gmail.com>
> Cc: devicetree@vger.kernel.org
> ---
> include/linux/libfdt.h | 26 ++++++++++++++++++++
> lib/Makefile | 2 +-
> lib/fdt_addresses.c | 56 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 83 insertions(+), 1 deletion(-)
> create mode 100644 lib/fdt_addresses.c

We need an ack from the DT side before we can merge this series, please.

Will

> diff --git a/include/linux/libfdt.h b/include/linux/libfdt.h
> index 90ed4ebfa692..47c4dc9e135c 100644
> --- a/include/linux/libfdt.h
> +++ b/include/linux/libfdt.h
> @@ -5,4 +5,30 @@
> #include <linux/libfdt_env.h>
> #include "../../scripts/dtc/libfdt/libfdt.h"
>
> +/**
> + * fdt_setprop_reg - add/set a memory region property
> + * @fdt: pointer to the device tree blob
> + * @nodeoffset: offset of the node to add a property at
> + * @name: name of property
> + * @addr: physical start address
> + * @size: size of region
> + *
> + * returns:
> + * 0, on success
> + * -FDT_ERR_BADLAYOUT,
> + * -FDT_ERR_BADMAGIC,
> + * -FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
> + * #address-cells property
> + * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
> + * -FDT_ERR_BADSTATE,
> + * -FDT_ERR_BADSTRUCTURE,
> + * -FDT_ERR_BADVERSION,
> + * -FDT_ERR_BADVALUE, addr or size doesn't fit to respective cells size
> + * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
> + * contain a new property
> + * -FDT_ERR_TRUNCATED, standard meanings
> + */
> +int fdt_setprop_reg(void *fdt, int nodeoffset, const char *name,
> + u64 addr, u64 size);
> +
> #endif /* _INCLUDE_LIBFDT_H_ */
> diff --git a/lib/Makefile b/lib/Makefile
> index db06d1237898..2a96cb05e15d 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -205,7 +205,7 @@ KASAN_SANITIZE_stackdepot.o := n
> KCOV_INSTRUMENT_stackdepot.o := n
>
> libfdt_files = fdt.o fdt_ro.o fdt_wip.o fdt_rw.o fdt_sw.o fdt_strerror.o \
> - fdt_empty_tree.o
> + fdt_empty_tree.o fdt_addresses.o
> $(foreach file, $(libfdt_files), \
> $(eval CFLAGS_$(file) = -I$(src)/../scripts/dtc/libfdt))
> lib-$(CONFIG_LIBFDT) += $(libfdt_files)
> diff --git a/lib/fdt_addresses.c b/lib/fdt_addresses.c
> new file mode 100644
> index 000000000000..97ddd5a5cc10
> --- /dev/null
> +++ b/lib/fdt_addresses.c
> @@ -0,0 +1,56 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <linux/libfdt_env.h>
> +#include <linux/types.h>
> +#include "../scripts/dtc/libfdt/fdt_addresses.c"
> +
> +/*
> + * helper functions for arm64 kexec
> + * Those functions may be merged into libfdt in the future.
> + */
> +
> +/* This function assumes that cells is 1 or 2 */
> +static void cpu64_to_fdt_cells(void *buf, u64 val64, int cells)
> +{
> + __be32 val32;
> +
> + while (cells) {
> + val32 = cpu_to_fdt32(val64 >> (32 * (--cells)));
> + 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) ||
> + ((addr + size) > 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;
> +
> + cpu64_to_fdt_cells(prop, addr, addr_cells);
> + prop += addr_cells * sizeof(u32);
> +
> + cpu64_to_fdt_cells(prop, size, size_cells);
> +
> + return fdt_setprop(fdt, nodeoffset, name, buf, buf_size);
> +}
> --
> 2.19.0
>

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