arm-trusted-firmware/include/common/fdt_wrappers.h

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/*
* Copyright (c) 2018-2020, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
/* Helper functions to offer easier navigation of Device Tree Blob */
#ifndef FDT_WRAPPERS_H
#define FDT_WRAPPERS_H
/* Number of cells, given total length in bytes. Each cell is 4 bytes long */
#define NCELLS(len) ((len) / 4U)
fdt/wrappers: Replace fdtw_read_cells() implementation Our fdtw_read_cells() implementation goes to great lengths to sanity-check every parameter and result, but leaves a big hole open: The size of the storage the value pointer points at needs to match the number of cells given. This can't be easily checked at compile time, since we lose the size information by using a void pointer. Regardless the current usage of this function is somewhat wrong anyways, since we use it on single-element, fixed-length properties only, for which the DT binding specifies the size. Typically we use those functions dealing with a number of cells in DT context to deal with *dynamically* sized properties, which depend on other properties (#size-cells, #clock-cells, ...), to specify the number of cells needed. Another problem with the current implementation is the use of ambiguously sized types (uintptr_t, size_t) together with a certain expectation about their size. In general there is no relation between the length of a DT property and the bitness of the code that parses the DTB: AArch64 code could encounter 32-bit addresses (where the physical address space is limited to 4GB [1]), while AArch32 code could read 64-bit sized properties (/memory nodes on LPAE systems, [2]). To make this more clear, fix the potential issues and also align more with other DT users (Linux and U-Boot), introduce functions to explicitly read uint32 and uint64 properties. As the other DT consumers, we do this based on the generic "read array" function. Convert all users to use either of those two new functions, and make sure we never use a pointer to anything other than uint32_t or uint64_t variables directly. This reveals (and fixes) a bug in plat_spmd_manifest.c, where we write 4 bytes into a uint16_t variable (passed via a void pointer). Also we change the implementation of the function to better align with other libfdt users, by using the right types (fdt32_t) and common variable names (*prop, prop_names). [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi#n874 [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/ecx-2000.dts Change-Id: I718de960515117ac7a3331a1b177d2ec224a3890 Signed-off-by: Andre Przywara <andre.przywara@arm.com>
2020-03-26 11:22:37 +00:00
int fdt_read_uint32(const void *dtb, int node, const char *prop_name,
uint32_t *value);
uint32_t fdt_read_uint32_default(const void *dtb, int node,
const char *prop_name, uint32_t dflt_value);
fdt/wrappers: Replace fdtw_read_cells() implementation Our fdtw_read_cells() implementation goes to great lengths to sanity-check every parameter and result, but leaves a big hole open: The size of the storage the value pointer points at needs to match the number of cells given. This can't be easily checked at compile time, since we lose the size information by using a void pointer. Regardless the current usage of this function is somewhat wrong anyways, since we use it on single-element, fixed-length properties only, for which the DT binding specifies the size. Typically we use those functions dealing with a number of cells in DT context to deal with *dynamically* sized properties, which depend on other properties (#size-cells, #clock-cells, ...), to specify the number of cells needed. Another problem with the current implementation is the use of ambiguously sized types (uintptr_t, size_t) together with a certain expectation about their size. In general there is no relation between the length of a DT property and the bitness of the code that parses the DTB: AArch64 code could encounter 32-bit addresses (where the physical address space is limited to 4GB [1]), while AArch32 code could read 64-bit sized properties (/memory nodes on LPAE systems, [2]). To make this more clear, fix the potential issues and also align more with other DT users (Linux and U-Boot), introduce functions to explicitly read uint32 and uint64 properties. As the other DT consumers, we do this based on the generic "read array" function. Convert all users to use either of those two new functions, and make sure we never use a pointer to anything other than uint32_t or uint64_t variables directly. This reveals (and fixes) a bug in plat_spmd_manifest.c, where we write 4 bytes into a uint16_t variable (passed via a void pointer). Also we change the implementation of the function to better align with other libfdt users, by using the right types (fdt32_t) and common variable names (*prop, prop_names). [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi#n874 [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/ecx-2000.dts Change-Id: I718de960515117ac7a3331a1b177d2ec224a3890 Signed-off-by: Andre Przywara <andre.przywara@arm.com>
2020-03-26 11:22:37 +00:00
int fdt_read_uint64(const void *dtb, int node, const char *prop_name,
uint64_t *value);
int fdt_read_uint32_array(const void *dtb, int node, const char *prop_name,
unsigned int cells, uint32_t *value);
int fdtw_read_string(const void *dtb, int node, const char *prop,
char *str, size_t size);
int fdtw_write_inplace_cells(void *dtb, int node, const char *prop,
unsigned int cells, void *value);
int fdtw_read_bytes(const void *dtb, int node, const char *prop,
unsigned int length, void *value);
int fdtw_write_inplace_bytes(void *dtb, int node, const char *prop,
unsigned int length, const void *data);
int fdt_get_reg_props_by_index(const void *dtb, int node, int index,
uintptr_t *base, size_t *size);
#endif /* FDT_WRAPPERS_H */