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![Gustavo A. R. Silva](/assets/img/avatar_default.png)
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293
("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200507192223.GA16335@embeddedor
Signed-off-by: Takashi Iwai <tiwai@suse.de>
150 lines
2.7 KiB
C
150 lines
2.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* intel-nhlt.h - Intel HDA Platform NHLT header
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*
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* Copyright (c) 2015-2019 Intel Corporation
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*/
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#ifndef __INTEL_NHLT_H__
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#define __INTEL_NHLT_H__
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#include <linux/acpi.h>
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#if IS_ENABLED(CONFIG_ACPI) && IS_ENABLED(CONFIG_SND_INTEL_NHLT)
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struct wav_fmt {
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u16 fmt_tag;
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u16 channels;
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u32 samples_per_sec;
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u32 avg_bytes_per_sec;
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u16 block_align;
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u16 bits_per_sample;
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u16 cb_size;
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} __packed;
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struct wav_fmt_ext {
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struct wav_fmt fmt;
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union samples {
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u16 valid_bits_per_sample;
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u16 samples_per_block;
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u16 reserved;
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} sample;
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u32 channel_mask;
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u8 sub_fmt[16];
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} __packed;
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enum nhlt_link_type {
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NHLT_LINK_HDA = 0,
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NHLT_LINK_DSP = 1,
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NHLT_LINK_DMIC = 2,
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NHLT_LINK_SSP = 3,
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NHLT_LINK_INVALID
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};
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enum nhlt_device_type {
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NHLT_DEVICE_BT = 0,
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NHLT_DEVICE_DMIC = 1,
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NHLT_DEVICE_I2S = 4,
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NHLT_DEVICE_INVALID
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};
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struct nhlt_specific_cfg {
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u32 size;
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u8 caps[];
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} __packed;
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struct nhlt_fmt_cfg {
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struct wav_fmt_ext fmt_ext;
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struct nhlt_specific_cfg config;
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} __packed;
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struct nhlt_fmt {
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u8 fmt_count;
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struct nhlt_fmt_cfg fmt_config[];
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} __packed;
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struct nhlt_endpoint {
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u32 length;
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u8 linktype;
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u8 instance_id;
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u16 vendor_id;
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u16 device_id;
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u16 revision_id;
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u32 subsystem_id;
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u8 device_type;
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u8 direction;
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u8 virtual_bus_id;
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struct nhlt_specific_cfg config;
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} __packed;
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struct nhlt_acpi_table {
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struct acpi_table_header header;
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u8 endpoint_count;
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struct nhlt_endpoint desc[];
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} __packed;
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struct nhlt_resource_desc {
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u32 extra;
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u16 flags;
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u64 addr_spc_gra;
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u64 min_addr;
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u64 max_addr;
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u64 addr_trans_offset;
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u64 length;
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} __packed;
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#define MIC_ARRAY_2CH 2
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#define MIC_ARRAY_4CH 4
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struct nhlt_device_specific_config {
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u8 virtual_slot;
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u8 config_type;
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} __packed;
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struct nhlt_dmic_array_config {
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struct nhlt_device_specific_config device_config;
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u8 array_type;
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} __packed;
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struct nhlt_vendor_dmic_array_config {
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struct nhlt_dmic_array_config dmic_config;
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u8 nb_mics;
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/* TODO add vendor mic config */
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} __packed;
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enum {
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NHLT_MIC_ARRAY_2CH_SMALL = 0xa,
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NHLT_MIC_ARRAY_2CH_BIG = 0xb,
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NHLT_MIC_ARRAY_4CH_1ST_GEOM = 0xc,
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NHLT_MIC_ARRAY_4CH_L_SHAPED = 0xd,
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NHLT_MIC_ARRAY_4CH_2ND_GEOM = 0xe,
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NHLT_MIC_ARRAY_VENDOR_DEFINED = 0xf,
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};
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struct nhlt_acpi_table *intel_nhlt_init(struct device *dev);
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void intel_nhlt_free(struct nhlt_acpi_table *addr);
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int intel_nhlt_get_dmic_geo(struct device *dev, struct nhlt_acpi_table *nhlt);
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#else
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struct nhlt_acpi_table;
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static inline struct nhlt_acpi_table *intel_nhlt_init(struct device *dev)
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{
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return NULL;
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}
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static inline void intel_nhlt_free(struct nhlt_acpi_table *addr)
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{
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}
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static inline int intel_nhlt_get_dmic_geo(struct device *dev,
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struct nhlt_acpi_table *nhlt)
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{
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return 0;
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}
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#endif
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#endif
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