linux/include/sound/intel-nhlt.h
Gustavo A. R. Silva 9ad06ebb9a ALSA: Replace zero-length array with flexible-array
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>
2020-05-07 22:30:36 +02:00

151 lines
2.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* intel-nhlt.h - Intel HDA Platform NHLT header
*
* Copyright (c) 2015-2019 Intel Corporation
*/
#ifndef __INTEL_NHLT_H__
#define __INTEL_NHLT_H__
#include <linux/acpi.h>
#if IS_ENABLED(CONFIG_ACPI) && IS_ENABLED(CONFIG_SND_INTEL_NHLT)
struct wav_fmt {
u16 fmt_tag;
u16 channels;
u32 samples_per_sec;
u32 avg_bytes_per_sec;
u16 block_align;
u16 bits_per_sample;
u16 cb_size;
} __packed;
struct wav_fmt_ext {
struct wav_fmt fmt;
union samples {
u16 valid_bits_per_sample;
u16 samples_per_block;
u16 reserved;
} sample;
u32 channel_mask;
u8 sub_fmt[16];
} __packed;
enum nhlt_link_type {
NHLT_LINK_HDA = 0,
NHLT_LINK_DSP = 1,
NHLT_LINK_DMIC = 2,
NHLT_LINK_SSP = 3,
NHLT_LINK_INVALID
};
enum nhlt_device_type {
NHLT_DEVICE_BT = 0,
NHLT_DEVICE_DMIC = 1,
NHLT_DEVICE_I2S = 4,
NHLT_DEVICE_INVALID
};
struct nhlt_specific_cfg {
u32 size;
u8 caps[];
} __packed;
struct nhlt_fmt_cfg {
struct wav_fmt_ext fmt_ext;
struct nhlt_specific_cfg config;
} __packed;
struct nhlt_fmt {
u8 fmt_count;
struct nhlt_fmt_cfg fmt_config[];
} __packed;
struct nhlt_endpoint {
u32 length;
u8 linktype;
u8 instance_id;
u16 vendor_id;
u16 device_id;
u16 revision_id;
u32 subsystem_id;
u8 device_type;
u8 direction;
u8 virtual_bus_id;
struct nhlt_specific_cfg config;
} __packed;
struct nhlt_acpi_table {
struct acpi_table_header header;
u8 endpoint_count;
struct nhlt_endpoint desc[];
} __packed;
struct nhlt_resource_desc {
u32 extra;
u16 flags;
u64 addr_spc_gra;
u64 min_addr;
u64 max_addr;
u64 addr_trans_offset;
u64 length;
} __packed;
#define MIC_ARRAY_2CH 2
#define MIC_ARRAY_4CH 4
struct nhlt_device_specific_config {
u8 virtual_slot;
u8 config_type;
} __packed;
struct nhlt_dmic_array_config {
struct nhlt_device_specific_config device_config;
u8 array_type;
} __packed;
struct nhlt_vendor_dmic_array_config {
struct nhlt_dmic_array_config dmic_config;
u8 nb_mics;
/* TODO add vendor mic config */
} __packed;
enum {
NHLT_MIC_ARRAY_2CH_SMALL = 0xa,
NHLT_MIC_ARRAY_2CH_BIG = 0xb,
NHLT_MIC_ARRAY_4CH_1ST_GEOM = 0xc,
NHLT_MIC_ARRAY_4CH_L_SHAPED = 0xd,
NHLT_MIC_ARRAY_4CH_2ND_GEOM = 0xe,
NHLT_MIC_ARRAY_VENDOR_DEFINED = 0xf,
};
struct nhlt_acpi_table *intel_nhlt_init(struct device *dev);
void intel_nhlt_free(struct nhlt_acpi_table *addr);
int intel_nhlt_get_dmic_geo(struct device *dev, struct nhlt_acpi_table *nhlt);
#else
struct nhlt_acpi_table;
static inline struct nhlt_acpi_table *intel_nhlt_init(struct device *dev)
{
return NULL;
}
static inline void intel_nhlt_free(struct nhlt_acpi_table *addr)
{
}
static inline int intel_nhlt_get_dmic_geo(struct device *dev,
struct nhlt_acpi_table *nhlt)
{
return 0;
}
#endif
#endif