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usb: device_next: add the missing const qualifier and save some RAM

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In the USBD_DESC_STRING_DEFINE macro defenition the const qualifier is
missing. Also, do not reserve room for the UTF16LE conversion, as this
is done on the fly in the stack.

Signed-off-by: Johann Fischer <johann.fischer@nordicsemi.no>
This commit is contained in:
Johann Fischer 2025-06-12 18:59:44 +02:00 • committed by Benjamin Cabé
commit 0e127e6b10
1 changed files with 2 additions and 14 deletions
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16
include/zephyr/usb/usbd.h
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@ -43,18 +43,6 @@ extern "C" {
/* Maximum bulk max packet size the stack supports */
#define USBD_MAX_BULK_MPS COND_CODE_1(USBD_SUPPORTS_HIGH_SPEED, (512), (64))
/*
* The USB Unicode bString is encoded in UTF16LE, which means it takes up
* twice the amount of bytes than the same string encoded in ASCII7.
* Use this macro to determine the length of the bString array.
*
* bString length without null character:
* bString_length = (sizeof(initializer_string) - 1) * 2
* or:
* bString_length = sizeof(initializer_string) * 2 - 2
*/
#define USB_BSTRING_LENGTH(s) (sizeof(s) * 2 - 2)
/*
* The length of the string descriptor (bLength) is calculated from the
* size of the two octets bLength and bDescriptorType plus the
@ -574,7 +562,7 @@ static inline void *usbd_class_get_private(const struct usbd_class_data *const c
* @param name Language string descriptor node identifier.
*/
#define USBD_DESC_LANG_DEFINE(name) \
static uint16_t langid_##name = sys_cpu_to_le16(0x0409); \
static const uint16_t langid_##name = sys_cpu_to_le16(0x0409); \
static struct usbd_desc_node name = { \
.str = { \
.idx = 0, \
@ -597,7 +585,7 @@ static inline void *usbd_class_get_private(const struct usbd_class_data *const c
* @param d_utype String descriptor usage type
*/
#define USBD_DESC_STRING_DEFINE(d_name, d_string, d_utype) \
static uint8_t ascii_##d_name[USB_BSTRING_LENGTH(d_string)] = d_string; \
static const uint8_t ascii_##d_name[sizeof(d_string)] = d_string; \
static struct usbd_desc_node d_name = { \
.str = { \
.utype = d_utype, \