Commit 0fca1644 authored by Johann Fischer's avatar Johann Fischer Committed by Carles Cufi
Browse files

subsys: usb: rework usb string descriptor fixup 



This patch simplifies the handling of the string descriptors.
It introduces common macro for all string descriptors to
calculate the length of the bString.

Signed-off-by: default avatarJohann Fischer <j.fischer@phytec.de>
parent cf14a60f

subsys/usb/usb_descriptor.c

+48 −44
Original line number Diff line number Diff line
@@ -22,27 +22,20 @@ 
#include <logging/sys_log.h>



/*

 * 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.

 *

 * without null character:

 *   utf16_length = (sizeof(initializer_string) - 1) * 2

 * or:

 *   utf16_length = sizeof(initializer_string) * 2 - 2

 * the last index of the bString is:

 *   idx_max = sizeof(initializer_string) * 2 - 2 - 1

 * and the last index of the initializer_string without null character is:

 *   asci_idx_max = sizeof(initializer_string) - 1 - 1

 *

 *

 * The length of the string descriptor is calculated from the

 * size of the two octets bLength and bDescriptorType plus the

 * length of the UTF16LE string:

 *   descr_length = 2 + utf16_length

 *   descr_length = 2 + sizeof(initializer-string) * 2 - 2

 *   descr_length = sizeof(initializer-string) * 2

 *

 * The last index of the initializer_string without null character is:

 *   ascii_idx_max = bLength / 2 - 2

 * Use this macro to determine the last index of ASCII7 string.

 */

#define USB_BSTRING_ASCII_IDX_MAX(n)	(n / 2 - 2)



/*

 * The last index of the bString is:

 *   utf16le_idx_max = sizeof(initializer_string) * 2 - 2 - 1

 *   utf16le_idx_max = bLength - 2 - 1

 * Use this macro to determine the last index of UTF16LE string.

 */

#define USB_BSTRING_UTF16LE_IDX_MAX(n)	(n - 3)





/* Structure representing the global USB description */

struct dev_common_descriptor {
@@ -143,25 +136,28 @@ struct dev_common_descriptor { 
		struct usb_mfr_descriptor {

			u8_t bLength;

			u8_t bDescriptorType;

			u8_t bString[MFR_DESC_LENGTH - 2];

			u8_t bString[USB_BSTRING_LENGTH(

					CONFIG_USB_DEVICE_MANUFACTURER)];

		} __packed utf16le_mfr;



		struct usb_product_descriptor {

			u8_t bLength;

			u8_t bDescriptorType;

			u8_t bString[PRODUCT_DESC_LENGTH - 2];

			u8_t bString[USB_BSTRING_LENGTH(

					CONFIG_USB_DEVICE_PRODUCT)];

		} __packed utf16le_product;



		struct usb_sn_descriptor {

			u8_t bLength;

			u8_t bDescriptorType;

			u8_t bString[SN_DESC_LENGTH - 2];

			u8_t bString[USB_BSTRING_LENGTH(CONFIG_USB_DEVICE_SN)];

		} __packed utf16le_sn;

#ifdef CONFIG_USB_DEVICE_NETWORK_ECM

		struct usb_cdc_ecm_mac_descriptor {

			u8_t bLength;

			u8_t bDescriptorType;

			u8_t bString[ECM_MAC_DESC_LENGTH - 2];

			u8_t bString[USB_BSTRING_LENGTH(

					CONFIG_USB_DEVICE_NETWORK_ECM_MAC)];

		} __packed utf16le_mac;

#endif /* CONFIG_USB_DEVICE_NETWORK_ECM */

	} __packed string_descr;
@@ -768,25 +764,29 @@ static struct dev_common_descriptor common_desc = { 
		},

		/* Manufacturer String Descriptor */

		.utf16le_mfr = {

			.bLength = MFR_DESC_LENGTH,

			.bLength = USB_STRING_DESCRIPTOR_LENGTH(

					CONFIG_USB_DEVICE_MANUFACTURER),

			.bDescriptorType = USB_STRING_DESC,

			.bString = CONFIG_USB_DEVICE_MANUFACTURER,

		},

		/* Product String Descriptor */

		.utf16le_product = {

			.bLength = PRODUCT_DESC_LENGTH,

			.bLength = USB_STRING_DESCRIPTOR_LENGTH(

					CONFIG_USB_DEVICE_PRODUCT),

			.bDescriptorType = USB_STRING_DESC,

			.bString = CONFIG_USB_DEVICE_PRODUCT,

		},

		/* Serial Number String Descriptor */

		.utf16le_sn = {

			.bLength = SN_DESC_LENGTH,

			.bLength = USB_STRING_DESCRIPTOR_LENGTH(

					CONFIG_USB_DEVICE_SN),

			.bDescriptorType = USB_STRING_DESC,

			.bString = CONFIG_USB_DEVICE_SN,

		},

#ifdef CONFIG_USB_DEVICE_NETWORK_ECM

		.utf16le_mac = {

			.bLength = ECM_MAC_DESC_LENGTH,

			.bLength = USB_STRING_DESCRIPTOR_LENGTH(

					CONFIG_USB_DEVICE_NETWORK_ECM_MAC),

			.bDescriptorType = USB_STRING_DESC,

			.bString = CONFIG_USB_DEVICE_NETWORK_ECM_MAC

		},
@@ -800,38 +800,42 @@ static struct dev_common_descriptor common_desc = { 




/*

 * Utility function: Inline conversion an ASCII-7 string of length asci_idx_max

 * into a UTF16-LE string of idx_max bytes.

 * This function fixes bString by transforming the ASCII-7 string

 * into a UTF16-LE during runtime.

 */

void ascii7_to_utf16le(int idx_max, int asci_idx_max, u8_t *buf)

static void ascii7_to_utf16le(void *descriptor)

{

	struct usb_string_descriptor *str_descr = descriptor;

	int idx_max = USB_BSTRING_UTF16LE_IDX_MAX(str_descr->bLength);

	int ascii_idx_max = USB_BSTRING_ASCII_IDX_MAX(str_descr->bLength);

	u8_t *buf = (u8_t *)&str_descr->bString;



	SYS_LOG_DBG("idx_max %d, ascii_idx_max %d, buf %x",

		    idx_max, ascii_idx_max, (u32_t)buf);



	for (int i = idx_max; i >= 0; i -= 2) {

		SYS_LOG_DBG("char %c : %x, idx %d -> %d",

			    buf[asci_idx_max],

			    buf[asci_idx_max],

			    asci_idx_max, i);

		__ASSERT(buf[asci_idx_max] > 0x1F && buf[asci_idx_max] < 0x7F,

			    buf[ascii_idx_max],

			    buf[ascii_idx_max],

			    ascii_idx_max, i);

		__ASSERT(buf[ascii_idx_max] > 0x1F && buf[ascii_idx_max] < 0x7F,

			 "Only printable ascii-7 characters are allowed in USB "

			 "string descriptors");

		buf[i] = 0;

		buf[i - 1] = buf[asci_idx_max--];

		buf[i - 1] = buf[ascii_idx_max--];

	}

}



u8_t *usb_get_device_descriptor(void)

{

	ascii7_to_utf16le(MFR_UC_IDX_MAX, MFR_STRING_IDX_MAX,

		(u8_t *)common_desc.string_descr.utf16le_mfr.bString);

	ascii7_to_utf16le(&common_desc.string_descr.utf16le_mfr);



	ascii7_to_utf16le(PRODUCT_UC_IDX_MAX, PRODUCT_STRING_IDX_MAX,

		(u8_t *)common_desc.string_descr.utf16le_product.bString);

	ascii7_to_utf16le(&common_desc.string_descr.utf16le_product);



	ascii7_to_utf16le(SN_UC_IDX_MAX, SN_STRING_IDX_MAX,

		(u8_t *)common_desc.string_descr.utf16le_sn.bString);

	ascii7_to_utf16le(&common_desc.string_descr.utf16le_sn);



#ifdef CONFIG_USB_DEVICE_NETWORK_ECM

	ascii7_to_utf16le(ECM_MAC_UC_IDX_MAX, ECM_STRING_IDX_MAX,

		(u8_t *)common_desc.string_descr.utf16le_mac.bString);

	ascii7_to_utf16le(&common_desc.string_descr.utf16le_mac);

#endif



	return (u8_t *) &common_desc;

subsys/usb/usb_descriptor.h

+22 −15
Original line number Diff line number Diff line
@@ -96,23 +96,30 @@ 
#define FIRST_IFACE_DFU			(FIRST_IFACE_BLUETOOTH + \

					 NUMOF_IFACES_BLUETOOTH)



#define MFR_DESC_LENGTH		(sizeof(CONFIG_USB_DEVICE_MANUFACTURER) * 2)

#define MFR_UC_IDX_MAX		(MFR_DESC_LENGTH - 3)

#define MFR_STRING_IDX_MAX	(sizeof(CONFIG_USB_DEVICE_MANUFACTURER) - 2)



#define PRODUCT_DESC_LENGTH	(sizeof(CONFIG_USB_DEVICE_PRODUCT) * 2)

#define PRODUCT_UC_IDX_MAX	(PRODUCT_DESC_LENGTH - 3)

#define PRODUCT_STRING_IDX_MAX	(sizeof(CONFIG_USB_DEVICE_PRODUCT) - 2)



#define SN_DESC_LENGTH		(sizeof(CONFIG_USB_DEVICE_SN) * 2)

#define SN_UC_IDX_MAX		(SN_DESC_LENGTH - 3)

#define SN_STRING_IDX_MAX	(sizeof(CONFIG_USB_DEVICE_SN) - 2)

/*

 * 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)



#define ECM_MAC_DESC_LENGTH	(sizeof(CONFIG_USB_DEVICE_NETWORK_ECM_MAC) * 2)

#define ECM_MAC_UC_IDX_MAX	(ECM_MAC_DESC_LENGTH - 3)

#define ECM_STRING_IDX_MAX	(sizeof(CONFIG_USB_DEVICE_NETWORK_ECM_MAC) - 2)

/*

 * The length of the string descriptor (bLength) is calculated from the

 * size of the two octets bLength and bDescriptorType plus the

 * length of the UTF16LE string:

 *

 *   bLength = 2 + bString_length

 *   bLength = 2 + sizeof(initializer_string) * 2 - 2

 *   bLength = sizeof(initializer_string) * 2

 * Use this macro to determine the bLength of the string descriptor.

 */

#define USB_STRING_DESCRIPTOR_LENGTH(s)	(sizeof(s) * 2)



void ascii7_to_utf16le(int idx_max, int asci_idx_max, u8_t *buf);

u8_t *usb_get_device_descriptor(void);



#ifdef CONFIG_USB_DEVICE_HID

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