Claude
a882465573
After the configuration descriptor's first 9 bytes the event loop asked for min(wTotalLength, 128) whatever it was. A wTotalLength of 9 or less was then asked for again as "short" -- for ever, that slot never leaving enumeration (#170); 0 also issued a zero-length data stage. A set longer than the 128-byte buffer was cut without a word, its later interfaces never seen (#171). The decision is usb_config_request_length() (moved out of the event loop, then fixed): 9 or less is 0 -- "xhci: a configuration of N bytes has no interface -- not used", and nothing more is asked; longer than the buffer is cut and said -- "xhci: config of N bytes cut to 128 -- rest unseen" (at most 53 characters). The buffer stays 128 bytes; its size is #171's to rule. kernel/tests/test_usb_config.c, seen to fail first against the decision as it was (10 failures: wTotalLength 1 to 9 asked for again, the cut unsaid), now 20 checks, 0 failures. Both runs in logs/20261112-180140/kernel-tests/. Built for amd64, aarch64 and riscv64; the boots come with the protocol. #171's other box, a composite device on the SER5, is Captain Bob's. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_017RzZgrf7V7Zk2iczBXDRbm
41 lines
2.1 KiB
C
41 lines
2.1 KiB
C
/* SPDX-License-Identifier: LicenseRef-Starship-1.0
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* Copyright (c) 2023-2026 Robert A. James
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*/
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/* usb_config.h -- a USB configuration descriptor set, read: what xhci.c's event loop needs to know
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* of a device (its first interface, and that interface's endpoints). Moved out of the loop's
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* XHCI_XFER_CONFIG_DESC_FULL case unchanged, so it can be tested on the host
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* (kernel/tests/test_usb_config.c; docs/v4.0.0/plans/2026-11-12-kernel-host-tests.md).
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*/
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#ifndef STARKERNEL_USB_CONFIG_H
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#define STARKERNEL_USB_CONFIG_H
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#include <stdint.h>
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#define USB_CONFIG_NO_INTERFACE 0 /* no Interface descriptor in the set */
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#define USB_CONFIG_MSC 1 /* Mass Storage / SCSI / Bulk-Only Transport */
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#define USB_CONFIG_KBD 2 /* a HID boot keyboard */
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#define USB_CONFIG_OTHER 3 /* anything else -- not used */
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typedef struct {
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int kind; /* USB_CONFIG_* */
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uint8_t iface_class, iface_subclass, iface_protocol;
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uint8_t config_value; /* bConfigurationValue, for SET_CONFIGURATION */
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uint8_t bulk_in_ep, bulk_out_ep; /* USB_CONFIG_MSC: 0 when not found */
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uint16_t bulk_in_max, bulk_out_max;
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uint8_t hid_iface; /* USB_CONFIG_KBD */
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uint8_t hid_ep, hid_interval; /* hid_ep 0 when not found */
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uint16_t hid_max;
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} usb_config_t;
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/* Read the first `len` bytes of a configuration descriptor set (the Configuration descriptor and
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* the Interface and Endpoint descriptors after it). Only the first Interface descriptor counts;
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* a descriptor with bLength 0 ends the walk. Never reads past `len`. */
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void usb_config_parse(const uint8_t *desc, uint16_t len, usb_config_t *out);
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/* After the configuration descriptor's first 9 bytes: how many bytes of the whole set to ask
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* for, given its wTotalLength and the buffer's size `cap` -- 0 when wTotalLength is 9 or less (the
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* device is not used: #170); *cut set to 1 when the set is longer than the buffer (#171). */
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uint16_t usb_config_request_length(uint16_t total, uint16_t cap, int *cut);
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#endif
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