kernel/git/stable/linux-stable.git/drivers/usb/host/xhci-mem.c, branch master

usb: xhci: Fix HCS_ERST_MAX conversion

2026-08-31T09:43:00+00:00

This fixes one broken line in commit 6d45e9556d4a ("usb: xhci: standardize multi bit-field macros") included in 7.3-rc1 kernel HCS_ERST_MAX holds power of 2 value for maximum number of segments. In the culprit commit, this was incorrectly converted to "shift up 2". On hardware where this field is zero, this results in xhci_alloc_erst() calling dma_alloc_coherent() with size = 0, leading to a horrible splat and non-usable XHCI. Revert the shift-up-2 to the BIT() macro. Fixes: 6d45e9556d4a ("usb: xhci: standardize multi bit-field macros") Cc: Niklas Neronin Signed-off-by: Chen-Yu Tsai Signed-off-by: Mathias Nyman Tested-by: Pierre-David Belanger Link: https://patch.msgid.link/20260831090448.95644-2-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman

usb: xhci: replace Unicode quotes with ASCII apostrophes

2026-08-14T01:26:41+00:00

Non-ASCII characters trigger git send-email to prompt for encoding on each modification near them, which is unnecessary and annoying. Using plain ASCII avoids these prompts and does not change its meaning. This change only affects comments and has no functional impact. Signed-off-by: Niklas Neronin Signed-off-by: Mathias Nyman Link: https://patch.msgid.link/20260806142113.2436238-16-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman

usb: xhci: remove redundant 'xhci' pointer from endpoint struct

2026-08-14T01:26:41+00:00

The 'xhci_virt_ep' struct currently contains a pointer to its parent 'xhci_hcd' struct. Since all endpoint-related structs are contained within 'xhci_hcd', this pointer is redundant. Remove the 'xhci' pointer from 'xhci_virt_ep' and instead pass it explicitly to functions that require it, as some already do it. This change reduces unnecessary complexity and aligns the code with the rest of the xhci driver. Memory impact: For each device connected a struct 'xhci_virt_device' is allocated, this struct conatains a 31 slot array of struct 'xhci_virt_ep'. A USB hub consumes 1 slot, but every downstream device consumes another slot. This means that the total memory saved buy this patch is: Devices * 31 * 8 bytes Signed-off-by: Niklas Neronin Signed-off-by: Mathias Nyman Link: https://patch.msgid.link/20260806142113.2436238-15-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman

usb: xhci: standardize multi bit-field macros

2026-08-14T01:26:41+00:00

This patch aims to unify the format of register macros and masks within the xHCI driver. Currently, register macros have inconsistent bit-field masks, get macros, and set macros, with varying naming conventions and functionalities. ==================== Proposal ==================== * Introduce a standardized approach by using only mask macros for each bit field, leveraging GENMASK() for enhanced clarity. #define HCC_MAX_PSA GENMASK(15, 12) * Utilize FIELD_GET() and FIELD_PREP() macros directly in the C code for getting and setting values, ensuring consistency and readability. u32 psa = FIELD_GET(HCC_MAX_PSA, reg); * Maintain exceptions for macros that perform custom operations. #define CTX_SIZE(_hcc) (_hcc & HCC_64BYTE_CONTEXT ? 64 : 32) * Note, while FIELD_*() macros are beneficial, I am not suggesting that they should always be used. Instead, use them where they simplify the code and eliminate the necessity for custom get/set macros. In the example below, additional FIELD_PREP() or FIELD_MODIFY() is not beneficial. #define HCS_MAX_SCRATCHPAD(p) (FIELD_GET(HCS_MAX_SP_HI, (p)) << 5 | \ FIELD_GET(HCS_MAX_SP_LO, (p))) ==================== Improvements ==================== Simplified Macros: By reducing custom macros, the code becomes more straightforward. Macros FIELD_GET() and FIELD_PREP() are commonly used, which contributes to the code readability and consistency. $ git grep -n 'FIELD_GET' | wc -l 9027 $ git grep -n 'FIELD_PREP' | wc -l 15407 Consistent Return Type: All bit macros will return unsigned 64-bit values, mitigating potential cross-architecture issues. Unified Bit Range Definition: The mask macro will define bit ranges, eliminating separate definitions for get/set macros. Because, FIELD_GET() & FIELD_PREP() use mask macro. Cleaner header file with less macros: Fewer macros result in a cleaner and more manageable header file. Signed-off-by: Niklas Neronin Signed-off-by: Mathias Nyman Link: https://patch.msgid.link/20260806142113.2436238-12-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman

xhci: fix frame id calculation and checks for isoc URBs

2026-08-14T01:26:40+00:00

Check if the expected frame IDs for a isochronous URB submitted mid stream is within the valid frame time window that xHC controller is capable of queuing TDs. The range only needs to be checked once per URB as the isoc TDs of an URB are queued in one go with spinlock held and interrupts disabled. Calculate the valid frame window start and end frame id in frames instead of microframes to better match how xhci specification section 4.11.2.5 does it. Don't add frame id gaps or change scheduling to SIA mid stream if the start frame is outside the valid frame winow. Only print a debug message. Some devices can't handle gaps in isochronous transfers. Calculate a valid start frame for the first URB of a stream, and align it to a full frame, or to interval start if interval is longer than a frame Set urb->start_frame value for every URB cc: Dylan Robinson Signed-off-by: Mathias Nyman Link: https://patch.msgid.link/20260806142113.2436238-2-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman

usb: xhci: allocate internal DCBAA mirror dynamically

2026-06-03T17:23:30+00:00

Allocate the internal virtual device array dynamically based on the maximum number of slots reported by the host controller. Previously, the array was always allocated to the absolute maximum of 255 entries. Repurpose the 'MAX_HC_SLOTS' macro to limit the number of enabled slots. This mirrors how the maximum number of ports and interrupters are handled. The allocation now uses kcalloc_node(), which zeroes the memory automatically, making the explicit memset() call unnecessary. Signed-off-by: Niklas Neronin Signed-off-by: Mathias Nyman Link: https://patch.msgid.link/20260603091132.1110849-16-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman

usb: xhci: allocate DCBAA based on host controller max slots

2026-06-03T17:23:30+00:00

Allocate the Device Context Base Address Array (DCBAA) according to the maximum number of device slots supported by the host controller, instead of always allocating the absolute maximum of 255 entries. The xHCI specification defines the DCBAA size as (MaxSlotsEnabled + 1) entries. In the xhci driver there is currently no distinction between MaxSlots and MaxSlotsEnabled, as all available slots are enabled during initialization. As a result, 'max_slots' effectively represents both values. This change allows the xHCI driver to respect custom slot limits, reduces unnecessary memory usage, and removes the obsolete "TODO" comment. Signed-off-by: Niklas Neronin Signed-off-by: Mathias Nyman Link: https://patch.msgid.link/20260603091132.1110849-15-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman

usb: xhci: refactor DCBAA struct

2026-06-03T17:23:29+00:00

Embed the 'xhci_device_context_array' structure directly within 'xhci_hcd' instead of allocating it as a separate block. Only the array of device context addresses is now allocated separately. Since the device context addresses are no longer part of an array structure, rename 'dev_context_ptrs' to 'ctx_array' for clearer access semantics. Also remove the redundant comment next to the 'ctx_array' allocation; using dma_alloc_coherent() for 64-bit * N allocations guarantees both physically contiguous and properly aligned for 64-byte boundaries. The xHCI section (5.4.6) refers to DCBAAP instead of DCBAA (6.1). This change does not modify the number of host controller slots but simplifies memory management and prepares the driver for a variable number of HC slots in the future. Signed-off-by: Niklas Neronin Signed-off-by: Mathias Nyman Link: https://patch.msgid.link/20260603091132.1110849-14-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman

usb: xhci: remove legacy 'num_trbs_free' tracking

2026-06-03T17:23:28+00:00

Keeping track of free TRBs in a ring by adding and subtracting each time a enqueue or dequeue pointer is modified has proven to be buggy and complicated, especially over long periods of time. The xhci driver has already moved to calculating free TRBs dynamically based on ring size and the enqueue/dequeue positions. The DbC path is the last user of 'num_trbs_free'. Rather than maintaining two separate accounting mechanisms, remove the field entirely and switch DbC to use xhci_num_trbs_free(). Since 'num_trbs_free' undercounts by one, and xhci_num_trbs_free() does not, the check for sufficient free TRBs is adjusted. Signed-off-by: Niklas Neronin Signed-off-by: Mathias Nyman Link: https://patch.msgid.link/20260603091132.1110849-3-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman

usb: xhci: remove duplicate '0x' prefix

2026-04-02T13:55:38+00:00

Prefix "0x" is automatically added by '%pad'. Signed-off-by: Niklas Neronin Signed-off-by: Mathias Nyman Link: https://patch.msgid.link/20260402131342.2628648-25-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman