From cf9610f9116d55c5a66ef9f1faecacabd93a9322 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Mon, 24 Aug 2026 08:46:03 -0700 Subject: Merge tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl Pull pin control updates from Linus Walleij: "Core changes: - Use the non-blocking mux_state_try_select() in the generic MUX pin control back-end - Free pin maps on pinctrl_generic_to_map() failure in the core helpers New hardware pin control: - Qualcomm Maili TLMM SoC, PMG1110 PMIC, and Eliza LPASS LPI TLMM SoC (this is for the low power audio, LPASS = Low Power Audio SubSystem portions) - Upboard support on top of the Intel pin controller - Apple T6030 and T6031 support (just compatible strings) - Samsung Exynos 8855 SoC - Mediatek MT6858 SoC - Rockchip RK3308B and RV1106 SoCs - Airoha EN7523 and AN7563 SoCs Improvements: - Qualcomm TLMM GPIOs are unconditionally marked as wakeup capable - Qualcomm improvements on top of the Qualcomm PDC (power domain controller) irqchip improvements from tglx:s tree - Qualcomm IPQ806x and IPQ9650 non-urgent pin grop fixups - The NPCM8xx driver has been put into shape fixing many pin and group definitions - Some non-urgent Tegra 264 pin assignments are fixed up - Some non-urgent fixups to Airoha AN7581 and AN7583 registers and pin assignments, missing features etc" * tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (130 commits) dt-bindings: pinctrl: Convert TI DA850 pupd to DT schema pinctrl: meson: sync some modify from A4 pinctrl: meson: a4: Add input enable pin configuration pinctrl: realtek: rtd1625: remove unused group name spdif_sel pinctrl: realtek: rtd1625: fix base_bit for VE4 GPIO 13 dt-bindings: pinctrl: microchip,pic32mzda-pinctrl: Convert to DT schema Revert "Merge branch 'ib-rsk7204' into devel" pinctrl: rockchip: Add RV1106 pinctrl support dt-bindings: pinctrl: rockchip: Add RV1106 compatible pinctrl: rockchip: Decode drive strength in the get function pinctrl: fix PINCTRL_GENERIC_MUX not always being selectable pinctrl: airoha: add support of an7563 SoC dt-bindings: pinctrl: airoha: add support of an7563 pin controller pinctrl: airoha: try to find chip scu node by phandle first pinctrl: airoha: add support of en7523 SoC dt-bindings: pinctrl: airoha: add support of en7523 pin controller pinctrl: airoha: an7583: add support for olt pinmux pinctrl: airoha: an7583: add support for pon_alt pinmux pinctrl: airoha: an7583: add support for npu_uart pinmux dt-bindings: pinctrl: airoha: an7583: add missed features ... --- Documentation/driver-api/usb/bulk-streams.rst | 83 +++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) create mode 100644 Documentation/driver-api/usb/bulk-streams.rst (limited to 'Documentation/driver-api/usb/bulk-streams.rst') diff --git a/Documentation/driver-api/usb/bulk-streams.rst b/Documentation/driver-api/usb/bulk-streams.rst new file mode 100644 index 000000000..eeefe582f --- /dev/null +++ b/Documentation/driver-api/usb/bulk-streams.rst @@ -0,0 +1,83 @@ +USB bulk streams +~~~~~~~~~~~~~~~~ + +Background +========== + +Bulk endpoint streams were added in the USB 3.0 specification. Streams allow a +device driver to overload a bulk endpoint so that multiple transfers can be +queued at once. + +Streams are defined in sections 4.4.6.4 and 8.12.1.4 of the Universal Serial Bus +3.0 specification at https://www.usb.org/developers/docs/ The USB Attached SCSI +Protocol, which uses streams to queue multiple SCSI commands, can be found on +the T10 website (https://t10.org/). + + +Device-side implications +======================== + +Once a buffer has been queued to a stream ring, the device is notified (through +an out-of-band mechanism on another endpoint) that data is ready for that stream +ID. The device then tells the host which "stream" it wants to start. The host +can also initiate a transfer on a stream without the device asking, but the +device can refuse that transfer. Devices can switch between streams at any +time. + + +Driver implications +=================== + +:: + + int usb_alloc_streams(struct usb_interface *interface, + struct usb_host_endpoint **eps, unsigned int num_eps, + unsigned int num_streams, gfp_t mem_flags); + +Device drivers will call this API to request that the host controller driver +allocate memory so the driver can use up to num_streams stream IDs. They must +pass an array of usb_host_endpoints that need to be setup with similar stream +IDs. This is to ensure that a UASP driver will be able to use the same stream +ID for the bulk IN and OUT endpoints used in a Bi-directional command sequence. + +The return value is an error condition (if one of the endpoints doesn't support +streams, or the xHCI driver ran out of memory), or the number of streams the +host controller allocated for this endpoint. The xHCI host controller hardware +declares how many stream IDs it can support, and each bulk endpoint on a +SuperSpeed device will say how many stream IDs it can handle. Therefore, +drivers should be able to deal with being allocated less stream IDs than they +requested. + +Do NOT call this function if you have URBs enqueued for any of the endpoints +passed in as arguments. Do not call this function to request less than two +streams. + +Drivers will only be allowed to call this API once for the same endpoint +without calling usb_free_streams(). This is a simplification for the xHCI host +controller driver, and may change in the future. + + +Picking new Stream IDs to use +============================= + +Stream ID 0 is reserved, and should not be used to communicate with devices. If +usb_alloc_streams() returns with a value of N, you may use streams 1 though N. +To queue an URB for a specific stream, set the urb->stream_id value. If the +endpoint does not support streams, an error will be returned. + +Note that new API to choose the next stream ID will have to be added if the xHCI +driver supports secondary stream IDs. + + +Clean up +======== + +If a driver wishes to stop using streams to communicate with the device, it +should call:: + + void usb_free_streams(struct usb_interface *interface, + struct usb_host_endpoint **eps, unsigned int num_eps, + gfp_t mem_flags); + +All stream IDs will be deallocated when the driver releases the interface, to +ensure that drivers that don't support streams will be able to use the endpoint. -- cgit v1.3.1