@@ -104,6 +104,15 @@ config USB_XHCI_RZV2M
Say 'Y' to enable the support for the xHCI host controller
found in Renesas RZ/V2M SoC.
+config USB_XHCI_SIDEBAND
+ tristate "xHCI support for sideband"
+ help
+ Say 'Y' to enable the support for the xHCI sideband capability.
+ provide a mechanism for a sideband datapath for payload associated
+ with audio class endpoints. This allows for an audio DSP to use
+ xHCI USB endpoints directly, allowing CPU to sleep while playing
+ audio
+
config USB_XHCI_TEGRA
tristate "xHCI support for NVIDIA Tegra SoCs"
depends on PHY_TEGRA_XUSB
@@ -32,6 +32,8 @@ endif
xhci-rcar-hcd-y += xhci-rcar.o
xhci-rcar-hcd-$(CONFIG_USB_XHCI_RZV2M) += xhci-rzv2m.o
+obj-$(CONFIG_USB_XHCI_SIDEBAND) += xhci-sideband.o
+
obj-$(CONFIG_USB_PCI) += pci-quirks.o
obj-$(CONFIG_USB_EHCI_HCD) += ehci-hcd.o
new file mode 100644
@@ -0,0 +1,411 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * xHCI host controller sideband support
+ *
+ * Copyright (c) 2023, Intel Corporation.
+ *
+ * Author: Mathias Nyman
+ */
+
+#include <linux/usb/xhci-sideband.h>
+#include <linux/dma-direct.h>
+
+#include "xhci.h"
+
+/* sideband internal helpers */
+static struct sg_table *
+xhci_ring_to_sgtable(struct xhci_sideband *sb, struct xhci_ring *ring)
+{
+ struct xhci_segment *seg;
+ struct sg_table *sgt;
+ unsigned int n_pages;
+ struct page **pages;
+ struct device *dev;
+ size_t sz;
+ int i;
+
+ dev = xhci_to_hcd(sb->xhci)->self.sysdev;
+ sz = ring->num_segs * TRB_SEGMENT_SIZE;
+ n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
+ pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
+ if (!pages)
+ return NULL;
+
+ sgt = kzalloc(sizeof(struct sg_table), GFP_KERNEL);
+ if (!sgt) {
+ kvfree(pages);
+ return NULL;
+ }
+
+ seg = ring->first_seg;
+ /*
+ * Rings can potentially have multiple segments, create an array that
+ * carries page references to allocated segments. Utilize the
+ * sg_alloc_table_from_pages() to create the sg table, and to ensure
+ * that page links are created.
+ */
+ for (i = 0; i < ring->num_segs; i++) {
+ dma_get_sgtable(dev, sgt, seg->trbs, seg->dma,
+ TRB_SEGMENT_SIZE);
+ pages[i] = sg_page(sgt->sgl);
+ sg_free_table(sgt);
+ seg = seg->next;
+ }
+
+ if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
+ kvfree(pages);
+ kfree(sgt);
+
+ return NULL;
+ }
+ /*
+ * Save first segment dma address to sg dma_address field for the sideband
+ * client to have access to the IOVA of the ring.
+ */
+ sg_dma_address(sgt->sgl) = ring->first_seg->dma;
+
+ return sgt;
+}
+
+static void
+__xhci_sideband_remove_endpoint(struct xhci_sideband *sb, struct xhci_virt_ep *ep)
+{
+ /*
+ * Issue a stop endpoint command when an endpoint is removed.
+ * The stop ep cmd handler will handle the ring cleanup.
+ */
+ xhci_stop_endpoint_sync(sb->xhci, ep, 0, GFP_KERNEL);
+
+ ep->sideband = NULL;
+ sb->eps[ep->ep_index] = NULL;
+}
+
+/* sideband api functions */
+
+/**
+ * xhci_sideband_add_endpoint - add endpoint to sideband access list
+ * @sb: sideband instance for this usb device
+ * @host_ep: usb host endpoint
+ *
+ * Adds an endpoint to the list of sideband accessed endpoints for this usb
+ * device.
+ * After an endpoint is added the sideband client can get the endpoint transfer
+ * ring buffer by calling xhci_sideband_endpoint_buffer()
+ *
+ * Return: 0 on success, negative error otherwise.
+ */
+int
+xhci_sideband_add_endpoint(struct xhci_sideband *sb,
+ struct usb_host_endpoint *host_ep)
+{
+ struct xhci_virt_ep *ep;
+ unsigned int ep_index;
+
+ mutex_lock(&sb->mutex);
+ ep_index = xhci_get_endpoint_index(&host_ep->desc);
+ ep = &sb->vdev->eps[ep_index];
+
+ if (ep->ep_state & EP_HAS_STREAMS) {
+ mutex_unlock(&sb->mutex);
+ return -EINVAL;
+ }
+
+ /*
+ * Note, we don't know the DMA mask of the audio DSP device, if its
+ * smaller than for xhci it won't be able to access the endpoint ring
+ * buffer. This could be solved by not allowing the audio class driver
+ * to add the endpoint the normal way, but instead offload it immediately,
+ * and let this function add the endpoint and allocate the ring buffer
+ * with the smallest common DMA mask
+ */
+ if (sb->eps[ep_index] || ep->sideband) {
+ mutex_unlock(&sb->mutex);
+ return -EBUSY;
+ }
+
+ ep->sideband = sb;
+ sb->eps[ep_index] = ep;
+ mutex_unlock(&sb->mutex);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(xhci_sideband_add_endpoint);
+
+/**
+ * xhci_sideband_remove_endpoint - remove endpoint from sideband access list
+ * @sb: sideband instance for this usb device
+ * @host_ep: usb host endpoint
+ *
+ * Removes an endpoint from the list of sideband accessed endpoints for this usb
+ * device.
+ * sideband client should no longer touch the endpoint transfer buffer after
+ * calling this.
+ *
+ * Return: 0 on success, negative error otherwise.
+ */
+int
+xhci_sideband_remove_endpoint(struct xhci_sideband *sb,
+ struct usb_host_endpoint *host_ep)
+{
+ struct xhci_virt_ep *ep;
+ unsigned int ep_index;
+
+ mutex_lock(&sb->mutex);
+ ep_index = xhci_get_endpoint_index(&host_ep->desc);
+ ep = sb->eps[ep_index];
+
+ if (!ep || !ep->sideband) {
+ mutex_unlock(&sb->mutex);
+ return -ENODEV;
+ }
+
+ __xhci_sideband_remove_endpoint(sb, ep);
+ xhci_initialize_ring_info(ep->ring, 1);
+ mutex_unlock(&sb->mutex);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(xhci_sideband_remove_endpoint);
+
+int
+xhci_sideband_stop_endpoint(struct xhci_sideband *sb,
+ struct usb_host_endpoint *host_ep)
+{
+ struct xhci_virt_ep *ep;
+ unsigned int ep_index;
+
+ ep_index = xhci_get_endpoint_index(&host_ep->desc);
+ ep = sb->eps[ep_index];
+
+ if (!ep || ep->sideband != sb)
+ return -EINVAL;
+
+ return xhci_stop_endpoint_sync(sb->xhci, ep, 0, GFP_KERNEL);
+}
+EXPORT_SYMBOL_GPL(xhci_sideband_stop_endpoint);
+
+/**
+ * xhci_sideband_get_endpoint_buffer - gets the endpoint transfer buffer address
+ * @sb: sideband instance for this usb device
+ * @host_ep: usb host endpoint
+ *
+ * Returns the address of the endpoint buffer where xHC controller reads queued
+ * transfer TRBs from. This is the starting address of the ringbuffer where the
+ * sideband client should write TRBs to.
+ *
+ * Caller needs to free the returned sg_table
+ *
+ * Return: struct sg_table * if successful. NULL otherwise.
+ */
+struct sg_table *
+xhci_sideband_get_endpoint_buffer(struct xhci_sideband *sb,
+ struct usb_host_endpoint *host_ep)
+{
+ struct xhci_virt_ep *ep;
+ unsigned int ep_index;
+
+ ep_index = xhci_get_endpoint_index(&host_ep->desc);
+ ep = sb->eps[ep_index];
+
+ if (!ep)
+ return NULL;
+
+ return xhci_ring_to_sgtable(sb, ep->ring);
+}
+EXPORT_SYMBOL_GPL(xhci_sideband_get_endpoint_buffer);
+
+/**
+ * xhci_sideband_get_event_buffer - return the event buffer for this device
+ * @sb: sideband instance for this usb device
+ *
+ * If a secondary xhci interupter is set up for this usb device then this
+ * function returns the address of the event buffer where xHC writes
+ * the transfer completion events.
+ *
+ * Caller needs to free the returned sg_table
+ *
+ * Return: struct sg_table * if successful. NULL otherwise.
+ */
+struct sg_table *
+xhci_sideband_get_event_buffer(struct xhci_sideband *sb)
+{
+ if (!sb || !sb->ir)
+ return NULL;
+
+ return xhci_ring_to_sgtable(sb, sb->ir->event_ring);
+}
+EXPORT_SYMBOL_GPL(xhci_sideband_get_event_buffer);
+
+/**
+ * xhci_sideband_create_interrupter - creates a new interrupter for this sideband
+ * @sb: sideband instance for this usb device
+ * @num_seg: number of event ring segments to allocate
+ * @ip_autoclear: IP autoclearing support such as MSI implemented
+ *
+ * Sets up a xhci interrupter that can be used for this sideband accessed usb
+ * device. Transfer events for this device can be routed to this interrupters
+ * event ring by setting the 'Interrupter Target' field correctly when queueing
+ * the transfer TRBs.
+ * Once this interrupter is created the interrupter target ID can be obtained
+ * by calling xhci_sideband_interrupter_id()
+ *
+ * Returns 0 on success, negative error otherwise
+ */
+int
+xhci_sideband_create_interrupter(struct xhci_sideband *sb, int num_seg,
+ bool ip_autoclear)
+{
+ int ret = 0;
+
+ if (!sb)
+ return -ENODEV;
+
+ mutex_lock(&sb->mutex);
+ if (sb->ir) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ sb->ir = xhci_create_secondary_interrupter(xhci_to_hcd(sb->xhci),
+ num_seg);
+ if (!sb->ir) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ sb->ir->ip_autoclear = ip_autoclear;
+
+out:
+ mutex_unlock(&sb->mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(xhci_sideband_create_interrupter);
+
+/**
+ * xhci_sideband_remove_interrupter - remove the interrupter from a sideband
+ * @sb: sideband instance for this usb device
+ *
+ * Removes a registered interrupt for a sideband. This would allow for other
+ * sideband users to utilize this interrupter.
+ */
+void
+xhci_sideband_remove_interrupter(struct xhci_sideband *sb)
+{
+ if (!sb || !sb->ir)
+ return;
+
+ mutex_lock(&sb->mutex);
+ xhci_remove_secondary_interrupter(xhci_to_hcd(sb->xhci), sb->ir);
+
+ sb->ir = NULL;
+ mutex_unlock(&sb->mutex);
+}
+EXPORT_SYMBOL_GPL(xhci_sideband_remove_interrupter);
+
+/**
+ * xhci_sideband_interrupter_id - return the interrupter target id
+ * @sb: sideband instance for this usb device
+ *
+ * If a secondary xhci interrupter is set up for this usb device then this
+ * function returns the ID used by the interrupter. The sideband client
+ * needs to write this ID to the 'Interrupter Target' field of the transfer TRBs
+ * it queues on the endpoints transfer ring to ensure transfer completion event
+ * are written by xHC to the correct interrupter event ring.
+ *
+ * Returns interrupter id on success, negative error othgerwise
+ */
+int
+xhci_sideband_interrupter_id(struct xhci_sideband *sb)
+{
+ if (!sb || !sb->ir)
+ return -ENODEV;
+
+ return sb->ir->intr_num;
+}
+EXPORT_SYMBOL_GPL(xhci_sideband_interrupter_id);
+
+/**
+ * xhci_sideband_register - register a sideband for a usb device
+ * @udev: usb device to be accessed via sideband
+ *
+ * Allows for clients to utilize XHCI interrupters and fetch transfer and event
+ * ring parameters for executing data transfers.
+ *
+ * Return: pointer to a new xhci_sideband instance if successful. NULL otherwise.
+ */
+struct xhci_sideband *
+xhci_sideband_register(struct usb_device *udev)
+{
+ struct usb_hcd *hcd = bus_to_hcd(udev->bus);
+ struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+ struct xhci_virt_device *vdev;
+ struct xhci_sideband *sb;
+
+ /* make sure the usb device is connected to a xhci controller */
+ if (!udev->slot_id)
+ return NULL;
+
+ sb = kzalloc_node(sizeof(*sb), GFP_KERNEL, dev_to_node(hcd->self.sysdev));
+ if (!sb)
+ return NULL;
+
+ mutex_init(&sb->mutex);
+
+ /* check this device isn't already controlled via sideband */
+ spin_lock_irq(&xhci->lock);
+
+ vdev = xhci->devs[udev->slot_id];
+
+ if (!vdev || vdev->sideband) {
+ xhci_warn(xhci, "XHCI sideband for slot %d already in use\n",
+ udev->slot_id);
+ spin_unlock_irq(&xhci->lock);
+ kfree(sb);
+ return NULL;
+ }
+
+ sb->xhci = xhci;
+ sb->vdev = vdev;
+ vdev->sideband = sb;
+
+ spin_unlock_irq(&xhci->lock);
+
+ return sb;
+}
+EXPORT_SYMBOL_GPL(xhci_sideband_register);
+
+/**
+ * xhci_sideband_unregister - unregister sideband access to a usb device
+ * @sb: sideband instance to be unregistered
+ *
+ * Unregisters sideband access to a usb device and frees the sideband
+ * instance.
+ * After this the endpoint and interrupter event buffers should no longer
+ * be accessed via sideband. The xhci driver can now take over handling
+ * the buffers.
+ */
+void
+xhci_sideband_unregister(struct xhci_sideband *sb)
+{
+ struct xhci_hcd *xhci = sb->xhci;
+ int i;
+
+ mutex_lock(&sb->mutex);
+ for (i = 0; i < EP_CTX_PER_DEV; i++)
+ if (sb->eps[i])
+ __xhci_sideband_remove_endpoint(sb, sb->eps[i]);
+ mutex_unlock(&sb->mutex);
+
+ xhci_sideband_remove_interrupter(sb);
+
+ spin_lock_irq(&xhci->lock);
+ sb->xhci = NULL;
+ sb->vdev->sideband = NULL;
+ spin_unlock_irq(&xhci->lock);
+
+ kfree(sb);
+}
+EXPORT_SYMBOL_GPL(xhci_sideband_unregister);
+MODULE_LICENSE("GPL");
@@ -693,6 +693,8 @@ struct xhci_virt_ep {
int next_frame_id;
/* Use new Isoch TRB layout needed for extended TBC support */
bool use_extended_tbc;
+ /* set if this endpoint is controlled via sideband access*/
+ struct xhci_sideband *sideband;
};
enum xhci_overhead_type {
@@ -756,6 +758,8 @@ struct xhci_virt_device {
u16 current_mel;
/* Used for the debugfs interfaces. */
void *debugfs_private;
+ /* set if this device is registered for sideband access */
+ struct xhci_sideband *sideband;
};
/*
new file mode 100644
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * xHCI host controller sideband support
+ *
+ * Copyright (c) 2023, Intel Corporation.
+ *
+ * Author: Mathias Nyman <mathias.nyman@linux.intel.com>
+ */
+
+#ifndef __LINUX_XHCI_SIDEBAND_H
+#define __LINUX_XHCI_SIDEBAND_H
+
+#include <linux/scatterlist.h>
+#include <linux/usb.h>
+
+#define EP_CTX_PER_DEV 31 /* FIMXME defined twice, from xhci.h */
+
+struct xhci_sideband;
+
+/**
+ * struct xhci_sideband - representation of a sideband accessed usb device.
+ * @xhci: The xhci host controller the usb device is connected to
+ * @vdev: the usb device accessed via sideband
+ * @eps: array of endpoints controlled via sideband
+ * @ir: event handling and buffer for sideband accessed device
+ *
+ * FIXME usb device accessed via sideband Keeping track of sideband accessed usb devices.
+ */
+
+struct xhci_sideband {
+ struct xhci_hcd *xhci;
+ struct xhci_virt_device *vdev;
+ struct xhci_virt_ep *eps[EP_CTX_PER_DEV];
+ struct xhci_interrupter *ir;
+ struct mutex mutex;
+};
+
+struct xhci_sideband *
+xhci_sideband_register(struct usb_device *udev);
+void
+xhci_sideband_unregister(struct xhci_sideband *sb);
+int
+xhci_sideband_add_endpoint(struct xhci_sideband *sb,
+ struct usb_host_endpoint *host_ep);
+int
+xhci_sideband_remove_endpoint(struct xhci_sideband *sb,
+ struct usb_host_endpoint *host_ep);
+int
+xhci_sideband_stop_endpoint(struct xhci_sideband *sb,
+ struct usb_host_endpoint *host_ep);
+struct sg_table *
+xhci_sideband_get_endpoint_buffer(struct xhci_sideband *sb,
+ struct usb_host_endpoint *host_ep);
+struct sg_table *
+xhci_sideband_get_event_buffer(struct xhci_sideband *sb);
+
+int
+xhci_sideband_create_interrupter(struct xhci_sideband *sb, int num_seg,
+ bool ip_autoclear);
+
+void
+xhci_sideband_remove_interrupter(struct xhci_sideband *sb);
+
+int
+xhci_sideband_interrupter_id(struct xhci_sideband *sb);
+
+#endif /* __LINUX_XHCI_SIDEBAND_H */
+