From 1cf62246c0e394021e494e0a8f1013e80db1a1a9 Mon Sep 17 00:00:00 2001 From: Sarah Sharp Date: Fri, 16 Apr 2010 08:07:04 -0700 Subject: USB: xhci: properly set the "Mult" field of the endpoint context. A SuperSpeed interrupt or isochronous endpoint can define the number of "burst transactions" it can handle in a service interval. This is indicated by the "Mult" bits in the bmAttributes of the SuperSpeed Endpoint Companion Descriptor. For example, if it has a max packet size of 1024, a max burst of 11, and a mult of 3, the host may send 33 1024-byte packets in one service interval. We must tell the xHCI host controller the number of multiple service opportunities (mults) the device can handle when the endpoint is installed. We do that by setting the Mult field of the Endpoint Context before a configure endpoint command is sent down. The Mult field is invalid for control or bulk SuperSpeed endpoints. Signed-off-by: Sarah Sharp Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci-mem.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'drivers/usb/host/xhci-mem.c') diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index c09539bad1e..4ed9f5f7a14 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -582,6 +582,19 @@ static inline unsigned int xhci_get_endpoint_interval(struct usb_device *udev, return EP_INTERVAL(interval); } +/* The "Mult" field in the endpoint context is only set for SuperSpeed devices. + * High speed endpoint descriptors can define "the number of additional + * transaction opportunities per microframe", but that goes in the Max Burst + * endpoint context field. + */ +static inline u32 xhci_get_endpoint_mult(struct usb_device *udev, + struct usb_host_endpoint *ep) +{ + if (udev->speed != USB_SPEED_SUPER || !ep->ss_ep_comp) + return 0; + return ep->ss_ep_comp->desc.bmAttributes; +} + static inline u32 xhci_get_endpoint_type(struct usb_device *udev, struct usb_host_endpoint *ep) { @@ -644,6 +657,7 @@ int xhci_endpoint_init(struct xhci_hcd *xhci, ep_ctx->deq = ep_ring->first_seg->dma | ep_ring->cycle_state; ep_ctx->ep_info = xhci_get_endpoint_interval(udev, ep); + ep_ctx->ep_info |= EP_MULT(xhci_get_endpoint_mult(udev, ep)); /* FIXME dig Mult and streams info out of ep companion desc */ -- cgit v1.2.3-70-g09d2 From 9238f25d5d32a435277eb234ec82bacdd5daed41 Mon Sep 17 00:00:00 2001 From: Sarah Sharp Date: Fri, 16 Apr 2010 08:07:27 -0700 Subject: USB: xhci: properly set endpoint context fields for periodic eps. For periodic endpoints, we must let the xHCI hardware know the maximum payload an endpoint can transfer in one service interval. The xHCI specification refers to this as the Maximum Endpoint Service Interval Time Payload (Max ESIT Payload). This is used by the hardware for bandwidth management and scheduling of packets. For SuperSpeed endpoints, the maximum is calculated by multiplying the max packet size by the number of bursts and the number of opportunities to transfer within a service interval (the Mult field of the SuperSpeed Endpoint companion descriptor). Devices advertise this in the wBytesPerInterval field of their SuperSpeed Endpoint Companion Descriptor. For high speed devices, this is taken by multiplying the max packet size by the "number of additional transaction opportunities per microframe" (the high bits of the wMaxPacketSize field in the endpoint descriptor). For FS/LS devices, this is just the max packet size. The other thing we must set in the endpoint context is the Average TRB Length. This is supposed to be the average of the total bytes in the transfer descriptor (TD), divided by the number of transfer request blocks (TRBs) it takes to describe the TD. This gives the host controller an indication of whether the driver will be enqueuing a scatter gather list with many entries comprised of small buffers, or one contiguous buffer. It also takes into account the number of extra TRBs you need for every TD. This includes No-op TRBs and Link TRBs used to link ring segments together. Some drivers may choose to chain an Event Data TRB on the end of every TD, thus increasing the average number of TRBs per TD. The Linux xHCI driver does not use Event Data TRBs. In theory, if there was an API to allow drivers to state what their bandwidth requirements are, we could set this field accurately. For now, we set it to the same number as the Max ESIT payload. The Average TRB Length should also be set for bulk and control endpoints, but I have no idea how to guess what it should be. Signed-off-by: Sarah Sharp Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci-mem.c | 51 +++++++++++++++++++++++++++++++++++++++++++++ drivers/usb/host/xhci.h | 4 ++++ 2 files changed, 55 insertions(+) (limited to 'drivers/usb/host/xhci-mem.c') diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index 4ed9f5f7a14..d64f5724bfc 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -625,6 +625,36 @@ static inline u32 xhci_get_endpoint_type(struct usb_device *udev, return type; } +/* Return the maximum endpoint service interval time (ESIT) payload. + * Basically, this is the maxpacket size, multiplied by the burst size + * and mult size. + */ +static inline u32 xhci_get_max_esit_payload(struct xhci_hcd *xhci, + struct usb_device *udev, + struct usb_host_endpoint *ep) +{ + int max_burst; + int max_packet; + + /* Only applies for interrupt or isochronous endpoints */ + if (usb_endpoint_xfer_control(&ep->desc) || + usb_endpoint_xfer_bulk(&ep->desc)) + return 0; + + if (udev->speed == USB_SPEED_SUPER) { + if (ep->ss_ep_comp) + return ep->ss_ep_comp->desc.wBytesPerInterval; + xhci_warn(xhci, "WARN no SS endpoint companion descriptor.\n"); + /* Assume no bursts, no multiple opportunities to send. */ + return ep->desc.wMaxPacketSize; + } + + max_packet = ep->desc.wMaxPacketSize & 0x3ff; + max_burst = (ep->desc.wMaxPacketSize & 0x1800) >> 11; + /* A 0 in max burst means 1 transfer per ESIT */ + return max_packet * (max_burst + 1); +} + int xhci_endpoint_init(struct xhci_hcd *xhci, struct xhci_virt_device *virt_dev, struct usb_device *udev, @@ -636,6 +666,7 @@ int xhci_endpoint_init(struct xhci_hcd *xhci, struct xhci_ring *ep_ring; unsigned int max_packet; unsigned int max_burst; + u32 max_esit_payload; ep_index = xhci_get_endpoint_index(&ep->desc); ep_ctx = xhci_get_ep_ctx(xhci, virt_dev->in_ctx, ep_index); @@ -703,6 +734,26 @@ int xhci_endpoint_init(struct xhci_hcd *xhci, default: BUG(); } + max_esit_payload = xhci_get_max_esit_payload(xhci, udev, ep); + ep_ctx->tx_info = MAX_ESIT_PAYLOAD_FOR_EP(max_esit_payload); + + /* + * XXX no idea how to calculate the average TRB buffer length for bulk + * endpoints, as the driver gives us no clue how big each scatter gather + * list entry (or buffer) is going to be. + * + * For isochronous and interrupt endpoints, we set it to the max + * available, until we have new API in the USB core to allow drivers to + * declare how much bandwidth they actually need. + * + * Normally, it would be calculated by taking the total of the buffer + * lengths in the TD and then dividing by the number of TRBs in a TD, + * including link TRBs, No-op TRBs, and Event data TRBs. Since we don't + * use Event Data TRBs, and we don't chain in a link TRB on short + * transfers, we're basically dividing by 1. + */ + ep_ctx->tx_info |= AVG_TRB_LENGTH_FOR_EP(max_esit_payload); + /* FIXME Debug endpoint context */ return 0; } diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index e5eb09b2f38..ea389e9a493 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -609,6 +609,10 @@ struct xhci_ep_ctx { #define MAX_PACKET_MASK (0xffff << 16) #define MAX_PACKET_DECODED(p) (((p) >> 16) & 0xffff) +/* tx_info bitmasks */ +#define AVG_TRB_LENGTH_FOR_EP(p) ((p) & 0xffff) +#define MAX_ESIT_PAYLOAD_FOR_EP(p) (((p) & 0xffff) << 16) + /** * struct xhci_input_control_context -- cgit v1.2.3-70-g09d2