From 140ca4cfea8a7aeff89c8969a4cc7ce125a04159 Mon Sep 17 00:00:00 2001 From: Thinh Nguyen Date: Tue, 5 May 2020 19:47:09 -0700 Subject: usb: dwc3: gadget: Handle stream transfers Overview of stream transfer requirement: * A transfer will have a set of TRBs of the same stream ID. * A transfer is started with a stream ID in START_TRANSFER command. * A new stream will only start when the previous completes. Overview of stream events: * A "prime" from host indicates that its endpoints are active (buffers prepared and ready to receive/transmit data). The controller automatically initiates stream if it sees this. * A "NoStream" rejection event indicates that the host isn't ready. Host will put the endpoint back to idle state. Device may need to reinitiate the stream to start transfer again. * A Stream Found event means host accepted device initiated stream. Nothing needs to be done from driver. To initiate a stream, the driver will issue START_TRANSFER command with a stream ID. To reinitiate the stream, the driver must issue END_TRANSFER and restart the transfer with START_TRANSFER command with the same stream ID. This implementation handles device-initated streams (e.g. UASP driver). It also handles some hosts' quirky behavior where they only prime each endpoint once. Signed-off-by: Thinh Nguyen Signed-off-by: Felipe Balbi --- drivers/usb/dwc3/core.h | 8 ++++ drivers/usb/dwc3/debug.h | 2 + drivers/usb/dwc3/gadget.c | 97 +++++++++++++++++++++++++++++++++++++++++++++-- 3 files changed, 104 insertions(+), 3 deletions(-) (limited to 'drivers/usb') diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h index b11183a715a7..4def088329c7 100644 --- a/drivers/usb/dwc3/core.h +++ b/drivers/usb/dwc3/core.h @@ -495,6 +495,7 @@ #define DWC3_DGCMD_SELECTED_FIFO_FLUSH 0x09 #define DWC3_DGCMD_ALL_FIFO_FLUSH 0x0a #define DWC3_DGCMD_SET_ENDPOINT_NRDY 0x0c +#define DWC3_DGCMD_SET_ENDPOINT_PRIME 0x0d #define DWC3_DGCMD_RUN_SOC_BUS_LOOPBACK 0x10 #define DWC3_DGCMD_STATUS(n) (((n) >> 12) & 0x0F) @@ -702,6 +703,9 @@ struct dwc3_ep { #define DWC3_EP_PENDING_REQUEST BIT(5) #define DWC3_EP_DELAY_START BIT(6) #define DWC3_EP_WAIT_TRANSFER_COMPLETE BIT(7) +#define DWC3_EP_IGNORE_NEXT_NOSTREAM BIT(8) +#define DWC3_EP_FORCE_RESTART_STREAM BIT(9) +#define DWC3_EP_FIRST_STREAM_PRIMED BIT(10) /* This last one is specific to EP0 */ #define DWC3_EP0_DIR_IN BIT(31) @@ -1301,6 +1305,10 @@ struct dwc3_event_depevt { #define DEPEVT_STREAMEVT_FOUND 1 #define DEPEVT_STREAMEVT_NOTFOUND 2 +/* Stream event parameter */ +#define DEPEVT_STREAM_PRIME 0xfffe +#define DEPEVT_STREAM_NOSTREAM 0x0 + /* Control-only Status */ #define DEPEVT_STATUS_CONTROL_DATA 1 #define DEPEVT_STATUS_CONTROL_STATUS 2 diff --git a/drivers/usb/dwc3/debug.h b/drivers/usb/dwc3/debug.h index 0f95656c9622..d8f600e0e88f 100644 --- a/drivers/usb/dwc3/debug.h +++ b/drivers/usb/dwc3/debug.h @@ -68,6 +68,8 @@ dwc3_gadget_generic_cmd_string(u8 cmd) return "All FIFO Flush"; case DWC3_DGCMD_SET_ENDPOINT_NRDY: return "Set Endpoint NRDY"; + case DWC3_DGCMD_SET_ENDPOINT_PRIME: + return "Set Endpoint Prime"; case DWC3_DGCMD_RUN_SOC_BUS_LOOPBACK: return "Run SoC Bus Loopback Test"; default: diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 07824b670440..0380f76151a1 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -610,6 +610,9 @@ static int dwc3_gadget_set_ep_config(struct dwc3_ep *dep, unsigned int action) return dwc3_send_gadget_ep_cmd(dep, DWC3_DEPCMD_SETEPCONFIG, ¶ms); } +static void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force, + bool interrupt); + /** * __dwc3_gadget_ep_enable - initializes a hw endpoint * @dep: endpoint to be initialized @@ -670,7 +673,7 @@ static int __dwc3_gadget_ep_enable(struct dwc3_ep *dep, unsigned int action) * Issue StartTransfer here with no-op TRB so we can always rely on No * Response Update Transfer command. */ - if ((usb_endpoint_xfer_bulk(desc) && !dep->stream_capable) || + if (usb_endpoint_xfer_bulk(desc) || usb_endpoint_xfer_int(desc)) { struct dwc3_gadget_ep_cmd_params params; struct dwc3_trb *trb; @@ -689,6 +692,29 @@ static int __dwc3_gadget_ep_enable(struct dwc3_ep *dep, unsigned int action) ret = dwc3_send_gadget_ep_cmd(dep, cmd, ¶ms); if (ret < 0) return ret; + + if (dep->stream_capable) { + /* + * For streams, at start, there maybe a race where the + * host primes the endpoint before the function driver + * queues a request to initiate a stream. In that case, + * the controller will not see the prime to generate the + * ERDY and start stream. To workaround this, issue a + * no-op TRB as normal, but end it immediately. As a + * result, when the function driver queues the request, + * the next START_TRANSFER command will cause the + * controller to generate an ERDY to initiate the + * stream. + */ + dwc3_stop_active_transfer(dep, true, true); + + /* + * All stream eps will reinitiate stream on NoStream + * rejection until we can determine that the host can + * prime after the first transfer. + */ + dep->flags |= DWC3_EP_FORCE_RESTART_STREAM; + } } out: @@ -697,8 +723,6 @@ out: return 0; } -static void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force, - bool interrupt); static void dwc3_remove_requests(struct dwc3 *dwc, struct dwc3_ep *dep) { struct dwc3_request *req; @@ -2772,6 +2796,63 @@ static void dwc3_gadget_endpoint_transfer_not_ready(struct dwc3_ep *dep, (void) __dwc3_gadget_start_isoc(dep); } +static void dwc3_gadget_endpoint_stream_event(struct dwc3_ep *dep, + const struct dwc3_event_depevt *event) +{ + struct dwc3 *dwc = dep->dwc; + + if (event->status == DEPEVT_STREAMEVT_FOUND) { + dep->flags |= DWC3_EP_FIRST_STREAM_PRIMED; + goto out; + } + + /* Note: NoStream rejection event param value is 0 and not 0xFFFF */ + switch (event->parameters) { + case DEPEVT_STREAM_PRIME: + /* + * If the host can properly transition the endpoint state from + * idle to prime after a NoStream rejection, there's no need to + * force restarting the endpoint to reinitiate the stream. To + * simplify the check, assume the host follows the USB spec if + * it primed the endpoint more than once. + */ + if (dep->flags & DWC3_EP_FORCE_RESTART_STREAM) { + if (dep->flags & DWC3_EP_FIRST_STREAM_PRIMED) + dep->flags &= ~DWC3_EP_FORCE_RESTART_STREAM; + else + dep->flags |= DWC3_EP_FIRST_STREAM_PRIMED; + } + + break; + case DEPEVT_STREAM_NOSTREAM: + if ((dep->flags & DWC3_EP_IGNORE_NEXT_NOSTREAM) || + !(dep->flags & DWC3_EP_FORCE_RESTART_STREAM) || + !(dep->flags & DWC3_EP_WAIT_TRANSFER_COMPLETE)) + break; + + /* + * If the host rejects a stream due to no active stream, by the + * USB and xHCI spec, the endpoint will be put back to idle + * state. When the host is ready (buffer added/updated), it will + * prime the endpoint to inform the usb device controller. This + * triggers the device controller to issue ERDY to restart the + * stream. However, some hosts don't follow this and keep the + * endpoint in the idle state. No prime will come despite host + * streams are updated, and the device controller will not be + * triggered to generate ERDY to move the next stream data. To + * workaround this and maintain compatibility with various + * hosts, force to reinitate the stream until the host is ready + * instead of waiting for the host to prime the endpoint. + */ + dep->flags |= DWC3_EP_DELAY_START; + dwc3_stop_active_transfer(dep, true, true); + return; + } + +out: + dep->flags &= ~DWC3_EP_IGNORE_NEXT_NOSTREAM; +} + static void dwc3_endpoint_interrupt(struct dwc3 *dwc, const struct dwc3_event_depevt *event) { @@ -2820,6 +2901,8 @@ static void dwc3_endpoint_interrupt(struct dwc3 *dwc, dwc3_gadget_endpoint_transfer_complete(dep, event); break; case DWC3_DEPEVT_STREAMEVT: + dwc3_gadget_endpoint_stream_event(dep, event); + break; case DWC3_DEPEVT_RXTXFIFOEVT: break; } @@ -2911,6 +2994,14 @@ static void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force, WARN_ON_ONCE(ret); dep->resource_index = 0; + /* + * The END_TRANSFER command will cause the controller to generate a + * NoStream Event, and it's not due to the host DP NoStream rejection. + * Ignore the next NoStream event. + */ + if (dep->stream_capable) + dep->flags |= DWC3_EP_IGNORE_NEXT_NOSTREAM; + if (!interrupt) dep->flags &= ~DWC3_EP_TRANSFER_STARTED; else -- cgit v1.2.3