Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756048AbdIRPd4 (ORCPT ); Mon, 18 Sep 2017 11:33:56 -0400 Received: from mga03.intel.com ([134.134.136.65]:52721 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755418AbdIRPbC (ORCPT ); Mon, 18 Sep 2017 11:31:02 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.42,413,1500966000"; d="scan'208";a="1196300395" From: Mika Westerberg To: Greg Kroah-Hartman , "David S . Miller" Cc: Andreas Noever , Michael Jamet , Yehezkel Bernat , Amir Levy , Mario.Limonciello@dell.com, Lukas Wunner , Andy Shevchenko , Mika Westerberg , linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH 13/16] thunderbolt: Add polling mode for rings Date: Mon, 18 Sep 2017 18:30:46 +0300 Message-Id: <20170918153049.44185-14-mika.westerberg@linux.intel.com> X-Mailer: git-send-email 2.14.1 In-Reply-To: <20170918153049.44185-1-mika.westerberg@linux.intel.com> References: <20170918153049.44185-1-mika.westerberg@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10417 Lines: 306 In order to support things like networking over Thunderbolt cable, there needs to be a way to switch the ring to a mode where it can be polled with the interrupt masked. We implement such mode so that the caller can allocate a ring by passing pointer to a function that is then called when an interrupt is triggered. Completed frames can be fetched using tb_ring_poll() and the interrupt can be re-enabled when the caller is finished with polling by using tb_ring_poll_complete(). Signed-off-by: Mika Westerberg Reviewed-by: Michael Jamet Reviewed-by: Yehezkel Bernat --- drivers/thunderbolt/ctl.c | 2 +- drivers/thunderbolt/nhi.c | 126 ++++++++++++++++++++++++++++++++++++++++---- include/linux/thunderbolt.h | 23 +++++--- 3 files changed, 134 insertions(+), 17 deletions(-) diff --git a/drivers/thunderbolt/ctl.c b/drivers/thunderbolt/ctl.c index dd10789e1dbb..d079dbba2c03 100644 --- a/drivers/thunderbolt/ctl.c +++ b/drivers/thunderbolt/ctl.c @@ -619,7 +619,7 @@ struct tb_ctl *tb_ctl_alloc(struct tb_nhi *nhi, event_cb cb, void *cb_data) goto err; ctl->rx = tb_ring_alloc_rx(nhi, 0, 10, RING_FLAG_NO_SUSPEND, 0xffff, - 0xffff); + 0xffff, NULL, NULL); if (!ctl->rx) goto err; diff --git a/drivers/thunderbolt/nhi.c b/drivers/thunderbolt/nhi.c index cf1397afa72f..5bc3f77cc1f3 100644 --- a/drivers/thunderbolt/nhi.c +++ b/drivers/thunderbolt/nhi.c @@ -252,7 +252,8 @@ static void ring_work(struct work_struct *work) * Do not hold on to it. */ list_del_init(&frame->list); - frame->callback(ring, frame, canceled); + if (frame->callback) + frame->callback(ring, frame, canceled); } } @@ -273,11 +274,106 @@ int __tb_ring_enqueue(struct tb_ring *ring, struct ring_frame *frame) } EXPORT_SYMBOL_GPL(__tb_ring_enqueue); +/** + * tb_ring_poll() - Poll one completed frame from the ring + * @ring: Ring to poll + * + * This function can be called when @start_poll callback of the @ring + * has been called. It will read one completed frame from the ring and + * return it to the caller. Returns %NULL if there is no more completed + * frames. + */ +struct ring_frame *tb_ring_poll(struct tb_ring *ring) +{ + struct ring_frame *frame = NULL; + unsigned long flags; + + spin_lock_irqsave(&ring->lock, flags); + if (!ring->running) + goto unlock; + if (ring_empty(ring)) + goto unlock; + + if (ring->descriptors[ring->tail].flags & RING_DESC_COMPLETED) { + frame = list_first_entry(&ring->in_flight, typeof(*frame), + list); + list_del_init(&frame->list); + + if (!ring->is_tx) { + frame->size = ring->descriptors[ring->tail].length; + frame->eof = ring->descriptors[ring->tail].eof; + frame->sof = ring->descriptors[ring->tail].sof; + frame->flags = ring->descriptors[ring->tail].flags; + } + + ring->tail = (ring->tail + 1) % ring->size; + } + +unlock: + spin_unlock_irqrestore(&ring->lock, flags); + return frame; +} +EXPORT_SYMBOL_GPL(tb_ring_poll); + +static void __ring_interrupt_mask(struct tb_ring *ring, bool mask) +{ + int idx = ring_interrupt_index(ring); + int reg = REG_RING_INTERRUPT_BASE + idx / 32 * 4; + int bit = idx % 32; + u32 val; + + val = ioread32(ring->nhi->iobase + reg); + if (mask) + val &= ~BIT(bit); + else + val |= BIT(bit); + iowrite32(val, ring->nhi->iobase + reg); +} + +/* Both @nhi->lock and @ring->lock should be held */ +static void __ring_interrupt(struct tb_ring *ring) +{ + if (!ring->running) + return; + + if (ring->start_poll) { + __ring_interrupt_mask(ring, false); + ring->start_poll(ring->poll_data); + } else { + schedule_work(&ring->work); + } +} + +/** + * tb_ring_poll_complete() - Re-start interrupt for the ring + * @ring: Ring to re-start the interrupt + * + * This will re-start (unmask) the ring interrupt once the user is done + * with polling. + */ +void tb_ring_poll_complete(struct tb_ring *ring) +{ + unsigned long flags; + + spin_lock_irqsave(&ring->nhi->lock, flags); + spin_lock(&ring->lock); + if (ring->start_poll) + __ring_interrupt_mask(ring, false); + spin_unlock(&ring->lock); + spin_unlock_irqrestore(&ring->nhi->lock, flags); +} +EXPORT_SYMBOL_GPL(tb_ring_poll_complete); + static irqreturn_t ring_msix(int irq, void *data) { struct tb_ring *ring = data; - schedule_work(&ring->work); + spin_lock(&ring->nhi->lock); + spin_lock(&ring->lock); + __ring_interrupt(ring); + spin_unlock(&ring->lock); + spin_unlock(&ring->nhi->lock); + return IRQ_HANDLED; } @@ -317,7 +413,9 @@ static void ring_release_msix(struct tb_ring *ring) static struct tb_ring *tb_ring_alloc(struct tb_nhi *nhi, u32 hop, int size, bool transmit, unsigned int flags, - u16 sof_mask, u16 eof_mask) + u16 sof_mask, u16 eof_mask, + void (*start_poll)(void *), + void *poll_data) { struct tb_ring *ring = NULL; dev_info(&nhi->pdev->dev, "allocating %s ring %d of size %d\n", @@ -346,6 +444,8 @@ static struct tb_ring *tb_ring_alloc(struct tb_nhi *nhi, u32 hop, int size, ring->head = 0; ring->tail = 0; ring->running = false; + ring->start_poll = start_poll; + ring->poll_data = poll_data; ring->descriptors = dma_alloc_coherent(&ring->nhi->pdev->dev, size * sizeof(*ring->descriptors), @@ -399,7 +499,7 @@ static struct tb_ring *tb_ring_alloc(struct tb_nhi *nhi, u32 hop, int size, struct tb_ring *tb_ring_alloc_tx(struct tb_nhi *nhi, int hop, int size, unsigned int flags) { - return tb_ring_alloc(nhi, hop, size, true, flags, 0, 0); + return tb_ring_alloc(nhi, hop, size, true, flags, 0, 0, NULL, NULL); } EXPORT_SYMBOL_GPL(tb_ring_alloc_tx); @@ -411,11 +511,17 @@ EXPORT_SYMBOL_GPL(tb_ring_alloc_tx); * @flags: Flags for the ring * @sof_mask: Mask of PDF values that start a frame * @eof_mask: Mask of PDF values that end a frame + * @start_poll: If not %NULL the ring will call this function when an + * interrupt is triggered and masked, instead of callback + * in each Rx frame. + * @poll_data: Optional data passed to @start_poll */ struct tb_ring *tb_ring_alloc_rx(struct tb_nhi *nhi, int hop, int size, - unsigned int flags, u16 sof_mask, u16 eof_mask) + unsigned int flags, u16 sof_mask, u16 eof_mask, + void (*start_poll)(void *), void *poll_data) { - return tb_ring_alloc(nhi, hop, size, false, flags, sof_mask, eof_mask); + return tb_ring_alloc(nhi, hop, size, false, flags, sof_mask, eof_mask, + start_poll, poll_data); } EXPORT_SYMBOL_GPL(tb_ring_alloc_rx); @@ -556,6 +662,7 @@ void tb_ring_free(struct tb_ring *ring) dev_WARN(&ring->nhi->pdev->dev, "%s %d still running\n", RING_TYPE(ring), ring->hop); } + spin_unlock_irq(&ring->nhi->lock); ring_release_msix(ring); @@ -572,7 +679,6 @@ void tb_ring_free(struct tb_ring *ring) RING_TYPE(ring), ring->hop); - spin_unlock_irq(&ring->nhi->lock); /** * ring->work can no longer be scheduled (it is scheduled only * by nhi_interrupt_work, ring_stop and ring_msix). Wait for it @@ -682,8 +788,10 @@ static void nhi_interrupt_work(struct work_struct *work) hop); continue; } - /* we do not check ring->running, this is done in ring->work */ - schedule_work(&ring->work); + + spin_lock(&ring->lock); + __ring_interrupt(ring); + spin_unlock(&ring->lock); } spin_unlock_irq(&nhi->lock); } diff --git a/include/linux/thunderbolt.h b/include/linux/thunderbolt.h index 62adb97d77f1..9a63210d5084 100644 --- a/include/linux/thunderbolt.h +++ b/include/linux/thunderbolt.h @@ -446,6 +446,9 @@ struct tb_nhi { * @flags: Ring specific flags * @sof_mask: Bit mask used to detect start of frame PDF * @eof_mask: Bit mask used to detect end of frame PDF + * @start_poll: Called when ring interrupt is triggered to start + * polling. Passing %NULL keeps the ring in interrupt mode. + * @poll_data: Data passed to @start_poll */ struct tb_ring { spinlock_t lock; @@ -466,6 +469,8 @@ struct tb_ring { unsigned int flags; u16 sof_mask; u16 eof_mask; + void (*start_poll)(void *data); + void *poll_data; }; /* Leave ring interrupt enabled on suspend */ @@ -499,7 +504,7 @@ enum ring_desc_flags { /** * struct ring_frame - For use with ring_rx/ring_tx * @buffer_phy: DMA mapped address of the frame - * @callback: Callback called when the frame is finished + * @callback: Callback called when the frame is finished (optional) * @list: Frame is linked to a queue using this * @size: Size of the frame in bytes (%0 means %4096) * @flags: Flags for the frame (see &enum ring_desc_flags) @@ -522,8 +527,8 @@ struct ring_frame { struct tb_ring *tb_ring_alloc_tx(struct tb_nhi *nhi, int hop, int size, unsigned int flags); struct tb_ring *tb_ring_alloc_rx(struct tb_nhi *nhi, int hop, int size, - unsigned int flags, u16 sof_mask, - u16 eof_mask); + unsigned int flags, u16 sof_mask, u16 eof_mask, + void (*start_poll)(void *), void *poll_data); void tb_ring_start(struct tb_ring *ring); void tb_ring_stop(struct tb_ring *ring); void tb_ring_free(struct tb_ring *ring); @@ -535,8 +540,8 @@ int __tb_ring_enqueue(struct tb_ring *ring, struct ring_frame *frame); * @ring: Ring to enqueue the frame * @frame: Frame to enqueue * - * @frame->buffer, @frame->buffer_phy and @frame->callback have to be set. The - * buffer must contain at least %TB_FRAME_SIZE bytes. + * @frame->buffer, @frame->buffer_phy have to be set. The buffer must + * contain at least %TB_FRAME_SIZE bytes. * * @frame->callback will be invoked with @frame->size, @frame->flags, * @frame->eof, @frame->sof set once the frame has been received. @@ -557,8 +562,8 @@ static inline int tb_ring_rx(struct tb_ring *ring, struct ring_frame *frame) * @ring: Ring the enqueue the frame * @frame: Frame to enqueue * - * @frame->buffer, @frame->buffer_phy, @frame->callback, @frame->size, - * @frame->eof and @frame->sof have to be set. + * @frame->buffer, @frame->buffer_phy, @frame->size, @frame->eof and + * @frame->sof have to be set. * * @frame->callback will be invoked with once the frame has been transmitted. * @@ -573,4 +578,8 @@ static inline int tb_ring_tx(struct tb_ring *ring, struct ring_frame *frame) return __tb_ring_enqueue(ring, frame); } +/* Used only when the ring is in polling mode */ +struct ring_frame *tb_ring_poll(struct tb_ring *ring); +void tb_ring_poll_complete(struct tb_ring *ring); + #endif /* THUNDERBOLT_H_ */ -- 2.13.5