From: Vinod Koul <vinod.koul@intel.com>
To: Sinan Kaya <okaya@codeaurora.org>
Cc: dmaengine@vger.kernel.org, timur@codeaurora.org,
devicetree@vger.kernel.org, cov@codeaurora.org, jcm@redhat.com,
agross@codeaurora.org, arnd@arndb.de,
linux-arm-msm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Dan Williams <dan.j.williams@intel.com>,
Andy Shevchenko <andy.shevchenko@gmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH V4 05/10] dmaengine: qcom_hidma: make pending_tre_count atomic
Date: Sat, 1 Oct 2016 11:49:06 +0530 [thread overview]
Message-ID: <20161001061906.GG2467@localhost> (raw)
In-Reply-To: <1475115167-5898-6-git-send-email-okaya@codeaurora.org>
On Wed, Sep 28, 2016 at 10:12:42PM -0400, Sinan Kaya wrote:
> Getting ready for the MSI interrupts. The pending_tre_count is used
> in the interrupt handler to make sure all outstanding requests are
> serviced.
>
> Making it atomic so that it can be updated from multiple contexts.
How is it multiple contexts? It's either existing context of MSI, not both!
>
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> ---
> drivers/dma/qcom/hidma.h | 2 +-
> drivers/dma/qcom/hidma_dbg.c | 3 ++-
> drivers/dma/qcom/hidma_ll.c | 13 ++++++-------
> 3 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/dma/qcom/hidma.h b/drivers/dma/qcom/hidma.h
> index e52e207..3f2ddd4 100644
> --- a/drivers/dma/qcom/hidma.h
> +++ b/drivers/dma/qcom/hidma.h
> @@ -58,7 +58,7 @@ struct hidma_lldev {
> void __iomem *evca; /* Event Channel address */
> struct hidma_tre
> **pending_tre_list; /* Pointers to pending TREs */
> - s32 pending_tre_count; /* Number of TREs pending */
> + atomic_t pending_tre_count; /* Number of TREs pending */
>
> void *tre_ring; /* TRE ring */
> dma_addr_t tre_dma; /* TRE ring to be shared with HW */
> diff --git a/drivers/dma/qcom/hidma_dbg.c b/drivers/dma/qcom/hidma_dbg.c
> index fa827e5..87db285 100644
> --- a/drivers/dma/qcom/hidma_dbg.c
> +++ b/drivers/dma/qcom/hidma_dbg.c
> @@ -74,7 +74,8 @@ static void hidma_ll_devstats(struct seq_file *s, void *llhndl)
> seq_printf(s, "tre_ring_handle=%pap\n", &lldev->tre_dma);
> seq_printf(s, "tre_ring_size = 0x%x\n", lldev->tre_ring_size);
> seq_printf(s, "tre_processed_off = 0x%x\n", lldev->tre_processed_off);
> - seq_printf(s, "pending_tre_count=%d\n", lldev->pending_tre_count);
> + seq_printf(s, "pending_tre_count=%d\n",
> + atomic_read(&lldev->pending_tre_count));
> seq_printf(s, "evca=%p\n", lldev->evca);
> seq_printf(s, "evre_ring=%p\n", lldev->evre_ring);
> seq_printf(s, "evre_ring_handle=%pap\n", &lldev->evre_dma);
> diff --git a/drivers/dma/qcom/hidma_ll.c b/drivers/dma/qcom/hidma_ll.c
> index 3224f24..29fef4f 100644
> --- a/drivers/dma/qcom/hidma_ll.c
> +++ b/drivers/dma/qcom/hidma_ll.c
> @@ -218,10 +218,9 @@ static int hidma_post_completed(struct hidma_lldev *lldev, int tre_iterator,
> * Keep track of pending TREs that SW is expecting to receive
> * from HW. We got one now. Decrement our counter.
> */
> - lldev->pending_tre_count--;
> - if (lldev->pending_tre_count < 0) {
> + if (atomic_dec_return(&lldev->pending_tre_count) < 0) {
> dev_warn(lldev->dev, "tre count mismatch on completion");
> - lldev->pending_tre_count = 0;
> + atomic_set(&lldev->pending_tre_count, 0);
> }
>
> spin_unlock_irqrestore(&lldev->lock, flags);
> @@ -321,7 +320,7 @@ void hidma_cleanup_pending_tre(struct hidma_lldev *lldev, u8 err_info,
> u32 tre_read_off;
>
> tre_iterator = lldev->tre_processed_off;
> - while (lldev->pending_tre_count) {
> + while (atomic_read(&lldev->pending_tre_count)) {
> if (hidma_post_completed(lldev, tre_iterator, err_info,
> err_code))
> break;
> @@ -548,7 +547,7 @@ void hidma_ll_queue_request(struct hidma_lldev *lldev, u32 tre_ch)
> tre->err_code = 0;
> tre->err_info = 0;
> tre->queued = 1;
> - lldev->pending_tre_count++;
> + atomic_inc(&lldev->pending_tre_count);
> lldev->tre_write_offset = (lldev->tre_write_offset + HIDMA_TRE_SIZE)
> % lldev->tre_ring_size;
> spin_unlock_irqrestore(&lldev->lock, flags);
> @@ -654,7 +653,7 @@ int hidma_ll_setup(struct hidma_lldev *lldev)
> u32 val;
> u32 nr_tres = lldev->nr_tres;
>
> - lldev->pending_tre_count = 0;
> + atomic_set(&lldev->pending_tre_count, 0);
> lldev->tre_processed_off = 0;
> lldev->evre_processed_off = 0;
> lldev->tre_write_offset = 0;
> @@ -816,7 +815,7 @@ int hidma_ll_uninit(struct hidma_lldev *lldev)
> tasklet_kill(&lldev->task);
> memset(lldev->trepool, 0, required_bytes);
> lldev->trepool = NULL;
> - lldev->pending_tre_count = 0;
> + atomic_set(&lldev->pending_tre_count, 0);
> lldev->tre_write_offset = 0;
>
> rc = hidma_ll_reset(lldev);
> --
> 1.9.1
>
--
~Vinod
next prev parent reply other threads:[~2016-10-01 6:19 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-29 2:12 [PATCH V4 00/10] dmaengine: qcom_hidma: add MSI interrupt support Sinan Kaya
2016-09-29 2:12 ` [PATCH V4 02/10] Documentation: DT: qcom_hidma: correct spelling mistakes Sinan Kaya
2016-09-29 2:12 ` [PATCH V4 06/10] dmaengine: qcom_hidma: make error and success path common Sinan Kaya
2016-09-29 2:12 ` [PATCH V4 07/10] dmaengine: qcom_hidma: bring out interrupt cause Sinan Kaya
[not found] ` <1475115167-5898-1-git-send-email-okaya-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
2016-09-29 2:12 ` [PATCH V4 01/10] Documentation: DT: qcom_hidma: update binding for MSI Sinan Kaya
2016-09-29 2:12 ` [PATCH V4 03/10] of: irq: make of_msi_configure accessible from modules Sinan Kaya
2016-09-29 2:12 ` [PATCH V4 04/10] dmaengine: qcom_hidma: configure DMA and MSI for OF Sinan Kaya
2016-10-01 6:17 ` Vinod Koul
2016-10-01 15:15 ` Sinan Kaya
2016-10-03 3:38 ` Vinod Koul
2016-10-03 13:39 ` Sinan Kaya
2016-09-29 2:12 ` [PATCH V4 05/10] dmaengine: qcom_hidma: make pending_tre_count atomic Sinan Kaya
2016-10-01 6:19 ` Vinod Koul [this message]
2016-10-01 15:19 ` Sinan Kaya
2016-10-03 3:39 ` Vinod Koul
2016-09-29 2:12 ` [PATCH V4 08/10] dmaengine: qcom_hidma: add a common API to setup the interrupt Sinan Kaya
2016-09-29 2:12 ` [PATCH V4 09/10] dmaengine: qcom_hidma: protect common data structures Sinan Kaya
2016-09-29 2:12 ` [PATCH V4 10/10] dmaengine: qcom_hidma: add MSI support for interrupts Sinan Kaya
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