From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752124AbcGRSkt (ORCPT ); Mon, 18 Jul 2016 14:40:49 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:35373 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751705AbcGRSkn (ORCPT ); Mon, 18 Jul 2016 14:40:43 -0400 From: Sinan Kaya To: dmaengine@vger.kernel.org, timur@codeaurora.org, devicetree@vger.kernel.org, cov@codeaurora.org, vinod.koul@intel.com, jcm@redhat.com Cc: eric.auger@linaro.org, agross@codeaurora.org, arnd@arndb.de, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Sinan Kaya , Dan Williams , Andy Shevchenko , linux-kernel@vger.kernel.org Subject: [PATCH 07/10] dmaengine: qcom_hidma: eliminate processed variables Date: Mon, 18 Jul 2016 14:39:34 -0400 Message-Id: <1468867177-15007-8-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 1.8.2.1 In-Reply-To: <1468867177-15007-1-git-send-email-okaya@codeaurora.org> References: <1468867177-15007-1-git-send-email-okaya@codeaurora.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Instead of tracking the read/write pointers in SW, track the current state by reading from HW directly. This is an attempt to eliminate potential race conditions. Signed-off-by: Sinan Kaya --- drivers/dma/qcom/hidma.h | 5 +++-- drivers/dma/qcom/hidma_dbg.c | 6 ++++-- drivers/dma/qcom/hidma_ll.c | 29 +++++++---------------------- 3 files changed, 14 insertions(+), 26 deletions(-) diff --git a/drivers/dma/qcom/hidma.h b/drivers/dma/qcom/hidma.h index 158bf1f..03c20f6 100644 --- a/drivers/dma/qcom/hidma.h +++ b/drivers/dma/qcom/hidma.h @@ -28,6 +28,9 @@ #define HIDMA_TRE_DEST_LOW_IDX 4 #define HIDMA_TRE_DEST_HI_IDX 5 +#define HIDMA_EVCA_READ_PTR_REG 0x018 +#define HIDMA_TRCA_READ_PTR_REG 0x018 + struct hidma_tre { atomic_t allocated; /* if this channel is allocated */ bool queued; /* flag whether this is pending */ @@ -63,12 +66,10 @@ struct hidma_lldev { void *tre_ring; /* TRE ring */ dma_addr_t tre_dma; /* TRE ring to be shared with HW */ u32 tre_ring_size; /* Byte size of the ring */ - u32 tre_processed_off; /* last processed TRE */ void *evre_ring; /* EVRE ring */ dma_addr_t evre_dma; /* EVRE ring to be shared with HW */ u32 evre_ring_size; /* Byte size of the ring */ - u32 evre_processed_off; /* last processed EVRE */ u32 tre_write_offset; /* TRE write location */ struct tasklet_struct task; /* task delivering notifications */ diff --git a/drivers/dma/qcom/hidma_dbg.c b/drivers/dma/qcom/hidma_dbg.c index 87db285..d741b9d 100644 --- a/drivers/dma/qcom/hidma_dbg.c +++ b/drivers/dma/qcom/hidma_dbg.c @@ -73,14 +73,16 @@ static void hidma_ll_devstats(struct seq_file *s, void *llhndl) seq_printf(s, "tre_ring=%p\n", lldev->tre_ring); 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, "tre_processed_off = 0x%x\n", + readl(lldev->trca + HIDMA_TRCA_READ_PTR_REG)); 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); seq_printf(s, "evre_ring_size = 0x%x\n", lldev->evre_ring_size); - seq_printf(s, "evre_processed_off = 0x%x\n", lldev->evre_processed_off); + seq_printf(s, "evre_processed_off = 0x%x\n", + readl(lldev->evca + HIDMA_EVCA_READ_PTR_REG)); seq_printf(s, "tre_write_offset = 0x%x\n", lldev->tre_write_offset); } diff --git a/drivers/dma/qcom/hidma_ll.c b/drivers/dma/qcom/hidma_ll.c index a71f0c7..2753210 100644 --- a/drivers/dma/qcom/hidma_ll.c +++ b/drivers/dma/qcom/hidma_ll.c @@ -245,13 +245,13 @@ static int hidma_handle_tre_completion(struct hidma_lldev *lldev, u8 err_info, u8 err_code) { u32 evre_ring_size = lldev->evre_ring_size; - u32 tre_ring_size = lldev->tre_ring_size; + u32 evre_write_off; u32 tre_iterator, evre_iterator; u32 num_completed = 0; evre_write_off = readl_relaxed(lldev->evca + HIDMA_EVCA_WRITE_PTR_REG); - tre_iterator = lldev->tre_processed_off; - evre_iterator = lldev->evre_processed_off; + evre_iterator = readl_relaxed(lldev->evca + HIDMA_EVCA_READ_PTR_REG); + tre_iterator = (evre_iterator / HIDMA_EVRE_SIZE) * HIDMA_TRE_SIZE; if ((evre_write_off > evre_ring_size) || (evre_write_off % HIDMA_EVRE_SIZE)) { @@ -280,10 +280,10 @@ static int hidma_handle_tre_completion(struct hidma_lldev *lldev, u8 err_info, err_code)) break; - HIDMA_INCREMENT_ITERATOR(tre_iterator, HIDMA_TRE_SIZE, - tre_ring_size); HIDMA_INCREMENT_ITERATOR(evre_iterator, HIDMA_EVRE_SIZE, evre_ring_size); + tre_iterator = (evre_iterator / HIDMA_EVRE_SIZE) * + HIDMA_TRE_SIZE; /* * Read the new event descriptor written by the HW. @@ -295,21 +295,8 @@ static int hidma_handle_tre_completion(struct hidma_lldev *lldev, u8 err_info, num_completed++; } - if (num_completed) { - u32 evre_read_off = (lldev->evre_processed_off + - HIDMA_EVRE_SIZE * num_completed); - u32 tre_read_off = (lldev->tre_processed_off + - HIDMA_TRE_SIZE * num_completed); - - evre_read_off = evre_read_off % evre_ring_size; - tre_read_off = tre_read_off % tre_ring_size; - - writel(evre_read_off, lldev->evca + HIDMA_EVCA_DOORBELL_REG); - - /* record the last processed tre offset */ - lldev->tre_processed_off = tre_read_off; - lldev->evre_processed_off = evre_read_off; - } + if (num_completed) + writel(evre_iterator, lldev->evca + HIDMA_EVCA_DOORBELL_REG); return num_completed; } @@ -654,8 +641,6 @@ int hidma_ll_setup(struct hidma_lldev *lldev) u32 nr_tres = lldev->nr_tres; atomic_set(&lldev->pending_tre_count, 0); - lldev->tre_processed_off = 0; - lldev->evre_processed_off = 0; lldev->tre_write_offset = 0; /* disable interrupts */ -- 1.8.2.1