Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753451AbdFLRTN (ORCPT ); Mon, 12 Jun 2017 13:19:13 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:40128 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753377AbdFLPa1 (ORCPT ); Mon, 12 Jun 2017 11:30:27 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thomas Petazzoni , Vinod Koul Subject: [PATCH 4.11 063/150] dmaengine: mv_xor_v2: fix tx_submit() implementation Date: Mon, 12 Jun 2017 17:24:30 +0200 Message-Id: <20170612152522.119249957@linuxfoundation.org> X-Mailer: git-send-email 2.13.1 In-Reply-To: <20170612152519.404936272@linuxfoundation.org> References: <20170612152519.404936272@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2931 Lines: 88 4.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Petazzoni commit 44d5887a8bf1e86915c8ff647337cb138149da82 upstream. The mv_xor_v2_tx_submit() gets the next available HW descriptor by calling mv_xor_v2_get_desq_write_ptr(), which reads a HW register telling the next available HW descriptor. This was working fine when HW descriptors were issued for processing directly in tx_submit(). However, as part of the review process of the driver, a change was requested to move the actual kick-off of HW descriptors processing to ->issue_pending(). Due to this, reading the HW register to know the next available HW descriptor no longer works. So instead of using this HW register, we implemented a software index pointing to the next available HW descriptor. Fixes: 19a340b1a820 ("dmaengine: mv_xor_v2: new driver") Signed-off-by: Thomas Petazzoni Signed-off-by: Vinod Koul Signed-off-by: Greg Kroah-Hartman --- drivers/dma/mv_xor_v2.c | 22 +++++----------------- 1 file changed, 5 insertions(+), 17 deletions(-) --- a/drivers/dma/mv_xor_v2.c +++ b/drivers/dma/mv_xor_v2.c @@ -161,6 +161,7 @@ struct mv_xor_v2_device { struct mv_xor_v2_sw_desc *sw_desq; int desc_size; unsigned int npendings; + unsigned int hw_queue_idx; }; /** @@ -214,18 +215,6 @@ static void mv_xor_v2_set_data_buffers(s } /* - * Return the next available index in the DESQ. - */ -static int mv_xor_v2_get_desq_write_ptr(struct mv_xor_v2_device *xor_dev) -{ - /* read the index for the next available descriptor in the DESQ */ - u32 reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_ALLOC_OFF); - - return ((reg >> MV_XOR_V2_DMA_DESQ_ALLOC_WRPTR_SHIFT) - & MV_XOR_V2_DMA_DESQ_ALLOC_WRPTR_MASK); -} - -/* * notify the engine of new descriptors, and update the available index. */ static void mv_xor_v2_add_desc_to_desq(struct mv_xor_v2_device *xor_dev, @@ -306,7 +295,6 @@ static irqreturn_t mv_xor_v2_interrupt_h static dma_cookie_t mv_xor_v2_tx_submit(struct dma_async_tx_descriptor *tx) { - int desq_ptr; void *dest_hw_desc; dma_cookie_t cookie; struct mv_xor_v2_sw_desc *sw_desc = @@ -322,15 +310,15 @@ mv_xor_v2_tx_submit(struct dma_async_tx_ spin_lock_bh(&xor_dev->lock); cookie = dma_cookie_assign(tx); - /* get the next available slot in the DESQ */ - desq_ptr = mv_xor_v2_get_desq_write_ptr(xor_dev); - /* copy the HW descriptor from the SW descriptor to the DESQ */ - dest_hw_desc = xor_dev->hw_desq_virt + desq_ptr; + dest_hw_desc = xor_dev->hw_desq_virt + xor_dev->hw_queue_idx; memcpy(dest_hw_desc, &sw_desc->hw_desc, xor_dev->desc_size); xor_dev->npendings++; + xor_dev->hw_queue_idx++; + if (xor_dev->hw_queue_idx >= MV_XOR_V2_DESC_NUM) + xor_dev->hw_queue_idx = 0; spin_unlock_bh(&xor_dev->lock);