From patchwork Tue Oct 25 09:02:53 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tudor Ambarus X-Patchwork-Id: 13018812 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1EE9CFA373E for ; Tue, 25 Oct 2022 09:06:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232066AbiJYJGn (ORCPT ); Tue, 25 Oct 2022 05:06:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231605AbiJYJFO (ORCPT ); Tue, 25 Oct 2022 05:05:14 -0400 Received: from esa.microchip.iphmx.com (esa.microchip.iphmx.com [68.232.153.233]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9D561160858; Tue, 25 Oct 2022 02:04:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1666688650; x=1698224650; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=SMuZlI4ecQlxVAb/de+MSzVtik6fZSZ0Lzcv5HL3yGs=; b=iDjK+3CFbE3xF3wFFkgv9IQCPNmtqA5UlU/IlYDhwkYJqhU//i23eM2N pqavWa0wPrtbm+gmDJTLlN4N/kn8TiycLmqnnyq+6RfhjmhJEv70T+grq T/Q/1Bn3ObDO0LrS+RDb9QJjxM4389PwsJoWY68KxqF9EYYgN4nPUgWE/ UzAvSoAJjixzBTB2AZbDjwhpBwnV1Cjfd+qWoR9CZL72YoSFzvoNn6/Ql D0YpP7eGVJBlMMdmSljJ7vgb8ieYH0fvm/YFe7Z+4vqAeO/qLnTJF4z0p oeMmELalV+bW123AacrHx3ijbxKZQpxQDEnPcqNr3n4w2KfWPAcRjlLN1 A==; X-IronPort-AV: E=Sophos;i="5.95,211,1661842800"; d="scan'208";a="196910141" Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa1.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 25 Oct 2022 02:04:09 -0700 Received: from chn-vm-ex03.mchp-main.com (10.10.85.151) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.12; Tue, 25 Oct 2022 02:04:09 -0700 Received: from ROB-ULT-M18064N.mchp-main.com (10.10.115.15) by chn-vm-ex03.mchp-main.com (10.10.85.151) with Microsoft SMTP Server id 15.1.2507.12 via Frontend Transport; Tue, 25 Oct 2022 02:04:06 -0700 From: Tudor Ambarus To: , , CC: , , , , , , , "Tudor Ambarus" Subject: [PATCH v2 19/32] dmaengine: at_hdmac: Pass residue by address to avoid unnecessary implicit casts Date: Tue, 25 Oct 2022 12:02:53 +0300 Message-ID: <20221025090306.297886-20-tudor.ambarus@microchip.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221025090306.297886-1-tudor.ambarus@microchip.com> References: <20221025090306.297886-1-tudor.ambarus@microchip.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org struct dma_tx_state defines residue as u32. atc_get_bytes_left() returned an int which could be either an error or the value of the residue. This could cause problems if the controller supported a u32 buffer transfer size and the u32 value was past the max int can hold. Our controller does not support u32 buffer transfer size, but even so, improve the code and pass the residue by address to avoid unnecessary implicit casts and make atc_get_bytes_left() return 0 on success or -errno on errors. Signed-off-by: Tudor Ambarus --- drivers/dma/at_hdmac.c | 54 +++++++++++++++++++++++------------------- 1 file changed, 30 insertions(+), 24 deletions(-) diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index fbfb207104e9..e2c46f32b284 100644 --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -293,7 +293,7 @@ static struct at_desc *atc_get_desc_by_cookie(struct at_dma_chan *atchan, * @current_len: the number of bytes left before reading CTRLA * @ctrla: the value of CTRLA */ -static inline int atc_calc_bytes_left(int current_len, u32 ctrla) +static inline u32 atc_calc_bytes_left(u32 current_len, u32 ctrla) { u32 btsize = (ctrla & ATC_BTSIZE_MAX); u32 src_width = ATC_REG_TO_SRC_WIDTH(ctrla); @@ -308,17 +308,20 @@ static inline int atc_calc_bytes_left(int current_len, u32 ctrla) } /** - * atc_get_bytes_left - get the number of bytes residue for a cookie + * atc_get_bytes_left - get the number of bytes residue for a cookie. + * The residue is passed by address and updated on success. * @chan: DMA channel * @cookie: transaction identifier to check status of + * @residue: residue to be updated. + * Return 0 on success, -errono otherwise. */ -static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie) +static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie, + u32 *residue) { struct at_dma_chan *atchan = to_at_dma_chan(chan); struct at_desc *desc_first = atc_first_active(atchan); struct at_desc *desc; - int ret; - u32 ctrla, dscr; + u32 len, ctrla, dscr; unsigned int i; /* @@ -333,7 +336,7 @@ static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie) return desc->total_len; /* cookie matches to the currently running transfer */ - ret = desc_first->total_len; + len = desc_first->total_len; if (desc_first->lli.dscr) { /* hardware linked list transfer */ @@ -419,29 +422,31 @@ static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie) return -ETIMEDOUT; /* for the first descriptor we can be more accurate */ - if (desc_first->lli.dscr == dscr) - return atc_calc_bytes_left(ret, ctrla); + if (desc_first->lli.dscr == dscr) { + *residue = atc_calc_bytes_left(len, ctrla); + return 0; + } - ret -= desc_first->len; + len -= desc_first->len; list_for_each_entry(desc, &desc_first->tx_list, desc_node) { if (desc->lli.dscr == dscr) break; - ret -= desc->len; + len -= desc->len; } /* * For the current descriptor in the chain we can calculate * the remaining bytes using the channel's register. */ - ret = atc_calc_bytes_left(ret, ctrla); + *residue = atc_calc_bytes_left(len, ctrla); } else { /* single transfer */ ctrla = channel_readl(atchan, CTRLA); - ret = atc_calc_bytes_left(ret, ctrla); + *residue = atc_calc_bytes_left(len, ctrla); } - return ret; + return 0; } /** @@ -1457,31 +1462,32 @@ atc_tx_status(struct dma_chan *chan, { struct at_dma_chan *atchan = to_at_dma_chan(chan); unsigned long flags; - enum dma_status ret; - int bytes = 0; + enum dma_status dma_status; + u32 residue; + int ret; - ret = dma_cookie_status(chan, cookie, txstate); - if (ret == DMA_COMPLETE || !txstate) - return ret; + dma_status = dma_cookie_status(chan, cookie, txstate); + if (dma_status == DMA_COMPLETE || !txstate) + return dma_status; spin_lock_irqsave(&atchan->lock, flags); /* Get number of bytes left in the active transactions */ - bytes = atc_get_bytes_left(chan, cookie); + ret = atc_get_bytes_left(chan, cookie, &residue); spin_unlock_irqrestore(&atchan->lock, flags); - if (unlikely(bytes < 0)) { + if (unlikely(ret < 0)) { dev_vdbg(chan2dev(chan), "get residual bytes error\n"); return DMA_ERROR; } else { - dma_set_residue(txstate, bytes); + dma_set_residue(txstate, residue); } - dev_vdbg(chan2dev(chan), "tx_status %d: cookie = %d residue = %d\n", - ret, cookie, bytes); + dev_vdbg(chan2dev(chan), "tx_status %d: cookie = %d residue = %u\n", + dma_status, cookie, residue); - return ret; + return dma_status; } /**