From patchwork Tue Jun 16 00:09:28 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Robin Murphy X-Patchwork-Id: 11606049 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B047D913 for ; Tue, 16 Jun 2020 00:10:25 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4680E20739 for ; Tue, 16 Jun 2020 00:10:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="fHb/y0jr" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4680E20739 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=7cuhTPipBFBO3gZdCt15G1xIXf1FKVvcigI80lxU4zU=; b=fHb/y0jrvuM4F0 SmvEqAFaGVSQuFWM/MYjpftU+90q+BkipMIbrDjlfFJQRI/iXVU0Bw1HE7H2uRzMAib2yJXTeHuB6 qlOquEAE1WiMV9TnVHYljeCtB5sgMN5Hjo4KlH4YI1PrYeOAgn3X7PaX0TsG6uL65XvDhrVq7qiPE Yd2VlRrxLpTe9BAs6EJ+284lrFDluZJJ9zm8n99MXJ9ztzjA3hUoBSYARpSds0Hsv+YXl9DdmXBx7 zcYeM15mLjWfHE78d2pkW+evjW+QUbVj7FX21PqDov8ux2MZok2MJ7Z9PaR/JB8xN3Loe9IBAzyTH kUgS9HaMzjJMhJ//cw8g==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jkzBA-0001Ea-23; Tue, 16 Jun 2020 00:10:16 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jkzAc-0000Iu-Fh; Tue, 16 Jun 2020 00:09:43 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0D9A91042; Mon, 15 Jun 2020 17:09:42 -0700 (PDT) Received: from e121345-lin.cambridge.arm.com (e121345-lin.cambridge.arm.com [10.1.196.37]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 794253F73C; Mon, 15 Jun 2020 17:09:40 -0700 (PDT) From: Robin Murphy To: broonie@kernel.org, nsaenzjulienne@suse.de, f.fainelli@gmail.com, rjui@broadcom.com, sbranden@broadcom.com Subject: [PATCH 2/3] spi: bcm2835: Micro-optimise IRQ handler Date: Tue, 16 Jun 2020 01:09:28 +0100 Message-Id: <6b401cb521539caffab21f05b4c8cba6c9d27c6e.1592261248.git.robin.murphy@arm.com> X-Mailer: git-send-email 2.23.0.dirty In-Reply-To: References: MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200615_170942_592377_9791B57B X-CRM114-Status: GOOD ( 14.06 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.4 on bombadil.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [217.140.110.172 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, lukas@wunner.de, bcm-kernel-feedback-list@broadcom.com, linux-rpi-kernel@lists.infradead.org, kernel@martin.sperl.org, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org The IRQ handler only needs the struct spi_controller for the sake of the completion at the end of a transfer. Passing the struct bcm2835_spi directly as the IRQ data allows that level of indirection to be pushed into the completion path for the reverse lookup, and avoided entirely in all other cases. This saves one explicit load in the critical path, plus (for a GCC 8.3 build) two registers worth of stack frame overhead. Signed-off-by: Robin Murphy --- drivers/spi/spi-bcm2835.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index 524a91e52111..aec70ac8911e 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -86,6 +86,7 @@ MODULE_PARM_DESC(polling_limit_us, * @clk: core clock, divided to calculate serial clock * @irq: interrupt, signals TX FIFO empty or RX FIFO ¾ full * @tfr: SPI transfer currently processed + * @ctlr: SPI controller reverse lookup * @tx_buf: pointer whence next transmitted byte is read * @rx_buf: pointer where next received byte is written * @tx_len: remaining bytes to transmit @@ -125,6 +126,7 @@ struct bcm2835_spi { struct clk *clk; int irq; struct spi_transfer *tfr; + struct spi_controller *ctlr; const u8 *tx_buf; u8 *rx_buf; int tx_len; @@ -362,8 +364,7 @@ static void bcm2835_spi_reset_hw(struct bcm2835_spi *bs) static irqreturn_t bcm2835_spi_interrupt(int irq, void *dev_id) { - struct spi_controller *ctlr = dev_id; - struct bcm2835_spi *bs = spi_controller_get_devdata(ctlr); + struct bcm2835_spi *bs = dev_id; u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS); /* @@ -387,7 +388,7 @@ static irqreturn_t bcm2835_spi_interrupt(int irq, void *dev_id) /* Transfer complete - reset SPI HW */ bcm2835_spi_reset_hw(bs); /* wake up the framework */ - complete(&ctlr->xfer_completion); + complete(&bs->ctlr->xfer_completion); } return IRQ_HANDLED; @@ -1310,6 +1311,7 @@ static int bcm2835_spi_probe(struct platform_device *pdev) ctlr->dev.of_node = pdev->dev.of_node; bs = spi_controller_get_devdata(ctlr); + bs->ctlr = ctlr; bs->regs = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(bs->regs)) { @@ -1344,7 +1346,7 @@ static int bcm2835_spi_probe(struct platform_device *pdev) BCM2835_SPI_CS_CLEAR_RX | BCM2835_SPI_CS_CLEAR_TX); err = devm_request_irq(&pdev->dev, bs->irq, bcm2835_spi_interrupt, 0, - dev_name(&pdev->dev), ctlr); + dev_name(&pdev->dev), bs); if (err) { dev_err(&pdev->dev, "could not request IRQ: %d\n", err); goto out_dma_release;