From patchwork Sun Feb 24 16:23:09 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Sperl X-Patchwork-Id: 10828023 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2F5F013B5 for ; Sun, 24 Feb 2019 16:23:22 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1B9F12B08F for ; Sun, 24 Feb 2019 16:23:22 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0E2ED2B094; Sun, 24 Feb 2019 16:23:22 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 49CB62B08F for ; Sun, 24 Feb 2019 16:23:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728543AbfBXQXU (ORCPT ); Sun, 24 Feb 2019 11:23:20 -0500 Received: from 212-186-180-163.static.upcbusiness.at ([212.186.180.163]:48058 "EHLO cgate.sperl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727752AbfBXQXU (ORCPT ); Sun, 24 Feb 2019 11:23:20 -0500 Received: from hc1.intern.sperl.org (account martin@sperl.org [10.10.10.59] verified) by sperl.org (CommuniGate Pro SMTP 6.2.1 _community_) with ESMTPSA id 7757580; Sun, 24 Feb 2019 16:23:15 +0000 From: kernel@martin.sperl.org To: Mark Brown , Eric Anholt , Stefan Wahren , linux-spi@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org Cc: Martin Sperl Subject: [PATCH 1/3] spi: bcm2835: add driver stats to debugfs Date: Sun, 24 Feb 2019 16:23:09 +0000 Message-Id: <20190224162311.23899-1-kernel@martin.sperl.org> X-Mailer: git-send-email 2.11.0 Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Martin Sperl To estimate efficiency add statistics on transfer types (polling, interrupt and dma) used to debugfs. Signed-off-by: Martin Sperl --- drivers/spi/spi-bcm2835.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) -- 2.11.0 diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index c2912c1e09c5..0ccc6a2733c6 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -22,6 +22,7 @@ #include #include +#include #include #include #include @@ -111,8 +112,60 @@ struct bcm2835_spi { int rx_prologue; unsigned int tx_spillover; unsigned int dma_pending; + +#if defined(CONFIG_DEBUG_FS) +#define BCM2835_AUX_INCR(field) ((field)++) + u64 count_transfer_polling; + u64 count_transfer_irq; + u64 count_transfer_irq_after_poll; + u64 count_transfer_dma; + + struct dentry *debugfs_dir; +#else +#define BCM2835_AUX_INCR(field) +#endif /* CONFIG_DEBUG_FS */ }; +#if defined(CONFIG_DEBUG_FS) +static void bcm2835_debugfs_create(struct bcm2835_spi *bs, + const char *dname) +{ + char name[64]; + struct dentry *dir; + + /* get full name */ + snprintf(name, sizeof(name), "spi-bcm2835-%s", dname); + + /* the base directory */ + dir = debugfs_create_dir(name, NULL); + bs->debugfs_dir = dir; + + /* the counters */ + debugfs_create_u64("count_transfer_polling", 0444, dir, + &bs->count_transfer_polling); + debugfs_create_u64("count_transfer_irq", 0444, dir, + &bs->count_transfer_irq); + debugfs_create_u64("count_transfer_irq_after_poll", 0444, dir, + &bs->count_transfer_irq_after_poll); + debugfs_create_u64("count_transfer_dma", 0444, dir, + &bs->count_transfer_dma); +} + +static void bcm2835_debugfs_remove(struct bcm2835_spi *bs) +{ + debugfs_remove_recursive(bs->debugfs_dir); + bs->debugfs_dir = NULL; +} +#else +static void bcm2835_debugfs_create(struct bcm2835_spi *bs) +{ +} + +static void bcm2835_debugfs_remove(struct bcm2835_spi *bs) +{ +} +#endif /* CONFIG_DEBUG_FS */ + static inline u32 bcm2835_rd(struct bcm2835_spi *bs, unsigned reg) { return readl(bs->regs + reg); @@ -316,6 +369,9 @@ static int bcm2835_spi_transfer_one_irq(struct spi_master *master, { struct bcm2835_spi *bs = spi_master_get_devdata(master); + /* update statistics */ + BCM2835_AUX_INCR(bs->count_transfer_irq); + /* * Enable HW block, but with interrupts still disabled. * Otherwise the empty TX FIFO would immediately trigger an interrupt. @@ -574,6 +630,9 @@ static int bcm2835_spi_transfer_one_dma(struct spi_master *master, struct bcm2835_spi *bs = spi_master_get_devdata(master); int ret; + /* update statistics */ + BCM2835_AUX_INCR(bs->count_transfer_dma); + /* * Transfer first few bytes without DMA if length of first TX or RX * sglist entry is not a multiple of 4 bytes (hardware limitation). @@ -731,6 +790,9 @@ static int bcm2835_spi_transfer_one_poll(struct spi_master *master, struct bcm2835_spi *bs = spi_master_get_devdata(master); unsigned long timeout; + /* update statistics */ + BCM2835_AUX_INCR(bs->count_transfer_polling); + /* enable HW block without interrupts */ bcm2835_wr(bs, BCM2835_SPI_CS, cs | BCM2835_SPI_CS_TA); @@ -759,6 +821,8 @@ static int bcm2835_spi_transfer_one_poll(struct spi_master *master, "timeout period reached: jiffies: %lu remaining tx/rx: %d/%d - falling back to interrupt mode\n", jiffies - timeout, bs->tx_len, bs->rx_len); + /* update statistics */ + BCM2835_AUX_INCR(bs->count_transfer_irq_after_poll); /* fall back to interrupt mode */ return bcm2835_spi_transfer_one_irq(master, spi, tfr, cs, false); @@ -991,6 +1055,8 @@ static int bcm2835_spi_probe(struct platform_device *pdev) goto out_clk_disable; } + bcm2835_debugfs_create(bs, dev_name(&pdev->dev)); + return 0; out_clk_disable: @@ -1005,6 +1071,8 @@ static int bcm2835_spi_remove(struct platform_device *pdev) struct spi_master *master = platform_get_drvdata(pdev); struct bcm2835_spi *bs = spi_master_get_devdata(master); + bcm2835_debugfs_remove(bs); + /* Clear FIFOs, and disable the HW block */ bcm2835_wr(bs, BCM2835_SPI_CS, BCM2835_SPI_CS_CLEAR_RX | BCM2835_SPI_CS_CLEAR_TX); From patchwork Sun Feb 24 16:23:10 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Sperl X-Patchwork-Id: 10828025 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C2F46180E for ; Sun, 24 Feb 2019 16:23:22 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AF0CA2B08F for ; Sun, 24 Feb 2019 16:23:22 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A35E32B094; Sun, 24 Feb 2019 16:23:22 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3C9C52B08F for ; Sun, 24 Feb 2019 16:23:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727752AbfBXQXW (ORCPT ); Sun, 24 Feb 2019 11:23:22 -0500 Received: from 212-186-180-163.static.upcbusiness.at ([212.186.180.163]:48058 "EHLO cgate.sperl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728540AbfBXQXV (ORCPT ); Sun, 24 Feb 2019 11:23:21 -0500 Received: from hc1.intern.sperl.org (account martin@sperl.org [10.10.10.59] verified) by sperl.org (CommuniGate Pro SMTP 6.2.1 _community_) with ESMTPSA id 7757584; Sun, 24 Feb 2019 16:23:15 +0000 From: kernel@martin.sperl.org To: Mark Brown , Eric Anholt , Stefan Wahren , linux-spi@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org Cc: Martin Sperl Subject: [PATCH 2/3] spi: bcm2835: avoid 64 bit arithmetic and allow to configure polling limit Date: Sun, 24 Feb 2019 16:23:10 +0000 Message-Id: <20190224162311.23899-2-kernel@martin.sperl.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190224162311.23899-1-kernel@martin.sperl.org> References: <20190224162311.23899-1-kernel@martin.sperl.org> Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Martin Sperl In analogy to commit d704afffe65c ("spi: bcm2835aux: Avoid 64-bit arithmetic in xfer len calc") avoid 64 bit calculations and make the polling interval configurable as a module parameter. Signed-off-by: Martin Sperl --- Note this patch requires the effective_speed_hz patch to be included --- drivers/spi/spi-bcm2835.c | 36 ++++++++++++++++++++---------------- 1 file changed, 20 insertions(+), 16 deletions(-) -- 2.11.0 diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index 0ccc6a2733c6..dcf922ca2603 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -38,6 +38,12 @@ #include #include +/* define polling limits */ +unsigned int polling_limit_us = 30; +module_param(polling_limit_us, uint, 0664); +MODULE_PARM_DESC(polling_limit_us, + "time in us to run a transfer in polling mode\n"); + /* SPI register offsets */ #define BCM2835_SPI_CS 0x00 #define BCM2835_SPI_FIFO 0x04 @@ -74,8 +80,6 @@ #define BCM2835_SPI_FIFO_SIZE 64 #define BCM2835_SPI_FIFO_SIZE_3_4 48 -#define BCM2835_SPI_POLLING_LIMIT_US 30 -#define BCM2835_SPI_POLLING_JIFFIES 2 #define BCM2835_SPI_DMA_MIN_LENGTH 96 #define BCM2835_SPI_MODE_BITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH \ | SPI_NO_CS | SPI_3WIRE) @@ -784,8 +788,7 @@ static void bcm2835_dma_init(struct spi_master *master, struct device *dev) static int bcm2835_spi_transfer_one_poll(struct spi_master *master, struct spi_device *spi, struct spi_transfer *tfr, - u32 cs, - unsigned long long xfer_time_us) + u32 cs) { struct bcm2835_spi *bs = spi_master_get_devdata(master); unsigned long timeout; @@ -802,8 +805,8 @@ static int bcm2835_spi_transfer_one_poll(struct spi_master *master, */ bcm2835_wr_fifo_blind(bs, BCM2835_SPI_FIFO_SIZE); - /* set the timeout */ - timeout = jiffies + BCM2835_SPI_POLLING_JIFFIES; + /* set the timeout to at least 2 jiffies */ + timeout = jiffies + 2 + HZ * polling_limit_us / 1000000; /* loop until finished the transfer */ while (bs->rx_len) { @@ -840,8 +843,7 @@ static int bcm2835_spi_transfer_one(struct spi_master *master, struct spi_transfer *tfr) { struct bcm2835_spi *bs = spi_master_get_devdata(master); - unsigned long spi_hz, clk_hz, cdiv; - unsigned long long xfer_time_us; + unsigned long spi_hz, clk_hz, cdiv, hz_per_byte, byte_limit; u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS); /* set clock */ @@ -882,16 +884,18 @@ static int bcm2835_spi_transfer_one(struct spi_master *master, bs->tx_len = tfr->len; bs->rx_len = tfr->len; - /* calculate the estimated time in us the transfer runs */ - xfer_time_us = (unsigned long long)tfr->len - * 9 /* clocks/byte - SPI-HW waits 1 clock after each byte */ - * 1000000; - do_div(xfer_time_us, tfr->effective_speed_hz); + /* Calculate the estimated time in us the transfer runs. Note that + * there is 1 idle clocks cycles after each byte transferredo - so + * 9 cycles/byte. This is used to find the number + * of Hz per byte per polling limit. E.g., we can transfer 1 byte in + * 30 us per 300,000 Hz of bus clock. + */ + hz_per_byte = polling_limit_us ? (9 * 1000000) / polling_limit_us : 0; + byte_limit = hz_per_byte ? tfr->effective_speed_hz / hz_per_byte : 1; /* for short requests run polling*/ - if (xfer_time_us <= BCM2835_SPI_POLLING_LIMIT_US) - return bcm2835_spi_transfer_one_poll(master, spi, tfr, - cs, xfer_time_us); + if (tfr->len < byte_limit) + return bcm2835_spi_transfer_one_poll(master, spi, tfr, cs); /* run in dma mode if conditions are right */ if (master->can_dma && bcm2835_spi_can_dma(master, spi, tfr)) From patchwork Sun Feb 24 16:23:11 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Sperl X-Patchwork-Id: 10828027 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E575215AC for ; Sun, 24 Feb 2019 16:23:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D27752B08F for ; Sun, 24 Feb 2019 16:23:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C6CD32B094; Sun, 24 Feb 2019 16:23:23 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 65A692B08F for ; Sun, 24 Feb 2019 16:23:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728544AbfBXQXX (ORCPT ); Sun, 24 Feb 2019 11:23:23 -0500 Received: from 212-186-180-163.static.upcbusiness.at ([212.186.180.163]:48058 "EHLO cgate.sperl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728470AbfBXQXX (ORCPT ); Sun, 24 Feb 2019 11:23:23 -0500 Received: from hc1.intern.sperl.org (account martin@sperl.org [10.10.10.59] verified) by sperl.org (CommuniGate Pro SMTP 6.2.1 _community_) with ESMTPSA id 7757585; Sun, 24 Feb 2019 16:23:15 +0000 From: kernel@martin.sperl.org To: Mark Brown , Eric Anholt , Stefan Wahren , linux-spi@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org Cc: Martin Sperl Subject: [PATCH 3/3] spi: bcm2835: add module parameter to configure minimum length for dma Date: Sun, 24 Feb 2019 16:23:11 +0000 Message-Id: <20190224162311.23899-3-kernel@martin.sperl.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190224162311.23899-1-kernel@martin.sperl.org> References: <20190224162311.23899-1-kernel@martin.sperl.org> Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Martin Sperl Allow setting the length of the transfer at which dma is used by setting a module parameter. Signed-off-by: Martin Sperl --- drivers/spi/spi-bcm2835.c | 40 +++++++++++++++++++++++++++++++++++++--- 1 file changed, 37 insertions(+), 3 deletions(-) -- 2.11.0 diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index dcf922ca2603..ef4b3468a97d 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include #include @@ -44,6 +45,39 @@ module_param(polling_limit_us, uint, 0664); MODULE_PARM_DESC(polling_limit_us, "time in us to run a transfer in polling mode\n"); +/* define dma min number of bytes to use in dma mode with value validation */ +static int dma_min_bytes_limit_set(const char *val, + const struct kernel_param *kp) +{ + unsigned int v; + + if (kstrtouint(val, 10, &v)) + return -EINVAL; + /* value needs to be a multiple of 4 */ + if (v % 4) { + pr_err("dma_min_bytes_limit needs to be a multiple of 4\n"); + return -EINVAL; + } + /* value needs to be at least 6 - so actually 8 - rational below */ + if (v < 6) { + pr_err("dma_min_bytes_limit needs to be at least 8\n"); + return -EINVAL; + } + + return param_set_uint(val, kp); +} + +static const struct kernel_param_ops dma_min_bytes_limit_ops = { + .set = dma_min_bytes_limit_set, + .get = param_get_int, +}; + +unsigned int dma_min_bytes_limit = 96; +module_param_cb(dma_min_bytes_limit, &dma_min_bytes_limit_ops, + &dma_min_bytes_limit, 0664); +MODULE_PARM_DESC(dma_min_bytes_limit, + "minimum number of bytes to run a transfer in dma mode\n"); + /* SPI register offsets */ #define BCM2835_SPI_CS 0x00 #define BCM2835_SPI_FIFO 0x04 @@ -80,7 +114,6 @@ MODULE_PARM_DESC(polling_limit_us, #define BCM2835_SPI_FIFO_SIZE 64 #define BCM2835_SPI_FIFO_SIZE_3_4 48 -#define BCM2835_SPI_DMA_MIN_LENGTH 96 #define BCM2835_SPI_MODE_BITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH \ | SPI_NO_CS | SPI_3WIRE) @@ -447,7 +480,8 @@ static int bcm2835_spi_transfer_one_irq(struct spi_master *master, * if the length of the first is *exactly* 1. * * At most 6 bytes are written and at most 3 bytes read. Do we know the - * transfer has this many bytes? Yes, see BCM2835_SPI_DMA_MIN_LENGTH. + * transfer has this many bytes? Yes, see validation in + * dma_min_bytes_limit_set. * * The FIFO is normally accessed with 8-bit width by the CPU and 32-bit width * by the DMA engine. Toggling the DMA Enable flag in the CS register switches @@ -690,7 +724,7 @@ static bool bcm2835_spi_can_dma(struct spi_master *master, struct spi_transfer *tfr) { /* we start DMA efforts only on bigger transfers */ - if (tfr->len < BCM2835_SPI_DMA_MIN_LENGTH) + if (tfr->len < dma_min_bytes_limit) return false; /* BCM2835_SPI_DLEN has defined a max transfer size as