From nobody Sun Apr 12 15:08:00 2026 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 BC5B9C4332F for ; Fri, 23 Dec 2022 13:42:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236157AbiLWNmU (ORCPT ); Fri, 23 Dec 2022 08:42:20 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46706 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236158AbiLWNmP (ORCPT ); Fri, 23 Dec 2022 08:42:15 -0500 X-Greylist: delayed 1809 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Fri, 23 Dec 2022 05:42:11 PST Received: from mail.pr-group.ru (mail.pr-group.ru [178.18.215.3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 96D0D379FF for ; Fri, 23 Dec 2022 05:42:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=metrotek.ru; s=mail; h=from:subject:date:message-id:to:cc:mime-version:content-transfer-encoding; bh=5rs080jU8HOw9fPaCutZbAKtsnfyAAH3tzJFpui62Dc=; b=UFtJvJZEOlCEnuSqv97FMOfNpS5wYTP6MpXfTiS36lTZCRIUasYVe5cE0Jmh+D0gm7PJ04F71zal6 xvhftxMdto1aMOdF6Hf1bcbDMys28woZYVJZGb+vAH2mJEWI+YYC5uUJC0+CreFLFhtWAUBgvmNVNl AzRvBkajVe5mTUtAiXCEnsYaiYcj0ogqk8P5PGbuOoYKEkFWhKSs4zKpX2anMAulNOTUukSATuOK77 85HB+q5zxHSEkAdMAkztUhqYVnzsCA8KgXBai24Pvmo1P9iWZr1VBNjOvU/4i3Xx5WUtejnzulsgvz v0SWdkDS04WxefszZDGsMt/eQ1q3Dfg== X-Kerio-Anti-Spam: Build: [Engines: 2.16.5.1460, Stamp: 3], Multi: [Enabled, t: (0.000010,0.035879)], BW: [Enabled, t: (0.000024,0.000002)], RTDA: [Enabled, t: (0.084619), Hit: No, Details: v2.42.0; Id: 15.52k09k.1gkvg1aha.iadb; mclb], total: 0(700) X-Footer: bWV0cm90ZWsucnU= Received: from localhost.localdomain ([78.37.162.181]) (authenticated user i.bornyakov@metrotek.ru) by mail.pr-group.ru with ESMTPSA (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256 bits)); Fri, 23 Dec 2022 15:41:23 +0300 From: Ivan Bornyakov To: linux-fpga@vger.kernel.org Cc: conor.dooley@microchip.com, mdf@kernel.org, hao.wu@intel.com, yilun.xu@intel.com, trix@redhat.com, linux-kernel@vger.kernel.org, system@metrotek.ru, Ivan Bornyakov Subject: [PATCH] fpga: microchip-spi: move SPI I/O buffers out of stack Date: Fri, 23 Dec 2022 15:38:54 +0300 Message-Id: <20221223123854.8023-1-i.bornyakov@metrotek.ru> X-Mailer: git-send-email 2.38.2 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" As spi-summary doc says: > I/O buffers use the usual Linux rules, and must be DMA-safe. > You'd normally allocate them from the heap or free page pool. > Don't use the stack, or anything that's declared "static". Replace spi_write() with spi_write_then_read(), which is dma-safe for on-stack buffers. Use allocated buffers for transfers used in spi_sync_transfer(). Although everything works OK with stack-located I/O buffers, better follow the doc to be safe. While at it, replace busy loop in mpf_poll_status() routine with read_poll_timeout() macro. Original busy loop is not too reliable, as it takes different times on different systems. Fixes: 5f8d4a900830 ("fpga: microchip-spi: add Microchip MPF FPGA manager") Signed-off-by: Ivan Bornyakov --- drivers/fpga/microchip-spi.c | 145 +++++++++++++++++++---------------- 1 file changed, 80 insertions(+), 65 deletions(-) diff --git a/drivers/fpga/microchip-spi.c b/drivers/fpga/microchip-spi.c index 7436976ea904..dfb4e071db86 100644 --- a/drivers/fpga/microchip-spi.c +++ b/drivers/fpga/microchip-spi.c @@ -6,6 +6,7 @@ #include #include #include +#include #include #include #include @@ -33,7 +34,6 @@ =20 #define MPF_BITS_PER_COMPONENT_SIZE 22 =20 -#define MPF_STATUS_POLL_RETRIES 10000 #define MPF_STATUS_BUSY BIT(0) #define MPF_STATUS_READY BIT(1) #define MPF_STATUS_SPI_VIOLATION BIT(2) @@ -42,46 +42,55 @@ struct mpf_priv { struct spi_device *spi; bool program_mode; + u8 *tx; + u8 *rx; }; =20 -static int mpf_read_status(struct spi_device *spi) +static int mpf_read_status(struct mpf_priv *priv) { - u8 status =3D 0, status_command =3D MPF_SPI_READ_STATUS; - struct spi_transfer xfers[2] =3D { 0 }; - int ret; - /* * HW status is returned on MISO in the first byte after CS went * active. However, first reading can be inadequate, so we submit * two identical SPI transfers and use result of the later one. */ - xfers[0].tx_buf =3D &status_command; - xfers[1].tx_buf =3D &status_command; - xfers[0].rx_buf =3D &status; - xfers[1].rx_buf =3D &status; - xfers[0].len =3D 1; - xfers[1].len =3D 1; - xfers[0].cs_change =3D 1; + struct spi_transfer xfers[2] =3D { + { + .tx_buf =3D priv->tx, + .rx_buf =3D priv->rx, + .len =3D 1, + .cs_change =3D 1, + }, { + .tx_buf =3D priv->tx, + .rx_buf =3D priv->rx, + .len =3D 1, + }, + }; + u8 status; + int ret; =20 - ret =3D spi_sync_transfer(spi, xfers, 2); + *priv->tx =3D MPF_SPI_READ_STATUS; + + ret =3D spi_sync_transfer(priv->spi, xfers, 2); + if (ret) + return ret; + + status =3D *priv->rx; =20 if ((status & MPF_STATUS_SPI_VIOLATION) || (status & MPF_STATUS_SPI_ERROR)) - ret =3D -EIO; + return -EIO; =20 - return ret ? : status; + return status; } =20 static enum fpga_mgr_states mpf_ops_state(struct fpga_manager *mgr) { struct mpf_priv *priv =3D mgr->priv; - struct spi_device *spi; bool program_mode; int status; =20 - spi =3D priv->spi; program_mode =3D priv->program_mode; - status =3D mpf_read_status(spi); + status =3D mpf_read_status(priv); =20 if (!program_mode && !status) return FPGA_MGR_STATE_OPERATING; @@ -186,51 +195,47 @@ static int mpf_ops_parse_header(struct fpga_manager *= mgr, } =20 /* Poll HW status until busy bit is cleared and mask bits are set. */ -static int mpf_poll_status(struct spi_device *spi, u8 mask) +static int mpf_poll_status(struct mpf_priv *priv, u8 mask) { - int status, retries =3D MPF_STATUS_POLL_RETRIES; - - while (retries--) { - status =3D mpf_read_status(spi); - if (status < 0) - return status; + int ret, status; =20 - if (status & MPF_STATUS_BUSY) - continue; - - if (!mask || (status & mask)) - return status; - } + ret =3D read_poll_timeout(mpf_read_status, status, + (status < 0) || + (!(status & MPF_STATUS_BUSY) && + (!mask || (status & mask))), + 0, 2 * USEC_PER_SEC, false, priv); + if (ret < 0) + return ret; =20 - return -EBUSY; + return status; } =20 -static int mpf_spi_write(struct spi_device *spi, const void *buf, size_t b= uf_size) +static int mpf_spi_write(struct mpf_priv *priv, const void *buf, size_t bu= f_size) { - int status =3D mpf_poll_status(spi, 0); + int status =3D mpf_poll_status(priv, 0); =20 if (status < 0) return status; =20 - return spi_write(spi, buf, buf_size); + return spi_write_then_read(priv->spi, buf, buf_size, NULL, 0); } =20 -static int mpf_spi_write_then_read(struct spi_device *spi, +static int mpf_spi_write_then_read(struct mpf_priv *priv, const void *txbuf, size_t txbuf_size, void *rxbuf, size_t rxbuf_size) { const u8 read_command[] =3D { MPF_SPI_READ_DATA }; int ret; =20 - ret =3D mpf_spi_write(spi, txbuf, txbuf_size); + ret =3D mpf_spi_write(priv, txbuf, txbuf_size); if (ret) return ret; =20 - ret =3D mpf_poll_status(spi, MPF_STATUS_READY); + ret =3D mpf_poll_status(priv, MPF_STATUS_READY); if (ret < 0) return ret; =20 - return spi_write_then_read(spi, read_command, sizeof(read_command), + return spi_write_then_read(priv->spi, read_command, sizeof(read_command), rxbuf, rxbuf_size); } =20 @@ -242,7 +247,6 @@ static int mpf_ops_write_init(struct fpga_manager *mgr, const u8 isc_en_command[] =3D { MPF_SPI_ISC_ENABLE }; struct mpf_priv *priv =3D mgr->priv; struct device *dev =3D &mgr->dev; - struct spi_device *spi; u32 isc_ret =3D 0; int ret; =20 @@ -251,9 +255,7 @@ static int mpf_ops_write_init(struct fpga_manager *mgr, return -EOPNOTSUPP; } =20 - spi =3D priv->spi; - - ret =3D mpf_spi_write_then_read(spi, isc_en_command, sizeof(isc_en_comman= d), + ret =3D mpf_spi_write_then_read(priv, isc_en_command, sizeof(isc_en_comma= nd), &isc_ret, sizeof(isc_ret)); if (ret || isc_ret) { dev_err(dev, "Failed to enable ISC: spi_ret %d, isc_ret %u\n", @@ -261,7 +263,7 @@ static int mpf_ops_write_init(struct fpga_manager *mgr, return -EFAULT; } =20 - ret =3D mpf_spi_write(spi, program_mode, sizeof(program_mode)); + ret =3D mpf_spi_write(priv, program_mode, sizeof(program_mode)); if (ret) { dev_err(dev, "Failed to enter program mode: %d\n", ret); return ret; @@ -272,13 +274,32 @@ static int mpf_ops_write_init(struct fpga_manager *mg= r, return 0; } =20 +static int mpf_spi_frame_write(struct mpf_priv *priv, const char *buf) +{ + struct spi_transfer xfers[2] =3D { + { + .tx_buf =3D priv->tx, + .len =3D 1, + }, { + .tx_buf =3D buf, + .len =3D MPF_SPI_FRAME_SIZE, + }, + }; + int ret; + + ret =3D mpf_poll_status(priv, 0); + if (ret < 0) + return ret; + + *priv->tx =3D MPF_SPI_FRAME; + + return spi_sync_transfer(priv->spi, xfers, ARRAY_SIZE(xfers)); +} + static int mpf_ops_write(struct fpga_manager *mgr, const char *buf, size_t= count) { - u8 spi_frame_command[] =3D { MPF_SPI_FRAME }; - struct spi_transfer xfers[2] =3D { 0 }; struct mpf_priv *priv =3D mgr->priv; struct device *dev =3D &mgr->dev; - struct spi_device *spi; int ret, i; =20 if (count % MPF_SPI_FRAME_SIZE) { @@ -287,19 +308,8 @@ static int mpf_ops_write(struct fpga_manager *mgr, con= st char *buf, size_t count return -EINVAL; } =20 - spi =3D priv->spi; - - xfers[0].tx_buf =3D spi_frame_command; - xfers[0].len =3D sizeof(spi_frame_command); - for (i =3D 0; i < count / MPF_SPI_FRAME_SIZE; i++) { - xfers[1].tx_buf =3D buf + i * MPF_SPI_FRAME_SIZE; - xfers[1].len =3D MPF_SPI_FRAME_SIZE; - - ret =3D mpf_poll_status(spi, 0); - if (ret >=3D 0) - ret =3D spi_sync_transfer(spi, xfers, ARRAY_SIZE(xfers)); - + ret =3D mpf_spi_frame_write(priv, buf + i * MPF_SPI_FRAME_SIZE); if (ret) { dev_err(dev, "Failed to write bitstream frame %d/%zu\n", i, count / MPF_SPI_FRAME_SIZE); @@ -317,12 +327,9 @@ static int mpf_ops_write_complete(struct fpga_manager = *mgr, const u8 release_command[] =3D { MPF_SPI_RELEASE }; struct mpf_priv *priv =3D mgr->priv; struct device *dev =3D &mgr->dev; - struct spi_device *spi; int ret; =20 - spi =3D priv->spi; - - ret =3D mpf_spi_write(spi, isc_dis_command, sizeof(isc_dis_command)); + ret =3D mpf_spi_write(priv, isc_dis_command, sizeof(isc_dis_command)); if (ret) { dev_err(dev, "Failed to disable ISC: %d\n", ret); return ret; @@ -330,7 +337,7 @@ static int mpf_ops_write_complete(struct fpga_manager *= mgr, =20 usleep_range(1000, 2000); =20 - ret =3D mpf_spi_write(spi, release_command, sizeof(release_command)); + ret =3D mpf_spi_write(priv, release_command, sizeof(release_command)); if (ret) { dev_err(dev, "Failed to exit program mode: %d\n", ret); return ret; @@ -361,6 +368,14 @@ static int mpf_probe(struct spi_device *spi) if (!priv) return -ENOMEM; =20 + priv->tx =3D devm_kmalloc(dev, 1, GFP_KERNEL); + if (!priv->tx) + return -ENOMEM; + + priv->rx =3D devm_kmalloc(dev, 1, GFP_KERNEL); + if (!priv->rx) + return -ENOMEM; + priv->spi =3D spi; =20 mgr =3D devm_fpga_mgr_register(dev, "Microchip Polarfire SPI FPGA Manager= ", --=20 2.38.2