From patchwork Thu May 20 21:16:57 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Oltean X-Patchwork-Id: 12271387 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 565B5C433B4 for ; Thu, 20 May 2021 21:17:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E67A61353 for ; Thu, 20 May 2021 21:17:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230049AbhETVS3 (ORCPT ); Thu, 20 May 2021 17:18:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35630 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229808AbhETVS2 (ORCPT ); Thu, 20 May 2021 17:18:28 -0400 Received: from mail-ej1-x635.google.com (mail-ej1-x635.google.com [IPv6:2a00:1450:4864:20::635]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A161EC061574; Thu, 20 May 2021 14:17:06 -0700 (PDT) Received: by mail-ej1-x635.google.com with SMTP id c20so27481837ejm.3; Thu, 20 May 2021 14:17:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=G6EnG++jASat6OrecSOupBpcUWQ9s4enAjVn4rOIlRU=; b=VKCxQuDQlrdwxlVipcVBgBpge+6Dbbj+Fl/IGktyapOJuk6q2dbdDCV4EW7HxnhhmA M69GnI0eOvYVf8ME3ivB+6R6moQc/XMh+IXoGBEm1soUK02kytxu8IsX4E+soJ2JzAsm /N0FJSwdWf3VZlCBd8xTEpaZFb7l2heVOdDRBB2aeKC/5jKXuCQywU2AEk3gBj7NgXoN hjCOKDSP8BaUfVixedNjHEZMHZTiYUO1hMElXInLhXBgA2vFFIAZtFP6WbKUonw48uUW LtINPYSvSuH1BHNBvZx2UO2QuYllL+jIOP6b0+o52KDsD7bv2b2UATt9BZa4CBvz52GA 21VQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=G6EnG++jASat6OrecSOupBpcUWQ9s4enAjVn4rOIlRU=; b=Xepa0tACCtZdgoNqzKgoLbGlyDFBW9QerLmjUsy6DUNwAJahcQRtr+3FjQDvLsLF7i sqo7b7H1u7MMwOtzsC75YwPv1nZahotYHDTwaPu7q79/QqjJZzWZDEE2OEP8BastuO8v 8/TKTfYM/cY3l5xx+AaOF2IyAYPCqC76Za+0BrZiOIH9OuzstgBC3QSu5Me4ZieMXxUd Eocx7jg6EC2WaUQZJCCKjHPhoY09DM+nzYQ/Je2skzmBVUUfgDO2JhR4zr0xhJjg37YA U95WTvGi+tXOfi5iKmFiMpYI4qi0LWFhYhUryVgZshctcehehN1rq9HzFscI/c2b8hAm 1WSA== X-Gm-Message-State: AOAM531s1lQPkvQWOAMwXuAwbcZj4xOi9vYf4I7jAvpwsxDpuoTDpRhj e1fLZ98l2BIPdF9LanbIGOg= X-Google-Smtp-Source: ABdhPJzrx9DL6WTHChMJ94W6cPt/AQ+4OrYhT2PEnQQkiCZWBfyrK+KOeka4Igz1n5UsVhGGe50+nA== X-Received: by 2002:a17:906:11cc:: with SMTP id o12mr6434216eja.547.1621545425267; Thu, 20 May 2021 14:17:05 -0700 (PDT) Received: from localhost.localdomain ([188.26.52.84]) by smtp.gmail.com with ESMTPSA id w10sm2084212ejq.48.2021.05.20.14.17.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 May 2021 14:17:05 -0700 (PDT) From: Vladimir Oltean To: Jakub Kicinski , "David S. Miller" , netdev@vger.kernel.org Cc: Florian Fainelli , Andrew Lunn , Vivien Didelot , Mark Brown , linux-spi@vger.kernel.org, Guenter Roeck , Vladimir Oltean Subject: [PATCH v3 net-next 2/2] net: dsa: sja1105: adapt to a SPI controller with a limited max transfer size Date: Fri, 21 May 2021 00:16:57 +0300 Message-Id: <20210520211657.3451036-3-olteanv@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210520211657.3451036-1-olteanv@gmail.com> References: <20210520211657.3451036-1-olteanv@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org From: Vladimir Oltean The static config of the sja1105 switch is a long stream of bytes which is programmed to the hardware in chunks (portions with the chip select continuously asserted) of max 256 bytes each. Each chunk is a spi_message composed of 2 spi_transfers: the buffer with the data and a preceding buffer with the SPI access header. Only that certain SPI controllers, such as the spi-sc18is602 I2C-to-SPI bridge, cannot keep the chip select asserted for that long. The spi_max_transfer_size() and spi_max_message_size() functions are how the controller can impose its hardware limitations upon the SPI peripheral driver. For the sja1105 driver to work with these controllers, both buffers must be smaller than the transfer limit, and their sum must be smaller than the message limit. Regression-tested on a switch connected to a controller with no limitations (spi-fsl-dspi) as well as with one with caps for both max_transfer_size and max_message_size (spi-sc18is602). Signed-off-by: Vladimir Oltean --- drivers/net/dsa/sja1105/sja1105.h | 1 + drivers/net/dsa/sja1105/sja1105_main.c | 28 +++++++++++++++++++ drivers/net/dsa/sja1105/sja1105_spi.c | 16 +++++------ .../net/dsa/sja1105/sja1105_static_config.h | 2 ++ 4 files changed, 38 insertions(+), 9 deletions(-) diff --git a/drivers/net/dsa/sja1105/sja1105.h b/drivers/net/dsa/sja1105/sja1105.h index f9e87fb33da0..7ec40c4b2d5a 100644 --- a/drivers/net/dsa/sja1105/sja1105.h +++ b/drivers/net/dsa/sja1105/sja1105.h @@ -209,6 +209,7 @@ struct sja1105_private { unsigned long ucast_egress_floods; unsigned long bcast_egress_floods; const struct sja1105_info *info; + size_t max_xfer_len; struct gpio_desc *reset_gpio; struct spi_device *spidev; struct dsa_switch *ds; diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c index 1d2d34d40f84..585142caa5b0 100644 --- a/drivers/net/dsa/sja1105/sja1105_main.c +++ b/drivers/net/dsa/sja1105/sja1105_main.c @@ -3563,6 +3563,7 @@ static int sja1105_probe(struct spi_device *spi) struct sja1105_tagger_data *tagger_data; struct device *dev = &spi->dev; struct sja1105_private *priv; + size_t max_xfer, max_msg; struct dsa_switch *ds; int rc, port; @@ -3596,6 +3597,33 @@ static int sja1105_probe(struct spi_device *spi) return rc; } + /* In sja1105_xfer, we send spi_messages composed of two spi_transfers: + * a small one for the message header and another one for the current + * chunk of the packed buffer. + * Check that the restrictions imposed by the SPI controller are + * respected: the chunk buffer is smaller than the max transfer size, + * and the total length of the chunk plus its message header is smaller + * than the max message size. + * We do that during probe time since the maximum transfer size is a + * runtime invariant. + */ + max_xfer = spi_max_transfer_size(spi); + max_msg = spi_max_message_size(spi); + + /* We need to send at least one 64-bit word of SPI payload per message + * in order to be able to make useful progress. + */ + if (max_msg < SJA1105_SIZE_SPI_MSG_HEADER + 8) { + dev_err(dev, "SPI master cannot send large enough buffers, aborting\n"); + return -EINVAL; + } + + priv->max_xfer_len = SJA1105_SIZE_SPI_MSG_MAXLEN; + if (priv->max_xfer_len > max_xfer) + priv->max_xfer_len = max_xfer; + if (priv->max_xfer_len > max_msg - SJA1105_SIZE_SPI_MSG_HEADER) + priv->max_xfer_len = max_msg - SJA1105_SIZE_SPI_MSG_HEADER; + priv->info = of_device_get_match_data(dev); /* Detect hardware device */ diff --git a/drivers/net/dsa/sja1105/sja1105_spi.c b/drivers/net/dsa/sja1105/sja1105_spi.c index 8746e3f158a0..5a7b404bf3ce 100644 --- a/drivers/net/dsa/sja1105/sja1105_spi.c +++ b/drivers/net/dsa/sja1105/sja1105_spi.c @@ -8,8 +8,6 @@ #include "sja1105.h" #define SJA1105_SIZE_RESET_CMD 4 -#define SJA1105_SIZE_SPI_MSG_HEADER 4 -#define SJA1105_SIZE_SPI_MSG_MAXLEN (64 * 4) struct sja1105_chunk { u8 *buf; @@ -40,19 +38,19 @@ static int sja1105_xfer(const struct sja1105_private *priv, size_t len, struct ptp_system_timestamp *ptp_sts) { u8 hdr_buf[SJA1105_SIZE_SPI_MSG_HEADER] = {0}; - struct sja1105_chunk chunk = { - .len = min_t(size_t, len, SJA1105_SIZE_SPI_MSG_MAXLEN), - .reg_addr = reg_addr, - .buf = buf, - }; struct spi_device *spi = priv->spidev; struct spi_transfer xfers[2] = {0}; struct spi_transfer *chunk_xfer; struct spi_transfer *hdr_xfer; + struct sja1105_chunk chunk; int num_chunks; int rc, i = 0; - num_chunks = DIV_ROUND_UP(len, SJA1105_SIZE_SPI_MSG_MAXLEN); + num_chunks = DIV_ROUND_UP(len, priv->max_xfer_len); + + chunk.reg_addr = reg_addr; + chunk.buf = buf; + chunk.len = min_t(size_t, len, priv->max_xfer_len); hdr_xfer = &xfers[0]; chunk_xfer = &xfers[1]; @@ -104,7 +102,7 @@ static int sja1105_xfer(const struct sja1105_private *priv, chunk.buf += chunk.len; chunk.reg_addr += chunk.len / 4; chunk.len = min_t(size_t, (ptrdiff_t)(buf + len - chunk.buf), - SJA1105_SIZE_SPI_MSG_MAXLEN); + priv->max_xfer_len); rc = spi_sync_transfer(spi, xfers, 2); if (rc < 0) { diff --git a/drivers/net/dsa/sja1105/sja1105_static_config.h b/drivers/net/dsa/sja1105/sja1105_static_config.h index bc7606899289..779eb6840f05 100644 --- a/drivers/net/dsa/sja1105/sja1105_static_config.h +++ b/drivers/net/dsa/sja1105/sja1105_static_config.h @@ -9,6 +9,8 @@ #include #include +#define SJA1105_SIZE_SPI_MSG_HEADER 4 +#define SJA1105_SIZE_SPI_MSG_MAXLEN (64 * 4) #define SJA1105_SIZE_DEVICE_ID 4 #define SJA1105_SIZE_TABLE_HEADER 12 #define SJA1105_SIZE_SCHEDULE_ENTRY 8