From patchwork Tue Jul 17 13:43:08 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxime Chevallier X-Patchwork-Id: 10529441 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id E07B36020A for ; Tue, 17 Jul 2018 13:44:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CE0DD205A8 for ; Tue, 17 Jul 2018 13:44:04 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C05DA288F3; Tue, 17 Jul 2018 13:44:04 +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=unavailable 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 68A17205A8 for ; Tue, 17 Jul 2018 13:44:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731740AbeGQOQO (ORCPT ); Tue, 17 Jul 2018 10:16:14 -0400 Received: from mail.bootlin.com ([62.4.15.54]:40847 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731716AbeGQOQO (ORCPT ); Tue, 17 Jul 2018 10:16:14 -0400 Received: by mail.bootlin.com (Postfix, from userid 110) id 7CE232091A; Tue, 17 Jul 2018 15:43:28 +0200 (CEST) Received: from mc-bl-xps13.lan (AAubervilliers-681-1-27-161.w90-88.abo.wanadoo.fr [90.88.147.161]) by mail.bootlin.com (Postfix) with ESMTPSA id 3CA74208C4; Tue, 17 Jul 2018 15:43:18 +0200 (CEST) From: Maxime Chevallier To: Mark Brown Cc: Maxime Chevallier , linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, thomas.petazzoni@bootlin.com, alexandre.belloni@bootlin.com Subject: [PATCH 2/5] spi: imx: Use dynamic bursts only when bits_per_word is 8, 16 or 32 Date: Tue, 17 Jul 2018 15:43:08 +0200 Message-Id: <20180717134311.26780-3-maxime.chevallier@bootlin.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20180717134311.26780-1-maxime.chevallier@bootlin.com> References: <20180717134311.26780-1-maxime.chevallier@bootlin.com> 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 The dynamic bursts mode allows to group together multiple words into a single burst. To do so, it's necessary that words can be packed into the 32-bits FIFO entries, so we can't allow using this mode with bit_per_words different to 8, 16 or 32. This prevents shitfing out extra clock ticks for transfers with bit_per_word values not aligned on 8 bits. With that , we are sure that only the correct number of bits is shifted out at each transfer, so we don't need to mask out the remaining parts of the words. Signed-off-by: Maxime Chevallier --- drivers/spi/spi-imx.c | 23 +++++++++-------------- 1 file changed, 9 insertions(+), 14 deletions(-) diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c index d75153c995af..ecafbda5ec94 100644 --- a/drivers/spi/spi-imx.c +++ b/drivers/spi/spi-imx.c @@ -95,7 +95,6 @@ struct spi_imx_data { const void *tx_buf; unsigned int txfifo; /* number of words pushed in tx FIFO */ unsigned int dynamic_burst, read_u32; - unsigned int word_mask; /* Slave mode */ bool slave_mode; @@ -291,7 +290,6 @@ static void spi_imx_buf_rx_swap_u32(struct spi_imx_data *spi_imx) else if (bytes_per_word == 2) val = (val << 16) | (val >> 16); #endif - val &= spi_imx->word_mask; *(u32 *)spi_imx->rx_buf = val; spi_imx->rx_buf += sizeof(u32); } @@ -322,7 +320,6 @@ static void spi_imx_buf_tx_swap_u32(struct spi_imx_data *spi_imx) if (spi_imx->tx_buf) { val = *(u32 *)spi_imx->tx_buf; - val &= spi_imx->word_mask; spi_imx->tx_buf += sizeof(u32); } @@ -1102,25 +1099,23 @@ static int spi_imx_setupxfer(struct spi_device *spi, spi_imx->bits_per_word = t->bits_per_word; spi_imx->speed_hz = t->speed_hz; - /* Initialize the functions for transfer */ - if (spi_imx->devtype_data->dynamic_burst && !spi_imx->slave_mode) { - u32 mask; + /* + * Initialize the functions for transfer. To transfer non byte-aligned + * words, we have to use multiple word-size bursts, we can't use + * dynamic_burst in that case. + */ + if (spi_imx->devtype_data->dynamic_burst && !spi_imx->slave_mode && + (spi_imx->bits_per_word == 8 || + spi_imx->bits_per_word == 16 || + spi_imx->bits_per_word == 32)) { spi_imx->read_u32 = 1; - mask = (1 << spi_imx->bits_per_word) - 1; spi_imx->rx = spi_imx_buf_rx_swap; spi_imx->tx = spi_imx_buf_tx_swap; spi_imx->dynamic_burst = 1; spi_imx->remainder = t->len; - if (spi_imx->bits_per_word <= 8) - spi_imx->word_mask = mask << 24 | mask << 16 - | mask << 8 | mask; - else if (spi_imx->bits_per_word <= 16) - spi_imx->word_mask = mask << 16 | mask; - else - spi_imx->word_mask = mask; } else { if (spi_imx->bits_per_word <= 8) { spi_imx->rx = spi_imx_buf_rx_u8;