From patchwork Tue Apr 13 17:40:15 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Erwan LE RAY X-Patchwork-Id: 420594 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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, 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 8A7E8C43460 for ; Tue, 13 Apr 2021 17:40:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 596FE613BF for ; Tue, 13 Apr 2021 17:40:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232433AbhDMRk7 (ORCPT ); Tue, 13 Apr 2021 13:40:59 -0400 Received: from mx07-00178001.pphosted.com ([185.132.182.106]:44686 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230234AbhDMRk6 (ORCPT ); Tue, 13 Apr 2021 13:40:58 -0400 Received: from pps.filterd (m0241204.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 13DHWjhg029971; Tue, 13 Apr 2021 19:40:23 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foss.st.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=selector1; bh=WVmHBLOEqQLsN3slXuOeeS0dh0JFTB6Rgs+D02bF5a0=; b=78yK8p/Mq+2SWIjG3a45DBzgYXpaoXwOGO0dlwVM4lvfS96J/O95z1X3lgahYuk38e7i WtU0widxjs/W+i23RMEWCNn2WrWQ6FT7D9NG92hp8ht0WSovzez7qnqA1giWM81lV62X 5vliWJyfxLZM4uib8F38kjRpOHGKWUon50g7AHb6cf6v4waIV+FG5fvxsDp3xZowP6Eu 7MisbMjLvOBO4g9n7EnQi37JJ49kBKU7ueeCRvSKhwYwZ8mbnMlwWwIj6/B8tH/3RX45 Pdy+tra8w2yCdhpNGZ/RR5cpifMdXcS+/pSnooCM3gihzmyAIutMLHofoZVBT3+P4KAZ Yw== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 37vrp5f39k-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 13 Apr 2021 19:40:23 +0200 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 68CD710002A; Tue, 13 Apr 2021 19:40:23 +0200 (CEST) Received: from Webmail-eu.st.com (sfhdag2node3.st.com [10.75.127.6]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 5B6E02159E9; Tue, 13 Apr 2021 19:40:23 +0200 (CEST) Received: from localhost (10.75.127.44) by SFHDAG2NODE3.st.com (10.75.127.6) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 13 Apr 2021 19:40:22 +0200 From: Erwan Le Ray To: Greg Kroah-Hartman , Jiri Slaby , Rob Herring , Maxime Coquelin , Alexandre Torgue CC: , , , , , Erwan Le Ray , Fabrice Gasnier , Valentin Caron Subject: [PATCH v2 4/4] serial: stm32: add FIFO threshold configuration Date: Tue, 13 Apr 2021 19:40:15 +0200 Message-ID: <20210413174015.23011-5-erwan.leray@foss.st.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210413174015.23011-1-erwan.leray@foss.st.com> References: <20210413174015.23011-1-erwan.leray@foss.st.com> MIME-Version: 1.0 X-Originating-IP: [10.75.127.44] X-ClientProxiedBy: SFHDAG1NODE3.st.com (10.75.127.3) To SFHDAG2NODE3.st.com (10.75.127.6) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391, 18.0.761 definitions=2021-04-13_12:2021-04-13,2021-04-13 signatures=0 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org From: Fabrice Gasnier Add the support for two optional DT properties, to configure RX and TX FIFO thresholds: - rx-threshold - tx-threshold This replaces hard-coded 8 bytes threshold. Keep 8 as the default value if not specified, for backward compatibility. Signed-off-by: Fabrice Gasnier Signed-off-by: Erwan Le Ray Changes in v2: Change added properties naming as proposed by Rob Herring. diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 4d277804c63e..409cfd15a933 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -312,7 +312,7 @@ static void stm32_usart_tx_interrupt_enable(struct uart_port *port) * Enables TX FIFO threashold irq when FIFO is enabled, * or TX empty irq when FIFO is disabled */ - if (stm32_port->fifoen) + if (stm32_port->fifoen && stm32_port->txftcfg >= 0) stm32_usart_set_bits(port, ofs->cr3, USART_CR3_TXFTIE); else stm32_usart_set_bits(port, ofs->cr1, USART_CR1_TXEIE); @@ -323,7 +323,7 @@ static void stm32_usart_tx_interrupt_disable(struct uart_port *port) struct stm32_port *stm32_port = to_stm32_port(port); const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - if (stm32_port->fifoen) + if (stm32_port->fifoen && stm32_port->txftcfg >= 0) stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_TXFTIE); else stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_TXEIE); @@ -801,9 +801,10 @@ static void stm32_usart_set_termios(struct uart_port *port, cr3 = readl_relaxed(port->membase + ofs->cr3); cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTIE; if (stm32_port->fifoen) { - cr3 &= ~(USART_CR3_TXFTCFG_MASK | USART_CR3_RXFTCFG_MASK); - cr3 |= USART_CR3_TXFTCFG_HALF << USART_CR3_TXFTCFG_SHIFT; - cr3 |= USART_CR3_RXFTCFG_HALF << USART_CR3_RXFTCFG_SHIFT; + if (stm32_port->txftcfg >= 0) + cr3 |= stm32_port->txftcfg << USART_CR3_TXFTCFG_SHIFT; + if (stm32_port->rxftcfg >= 0) + cr3 |= stm32_port->rxftcfg << USART_CR3_RXFTCFG_SHIFT; } if (cflag & CSTOPB) @@ -833,7 +834,8 @@ static void stm32_usart_set_termios(struct uart_port *port, , bits); if (ofs->rtor != UNDEF_REG && (stm32_port->rx_ch || - stm32_port->fifoen)) { + (stm32_port->fifoen && + stm32_port->rxftcfg >= 0))) { if (cflag & CSTOPB) bits = bits + 3; /* 1 start bit + 2 stop bits */ else @@ -1021,6 +1023,39 @@ static const struct uart_ops stm32_uart_ops = { .verify_port = stm32_usart_verify_port, }; +/* + * STM32H7 RX & TX FIFO threshold configuration (CR3 RXFTCFG / TXFTCFG) + * Note: 1 isn't a valid value in RXFTCFG / TXFTCFG. In this case, + * RXNEIE / TXEIE can be used instead of threshold irqs: RXFTIE / TXFTIE. + * So, RXFTCFG / TXFTCFG bitfields values are encoded as array index + 1. + */ +static const u32 stm32h7_usart_fifo_thresh_cfg[] = { 1, 2, 4, 8, 12, 14, 16 }; + +static void stm32_usart_get_ftcfg(struct platform_device *pdev, const char *p, + int *ftcfg) +{ + u32 bytes, i; + + /* DT option to get RX & TX FIFO threshold (default to 8 bytes) */ + if (of_property_read_u32(pdev->dev.of_node, p, &bytes)) + bytes = 8; + + for (i = 0; i < ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg); i++) + if (stm32h7_usart_fifo_thresh_cfg[i] >= bytes) + break; + if (i >= ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg)) + i = ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg) - 1; + + dev_dbg(&pdev->dev, "%s set to %d bytes\n", p, + stm32h7_usart_fifo_thresh_cfg[i]); + + /* Provide FIFO threshold ftcfg (1 is invalid: threshold irq unused) */ + if (i) + *ftcfg = i - 1; + else + *ftcfg = -EINVAL; +} + static void stm32_usart_deinit_port(struct stm32_port *stm32port) { clk_disable_unprepare(stm32port->clk); @@ -1057,6 +1092,12 @@ static int stm32_usart_init_port(struct stm32_port *stm32port, of_property_read_bool(pdev->dev.of_node, "rx-tx-swap"); stm32port->fifoen = stm32port->info->cfg.has_fifo; + if (stm32port->fifoen) { + stm32_usart_get_ftcfg(pdev, "rx-threshold", + &stm32port->rxftcfg); + stm32_usart_get_ftcfg(pdev, "tx-threshold", + &stm32port->txftcfg); + } res = platform_get_resource(pdev, IORESOURCE_MEM, 0); port->membase = devm_ioremap_resource(&pdev->dev, res); diff --git a/drivers/tty/serial/stm32-usart.h b/drivers/tty/serial/stm32-usart.h index 77d1ac082e89..07ac291328cd 100644 --- a/drivers/tty/serial/stm32-usart.h +++ b/drivers/tty/serial/stm32-usart.h @@ -216,12 +216,6 @@ struct stm32_usart_info stm32h7_info = { #define USART_CR3_TXFTCFG_MASK GENMASK(31, 29) /* H7 */ #define USART_CR3_TXFTCFG_SHIFT 29 /* H7 */ -/* TX FIFO threashold set to half of its depth */ -#define USART_CR3_TXFTCFG_HALF 0x2 - -/* RX FIFO threashold set to half of its depth */ -#define USART_CR3_RXFTCFG_HALF 0x2 - /* USART_GTPR */ #define USART_GTPR_PSC_MASK GENMASK(7, 0) #define USART_GTPR_GT_MASK GENMASK(15, 8) @@ -273,6 +267,8 @@ struct stm32_port { bool hw_flow_control; bool swap; /* swap RX & TX pins */ bool fifoen; + int rxftcfg; /* RX FIFO threshold CFG */ + int txftcfg; /* TX FIFO threshold CFG */ bool wakeup_src; int rdr_mask; /* receive data register mask */ struct mctrl_gpios *gpios; /* modem control gpios */