From patchwork Thu Dec 21 23:18:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hugo Villeneuve X-Patchwork-Id: 757428 Received: from mail.hugovil.com (mail.hugovil.com [162.243.120.170]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CAC1E7948F; Thu, 21 Dec 2023 23:18:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=hugovil.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=hugovil.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=hugovil.com header.i=@hugovil.com header.b="V5h8PKkc" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=hugovil.com ; s=x; h=Subject:Content-Transfer-Encoding:MIME-Version:Message-Id:Date:Cc:To :From:subject:date:message-id:reply-to; bh=NqyaA+da2u2LMAkVhsOx0NUe18UOdygrK1MLZ2OBgRY=; b=V5h8PKkc85RTZfJ5IhPCC9oz6j YBWoG+wqv9zw+zlALSXf4wx1n/P0k+dwMLwRMZYUWyR575Oazb9RUQ7dYu8y6iBXrzAOAalY04KL5 xB6waXC1vIc/aLu0IylvmtfpnBehkxPJuUOEbKNTn86MNCZDfPGptD9GvFpEfFoovvto=; Received: from modemcable168.174-80-70.mc.videotron.ca ([70.80.174.168]:52484 helo=pettiford.lan) by mail.hugovil.com with esmtpa (Exim 4.92) (envelope-from ) id 1rGSJI-00025W-WC; Thu, 21 Dec 2023 18:18:37 -0500 From: Hugo Villeneuve To: gregkh@linuxfoundation.org, jirislaby@kernel.org, kubakici@wp.pl, indrakanti_ram@hotmail.com, phil@raspberrypi.org Cc: linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, hugo@hugovil.com, Hugo Villeneuve , stable@vger.kernel.org, Andy Shevchenko Date: Thu, 21 Dec 2023 18:18:11 -0500 Message-Id: <20231221231823.2327894-5-hugo@hugovil.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231221231823.2327894-1-hugo@hugovil.com> References: <20231221231823.2327894-1-hugo@hugovil.com> Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SA-Exim-Connect-IP: 70.80.174.168 X-SA-Exim-Mail-From: hugo@hugovil.com X-Spam-Level: X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * -0.0 T_SCC_BODY_TEXT_LINE No description available. Subject: [PATCH v2 04/16] serial: sc16is7xx: remove obsolete loop in sc16is7xx_port_irq() X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on mail.hugovil.com) From: Hugo Villeneuve Commit 834449872105 ("sc16is7xx: Fix for multi-channel stall") changed sc16is7xx_port_irq() from looping multiple times when there was still interrupts to serve. It simply changed the do {} while(1) loop to a do {} while(0) loop, which makes the loop itself now obsolete. Clean the code by removing this obsolete do {} while(0) loop. Fixes: 834449872105 ("sc16is7xx: Fix for multi-channel stall") Cc: stable@vger.kernel.org Suggested-by: Andy Shevchenko Signed-off-by: Hugo Villeneuve --- drivers/tty/serial/sc16is7xx.c | 81 ++++++++++++++++------------------ 1 file changed, 39 insertions(+), 42 deletions(-) diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index ced2446909a2..44a11c89c949 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -725,58 +725,55 @@ static void sc16is7xx_update_mlines(struct sc16is7xx_one *one) static bool sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno) { bool rc = true; + unsigned int iir, rxlen; struct uart_port *port = &s->p[portno].port; struct sc16is7xx_one *one = to_sc16is7xx_one(port, port); mutex_lock(&one->efr_lock); - do { - unsigned int iir, rxlen; + iir = sc16is7xx_port_read(port, SC16IS7XX_IIR_REG); + if (iir & SC16IS7XX_IIR_NO_INT_BIT) { + rc = false; + goto out_port_irq; + } - iir = sc16is7xx_port_read(port, SC16IS7XX_IIR_REG); - if (iir & SC16IS7XX_IIR_NO_INT_BIT) { - rc = false; - goto out_port_irq; - } + iir &= SC16IS7XX_IIR_ID_MASK; - iir &= SC16IS7XX_IIR_ID_MASK; + switch (iir) { + case SC16IS7XX_IIR_RDI_SRC: + case SC16IS7XX_IIR_RLSE_SRC: + case SC16IS7XX_IIR_RTOI_SRC: + case SC16IS7XX_IIR_XOFFI_SRC: + rxlen = sc16is7xx_port_read(port, SC16IS7XX_RXLVL_REG); - switch (iir) { - case SC16IS7XX_IIR_RDI_SRC: - case SC16IS7XX_IIR_RLSE_SRC: - case SC16IS7XX_IIR_RTOI_SRC: - case SC16IS7XX_IIR_XOFFI_SRC: - rxlen = sc16is7xx_port_read(port, SC16IS7XX_RXLVL_REG); + /* + * There is a silicon bug that makes the chip report a + * time-out interrupt but no data in the FIFO. This is + * described in errata section 18.1.4. + * + * When this happens, read one byte from the FIFO to + * clear the interrupt. + */ + if (iir == SC16IS7XX_IIR_RTOI_SRC && !rxlen) + rxlen = 1; - /* - * There is a silicon bug that makes the chip report a - * time-out interrupt but no data in the FIFO. This is - * described in errata section 18.1.4. - * - * When this happens, read one byte from the FIFO to - * clear the interrupt. - */ - if (iir == SC16IS7XX_IIR_RTOI_SRC && !rxlen) - rxlen = 1; - - if (rxlen) - sc16is7xx_handle_rx(port, rxlen, iir); - break; + if (rxlen) + sc16is7xx_handle_rx(port, rxlen, iir); + break; /* CTSRTS interrupt comes only when CTS goes inactive */ - case SC16IS7XX_IIR_CTSRTS_SRC: - case SC16IS7XX_IIR_MSI_SRC: - sc16is7xx_update_mlines(one); - break; - case SC16IS7XX_IIR_THRI_SRC: - sc16is7xx_handle_tx(port); - break; - default: - dev_err_ratelimited(port->dev, - "ttySC%i: Unexpected interrupt: %x", - port->line, iir); - break; - } - } while (0); + case SC16IS7XX_IIR_CTSRTS_SRC: + case SC16IS7XX_IIR_MSI_SRC: + sc16is7xx_update_mlines(one); + break; + case SC16IS7XX_IIR_THRI_SRC: + sc16is7xx_handle_tx(port); + break; + default: + dev_err_ratelimited(port->dev, + "ttySC%i: Unexpected interrupt: %x", + port->line, iir); + break; + } out_port_irq: mutex_unlock(&one->efr_lock);