From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 AA49372223; Mon, 29 Jan 2024 17:15:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706548506; cv=none; b=iynx2uAfGZm8BS2Wtcbs9fhBUPAH67MZ+rONBkbz8g4c1KN7FkJc+ioi0qw8f+cgq1BjHc61RCxanGERLyZQ1dP723b7ivVfacfSS6CrU6AkifA3vNwcOn8jcTjerQYZxjOEY5FvHzAR+MoZWfju/Vwtn42VxqnfatpUygvOLgQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706548506; c=relaxed/simple; bh=Tq5IvIdtyys7oEKni5Hui40byVsbEuFLzTzQI4OVFYQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BgBEvkr982wWrr44upG/mWRoJZrE2gRt7WqKMUf6afpQrSe43nAMjxwLx6mKK7PJkNAIbgvYpyilLWDUuaHfFPiwwZJGJX37LCAU1seeyBzR5T3F84N8IiQpzT05vNXMZzuS8o9/64Ed8C5X2Of1MN3BmrqJ2e6+y6mL44qCrVg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=KREzeYIh; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="KREzeYIh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 70F53C433F1; Mon, 29 Jan 2024 17:15:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1706548506; bh=Tq5IvIdtyys7oEKni5Hui40byVsbEuFLzTzQI4OVFYQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KREzeYIh4Jh7AxwNkuQlRDTVrnU2Re1dDh89ofvzGiCGlTCd9h/VI2ir833PhK3Ri MjPfiFWDfMdo/wNypLqEBpwYIk1mbTo86DCGweV2YwKUSs01Yra+HzWc6qM2alpMY3 C4Eabgy5sBcTME8H7Og9eoznMm10OWJEAElEjXcM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Andy Shevchenko , Hugo Villeneuve Subject: [PATCH 6.6 135/331] serial: sc16is7xx: remove obsolete loop in sc16is7xx_port_irq() Date: Mon, 29 Jan 2024 09:03:19 -0800 Message-ID: <20240129170018.892507399@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240129170014.969142961@linuxfoundation.org> References: <20240129170014.969142961@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hugo Villeneuve commit ed647256e8f226241ecff7baaecdb8632ffc7ec1 upstream. 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: Suggested-by: Andy Shevchenko Signed-off-by: Hugo Villeneuve Link: https://lore.kernel.org/r/20231221231823.2327894-5-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/sc16is7xx.c | 89 +++++++++++++++++++---------------------- 1 file changed, 43 insertions(+), 46 deletions(-) --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -724,58 +724,55 @@ static void sc16is7xx_update_mlines(stru 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_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); - - /* - * 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; + 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; + + 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; + + 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);