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 5843B54BD4; Tue, 27 Feb 2024 13:57:00 +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=1709042220; cv=none; b=ISdhDy9w45mEW/VvPJUyqBsRK7kpr5sIxuFpA9AsU8kW4UrmVmWpXtAW9LNJvYcwsh7sEu6MnAQDcXaOUO5HxU6zlH29xLIW7I2illXg+FzxB7pPIYFT17/GPXfFVL+gbie+MuZdbz7S9Rmnh3jGxINEHbKBBLDnIilmZUaZzgU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709042220; c=relaxed/simple; bh=lzhqZBOeanCTpcUtFtV4OqQtLvvQuvgpOUJ3KpV2duo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ggMZlOZhSDtk6j+nkqUNrhZ81elBbH93hfn10HxEAvHLJ9lFWyTXXl1qhR//Rxy2FXlI4aWvY877Xa81jdbqS4RyIsjLbnLYQDuR1D8iOEoolXJUtOfzBvWXZpmU46ZAywxu+ZVsCUUAWTFkjHlscjnQK97h+EsrgeYTch3AQcc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=s4qMaRjn; 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="s4qMaRjn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D9796C433F1; Tue, 27 Feb 2024 13:56:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1709042220; bh=lzhqZBOeanCTpcUtFtV4OqQtLvvQuvgpOUJ3KpV2duo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=s4qMaRjnl0xPVuX1XTwprAoYAhXYhqnT5kvU8cBCDESTotLah2L5vyE3N6+V29IFz jjO68MnSxuX0dnUv4qWaa3vGBEeE5zTTQefZvGEcxzlbRKYBpb3qpwGAn9VLkv75Ak gXLbLs8DFG5TPJ0+YkxLGUowPn2k8Mn9z4eg2NBc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Lino Sanfilippo Subject: [PATCH 6.6 182/299] serial: amba-pl011: Fix DMA transmission in RS485 mode Date: Tue, 27 Feb 2024 14:24:53 +0100 Message-ID: <20240227131631.700631637@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240227131625.847743063@linuxfoundation.org> References: <20240227131625.847743063@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: Lino Sanfilippo commit 3b69e32e151bc4a4e3c785cbdb1f918d5ee337ed upstream. When DMA is used in RS485 mode make sure that the UARTs tx section is enabled before the DMA buffers are queued for transmission. Cc: stable@vger.kernel.org Fixes: 8d479237727c ("serial: amba-pl011: add RS485 support") Signed-off-by: Lino Sanfilippo Link: https://lore.kernel.org/r/20240216224709.9928-2-l.sanfilippo@kunbus.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/amba-pl011.c | 60 ++++++++++++++++++++-------------------- 1 file changed, 30 insertions(+), 30 deletions(-) --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -1345,11 +1345,41 @@ static void pl011_start_tx_pio(struct ua } } +static void pl011_rs485_tx_start(struct uart_amba_port *uap) +{ + struct uart_port *port = &uap->port; + u32 cr; + + /* Enable transmitter */ + cr = pl011_read(uap, REG_CR); + cr |= UART011_CR_TXE; + + /* Disable receiver if half-duplex */ + if (!(port->rs485.flags & SER_RS485_RX_DURING_TX)) + cr &= ~UART011_CR_RXE; + + if (port->rs485.flags & SER_RS485_RTS_ON_SEND) + cr &= ~UART011_CR_RTS; + else + cr |= UART011_CR_RTS; + + pl011_write(cr, uap, REG_CR); + + if (port->rs485.delay_rts_before_send) + mdelay(port->rs485.delay_rts_before_send); + + uap->rs485_tx_started = true; +} + static void pl011_start_tx(struct uart_port *port) { struct uart_amba_port *uap = container_of(port, struct uart_amba_port, port); + if ((uap->port.rs485.flags & SER_RS485_ENABLED) && + !uap->rs485_tx_started) + pl011_rs485_tx_start(uap); + if (!pl011_dma_tx_start(uap)) pl011_start_tx_pio(uap); } @@ -1431,42 +1461,12 @@ static bool pl011_tx_char(struct uart_am return true; } -static void pl011_rs485_tx_start(struct uart_amba_port *uap) -{ - struct uart_port *port = &uap->port; - u32 cr; - - /* Enable transmitter */ - cr = pl011_read(uap, REG_CR); - cr |= UART011_CR_TXE; - - /* Disable receiver if half-duplex */ - if (!(port->rs485.flags & SER_RS485_RX_DURING_TX)) - cr &= ~UART011_CR_RXE; - - if (port->rs485.flags & SER_RS485_RTS_ON_SEND) - cr &= ~UART011_CR_RTS; - else - cr |= UART011_CR_RTS; - - pl011_write(cr, uap, REG_CR); - - if (port->rs485.delay_rts_before_send) - mdelay(port->rs485.delay_rts_before_send); - - uap->rs485_tx_started = true; -} - /* Returns true if tx interrupts have to be (kept) enabled */ static bool pl011_tx_chars(struct uart_amba_port *uap, bool from_irq) { struct circ_buf *xmit = &uap->port.state->xmit; int count = uap->fifosize >> 1; - if ((uap->port.rs485.flags & SER_RS485_ENABLED) && - !uap->rs485_tx_started) - pl011_rs485_tx_start(uap); - if (uap->port.x_char) { if (!pl011_tx_char(uap, uap->port.x_char, from_irq)) return true;