From patchwork Fri Sep 6 13:13:30 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Johan Hovold X-Patchwork-Id: 826227 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 E43301CBE8A; Fri, 6 Sep 2024 13:14:58 +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=1725628499; cv=none; b=J0inCuaFKaFk68bBiPFNGXQZrEWW4U5k8Abcg9pWNlO28aj4t156131bFPhOV5yWnT06k2OSuXlO9AeRqkLTCv0mufo9ZVBBOm725TaLrK/p8jnq3PRHFP2MLIFtPgJUtGcMbaCZiMlUUmHrnyAVJdnHnR43PZVgMqisEBNI+oM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725628499; c=relaxed/simple; bh=m62cY20WvDhqd0wyAzMWpkpsp6ZbaGEV0lCpZuGNUhQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=F7I09g2bj/e0XUVz1bi8DhINhFjvMal33ccKmjler2x2P7pD9BflHliX2wujCuY7NxRQ+u/+XMMdGP8UWk1jib1hZZZ+8x3+XaymT59HdeubA7Rmnj1cAb5k46CsUX30iibfcyXr2xhOw19Z1ibeAc/Rx84x4ZuunP4DSgMLLxM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AZn20ZJ3; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="AZn20ZJ3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8F8FFC4CEC5; Fri, 6 Sep 2024 13:14:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725628498; bh=m62cY20WvDhqd0wyAzMWpkpsp6ZbaGEV0lCpZuGNUhQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AZn20ZJ3LBYXdmg36f0LtsjNgedqqA67AKgasEf8HgO0vrkcdBG9Pg068URPLaMZr i2bmUe69ks8ygpAutk3uxH+cXpYm5BvcRQ33Ga1pyCHwsOGg19Eq77Vf6wnMr1Gb3U rMaVOnYCU4xI+nt9b83ExOmpRU3T/aVLd8Oa4N/BIHjWUBHTUGOSr/t3ngv2hoWSMq 68R5JXCzb+I1FdG3BWdbg5gOeoiuHMfOCmDaXqZtenEm/GXP5UgaTnleEFHfGKR/GJ 7sWvqEMYGk8/vNmG0qxncdoZf5whfIpq6lXyyA3Sm8c4GBNUhoEYKAeuqEM3O7lgGZ 7s0ePOktEDMoQ== Received: from johan by xi.lan with local (Exim 4.97.1) (envelope-from ) id 1smYo3-000000006Ae-0yqh; Fri, 06 Sep 2024 15:15:19 +0200 From: Johan Hovold To: Greg Kroah-Hartman Cc: Jiri Slaby , Bjorn Andersson , Konrad Dybcio , Douglas Anderson , =?utf-8?q?N=C3=ADcolas_F_=2E_R_?= =?utf-8?q?=2E_A_=2E_Prado?= , linux-arm-msm@vger.kernel.org, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Johan Hovold , stable@vger.kernel.org Subject: [PATCH v2 2/8] serial: qcom-geni: fix false console tx restart Date: Fri, 6 Sep 2024 15:13:30 +0200 Message-ID: <20240906131336.23625-3-johan+linaro@kernel.org> X-Mailer: git-send-email 2.44.2 In-Reply-To: <20240906131336.23625-1-johan+linaro@kernel.org> References: <20240906131336.23625-1-johan+linaro@kernel.org> Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Commit 663abb1a7a7f ("tty: serial: qcom_geni_serial: Fix UART hang") addressed an issue with stalled tx after the console code interrupted the last bytes of a tx command by reenabling the watermark interrupt if there is data in write buffer. This can however break software flow control by re-enabling tx after the user has stopped it. Address the original issue by not clearing the CMD_DONE flag after polling for command completion. This allows the interrupt handler to start another transfer when the CMD_DONE interrupt has not been disabled due to flow control. Fixes: c4f528795d1a ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP") Fixes: 663abb1a7a7f ("tty: serial: qcom_geni_serial: Fix UART hang") Cc: stable@vger.kernel.org # 4.17 Reviewed-by: Douglas Anderson Tested-by: Nícolas F. R. A. Prado Signed-off-by: Johan Hovold --- drivers/tty/serial/qcom_geni_serial.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 309c0bddf26a..b88435c0ea50 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -306,18 +306,16 @@ static void qcom_geni_serial_setup_tx(struct uart_port *uport, u32 xmit_size) static void qcom_geni_serial_poll_tx_done(struct uart_port *uport) { int done; - u32 irq_clear = M_CMD_DONE_EN; done = qcom_geni_serial_poll_bit(uport, SE_GENI_M_IRQ_STATUS, M_CMD_DONE_EN, true); if (!done) { writel(M_GENI_CMD_ABORT, uport->membase + SE_GENI_M_CMD_CTRL_REG); - irq_clear |= M_CMD_ABORT_EN; qcom_geni_serial_poll_bit(uport, SE_GENI_M_IRQ_STATUS, M_CMD_ABORT_EN, true); + writel(M_CMD_ABORT_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); } - writel(irq_clear, uport->membase + SE_GENI_M_IRQ_CLEAR); } static void qcom_geni_serial_abort_rx(struct uart_port *uport) @@ -378,6 +376,7 @@ static void qcom_geni_serial_poll_put_char(struct uart_port *uport, unsigned char c) { writel(DEF_TX_WM, uport->membase + SE_GENI_TX_WATERMARK_REG); + writel(M_CMD_DONE_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); qcom_geni_serial_setup_tx(uport, 1); WARN_ON(!qcom_geni_serial_poll_bit(uport, SE_GENI_M_IRQ_STATUS, M_TX_FIFO_WATERMARK_EN, true)); @@ -422,6 +421,7 @@ __qcom_geni_serial_console_write(struct uart_port *uport, const char *s, } writel(DEF_TX_WM, uport->membase + SE_GENI_TX_WATERMARK_REG); + writel(M_CMD_DONE_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); qcom_geni_serial_setup_tx(uport, bytes_to_send); for (i = 0; i < count; ) { size_t chars_to_write = 0; @@ -463,7 +463,6 @@ static void qcom_geni_serial_console_write(struct console *co, const char *s, bool locked = true; unsigned long flags; u32 geni_status; - u32 irq_en; WARN_ON(co->index < 0 || co->index >= GENI_UART_CONS_PORTS); @@ -495,12 +494,6 @@ static void qcom_geni_serial_console_write(struct console *co, const char *s, * has been sent, in which case we need to look for done first. */ qcom_geni_serial_poll_tx_done(uport); - - if (!kfifo_is_empty(&uport->state->port.xmit_fifo)) { - irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN); - writel(irq_en | M_TX_FIFO_WATERMARK_EN, - uport->membase + SE_GENI_M_IRQ_EN); - } } __qcom_geni_serial_console_write(uport, s, count);