Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933297AbbHISVD (ORCPT ); Sun, 9 Aug 2015 14:21:03 -0400 Received: from mail-pa0-f41.google.com ([209.85.220.41]:34751 "EHLO mail-pa0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933181AbbHISTY (ORCPT ); Sun, 9 Aug 2015 14:19:24 -0400 From: Eduardo Valentin To: Greg Kroah-Hartman , Jiri Slaby , Fabio Stevam Cc: Linux PM , Eduardo Valentin , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 5/8] serial: imx: save and restore context in the suspend path Date: Sun, 9 Aug 2015 11:19:06 -0700 Message-Id: <1439144349-10494-6-git-send-email-edubezval@gmail.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1439144349-10494-1-git-send-email-edubezval@gmail.com> References: <1439144349-10494-1-git-send-email-edubezval@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3260 Lines: 93 This change teaches the imx serial driver to save its context and restore it across suspend and resume path. To do so, it introduces serial_imx_restore_context() and serial_imx_save_context() functions. They use a shadow set of registers to save key registers and restore them accordingly. These functions can be reused on other situations, when the device context is lost. Cc: Fabio Stevam Cc: Greg Kroah-Hartman Cc: Jiri Slaby Cc: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Eduardo Valentin --- drivers/tty/serial/imx.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index a03855d..494b182 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -217,6 +217,8 @@ struct imx_port { unsigned int tx_bytes; unsigned int dma_tx_nents; wait_queue_head_t dma_wait; + unsigned int saved_reg[8]; + bool context_saved; }; struct imx_port_ucrs { @@ -1803,6 +1805,36 @@ static struct uart_driver imx_reg = { .cons = IMX_CONSOLE, }; +static void serial_imx_restore_context(struct imx_port *sport) +{ + if (!sport->context_saved) + return; + + writel(sport->saved_reg[4], sport->port.membase + UFCR); + writel(sport->saved_reg[5], sport->port.membase + UBIR); + writel(sport->saved_reg[6], sport->port.membase + UBMR); + writel(sport->saved_reg[7], sport->port.membase + IMX21_UTS); + writel(sport->saved_reg[0], sport->port.membase + UCR1); + writel(sport->saved_reg[1] | 0x1, sport->port.membase + UCR2); + writel(sport->saved_reg[2], sport->port.membase + UCR3); + writel(sport->saved_reg[3], sport->port.membase + UCR4); + sport->context_saved = false; +} + +static void serial_imx_save_context(struct imx_port *sport) +{ + /* Save necessary regs */ + sport->saved_reg[0] = readl(sport->port.membase + UCR1); + sport->saved_reg[1] = readl(sport->port.membase + UCR2); + sport->saved_reg[2] = readl(sport->port.membase + UCR3); + sport->saved_reg[3] = readl(sport->port.membase + UCR4); + sport->saved_reg[4] = readl(sport->port.membase + UFCR); + sport->saved_reg[5] = readl(sport->port.membase + UBIR); + sport->saved_reg[6] = readl(sport->port.membase + UBMR); + sport->saved_reg[7] = readl(sport->port.membase + IMX21_UTS); + sport->context_saved = true; +} + static void serial_imx_enable_wakeup(struct imx_port *sport, bool on) { unsigned int val; @@ -1826,6 +1858,7 @@ static int serial_imx_suspend(struct device *dev) { struct imx_port *sport = dev_get_drvdata(dev); + serial_imx_save_context(sport); /* enable wakeup from i.MX UART */ serial_imx_enable_wakeup(sport, true); @@ -1841,6 +1874,7 @@ static int serial_imx_resume(struct device *dev) /* disable wakeup from i.MX UART */ serial_imx_enable_wakeup(sport, false); + serial_imx_restore_context(sport); uart_resume_port(&imx_reg, &sport->port); return 0; -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/