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authorEduardo Valentin <edubezval@gmail.com>2015-08-11 20:21:23 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-08-15 03:23:25 +0300
commitc868cbb7e5c6d3c74b8d38c7c356444f2c807c28 (patch)
tree1ddfcafed92387d2e6a5eb272e938560e1a51d93 /drivers/tty
parentbc85734b126f813ba46265c2d3a84c8839cb2e54 (diff)
downloadlinux-c868cbb7e5c6d3c74b8d38c7c356444f2c807c28.tar.xz
serial: imx: save and restore context in the suspend path
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 Estevam <festevam@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Eduardo Valentin <edubezval@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/imx.c58
1 files changed, 37 insertions, 21 deletions
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 167dea1adf90..fe3d41cc8416 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -217,6 +217,7 @@ struct imx_port {
unsigned int dma_tx_nents;
wait_queue_head_t dma_wait;
unsigned int saved_reg[10];
+ bool context_saved;
};
struct imx_port_ucrs {
@@ -1972,6 +1973,40 @@ static int serial_imx_remove(struct platform_device *pdev)
return uart_remove_one_port(&imx_reg, &sport->port);
}
+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 + UESC);
+ writel(sport->saved_reg[6], sport->port.membase + UTIM);
+ writel(sport->saved_reg[7], sport->port.membase + UBIR);
+ writel(sport->saved_reg[8], sport->port.membase + UBMR);
+ writel(sport->saved_reg[9], sport->port.membase + IMX21_UTS);
+ writel(sport->saved_reg[0], sport->port.membase + UCR1);
+ writel(sport->saved_reg[1] | UCR2_SRST, 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 + UESC);
+ sport->saved_reg[6] = readl(sport->port.membase + UTIM);
+ sport->saved_reg[7] = readl(sport->port.membase + UBIR);
+ sport->saved_reg[8] = readl(sport->port.membase + UBMR);
+ sport->saved_reg[9] = 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;
@@ -2001,17 +2036,7 @@ static int imx_serial_port_suspend_noirq(struct device *dev)
if (ret)
return ret;
- /* 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 + UESC);
- sport->saved_reg[6] = readl(sport->port.membase + UTIM);
- sport->saved_reg[7] = readl(sport->port.membase + UBIR);
- sport->saved_reg[8] = readl(sport->port.membase + UBMR);
- sport->saved_reg[9] = readl(sport->port.membase + IMX21_UTS);
+ serial_imx_save_context(sport);
clk_disable(sport->clk_ipg);
@@ -2028,16 +2053,7 @@ static int imx_serial_port_resume_noirq(struct device *dev)
if (ret)
return ret;
- writel(sport->saved_reg[4], sport->port.membase + UFCR);
- writel(sport->saved_reg[5], sport->port.membase + UESC);
- writel(sport->saved_reg[6], sport->port.membase + UTIM);
- writel(sport->saved_reg[7], sport->port.membase + UBIR);
- writel(sport->saved_reg[8], sport->port.membase + UBMR);
- writel(sport->saved_reg[9], sport->port.membase + IMX21_UTS);
- writel(sport->saved_reg[0], sport->port.membase + UCR1);
- writel(sport->saved_reg[1] | UCR2_SRST, sport->port.membase + UCR2);
- writel(sport->saved_reg[2], sport->port.membase + UCR3);
- writel(sport->saved_reg[3], sport->port.membase + UCR4);
+ serial_imx_restore_context(sport);
clk_disable(sport->clk_ipg);