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@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Jiri Slaby <jslaby@xxxxxxxx>
Cc: linux-serial@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Eduardo Valentin <edubezval@xxxxxxxxx>
---
drivers/tty/serial/imx.c | 58 ++++++++++++++++++++++++++++++------------------
1 file changed, 37 insertions(+), 21 deletions(-)
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 167dea1..fe3d41c 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);
--
2.5.0
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