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 <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Eduardo Valentin <[email protected]>
---
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
Hi Eduardo,
On Sun, Aug 9, 2015 at 3:19 PM, Eduardo Valentin <[email protected]> wrote:
> 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 <[email protected]>
s/Stevam/Estevam (applies to all the patches)
> Cc: Greg Kroah-Hartman <[email protected]>
> Cc: Jiri Slaby <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Eduardo Valentin <[email protected]>
> ---
> 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;
> +}
This seems to be similar to what Shenwei posted earlier:
http://lists.infradead.org/pipermail/linux-arm-kernel/2015-July/360841.html
Regards,
Fabio Estevam
On Mon, Aug 10, 2015 at 12:30:18AM -0300, Fabio Estevam wrote:
> Hi Eduardo,
>
> On Sun, Aug 9, 2015 at 3:19 PM, Eduardo Valentin <[email protected]> wrote:
> > 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 <[email protected]>
>
> s/Stevam/Estevam (applies to all the patches)
Sorry, my bad here.
>
> > Cc: Greg Kroah-Hartman <[email protected]>
> > Cc: Jiri Slaby <[email protected]>
> > Cc: [email protected]
> > Cc: [email protected]
> > Signed-off-by: Eduardo Valentin <[email protected]>
> > ---
> > 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;
> > +}
>
> This seems to be similar to what Shenwei posted earlier:
> http://lists.infradead.org/pipermail/linux-arm-kernel/2015-July/360841.html
OK. Do you know what is the status of that patch set?
did it get accepted by any tree so far?
>
> Regards,
>
> Fabio Estevam
On Mon, Aug 10, 2015 at 1:04 AM, Eduardo Valentin <[email protected]> wrote:
> OK. Do you know what is the status of that patch set?
>
> did it get accepted by any tree so far?
It is in linux-next.
On Mon, Aug 10, 2015 at 09:17:55AM -0300, Fabio Estevam wrote:
> On Mon, Aug 10, 2015 at 1:04 AM, Eduardo Valentin <[email protected]> wrote:
>
> > OK. Do you know what is the status of that patch set?
> >
> > did it get accepted by any tree so far?
>
> It is in linux-next.
Ok. I am rebasing my changes then. I will fix the naming issue too.
BR,
Eduardo Valentin