Hi Eduardo,
On Sun, Aug 9, 2015 at 3:19 PM, Eduardo Valentin <edubezval@xxxxxxxxx> 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 <festevam@xxxxxxxxx>
s/Stevam/Estevam (applies to all the patches)
> 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 | 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
--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
