Hi Alexandre,
On 03/02/2017 23:53, Alexandre Belloni wrote:
> When going to suspend, the UART registers may be lost because the power to
> VDDcore is cut. This is not an issue in the normal case but when
> no_console_suspend is used, we need to restore the registers in order to
> get a functional console.
>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/tty/serial/atmel_serial.c | 44 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 44 insertions(+)
>
> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index 168b10cad47b..22e0a73c0cb7 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -175,6 +175,17 @@ struct atmel_uart_port {
> unsigned int pending_status;
> spinlock_t lock_suspended;
>
> + struct {
> + u32 cr;
> + u32 mr;
> + u32 imr;
> + u32 brgr;
> + u32 rtor;
> + u32 ttgr;
> + u32 fmr;
> + u32 fimr;
> + } cache;
> +
As struct cache is only used in suspend()/resume() we could add:
#ifdef CONFIG_PM / #endif
to remove it from atmel_uart_port when PM is not selected.
Even if I'm not a big fan of ifdefs, the suspend code is already
compiled out with #ifdef CONFIG_PM, so, at least, it would be consistent.
> int (*prepare_rx)(struct uart_port *port);
> int (*prepare_tx)(struct uart_port *port);
> void (*schedule_rx)(struct uart_port *port);
> @@ -2649,6 +2660,20 @@ static int atmel_serial_suspend(struct platform_device *pdev,
> cpu_relax();
> }
>
> + if (atmel_is_console_port(port) && !console_suspend_enabled) {
> + /* Cache register values as we won't get a full shutdown/startup
> + * cycle
> + */
> + atmel_port->cache.mr = atmel_uart_readl(port, ATMEL_US_MR);
> + atmel_port->cache.imr = atmel_uart_readl(port, ATMEL_US_IMR);
> + atmel_port->cache.brgr = atmel_uart_readl(port, ATMEL_US_BRGR);
> + atmel_port->cache.rtor = atmel_uart_readl(port,
> + atmel_port->rtor);
> + atmel_port->cache.ttgr = atmel_uart_readl(port, ATMEL_US_TTGR);
> + atmel_port->cache.fmr = atmel_uart_readl(port, ATMEL_US_FMR);
> + atmel_port->cache.fimr = atmel_uart_readl(port, ATMEL_US_FIMR);
> + }
> +
> /* we can not wake up if we're running on slow clock */
> atmel_port->may_wakeup = device_may_wakeup(&pdev->dev);
> if (atmel_serial_clk_will_stop()) {
> @@ -2671,6 +2696,25 @@ static int atmel_serial_resume(struct platform_device *pdev)
> struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
> unsigned long flags;
>
> + if (atmel_is_console_port(port) && !console_suspend_enabled) {
> + atmel_uart_writel(port, ATMEL_US_MR, atmel_port->cache.mr);
> + atmel_uart_writel(port, ATMEL_US_IER, atmel_port->cache.imr);
> + atmel_uart_writel(port, ATMEL_US_BRGR, atmel_port->cache.brgr);
> + atmel_uart_writel(port, atmel_port->rtor,
> + atmel_port->cache.rtor);
> + atmel_uart_writel(port, ATMEL_US_TTGR, atmel_port->cache.ttgr);
> +
> + if (atmel_port->fifo_size) {
> + atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_FIFOEN |
> + ATMEL_US_RXFCLR | ATMEL_US_TXFLCLR);
> + atmel_uart_writel(port, ATMEL_US_FMR,
> + atmel_port->cache.fmr);
> + atmel_uart_writel(port, ATMEL_US_FIER,
> + atmel_port->cache.fimr);
> + }
> + atmel_start_rx(port);
> + }
> +
> spin_lock_irqsave(&atmel_port->lock_suspended, flags);
> if (atmel_port->pending) {
> atmel_handle_receive(port, atmel_port->pending);
>
Thanks !
Richard.
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