提交 6a5f0e2f 编写于 作者: A Alexandre Belloni 提交者: Greg Kroah-Hartman

tty/serial: atmel: ensure state is restored after suspending

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: NAlexandre Belloni <alexandre.belloni@free-electrons.com>
Reviewed-by: NNicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
上级 424d7918
......@@ -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;
int (*prepare_rx)(struct uart_port *port);
int (*prepare_tx)(struct uart_port *port);
void (*schedule_rx)(struct uart_port *port);
......@@ -2659,6 +2670,20 @@ 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()) {
......@@ -2681,6 +2706,25 @@ 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);
......
Markdown is supported
0% .
You are about to add 0 people to the discussion. Proceed with caution.
先完成此消息的编辑!
想要评论请 注册