[PATCHv2 4/8] serial: imx: save and restore context in the suspend path
From: Eduardo Valentin <edubezval@gmail.com>
Date: 2015-08-11 01:36:07
Also in:
linux-serial, lkml
Subsystem:
the rest, tty layer and serial drivers · Maintainers:
Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
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@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <redacted> Cc: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Eduardo Valentin <edubezval@gmail.com> --- 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