ARM: OMAP2+: UART: Get context loss count to context restore

Avoid unconditional context restore every time we gate uart
clocks. Check whether context loss happened based on which
we can context restore uart regs from uart_port structure.

Signed-off-by: Govindraj.R <govindraj.raja@ti.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de> (for drivers/tty changes)
Signed-off-by: Kevin Hilman <khilman@ti.com>

diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index b3f3284..78ca7e8 100644 (file)
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -33,6 +33,7 @@
 #include <plat/dma.h>
 #include <plat/omap_hwmod.h>
 #include <plat/omap_device.h>
+#include <plat/omap-pm.h>
 
 #include "prm2xxx_3xxx.h"
 #include "pm.h"
@@ -478,6 +479,7 @@ void __init omap_serial_init_port(struct omap_board_data *bdata)
        omap_up.dma_enabled = uart->dma_enabled;
        omap_up.uartclk = OMAP24XX_BASE_BAUD * 16;
        omap_up.flags = UPF_BOOT_AUTOCONF;
+       omap_up.get_context_loss_count = omap_pm_get_dev_context_loss_count;
 
        pdata = &omap_up;
        pdata_size = sizeof(struct omap_uart_port_info);

diff --git a/arch/arm/plat-omap/include/plat/omap-serial.h b/arch/arm/plat-omap/include/plat/omap-serial.h
index 5b913c7..348c9ea 100644 (file)
--- a/arch/arm/plat-omap/include/plat/omap-serial.h
+++ b/arch/arm/plat-omap/include/plat/omap-serial.h
@@ -62,6 +62,8 @@ struct omap_uart_port_info {
        bool                    dma_enabled;    /* To specify DMA Mode */
        unsigned int            uartclk;        /* UART clock rate */
        upf_t                   flags;          /* UPF_* flags */
+
+       int (*get_context_loss_count)(struct device *);
 };
 
 struct uart_omap_dma {
@@ -114,6 +116,7 @@ struct uart_omap_port {
        unsigned char           msr_saved_flags;
        char                    name[20];
        unsigned long           port_activity;
+       u32                     context_loss_cnt;
 };
 
 #endif /* __OMAP_SERIAL_H__ */

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index f5a5ed6..ea4c24a 100644 (file)
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -1440,15 +1440,31 @@ static void serial_omap_restore_context(struct uart_omap_port *up)
 #ifdef CONFIG_PM_RUNTIME
 static int serial_omap_runtime_suspend(struct device *dev)
 {
+       struct uart_omap_port *up = dev_get_drvdata(dev);
+       struct omap_uart_port_info *pdata = dev->platform_data;
+
+       if (!up)
+               return -EINVAL;
+
+       if (pdata->get_context_loss_count)
+               up->context_loss_cnt = pdata->get_context_loss_count(dev);
+
        return 0;
 }
 
 static int serial_omap_runtime_resume(struct device *dev)
 {
        struct uart_omap_port *up = dev_get_drvdata(dev);
+       struct omap_uart_port_info *pdata = dev->platform_data;
 
-       if (up)
-               serial_omap_restore_context(up);
+       if (up) {
+               if (pdata->get_context_loss_count) {
+                       u32 loss_cnt = pdata->get_context_loss_count(dev);
+
+                       if (up->context_loss_cnt != loss_cnt)
+                               serial_omap_restore_context(up);
+               }
+       }
 
        return 0;
 }