From: Teerth Reddy <tee...@ti.com>

Currently UART context save is done in idle thread thru a call
to omap_uart_prepare_idle irrespective of what power state is 
attained by the power domain to which the UART belongs to. This
patch allows omap_uart_prepare_idle to take power state as a 
parameter and this function in turn does a uart context save 
only if the passed power state is PWRDM_POWER_OFF. In the restore
path a restore will happen only if a valid save has happened.

Signed-off-by: Thara Gopinath <th...@ti.com>
Signed-off-by: Teerth Reddy <tee...@ti.com>
---
 arch/arm/mach-omap2/pm34xx.c             |    6 +++---
 arch/arm/mach-omap2/serial.c             |   26 ++++++++++++++++----------
 arch/arm/plat-omap/include/plat/serial.h |    2 +-
 3 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
index 207905d..85a21e7 100644
--- a/arch/arm/mach-omap2/pm34xx.c
+++ b/arch/arm/mach-omap2/pm34xx.c
@@ -418,7 +418,7 @@ void omap_sram_idle(void)
                        } else
                                omap3_per_save_context();
                }
-               omap_uart_prepare_idle(2);
+               omap_uart_prepare_idle(2, per_next_state);
        }
 
        if (pwrdm_read_pwrst(cam_pwrdm) == PWRDM_POWER_ON)
@@ -426,8 +426,8 @@ void omap_sram_idle(void)
 
        /* CORE */
        if (core_next_state < PWRDM_POWER_ON) {
-               omap_uart_prepare_idle(0);
-               omap_uart_prepare_idle(1);
+               omap_uart_prepare_idle(0, core_next_state);
+               omap_uart_prepare_idle(1, core_next_state);
                if (core_next_state == PWRDM_POWER_OFF) {
                        omap3_core_save_context();
                        omap3_prcm_save_context();
diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index d545eed..85e09ef 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -185,9 +185,6 @@ static void omap_uart_save_context(struct omap_uart_state 
*uart)
        u16 lcr = 0;
        struct plat_serial8250_port *p = uart->p;
 
-       if (!enable_off_mode)
-               return;
-
        lcr = serial_read_reg(p, UART_LCR);
        serial_write_reg(p, UART_LCR, 0xBF);
        uart->dll = serial_read_reg(p, UART_DLL);
@@ -206,9 +203,6 @@ static void omap_uart_restore_context(struct 
omap_uart_state *uart)
        u16 efr = 0;
        struct plat_serial8250_port *p = uart->p;
 
-       if (!enable_off_mode)
-               return;
-
        if (!uart->context_valid)
                return;
 
@@ -252,12 +246,24 @@ static inline void omap_uart_enable_clocks(struct 
omap_uart_state *uart)
 
 #ifdef CONFIG_PM
 
-static inline void omap_uart_disable_clocks(struct omap_uart_state *uart)
+static inline void omap_uart_disable_clocks(struct omap_uart_state *uart,
+                                               int power_state)
 {
        if (!uart->clocked)
                return;
 
-       omap_uart_save_context(uart);
+       if (power_state == PWRDM_POWER_OFF) {
+               if (uart->context_valid)
+                       return;
+               if (!uart->clocked) {
+                       clk_enable(uart->ick);
+                       clk_enable(uart->fck);
+               }
+               omap_uart_save_context(uart);
+       } else if (!uart->clocked) {
+               return;
+       }
+
        uart->clocked = 0;
        clk_disable(uart->ick);
        clk_disable(uart->fck);
@@ -347,13 +353,13 @@ static void omap_uart_idle_timer(unsigned long data)
        omap_uart_allow_sleep(uart);
 }
 
-void omap_uart_prepare_idle(int num)
+void omap_uart_prepare_idle(int num, int power_state)
 {
        struct omap_uart_state *uart;
 
        list_for_each_entry(uart, &uart_list, node) {
                if (num == uart->num && uart->can_sleep) {
-                       omap_uart_disable_clocks(uart);
+                       omap_uart_disable_clocks(uart, power_state);
                        return;
                }
        }
diff --git a/arch/arm/plat-omap/include/plat/serial.h 
b/arch/arm/plat-omap/include/plat/serial.h
index 19145f5..71ca2da 100644
--- a/arch/arm/plat-omap/include/plat/serial.h
+++ b/arch/arm/plat-omap/include/plat/serial.h
@@ -99,7 +99,7 @@ extern void omap_serial_init_port(int port);
 extern int omap_uart_can_sleep(void);
 extern void omap_uart_check_wakeup(void);
 extern void omap_uart_prepare_suspend(void);
-extern void omap_uart_prepare_idle(int num);
+extern void omap_uart_prepare_idle(int num, int power_state);
 extern void omap_uart_resume_idle(int num);
 extern void omap_uart_enable_irqs(int enable);
 #endif
-- 
1.5.4.3

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