[PATCH PM-20081106] OMAP3: UART: Make sure that uart clocks are enabled when needed

[Jouni Hogander]

Current implementation makes it possible that printouts are
written into UART while its clocks are disabled. This causes freeze.

This patch contains possible fix for this.

Signed-off-by: Jouni Hogander <[EMAIL PROTECTED]>
---
 arch/arm/mach-omap2/pm34xx.c             |    6 ++++++
 arch/arm/mach-omap2/serial.c             |   30 ++++++++++++++++++++++++++++++
 arch/arm/plat-omap/include/mach/serial.h |    2 ++
 3 files changed, 38 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
index d480c39..3838a19 100644
--- a/arch/arm/mach-omap2/pm34xx.c
+++ b/arch/arm/mach-omap2/pm34xx.c
@@ -320,6 +320,7 @@ void omap_sram_idle(void)
        /* PER */
        per_next_state = pwrdm_read_next_pwrst(per_pwrdm);
        if (per_next_state < PWRDM_POWER_ON) {
+               omap_uart_prepare_idle(2);
                omap2_gpio_prepare_for_retention();
                if (per_next_state == PWRDM_POWER_OFF)
                        omap3_per_save_context();
@@ -328,6 +329,8 @@ void omap_sram_idle(void)
        /* CORE */
        core_next_state = pwrdm_read_next_pwrst(core_pwrdm);
        if (core_next_state < PWRDM_POWER_ON) {
+               omap_uart_prepare_idle(0);
+               omap_uart_prepare_idle(1);
                if (core_next_state == PWRDM_POWER_OFF) {
                        prm_set_mod_reg_bits(OMAP3430_AUTO_OFF,
                                             OMAP3430_GR_MOD,
@@ -386,6 +389,8 @@ void omap_sram_idle(void)
                        prm_clear_mod_reg_bits(OMAP3430_AUTO_OFF,
                                               OMAP3430_GR_MOD,
                                               OMAP3_PRM_VOLTCTRL_OFFSET);
+               omap_uart_resume_idle(0);
+               omap_uart_resume_idle(1);
        }
 
        /* PER */
@@ -394,6 +399,7 @@ void omap_sram_idle(void)
                if (per_prev_state == PWRDM_POWER_OFF)
                        omap3_per_restore_context();
                omap2_gpio_resume_after_retention();
+               omap_uart_resume_idle(2);
        }
 
        /* Enable smartreflex after WFI */
diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index 65cce87..ef30d8d 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -249,6 +249,36 @@ static void omap_uart_idle_timer(unsigned long data)
        omap_uart_allow_sleep(uart);
 }
 
+void omap_uart_prepare_idle(int num)
+{
+       struct omap_uart_state *uart;
+
+       if (!clocks_off_while_idle)
+               return;
+
+       list_for_each_entry(uart, &uart_list, node) {
+               if (num == uart->num && uart->can_sleep) {
+                       omap_uart_disable_clocks(uart);
+                       return;
+               }
+       }
+}
+
+void omap_uart_resume_idle(int num)
+{
+       struct omap_uart_state *uart;
+
+       if (!clocks_off_while_idle)
+               return;
+
+       list_for_each_entry(uart, &uart_list, node) {
+               if (num == uart->num) {
+                       omap_uart_enable_clocks(uart);
+                       return;
+               }
+       }
+}
+
 void omap_uart_check_wakeup(void)
 {
        struct omap_uart_state *uart;
diff --git a/arch/arm/plat-omap/include/mach/serial.h 
b/arch/arm/plat-omap/include/mach/serial.h
index 11ff540..254a775 100644
--- a/arch/arm/plat-omap/include/mach/serial.h
+++ b/arch/arm/plat-omap/include/mach/serial.h
@@ -44,6 +44,8 @@
 extern void omap_serial_init(void);
 extern int omap_uart_can_sleep(void);
 extern void omap_uart_check_wakeup(void);
+extern void omap_uart_prepare_idle(int num);
+extern void omap_uart_resume_idle(int num);
 #endif
 
 #endif
-- 
1.6.0.1

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