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

[Jouni Hogander <jouni.hogander@xxxxxxxxx>]

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 <jouni.hogander@xxxxxxxxx>
---
 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

--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html