From: Tero Kristo <tero.kristo@xxxxxxxxx>
This patch contains following improvements:
- Only RX interrupt will now kick the sleep prevent timer
- TX fifo status is checked before disabling clocks, this will prevent
on-going transmission to be cut
- Smartidle is now enabled/disabled only while switching clocks, as having
smartidle enabled while RX/TX prevents any wakeups from being received
from UART module
- Added workqueue for wakeup checks, as jiffy timer access within the
idle loop results into skewed timers as jiffy timers are stopped
- Added garbage_timer for ignoring the first character received during
the first tick after clock enable, this prevents garbage characters to be
received in low sleep states
- omap_uart_enable_irqs() changed to use enable_irq / disable_irq instead
of request / free. Using request/free changes the behavior after first
suspend due to reversed interrupt handler ordering
Signed-off-by: Tero Kristo <tero.kristo@xxxxxxxxx>
---
arch/arm/mach-omap2/serial.c | 67 +++++++++++++++++++++++++++++++++++-------
1 files changed, 56 insertions(+), 11 deletions(-)
diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index 5f3035e..06d18f5 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -23,6 +23,7 @@
#include <linux/serial_reg.h>
#include <linux/clk.h>
#include <linux/io.h>
+#include <linux/workqueue.h>
#include <plat/common.h>
#include <plat/board.h>
@@ -48,7 +49,10 @@ struct omap_uart_state {
int num;
int can_sleep;
struct timer_list timer;
+ struct timer_list garbage_timer;
+ struct work_struct wakeup_work;
u32 timeout;
+ u8 garbage_ignore;
void __iomem *wk_st;
void __iomem *wk_en;
@@ -243,6 +247,11 @@ static inline void omap_uart_save_context(struct omap_uart_state *uart) {}
static inline void omap_uart_restore_context(struct omap_uart_state *uart) {}
#endif /* CONFIG_PM && CONFIG_ARCH_OMAP3 */
+#ifdef CONFIG_PM
+static void omap_uart_smart_idle_enable(struct omap_uart_state *uart,
+ int enable);
+#endif
+
static inline void omap_uart_enable_clocks(struct omap_uart_state *uart)
{
if (uart->clocked)
@@ -252,6 +261,15 @@ static inline void omap_uart_enable_clocks(struct omap_uart_state *uart)
clk_enable(uart->fck);
uart->clocked = 1;
omap_uart_restore_context(uart);
+#ifdef CONFIG_PM
+ omap_uart_smart_idle_enable(uart, 0);
+#endif
+
+ /* Set up garbage timer to ignore RX during first jiffy */
+ if (uart->timeout) {
+ mod_timer(&uart->garbage_timer, jiffies + 1);
+ uart->garbage_ignore = 1;
+ }
}
#ifdef CONFIG_PM
@@ -263,6 +281,7 @@ static inline void omap_uart_disable_clocks(struct omap_uart_state *uart)
omap_uart_save_context(uart);
uart->clocked = 0;
+ omap_uart_smart_idle_enable(uart, 1);
clk_disable(uart->ick);
clk_disable(uart->fck);
}
@@ -320,7 +339,6 @@ static void omap_uart_block_sleep(struct omap_uart_state *uart)
{
omap_uart_enable_clocks(uart);
- omap_uart_smart_idle_enable(uart, 0);
uart->can_sleep = 0;
if (uart->timeout)
mod_timer(&uart->timer, jiffies + uart->timeout);
@@ -338,7 +356,6 @@ static void omap_uart_allow_sleep(struct omap_uart_state *uart)
if (!uart->clocked)
return;
- omap_uart_smart_idle_enable(uart, 1);
uart->can_sleep = 1;
del_timer(&uart->timer);
}
@@ -350,13 +367,30 @@ static void omap_uart_idle_timer(unsigned long data)
omap_uart_allow_sleep(uart);
}
+static void omap_uart_garbage_timer(unsigned long data)
+{
+ struct omap_uart_state *uart = (struct omap_uart_state *)data;
+
+ uart->garbage_ignore = 0;
+}
+
+static void omap_uart_wakeup_work(struct work_struct *work)
+{
+ struct omap_uart_state *uart =
+ container_of(work, struct omap_uart_state, wakeup_work);
+
+ omap_uart_block_sleep(uart);
+}
+
void omap_uart_prepare_idle(int num)
{
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);
+ if (serial_read_reg(uart->p, UART_LSR) &
+ UART_LSR_TEMT)
+ omap_uart_disable_clocks(uart);
return;
}
}
@@ -375,12 +409,12 @@ void omap_uart_resume_idle(int num)
u16 p = omap_ctrl_readw(uart->padconf);
if (p & OMAP3_PADCONF_WAKEUPEVENT0)
- omap_uart_block_sleep(uart);
+ schedule_work(&uart->wakeup_work);
}
/* Check for normal UART wakeup */
if (__raw_readl(uart->wk_st) & uart->wk_mask)
- omap_uart_block_sleep(uart);
+ schedule_work(&uart->wakeup_work);
return;
}
}
@@ -428,8 +462,18 @@ int omap_uart_can_sleep(void)
static irqreturn_t omap_uart_interrupt(int irq, void *dev_id)
{
struct omap_uart_state *uart = dev_id;
+ u8 lsr;
- omap_uart_block_sleep(uart);
+ lsr = serial_read_reg(uart->p, UART_LSR);
+ /* Check for receive interrupt */
+ if (lsr & UART_LSR_DR) {
+ omap_uart_block_sleep(uart);
+ if (uart->garbage_ignore) {
+ del_timer(&uart->garbage_timer);
+ uart->garbage_ignore = 0;
+ serial_read_reg(uart->p, UART_RX);
+ }
+ }
return IRQ_NONE;
}
@@ -443,6 +487,9 @@ static void omap_uart_idle_init(struct omap_uart_state *uart)
uart->timeout = DEFAULT_TIMEOUT;
setup_timer(&uart->timer, omap_uart_idle_timer,
(unsigned long) uart);
+ setup_timer(&uart->garbage_timer, omap_uart_garbage_timer,
+ (unsigned long) uart);
+ INIT_WORK(&uart->wakeup_work, omap_uart_wakeup_work);
if (uart->timeout)
mod_timer(&uart->timer, jiffies + uart->timeout);
omap_uart_smart_idle_enable(uart, 0);
@@ -507,15 +554,13 @@ static void omap_uart_idle_init(struct omap_uart_state *uart)
void omap_uart_enable_irqs(int enable)
{
- int ret;
struct omap_uart_state *uart;
list_for_each_entry(uart, &uart_list, node) {
if (enable)
- ret = request_irq(uart->p->irq, omap_uart_interrupt,
- IRQF_SHARED, "serial idle", (void *)uart);
+ enable_irq(uart->p->irq);
else
- free_irq(uart->p->irq, (void *)uart);
+ disable_irq(uart->p->irq);
}
}
--
1.5.4.3
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