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
- Sleep prevent timer is changed to use ktime_get() instead of a jiffy timer
as jiffy timers are not valid within idle loop (tick scheduler is stopped)
- Added RX ignore timer for ignoring the first character received during
first millisecond of wakeup, this prevents garbage character to be receive
in low sleep states
Signed-off-by: Tero Kristo <tero.kristo@xxxxxxxxx>
---
arch/arm/mach-omap2/serial.c | 79 +++++++++++++++++++++++++++--------------
1 files changed, 52 insertions(+), 27 deletions(-)
diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index 5f3035e..4be9ace 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -29,6 +29,8 @@
#include <plat/clock.h>
#include <plat/control.h>
+#include <asm/div64.h>
+
#include "prm.h"
#include "pm.h"
#include "prm-regbits-34xx.h"
@@ -42,13 +44,14 @@
* disabled via sysfs. This also causes that any deeper omap sleep states are
* blocked.
*/
-#define DEFAULT_TIMEOUT 0
+#define DEFAULT_TIMEOUT (0LL * NSEC_PER_SEC)
struct omap_uart_state {
int num;
int can_sleep;
- struct timer_list timer;
- u32 timeout;
+ ktime_t expire_time;
+ ktime_t garbage_time;
+ u64 timeout;
void __iomem *wk_st;
void __iomem *wk_en;
@@ -243,6 +246,9 @@ 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 */
+static void omap_uart_smart_idle_enable(struct omap_uart_state *uart,
+ int enable);
+
static inline void omap_uart_enable_clocks(struct omap_uart_state *uart)
{
if (uart->clocked)
@@ -250,8 +256,12 @@ static inline void omap_uart_enable_clocks(struct omap_uart_state *uart)
clk_enable(uart->ick);
clk_enable(uart->fck);
+ omap_uart_smart_idle_enable(uart, 0);
uart->clocked = 1;
omap_uart_restore_context(uart);
+
+ /* Set up garbage timer to ignore RX during first 1ms */
+ uart->garbage_time = ktime_add_ns(ktime_get(), NSEC_PER_MSEC);
}
#ifdef CONFIG_PM
@@ -263,6 +273,7 @@ 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);
}
@@ -320,12 +331,9 @@ 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);
- else
- del_timer(&uart->timer);
+ uart->expire_time = ktime_add_ns(ktime_get(), uart->timeout);
}
static void omap_uart_allow_sleep(struct omap_uart_state *uart)
@@ -338,16 +346,7 @@ 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);
-}
-
-static void omap_uart_idle_timer(unsigned long data)
-{
- struct omap_uart_state *uart = (struct omap_uart_state *)data;
-
- omap_uart_allow_sleep(uart);
}
void omap_uart_prepare_idle(int num)
@@ -355,8 +354,14 @@ 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 && uart->timeout)
+ if (ktime_get().tv64 > uart->expire_time.tv64)
+ uart->can_sleep = 1;
+
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;
}
}
@@ -404,6 +409,10 @@ int omap_uart_can_sleep(void)
if (!uart->clocked)
continue;
+ if (!uart->can_sleep && uart->timeout &&
+ ktime_get().tv64 > uart->expire_time.tv64)
+ uart->can_sleep = 1;
+
if (!uart->can_sleep) {
can_sleep = 0;
continue;
@@ -428,10 +437,22 @@ 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;
+ int ret = IRQ_NONE;
- 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_time.tv64 &&
+ ktime_get().tv64 < uart->garbage_time.tv64) {
+ serial_read_reg(uart->p, UART_RX);
+ uart->garbage_time.tv64 = 0;
+ ret = IRQ_HANDLED;
+ }
+ }
- return IRQ_NONE;
+ return ret;
}
static void omap_uart_idle_init(struct omap_uart_state *uart)
@@ -441,10 +462,8 @@ static void omap_uart_idle_init(struct omap_uart_state *uart)
uart->can_sleep = 0;
uart->timeout = DEFAULT_TIMEOUT;
- setup_timer(&uart->timer, omap_uart_idle_timer,
- (unsigned long) uart);
if (uart->timeout)
- mod_timer(&uart->timer, jiffies + uart->timeout);
+ uart->expire_time = ktime_add_ns(ktime_get(), uart->timeout);
omap_uart_smart_idle_enable(uart, 0);
if (cpu_is_omap34xx()) {
@@ -527,8 +546,12 @@ static ssize_t sleep_timeout_show(struct device *dev,
struct platform_device, dev);
struct omap_uart_state *uart = container_of(pdev,
struct omap_uart_state, pdev);
+ u64 val;
+
+ val = uart->timeout;
- return sprintf(buf, "%u\n", uart->timeout / HZ);
+ do_div(val, NSEC_PER_SEC);
+ return sprintf(buf, "%llu\n", val);
}
static ssize_t sleep_timeout_store(struct device *dev,
@@ -546,10 +569,12 @@ static ssize_t sleep_timeout_store(struct device *dev,
return -EINVAL;
}
- uart->timeout = value * HZ;
- if (uart->timeout)
- mod_timer(&uart->timer, jiffies + uart->timeout);
- else
+ uart->timeout = (u64)value * NSEC_PER_SEC;
+ if (uart->timeout) {
+ uart->expire_time = ktime_get();
+ uart->expire_time =
+ ktime_add_ns(uart->expire_time, uart->timeout);
+ } else
/* A zero value means disable timeout feature */
omap_uart_block_sleep(uart);
--
1.5.4.3
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