RE: [PATCH] OMAP3: Serial: Improved sleep logic
This patch can be ignored. The RX fifo clear logic did not really work for low
C states (C1 / C2) and you would still get garbage. I'll send an updated patch
where I have replaced the logic by an ignore timer for the first millisecond
after clocks are enabled. Also, I forgot v2 out from this.
-Original Message-
From: linux-omap-ow...@vger.kernel.org
[mailto:linux-omap-ow...@vger.kernel.org] On Behalf Of Kristo
Tero (Nokia-D/Tampere)
Sent: 10 February, 2010 18:29
To: linux-omap@vger.kernel.org
Subject: [PATCH] OMAP3: Serial: Improved sleep logic
From: Tero Kristo tero.kri...@nokia.com
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 disabled while entering idle if we have data in
the transmit
buffer because having this enabled would prevent wakeups from the TX
interrupt and this would cause pauses while sending large
blocks of data
- 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)
- RX and TX fifos are cleared when clocks are enabled, this
will purge the
first character from RX fifo, which is most likely garbage
Signed-off-by: Tero Kristo tero.kri...@nokia.com
---
arch/arm/mach-omap2/serial.c | 70
+++---
1 files changed, 45 insertions(+), 25 deletions(-)
diff --git a/arch/arm/mach-omap2/serial.c
b/arch/arm/mach-omap2/serial.c
index 837b347..d7d96ba 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -23,12 +23,15 @@
#include linux/serial_reg.h
#include linux/clk.h
#include linux/io.h
+#include linux/delay.h
#include plat/common.h
#include plat/board.h
#include plat/clock.h
#include plat/control.h
+#include asm/div64.h
+
#include prm.h
#include pm.h
#include prm-regbits-34xx.h
@@ -36,13 +39,13 @@
#define UART_OMAP_NO_EMPTY_FIFO_READ_IP_REV 0x52
#define UART_OMAP_WER 0x17/* Wake-up enable register */
-#define DEFAULT_TIMEOUT (5 * HZ)
+#define DEFAULT_TIMEOUT (5LL * NSEC_PER_SEC)
struct omap_uart_state {
int num;
int can_sleep;
- struct timer_list timer;
- u32 timeout;
+ ktime_t expire_time;
+ u64 timeout;
void __iomem *wk_st;
void __iomem *wk_en;
@@ -231,6 +234,9 @@ static inline void
omap_uart_enable_clocks(struct omap_uart_state *uart)
clk_enable(uart-fck);
uart-clocked = 1;
omap_uart_restore_context(uart);
+
+ /* Clear RX and TX fifos, as they contain garbage at
this point */
+ serial_write_reg(uart-p, UART_FCR, 0xa7);
}
#ifdef CONFIG_PM
@@ -302,9 +308,7 @@ static void omap_uart_block_sleep(struct
omap_uart_state *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)
@@ -317,25 +321,28 @@ static void omap_uart_allow_sleep(struct
omap_uart_state *uart)
if (!uart-clocked)
return;
- omap_uart_smart_idle_enable(uart, 1);
+ if (serial_read_reg(uart-p, UART_LSR) UART_LSR_TEMT)
+ 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)
{
struct omap_uart_state *uart;
+ ktime_t t;
list_for_each_entry(uart, uart_list, node) {
+ if (num == uart-num !uart-can_sleep) {
+ t = ktime_get();
+ if (t.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);
+ else
+ omap_uart_smart_idle_enable(uart, 0);
return;
}
}
@@ -360,6 +367,7 @@ void omap_uart_resume_idle(int num)
/* Check for normal UART wakeup */
if (__raw_readl(uart-wk_st) uart-wk_mask)
omap_uart_block_sleep(uart);
+
return;
}
}
@@ -407,8 +415,14 @@ int omap_uart_can_sleep(void)
static irqreturn_t omap_uart_interrupt(int irq, void *dev_id)
{
struct
[PATCH] OMAP3: Serial: Improved sleep logic
From: Tero Kristo tero.kri...@nokia.com
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 disabled while entering idle if we have data in the transmit
buffer because having this enabled would prevent wakeups from the TX
interrupt and this would cause pauses while sending large blocks of data
- 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)
- RX and TX fifos are cleared when clocks are enabled, this will purge the
first character from RX fifo, which is most likely garbage
Signed-off-by: Tero Kristo tero.kri...@nokia.com
---
arch/arm/mach-omap2/serial.c | 70 +++---
1 files changed, 45 insertions(+), 25 deletions(-)
diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index 837b347..d7d96ba 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -23,12 +23,15 @@
#include linux/serial_reg.h
#include linux/clk.h
#include linux/io.h
+#include linux/delay.h
#include plat/common.h
#include plat/board.h
#include plat/clock.h
#include plat/control.h
+#include asm/div64.h
+
#include prm.h
#include pm.h
#include prm-regbits-34xx.h
@@ -36,13 +39,13 @@
#define UART_OMAP_NO_EMPTY_FIFO_READ_IP_REV0x52
#define UART_OMAP_WER 0x17/* Wake-up enable register */
-#define DEFAULT_TIMEOUT (5 * HZ)
+#define DEFAULT_TIMEOUT (5LL * NSEC_PER_SEC)
struct omap_uart_state {
int num;
int can_sleep;
- struct timer_list timer;
- u32 timeout;
+ ktime_t expire_time;
+ u64 timeout;
void __iomem *wk_st;
void __iomem *wk_en;
@@ -231,6 +234,9 @@ static inline void omap_uart_enable_clocks(struct
omap_uart_state *uart)
clk_enable(uart-fck);
uart-clocked = 1;
omap_uart_restore_context(uart);
+
+ /* Clear RX and TX fifos, as they contain garbage at this point */
+ serial_write_reg(uart-p, UART_FCR, 0xa7);
}
#ifdef CONFIG_PM
@@ -302,9 +308,7 @@ static void omap_uart_block_sleep(struct omap_uart_state
*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)
@@ -317,25 +321,28 @@ static void omap_uart_allow_sleep(struct omap_uart_state
*uart)
if (!uart-clocked)
return;
- omap_uart_smart_idle_enable(uart, 1);
+ if (serial_read_reg(uart-p, UART_LSR) UART_LSR_TEMT)
+ 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)
{
struct omap_uart_state *uart;
+ ktime_t t;
list_for_each_entry(uart, uart_list, node) {
+ if (num == uart-num !uart-can_sleep) {
+ t = ktime_get();
+ if (t.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);
+ else
+ omap_uart_smart_idle_enable(uart, 0);
return;
}
}
@@ -360,6 +367,7 @@ void omap_uart_resume_idle(int num)
/* Check for normal UART wakeup */
if (__raw_readl(uart-wk_st) uart-wk_mask)
omap_uart_block_sleep(uart);
+
return;
}
}
@@ -407,8 +415,14 @@ 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 (lsr UART_LSR_TEMT uart-can_sleep)
+ omap_uart_smart_idle_enable(uart, 1);
return IRQ_NONE;
}
@@ -420,9 +434,9 @@ static void omap_uart_idle_init(struct omap_uart_state
*uart)
uart-can_sleep = 0;
uart-timeout =
RE: [PATCH] OMAP3: Serial: Improved sleep logic
-Original Message-
From: ext Tony Lindgren [mailto:t...@atomide.com]
Sent: 04 February, 2010 18:11
To: Kristo Tero (Nokia-D/Tampere)
Cc: linux-omap@vger.kernel.org
Subject: Re: [PATCH] OMAP3: Serial: Improved sleep logic
* tero.kri...@nokia.com tero.kri...@nokia.com [100203 23:59]:
-Original Message-
From: ext Tony Lindgren [mailto:t...@atomide.com]
Sent: 03 February, 2010 19:50
To: Kristo Tero (Nokia-D/Tampere)
Cc: linux-omap@vger.kernel.org
Subject: Re: [PATCH] OMAP3: Serial: Improved sleep logic
* Tero Kristo tero.kri...@nokia.com [100202 01:38]:
From: Tero Kristo tero.kri...@nokia.com
Only RX interrupt will now kick the sleep prevent timer. In
addition, TX
fifo status is checked before disabling clocks, this will
prevent occasional
garbage being printed on serial line. Smartidle is also
disabled while
entering idle if we have data in the transmit buffer,
because having this
enabled will prevent wakeups from the TX interrupt, and
this causes
pauses while sending large blocks of data.
Sounds this is for 2.6.34 merge window and does not contain anything
that needs to be fixed for 2.6.33.
Yeah, this only fixes a couple of annoying issues, but
nothing fatal. Also improves power efficiency in some cases
which is a nice to have feature, and basically eases the
development of PM code as the UART does not block the system
from sleeping always.
Yeah cool. Separate issue, but I wonder if we should also clear
the the first rx character from the fifo to avoid corrupting
the console. Only when the uart clocks are off and and
we get a key press. Would be easy to do just do with one
serial_read_reg(uart-p, UART_RX)..
Yeah, I can try to add this change to the code and see what happens.
Tony
-Tero
Regards,
Tony
Signed-off-by: Tero Kristo tero.kri...@nokia.com
---
arch/arm/mach-omap2/serial.c | 19 +++
1 files changed, 15 insertions(+), 4 deletions(-)
diff --git a/arch/arm/mach-omap2/serial.c
b/arch/arm/mach-omap2/serial.c
index 777e802..e11dfe9 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -317,7 +317,8 @@ static void omap_uart_allow_sleep(struct
omap_uart_state *uart)
if (!uart-clocked)
return;
- omap_uart_smart_idle_enable(uart, 1);
+ if (serial_read_reg(uart-p, UART_LSR) UART_LSR_TEMT)
+ omap_uart_smart_idle_enable(uart, 1);
uart-can_sleep = 1;
del_timer(uart-timer);
}
@@ -335,7 +336,11 @@ void omap_uart_prepare_idle(int num)
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);
+ else
+ omap_uart_smart_idle_enable(uart, 0);
return;
}
}
@@ -407,8 +412,14 @@ 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 (lsr UART_LSR_TEMT uart-can_sleep)
+ omap_uart_smart_idle_enable(uart, 1);
return IRQ_NONE;
}
--
1.5.4.3
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RE: [PATCH] OMAP3: Serial: Improved sleep logic
-Original Message-
From: ext Tony Lindgren [mailto:t...@atomide.com]
Sent: 03 February, 2010 19:50
To: Kristo Tero (Nokia-D/Tampere)
Cc: linux-omap@vger.kernel.org
Subject: Re: [PATCH] OMAP3: Serial: Improved sleep logic
* Tero Kristo tero.kri...@nokia.com [100202 01:38]:
From: Tero Kristo tero.kri...@nokia.com
Only RX interrupt will now kick the sleep prevent timer. In
addition, TX
fifo status is checked before disabling clocks, this will
prevent occasional
garbage being printed on serial line. Smartidle is also
disabled while
entering idle if we have data in the transmit buffer,
because having this
enabled will prevent wakeups from the TX interrupt, and this causes
pauses while sending large blocks of data.
Sounds this is for 2.6.34 merge window and does not contain anything
that needs to be fixed for 2.6.33.
Yeah, this only fixes a couple of annoying issues, but nothing fatal. Also
improves power efficiency in some cases which is a nice to have feature, and
basically eases the development of PM code as the UART does not block the
system from sleeping always.
-Tero
Regards,
Tony
Signed-off-by: Tero Kristo tero.kri...@nokia.com
---
arch/arm/mach-omap2/serial.c | 19 +++
1 files changed, 15 insertions(+), 4 deletions(-)
diff --git a/arch/arm/mach-omap2/serial.c
b/arch/arm/mach-omap2/serial.c
index 777e802..e11dfe9 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -317,7 +317,8 @@ static void omap_uart_allow_sleep(struct
omap_uart_state *uart)
if (!uart-clocked)
return;
-omap_uart_smart_idle_enable(uart, 1);
+if (serial_read_reg(uart-p, UART_LSR) UART_LSR_TEMT)
+omap_uart_smart_idle_enable(uart, 1);
uart-can_sleep = 1;
del_timer(uart-timer);
}
@@ -335,7 +336,11 @@ void omap_uart_prepare_idle(int num)
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);
+else
+omap_uart_smart_idle_enable(uart, 0);
return;
}
}
@@ -407,8 +412,14 @@ 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 (lsr UART_LSR_TEMT uart-can_sleep)
+omap_uart_smart_idle_enable(uart, 1);
return IRQ_NONE;
}
--
1.5.4.3
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Re: [PATCH] OMAP3: Serial: Improved sleep logic
* tero.kri...@nokia.com tero.kri...@nokia.com [100203 23:59]:
-Original Message-
From: ext Tony Lindgren [mailto:t...@atomide.com]
Sent: 03 February, 2010 19:50
To: Kristo Tero (Nokia-D/Tampere)
Cc: linux-omap@vger.kernel.org
Subject: Re: [PATCH] OMAP3: Serial: Improved sleep logic
* Tero Kristo tero.kri...@nokia.com [100202 01:38]:
From: Tero Kristo tero.kri...@nokia.com
Only RX interrupt will now kick the sleep prevent timer. In
addition, TX
fifo status is checked before disabling clocks, this will
prevent occasional
garbage being printed on serial line. Smartidle is also
disabled while
entering idle if we have data in the transmit buffer,
because having this
enabled will prevent wakeups from the TX interrupt, and this causes
pauses while sending large blocks of data.
Sounds this is for 2.6.34 merge window and does not contain anything
that needs to be fixed for 2.6.33.
Yeah, this only fixes a couple of annoying issues, but nothing fatal. Also
improves power efficiency in some cases which is a nice to have feature, and
basically eases the development of PM code as the UART does not block the
system from sleeping always.
Yeah cool. Separate issue, but I wonder if we should also clear
the the first rx character from the fifo to avoid corrupting
the console. Only when the uart clocks are off and and
we get a key press. Would be easy to do just do with one
serial_read_reg(uart-p, UART_RX)..
Tony
-Tero
Regards,
Tony
Signed-off-by: Tero Kristo tero.kri...@nokia.com
---
arch/arm/mach-omap2/serial.c | 19 +++
1 files changed, 15 insertions(+), 4 deletions(-)
diff --git a/arch/arm/mach-omap2/serial.c
b/arch/arm/mach-omap2/serial.c
index 777e802..e11dfe9 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -317,7 +317,8 @@ static void omap_uart_allow_sleep(struct
omap_uart_state *uart)
if (!uart-clocked)
return;
- omap_uart_smart_idle_enable(uart, 1);
+ if (serial_read_reg(uart-p, UART_LSR) UART_LSR_TEMT)
+ omap_uart_smart_idle_enable(uart, 1);
uart-can_sleep = 1;
del_timer(uart-timer);
}
@@ -335,7 +336,11 @@ void omap_uart_prepare_idle(int num)
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);
+ else
+ omap_uart_smart_idle_enable(uart, 0);
return;
}
}
@@ -407,8 +412,14 @@ 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 (lsr UART_LSR_TEMT uart-can_sleep)
+ omap_uart_smart_idle_enable(uart, 1);
return IRQ_NONE;
}
--
1.5.4.3
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Re: [PATCH] OMAP3: Serial: Improved sleep logic
Tero Kristo tero.kri...@nokia.com writes:
From: Tero Kristo tero.kri...@nokia.com
Only RX interrupt will now kick the sleep prevent timer. In addition, TX
fifo status is checked before disabling clocks, this will prevent occasional
garbage being printed on serial line. Smartidle is also disabled while
entering idle if we have data in the transmit buffer, because having this
enabled will prevent wakeups from the TX interrupt, and this causes
pauses while sending large blocks of data.
Signed-off-by: Tero Kristo tero.kri...@nokia.com
After doing some more testing with this, something is not quite right
still. I haven't taken the time to debug further, but with this patch
on top of the current PM branch, the timer seems to expire and disable
clocks whether or not there is UART activity.
In particular, using a UART1 console on OMAP3EVM, I notice that while
typing longer commands (that take more that timeout seconds to type),
I notice that I loose chars in the middle of typing. /me doesn't like.
So I won't be applying this to the PM branch until we can figure out
what's happening here.
Kevin
---
arch/arm/mach-omap2/serial.c | 19 +++
1 files changed, 15 insertions(+), 4 deletions(-)
diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index 777e802..e11dfe9 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -317,7 +317,8 @@ static void omap_uart_allow_sleep(struct omap_uart_state
*uart)
if (!uart-clocked)
return;
- omap_uart_smart_idle_enable(uart, 1);
+ if (serial_read_reg(uart-p, UART_LSR) UART_LSR_TEMT)
+ omap_uart_smart_idle_enable(uart, 1);
uart-can_sleep = 1;
del_timer(uart-timer);
}
@@ -335,7 +336,11 @@ void omap_uart_prepare_idle(int num)
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);
+ else
+ omap_uart_smart_idle_enable(uart, 0);
return;
}
}
@@ -407,8 +412,14 @@ 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 (lsr UART_LSR_TEMT uart-can_sleep)
+ omap_uart_smart_idle_enable(uart, 1);
return IRQ_NONE;
}
--
1.5.4.3
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Re: [PATCH] OMAP3: Serial: Improved sleep logic
* Tero Kristo tero.kri...@nokia.com [100202 01:38]:
From: Tero Kristo tero.kri...@nokia.com
Only RX interrupt will now kick the sleep prevent timer. In addition, TX
fifo status is checked before disabling clocks, this will prevent occasional
garbage being printed on serial line. Smartidle is also disabled while
entering idle if we have data in the transmit buffer, because having this
enabled will prevent wakeups from the TX interrupt, and this causes
pauses while sending large blocks of data.
Sounds this is for 2.6.34 merge window and does not contain anything
that needs to be fixed for 2.6.33.
Regards,
Tony
Signed-off-by: Tero Kristo tero.kri...@nokia.com
---
arch/arm/mach-omap2/serial.c | 19 +++
1 files changed, 15 insertions(+), 4 deletions(-)
diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index 777e802..e11dfe9 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -317,7 +317,8 @@ static void omap_uart_allow_sleep(struct omap_uart_state
*uart)
if (!uart-clocked)
return;
- omap_uart_smart_idle_enable(uart, 1);
+ if (serial_read_reg(uart-p, UART_LSR) UART_LSR_TEMT)
+ omap_uart_smart_idle_enable(uart, 1);
uart-can_sleep = 1;
del_timer(uart-timer);
}
@@ -335,7 +336,11 @@ void omap_uart_prepare_idle(int num)
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);
+ else
+ omap_uart_smart_idle_enable(uart, 0);
return;
}
}
@@ -407,8 +412,14 @@ 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 (lsr UART_LSR_TEMT uart-can_sleep)
+ omap_uart_smart_idle_enable(uart, 1);
return IRQ_NONE;
}
--
1.5.4.3
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[PATCH] OMAP3: Serial: Improved sleep logic
From: Tero Kristo tero.kri...@nokia.com
Only RX interrupt will now kick the sleep prevent timer. In addition, TX
fifo status is checked before disabling clocks, this will prevent occasional
garbage being printed on serial line. Smartidle is also disabled while
entering idle if we have data in the transmit buffer, because having this
enabled will prevent wakeups from the TX interrupt, and this causes
pauses while sending large blocks of data.
Signed-off-by: Tero Kristo tero.kri...@nokia.com
---
arch/arm/mach-omap2/serial.c | 19 +++
1 files changed, 15 insertions(+), 4 deletions(-)
diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index 777e802..e11dfe9 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -317,7 +317,8 @@ static void omap_uart_allow_sleep(struct omap_uart_state
*uart)
if (!uart-clocked)
return;
- omap_uart_smart_idle_enable(uart, 1);
+ if (serial_read_reg(uart-p, UART_LSR) UART_LSR_TEMT)
+ omap_uart_smart_idle_enable(uart, 1);
uart-can_sleep = 1;
del_timer(uart-timer);
}
@@ -335,7 +336,11 @@ void omap_uart_prepare_idle(int num)
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);
+ else
+ omap_uart_smart_idle_enable(uart, 0);
return;
}
}
@@ -407,8 +412,14 @@ 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 (lsr UART_LSR_TEMT uart-can_sleep)
+ omap_uart_smart_idle_enable(uart, 1);
return IRQ_NONE;
}
--
1.5.4.3
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